...HELENE BECOMES A CATEGORY 2 HURRICANE WITH SIGNIFICANT ADDITIONAL STRENGTHENING EXPECTED BEFORE LANDFALL IN FLORIDA... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... As of 7:00 AM CDT Thu Sep 26 the center of Helene was located near 24.5, -85.9 with movement NNE at 12 mph. The minimum central pressure was 960 mb with maximum sustained winds of about 100 mph.

Issued at 700 AM CDT Thu Sep 26 2024 000 WTNT34 KNHC 261139 TCPAT4 BULLETIN Hurricane Helene Intermediate Advisory Number 12A NWS National Hurricane Center Miami FL AL092024 700 AM CDT Thu Sep 26 2024 ...HELENE BECOMES A CATEGORY 2 HURRICANE WITH SIGNIFICANT ADDITIONAL STRENGTHENING EXPECTED BEFORE LANDFALL IN FLORIDA... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... SUMMARY OF 700 AM CDT...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...24.5N 85.9W ABOUT 320 MI...515 KM SW OF TAMPA FLORIDA ABOUT 365 MI...585 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Mexico Beach eastward and southward to Flamingo * Tampa Bay * Charlotte Harbor A Hurricane Warning is in effect for... * Anclote River to Mexico Beach A Hurricane Watch is in effect for... * Englewood to Anclote River, including Tampa Bay A Tropical Storm Warning is in effect for... * Florida Keys, including the Dry Tortugas * Flamingo to Anclote River, including Tampa Bay * West of Mexico Beach to the Okaloosa/Walton County Line * Flamingo northward to Little River Inlet * Lake Okeechobee * Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 700 AM CDT (1200 UTC), the center of Hurricane Helene was located near latitude 24.5 North, longitude 85.9 West. Helene is moving toward the north-northeast near 12 mph (19 km/h). This general motion is expected to continued with a significant increase in forward speed during the next 24 hours. On the forecast track, Helene will move across the eastern Gulf of Mexico today and cross the Florida Big Bend coast this evening or early Friday morning. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday. Maximum sustained winds have increased to near 100 mph (155 km/h) with higher gusts. Additional strengthening is forecast, and Helene is expected to be a major hurricane when it reaches the Florida Big Bend coast this evening. Weakening is expected after landfall, but Helene's fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians. Hurricane-force winds extend outward up to 60 miles (95 km) from the center and tropical-storm-force winds extend outward up to 345 miles (555 km). The Key West Naval Air Station recently reported sustained winds of 41 mph (66 km/h) and a wind gust of 55 mph (89 km/h). An observation in Sand Key recently reported sustained winds of 45 mph (72 km/h) and a gust to 58 mph (93 km/h). The estimated minimum central pressure based on data from the NOAA and Air Force Reserve Hurricane Hunter aircraft is 960 mb (28.35 inches). HAZARDS AFFECTING LAND ---------------------- Key Messages for Helene can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC and on the web at hurricanes.gov/text/MIATCDAT4.shtml STORM SURGE: The combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Carrabelle, FL to Suwannee River, FL...15-20 ft Apalachicola, FL to Carrabelle, FL...10-15 ft Suwannee River, FL to Chassahowitzka, FL...10-15 ft Chassahowitzka, FL to Anclote River, FL...8-12 ft Indian Pass, FL to Apalachicola, FL...6-10 ft Anclote River, FL to Middle of Longboat Key, FL...5-8 ft Tampa Bay...5-8 ft Middle of Longboat Key, FL to Englewood, FL...4-7 ft East of Mexico Beach, FL to Indian Pass, FL...3-5 ft Englewood, FL to Flamingo, FL...3-5 ft Charlotte Harbor...3-5 ft For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. Storm surge could raise water levels by as much as 2 to 4 feet above normal tide levels in areas of onshore winds along the southern coast of Pinar del Rio, Cuba, including the Isle of Youth. WIND: Hurricane conditions are expected within the U.S. hurricane warning area late today. Tropical storm conditions have already begun in the Florida Keys and portions of south Florida, and these conditions are expected to spread northward across the state and into Georgia and South Carolina through tonight. Tropical storm conditions are expected over portions of the warning area in western Cuba during the next few hours. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba, the Cayman Islands and the northeast Yucatan Peninsula, with isolated totals around 12 inches. This rainfall brings a risk of considerable flooding. Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches with isolated totals around 18 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous landslides are expected in steep terrain across the southern Appalachians. For a complete depiction of forecast rainfall associated with Hurricane Helene, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero. TORNADOES: The risk for several tornadoes will gradually increase today through tonight. The greatest threat is expected from parts of northern Florida into southeast Georgia, the Midlands and Low Country of South Carolina, and southern North Carolina. SURF: Swells generated by Helene will affect much of Florida and the coasts of Georgia and the Carolinas during the next couple of days. Swells will also continue across portions of Cuba and the Yucatan Peninsula through tonight. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 1000 AM CDT. $$ Forecaster Cangialosi

000
ABNT20 KNHC 261124
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Thu Sep 26 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Helene, located over the southeastern Gulf of Mexico and on Tropical
Storm Isaac, located over the central Subtropical Atlantic Ocean.

Eastern and Central Tropical Atlantic (AL98):
Shower and thunderstorm activity associated with an area of low
pressure located several hundred miles west of the Cabo Verde
Islands has become more organized during the past several hours.
Environmental conditions appear conducive for continued development
of this system, and a tropical depression could form as soon as
later today while it moves generally westward to west-northwestward
near 15 mph today and tomorrow. The system is then forecast to
slow down and turn northward late Friday and Saturday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

&&
Public Advisories on Tropical Storm Isaac are issued under WMO
header WTNT35 KNHC and under AWIPS header MIATCPAT5.
Forecast/Advisories on Tropical Storm Isaac are issued under WMO
header WTNT25 KNHC and under AWIPS header MIATCMAT5.

$$
Forecaster D. Zelinsky

Potential Storm Surge Flooding Map last updated Thu, 26 Sep 2024 09:50:28 GMT

Probabilistic Storm Surge Graphics last updated Thu, 26 Sep 2024 09:23:36 GMT

5-Day Uncertainty Track last updated Thu, 26 Sep 2024 08:57:49 GMT


Wind Speed Probabilities last updated Thu, 26 Sep 2024 08:57:49 GMT

Storm Surge Watch/Warning Map last updated Thu, 26 Sep 2024 08:53:53 GMT

Issued at 400 AM CDT Thu Sep 26 2024 000 WTNT44 KNHC 260852 TCDAT4 Hurricane Helene Discussion Number 12 NWS National Hurricane Center Miami FL AL092024 400 AM CDT Thu Sep 26 2024 Helene is sending some mixed structural signals this morning. On one side, an Air Force Reserve Hurricane Hunter aircraft reports that the central pressure has fallen to near 966 mb, and satellite imagery shows the eye is trying to clear out. On another side, the aircraft reported concentric eyewalls of 16 and 32 n mi diameter, with the maximum flight-level winds, 80 kt at 700 mb, occurring about 50 n mi southeast of the center likely in relation to the outer eyewall. Based on the central pressure fall and the available data, the initial intensity is increased to 80 kt. The hurricane is starting its expected turn toward the north-northeast, with the initial motion now 015/10. The hurricane should accelerate north-northeastward during the next 24 h or so in the flow between a ridge over the Atlantic and a deep-layer baroclinic trough/cut-off low over the Tennessee Valley. This motion should bring the center of Helene to the coast of the Florida Big Bend region Thursday evening or early Friday morning. After landfall, Helene should turn northward and northwestward around the northeast and north side of the Tennessee Valley system. After 48 h, what is left of Helene should make a cyclonic loop as it merges with the baroclinic system. The latest track guidance has nudged a little to the northeast, especially near 36 h, and the portion of the new forecast track over Georgia and Tennessee has been moved a bit to the east. Helene remains in an atmospheric and oceanic environment over the eastern Gulf of Mexico that is very conducive for strengthening, with the system forecast to traverse the Loop Current while it remains in a moist and low-shear environment. The main restraining factor on intensification is the current concentric eyewall status. All of the intensity guidance continues to forecast strengthening until landfall. Based on this, the new intensity forecast calls for Helen to become a major hurricane in about 12 h, and additional intensification is expected in the ensuing 6 h period or so before landfall. After landfall, Helene should weaken and undergo extratropical transition as it merges with the baroclinic system over the Tennessee Valley, and this is expected to be complete by about 36 h. The remnant extratropical low is forecast to dissipate after 72 h based on global model forecasts. Helene is forecast to be a large major hurricane when it reaches the Big Bend coast of Florida. As a result, storm surge, wind, and rainfall impacts will extend well away from the center and outside the forecast cone, particularly on the east side. In addition, the fast forward speed when Helene moves inland will result in a far inland penetration of strong winds over parts of the southeastern United States, including strong gusts over higher terrain of the southern Appalachians. Indeed, the GFS and ECMWF models suggest the possibility that the inner wind core may persist until the center reaches northern Georgia. A higher-than-normal gust factor is indicated in the official forecast while Helene is inland. KEY MESSAGES: 1. A catastrophic and deadly storm surge is likely along portions of the Florida Big Bend coast, where inundation could reach as high as 20 feet above ground level, along with destructive waves. There is also a danger of life-threatening storm surge along the remainder of the west coast of the Florida Peninsula. Residents in those areas should follow advice given by local officials and evacuate if told to do so. 2. Potentially catastrophic hurricane-force winds are expected within the eyewall of Helene when it makes landfall in the Florida Big Bend region later today. Preparations to protect life and property should be completed this morning before tropical storm conditions arrive. Damaging and life-threatening hurricane-force winds, especially in gusts, will penetrate well inland over portions of northern Florida and southern Georgia later today and tonight where Hurricane Warnings are in effect. Strong wind gusts are also likely farther north across portions of northern Georgia and the Carolinas, particularly over the higher terrain of the southern Appalachians. 3. Catastrophic and life-threatening flash and urban flooding, including numerous significant landslides, is expected across portions of the southern Appalachians through Friday. Considerable to locally catastrophic flash and urban flooding is likely for northwestern and northern Florida and the Southeast through Friday. Widespread significant river flooding and isolated major river flooding are likely. 4. Tropical storm conditions are expected over portions of western Cuba within the Tropical Storm Warning area. Hurricane Helene will bring heavy rain to portions of the western Caribbean with potentially significant flooding across western Cuba and the northeastern Yucatan Peninsula through this morning. FORECAST POSITIONS AND MAX WINDS INIT 26/0900Z 24.2N 86.2W 80 KT 90 MPH 12H 26/1800Z 26.8N 85.2W 100 KT 115 MPH 24H 27/0600Z 31.6N 84.0W 75 KT 85 MPH...INLAND 36H 27/1800Z 36.1N 84.9W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 28/0600Z 37.0N 87.8W 25 KT 30 MPH...POST-TROP/EXTRATROP 60H 28/1800Z 36.3N 87.8W 20 KT 25 MPH...POST-TROP/EXTRATROP 72H 29/0600Z 36.3N 86.7W 20 KT 25 MPH...POST-TROP/EXTRATROP 96H 30/0600Z...DISSIPATED $$ Forecaster Beven

Issued at 0900 UTC THU SEP 26 2024 000 FONT14 KNHC 260852 PWSAT4 HURRICANE HELENE WIND SPEED PROBABILITIES NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0900 UTC THU SEP 26 2024 AT 0900Z THE CENTER OF HURRICANE HELENE WAS LOCATED NEAR LATITUDE 24.2 NORTH...LONGITUDE 86.2 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 80 KTS...90 MPH...150 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z THU AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z THU 18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON PERIODS TO TO TO TO TO TO TO 18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON 06Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT FAYETTEVILLE 34 X 1( 1) 2( 3) X( 3) X( 3) X( 3) X( 3) CHARLOTTE NC 34 X 4( 4) 3( 7) X( 7) X( 7) X( 7) X( 7) BALD HEAD ISL 34 X 1( 1) 2( 3) X( 3) X( 3) X( 3) X( 3) FLORENCE SC 34 X 5( 5) 1( 6) X( 6) X( 6) X( 6) X( 6) COLUMBIA SC 34 X 10(10) 6(16) X(16) X(16) X(16) X(16) LITTLE RIVER 34 X 6( 6) 4(10) X(10) X(10) X(10) X(10) MYRTLE BEACH 34 X 9( 9) 3(12) X(12) X(12) X(12) X(12) GEORGETOWN SC 34 X 5( 5) 1( 6) X( 6) X( 6) X( 6) X( 6) CHARLESTON SC 34 X 25(25) 4(29) X(29) X(29) X(29) X(29) BEAUFORT MCAS 34 X 41(41) 2(43) X(43) X(43) X(43) X(43) ATLANTA GA 34 X 21(21) 52(73) X(73) X(73) X(73) X(73) AUGUSTA GA 34 X 38(38) 16(54) X(54) X(54) X(54) X(54) SAVANNAH GA 34 X 47(47) 1(48) X(48) X(48) X(48) X(48) KINGS BAY GA 34 2 64(66) X(66) X(66) X(66) X(66) X(66) KINGS BAY GA 50 X 7( 7) X( 7) X( 7) X( 7) X( 7) X( 7) WAYCROSS GA 34 1 91(92) X(92) X(92) X(92) X(92) X(92) WAYCROSS GA 50 X 11(11) 1(12) X(12) X(12) X(12) X(12) WAYCROSS GA 64 X 2( 2) X( 2) X( 2) X( 2) X( 2) X( 2) MAYPORT NS FL 34 5 59(64) X(64) X(64) X(64) X(64) X(64) MAYPORT NS FL 50 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) JACKSONVILLE 34 4 69(73) X(73) X(73) X(73) X(73) X(73) GAINESVILLE FL 34 15 79(94) X(94) X(94) X(94) X(94) X(94) GAINESVILLE FL 50 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) GAINESVILLE FL 64 X 1( 1) X( 1) X( 1) X( 1) X( 1) X( 1) DAYTONA BEACH 34 7 40(47) X(47) X(47) X(47) X(47) X(47) THE VILLAGES 34 30 56(86) X(86) X(86) X(86) X(86) X(86) ORLANDO FL 34 20 36(56) X(56) X(56) X(56) X(56) X(56) COCOA BEACH FL 34 16 26(42) X(42) X(42) X(42) X(42) X(42) PATRICK AFB 34 16 26(42) X(42) X(42) X(42) X(42) X(42) FT PIERCE FL 34 15 18(33) X(33) X(33) X(33) X(33) X(33) W PALM BEACH 34 13 11(24) X(24) X(24) X(24) X(24) X(24) FT LAUDERDALE 34 13 6(19) X(19) X(19) X(19) X(19) X(19) MIAMI FL 34 7 2( 9) X( 9) X( 9) X( 9) X( 9) X( 9) HOMESTEAD ARB 34 8 1( 9) X( 9) X( 9) X( 9) X( 9) X( 9) MARATHON FL 34 24 3(27) X(27) X(27) X(27) X(27) X(27) KEY WEST FL 34 46 2(48) X(48) X(48) X(48) X(48) X(48) NAPLES FL 34 62 4(66) X(66) X(66) X(66) X(66) X(66) FT MYERS FL 34 77 2(79) X(79) X(79) X(79) X(79) X(79) VENICE FL 34 79 5(84) X(84) X(84) X(84) X(84) X(84) VENICE FL 50 5 3( 8) X( 8) X( 8) X( 8) X( 8) X( 8) TAMPA FL 34 71 16(87) X(87) X(87) X(87) X(87) X(87) TAMPA FL 50 3 8(11) X(11) X(11) X(11) X(11) X(11) TAMPA FL 64 X 1( 1) X( 1) X( 1) X( 1) X( 1) X( 1) CEDAR KEY FL 34 56 40(96) X(96) X(96) X(96) X(96) X(96) CEDAR KEY FL 50 1 37(38) X(38) X(38) X(38) X(38) X(38) CEDAR KEY FL 64 X 9( 9) X( 9) X( 9) X( 9) X( 9) X( 9) TALLAHASSEE FL 34 7 92(99) X(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 50 X 78(78) X(78) X(78) X(78) X(78) X(78) TALLAHASSEE FL 64 X 26(26) 1(27) X(27) X(27) X(27) X(27) ST MARKS FL 34 12 88(99) X(99) X(99) X(99) X(99) X(99) ST MARKS FL 50 X 84(84) X(84) X(84) X(84) X(84) X(84) ST MARKS FL 64 X 39(39) X(39) X(39) X(39) X(39) X(39) APALACHICOLA 34 39 57(96) X(96) X(96) X(96) X(96) X(96) APALACHICOLA 50 2 76(78) X(78) X(78) X(78) X(78) X(78) APALACHICOLA 64 X 36(36) X(36) X(36) X(36) X(36) X(36) GFMX 290N 850W 34 69 29(98) X(98) X(98) X(98) X(98) X(98) GFMX 290N 850W 50 5 84(89) X(89) X(89) X(89) X(89) X(89) GFMX 290N 850W 64 X 55(55) X(55) X(55) X(55) X(55) X(55) PANAMA CITY FL 34 20 58(78) X(78) X(78) X(78) X(78) X(78) PANAMA CITY FL 50 X 31(31) X(31) X(31) X(31) X(31) X(31) PANAMA CITY FL 64 X 5( 5) X( 5) X( 5) X( 5) X( 5) X( 5) DESTIN EXEC AP 34 4 20(24) X(24) X(24) X(24) X(24) X(24) ALBANY GA 34 2 93(95) X(95) X(95) X(95) X(95) X(95) ALBANY GA 50 X 53(53) 2(55) X(55) X(55) X(55) X(55) ALBANY GA 64 X 9( 9) 1(10) X(10) X(10) X(10) X(10) COLUMBUS GA 34 X 54(54) 13(67) X(67) X(67) X(67) X(67) COLUMBUS GA 50 X 2( 2) 6( 8) X( 8) X( 8) X( 8) X( 8) MACON GA 34 X 78(78) 15(93) X(93) X(93) X(93) X(93) MACON GA 50 X 7( 7) 20(27) X(27) X(27) X(27) X(27) DOTHAN AL 34 4 62(66) 1(67) X(67) X(67) X(67) X(67) DOTHAN AL 50 X 9( 9) X( 9) X( 9) X( 9) X( 9) X( 9) BIRMINGHAM AL 34 X 4( 4) 1( 5) 1( 6) X( 6) X( 6) X( 6) MONTGOMERY AL 34 X 9( 9) 2(11) X(11) X(11) X(11) X(11) WHITING FLD FL 34 3 6( 9) X( 9) X( 9) X( 9) X( 9) X( 9) PENSACOLA FL 34 3 5( 8) X( 8) X( 8) X( 8) X( 8) X( 8) GFMX 290N 870W 34 20 14(34) X(34) X(34) X(34) X(34) X(34) GFMX 290N 870W 50 2 3( 5) X( 5) X( 5) X( 5) X( 5) X( 5) MOBILE AL 34 2 4( 6) X( 6) X( 6) X( 6) X( 6) X( 6) GULFPORT MS 34 2 3( 5) X( 5) X( 5) X( 5) X( 5) X( 5) STENNIS MS 34 1 3( 4) X( 4) X( 4) X( 4) X( 4) X( 4) BURAS LA 34 2 3( 5) X( 5) X( 5) X( 5) X( 5) X( 5) GFMX 280N 890W 34 5 3( 8) X( 8) X( 8) X( 8) X( 8) X( 8) CP SAN ANTONIO 34 99 X(99) X(99) X(99) X(99) X(99) X(99) HAVANA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ISLE OF PINES 34 99 X(99) X(99) X(99) X(99) X(99) X(99) $$ FORECASTER BEVEN

...HELENE STRENGTHENING AND EXPECTED TO BRING CATASTROPHIC WINDS AND STORM SURGE TO THE NORTHEASTERN GULF COAST... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... As of 4:00 AM CDT Thu Sep 26 the center of Helene was located near 24.2, -86.2 with movement NNE at 12 mph. The minimum central pressure was 966 mb with maximum sustained winds of about 90 mph.

Issued at 400 AM CDT Thu Sep 26 2024 000 WTNT34 KNHC 260851 TCPAT4 BULLETIN Hurricane Helene Advisory Number 12 NWS National Hurricane Center Miami FL AL092024 400 AM CDT Thu Sep 26 2024 ...HELENE STRENGTHENING AND EXPECTED TO BRING CATASTROPHIC WINDS AND STORM SURGE TO THE NORTHEASTERN GULF COAST... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...24.2N 86.2W ABOUT 350 MI...560 KM SW OF TAMPA FLORIDA ABOUT 385 MI...625 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...966 MB...28.53 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Mexico Beach eastward and southward to Flamingo * Tampa Bay * Charlotte Harbor A Hurricane Warning is in effect for... * Anclote River to Mexico Beach A Hurricane Watch is in effect for... * Englewood to Anclote River, including Tampa Bay A Tropical Storm Warning is in effect for... * Florida Keys, including the Dry Tortugas * Flamingo to Anclote River, including Tampa Bay * West of Mexico Beach to the Okaloosa/Walton County Line * Flamingo northward to Little River Inlet * Lake Okeechobee * Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within the next 36 hours. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 400 AM CDT (0900 UTC), the center of Hurricane Helene was located near latitude 24.2 North, longitude 86.2 West. Helene is moving toward the north-northeast near 12 mph (19 km/h). This general motion is expected to continued with a significant increase in forward speed during the next 24 hours. On the forecast track, Helene will move across the eastern Gulf of Mexico today and cross the Florida Big Bend coast this evening or early Friday morning. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday. Maximum sustained winds have increased to near 90 mph (150 km/h) with higher gusts. Strengthening is forecast, and Helene is expected to be a major hurricane when it reaches the Florida Big Bend coast this evening. Weakening is expected after landfall, but Helene's fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians. Hurricane-force winds extend outward up to 60 miles (95 km) from the center and tropical-storm-force winds extend outward up to 345 miles (555 km). The Key West Naval Air Station recently reported sustained winds of 41 mph (66 km/h) and a wind gust of 64 mph (103 km/h). The estimated minimum central pressure based on Air Force Reserve Hurricane Hunter aircraft data is 966 mb (28.53 inches). HAZARDS AFFECTING LAND ---------------------- Key Messages for Helene can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC and on the web at hurricanes.gov/text/MIATCDAT4.shtml STORM SURGE: The combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Carrabelle, FL to Suwannee River, FL...15-20 ft Apalachicola, FL to Carrabelle, FL...10-15 ft Suwannee River, FL to Chassahowitzka, FL...10-15 ft Chassahowitzka, FL to Anclote River, FL...8-12 ft Indian Pass, FL to Apalachicola, FL...6-10 ft Anclote River, FL to Middle of Longboat Key, FL...5-8 ft Tampa Bay...5-8 ft Middle of Longboat Key, FL to Englewood, FL...4-7 ft East of Mexico Beach, FL to Indian Pass, FL...3-5 ft Englewood, FL to Flamingo, FL...3-5 ft Charlotte Harbor...3-5 ft For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. Storm surge could raise water levels by as much as 2 to 4 feet above normal tide levels in areas of onshore winds along the southern coast of Pinar del Rio, Cuba, including the Isle of Youth. WIND: Hurricane conditions are expected within the U.S. hurricane warning area late today, with tropical storm conditions beginning this morning. Tropical storm conditions are spreading across the Florida Keys at this time, and they are expected to spread northward across the rest of Florida, Georgia, and South Carolina through tonight. Tropical storm conditions are expected over portions of the warning area in western Cuba during the next few hours. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba, the Cayman Islands and the northeast Yucatan Peninsula, with isolated totals around 12 inches. This rainfall brings a risk of considerable flooding. Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches with isolated totals around 18 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous landslides are expected in steep terrain across the southern Appalachians. For a complete depiction of forecast rainfall associated with Hurricane Helene, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero. TORNADOES: The risk for several tornadoes will gradually increase today through tonight. The greatest threat is expected from parts of northern Florida into southeast Georgia, the Midlands and Low Country of South Carolina, and southern North Carolina. SURF: Swells generated by Helene will affect the southern coast of Cuba and the Yucatan Peninsula of Mexico during the next couple of days. Swells will spread northward toward the west coast of Florida and the northeastern Gulf Coast today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 700 AM CDT. Next complete advisory at 1000 AM CDT. $$ Forecaster Beven

Issued at 0900 UTC THU SEP 26 2024 000 WTNT24 KNHC 260851 TCMAT4 HURRICANE HELENE FORECAST/ADVISORY NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0900 UTC THU SEP 26 2024 HURRICANE CENTER LOCATED NEAR 24.2N 86.2W AT 26/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 15 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 966 MB EYE DIAMETER 25 NM MAX SUSTAINED WINDS 80 KT WITH GUSTS TO 100 KT. 64 KT....... 50NE 50SE 30SW 0NW. 50 KT....... 80NE 80SE 40SW 40NW. 34 KT.......250NE 300SE 100SW 120NW. 12 FT SEAS..240NE 270SE 150SW 180NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 24.2N 86.2W AT 26/0900Z AT 26/0600Z CENTER WAS LOCATED NEAR 23.6N 86.5W FORECAST VALID 26/1800Z 26.8N 85.2W MAX WIND 100 KT...GUSTS 120 KT. 64 KT... 50NE 50SE 30SW 20NW. 50 KT... 80NE 90SE 50SW 40NW. 34 KT...270NE 270SE 120SW 120NW. FORECAST VALID 27/0600Z 31.6N 84.0W...INLAND MAX WIND 75 KT...GUSTS 95 KT. 64 KT... 30NE 40SE 20SW 0NW. 50 KT... 60NE 80SE 50SW 40NW. 34 KT...270NE 270SE 140SW 70NW. FORECAST VALID 27/1800Z 36.1N 84.9W...POST-TROP/EXTRATROP MAX WIND 30 KT...GUSTS 50 KT. FORECAST VALID 28/0600Z 37.0N 87.8W...POST-TROP/EXTRATROP MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 28/1800Z 36.3N 87.8W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 29/0600Z 36.3N 86.7W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 30/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.2N 86.2W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 26/1200Z NEXT ADVISORY AT 26/1500Z $$ FORECASTER BEVEN

5-Day Uncertainty Track last updated Thu, 26 Sep 2024 08:43:02 GMT


Wind Speed Probabilities last updated Thu, 26 Sep 2024 09:29:24 GMT

Issued at 500 AM AST Thu Sep 26 2024 000 WTNT45 KNHC 260840 TCDAT5 Tropical Storm Isaac Discussion Number 2 NWS National Hurricane Center Miami FL AL102024 500 AM AST Thu Sep 26 2024 Isaac's structure on satellite looks fairly healthy for a high-latitude tropical cyclone. There are plenty of curved banding features rotating around the estimated center on IR satellite, matched by a recent AMSR2 microwave pass also showing convective banding. While the cloud top temperatures are not that cold, only -50 to -60 C, that is rather typical for a tropical cyclone along the axis of an upper-level trough with a depressed tropopause. Based on the earlier scatterometer wind data, plus a DMINT estimate from the AMSR2 pass of 46 kt, the initial intensity is held at 45 kt this advisory. The tropical storm is continuing eastward this morning at 90/10 kt. This general motion, albeit with a gradual turn more east-northeastward is expected over the next several days as Isaac slowly accelerates under the influence of mid-level ridging to the southeast of the storm. The track guidance is in pretty good agreement in the short-term. However, differences primarily in the along-track direction begin to be evident beyond 48 h, which could ultimately play a role in more notable across-track differences shown between the GFS and ECMWF solutions by early next week. For now, the NHC track forecast is very similar to the previous track forecast, and favors a solution very similar to the HFIP corrected consensus approach (HCCA) and ECMWF track. Given the storm's healthy current structure, there is an opportunity for it to intensify over the next couple of days. During this time span, sea-surface temperatures (SSTs) hover between 26-27 C, colder than normal upper-level temperatures should aid tropospheric instability, and vertical wind shear is forecast to remain in the 15-20 kt range, in the same direction as the storm motion. The simulated IR imagery from the latest ECMWF and GFS runs also show Isaac attempting to clear out an eye occasionally in the 36-60 h period. These signals suggest that Isaac could become a hurricane, and that is now explicitly reflected in the latest NHC forecast, which is very close to the latest HCCA consensus aid. After 60 h, shear increases markedly as SSTs also decrease, which should lead to weakening, and Isaac is forecast to become post-tropical sometime near the end of the forecast as it passes by to the north of the Azores. FORECAST POSITIONS AND MAX WINDS INIT 26/0900Z 37.1N 52.8W 45 KT 50 MPH 12H 26/1800Z 37.2N 50.9W 50 KT 60 MPH 24H 27/0600Z 37.6N 48.1W 55 KT 65 MPH 36H 27/1800Z 38.3N 44.9W 60 KT 70 MPH 48H 28/0600Z 39.4N 41.2W 65 KT 75 MPH 60H 28/1800Z 40.5N 37.9W 65 KT 75 MPH 72H 29/0600Z 41.8N 34.0W 60 KT 70 MPH 96H 30/0600Z 43.0N 27.2W 55 KT 65 MPH 120H 01/0600Z 43.4N 19.4W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin

Issued at 0900 UTC THU SEP 26 2024 000 FONT15 KNHC 260839 PWSAT5 TROPICAL STORM ISAAC WIND SPEED PROBABILITIES NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC THU SEP 26 2024 AT 0900Z THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 37.1 NORTH...LONGITUDE 52.8 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 45 KTS...50 MPH...85 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z THU AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z THU 18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON PERIODS TO TO TO TO TO TO TO 18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON 06Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X X( X) X( X) X( X) 17(17) 7(24) 1(25) SANTA CRUZ AZO 50 X X( X) X( X) X( X) 1( 1) 2( 3) 1( 4) PONTA DELGADA 34 X X( X) X( X) X( X) X( X) 3( 3) 1( 4) $$ FORECASTER PAPIN

...ISAAC CONTINUES EASTWARD AND COULD BECOME A HURRICANE IN A COUPLE OF DAYS... As of 5:00 AM AST Thu Sep 26 the center of Isaac was located near 37.1, -52.8 with movement E at 12 mph. The minimum central pressure was 997 mb with maximum sustained winds of about 50 mph.

Issued at 500 AM AST Thu Sep 26 2024 000 WTNT35 KNHC 260839 TCPAT5 BULLETIN Tropical Storm Isaac Advisory Number 2 NWS National Hurricane Center Miami FL AL102024 500 AM AST Thu Sep 26 2024 ...ISAAC CONTINUES EASTWARD AND COULD BECOME A HURRICANE IN A COUPLE OF DAYS... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...37.1N 52.8W ABOUT 1410 MI...2270 KM W OF THE AZORES ABOUT 755 MI...1220 KM ENE OF BERMUDA MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...E OR 90 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 500 AM AST (0900 UTC), the center of Tropical Storm Isaac was located near latitude 37.1 North, longitude 52.8 West. Isaac is moving toward the east near 12 mph (19 km/h) and a general eastward to east-northeastward motion is expected to continue for the next several days. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Some strengthening is forecast during the next 48 hours and Isaac could be become a hurricane by Friday over the open Subtropical Atlantic. Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 997 mb (29.44 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Isaac and a large wind fetch from a deep-layer trough are affecting portions of the coast of Bermuda and could spread into the Azores by this weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Papin

Issued at 0900 UTC THU SEP 26 2024 000 WTNT25 KNHC 260839 TCMAT5 TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC THU SEP 26 2024 TROPICAL STORM CENTER LOCATED NEAR 37.1N 52.8W AT 26/0900Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE EAST OR 90 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT....... 60NE 60SE 60SW 60NW. 12 FT SEAS.. 0NE 120SE 120SW 120NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 37.1N 52.8W AT 26/0900Z AT 26/0600Z CENTER WAS LOCATED NEAR 37.1N 53.4W FORECAST VALID 26/1800Z 37.2N 50.9W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 0NE 30SE 0SW 0NW. 34 KT... 40NE 50SE 50SW 40NW. FORECAST VALID 27/0600Z 37.6N 48.1W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 0NE 40SE 30SW 0NW. 34 KT... 60NE 70SE 60SW 50NW. FORECAST VALID 27/1800Z 38.3N 44.9W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 0NE 40SE 40SW 30NW. 34 KT... 60NE 100SE 60SW 50NW. FORECAST VALID 28/0600Z 39.4N 41.2W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 0NE 25SE 0SW 0NW. 50 KT... 40NE 50SE 40SW 40NW. 34 KT... 90NE 120SE 90SW 80NW. FORECAST VALID 28/1800Z 40.5N 37.9W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 35NE 50SE 45SW 35NW. 34 KT...120NE 130SE 100SW 110NW. FORECAST VALID 29/0600Z 41.8N 34.0W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 40NE 60SE 50SW 40NW. 34 KT...140NE 120SE 110SW 120NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 30/0600Z 43.0N 27.2W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 0NE 60SE 50SW 0NW. 34 KT...140NE 110SE 100SW 140NW. OUTLOOK VALID 01/0600Z 43.4N 19.4W...POST-TROP/EXTRATROP MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 0NE 40SE 40SW 0NW. 34 KT...110NE 90SE 90SW 110NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.1N 52.8W NEXT ADVISORY AT 26/1500Z $$ FORECASTER PAPIN

...HELENE MOVING NORTHWARD AND EXPECTED TO BRING CATASTROPHIC WINDS AND STORM SURGE TO THE NORTHEASTERN GULF COAST... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... As of 1:00 AM CDT Thu Sep 26 the center of Helene was located near 23.7, -86.5 with movement N at 12 mph. The minimum central pressure was 971 mb with maximum sustained winds of about 85 mph.

Issued at 100 AM CDT Thu Sep 26 2024 000 WTNT34 KNHC 260556 TCPAT4 BULLETIN Hurricane Helene Intermediate Advisory Number 11A NWS National Hurricane Center Miami FL AL092024 100 AM CDT Thu Sep 26 2024 ...HELENE MOVING NORTHWARD AND EXPECTED TO BRING CATASTROPHIC WINDS AND STORM SURGE TO THE NORTHEASTERN GULF COAST... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...23.7N 86.5W ABOUT 385 MI...620 KM SW OF TAMPA FLORIDA ABOUT 425 MI...680 KM SSW OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H PRESENT MOVEMENT...N OR 5 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...971 MB...28.67 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Mexico Beach eastward and southward to Flamingo * Tampa Bay * Charlotte Harbor A Hurricane Warning is in effect for... * Anclote River to Mexico Beach A Hurricane Watch is in effect for... * Englewood to Anclote River, including Tampa Bay A Tropical Storm Warning is in effect for... * Florida Keys, including the Dry Tortugas * Flamingo to Anclote River, including Tampa Bay * West of Mexico Beach to the Okaloosa/Walton County Line * Flamingo northward to Little River Inlet * Lake Okeechobee * Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within the next 36 hours. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 100 AM CDT (0600 UTC), the center of Hurricane Helene was located near latitude 23.7 North, longitude 86.5 West. Helene is moving toward the north near 12 mph (19 km/h). A northward or north-northeastward motion at a faster forward speed is expected during the next 36 hours. On the forecast track, Helene will move across the eastern Gulf of Mexico today and cross the Florida Big Bend coast this evening. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday. Maximum sustained winds are near 85 mph (140 km/h) with higher gusts. Strengthening is forecast, and Helene is expected to be a major hurricane when it reaches the Florida Big Bend coast this evening. Weakening is expected after landfall, but Helene's fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians. Hurricane-force winds extend outward up to 35 miles (55 km) from the center and tropical-storm-force winds extend outward up to 345 miles (555 km). The NOAA automated station at Sand Key, Florida recently reported sustained winds of 45 mph (72 km/h). The estimated minimum central pressure from Air Force Reserve Hurricane Hunter aircraft data is 971 mb (28.67 inches). HAZARDS AFFECTING LAND ---------------------- Key Messages for Helene can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC and on the web at hurricanes.gov/text/MIATCDAT4.shtml STORM SURGE: The combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Carrabelle, FL to Suwannee River, FL...15-20 ft Apalachicola, FL to Carrabelle, FL...10-15 ft Suwannee River, FL to Chassahowitzka, FL...10-15 ft Chassahowitzka, FL to Anclote River, FL...8-12 ft Indian Pass, FL to Apalachicola, FL...6-10 ft Anclote River, FL to Middle of Longboat Key, FL...5-8 ft Tampa Bay...5-8 ft Middle of Longboat Key, FL to Englewood, FL...4-7 ft East of Mexico Beach, FL to Indian Pass, FL...3-5 ft Englewood, FL to Flamingo, FL...3-5 ft Charlotte Harbor...3-5 ft For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. Storm surge could raise water levels by as much as 2 to 4 feet above normal tide levels in areas of onshore winds along the southern coast of Pinar del Rio, Cuba, including the Isle of Youth. WIND: Hurricane conditions are expected within the U.S. hurricane warning area late today, with tropical storm conditions beginning this morning. Tropical storm conditions are expected in southern Florida this morning and will spread northward across the rest of Florida, Georgia, and South Carolina through tonight. Tropical storm conditions are expected over portions of the warning area in western Cuba during the next several hours. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba, the Cayman Islands and the northeast Yucatan Peninsula, with isolated totals around 12 inches. This rainfall brings a risk of considerable flooding. Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches with isolated totals around 18 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous landslides are expected in steep terrain across the southern Appalachians. For a complete depiction of forecast rainfall associated with Hurricane Helene, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero. TORNADOES: A tornado or two may occur this morning over parts of Florida. The risk for tornadoes will increase later today, expanding northward across Florida into parts of Georgia and South Carolina. SURF: Swells generated by Helene will affect the southern coast of Cuba and the Yucatan Peninsula of Mexico during the next couple of days. Swells will spread northward toward the west coast of Florida and the northeastern Gulf Coast today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 400 AM CDT. $$ Forecaster Beven