Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Appendix F Working Group 2: Tropical and Extratropical Storms KENNETH ~ BLENKARN, Consultant, Leader ROBERT T. BUSH, Universe lknkships, Inc. PAUL JACOBS, Office of Meteorology, National Weather Service, National Oceanic and Atmospheric Administration CHESTER JELESNIANSKI, National Weather Service, National Oceanic and Atmospheric Administration SAUNDERS ~ JONES, Puerto Rico Marine Management, Inc. FOLLY MIRKIVICH, The Texas Shrimp Association DAVID J. H. PETERS, Conoco, Inc. FREDERICK H. SHARROCKS JR., Federal Emergency Management Agency This report examines forecasting issues related to tropical and ex- tratropical storms. The two different kinds of storms were examined as separate issues by the working group for several reasons. Topical storms (hurricanes) and extratropical storms involve different meteorological phe- nomena. The forecasting organization and intensity of focus on marine aspects are different for hurricanes. The two lands of storms affect differ- ent user groups or affect the user groups differently. There is some overlap of concern with other working groups, particu- larly the working group on wind, wave, and swell and the working group on collection, reporting, dissemination, and display. ~ the extent possible, this report focuses only on storm-related user needs and responses. A 74
75 major concern of the working group is with the impact of storm forecasting on safety. FINDINGS 1. Forecasting by the National Weather Service (NWS) and user response have been successful in minimizing loss of life due to hurricane occurrence in U.S. coastal regions. 2. User groups are aware of the uncertainties of hurricane forecasting and generally accept the burdens of false alarm evacuation for hurricanes. 3. There seem to be low prospects for technical improvements in forecasting hurricane tracks and behavior until all-weather satellite remote sensing is developed and made operational. 4. Decision makers of user groups and local authorities do work well to manage evacuations to ensure safety yet minimize economic loss. 5. For the foreseeable future, opportunities for making improve- ments and maintaining public confidence lie mainly in planning and man- agement of hurricane evacuation. 6. Rapid dissemination of real-time hurricane data from satellites, reconnaissance aircraft, and data buoys is vital to near-term forecasts and evacuation decision making for many user groups. 7. Significant improvements in accuracy and reliability of forecasting for extratropical storms would improve the operation of the fishing and shipping fleets. 8. The potential for improvements not withstanding, present marine forecasting of extratropical storms by the NWS is considered satisfactory by the fishing and shipping fleets. 9. The primary threat to shipping, and to many fishing vessels, is from "surprises," that is, from events that are qualitatively different from expectations based on forecasts. 10. Ib avoid surprises the masters of both fishing and shipping vessels depend very strongly on their own experience and judgment and on real- time weather data on board or from ships in the region. 11. There is a particular need to collect and disseminate weather observations from ships in storms and to do so at more frequent intervals than normal ship observations. 12. Marine weather conditions involving either explosive cyclogenesis or episodic waves may play a significant role in extratropical storm surprises. 13. While satisfied with marine forecasts, the fishing fleets do identify shortcomings in the NWS forecast product. 14. For the foreseeable future offshore petroleum industry exposure to extratropical storms is basically limited to Gulf of Mexico winter storms.
76 15. In spite of broad success in avoiding losses there remains some offshore industry vulnerability to unanticipated extratropical storm events. 16. Forecasting for future petroleum operations in remote, arctic offshore areas may be very dependent on weather data from improved satellite systems. RECOMMENDATIONS 1. Federal agencies and local authorities or users should place em- phasis on improving evacuation planning and decision making. 2. 1b support safe and effective evacuation decision making the NWS needs to ensure that real-time, or near-real-time, hurricane weather data gathering and distribution are maintained or even improved, such as by installation of improved coastal radar. 3. Some priority should be given to local measurement of hurricane storm tide measurements to verify and improve simulations and predictions. 4. As technology for satellite remote sensing of marine weather is de- veloped, that technology should be rapidly mobilized to provide operational capability and make ocean weather data available to NWS forecasters and other marine users. 5. The NWS should revitalize and reinforce the ship observation system in order to · obtain 3-hour or hourly interval observations from ships in storm areas; · improve the quality of observations and reduce the time lag between observation and the reception by forecasters, specifically promoting the use of automated equipment such as SEAS units; and · evolve procedures and communication systems necessary to provide storm weather data rapidly to vessel masters in the area of a storm. 6. 1b improve effectiveness of forecasts and of user operations, the NWS and cooperating agencies<should increase interaction and commu- nications with user groups; for example, strengthening activity of port meteorology officers and contact with fishing fleet groups. 7. While continuing efforts to advance basic technology regarding explosive cyclogenesis and episodic waves, the NWS should exploit emerging opportunities to provide mariners with guidance and warnings of such phenomena. 8. The NWS and offshore petroleum operating companies should reach accommodation and understanding to provide more offshore weather measurements and to utilize advanced radar systems.
77 9. Agencies concerned with ocean weather should reach agreements to establish a dedicated function responsible for improving the voluntary observing ship program. TROPICAL STORMS Forecasts Within the NWS there is a special organization, the National Hurricane Center in Miami, dedicated to the development of hurricane forecasts and the associated warnings to the populations and forecast users affected. The geographical regions of responsibility include the eastern North Pacific, but the bulk of activity is concerned with the western North Atlantic and adjacent seas. Over the years the NWS has developed computer simulations of hur- ricane processes and special hurricane data gathering methodologies. In performing the computer simulations for forecast purposes the National Hurricane Center utilizes weather data from the normal worldwide weather data network In addition, special attention is devoted to interpretation of satellite sensing and imagery data, and special reconnaissance aircraft are employed to gain direct atmospheric measurements within the hurricane itself. The center combines simulations and data to develop present condition descriptions of a hurricane and to project future changes in location, size, and intensity. Special priority is placed on identifying the sections of coastline expected to be influenced by landfall of the hurricane, the wind and tide to be experienced during passage of the hurricane, and the timing of such conditions. Shoreside Response The primary concern of shoreside populations and industry is to guard against loss of life during a hurricane. Consequently, shoreside communities in the coastal zone of expected landfall are generally "boarded up" and evacuated well in advance of a hurricane arrival. Residents of coastal areas subject to hurricanes have come to recognize and accommodate the uncertainties in the Hurricane Center forecasts and advisories. There have been some exceptions, but the overall history within the United States has been one of remarkable success in minimizing loss of life in hurricanes. Most exceptions have been attributable to individual exercise of poor judgment (defined by a consensus of what experienced, long-time residents would deem to be poor judgment). It must be noted that within
78 the United States, government authorities are not empowered to forcibly remove private citizens. The administrative processes for issuing evacuation advisories and the particular public authorities who may be responsible may vary significantly from one coastal region or community to another. The levels of planning and technical knowledge about local conditions may also vary widely. The Federal Emergency Management Agency (FEMA) has supported many local communities in developing guides to evacuation decision making and plans for evacuation. Such studies have included simulations by the NWS, with a computer program called SLOSH, to describe the details of anticipated local storm tide flooding for various levels of hurricane intensibr and paths of approach. Storm flooding is a key measure of hurricane damage potential, threat to life, and urgency of evacuations. Many coastal communities have not yet undertaken such formalized evacuation planning studies. Shoreside response also includes the securing and shutting down of var- ious industrial operations such as harbor facilities, power stations, chemical plants or refineries, and petroleum production. For many of these opera- tions, shutdown and restart are very costly. In such cases, evacuation often involves a very carefully staged process of gradually securing facilities and reducing staff well ahead of a hurricane approach, with final shutdown and evacuation of the last few key personnel being delayed as long as prudence allows. The object of such intense planning and management is to minimize the economic loss attributable to fake alarm shutdown. Many industrial operations may employ value-added forecasting efforts to fine tune decision making and evacuation scheduling. Value-added efforts are particularly employed for offshore oil and gas operations. Fishing Fleet Response Fishing fleets are very attuned to and respectful of hurricane warnings and advisories. Fishermen operate with the objective of being in port' se- cured, and evacuated before arrival of a hurricane. The consensus attitude of the fishing fleets is that the Hurricane Center provides appropriate and satisfactory forecasts and the history of the fishing fleets has been one of success in avoiding loss of life. Recent success comes in the face of some opposing influences. Quite apart from the threats of adverse weather, fishing tends to be an uncertain and risly business. There are strong economic pressures for fishermen to try to minimize the unproductive time spent in port without income. Even worse, sometimes there is a special attraction to fishing in advance of a hurricane. Fishermen have observed that changing ocean conditions at such times changes the movement patterns or behavior of some target species to
79 permit especially profitable catches. Thus some fishermen may be tempted to delay seeking shelter until the last moment. In a qualitative sense, the fishing fleet experiences the same incentive as industrial establishments to maintain operation as long as possible. The difference is that there is more safety risk for fishermen, and they are not organized to have value-added and focused forecasting services. One must not overemphasize the hazards, but the U.S. Coast Guard occasionally rescues fishermen in danger from a nurrlcane. Shipping Response Commercial merchant cargo and bulk vessels are generally very careful to monitor and respond prudently to hurricane forecasts. It is common practice to alter course or speed and delay saltings to give hurricanes a wide berth. This practice appears to be very successful in avoiding threatening conditions in the Caribbean and Gulf of Mexico as well as along the Atlantic Coast. In these areas hurricanes are intensively studied and tracked by the National Hurricane Center and response options for ships are numerous. In the mid-Atlantic, response options may be reduced and forecasting attention may be less, so that the overall experience, while basically successful, is not so comforting. The sinking of the Derbyshire in the western Pacific illustrates the practical problems of avoiding tropical storms in the open ocean. Special mention is made of the difficulties in obtaining adequate forecasts in such areas as the Indian Ocean, outside of the regions served by the NWS forecast system. This reinforces the consensus that in forecasting of tropical storms the NWS effectively performs its mission in support of ocean shipping through its domain of responsibility. Onshore Petroleum Response Since the inception of activity in the Gulf of Mexico, the offshore petroleum industry has been very cautious in trying to avoid risks to life posed by a hurricane. The accepted practice is to evacuate most personnel from offshore locations well in advance of ~ hurricane. Industry evacuation can involve a fleet of several hundred helicopters, supplemented by workboats and crewboats, to move the offshore work force of several thousands onto shore in time for evacuation in an orderly way along with a substantial complement of shoreside support personnel A common yardstick has this process under way 72 hours ahead of the hurricane. The offshore industry has become increasingly confident in the National Hurricane Center guidance and has gradually become somewhat more selective in the operating areas to be shut down and evacuated. Special attention is paid to the Hurricane Center forecast of storm track and
80 TABLE F-1 Representative Economic Lose of an Offshore HurTicane Evacuation Action Cost ~ = Daily oil production shut-in Representative shut-in term Price of oil shut-in Representative value of oil shut-ina Representative present worth losab Helicopter rental and operation for evacuation Mobile offshore drilling unit rentals during shutdown (unproductive expenditure) 800,000 bbl per day 3 days $15 per bbl $36 million S18 million S5 million S5 million , aTreated as "lose" of product. bTreated as deferral of revenue stream to depletion, 10 percent annual production decline, 10 percent discount interest rate. projected zone of expected landfall. The direct economic costs of an evacuation are substantial Able F-1 illustrates this with an estimate of the costs incurred for evacuation recently for hurricane Gilbert. Moreover, we must recognize that the logistic operation of quickly moving large numbers of people from offshore locations is not itself a totally risk-free undertaking. There are strong reasons to avoid unnecessary evacuations. The industry remains very cautious on safety, but steps are taken es- pecially to reduce the economic impact of shut-in of productions. Moves in the direction of more automation and remotely signaled closing of wells and treating facilities have permitted production to be maintained at least until the onset of hurricane conditions. Gas wells in particular often re- main in operation throughout an evacuation. In addition, some petroleum operating companies employ intensive value-added forecasting efforts in order to support evacuation decision making and the optimization of evac- uation timing. During the opening day of the workshop, David Peters, staff meteorologist with Conoco, described the program of his organization to provide specifically focused and continuously updated forecast advice to operations decision makers. It must be emphasized that these value-added efforts supplement rather than duplicate the information from the NWS. For example, a major part of the effort is concerned not with hurricane extreme conditions but on near-term local forecasts of conditions on the
81 fringes of the storm under which evacuation operations are conducted. The extent of value-added service employed throughout the industry varies with the size and technical strength of the operating organization and the economic and safety consequences of evacuation. The contributions that value-added services can make to safety assur- ance and reduction of economic loss critically depend on the hurricane meteorology data disseminated by the NWS. Specipcalk it is considered essential that the NWS continue with its present practice of gathering, pro- cessing, and rapidly transmitting basic data from data buoys, observing ships, satellite imagery, and reconnaissance aircraft flights through the nurncane. Needs and Priorities The NWS forecasting of hurricanes and user response has to be judged a success in guarding public safety. During the past two decades the number of deaths attibutable to hurricanes in the U.S. coastal regions has been very small This has been achieved by timely warnings and evacuations. Given the uncertainty in the forecasting of hurricane movement and behavior, the Hurricane Center warnings reflect a generous margin of error to ensure safety. One consequence is that a high percentage of the areas evacuated do not actually experience damaging hurricane conditions. These "false alarm" evacuations do represent financial loss to individuals and a burden to the local community generally. Nevertheless, most experienced residents of coastal communities new such losses as a necessary cost of living in hurricane-prone coastal areas. Recent success in guarding against the dangers of hurricanes could be grounds for contentment. There are, however, some shortcomings in the overall national management of the hurricane threat. . There have been some deaths blamed on fast moving or erratic hurricanes that have caught victims in exposed conditions. · There have been incidents of multiple false alarm evacuations in rapid succession. Evacuation compliance has tended to diminish for the later storms, fortunately without bad consequences so far. · There has been some public controversy over evacuation decision making; for example, regarding evacuation of Galveston during hurricane Gilbert Such occasions can eventually undermine public confidence and proper response to warnings. · There are several large population centers where the evacuation process has not passed a serious test. It is important to maintain or even increase public confidence in hurri- cane evacuation management. Improvements in the accuracy of hurricane
82 forecasts would naturally contribute markedly to this objective. Moreover, improvements in user community response would improve safety. The critical uncertainty in the forecasting of hurricanes lies in the prediction of storm track. The past 20 years has seen a steady accumulation of hurricane data and research to improve mathematical simulation of hurricanes and general rules for prediction. These efforts do not seem to have brought any really significant improvements in the reliability of track predictions. The technical challenge is indeed formidable. There may be fundamental randomness (or natural chaos) that can never be avoided. However, at the current state of technology, it would appear that the dominant barrier to improvement is the paucity of input data available. This appears to be the case for general weather forecasting as well as for hurricanes. Hence it is not reasonable to expect that a greatly intensified technical effort in hurricane track research would bring commensurate progams. The best prospects for improved hurricane forecasting may emerge from advances in satellite technology and operation that would permit all- weather remote sensing of meteorological data, especially over the oceans. Should satellite technology make adequate arrays of input data available, forecast accuracy can be expected to improve with present simulations. Even more improvements could then be expected from a major effort to develop more rigourous simulations with the expanded input data. How- ever, for now, forecast improvements regarding hurricane track are on hold. Low expectations for hurricane track forecast improvements in the near future tend to focus technology opportunities to enhancing user response. For many coastal areas, storm tide response depends on the local coastline, bay, or estuary configuration. Therefore the generalized hurricane tide forecasts by the NWS may realistically address the extent of flooding that should be expected locally. The NWS computer program SLOSH can simulate the local characteristics of storm tide. It is not, however, within the resources of NWS to provide real-time forecast simulations of storm tide at local sites during a hurricane approach. On the case studies performed with the SLOSH program, in collaboration with FEMA, the tide response has been simulated for representative hurricane conditions. Results permit local authorities to include realistic flooding scenarios in evacuation planning and to interpret Hurricane Center forecasts so as to include anticipated local storm tide in evacuation decision making. Quite apart from political questions about jurisdiction and funding of planning studies, the working group concludes on pure technical and engineering management grounds that
83 · local evacuation planning studies are appropriate and are likely to increase safety and reduce economic loss; and · for many local areas, storm tide simulations should be performed to support planning studies and decision malting. Whether storm tide simulations are made with the NWS SLOSH pro- gram or with a comparable analysis, it will probably be beneficial to make local storm-tide-related measurements during hurricanes. These measure- ments would permit verification of simulations, and, for example, provide assurance that particular locally important phenomena, such as wave setup, are reasonably reflected in the simulation. Verfication and local calibration may be important to ensure that erroneous tide simulations and predictions do not mislead decision makers or undermine public confidence. With accumulation of experience in managing evacuation it is to be expected that decision makers, both public and private, will strive to opti- mize the process in terms of both safety and economic impact. More and more users are likely to utilize value-added special forecasting efforts of the sort described by David Peters of Conoco. Not only must NWS's basic data service continue to support near-term forecasts, but further technical advances should be pursued. Many of the near-term forecasts, impor- tant to evacuation, could be markedly improved with real-time data from Doppler radar. New radar (i.e., NEXRAD) should be deployed at appro- priate coastal locations and NWS should collaborate closely with users to maximize benefits for evacuation decision makers. EXTRATROPICAL STORMS Marine forecasting of extratropical storms impacts mainly on the ship- ping industry and the fishing fleets. There is some influence also on offshore petroleum operations. Qualitatively, the needs of these user communities are similar, but there may be significant quantitative differences in the level of storm severity that is threatening. For example, winds and seas dangerous to inshore fishing vessels would represent only minor inconve- nience to a tanker on the high seas. Hence the working group has viewed the distortions between storms and normal sea conditions not as a simple numerical threshold, but rather regarding the level of threat to the user. Shipping Maritime shipping has provided descriptions of ways in which improved marine forecasts would improve the overall effectiveness of shipping op- erations. Presentations on the first day of the workshop by Capt. Robert S. Murray of Matson Navigation and Capt. Saunders ~ Jones of Puerto
84 Rico Marine summarized such benefits. Better intermediate forecasts (be- yond 3 days) would make for better ship route planning. Improved shorter range forecasts would permit more effective operational decision making for course corrections to optimize an ocean passage by avoiding rough weather. More information and detail about storm characteristics would significantly improve management of the ship to reduce hazards or to min- imize ship motions and cargo damage. The difficulties and risks of port approach and harbor-passage would be reduced with more accurate and more frequent forecasts of local coastal conditions. There is little doubt that significantly improved marine forecasts would have economic benefits for shipping and make ship operation easier. In- deed, one can reasonably speculate that very accurate and reliable fore- casts might improve shipping in ways that cannot now be envisioned. The shipping community, however, considers the present forecast services as satisfactory and is hard pressed to identify quantifiable benefits of better forecasts or ways in which shipping operation would be changed in any fundamental way. While expressing satisfaction with forecasts in the North Atlantic and North Pacific areas assigned to the NWS and cooperating agencies for sup- port of international shipping, shippers note some difficulties with forecasts in other regions. In the Southern Hemisphere, especially on less heavily traveled routes, forecast services are often less than satisfactory. Partic- ular mention is made to the difficulties in obtaining adequate forecasts in the Indian Ocean. There is some belief that the U.S. Navy as well as several other countries do provide marine forecast services superior to that received from U.S. civil sources. Canada, England, and Japan are almost universally noted as having superior services. Common observation is that Japanese broadcast fascimile maps can be received in a much clearer and more readable form. Fishermen as well as shippers note that Halifax marine forecasts are usually more accurate than adjacent U.S. services. In contrast to the consensus that marine forecasts are generally satis- factory, one can emphasize that weather-related shipping losses continue to occur. Marine insurance organizations report losses of approximately 500,000 tons each year in incidents that are weather related.This consti- tutes approximately 30 percent of all shipping losses. Ship captains and shipping managements suggest that most of the weather-related losses can be attributed to the occurrence of 'Surprises'' in weather developments. The word "surprises" is carefully chosen to convey that the issue is not one adequately captured in the usual assessments and measurements of the quantitative accuracy of forecasts. From the point of view of the mariner, a surprise event is a qualitative, not just quantitative, variance of the weather encountered from that anticipated on the basis of forecasts. Mariners
85 consider the occurrence of surprises as the governing threat to safety of transocean passage. Considered as a single class of events by mariners, surprises may in fact reflect several meteorological issues or phenomena The working group tried to segregate the issues for assessment: open-ocean resolution, explosive cyclogenesis, and episodic waves. Open-Ocean Resolution There is a perception among mariners that many of the surprise events in the open ocean involve weather phenomena that are too small or too rapidly changing to be detected, processed, and reflected in forecasts of the NWS system. Based on this perception and much tradition, ship masters depend very heavily on their own judgment in formulating the forecast to specifically guide their decision making. Many of these masters have a practical working knowledge of meteorology phenomena and much experi- ence in evaluating forecast projections for critical decisions. Attention on board ship narrows to the most important aspects of likely weather devel- opments and tends to respond immediately to changes in local conditions. In addition, mariners express the need for more detailed information and insight regarding particular storms and especially to the need for more data on present weather conditions. This is not surprising, given the emphasis of ship captains on the need to do their own near-term forecasts. It is almost unavoidable that meteorology specialists and forecasters within NWS must have some skepticism about the claimed merits of fore- casting by individual ship captains. This would all seem puzzling since any forecasts made on board would lack any significant amount of computa- tional power. Nevertheless, the preponderance of knowledgeable maritime opinion is that experienced captains do bring important forecasting capa- bilities into their decisions. The main problem is that these capabilities are employed at varying skill levels. Moreover, background in meteorology now seems to be less strong in the training of younger officers. This would suggest that in time the reliance on and effectiveness of shipboard judgment may decrease. fib provide extra support to ship captains, some shipping companies employ private, value-added, forecasting services. For the most part these value-added consultants supplement the basic NWS maps and forecasts. There are some differences of viewpoint in the meteorology community regarding the degree to which consultants can really bring enhanced skill levels to value-added forecasts. At the very least, a consultant can bring focused attention on weather along a specific client vessel's course and on that vessel's decision-making parameters. The consultant can give extra
86 attention to assessment of all data reported in the region of interest Opin- ions seem to be mixed in the shipping community as to me real usefulness of the value-added forecasters. Continuing and direct conversation between forecast consultant and the operations decison maker, a common practice in the offshore industry, does not appear to be common in shipping. Quite apart from questions of shipboard skill or value-added enhance- ment, safety of ships would be increased through general improvement of open-ocean forecasts to minimize occurrence of surprise storm condi- tions. There are technology elements that have great promise for improving forecast effectiveness. feasible. · Significant increases in ocean weather data density are technically · Finer grid weather simulations would be possible with increased computing power. · Advanced communication networks would permit rapid transmis- sion of data and forecasts directly between ships and forecast centers. Eventually, implementation of such technologies will come, not pri- marily for just marine forecasting, but as part of a overall global progress in weather data gathering and forecasting. Certainly gathering data over the ocean is a major part of data improvements generally, and satellite all-weather sensing may be the primary enabling technology. The working group has tried to focus on near-term needs and options for improving marine forecasting to reduce the threat of weather surprises for shipping. The most fundamental need is for more ocean weather observations. · NWS weather simulation and forecasts are particularly degraded by a lack of open-ocean weather data, especially in storms. · Mariners place very high value on real-time nearby observations of storm conditions. Open-ocean weather observations of storm conditions often critically depend on Voluntary Observing Ships (VOS). It is a major finding of the worlo;hop that the overall program of VOS does not function as effectively as it should. This is particularly true of VOS data from storm regions. Therefore the work group on tropical and extratropical storms strongly recommends that the Voluntary Observing Ship program be reinforced and aug- mented to make real-iime ocean storm data rapid) available to NWS and other marine users. Working group deliberations identified several issues that would influ- ence the effectiveness of an upgraded VOS program. Ship observations
87 under storm conditions should be submitted at more frequent intervals than routine ship observations; for example, submit storm observations every 3 hours or at hourly intervals. NWS would need to define very carefully the threshold to qualify for storm conditions. Storm observations should carry a special designation to distinguish them from more routine obsena- tions. The NWS communication system and procedure must be modified to respond more quickly to process storm observations in order to · permit NWS forecasters and value-added forecasters to follow storm conditions closely and issue warnings of changes; and · quickly transmit storm observations data back to the shipping fleet for timely on-board decision making. The present functioning of the VOS program is plagued by numerous problems of quality control, timeliness of reporting and communications processing, and shipboard procedures. For example, it seems that many ships report observations only during daylight watches because transmitting at night requires special overtime pay for the radio operator. The working group observes that impediments to weather observations for storm data should be removed in the interest of safety. These and other problems would be overcome by better mobilization of available measurement and communications technology. There are, of course, choices in equipment. As an effective first step, much progress would be made by placement of the NOAA-developed SEAS (Shipboard Environmental Data Acquisition System) units on the majority of observing vessels. A companion step would be placement of updated receiving units on ships, for example, to receive fascimile information, forecasts, and data by satellite. Achievements of the equipment update objectives will call for a strong initiative from management of NWS and cooperating agencies to bring a renewed dedication on the part of shipping companies and observing ships. NWS should also strengthen the technical advice and support provided to observing ships regarding communications equipment. As a part of this strengthening support, NWS should enhance the interaction with ships at the technical and operating staff levels. It is very important that port meteorological officer functions should be given higher priority for contact with ship personnel to enhance participation in the VOS program and improve effectiveness of communications to and from ships. Obtaining data from many scattered, even remote, operating locations is a challenge in many technologies and organizational settings, both public and private. An all too common approach is to specify the data that are desired, request that operating or line organizations provide the data, and then wait for data to flow in. The almost universal experience is that passive waiting will not maintain the required flow of data. It takes repeated or
88 continual attention from the data receiving organization to ensure that data gathering and transmittal are adequately prosecuted. Such attention must · verify that operating personnel can, in fact, expeditiously and easily gather and handle the data appropriately; · establish a basis for adequate tutoring of operating personnel in skills required for data activity; . equipment; perform at least some spot checking of data and calibration of provide feedback and encouragement to data gathering locations to maintain sufficient priority on data gathering; and · maintain open and reliable communication channels for data. Like the proverbial "free lunch," there is no such thing as free data. It requires nurturing attention from the receiving organization to keep data efforts functioning. Often the receiving organization only complains about the inadequacy of what is received. If the data are not sufficiently important for the receiving organization to confine required vigorous nurturing, the appropriateness of burdening operating personnel with data gathering is to be questioned. The assessment of the disappointing effectiveness of the VOS program strongly suggests that the program supers from a lack of nurturing. 1b achieve an effective VOS program, NOAA and the other agencies con- cerned with ocean weather should take initiatives to establish a dedicated function aimed at coordinating and nurturing the VOS program. Improvements of electiveness of the VOS program is the first priority in · · ~ trnprovzng forecasting and response to ocean storms. There are still other steps for NWS to focus on the special needs of marine forecasting, such as · increased forecaster training in the particular skills of ocean storm forecasting; · increased forecaster awareness of the needs of marine users; and · increased experience feedback from marine users. Explosive Cyclogenes~s As a matter of quantitative meteorology, explosive ~rclogenesis de- scribes extraordinary, low-pressure systems that deepen at rates of 1 millibar per hour or faster. Such storms are not well forecast by NWS simulations of ocean weather. They occur in the Northwest and Northeast Atlantic as well as in some North Pacific regions. Evidence suggests that occurrence of explosive cyclogenesis is most common near coastlines. There are in- dications that the phenomenon involves physical processes not presently captured in atmospheric simulation, at least not in operational programs.
89 While the term "explosive cyclogenesis" is not used by mariners, there is reasonably wide recognition of the threat of fast developing events, termed "bombs" in marine user parlance. The occurrence of poorly forecast bombs is dangerous for shipping. Efforts to improve forecasting deserve high priority in the interest of safety of life at sea. There have been special meteorology seminars on explosive cyclogene- sis, and there is some research moving forward. This work should continue. As always in such matters, progress is hampered by a lack of data. Scarcity of data in the air column over the oceans seems to be a particular problem, and direct data from upper-air probes are specifically needed. It appears that this need can most effectively be addressed by ship-launched devices. 1b the working group this suggests that the Automated Shipboard Aero- logical Program (ASAP) should be prosecuted vigorously as a complement to efforts to improve effectiveness of VOS. Without waiting for breakthroughs in the basic research, the NWS has developed some empirical guidelines to assist forecasters in recognizing and dealing with explosive cyclogenesis events. Parameter threshold values and indicative weather patterns are established to identity the likely occur- rence of explosive cyclogenesis. Further evolution and application of these empirical methodologies should continue. At present it appears that the greatest need is for more aggressive coaching of NWS forecasters in using the established guidelines. From the viewpoint of the mariner, it may be that NWS would improve service to users by specifically identifying storms with potential for explosive cyclogenes~. The simple statement, "This storm may be a bomb," would clearly alert ships to the particular uncertainties involved and to the need for extra caution. Increased education efforts are warranted to enhance mariner awareness and understanding regarding such events. Episodic Waves There is a body of anecdotal evidence to suggest the occurrence of waves dramatically larger than anticipated on the basis of the prevailing sea conditions. Technical specialists refer to such waves as episodic waves. The working group is aware of research that has been dedicated to such phenomena, in part sponsored by the U.S. Ship Structures Committee (with input from the Marine Board's Committee on Marine Structures) and in part by European institutions, especially in Norway, but there does not presently seem to be a clear resolution of questions about episodic waves. There does not for example appear to be technical consensus as to whether episodic waves reflect a particular physical phenomenon or are instead merely a manifestation of the statistical variability within a given sea state. Irrespective of the technical debates, mariners view the occurrence
go of impressively large and unexpected waves as a real threat to safety at sea. The term "rogue wave" is commonly used to classify such events. The issue is not strictly a forecasting question. However, the practical consequences are sufficiently serious that research efforts in the broader physical oceanography and naval architecture community should continue. The NWS should remain aware of progress and seek insights and under- standing. Any opportunities should be exploited to evolve toward useful warnings and to educate mariners about the phenomenon. There are some areas of the world (i.e., off the coast of South Africa) where seas interact with strong currents to produce very steep and poten- tially damaging waves. This may or may not be considered an episodic wave issue. Nevertheless, mariners are keenly aware of the hazards of such steep waves and try to avoid conditions under which they occur. Some forecasting services do attempt to provide warnings of possibly dangerous wave-current interaction. The NWS should consider including this concern in the marine forecasts for the ocean areas for which it is responsible. FISHING The information examined by the working group concerned the At- lantic and Gulf fishing fleets. Subsequent inquiries suggest that the group's assessments generally apply to other U.S. fisheries as well. In the North Pacific, Bering Sea, and Gulf of Alaska area, Lloyd's List reports more than 1,100 fishing vessels ranging up to 650-foot mother vessels with more than 200 people on board working in this area. Many of these vessels are home ported in Washington and Oregon. The replacement cost of a large modern processing mother ship can exceed $40 million. Extended voyages of over a month's duration are common. About seven vessels are lost each year, however, during the period from Novem- ber 1988 to January 1989, 15 vessels sank with many lives lost. This was partly due to exceptional weather with very strong winds and record low temperatures causing severe icing conditions. Icing of rigging and super- structure is a major cause of capsizing and foundering. Thus air and sea temperature and surface wind speed forecasts are critical during the winter to early spring period. Accurate forecasts of sea ice formation and move- ment are also very important to the fisherman to minimize losses of fixed gear, such as crab pots, and to indicate the limits of the ice edge. Fishing vessels are even more vulnerable than deep-sea ships to the exceptional waves that form in this area. In general, inshore and offshore fishing fleets have different concerns. The inshore fleet is made up of small vessels, perhaps 25 to 40 feet in length, and these vessels are engaged mainly in day fishing trips. They are equipped with only minimum communications gear. Forecasts are generally
91 received on very high frequency (VET voice broadcast or high frequency (HF) single sideband voice broadcast. Inshore fishermen also pay attention to local commercial television forecasters in decision making about plans for fishing. The offshore fleet is composed of larger vessels, many longer than 100 feet, to perhaps 150 feet. The voyages of the offshore fleet may last as long as 4 weeks and cover 1,OCO miles or more. These vessels monitor voice broadcasts for weather forecasts. However, the offshore fleets increasingly rely on facsimile broadcasts for forecasts. For most fishing vessels, economic pressures push them to operate on the margins close to conditions threatening damage or safety. They are vulnerable to storm phenomena even smaller than trading vessels. Fishing vessel captains are very dependent on their own interpretation of local data. They tend to maintain ship-to-ship radio voice communications with other fishing vessels in the region of their location to exchange weather obsena- tions. Even with prudence and considerable skill the fishing business can be a nerve wracking struggle requiring acceptance of a significant amount of weather-related risk. There can be little doubt that major improvements in forecasts would increase productive fishing time and reduce risks for the fishing fleets. The fishing fleets, in spite of difficulties and weather hazards, view the NWS in a very positive way and describe forecast services as satis- factory. Perhaps, contending directly with ocean weather daily as they do, fishermen are more aware of the inherent capriciousness of nature than are most landsmen. In any event, the fishermen look on the NWS as their protector, and feel they are well served. Although there is not very much direct contact between fishermen and NWS representatives, fishermen seem impressed with the helpfulness displayed by forecasters or other staff in the occasional direct request for assistance. Fishing fleet representatives do have some concern that the needs of fishermen may be overlooked as NWS changes policies, reorganizes the forecasting function, and modernizes communication equipment. The general expression of satisfaction notwithstanding, fishing repre- sentatives have a menu of shortcomings of the forecast service that they believe deserve some attention. · Fishermen find serious problems when they are presented with two very divergent forecasts, as sometimes happens when they are in the region of boundaries between two different NWS forecast areas. · Like the shipping captains, fishermen would like more details about the nature of the storm system that they may encounter.
92 · Even recognizing the uncertainties, fishing captains yearn for more extended forecast information and more frequent updates of conditions during a~storm. · A system for rapid reporting and broadcast of current weather observations by the fishing fleets is needed. · There is a need for more explanations when forecasts are changed drastically. · Sea surface and water column temperature are especially of interest to fishermen. There is a recurring message: fishermen wish U.S. forecasts were as good as those from Halifax, Canada. For many problems of fishing Beets, solutions may basically involve mobilizing available technology. This raises the question of the role of value-added services. Some fishing groups have engaged forecast services, but the outcome has most often not been satisfactory. The offshore fleet particularly may be scattered and far ranging, and it may be very difficult for a value-added consultant to target and communicate with such a fleet on an economical basis. The fishing fleets will continue to look mainly to the NWS for forecast needs. It is not the mandate of NOAA and NWS to provide fishing fleets with the kind of specifically tailored guidance that a good value-added forecaster would provide. And it is not likely that public policy will change that mandate in the foreseeable future. While there is some contact betweeen fishermen and NWS, it is the assessment of the working group that a more concerted effort of contact and discourse beween NWS personnel and fishing fleets is needed. It is expected that there remam several potential adjustments of forecast operations and services that NWS could undertake to overcome shortcomings of forecasts for fishermen without departing from its mandate or from current NWS policy. Meetings with fishing fleet organizations could identify useful adjustments and could smooth user transitions as NWS makes organizational changes or modifies the forecast delivery communications system and enhances fishing fleet involvment in VOS. For the inshore fleet, major improvement could come from progress on the general problem of local area forecast resolution. It is expected that available technology could bring such progress. The major barrier seems to be institutional and to a large degree a question of funding. It may be that progress on local forecast resolution will require local initiatives. 1b illustrate the potential role of local initiatives, several workshop attendees cited local surf forecasts available in southern California. Certainly the fishing fleet should be a part of any local forecast initiative.
g3 OFFSHORE PETROLEUM The offshore petroleum industry has conducted operations in most of the coastal regions of North America: the Gulf of Mexico, U.S. At- lantic Coast, Newfoundland-Labrador, the West Coast (especially southern California), Gulf of Alaska, Bering Sea, and Beaufort Sea. These oper- ations have involved substantial vulnerability to ocean storms, especially exploratory drilling and construction. Because of this vulnerability, the ofI- shore industry has extensively utilized value-added consultants to provide specialized forecasts to support operations. These forecasting programs have commons had several particular attributes: · frequent and continuing conversations between the forecaster and the onsite superintendent (decision maker) to ensure clear understanding of operating need and most useful interpretation of the forecast; · continual feedback of onsite weather observations to the fore- caster's office; and · adjustment of forecast attention to emphasize the specific weather variable most important to operating decision making. Industry forecast progress culminated in the forecasting effort to sup- port deep-water exploratory drilling off the mid-Atlantic Coast. This pro- gram has been presented in the technical literature and was described in a workshop presentation by Allen M. Reece of Shell Oil Company. Vety focused forecasts were targeted at predictions of specific drilling vessel motions. Onboard computer systems employed forecasts together with real-time data and simulations of ship motions to provide expert system guidance to storm preparation decisions. The overall forecast effort con- tributed to the prosecution of a very difficult drilling campaign without major storm mishaps. The offshore industry places high value on the potential benefits of value-added forecast services. The foregoing is not to suggest that the offshore industry has been without storm-related accidents. The tragic sinking of the semisubmersible drilling unit Ocean Ranger on Grand Banks- heads the list. There have also been several incidents in which jackup drilling barges capsized or collapsed during winter storms in the Gulf of Mexico. Under current industry conditions, operations have been reduced to a significant degree. Lack of success in exploratory drilling has been the governing issue, not just the fall in oil prices. The result is that industry concern with extratropical storms has almost exclusively narrowed to the Gulf of Mexico winter storms. With the long experience history in the Gulf of Mexico, operating practices have been improved to reduce weather vulnerability, and there is less need for intensive value-added forecasting for many operations. In fact, many operating organizations now rely only on NWS forecasts.
94 Even with advances in operating practices, there remains a safety vulnerability for certain kinds of operations to frontal systems, local squalls, or other rapidly changing storm conditions. Jackup barges under tow, construction barges, workboats, and helicopters can be caught in exposed locations by severe weather and endangered. Not suprisingly, the most immediate path to improving forecasts of storm events lies in expanding the presently utilized weather data base. The numerous offshore platforms in the Gulf of Mexico are at locations where weather observations would provide valuable additions to the NWS data base. Oil companies do make weather measurements on many plat- forms. Some of these data streams are sent to the NWS system, many are not. Operators of offshore platforms should do more to provide ocean weather observations, and there is a specific cooperative project under way to improve this response of the offshore industry. It should be noted, however, that there is another side to the story. The NWS has not al- ways responded in ways that encourage petroleum operating companies to provide observations. · Oil company staff and technical specialists who have been involved in offshore weather measurements often conclude that it is hard to give data to NWS. NWS has seemed very pedantic in speckling instruments for mea- surements. · Operating personnel offshore do not see much encouraging evi- dence that data submitted are used by NWS or improve local forecasts in any perceptible way. The working group concludes that the NWS and the offshore industry should make a concerted effort to reach accommodations and workable arrangements for submittal of critical weather data from offshore and then to enhance NWS utilization of such data. There are many reasons to expect that near-term forecasting of fronts, squalls, or other storms that threaten offshore operating safety in the Gulf could be significantly improved with data from enhanced radar. The work- ing group recommends that NWS and the offshore industry carefully discuss the deployment and most effective utilization of NEXRAD equipment at coastal locations adjacent to offshore operations. It may even be appropri- ate to investigate the merits of locating a NEXRAD unit on an offshore platform. Aside from continuing production operations in the Gulf of Mexico and off southern California, there is little present activity in offshore areas adjacent to the United States. Seasonal exploratory drilling does continue on a very limited basis in northern waters off Alaska. The industry has recently taken new, unexplored lease positions in the Chukchi Sea, north of
9s the Bering Strait. The pace of exploratory drilling and future production in these areas is uncertain. It is not realistic to make projections of forecasting needs for such operations at this time. Should the need arise for higher quality forecasts in these offshore areas, scarcity of weather data may be a real limitation. Development of all-weather satellite systems for weather data may be particularly critical for remote, northern data-scarce locations. DREDGING The dredging industry is subject to several classes of marine weather hazards. During mobilization to a worksite, a dredge may undertake a long distance ocean tow. Dredges are not particularly seaworthy and are veer vulnerable to storm losses. In most respects, the towing of dredges resembles the towing of Ashore jackup drilling barges. For both kinds of vessels, tows may take them through remote regions having very meager climatology for planning or forecasting for towing operations. Overall reduction of hazards is likely to come largely from upgrading worldwide forecasting. During operations, dredges occupy a very specific site. The operating efficiency, safety, and damage risk for an operation depend very critically on reliability of forecasts. Dredges can be very vulnerable. Some units may be at risk when sea states exceed 3 to 4 feet significant height. The implementation of safetr measures for most dredging operations is very much governed by local weather forecasts. 1b this extent dredges are like the inshore fishing fleet in need of meaningful improvement in the resolution of local forecasts. ~ For severe storms, safety and protection of the equipment calls for the dredge to be towed from the worksite to a sheltered anchorage. This takes a long time, 12 to 24 hours might be representative tow times. For some of the more exposed operating locations the tow time may be even longer and the vulnerability especially high. Longer range forecasts may be the only improvements in forecasting that would truly protect such operations. With that exception, it appears that dredging would benefit from most of the improvements for other coastal users.