Forecasting Atlantic Hurricanes at The. National Hurricane Centre. Centre. Chris Landsea Science and Operations Officer.

Transcription

1 Forecasting Atlantic Hurricanes at The National Hurricane Centre Chris Landsea Science and Operations Officer National Hurricane Centre 16 June, 2010

2 Forecasting Atlantic Hurricanes at The National Hurricane Center Chris Landsea Science and Operations Officer National Hurricane Center 16 June, 2010

3 Outline: National Hurricane Center Who we are and what our mission is. Monitoring Hurricanes What tools we have access to. Day-to-day Forecasting of Hurricanes - Models and meteorologists. Changes in Store for 2010 and Beyond New products and improvements. Seasonal Forecasting How it is done and how skillful it is.

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5 NHC MISSION To save lives, mitigate property loss, and improve economic efficiency by issuing the best watches, warnings, forecasts and analyses of hazardous tropical weather, and by increasing understanding of these hazards NHC VISION To be America s calm, clear and trusted voice in the eye of the storm, and, with our partners, enable communities to be safe from tropical weather threats

6 Energy Release ( Cylinders ) Outflow ( Exhaust ) Ocean ( Fuel( Fuel )

7 What is a Hurricane? A type of Tropical Cyclone Closed surface circulation Winds rotate counter-clockwise Produces organized thunderstorm activity Tropical Depression Sustained winds are less than 39 mph Tropical Storm Sustained winds are between mph Hurricane Sustained winds are 74 mph or greater

8 Saffir-Simpson Hurricane Scale Categorizes hurricanes by wind speed Tropical Storm mph (34-63 kt) MAJOR HURRICANES Category 1 Category 2 Category 3 Category 4 Category mph (64-82 kt) mph (83-95 kt) mph ( kt) mph ( kt) > 155 mph (> 136 kt) Alberto (2006) Katrina (FL ) Frances (2004) Katrina (LA ) Charley (2004) Andrew (1992) Allison (2001) Claudette (2003) Isabel (2003) Wilma (FL- 2005) Hugo (1989) Camille (1969)

9 Wind-caused Damage Storm Surge Inland Flooding Tornados

10 Before Katrina David & Kimberly King Waveland, MS

11 After Katrina David & Kimberly King Waveland, MS

12 Global Tropical Cyclones Average: 85 Per Year World Wide

13 Atlantic Hurricane Basin Climatology

14 Coastal County Population, Texas to Maine ,000,000 45,000,000 40,000,000 35,000,000 53% of the U.S. population now live within 50 miles of the coast Population 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000, Year

15 U.S. Coastlines: Then and Now 1926 Great Miami Hurricane: $ Billion Today Miami Beach 1926 Miami Beach 2006 Wendler Collection Joel Gratz 2006

16 THE NATIONAL HURRICANE CENTER: IS THE REGIONAL SPECIALIZED METEOROLOGICAL CENTER (RSMC) FOR THE WMO RA-IV HURRICANE COMITTEE HAS OVERALL U.S. NATIONAL WEATHER SERVICE RESPONSIBILITY FOR TROPICAL CYCLONE FORECASTS AND WARNINGS FOR THE ATLANTIC AND EASTERN PACIFIC OCEANS EAST OF 140º WEST LONGITUDE (HURRICANE SPECIALIST UNIT) ISSUES MARINE FORECASTS AND GRAPHICAL PRODUCTS FOR PORTIONS OF THE ATLANTIC AND EASTERN PACIFIC (TAFB)

17 TAFB Marine Forecasts

18 TAFB produces 57 graphic products & 48 text products each day N Offshore Forecast Areas 31 0 N 35 0 W W High Seas Forecast Areas 7 0 N S ~ 14 million sq. nautical miles

19 Wave Height & Surface Wind Forecasts

20 TAFB Dvorak Classifications Katrina August 24 Rita September 18

21 A Typical Day in 2010 Data Available at NHC

22 A Typical Day in 2010 Data Available at NHC

23 A Typical Day in 2010 Data Available at NHC

24 Miss Piggy Built in 1976 at Lockheed-Martin, Marietta, Georgia Kermit Built in 1975 at Lockheed-Martin, Marietta, Georgia Gonzo Built in 1994 at Gulfstream Aerospace Corporation in Savannah Georgia

25 RECONNAISSANCE FLIGHT PATH Aircraft ALPHA Pattern

26 Within the Eye of Hurricane Georges eyewall low clouds above sea-surface

27 Tropical Cyclone Forecasting

28 KEY TEXT PRODUCTS Tropical Weather Outlook Discusses significant areas of disturbed weather and their potential for development out to 48 hours Public Advisory v Provides current coastal watches and warnings, storm position, intensity, motion, and potential storm surge/tides, rainfall, and tornadoes Forecast/Advisory v Provides coastal watches and warnings, and current and forecast center location, maximum intensity and size Discussion v Provides reasoning and uncertainty for forecast of the storm Surface Wind Speed Probabilities v provides percent probabilities of sustained wind speeds equal to or exceeding 34, 50, and 64-knots at coastal locations for next 120 hours

29 Graphical Tropical Weather Outlook became operational in 2009 will provide exact chance for formation Shows on satellite pictures the current locations of areas of disturbed weather and provides categorical estimates of development potential over the next 48 hours.

30 Genesis of Bill was well predicted by the GFS (another case of good GFS forecasts of eastern tropical Atlantic genesis). This is a series of model forecasts of sea level pressure and 850 mb winds/vorticity, starting from 126 hours out, all verifying at the time of genesis (0600 UTC 8/15/09).

31 Claudette s formation was not well anticipated by the GFS or by the NHC forecasters (another case of models underforecasting Gulf genesis). This is a series of model forecasts of sea level pressure and 850 mb winds/vorticity, starting from 126 hours out, all verifying at the time of genesis (0600 UTC 8/16/09).

32 NHC Forecast Cone Represents the probable track of the center of the tropical cyclone. Formed by connecting circles centered on each forecast point (at 12, 24, 36 h, etc.) Size of the circles determined so that, say, the actual storm position at 48 h will be within the 48-h circle 67% of the time.

33 Hurricane Ike Track models

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35 Improvements in Forecast Models and Increased Satellite Data has Led to a Large Reduction in NHC Track Errors Errors have been cut in half over the past 15 years was best year ever.

36 Guidance Trends 2 Days GFS/GFDL/ECMWF are traditionally the better performers, while UKMET and NOGAPS have lagged behind in recent years.

37 Guidance Trends 5 Days Relative performance at 120 h is more variable, although GFSI has been strong every year except GFDL performance at the longer ranges is not as strong.

38 Cone versus Size & Impact The Cone DOES NOT denote area of impact.

39 Cone versus Size & Impact as Ike s hurricane force winds demonstrate

40 Tropical Cyclone Wind Field became operational in 2009 Shows: Wind field Past track Current watches/ warnings

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42 Atlantic Intensity (Wind) Error Trends No progress with intensity h intensity forecasts are likely to be off by one SSHS category, and off by two SSHS categories perhaps 5-10% of the time.

43 Lots of problems with dynamical guidance for predicting intensity change

44 Wind Speed Probabilities Shows the chance of a particular event occurring at a specific location

45 Storm Surge Probability became operational in 2009 available in 1 ft increments from 2 to 25 ft run when a Hurricane Watch or Warning is in effect Chance of surge > 2 ft Chance of surge > 10 ft

46 Height Above Height Above Ground Level (Inundation) Reference Level

47 Hurricane Hotline v Other NWS/NCEP National Centers (HPC, OPC, SPC) v Local NWS Offices v DOD v Other federal agencies Forecast Coordination NWS USAF USN Hurricane Hotline Locations

48 WORLD METEOROLOGICAL ORGANIZATION Regional Association IV (RA-IV) Coordination RSMC Miami RSMC= Regional Specialized Meteorological Center; RA-IV countries include Caribbean area, Central America, Mexico, Canada, and Bermuda.

49 Hurricane Dean watches and warnings

50 OPERATIONAL COMMUNICATIONS WITH KEY DECISION-MAKERS WITH THE MEDIA White House Photo President George W. Bush and Deputy Chief of Staff Joe Hagin, center, during a video teleconference with NHC and emergency managers WITH INTERNATIONAL PARTNERS WITH THE PUBLIC

51 OUTREACH AND EDUCATION National Hurricane Preparedness Week FEMA workshop for emergency managers Hurricane Awareness Tours National Hurricane Conference (& others) WMO workshop for international meteorologists U.S. Interdepartmental Hurricane Conference

52 Possible Changes for 2010 and Beyond Extend Lead Time for Hurricane/ Tropical Storm Watches and Warning Implemented for 2010 Extend Watches to 48 hours (currently 36 h) Extend Warnings to 36 hours (currently 24 h) Storm Surge Warnings Proposal drafted At least 2-3 years away NHC requests comments Population 50,000,000 45,000,000 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000,000 0 Coastal County Population, Texas to to Maine 53% of the U.S. population now lives within 50 miles of the coast Year Evacuation decisions in many cases must be made more than 24 h before landfall H H 7 Day Track Forecasts Within the next decade Storm Surge Warning

53 Changes to Tropical Cyclone Watch/Warning Lead Times in 2010 Lead time virtually unchanged while skill in track forecasting has improved NHC in fact frequently does issue watches and warnings at longer lead time than Directive indicates Key evacuation decisions now need to be made before 24 h and in some cases before 48 h Population 50,000,000 45,000,000 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000,000 0 Coastal County Population, Texas to to Maine 53% of the U.S. population now lives within 50 miles of the coast Year

54 New Definitions of Tropical Storm Watch/Warning Tropical Storm Watch: tropical storm conditions are possible somewhere within the watch area within the next 48 hours. Tropical Storm Warning: tropical storm conditions are expected somewhere within the warning area within the next 36 hours.

55 New Definitions of Hurricane Watch/Warning Hurricane Watch: hurricane conditions are possible somewhere within the watch area. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated onset of tropical storm force winds. Hurricane Warning: hurricane conditions are expected somewhere within the warning area. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane warning is issued 36 hours in advance of the anticipated onset of tropical stormforce winds.

56 Addition of explicit probability in Tropical Weather Outlook (50%) TROPICAL WEATHER OUTLOOK NWS NATIONAL HURRICANE CENTER MIAMI, FL 200 PM EDT TUE SEP PM TUE SEP Satellite Image: 122 PM FOR THE NORTH ATLANTIC CARIBBEAN SEA AND THE GULF OF MEXICO <30% 30-50% THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL STORM BERTHA.LOCATED ABOUT 190 MILES NORTH-NORTHEAST OF BERMUDA. THE AREA OF LOW PRESSURE LOCATED ABOUT 950 MILES EAST OF THE LESSER ANTILLES HAS CHANGED LITTLE IN ORGANIZATION THIS MORNING. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR DEVELOPMENT AND THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO. THERE IS A MEDIUM CHANCE 50 PERCENT OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. $$ FORECASTER BROWN Note: Probabilities at the extremes (0% or 100%) are preceded by the word near. Near 0% or Near 100%

57 New Public Advisory Format Section headers added Storm information first Changes to watches and warnings in the current advisory are highlighted Bulleted summary of all watches and warnings in effect

58 New Public Advisory Format Section headers Discussion of forecast motion and intensity and other pertinent information Storm hazards and impacts, shown by type

59 New Tropical Cyclone Update Format Example 1: Notifying users of change in status ZCZC MIATCUAT4 ALL TTAA00 KNHC DDHHMM TROPICAL STORM CLAUDETTE TROPICAL CYCLONE UPDATE NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL PM EDT SUN AUG DEPRESSION BECOMES TROPICAL STORM CLAUDETTE... DATA FROM THE NOAA DOPPLER RADAR IN TALLAHASSEE FLORIDA INDICATE THAT SURFACE WINDS ASSOCIATED WITH THE DEPRESSION HAVE INCREASED TO 40 MPH...65 KM/HR...INDICATING THAT THE DEPRESSION HAS BECOME A TROPICAL STORM....SUMMARY OF 1215 PM EDT INFORMATION... LOCATION N 84.6W ABOUT 580 MI KM ESE OF CORPUS CHRISTI TEXAS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR PRESENT MOVEMENT...NORTHWEST OR 320 DEGREES AT 14 MPH...23 KM/HR MINIMUM CENTRAL PRESSURE MB INCHES $$ FORECASTER XXXX

60 Example of a Post Tropical Cyclone Last advisory for Hurricane Omar (2008) Lost all its central deep convection, so was no longer a tropical cyclone Was not yet extratropical (no fronts attached) Was not a remnant low still had winds to 40 knots Omar (2008) Station Duty Manual Guidance on declaration of a post-tropical cyclone or remnant low: In general, 18 hours should elapse between the loss of organized deep convection and the cessation of advisories. Leeway to go shorter when confidence is very high (over very cold water) that organized convection will not return.

61 Post Tropical A FORMER TROPICAL CYCLONE. THIS GENERIC TERM DESCRIBES A CYCLONE THAT NO LONGER POSSESSES SUFFICIENT TROPICAL CHARACTERISTICS TO BE CONSIDERED A TROPICAL CYCLONE. POST TROPICAL CYCLONES CAN CONTINUE CARRYING HEAVY RAINS AND HIGH WINDS. FORMER TROPICAL CYCLONES THAT HAVE BECOME FULLY EXTRATROPICAL...AS WELL AS REMNANT LOWS...ARE TWO SPECIFIC CLASSES OF POST TROPICAL CYCLONES Post Tropical Extratropical Low Any cyclone (including post tropical) whose primary energy source is temperature contrasts between warm and cold air masses Remnant Low Post tropical cyclone that no longer has the convective organization required of a tropical cyclone, maximum sustained winds less than 34 kt

62 Post Tropical LET S SAY THAT A SYSTEM HAS LOST THE DEEP CONVECTION REQUIRED OF A TROPICAL CYCLONE BUT IT DOES NOT YET HAVE ANY FRONTAL CHARACTERISTICS. BUT, IT STILL HAS MAXIMUM WINDS THAT EXCEED 34 KNOTS. FORECAST POSITIONS AND MAX WINDS INITIAL 01/1500Z 46.5N 46.5W 40 KT...POST-TROPICAL 12HR VT 02/0000Z 48.9N 45.6W 40 KT...POST-TROPICAL 24HR VT 02/1200Z 52.2N 43.5W 40 KT...POST-TROP/EXTRATROP 36HR VT 03/0000Z 55.0N 39.8W 40 KT...POST-TROP/EXTRATROP 48HR VT 03/1200Z 56.0N 33.0W 40 KT...POST-TROP/EXTRATROP 72HR VT 04/1200Z 56.5N 20.0W 40 KT...POST-TROP/EXTRATROP 96HR VT 05/1200Z...ABSORBED

63 Saffir Simpson Hurricane Wind Scale Surge, rainfall, and pressure fit the scale like a square peg in a round hole KATRINA (3) IKE (2) CHARLEY (4) References to the scale in Public Advisory will say Saffir-Simpson Hurricane Wind Scale

64 Seasonal Forecasting Seasonal forecast predictors Current forecast methodology Verification of 2009 seasonal forecast NOAA s 2010 seasonal prediction

65 Dr. Bill Gray Colorado State University Father of seasonal hurricane prediction

66 Origin of seasonal forecasting El Niño Years Years after El Niño (like 2010) From Gray 1984

67 El Niño Occurs every 3 to 5 years Affects weather patterns by changing thunderstorm development Generally reduces Atlantic hurricane activity

68 El Niño La Niña

69 El Niño versus La Niña Upper winds Hello there it Extra shear and dry sinking air over the Atlantic basin. Upper winds Hello there it Less shear and sinking air over the Atlantic basin in La Niña.

70 El Niño

71 La Niña

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73 Vertical Wind Shear Tropical cyclones develop in low shear environments, less than about kph. June-July shear foreshadows later season shear. Important because about 90% of all major hurricanes strike after 1 August.

74 winds In general, lots of shear in the basin Upperlevel Lowerlevel winds

75 200mb zonal wind anomalies (m/s) during June-July of 10 ENSO events. El Niño La Niña

76 Sea-Level Pressure Known to be a seasonal predictor for a century. Pressure is an indicator for multiple qualities in the atmosphere. Low early season pressures often linked to active hurricane seasons

77 Composite map of June-July surface pressures during 10 active hurricane seasons Higher than normal Lower than normal

78 Pressure isn t everything!

79 Sea-Surface Temperatures (SSTs) Warmer waters generally mean a more active hurricane season. Higher SSTs lead to more instability in the lowest layer of the atmosphere. Positioning of SST anomalies can change local weather patterns. Long-term cycle also important.

80 June-July SST anomalies during 10 active hurricane seasons Colder than average Warmer than average

81 August-October SSTs minus C

82 North Atlantic SSTs and Quadratic Trend Residual Atlantic Multidecadal Oscillation Enfield and Cid (2009)

83 Florida and U.S. East Coast Major Hurricane Strikes Cold Atlantic Warm Atlantic

84 Global Climate Model Forecasts Global Climate Models (GCMs) are now able to simulate the number and strength of a given storm season. Skill is derived from the model forecasts of El Niño and Atlantic SSTs, which primarily control the large-scale Atlantic conditions. Hindcast skill is comparable to statistical techniques and appears to be new independent information for the forecaster.

85 Storm Counts and ACE Index ATL Below Average Year 2009 Atlantic Basin CFS is predicting 5.2 storms versus a 7.8 storm climatology. ACE Index is only 58% of Normal

86 2009 Actual

87 NOAA Forecast Methodology 1) Assess states of the ocean and atmosphere. 2) Use model forecasts for El Niño/Atlantic SSTs and incorporate any analog techniques and dynamical model forecasts. 3) Predict range of overall activity and probabilities of above-, near-, and belowaverage seasons. 4) Qualitative/Quantitative process. 5) No forecast of hurricane landfalls, just the total seasonal activity for the entire basin.

88 NOAA s s 2009 Atlantic Hurricane Outlook Season and May 2009 Aug 2009 Activity Type Outlook Outlook Observed Activity Climatology Chance Above Normal 25% 10% 33% Chance Near Normal 50% 50% 33% Chance Below Normal 25% 40% Quiet 33% Named Storms Hurricanes Major Hurricanes ACE % of Median % % 60% 100%

89 Sea-surface temperatures in the tropical Atlantic were slightly warmer than average.

90 El Niño developed during the summer

91 Anomalous vertical wind shear August-October 2009

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93 Mean Absolute Error for May and August NOAA Forecasts 8 *Statistically significant difference from climatology year Clim atology NOAA May Fcst 5 year Clim atology NOAA August Fcst * Forecast Error August forecasts improve the number of tropical storms and hurricanes forecast by about 1 per season. * 2 1 * * 0 May Aug May Aug May Aug May Aug Tropical Storms Hurricanes Major Hurricanes ACE/10

94 2010 NOAA Seasonal Outlook Current Conditions Model Projections Outlook Format Caveats

95 Atmospheric Multi-Decadal Signal Above-Normal Seasons feature: Reduced vertical wind shear in boxed region is critical for hurricane formation. Weaker easterly trade winds in boxed region are associated with northward shift of the ITCZ and a more favorable African Easterly Jet (AEJ). Enhanced cyclonic circulation is aligned along equatorward flank of AEJ (boxed region), and provides energy to developing tropical disturbances.

96 Warmer SSTs in the Tropical Atlantic Latest Weekly SST Departures ( o C) Monthly SST Departures ( o C) The Main Development Region (MDR) for Atlantic hurricanes (Green Box) is currently experiencing record warm SSTs, with departures exceeding +1.5 o C nearly everywhere east of the Caribbean Islands. SST departures in the MDR increased sharply during February-April 2010 (Top), and reached record levels in March and April. These departures are much larger than elsewhere in the global Tropics (Bottom), and are an indicator.

97 February-April 2010 Sea-Level Winds and Departures from Normal The tropical North Atlantic warmed significantly during Feb-Apr 2010, in association with a disappearance of the northeasterly trade winds (Top) and a much weaker low-level ridge (i.e. anomalous cyclonic circulation, Bottom) in the area north of the MDR (indicated by green boxed region).

98 February-April hPa (near 35,000 ft) Jet Stream Winds and Departures During Feb-Apr 2010, the weakening of the northeasterly trade winds near the ocean surface was associated with a southward shift of the Atlantic jet stream, which extended from Florida to southern Europe.

99 Standardized Indices for the North Atlantic Oscillation, East Atlantic Pattern, and Arctic Oscillation During February-April 2010, the record warm SSTs in the MDR, and the disappearance of northeasterly surface trade winds north of the MDR, were linked to El Niño, a strong negative phase of the North Atlantic Oscillation (NAO, Top Left) and the positive phase of the East Atlantic (EA) circulation pattern (Top Right). During February, the NAO and EA patterns were related to the negative phase of the Arctic Oscillation (Bottom).

100 Pacific Ocean Conditions are favorable for La Niña a to Develop during the Summer Months Weekly SST ( o C) Centered on 19 May 2010 Subsurface Temperatures ( o C) 5-day Mean Centered 18 May 2010 El Niño has dissipated. Negative SST anomalies are now present in the equatorial Pacific. Sub-surface temperatures are below average across the eastern half of equatorial Pacific. Equatorial Upper Ocean (0-300m) Heat Content 180 o -100 o W Since March 2010, the oceanic heat content has decreased markedly.

101 EUROSIP (ECMWF, UKMet, Meteo-France) Climate Model Forecasts

102 U.S. Climate Forecast System Model

103 Model-Based El Niño/ La Niña (ENSO) Forecasts for the Niño 3.4 region El Niño ENSO-Neutral La Niña The ENSO forecast models are predicting either ENSO-Neutral or La Niña conditions during the Atlantic hurricane season. The forecasts are increasingly indicating La Niña during Aug-Oct (ASO) 2010 (Figure courtesy of the International Research Institute).

104 Expected Conditions During August-October 2010 Much Warmer Atlantic SSTs The set of conditions expected during August-October 2010 mainly reflects the ongoing high activity era in the Atlantic basin, above-average Atlantic Ocean temperatures, and a possible La Niña-related reduction in vertical wind shear.

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106 The 2010 Atlantic Outlook in a Historical Perspective NOAA s 2010 Atlantic hurricane season outlook indicates a 70% probability of an ACE range of 155%-270% of the median. An ACE value above 175% of median reflects an extremely active (also called hyperactive) season.

107 Putting Seasonal Forecasts in Perspective If a perfect seasonal forecast predicts: 7 Named Storms 4 Hurricanes 1 Major Hurricane Long-term Average = 11, 6, and 2 Do you think it is going to be a bad year?

108 It only takes one in your area for it to be a bad season!

109 Caveats: NOAA Atlantic Hurricane Outlooks 1)Have quite limited skill (correct in 2008, busted in 2006 and 2007) 2)Says nothing about US (or other countries) hurricane landfalls 3)Even quiet seasons can have devastating landfalling hurricanes (e.g., Hurricane Andrew in 1992 with a quiet 4 hurricanes) 4)Local (city, county, state) officials and residents are advised to NOT make any changes to their annual hurricane preparations based on this forecast (i.e., don t use the forecast)

110 Five Major Landfalling Hurricanes in Florida

111 We want you to be prepared! Thank you.

112 Outline: National Hurricane Center Who we are and what our mission is. Monitoring Hurricanes What tools we have access to. Day-to-day Forecasting of Hurricanes - Models and meteorologists. Changes in Store for 2010 and Beyond New products and improvements. Seasonal Forecasting How it is done and how skillful it is.

113 Forecasting Atlantic Hurricanes at The National Hurricane Center Chris Landsea Science and Operations Officer National Hurricane Center 16 June, 2010

114 New Tropical Cyclone Update Format Example 2: Notifying users change in status is forthcoming No Change to Previous Storm Information, no Summary Included ZCZC MIATCUAT2 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION SEVEN TROPICAL CYCLONE UPDATE NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL PM EDT MON AUG PRELIMINARY REPORTS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT INDICATE THAT TROPICAL DEPRESSION SEVEN HAS STRENGTHENED. A SPECIAL ADVISORY WILL BE ISSUED WITHIN THE NEXT 30 MINUTES TO UPGRADE THE DEPRESSION TO A TROPICAL STORM...TO UPDATE THE INTENSITY FORECAST...AND TO ISSUE NEW WATCHES AND WARNINGS FOR HISPANIOLA. $$ FORECASTER PASCH

115 New Tropical Cyclone Update Format Example 3: Update watches or warnings No Change to Previous Storm Information, no Summary Included ZCZC MIATCUAT2 ALL TTAA00 KNHC DDHHMM HURRICANE IKE TROPICAL CYCLONE UPDATE NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL PM AST FRI SEP AT 6 PM AST UTC...THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A HURRICANE WATCH FOR THE SOUTHEASTERN BAHAMAS...INCLUDING THE ACKLINS... CROOKED ISLAND...THE INAGUAS...MAYAGUANA...AND THE RAGGED ISLANDS...AS WELL AS FOR THE TURKS AND CAICOS ISLANDS. $$ FORECASTER BLAKE/BEVEN

116 Seasonal Forecasting is more than this!