5-Day Uncertainty Track last updated Fri, 27 Sep 2024 09:00:12 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2024 09:00:12 GMT

Storm Surge Watch/Warning Map last updated Fri, 27 Sep 2024 08:59:00 GMT

Issued at 500 AM EDT Fri Sep 27 2024 000 WTNT44 KNHC 270854 TCDAT4 Tropical Storm Helene Discussion Number 16 NWS National Hurricane Center Miami FL AL092024 500 AM EDT Fri Sep 27 2024 The eye of Helene made landfall near Perry, Florida, just after the last advisory was issued. Since then, the center has crossed the Florida Big Bend region and is currently located over east central Georgia. Surface observations have shown steady weakening since landfall, and the maximum winds have decreased to a possibly generous 60 kt. During the last couple of hours, the radar signature of the cyclone has degraded, and based on this the hourly Tropical Cyclone Updates will be discontinued. The initial motion is now northward or 360/26. Helen should turn northwestward later today as it starts to interact with a mid- to upper-level baroclinic low to its northwest. After that, the cyclone should considerably slow its forward motion and make a cyclonic loop as it gets absorbed into the low. The new forecast track follows the general trend of the large-scale dynamical models. Helene should continue to weaken, and simulated satellite imagery suggests it should lose its convection later today, the new intensity forecast calls for the cyclone to weaken and become post-tropical in about 12 h, followed by transition to an extratropical cyclone as it merges with the baroclinic low. The remnant extratropical low is expected to dissipate by 72 h. 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 northern 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. The storm surge along portions of the Florida Big Bend coast and other portions of the west coast of Florida should subside today. 2. Damaging wind gusts will continue to penetrate well inland over portions of Georgia and the Carolinas today, 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. 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 is likely, some of which will be major to record breaking. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 32.8N 83.0W 60 KT 70 MPH...INLAND 12H 27/1800Z 36.4N 84.5W 35 KT 40 MPH...POST-TROP/INLAND 24H 28/0600Z 36.9N 87.3W 30 KT 35 MPH...POST-TROP/EXTRATROP 36H 28/1800Z 36.7N 87.3W 25 KT 30 MPH...POST-TROP/EXTRATROP 48H 29/0600Z 36.7N 87.0W 20 KT 25 MPH...POST-TROP/EXTRATROP 60H 29/1800Z 36.9N 86.0W 20 KT 25 MPH...POST-TROP/EXTRATROP 72H 30/0600Z...DISSIPATED $$ Forecaster Beven

5-Day Uncertainty Track last updated Fri, 27 Sep 2024 08:54:27 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2024 09:29:10 GMT

Issued at 0900 UTC FRI SEP 27 2024 000 FONT14 KNHC 270854 PWSAT4 TROPICAL STORM HELENE WIND SPEED PROBABILITIES NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0900 UTC FRI SEP 27 2024 AT 0900Z THE CENTER OF TROPICAL STORM HELENE WAS LOCATED NEAR LATITUDE 32.8 NORTH...LONGITUDE 83.0 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 60 KTS...70 MPH...110 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 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 06Z FRI 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE PERIODS TO TO TO TO TO TO TO 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE 06Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CHARLOTTE NC 34 10 X(10) X(10) X(10) X(10) X(10) X(10) COLUMBIA SC 34 96 X(96) X(96) X(96) X(96) X(96) X(96) LITTLE RIVER 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) MYRTLE BEACH 34 4 X( 4) X( 4) X( 4) X( 4) X( 4) X( 4) CHARLESTON SC 34 99 X(99) X(99) X(99) X(99) X(99) X(99) BEAUFORT MCAS 34 99 X(99) X(99) X(99) X(99) X(99) X(99) ATLANTA GA 34 77 X(77) X(77) X(77) X(77) X(77) X(77) AUGUSTA GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) SAVANNAH GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) 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) 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) CEDAR KEY FL 34 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) ST MARKS 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) COLUMBUS GA 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) MACON GA 34 99 X(99) X(99) X(99) X(99) X(99) X(99) MACON GA 50 39 X(39) X(39) X(39) X(39) X(39) X(39) MACON GA 64 7 X( 7) X( 7) X( 7) X( 7) X( 7) X( 7) $$ FORECASTER BEVEN

Issued at 500 AM EDT Fri Sep 27 2024 467 WTNT34 KNHC 270853 TCPAT4 BULLETIN Tropical Storm Helene Advisory Number 16 NWS National Hurricane Center Miami FL AL092024 500 AM EDT Fri Sep 27 2024 ...HELENE WEAKENS TO A TROPICAL STORM AS IT MOVES FARTHER INLAND OVER GEORGIA... ...LIFE-THREATENING STORM SURGE, WINDS, AND HEAVY RAINS CONTINUE... SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...32.8N 83.0W ABOUT 40 MI...65 KM E OF MACON GEORGIA ABOUT 100 MI...165 KM SE OF ATLANTA GEORGIA MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...N OR 360 DEGREES AT 30 MPH...48 KM/H MINIMUM CENTRAL PRESSURE...968 MB...28.59 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: All Hurricane and Tropical Storm warnings have been discontinued along the Florida east coast south of the Flagler/Volusia county line, and along the Florida west coast south of the mouth of the Suwannee River. The Hurricane Warning for the Florida coast from the mouth of the Suwannee Rover to Mexico Beach has been changed to a Tropical Storm Warning. The Tropical Storm Warning has been discontinued for the Florida Gulf coast west of Indian Pass. The Storm Surge Warning for the Florida coast has been discontinued west of Indian Pass and south of Bonita Beach. The Hurricane Watch for the Florida West coast has been discontinued. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * Indian Pass to Bonita Beach * Tampa Bay A Tropical Storm Warning is in effect for... * The mouth of the Suwannee River to Indian Pass * The Flagler/Volusia county line northward to Little River Inlet 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 Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning 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. DISCUSSION AND OUTLOOK ---------------------- At 500 AM EDT (0900 UTC), the center of Tropical Storm Helene was located near latitude 32.8 North, longitude 83.0 West. Helene is moving toward the north near 30 mph (48 km/h). A turn toward the north is expected this morning, taking the center over central and northeastern Georgia. After that, Helene is expected to turn northwestward and slow down over the Tennessee Valley later today and Saturday. Maximum sustained winds have decreased to near 70 mph (110 km/h) with higher gusts. Continued weakening is expected, and Helene is expected to become a post-tropical low this afternoon or tonight. However, 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. Tropical-storm-force winds extend outward up to 275 miles (445 km) mainly to the east of the center. The Marine Corp Air Station at Beaufort, South Carolina, recently reported a wind gust of 75 mph (120 km/h). The minimum central pressure based on surface observations is 968 mb (28.59 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... Aucilla River, FL to Chassahowitzka, FL...5-10 ft Chassahowitzka, FL to Anclote River, FL...4-7 ft Indian Pass, FL to Aucilla River, FL...3-6 ft Anclote River, FL to Englewood, FL...3-5 ft Tampa Bay...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: Tropical storm conditions are occurring from northern Florida through eastern Georgia into southern South Carolina, and these conditions will continue spreading northward across the tropical storm warning areas in the Southeastern U.S. through today. 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 and record 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: Tornadoes are possible this morning over parts of eastern Georgia, and through this afternoon over 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 800 AM EDT. Next complete advisory at 1100 AM EDT. $$ Forecaster Beven

Issued at 0900 UTC FRI SEP 27 2024 000 WTNT24 KNHC 270853 TCMAT4 TROPICAL STORM HELENE FORECAST/ADVISORY NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0900 UTC FRI SEP 27 2024 TROPICAL STORM CENTER LOCATED NEAR 32.8N 83.0W AT 27/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTH OR 360 DEGREES AT 26 KT ESTIMATED MINIMUM CENTRAL PRESSURE 968 MB MAX SUSTAINED WINDS 60 KT WITH GUSTS TO 80 KT. 50 KT....... 30NE 50SE 30SW 0NW. 34 KT.......240NE 240SE 100SW 60NW. 12 FT SEAS..240NE 380SE 390SW 0NW. 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 32.8N 83.0W AT 27/0900Z...INLAND AT 27/0600Z CENTER WAS LOCATED NEAR 31.3N 83.3W...INLAND FORECAST VALID 27/1800Z 36.4N 84.5W...POST-TROP/INLAND MAX WIND 35 KT...GUSTS 50 KT. 34 KT...120NE 0SE 0SW 120NW. FORECAST VALID 28/0600Z 36.9N 87.3W...POST-TROP/EXTRATROP MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 28/1800Z 36.7N 87.3W...POST-TROP/EXTRATROP MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 29/0600Z 36.7N 87.0W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 29/1800Z 36.9N 86.0W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 30/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 32.8N 83.0W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 27/1200Z NEXT ADVISORY AT 27/1500Z $$ FORECASTER BEVEN

Issued at 500 AM AST Fri Sep 27 2024 256 WTNT45 KNHC 270852 TCDAT5 Hurricane Isaac Discussion Number 6 NWS National Hurricane Center Miami FL AL102024 500 AM AST Fri Sep 27 2024 Isaac has continued to become better organized since the prior advisory. The earlier warm spot noted on IR satellite imagery has persisted and warmed further, with sufficently cold -55 to -60 C convective cloud tops encircling the feature. A helpful AMSR2 pass that became available after the prior advisory also showed an eye feature on both the 89-GHz and 37-GHz channels, the latter showing a cyan ring. These features suggest that Isaac has become a hurricane, and the initial intensity has been raised to 65 kt for this advisory. Isaac still is moving generally eastward this morning, estimated at 090/10 kt. This motion with a gradual turn to the east-northeast should occur over the next couple of days as the hurricane remains steered mostly by deep-layer flow along the northern periphery of a mid-level ridge centered to the southeast of Isaac. Once again, how quick this forward motion ends up being will be critical for its ultimate track down the road, with a track bifurcation continuing between the GFS and ECMWF solutions occuring beyond 60 h as to how much the upstream trough located to its east is able to interact and pick up the cyclone. Despite the spread in the guidance, the consensus aids are not that much altered from the prior cycle, and the NHC track forecast is quite similar to the prior advisory. Additional intensification is expected while the vertical wind shear remains only low to moderate and Isaac continues to be over sufficently warm sea-surface temperatures (SSTs) with instability being aided by cold upper-level temperatures. After 36 h, SSTs drop to 24 C and lower as shear increases markedly, which should induce a gradual weakening trend. Both the GFS and ECMWF suggest the cyclone should lose its deep convection sometime in the 72-96 h period, marking its transition to post-tropical in that time frame. The NHC intensity forecast is on the high side of the guidance, but is generally in line with the latest GFS-based SHIPS and LGEM guidance. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 37.0N 48.5W 65 KT 75 MPH 12H 27/1800Z 37.5N 45.9W 70 KT 80 MPH 24H 28/0600Z 38.8N 42.4W 75 KT 85 MPH 36H 28/1800Z 40.4N 39.3W 75 KT 85 MPH 48H 29/0600Z 41.8N 37.3W 70 KT 80 MPH 60H 29/1800Z 43.1N 35.9W 60 KT 70 MPH 72H 30/0600Z 44.0N 34.3W 55 KT 65 MPH 96H 01/0600Z 46.9N 30.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 02/0600Z 50.4N 26.2W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin

...ISAAC BECOMES A HURRICANE... As of 5:00 AM AST Fri Sep 27 the center of Isaac was located near 37.0, -48.5 with movement E at 12 mph. The minimum central pressure was 981 mb with maximum sustained winds of about 75 mph.

Issued at 500 AM AST Fri Sep 27 2024 000 WTNT35 KNHC 270850 TCPAT5 BULLETIN Hurricane Isaac Advisory Number 6 NWS National Hurricane Center Miami FL AL102024 500 AM AST Fri Sep 27 2024 ...ISAAC BECOMES A HURRICANE... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...37.0N 48.5W ABOUT 1175 MI...1895 KM W OF THE AZORES ABOUT 980 MI...1575 KM ENE OF BERMUDA MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H PRESENT MOVEMENT...E OR 90 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...981 MB...28.97 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 Hurricane Isaac was located near latitude 37.0 North, longitude 48.5 West. Isaac is moving toward the east near 12 mph (19 km/h) and this motion with a gradual turn to the east-northeast is expected over the next several days. Maximum sustained winds are near 75 mph (120 km/h) with higher gusts. Additional strengthening is expected during the next day or so followed by gradual weakening by the end of this weekend. Hurricane-force winds extend outward up to 15 miles (30 km) from the center and tropical-storm-force winds extend outward up to 70 miles (110 km). The estimated minimum central pressure is 981 mb (28.97 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 FRI SEP 27 2024 000 FONT15 KNHC 270850 PWSAT5 HURRICANE ISAAC WIND SPEED PROBABILITIES NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC FRI SEP 27 2024 AT 0900Z THE CENTER OF HURRICANE ISAAC WAS LOCATED NEAR LATITUDE 37.0 NORTH...LONGITUDE 48.5 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 65 KTS...75 MPH...120 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 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 06Z FRI 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE PERIODS TO TO TO TO TO TO TO 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE 06Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X X( X) X( X) 2( 2) 4( 6) 1( 7) X( 7) $$ FORECASTER PAPIN

Issued at 0900 UTC FRI SEP 27 2024 000 WTNT25 KNHC 270850 TCMAT5 HURRICANE ISAAC FORECAST/ADVISORY NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC FRI SEP 27 2024 HURRICANE CENTER LOCATED NEAR 37.0N 48.5W AT 27/0900Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE EAST OR 90 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 981 MB MAX SUSTAINED WINDS 65 KT WITH GUSTS TO 75 KT. 64 KT....... 0NE 15SE 0SW 0NW. 50 KT....... 20NE 40SE 30SW 20NW. 34 KT....... 40NE 60SE 60SW 60NW. 12 FT SEAS.. 70NE 150SE 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 37.0N 48.5W AT 27/0900Z AT 27/0600Z CENTER WAS LOCATED NEAR 37.0N 49.2W FORECAST VALID 27/1800Z 37.5N 45.9W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 0NE 20SE 15SW 0NW. 50 KT... 30NE 50SE 40SW 30NW. 34 KT... 60NE 80SE 70SW 60NW. FORECAST VALID 28/0600Z 38.8N 42.4W MAX WIND 75 KT...GUSTS 90 KT. 64 KT... 15NE 20SE 15SW 10NW. 50 KT... 25NE 50SE 40SW 30NW. 34 KT...100NE 120SE 100SW 90NW. FORECAST VALID 28/1800Z 40.4N 39.3W MAX WIND 75 KT...GUSTS 90 KT. 64 KT... 15NE 20SE 15SW 10NW. 50 KT... 40NE 55SE 50SW 40NW. 34 KT...160NE 130SE 110SW 120NW. FORECAST VALID 29/0600Z 41.8N 37.3W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 0NE 20SE 15SW 10NW. 50 KT... 55NE 60SE 55SW 50NW. 34 KT...190NE 130SE 110SW 160NW. FORECAST VALID 29/1800Z 43.1N 35.9W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 40NE 55SE 45SW 45NW. 34 KT...190NE 130SE 110SW 180NW. FORECAST VALID 30/0600Z 44.0N 34.3W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 0NE 50SE 35SW 30NW. 34 KT...160NE 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 01/0600Z 46.9N 30.4W...POST-TROP/EXTRATROP MAX WIND 45 KT...GUSTS 55 KT. 34 KT...190NE 110SE 90SW 110NW. OUTLOOK VALID 02/0600Z 50.4N 26.2W...POST-TROP/EXTRATROP MAX WIND 35 KT...GUSTS 45 KT. 34 KT...190NE 180SE 80SW 0NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.0N 48.5W NEXT ADVISORY AT 27/1500Z $$ FORECASTER PAPIN

...HELENE PRODUCING HISTORIC AND CATASTROPHIC FLOODING OVER PORTIONS OF THE SOUTHEAST AND SOUTHERN APPALACHIANS... ...FLASH FLOOD EMERGENCIES IN EFFECT FOR METROPOLITAN ATLANTA, AND MUCH OF UPSTATE SOUTH CAROLINA AND WESTERN NORTH CAROLINA... As of 11:00 AM EDT Fri Sep 27 the center of Helene was located near 35.1, -83.8 with movement N at 32 mph. The minimum central pressure was 975 mb with maximum sustained winds of about 45 mph.

...HURRICANE HELENE ACCELERATING NORTH-NORTHEAST THROUGH GEORGIA... ...300 AM EDT POSITION UPDATE... As of 3:00 AM EDT Fri Sep 27 the center of Helene was located near 31.9, -83.1 with movement NNE at 30 mph. The minimum central pressure was 960 mb with maximum sustained winds of about 80 mph.

Issued at 300 AM EDT Fri Sep 27 2024 000 WTNT64 KNHC 270704 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 300 AM EDT Fri Sep 27 2024 ...HURRICANE HELENE ACCELERATING NORTH-NORTHEAST THROUGH GEORGIA... ...300 AM EDT POSITION UPDATE... Helene continues to produce hurricane force winds that are moving further into Georgia. This is an 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 center passes. An ASOS station at Alma Bacon County Airport in Georgia recently reported a wind gust of 91 mph (146 km/h). Another weather station in Douglas, Georgia recently reported a wind gust of 92 mph (148 km/h). SUMMARY OF 300 AM EDT...0700 UTC...INFORMATION ---------------------------------------------- LOCATION...31.9N 83.1W ABOUT 75 MI...120 KM N OF VALDOSTA GEORGIA ABOUT 55 MI...115 KM SSE OF MACON GEORGIA MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 30 MPH...48 KM/H MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES $$ Forecaster Papin/Beven

Issued at 200 AM EDT Fri Sep 27 2024 000 WTNT34 KNHC 270556 TCPAT4 BULLETIN Hurricane Helene Intermediate Advisory Number 15A NWS National Hurricane Center Miami FL AL092024 200 AM EDT Fri Sep 27 2024 ...HELENE WEAKENING AS IT MOVES QUICKLY NORTH-NORTHEASTWARD NEAR VALDOSTA GEORGIA... ...LIFE-THREATENING STORM SURGE, WINDS, AND HEAVY RAINS CONTINUE... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...31.2N 83.3W ABOUT 30 MI...50 KM N OF VALDOSTA GEORGIA ABOUT 85 MI...135 KM NE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...90 MPH...145 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 26 MPH...42 KM/H MINIMUM CENTRAL PRESSURE...955 MB...28.20 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Tropical Storm Warning has been discontinued for the Florida Keys, including the Dry Tortugas. 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... * 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. DISCUSSION AND OUTLOOK ---------------------- At 200 AM EDT (0600 UTC), the center of Hurricane Helene was located near latitude 31.2 North, longitude 83.3 West. Helene is moving toward the north-northeast near 26 mph (42 km/h). A turn toward the north is expected overnight, taking the center over central and northern Georgia this morning. After that, Helene is expected to turn northwestward and slow down over the Tennessee Valley later today and Saturday. Maximum sustained winds have decreased to near near 90 mph (145 km/h) with higher gusts. Continued weakening is expected, 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 30 miles (50 km) from the center and tropical-storm-force winds extend outward up to 310 miles (500 km), mainly to the east of the center. A automated station at Grassy Pond, Georgia, just south of Valdosta, recently reported a wind gust of 96 mph (154 km/h). On the Atlantic coast of Georgia, Savannah International Airport recently reported a wind gust of 75 mph (120 km/h.) The minimum central pressure based on surface observations in the Valdosta area is 955 mb (28.20 inches). A NOAA National Ocean Service tide gauge located on Cedar Key recently reported a water level of 9.30 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 from southern Florida to southeastern Georgia, and these conditions will continue spreading northward across the tropical storm warning areas in the Southeastern U.S. through today. 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 this morning over parts of north/central Florida, Georgia, South Carolina, and southern North Carolina. The tornado risk will persist today 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 complete advisory at 500 AM EDT. Next Tropical Cyclone Update at 300 and 400 AM EDT. $$ Forecaster Beven

000
ABNT20 KNHC 270542
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Fri Sep 27 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 inland over southern Georgia 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 midway in between the Cabo Verde Islands and the Lesser
Antilles continues to remain well organized. Environmental
conditions are currently conducive for further development and a
tropical depression or storm could form at any time today while the
system moves generally westward to west-northwestward at 10 to 15
mph. The system is then forecast to slow down and turn
north-northwestward by this weekend.
* 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 Sea by
the middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter, while the system moves
generally northwestward, potentially entering the Gulf of Mexico by
the end of next week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.

$$
Forecaster Papin

...HELENE WEAKENING AS IT MOVES QUICKLY NORTH-NORTHEASTWARD NEAR VALDOSTA GEORGIA... ...LIFE-THREATENING STORM SURGE, WINDS, AND HEAVY RAINS CONTINUE... As of 2:00 AM EDT Fri Sep 27 the center of Helene was located near 31.2, -83.3 with movement NNE at 26 mph. The minimum central pressure was 955 mb with maximum sustained winds of about 90 mph.

Issued at 100 AM EDT Fri Sep 27 2024 000 WTNT64 KNHC 270501 TCUAT4 Hurricane Helene Tropical Cyclone Update NWS National Hurricane Center Miami FL AL092024 100 AM EDT Fri Sep 27 2024 ...EYEWALL OF EXTREMELY DANGEROUS HURRICANE HELENE NOW MOVING INTO GEORGIA AND ACCELERATING NORTH-NORTHEAST... ...100 AM EDT POSITION UPDATE... Helene continues to produce catastrophic winds that are now pushing into southern 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. A WeatherSTEM site in southern Lowndes County in Georgia recently reported a wind gust to 88 mph (142 km/h). Another Weather Stem site in Kinderlou, Georgia recently reported a minimum pressure of 952.2 mb (28.11 inches) in the eye of Helene. A USGS tide gauge at Steinhatchee, Florida earlier reported a water level 9.6 feet above mean higher high water, which is an approximation of inundation in that area. SUMMARY OF 100 AM EDT...0500 UTC...INFORMATION ---------------------------------------------- LOCATION...30.8N 83.5W ABOUT 10 MI...20 KM WSW OF VALDOSTA GEORGIA ABOUT 55 MI...90 KM ENE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 26 MPH...42 KM/H MINIMUM CENTRAL PRESSURE...950 MB...28.05 INCHES $$ Forecaster Papin/Beven

Potential Storm Surge Flooding Map last updated Fri, 27 Sep 2024 04:35:14 GMT