Issued at 1200 AM EDT Fri Sep 27 2024 000 WTNT64 KNHC 270401 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 1200 AM EDT Fri Sep 27 2024 ...EYEWALL OF EXTREMELY DANGEROUS CATEGORY 4 HELENE MOVING QUICKLY INLAND OVER THE FLORIDA PANHANDLE... ...1200 AM EDT POSITION UPDATE... Helene continues to produce catastrophic winds that are pushing further inland over the Florida Big Bend and Florida Panhandle and will soon be entering southeastern Georgia. This is an extremely dangerous and life-threatening situation. Persons should not leave their shelters and remain in place through the passage of these life-threatening conditions. When in the eye, people are reminded to not venture out in the relative calm, as hazardous winds will increase very quickly when the eye passes. An ASOS station at the Perry-Foley Airport recently reported a sustained wind of 55 mph (88 km/h) and a wind gust of 99 mph (159 km/h) while also reporting a minimum pressure of 948 mb (27.97 inches). A National Ocean Service tide gauge at Cedar Key is reporting a water level 8.68 feet above mean higher high water, which is an approximation of inundation in that area. SUMMARY OF 1200 AM EDT...0400 UTC...INFORMATION ---------------------------------------------- LOCATION...30.3N 83.6W ABOUT 80 MI...130 KM NNW OF CEDAR KEY FLORIDA ABOUT 45 MI...70 KM ESE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES $$ Forecaster Papin/Beven

Probabilistic Storm Surge Graphics last updated Fri, 27 Sep 2024 04:01:44 GMT

...HELENE MAKES LANDFALL IN THE FLORIDA BIG BEND... As of 11:20 PM EDT Thu Sep 26 the center of Helene was located near 30.0, -83.7 with movement NNE at 24 mph. The minimum central pressure was 938 mb with maximum sustained winds of about 140 mph.

Issued at 1120 PM EDT Thu Sep 26 2024 000 WTNT64 KNHC 270319 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 1120 PM EDT Thu Sep 26 2024 ...HELENE MAKES LANDFALL IN THE FLORIDA BIG BEND... Based on NWS Doppler radar data, the eye of Helene has made landfall as a Category 4 hurricane in the Florida Big Bend region at about 11:10 PM EDT (0310 UTC) just east of the mouth of the Aucilla River. This is about 10 miles (15 km) west-southwest of Perry, Florida. Based on data from Air Force reconnaissance aircraft, the maximum sustained winds are estimated to be 140 mph (225 km/h) and the minimum central pressure is 938 mb (27.70 inches). SUMMARY OF 1110 PM EDT...0310 UTC...INFORMATION ---------------------------------------------- LOCATION...30.0N 83.7W ABOUT 70 MI...115 KM NNW OF CEDAR KEY FLORIDA ABOUT 45 MI...70 KM ESE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...938 MB...27.70 INCHES $$ Forecaster Bucci/Sardi/Brown/Pasch/Hagen

5-Day Uncertainty Track last updated Fri, 27 Sep 2024 03:05:14 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2024 03:23:45 GMT

Storm Surge Watch/Warning Map last updated Fri, 27 Sep 2024 02:59:51 GMT

Issued at 1100 PM EDT Thu Sep 26 2024 000 WTNT44 KNHC 270258 TCDAT4 Hurricane Helene Discussion Number 15 NWS National Hurricane Center Miami FL AL092024 1100 PM EDT Thu Sep 26 2024 The hurricane is about to make landfall in the Florida Big Bend region. Timely observations from Air Force and NOAA Hurricane Hunter aircraft showed that Helene continued to strengthen rapidly to Category 4 status before it approached the coast, with the central pressure falling at about 3 mb per hour since this afternoon. Peak 700 mb flight-level winds from the aircraft were 136 kt, corresponding to an intensity of about 120 kt, which might be a bit conservative. Radar and satellite images show numerous mesocyclones rotating around the eyewall. The large hurricane continues moving rapidly north-northeastward with the latest initial motion estimated to be 015/21 kt. A generally northward track is expected overnight, taking the center from southern to northern Georgia through early Friday morning. Later on Friday and Saturday, Helene should slow down considerably while it interacts with a mid-level low to its northwest and west. The weakening system is likely to become nearly stationary in 48-60 hours. The official track forecast follows the dynamical model consensus. Although the system will weaken as it moves over land, the fast forward speed of Helene during the next 12 hours or so will result in a far inland penetration of strong winds over parts of the southeastern United States, particularly over Georgia, including strong gusts over the 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 occurring 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. 2. Catastrophic hurricane-force winds are occurring near the coast within the eyewall of Helene and will spread inland over portions of northern Florida and southern Georgia. 3. Damaging wind gusts will penetrate well inland over portions of Georgia and the Carolinas tonight, particularly over the higher terrain of the southern Appalachians. Residents in these areas should be prepared for the possibility of long-duration power outages. If you use a generator after the storm, be sure it is placed outside at least 20 feet away from doors, windows, and garages to avoid deadly carbon monoxide poisoning. 4. 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 27/0300Z 29.9N 83.9W 120 KT 140 MPH 12H 27/1200Z 33.9N 84.0W 55 KT 65 MPH...INLAND 24H 28/0000Z 36.9N 86.2W 30 KT 35 MPH...POST-TROP/EXTRATROP 36H 28/1200Z 36.8N 87.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 48H 29/0000Z 36.9N 86.9W 20 KT 25 MPH...POST-TROP/EXTRATROP 60H 29/1200Z 37.1N 86.4W 20 KT 25 MPH...POST-TROP/EXTRATROP 72H 30/0000Z...DISSIPATED $$ Forecaster Pasch

Issued at 1100 PM EDT Thu Sep 26 2024 000 WTNT34 KNHC 270258 TCPAT4 BULLETIN Hurricane Helene Advisory Number 15 NWS National Hurricane Center Miami FL AL092024 1100 PM EDT Thu Sep 26 2024 ...HURRICANE HELENE VERY CLOSE TO MAKING LANDFALL IN THE FLORIDA BIG BEND... ...ACCOMPANIED BY A CATASTROPHIC STORM SURGE AND LIFE-THREATENING WINDS... SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...29.9N 83.9W ABOUT 75 MI...120 KM NW OF CEDAR KEY FLORIDA ABOUT 40 MI...70 KM SE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...140 MPH...220 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...938 MB...27.70 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 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. 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 1100 PM EDT (0300 UTC), the center of Hurricane Helene was located near latitude 29.9 North, longitude 83.9 West. Helene is moving toward the north-northeast near 24 mph (39 km/h). A turn toward the north is expected overnight, taking the center over Georgia. The center of the hurricane should make landfall very soon in the Big Bend region of Florida. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday. Maximum sustained winds are near 140 mph (220 km/h) with higher gusts. Helene is an extremely dangerous category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Weakening is expected after Helene moves inland, but the 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 310 miles (500 km). A sustained wind of 64 mph (103 km/h) with a gust to 84 mph (135 km/h) was recently reported at Cedar Key, Florida. A gust of 83 mph (134 km/h) was recently reported at Steinhatchee, Florida. The estimated minimum central pressure based on Hurricane Hunter aircraft observations is 938 mb (27.70 inches). A NOAA National Ocean Service tide gauge located on Cedar Key recently reported a water level of 7.33 feet above mean higher high water. 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 occurring within the hurricane warning area. When the eye passes over, people are reminded to not venture out into the relative calm, as hazardous winds will increase very quickly when the eye passes. Tropical storm conditions are occurring in southern and central Florida, and these conditions will continue spreading 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: 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 continues tonight through early Friday morning over parts of north/central Florida, Georgia, South Carolina, and southern North Carolina. The tornado risk will persist Friday across the Carolinas and southern Virginia. SURF: Swells generated by Helene will affect much of Florida and the coasts of Georgia and the Carolinas during the next couple of days. 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 200 AM EDT. Next complete advisory at 500 AM EDT. $$ Forecaster Pasch

Issued at 0300 UTC FRI SEP 27 2024 000 FONT14 KNHC 270258 PWSAT4 HURRICANE HELENE WIND SPEED PROBABILITIES NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0300 UTC FRI SEP 27 2024 AT 0300Z THE CENTER OF HURRICANE HELENE WAS LOCATED NEAR LATITUDE 29.9 NORTH...LONGITUDE 83.9 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 120 KTS...140 MPH...220 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 00Z FRI 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 00Z FRI 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE PERIODS TO TO TO TO TO TO TO 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE 00Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CHARLOTTE NC 34 6 X( 6) X( 6) X( 6) X( 6) X( 6) X( 6) FLORENCE SC 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) COLUMBIA SC 34 23 X(23) X(23) X(23) X(23) X(23) X(23) LITTLE RIVER 34 4 X( 4) X( 4) X( 4) X( 4) X( 4) X( 4) MYRTLE BEACH 34 5 X( 5) X( 5) X( 5) X( 5) X( 5) X( 5) GEORGETOWN SC 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) CHARLESTON SC 34 26 X(26) X(26) X(26) X(26) X(26) X(26) BEAUFORT MCAS 34 74 X(74) X(74) X(74) X(74) X(74) X(74) ATLANTA GA 34 92 1(93) X(93) X(93) X(93) X(93) X(93) AUGUSTA GA 34 97 X(97) X(97) X(97) X(97) X(97) X(97) SAVANNAH GA 34 92 X(92) X(92) X(92) X(92) X(92) X(92) KINGS BAY GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) WAYCROSS GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) WAYCROSS GA 50 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) MAYPORT NS FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) JACKSONVILLE 34 99 X(99) X(99) X(99) X(99) X(99) X(99) GAINESVILLE FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) DAYTONA BEACH 34 99 X(99) X(99) X(99) X(99) X(99) X(99) THE VILLAGES 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ORLANDO FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) COCOA BEACH FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) PATRICK AFB 34 99 X(99) X(99) X(99) X(99) X(99) X(99) FT PIERCE FL 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) NAPLES FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) FT MYERS FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) VENICE FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) TAMPA FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) CEDAR KEY FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) CEDAR KEY FL 50 99 X(99) X(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 50 99 X(99) X(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 64 98 X(98) X(98) X(98) X(98) X(98) X(98) ST MARKS FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ST MARKS FL 50 99 X(99) X(99) X(99) X(99) X(99) X(99) ST MARKS FL 64 99 X(99) X(99) X(99) X(99) X(99) X(99) APALACHICOLA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) APALACHICOLA 50 75 X(75) X(75) X(75) X(75) X(75) X(75) GFMX 290N 850W 34 99 X(99) X(99) X(99) X(99) X(99) X(99) GFMX 290N 850W 50 99 X(99) X(99) X(99) X(99) X(99) X(99) PANAMA CITY FL 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ALBANY GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ALBANY GA 50 99 X(99) X(99) X(99) X(99) X(99) X(99) ALBANY GA 64 30 X(30) X(30) X(30) X(30) X(30) X(30) COLUMBUS GA 34 92 X(92) X(92) X(92) X(92) X(92) X(92) MACON GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) MACON GA 50 83 X(83) X(83) X(83) X(83) X(83) X(83) DOTHAN AL 34 95 X(95) X(95) X(95) X(95) X(95) X(95) $$ FORECASTER PASCH

Issued at 0300 UTC FRI SEP 27 2024 000 WTNT24 KNHC 270257 TCMAT4 HURRICANE HELENE FORECAST/ADVISORY NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0300 UTC FRI SEP 27 2024 HURRICANE CENTER LOCATED NEAR 29.9N 83.9W AT 27/0300Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 15 DEGREES AT 21 KT ESTIMATED MINIMUM CENTRAL PRESSURE 938 MB MAX SUSTAINED WINDS 120 KT WITH GUSTS TO 140 KT. 64 KT....... 50NE 50SE 30SW 40NW. 50 KT.......100NE 100SE 50SW 50NW. 34 KT.......240NE 270SE 100SW 120NW. 12 FT SEAS..150NE 340SE 420SW 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 29.9N 83.9W AT 27/0300Z AT 27/0000Z CENTER WAS LOCATED NEAR 28.7N 84.3W FORECAST VALID 27/1200Z 33.9N 84.0W...INLAND MAX WIND 55 KT...GUSTS 75 KT. 50 KT...100NE 100SE 40SW 40NW. 34 KT...220NE 260SE 100SW 60NW. FORECAST VALID 28/0000Z 36.9N 86.2W...POST-TROP/EXTRATROP MAX WIND 30 KT...GUSTS 50 KT. FORECAST VALID 28/1200Z 36.8N 87.5W...POST-TROP/EXTRATROP MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 29/0000Z 36.9N 86.9W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 29/1200Z 37.1N 86.4W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 30/0000Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 29.9N 83.9W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 27/0600Z NEXT ADVISORY AT 27/0900Z $$ FORECASTER PASCH

5-Day Uncertainty Track last updated Fri, 27 Sep 2024 02:46:56 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2024 03:29:49 GMT

Issued at 1100 PM AST Thu Sep 26 2024 000 WTNT45 KNHC 270242 TCDAT5 Tropical Storm Isaac Discussion Number 5 NWS National Hurricane Center Miami FL AL102024 1100 PM AST Thu Sep 26 2024 Isaac's structure has quickly improved this evening on satellite imagery. Deeper cold convection down to -60 C has been fully wrapping around the center, and the last few frames show a warm spot, which could very well be a formative eye. While the subjective Dvorak classifications hasn't changed much this evening, the objective estimates, especially DPRINT and DMINT from UW-CIMSS have increased to 54 and 51 kt respectively. Similar to last night, a late arriving set of scatterometer passes showed a tight vortex with derived-winds up to 49 kt. Assuming some undersampling of the small circulation, the initial intensity is raised to 55 kt this advisory. Isaac appears to have made a wobble south of due east earlier this evening, but more recently has resumed an eastward motion at 90/10 kt. This motion with a gradual turn to the east-northeast should occur over the next couple of days. Afterwards, the forward motion of Isaac is likely to become very critical to its future track trajectory. The poleward shift in the guidance that started earlier today has continued, possibly due to the slower forecasted forward motion of the storm, making it more likely to be captured by an upstream mid-latitude trough digging in from the west. The latest NHC track forecast has continued the northward shift started on the prior cycle, but is still not as far north and east as the bulk of the guidance suite, and further adjustments in that direction may be needed in future forecasts. Given the improvement in Isaac's structure this evening, it's looking increasingly likely the storm will soon become a hurricane. Vertical wind shear remains under 20 kt while sea-surface temperatures (SSTs) between 26-27 C for the next 24 h should allow additional intensification. After that time, shear begins to increase more as SSTs also begin to cool. These factors are expected to result in a leveling off in intensity, though cold upper-level temperatures should maintain enough instability to keep moderate to deep convection near the system. By 72 h, weakening should begin, with extratropical transition likely to be underway, finishing sometime early next week over the high-latitudes of the North Atlantic. The latest NHC intensity forecast is above much of the guidance in the short-term due to recent satellite trends, but falls back towards the reliable HCCA consensus aid after 24 hours. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 37.1N 49.8W 55 KT 65 MPH 12H 27/1200Z 37.1N 47.6W 65 KT 75 MPH 24H 28/0000Z 38.1N 44.1W 70 KT 80 MPH 36H 28/1200Z 39.5N 40.5W 70 KT 80 MPH 48H 29/0000Z 41.1N 37.9W 65 KT 75 MPH 60H 29/1200Z 42.6N 36.4W 65 KT 75 MPH 72H 30/0000Z 43.7N 35.1W 60 KT 70 MPH 96H 01/0000Z 46.0N 30.4W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 02/0000Z 50.0N 26.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin

Issued at 0300 UTC FRI SEP 27 2024 000 FONT15 KNHC 270239 PWSAT5 TROPICAL STORM ISAAC WIND SPEED PROBABILITIES NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0300 UTC FRI SEP 27 2024 AT 0300Z THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 37.1 NORTH...LONGITUDE 49.8 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 55 KTS...65 MPH...100 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 00Z FRI 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 00Z FRI 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE PERIODS TO TO TO TO TO TO TO 12Z FRI 00Z SAT 12Z SAT 00Z SUN 00Z MON 00Z TUE 00Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X X( X) X( X) 1( 1) 6( 7) 1( 8) X( 8) $$ FORECASTER PAPIN

...ISAAC STRENGTHENING AND LIKELY TO BECOME A HURRICANE SOON... As of 11:00 PM AST Thu Sep 26 the center of Isaac was located near 37.1, -49.8 with movement E at 12 mph. The minimum central pressure was 992 mb with maximum sustained winds of about 65 mph.

Issued at 1100 PM AST Thu Sep 26 2024 000 WTNT35 KNHC 270239 TCPAT5 BULLETIN Tropical Storm Isaac Advisory Number 5 NWS National Hurricane Center Miami FL AL102024 1100 PM AST Thu Sep 26 2024 ...ISAAC STRENGTHENING AND LIKELY TO BECOME A HURRICANE SOON... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...37.1N 49.8W ABOUT 1245 MI...2005 KM W OF THE AZORES ABOUT 910 MI...1470 KM ENE OF BERMUDA MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...E OR 90 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 1100 PM AST (0300 UTC), the center of Tropical Storm Isaac was located near latitude 37.1 North, longitude 49.8 West. Isaac is moving toward the east near 12 mph (19 km/h) and this motion with a turn more east-northeastward is expected over the next several days. Satellite wind data suggests that maximum sustained winds have increased to near 65 mph (100 km/h) with higher gusts. Additional strengthening is expected during the next day or so and Isaac is forecast to become a hurricane tomorrow. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 992 mb (29.30 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 500 AM AST. $$ Forecaster Papin

Issued at 0300 UTC FRI SEP 27 2024 000 WTNT25 KNHC 270237 TCMAT5 TROPICAL STORM ISAAC FORECAST/ADVISORY NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0300 UTC FRI SEP 27 2024 TROPICAL STORM CENTER LOCATED NEAR 37.1N 49.8W AT 27/0300Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE EAST OR 90 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 992 MB MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. 50 KT....... 0NE 30SE 30SW 0NW. 34 KT....... 30NE 40SE 50SW 40NW. 12 FT SEAS.. 60NE 120SE 150SW 240NW. 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 49.8W AT 27/0300Z AT 27/0000Z CENTER WAS LOCATED NEAR 37.1N 50.3W FORECAST VALID 27/1200Z 37.1N 47.6W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 0NE 20SE 0SW 0NW. 50 KT... 25NE 50SE 40SW 20NW. 34 KT... 50NE 80SE 60SW 40NW. FORECAST VALID 28/0000Z 38.1N 44.1W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 0NE 20SE 15SW 0NW. 50 KT... 25NE 50SE 35SW 25NW. 34 KT... 70NE 100SE 80SW 60NW. FORECAST VALID 28/1200Z 39.5N 40.5W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 0NE 20SE 15SW 10NW. 50 KT... 35NE 50SE 50SW 35NW. 34 KT...100NE 120SE 100SW 90NW. FORECAST VALID 29/0000Z 41.1N 37.9W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 0NE 20SE 15SW 0NW. 50 KT... 60NE 60SE 50SW 50NW. 34 KT...165NE 130SE 100SW 130NW. FORECAST VALID 29/1200Z 42.6N 36.4W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 50NE 50SE 40SW 50NW. 34 KT...150NE 130SE 110SW 130NW. FORECAST VALID 30/0000Z 43.7N 35.1W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 50NE 60SE 60SW 50NW. 34 KT...180NE 130SE 110SW 160NW. 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 01/0000Z 46.0N 30.4W...POST-TROP/EXTRATROP MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 50NE 60SE 50SW 40NW. 34 KT...170NE 120SE 90SW 120NW. OUTLOOK VALID 02/0000Z 50.0N 26.0W...POST-TROP/EXTRATROP MAX WIND 40 KT...GUSTS 50 KT. 34 KT...150NE 130SE 80SW 120NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.1N 49.8W NEXT ADVISORY AT 27/0900Z $$ FORECASTER PAPIN

...EYEWALL OF EXTREMELY DANGEROUS CATEGORY 4 HELENE BEGINNING TO MOVE ASHORE ALONG THE FLORIDA COAST OF THE BIG BEND... ...1000 PM EDT POSITION UPDATE... As of 10:00 PM EDT Thu Sep 26 the center of Helene was located near 29.5, -84.1 with movement NNE at 24 mph. The minimum central pressure was 939 mb with maximum sustained winds of about 140 mph.

Issued at 1000 PM EDT Thu Sep 26 2024 000 WTNT64 KNHC 270159 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 1000 PM EDT Thu Sep 26 2024 ...EYEWALL OF EXTREMELY DANGEROUS CATEGORY 4 HELENE BEGINNING TO MOVE ASHORE ALONG THE FLORIDA COAST OF THE BIG BEND... ...1000 PM EDT POSITION UPDATE... Helene is producing catastrophic winds that will be spreading onshore in the Florida Big Bend region during the next few hours. This is an extremely dangerous and life-threatening situation. Persons should not leave their shelters and remain in place through the passage of these life-threatening conditions. When the eye comes ashore, people are reminded to not venture out in the relative calm, as hazardous winds will increase very quickly when the eye passes. A University of Florida Coastal Monitoring Program tower located on Cedar Key recently reported a sustained wind of 59 mph (95 km/h) and a wind gust of 78 mph (126 km/h). A NOAA National Ocean Service tide gauge located at Clearwater Beach recently reported a water level of 6.18 feet above mean higher high water, which is an approximation of inundation in that area. A National Ocean Service tide gauge at Cedar Key is reporting a water level 5.76 feet above mean higher high water. SUMMARY OF 1000 PM EDT...0200 UTC...INFORMATION ---------------------------------------------- LOCATION...29.5N 84.1W ABOUT 65 MI...105 KM WNW OF CEDAR KEY FLORIDA ABOUT 65 MI...105 KM S OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...939 MB...27.72 INCHES $$ Forecaster Bucci/Sardi/Brown

...HELENE SLIGHTLY STRONGER AS ITS EYE APPROACHES THE COAST OF THE FLORIDA BIG BEND... ...900 PM EDT POSITION UPDATE... As of 9:00 PM EDT Thu Sep 26 the center of Helene was located near 29.1, -84.2 with movement NNE at 24 mph. The minimum central pressure was 941 mb with maximum sustained winds of about 140 mph.

Issued at 900 PM EDT Thu Sep 26 2024 000 WTNT64 KNHC 270056 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 900 PM EDT Thu Sep 26 2024 ...HELENE SLIGHTLY STRONGER AS ITS EYE APPROACHES THE COAST OF THE FLORIDA BIG BEND... ...900 PM EDT POSITION UPDATE... A University of Florida Coastal Monitoring Program tower located on Cedar Key recently reported a sustained wind of 55 mph (89 km/h) and a wind gust of 73 mph (117 km/h). A NOAA National Ocean Service tide gauge located at Clearwater Beach recently reported a water level of 5.07 feet above mean higher high water, which is an approximation of inundation in that area. SUMMARY OF 900 PM EDT...0100 UTC...INFORMATION ---------------------------------------------- LOCATION...29.1N 84.2W ABOUT 65 MI...105 KM W OF CEDAR KEY FLORIDA ABOUT 90 MI...145 KM S OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...140 MPH...225 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES $$ Forecaster Bucci/Sardi