Storm Surge Watch/Warning Map last updated Thu, 26 Sep 2024 20:44:30 GMT

...HELENE IS A VERY DANGEROUS AND LARGE MAJOR HURRICANE... ...DAMAGING HURRICANE WINDS AND CATASTROPHIC STORM SURGE EXPECTED TO BEGIN IN THE FLORIDA BIG BEND THIS EVENING... As of 5:00 PM EDT Thu Sep 26 the center of Helene was located near 27.9, -84.6 with movement NNE at 23 mph. The minimum central pressure was 951 mb with maximum sustained winds of about 125 mph.

Issued at 400 PM EDT Thu Sep 26 2024 000 WTNT64 KNHC 261955 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 400 PM EDT Thu Sep 26 2024 ...HELENE ACCELERATING TOWARD THE FLORIDA BIG BEND... ...TROPICAL STORM CONDITIONS OCCURING ACROSS MOST OF THE WEST COAST OF FLORIDA... Data from an Air Force Hurricane Hunter aircraft indicate that the minimum pressure of Helene has decreased to 951 mb (28.08 inches). A Weatherflow station at Egmont Channel at the entrance to Tampa Bay recently measured a sustained wind of 54 mph (87 km/h) and a gust to 68 mph (109 km/h). The Sarasota-Bradenton International Airport recently measured a sustained wind of 43 mph (69 km/h) and a gust to 63 mph (101 km/h). SUMMARY OF 400 PM EDT...2000 UTC...INFORMATION ---------------------------------------------- LOCATION...27.3N 84.7W ABOUT 145 MI...235 KM WSW OF TAMPA FLORIDA ABOUT 165 MI...265 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H PRESENT MOVEMENT...NNE OR 25 DEGREES AT 21 MPH...33 KM/H MINIMUM CENTRAL PRESSURE...951 MB...28.08 INCHES $$ Forecaster D. Zelinsky

...STORM SURGE AND WINDS INCREASING ALONG THE FLORIDA WEST COAST... ...300 PM EDT POSITION UPDATE... As of 3:00 PM EDT Thu Sep 26 the center of Helene was located near 26.9, -84.8 with movement NNE at 20 mph. The minimum central pressure was 959 mb with maximum sustained winds of about 120 mph.

Issued at 300 PM EDT Thu Sep 26 2024 000 WTNT64 KNHC 261856 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 300 PM EDT Thu Sep 26 2024 ...STORM SURGE AND WINDS INCREASING ALONG THE FLORIDA WEST COAST... ...300 PM EDT POSITION UPDATE... A Weatherflow station at Egmont Channel at the entrance to Tampa Bay recently measured a sustained wind of 50 mph (80 km/h) and a gust to 62 mph (100 km/h). SUMMARY OF 300 PM EDT...1900 UTC...INFORMATION ---------------------------------------------- LOCATION...26.9N 84.8W ABOUT 160 MI...255 KM WSW OF TAMPA FLORIDA ABOUT 195 MI...315 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H PRESENT MOVEMENT...NNE OR 25 DEGREES AT 20 MPH...31 KM/H MINIMUM CENTRAL PRESSURE...959 MB...28.32 INCHES $$ Forecaster Berg

Issued at 100 PM CDT Thu Sep 26 2024 000 WTNT34 KNHC 261747 TCPAT4 BULLETIN Hurricane Helene Intermediate Advisory Number 13A NWS National Hurricane Center Miami FL AL092024 100 PM CDT Thu Sep 26 2024 ...HELENE ALMOST A MAJOR HURRICANE WITH ADDITIONAL STRENGTHENING FORECAST BEFORE LANDFALL IN THE FLORIDA BIG BEND... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...26.4N 85.0W ABOUT 195 MI...315 KM SW OF TAMPA FLORIDA ABOUT 230 MI...365 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H PRESENT MOVEMENT...NNE OR 25 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...959 MB...28.32 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of Cuba has discontinued the tropical storm warning for the island. 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 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 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 100 PM CDT (1800 UTC), the center of Hurricane Helene was located near latitude 26.4 North, longitude 85.0 West. Helene is moving toward the north-northeast near 16 mph (26 km/h). A significant increase in forward speed is expected during the next 24 hours. On the forecast track, Helene will make landfall in the Florida Big Bend region this evening. 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 110 mph (175 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. Helene is a very large hurricane. 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). A weather station in Tarpon Point recently reported a sustained wind of 41 mph (67 km/h) with a gust to 54 mph (87 km/h). The minimum central pressure based on data from the Air Force Hurricane Hunters is 959 mb (28.32 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 The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. 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. WIND: Hurricane conditions are expected within the U.S. hurricane warning area late today. Tropical storm conditions have occurring in the Florida Keys and portions of southern and southwestern Florida, and these conditions are expected to spread northward across the tropical storm warning areas in the southeastern U.S. through early Friday. Strong, damaging winds, especially in gusts, will likely penetrate as far inland as the higher terrain of the southern Appalachians. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba. 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 20 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous significant 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. For a list of rainfall observations (and wind reports) associated this storm, see the companion storm summary at WBCSCCNS4 with the WMO header ACUS44 KWBC or at the following link: www.wpc.ncep.noaa.gov/discussions/nfdscc4.html. 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 400 PM CDT. Hourly position and intensity information will be provided in Tropical Cyclone Updates beginning at 300 PM EDT/200 PM CDT. $$ Forecaster Cangialosi

000
ABNT20 KNHC 261739
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM 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 eastern Gulf of Mexico and on Tropical
Storm Isaac, located over the central Subtropical Atlantic Ocean.

Eastern and Central Tropical Atlantic (AL98):
Showers and thunderstorms associated with an area of low pressure
located several hundred miles west of the Cabo Verde Islands
continue to show signs of organization. Recent satellite imagery
suggests the system does not yet have a well-defined surface
circulation. However, environmental conditions are expected to be
conducive for further development. A tropical depression is
expected to form later today or tomorrow while the disturbance
moves generally westward to west-northwestward at 10 to 15 mph. The
system is then forecast to slow down and turn northward late Friday
and Saturday.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

Western Caribbean:
An area of low pressure could form over the western Caribbean by the
middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter, while the system moves
generally northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 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/Bookbinder

Potential Storm Surge Flooding Map last updated Thu, 26 Sep 2024 15:54:26 GMT

Probabilistic Storm Surge Graphics last updated Thu, 26 Sep 2024 15:40:02 GMT

5-Day Uncertainty Track last updated Thu, 26 Sep 2024 14:56:01 GMT


Wind Speed Probabilities last updated Thu, 26 Sep 2024 15:23:16 GMT

Issued at 1000 AM CDT Thu Sep 26 2024 020 WTNT44 KNHC 261454 TCDAT4 Hurricane Helene Discussion Number 13 NWS National Hurricane Center Miami FL AL092024 1000 AM CDT Thu Sep 26 2024 Helene is gaining strength as it approaches the Florida Big Bend. A large eye has become apparent in satellite images, and that feature has been gradually clearing out over the past few hours. Convective banding is wrapping around the eye, and recent microwave images and reports from the NOAA and Air Force Hurricane Hunter aircraft indicate than an eyewall is almost completely closed. The minimum pressure has been dropping steadily to near 960 mb, and based on the aircraft flight-level wind data, the initial intensity is estimated to have increased to 90 kt. There have been several reports of tropical-storm-force winds occurring in portions of South Florida and the Florida Keys during the past few hours. The large hurricane is picking up speed and has turned slightly to the north-northeast. The latest initial motion is 025/12 kt. A notably faster north-northeastward motion is expected through landfall, which is expected to occur in the Florida Big Bend region this evening. After Helene moves inland, it is forecast to track over Georgia and then slow down or stall over the Tennessee Valley when it merges with a mid- to upper-level low pressure system. Only minor changes were made to the previous NHC track forecast. Significant intensification is expected until Helene reaches the coast since the overall atmospheric and oceanic conditions will remain conducive. The amount of strengthening will likely depend on how much the inner core can contract and consolidate. The HWRF and HMON models show significant strengthening to category 4 status, while most of the other models are a little lower. The main message is that Helene will likely make landfall as a large major hurricane in the Florida Big Bend this evening, and all preparations in the hurricane warning area should be rushed to completion. It should also be re-emphasized that Helene is a very large hurricane. In fact, comparing the system with previous hurricanes in the Gulf of Mexico over the past couple of decades, Helene is at the upper bound in terms of size. As a result, storm surge, wind, and rainfall impacts will extend far away from the center and well 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. Accordingly, 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 this evening. Preparations to protect life and property should be rushed to completion. 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. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 25.5N 85.5W 90 KT 105 MPH 12H 27/0000Z 28.8N 84.3W 105 KT 120 MPH 24H 27/1200Z 33.9N 84.5W 55 KT 65 MPH...INLAND 36H 28/0000Z 36.4N 86.6W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 28/1200Z 36.5N 87.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 60H 29/0000Z 36.3N 87.6W 20 KT 25 MPH...POST-TROP/EXTRATROP 72H 29/1200Z 36.2N 87.2W 20 KT 25 MPH...POST-TROP/EXTRATROP 96H 30/1200Z...DISSIPATED $$ Forecaster Cangialosi

...HELENE STRENGTHENING AND EXPECTED TO MAKE LANDFALL IN THE FLORIDA BIG BEND THIS EVENING AS A MAJOR HURRICANE... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... As of 10:00 AM CDT Thu Sep 26 the center of Helene was located near 25.5, -85.5 with movement NNE at 14 mph. The minimum central pressure was 960 mb with maximum sustained winds of about 105 mph.

Issued at 1000 AM CDT Thu Sep 26 2024 000 WTNT34 KNHC 261454 TCPAT4 BULLETIN Hurricane Helene Advisory Number 13 NWS National Hurricane Center Miami FL AL092024 1000 AM CDT Thu Sep 26 2024 ...HELENE STRENGTHENING AND EXPECTED TO MAKE LANDFALL IN THE FLORIDA BIG BEND THIS EVENING AS A MAJOR HURRICANE... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...25.5N 85.5W ABOUT 255 MI...405 KM SW OF TAMPA FLORIDA ABOUT 290 MI...470 KM S OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H PRESENT MOVEMENT...NNE OR 25 DEGREES AT 14 MPH...22 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 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 1000 AM CDT (1500 UTC), the center of Hurricane Helene was located near latitude 25.5 North, longitude 85.5 West. Helene is moving toward the north-northeast near 14 mph (22 km/h). A significant increase in forward speed is expected during the next 24 hours. On the forecast track, Helene will make landfall in the Florida Big Bend region this evening. 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 105 mph (165 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. Helene is a very large hurricane. 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 minimum central pressure based on data from the Air Force Hurricane Hunters 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 The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. 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. 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 tropical storm warning areas in the southeastern U.S. through early Friday. Strong, damaging winds, especially in gusts, will likely penetrate as far inland as the higher terrain of the southern Appalachians. Tropical storm conditions are expected over portions of the warning area in western Cuba during the next couple of hours. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba. 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 20 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Numerous significant 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. For a list of rainfall observations (and wind reports) associated this storm, see the companion storm summary at WBCSCCNS4 with the WMO header ACUS44 KWBC or at the following link: www.wpc.ncep.noaa.gov/discussions/nfdscc4.html. 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 intermediate advisory at 100 PM CDT. Next complete advisory at 400 PM CDT. $$ Forecaster Cangialosi

Issued at 1500 UTC THU SEP 26 2024 000 FONT14 KNHC 261454 PWSAT4 HURRICANE HELENE WIND SPEED PROBABILITIES NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 1500 UTC THU SEP 26 2024 AT 1500Z THE CENTER OF HURRICANE HELENE WAS LOCATED NEAR LATITUDE 25.5 NORTH...LONGITUDE 85.5 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 90 KTS...105 MPH...165 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 12Z 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 12Z THU 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON PERIODS TO TO TO TO TO TO TO 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON 12Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CHARLOTTE NC 34 X 6( 6) 1( 7) X( 7) X( 7) X( 7) X( 7) FLORENCE SC 34 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) COLUMBIA SC 34 X 12(12) X(12) X(12) X(12) X(12) X(12) LITTLE RIVER 34 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) MYRTLE BEACH 34 X 9( 9) X( 9) X( 9) X( 9) X( 9) X( 9) GEORGETOWN SC 34 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) CHARLESTON SC 34 1 27(28) X(28) X(28) X(28) X(28) X(28) BEAUFORT MCAS 34 7 39(46) X(46) X(46) X(46) X(46) X(46) ATLANTA GA 34 1 82(83) 2(85) X(85) X(85) X(85) X(85) AUGUSTA GA 34 2 48(50) X(50) X(50) X(50) X(50) X(50) SAVANNAH GA 34 7 38(45) X(45) X(45) X(45) X(45) X(45) KINGS BAY GA 34 59 20(79) X(79) X(79) X(79) X(79) X(79) KINGS BAY GA 50 1 4( 5) X( 5) X( 5) X( 5) X( 5) X( 5) WAYCROSS GA 34 56 41(97) X(97) X(97) X(97) X(97) X(97) WAYCROSS GA 50 1 4( 5) X( 5) X( 5) X( 5) X( 5) X( 5) MAYPORT NS FL 34 64 15(79) X(79) X(79) X(79) X(79) X(79) MAYPORT NS FL 50 1 3( 4) X( 4) X( 4) X( 4) X( 4) X( 4) JACKSONVILLE 34 73 16(89) X(89) X(89) X(89) X(89) X(89) GAINESVILLE FL 34 99 1(99) X(99) X(99) X(99) X(99) X(99) GAINESVILLE FL 50 5 3( 8) X( 8) X( 8) X( 8) X( 8) X( 8) GAINESVILLE FL 64 X 1( 1) X( 1) X( 1) X( 1) X( 1) X( 1) DAYTONA BEACH 34 79 2(81) X(81) X(81) X(81) X(81) X(81) THE VILLAGES 34 98 X(98) X(98) X(98) X(98) X(98) X(98) THE VILLAGES 50 4 1( 5) X( 5) X( 5) X( 5) X( 5) X( 5) ORLANDO FL 34 87 1(88) X(88) X(88) X(88) X(88) X(88) COCOA BEACH FL 34 59 3(62) X(62) X(62) X(62) X(62) X(62) PATRICK AFB 34 60 2(62) X(62) X(62) X(62) X(62) X(62) FT PIERCE FL 34 42 3(45) X(45) X(45) X(45) X(45) X(45) W PALM BEACH 34 26 1(27) X(27) X(27) X(27) X(27) X(27) FT LAUDERDALE 34 21 X(21) X(21) X(21) X(21) X(21) X(21) MIAMI FL 34 9 1(10) X(10) X(10) X(10) X(10) X(10) HOMESTEAD ARB 34 8 X( 8) X( 8) X( 8) X( 8) X( 8) X( 8) MARATHON FL 34 30 X(30) X(30) X(30) X(30) X(30) X(30) KEY WEST FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) NAPLES FL 34 82 X(82) X(82) X(82) X(82) X(82) X(82) FT MYERS FL 34 95 X(95) X(95) X(95) X(95) X(95) X(95) VENICE FL 34 94 X(94) X(94) X(94) X(94) X(94) X(94) VENICE FL 50 6 X( 6) X( 6) X( 6) X( 6) X( 6) X( 6) TAMPA FL 34 95 X(95) X(95) X(95) X(95) X(95) X(95) TAMPA FL 50 16 X(16) X(16) X(16) X(16) X(16) X(16) TAMPA FL 64 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) CEDAR KEY FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) CEDAR KEY FL 50 64 5(69) X(69) X(69) X(69) X(69) X(69) CEDAR KEY FL 64 16 3(19) X(19) X(19) X(19) X(19) X(19) TALLAHASSEE FL 34 92 8(99) X(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 50 7 88(95) X(95) X(95) X(95) X(95) X(95) TALLAHASSEE FL 64 2 66(68) X(68) X(68) X(68) X(68) X(68) ST MARKS FL 34 98 2(99) X(99) X(99) X(99) X(99) X(99) ST MARKS FL 50 20 77(97) X(97) X(97) X(97) X(97) X(97) ST MARKS FL 64 6 73(79) X(79) X(79) X(79) X(79) X(79) APALACHICOLA 34 92 4(96) X(96) X(96) X(96) X(96) X(96) APALACHICOLA 50 48 34(82) X(82) X(82) X(82) X(82) X(82) APALACHICOLA 64 16 30(46) X(46) X(46) X(46) X(46) X(46) GFMX 290N 850W 34 98 X(98) X(98) X(98) X(98) X(98) X(98) GFMX 290N 850W 50 84 2(86) X(86) X(86) X(86) X(86) X(86) GFMX 290N 850W 64 55 4(59) X(59) X(59) X(59) X(59) X(59) PANAMA CITY FL 34 70 12(82) X(82) X(82) X(82) X(82) X(82) PANAMA CITY FL 50 8 23(31) X(31) X(31) X(31) X(31) X(31) PANAMA CITY FL 64 2 4( 6) X( 6) X( 6) X( 6) X( 6) X( 6) DESTIN EXEC AP 34 10 16(26) X(26) X(26) X(26) X(26) X(26) ALBANY GA 34 34 66(99) X(99) X(99) X(99) X(99) X(99) ALBANY GA 50 1 77(78) X(78) X(78) X(78) X(78) X(78) ALBANY GA 64 X 16(16) X(16) X(16) X(16) X(16) X(16) COLUMBUS GA 34 4 83(87) X(87) X(87) X(87) X(87) X(87) COLUMBUS GA 50 X 10(10) X(10) X(10) X(10) X(10) X(10) MACON GA 34 4 94(98) X(98) X(98) X(98) X(98) X(98) MACON GA 50 X 23(23) X(23) X(23) X(23) X(23) X(23) DOTHAN AL 34 22 63(85) X(85) X(85) X(85) X(85) X(85) DOTHAN AL 50 1 21(22) X(22) X(22) X(22) X(22) X(22) DOTHAN AL 64 X 3( 3) X( 3) X( 3) X( 3) X( 3) X( 3) BIRMINGHAM AL 34 1 5( 6) X( 6) X( 6) X( 6) X( 6) X( 6) MONTGOMERY AL 34 3 11(14) X(14) X(14) X(14) X(14) X(14) WHITING FLD FL 34 4 4( 8) X( 8) X( 8) X( 8) X( 8) X( 8) PENSACOLA FL 34 4 3( 7) X( 7) X( 7) X( 7) X( 7) X( 7) GFMX 290N 870W 34 23 3(26) X(26) X(26) X(26) X(26) X(26) GFMX 290N 870W 50 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) MOBILE AL 34 3 2( 5) X( 5) X( 5) X( 5) X( 5) X( 5) GULFPORT MS 34 3 1( 4) X( 4) X( 4) X( 4) X( 4) X( 4) BURAS LA 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) GFMX 280N 890W 34 4 1( 5) X( 5) X( 5) X( 5) X( 5) X( 5) 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 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) $$ FORECASTER CANGIALOSI

Issued at 1500 UTC THU SEP 26 2024 000 WTNT24 KNHC 261453 TCMAT4 HURRICANE HELENE FORECAST/ADVISORY NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 1500 UTC THU SEP 26 2024 HURRICANE CENTER LOCATED NEAR 25.5N 85.5W AT 26/1500Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 25 DEGREES AT 12 KT ESTIMATED MINIMUM CENTRAL PRESSURE 960 MB MAX SUSTAINED WINDS 90 KT WITH GUSTS TO 110 KT. 64 KT....... 50NE 50SE 0SW 40NW. 50 KT....... 80NE 80SE 50SW 50NW. 34 KT.......250NE 300SE 100SW 120NW. 12 FT SEAS..210NE 210SE 240SW 210NW. 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 25.5N 85.5W AT 26/1500Z AT 26/1200Z CENTER WAS LOCATED NEAR 24.7N 85.9W FORECAST VALID 27/0000Z 28.8N 84.3W MAX WIND 105 KT...GUSTS 130 KT. 64 KT... 45NE 50SE 30SW 20NW. 50 KT... 80NE 90SE 50SW 40NW. 34 KT...270NE 270SE 120SW 120NW. FORECAST VALID 27/1200Z 33.9N 84.5W...INLAND MAX WIND 55 KT...GUSTS 75 KT. 50 KT... 0NE 70SE 0SW 0NW. 34 KT...120NE 330SE 60SW 60NW. FORECAST VALID 28/0000Z 36.4N 86.6W...POST-TROP/EXTRATROP MAX WIND 30 KT...GUSTS 50 KT. FORECAST VALID 28/1200Z 36.5N 87.5W...POST-TROP/EXTRATROP MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 29/0000Z 36.3N 87.6W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 29/1200Z 36.2N 87.2W...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 30/1200Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.5N 85.5W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 26/1800Z NEXT ADVISORY AT 26/2100Z $$ FORECASTER CANGIALOSI

Storm Surge Watch/Warning Map last updated Thu, 26 Sep 2024 14:53:58 GMT

5-Day Uncertainty Track last updated Thu, 26 Sep 2024 14:42:48 GMT


Wind Speed Probabilities last updated Thu, 26 Sep 2024 15:29:22 GMT

Issued at 1100 AM AST Thu Sep 26 2024 000 WTNT45 KNHC 261437 TCDAT5 Tropical Storm Isaac Discussion Number 3 NWS National Hurricane Center Miami FL AL102024 1100 AM AST Thu Sep 26 2024 Isaac's structure has remained mostly steady state during the past 6 hours. Cloud tops associated with the tropical storm are still not particularly cold, but as noted in previous discussions, this is not unexpected for its synoptic environment. A blend of subjective Dvorak estimates from TAFB and SAB plus objective estimates from UW-CIMSS still supports an intensity of 45 kt for this advisory. For the next 48-60 h, the track forecast appears to be mostly straightforward. All reliable guidance indicates that Isaac will continue moving eastward to east-northeastward with a mid-latitude trough during that period. However, there is a significant bifurcation in the dynamical models after that. A majority of the guidance, including most of the ECMWF ensemble, indicate that Isaac will turn back eastward, continuing with the mid-latitude flow associated with another deep-layer trough. However, a few members of the global ensembles, plus the deterministic GFS, indicate Isaac could move slightly slower, which could cause the tropical storm to interact with a different trough, currently located over eastern Canada. This may cause the tropical cyclone to move northward after 60 h, on a very different track. The NHC forecast treats the GFS as an outlier, and is instead near the consensus of the remaining guidance. It is therefore very similar to the previous forecast. However, confidence in this forecast is particularly low, and we can't rule out needing to make an unusually large change to later forecasts. Isaac appears to be in an environment that should be generally conducive for some strengthening, especially during the next day or two. After that, unusually cold upper-tropospheric temperatures could help sustain the tropical cyclone for a while, even as it moves over colder SSTs in the 24-25 deg C. By the end of the forecast period, much colder SSTs and a dramatic increase in shear should cause Isaac to become post-tropical. No changes of note were made to the NHC forecast, which still shows Isaac reaching hurricane strength during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 37.3N 51.7W 45 KT 50 MPH 12H 27/0000Z 37.4N 49.8W 50 KT 60 MPH 24H 27/1200Z 37.9N 46.9W 55 KT 65 MPH 36H 28/0000Z 38.7N 43.5W 60 KT 70 MPH 48H 28/1200Z 39.9N 39.9W 65 KT 75 MPH 60H 29/0000Z 41.2N 36.7W 65 KT 75 MPH 72H 29/1200Z 42.3N 33.3W 60 KT 70 MPH 96H 30/1200Z 43.5N 25.5W 55 KT 65 MPH 120H 01/1200Z 43.5N 18.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster D. Zelinsky

Issued at 1500 UTC THU SEP 26 2024 000 FONT15 KNHC 261437 PWSAT5 TROPICAL STORM ISAAC WIND SPEED PROBABILITIES NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 1500 UTC THU SEP 26 2024 AT 1500Z THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 37.3 NORTH...LONGITUDE 51.7 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 12Z 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 12Z THU 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON PERIODS TO TO TO TO TO TO TO 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON 12Z 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) 5(22) X(22) PONTA DELGADA 34 X X( X) X( X) X( X) X( X) 2( 2) 1( 3) $$ FORECASTER D. ZELINSKY

...ISAAC FORECAST TO STRENGTHEN OVER THE NORTH ATLANTIC DURING THE NEXT COUPLE OF DAYS... As of 11:00 AM AST Thu Sep 26 the center of Isaac was located near 37.3, -51.7 with movement E at 12 mph. The minimum central pressure was 997 mb with maximum sustained winds of about 50 mph.