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...JOHN EXPECTED TO BECOME A HURRICANE... ...HURRICANE WARNING ISSUED FOR SOUTHWESTERN MEXICO... As of 3:00 PM CST Wed Sep 25 the center of John was located near 16.8, -101.5 with movement N at 3 mph. The minimum central pressure was 996 mb with maximum sustained winds of about 50 mph.

Issued at 300 PM CST Wed Sep 25 2024 775 WTPZ35 KNHC 252051 TCPEP5 BULLETIN Tropical Storm John Advisory Number 12 NWS National Hurricane Center Miami FL EP102024 300 PM CST Wed Sep 25 2024 ...JOHN EXPECTED TO BECOME A HURRICANE... ...HURRICANE WARNING ISSUED FOR SOUTHWESTERN MEXICO... SUMMARY OF 300 PM CST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...16.8N 101.5W ABOUT 105 MI...170 KM W OF ACAPULCO MEXICO ABOUT 60 MI...100 KM S OF ZIHUATANEJO MEXICO MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...N OR 355 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of Mexico has issued a Hurricane Warning for the coast of Mexico from Tecpan de Galeana to Lazaro Cardenas. The government of Mexico has issued a Hurricane Watch for the coast of Mexico from west of Lazaro Cardenas to Punta San Telmo. The government of Mexico has issued a Tropical Storm Warning for the coast of Mexico from west of Lazaro Cardenas to Punta San Telmo. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Tecpan de Galeana to Lazaro Cardenas A Hurricane Watch is in effect for... * Acapulco to Tecpan de Galeana * Lazaro Cardenas to Punta San Telmo A Tropical Storm Warning is in effect for... * Punta Maldonado to Acapulco * Lazaro Cardenas to Punta San Telmo A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area, this is case within 12 to 24 hours. Preparations to protect life and property should be rushed to completion. A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within 12 hours. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12 hours. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 300 PM CST (2100 UTC), the center of Tropical Storm John was located near latitude 16.8 North, longitude 101.5 West. John is moving toward the north near 3 mph (6 km/h). This motion should continue for the next day or so, followed by a gradual turn to the west-northwest on Friday. On the forecast track, the center of John is forecast to approach the southwestern coast of Mexico on early Thursday and be inland on Friday. Maximum sustained winds have increased to near 50 mph (85 km/h) with higher gusts. John is forecast to strengthen as it approaches the coast of southern Mexico on Thursday. Tropical-storm-force winds extend outward up to 150 miles (240 km) from the center. The estimated minimum central pressure is 996 mb (29.42 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: Through Friday, Tropical Storm John is expected to produce additional rainfall amounts of 10 to 20 inches with isolated totals around 30 inches across portions of the Mexican States of Guerrero, Oaxaca and Michoacan. For a complete depiction of forecast rainfall associated with John, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_ep5.shtml?rainqpf STORM SURGE: A dangerous storm surge is expected to produce coastal flooding near and to the east of where the center makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. WIND: Hurricane conditions are expected along the coast within the hurricane warning area Thursday. Winds are expected to first reach tropical storm strength as early as tonight, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. Tropical storm conditions are expected to first reach the coast within the tropical storm warning area as early as tonight. SURF: Swells associated with John are forecast to continue to affect the coast of southern Mexico through the week, with the potential for dangerous surf and rip currents. Please see local statements for more information. NEXT ADVISORY ------------- Next intermediate advisory at 600 PM CST. Next complete advisory at 900 PM CST. $$ Forecaster Bucci/R. Zelinsky

Issued at 400 PM CDT Wed Sep 25 2024 000 WTNT34 KNHC 252107 CCA TCPAT4 BULLETIN Hurricane Helene Advisory Number 10...Corrected NWS National Hurricane Center Miami FL AL092024 400 PM CDT Wed Sep 25 2024 Corrected to remove Storm Surge Watch area in the summary ...HELENE STRENGTHENING... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY FROM STORM SURGE AND DAMAGING WINDS ALONG THE FLORIDA BIG BEND COAST SHOULD BE RUSHED TO COMPLETION TODAY... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...22.5N 86.6W ABOUT 460 MI...735 KM SW OF TAMPA FLORIDA ABOUT 505 MI...815 KM SSW OF APALACHICOLA FLORIDA MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H PRESENT MOVEMENT...N OR 355 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...978 MB...28.88 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Storm Surge Watch east of Mexico Beach to Indian Pass has been upgraded to a Storm Surge Warning. The Tropical Storm Watch north of South Santee River to Little River Inlet has been upgraded to a Tropical Storm Warning. 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 * Cabo Catoche to Tulum, Mexico including Cozumel A Hurricane Watch is in effect for... * Cuban province of Pinar del Rio * 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 * Rio Lagartos to Cabo Catoche, Mexico * Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within the next 36 hours. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 400 PM CDT (2100 UTC), the center of Hurricane Helene was located near latitude 22.5 North, longitude 86.6 West. Helene is moving toward the north near 12 mph (19 km/h). A northward or north-northeastward motion at a faster forward speed is expected during the next 36 hours. On the forecast track, Helene will move across the eastern Gulf of Mexico tonight and Thursday and cross the Florida Big Bend coast Thursday evening. After landfall, Helene is expected to turn northwestward and slow down over the Tennessee Valley on Friday and Saturday. Maximum sustained winds are near 85 mph (140 km/h) with higher gusts. Strengthening is forecast, and Helene is expected to be a major hurricane when it reaches the Florida Big Bend coast Thursday evening. Weakening is expected after landfall, but Helene's fast forward speed will allow strong, damaging winds, especially in gusts, to penetrate well inland across the southeastern United States, including over the higher terrain of the southern Appalachians. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 345 miles (555 km). The estimated minimum central pressure is 978 mb (28.88 inches). HAZARDS AFFECTING LAND ---------------------- Key Messages for Helene can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC and on the web at hurricanes.gov/text/MIATCDAT4.shtml STORM SURGE: The combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Carrabelle, FL to Suwannee River, FL...15-20 ft Apalachicola, FL to Carrabelle, FL...10-15 ft Suwannee River, FL to Chassahowitzka, FL...10-15 ft Chassahowitzka, FL to Anclote River, FL...8-12 ft Indian Pass, FL to Apalachicola, FL...6-10 ft Anclote River, FL to Middle of Longboat Key, FL...5-8 ft Tampa Bay...5-8 ft Middle of Longboat Key, FL to Englewood, FL...4-7 ft East of Mexico Beach, FL to Indian Pass, FL...3-5 ft Englewood, FL to Flamingo, FL...3-5 ft Charlotte Harbor...3-5 ft For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. Storm surge could raise water levels by as much as 2 to 4 feet above normal tide levels in areas of onshore winds along the southern coast of Pinar del Rio, Cuba, including the Isle of Youth. Storm surge could raise water levels by as much as 3 to 5 feet above ground level in areas of onshore winds within the warning area along the north coast of the Yucatan Peninsula. WIND: Hurricane conditions are expected within the U.S. hurricane warning area late Thursday, with tropical storm conditions beginning Thursday morning. Tropical storm conditions are expected in southern Florida later this evening and will spread northward across the rest of Florida, Georgia, and South Carolina through Thursday night. Hurricane conditions, especially in gusts, are expected in the hurricane warning area in Mexico during the next several hours. Tropical storm conditions are occurring in the warning area in Cuba, and hurricane conditions are possible for the western portion of Cuba this evening. RAINFALL: Hurricane Helene is expected to produce total rain accumulations of 4 to 8 inches over western Cuba, the Cayman Islands and the northeast Yucatan Peninsula, with isolated totals around 12 inches. This rainfall brings a risk of considerable flooding. Over portions of the Southeastern U.S. into the Southern Appalachians, Helene is expected to produce total rain accumulations of 6 to 12 inches with isolated totals around 18 inches. This rainfall will likely result in catastrophic and potentially life-threatening flash and urban flooding, along with significant river flooding. Landslides are possible in steep terrain across the southern Appalachians. For a complete depiction of forecast rainfall associated with Hurricane Helene, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero. TORNADOES: A tornado or two may occur tonight over parts of the Florida Peninsula and southern Alabama. The risk of tornadoes will increase on Thursday, expanding northward across Florida into parts of Georgia and South Carolina. SURF: Swells generated by Helene will affect the southern coast of Cuba and the Yucatan Peninsula of Mexico during the next couple of days. Swells will spread northward toward the west coast of Florida and the northeastern Gulf Coast later today and Thursday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 700 PM CDT. Next complete advisory at 1000 PM CDT. $$ Forecaster Berg

...HELENE STRENGTHENING... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY FROM STORM SURGE AND DAMAGING WINDS ALONG THE FLORIDA BIG BEND COAST SHOULD BE RUSHED TO COMPLETION TODAY... As of 4:00 PM CDT Wed Sep 25 the center of Helene was located near 22.5, -86.6 with movement N at 12 mph. The minimum central pressure was 978 mb with maximum sustained winds of about 85 mph.

5-Day Uncertainty Track last updated Wed, 25 Sep 2024 21:02:47 GMT


Wind Speed Probabilities last updated Wed, 25 Sep 2024 21:23:12 GMT

Storm Surge Watch/Warning Map last updated Wed, 25 Sep 2024 20:59:22 GMT

Issued at 2100 UTC WED SEP 25 2024 000 WTNT24 KNHC 252055 TCMAT4 HURRICANE HELENE FORECAST/ADVISORY NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 2100 UTC WED SEP 25 2024 HURRICANE CENTER LOCATED NEAR 22.5N 86.6W AT 25/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTH OR 355 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 978 MB MAX SUSTAINED WINDS 75 KT WITH GUSTS TO 90 KT. 64 KT....... 20NE 20SE 0SW 0NW. 50 KT....... 60NE 60SE 40SW 40NW. 34 KT.......210NE 300SE 90SW 120NW. 12 FT SEAS..180NE 210SE 90SW 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 22.5N 86.6W AT 25/2100Z AT 25/1800Z CENTER WAS LOCATED NEAR 22.0N 86.4W FORECAST VALID 26/0600Z 24.1N 86.2W MAX WIND 95 KT...GUSTS 115 KT. 64 KT... 30NE 40SE 25SW 20NW. 50 KT... 80NE 80SE 50SW 40NW. 34 KT...270NE 270SE 120SW 120NW. FORECAST VALID 26/1800Z 27.4N 85.2W MAX WIND 115 KT...GUSTS 140 KT. 64 KT... 40NE 50SE 25SW 20NW. 50 KT... 80NE 100SE 50SW 40NW. 34 KT...270NE 270SE 140SW 140NW. FORECAST VALID 27/0600Z 32.1N 84.6W...INLAND MAX WIND 70 KT...GUSTS 90 KT. 64 KT... 20NE 25SE 0SW 0NW. 50 KT... 40NE 50SE 20SW 20NW. 34 KT...270NE 270SE 70SW 60NW. FORECAST VALID 27/1800Z 36.1N 86.0W...POST-TROP/EXTRATROP MAX WIND 35 KT...GUSTS 55 KT. 34 KT... 50NE 30SE 0SW 0NW. FORECAST VALID 28/0600Z 37.1N 88.1W...POST-TROP/EXTRATROP MAX WIND 25 KT...GUSTS 40 KT. FORECAST VALID 28/1800Z 36.8N 88.7W...POST-TROP/EXTRATROP MAX WIND 20 KT...GUSTS 30 KT. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 29/1800Z 37.0N 88.0W...POST-TROP/EXTRATROP MAX WIND 15 KT...GUSTS 20 KT. OUTLOOK VALID 30/1800Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.5N 86.6W INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 26/0000Z NEXT ADVISORY AT 26/0300Z $$ FORECASTER BERG

Issued at 400 PM CDT Wed Sep 25 2024 000 WTNT44 KNHC 252056 TCDAT4 Hurricane Helene Discussion Number 10 NWS National Hurricane Center Miami FL AL092024 400 PM CDT Wed Sep 25 2024 A ragged eye is becoming apparent in visible satellite imagery and has also been observed in recent radar data from Cancun and western Cuba. Based on the improved structure, the initial intensity is set at 75 kt, which is at the high end of the satellite intensity estimates. This is also supported by the earlier Air Force Reserve reconnaissance mission, which measured a peak 700-mb flight-level wind of 81 kt. Helene has turned northward (355/9 kt) and is expected to accelerate toward the north or north-northeast during the next 24-36 hours as it moves across the Gulf of Mexico and crosses the Florida Big Bend coast Thursday evening. After landfall, the system is forecast to interact with a deep-layer trough to the west and turn northwestward with a decrease in speed over the Tennessee Valley. The environment appears primed for significant strengthening while Helene moves across the Gulf of Mexico. The forecast track more or less runs along the axis of the Loop Current during the next 24 hours, where ocean temperatures are about 30 degrees Celsius. In addition, Helene will be moving through an environment of low vertical shear and strong upper-level divergence. Some of the Rapid Intensification (RI) indices, particular DTOPS, respond to this environment by indicating at least a 90 percent chance of a 35-kt increase in intensity over the next 24 hours. The NHC intensity forecast now shows an intensity of 115 kt (Category 4) at 24 hours, which is mirrored by several of the regional hurricane models and the SHIPS guidance. It should be noted that additional strengthening is possible beyond 24 hours before Helene makes landfall Thursday evening. Helene is forecast to be a large major hurricane when it reaches the Big Bend coast of Florida. As a result, storm surge, wind, and rainfall impacts will extend well away from the center and outside the forecast cone, particularly on the east side. In addition, the fast forward speed when Helene moves inland will result in a far inland penetration of strong winds over parts of the southeastern United States, including strong gusts over higher terrain of the southern Appalachians. A higher-than-normal gust factor has been 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 late Thursday. Preparations to protect life and property should be completed by early Thursday before tropical storm conditions arrive. Damaging and life-threatening hurricane-force winds, especially in gusts, will penetrate well inland over portions of northern Florida and southern Georgia late Thursday and Thursday night 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 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 minor to moderate river flooding is likely, and isolated major river flooding is possible. 4. Hurricane and tropical storm conditions are expected over northeastern portions of the Yucatan Peninsula of Mexico this evening where Tropical Storm and Hurricane Warnings are in effect. Tropical storm conditions are occurring over portions of western Cuba within the Tropical Storm Warning area, and hurricane conditions are possible this evening within the Hurricane Watch area. Helene will bring heavy rain to portions of the western Caribbean with potentially significant flooding across western Cuba and the northeastern Yucatan Peninsula into early Thursday. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 22.5N 86.6W 75 KT 85 MPH 12H 26/0600Z 24.1N 86.2W 95 KT 110 MPH 24H 26/1800Z 27.4N 85.2W 115 KT 130 MPH 36H 27/0600Z 32.1N 84.6W 70 KT 80 MPH...INLAND 48H 27/1800Z 36.1N 86.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 60H 28/0600Z 37.1N 88.1W 25 KT 30 MPH...POST-TROP/EXTRATROP 72H 28/1800Z 36.8N 88.7W 20 KT 25 MPH...POST-TROP/EXTRATROP 96H 29/1800Z 37.0N 88.0W 15 KT 15 MPH...POST-TROP/EXTRATROP 120H 30/1800Z...DISSIPATED $$ Forecaster Berg

Issued at 2100 UTC WED SEP 25 2024 000 FONT14 KNHC 252056 PWSAT4 HURRICANE HELENE WIND SPEED PROBABILITIES NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 2100 UTC WED SEP 25 2024 AT 2100Z THE CENTER OF HURRICANE HELENE WAS LOCATED NEAR LATITUDE 22.5 NORTH...LONGITUDE 86.6 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 75 KTS...85 MPH...140 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 18Z WED 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 18Z WED 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN PERIODS TO TO TO TO TO TO TO 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN 18Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CHARLOTTE NC 34 X X( X) 3( 3) 1( 4) X( 4) X( 4) X( 4) FLORENCE SC 34 X X( X) 3( 3) 1( 4) X( 4) X( 4) X( 4) COLUMBIA SC 34 X X( X) 7( 7) 1( 8) X( 8) X( 8) X( 8) LITTLE RIVER 34 X X( X) 3( 3) 1( 4) X( 4) X( 4) X( 4) MYRTLE BEACH 34 X X( X) 5( 5) 1( 6) X( 6) X( 6) X( 6) GEORGETOWN SC 34 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) CHARLESTON SC 34 X X( X) 15(15) 1(16) X(16) X(16) X(16) BEAUFORT MCAS 34 X X( X) 27(27) 2(29) X(29) X(29) X(29) ATLANTA GA 34 X X( X) 33(33) 36(69) X(69) X(69) X(69) AUGUSTA GA 34 X X( X) 18(18) 3(21) X(21) X(21) X(21) SAVANNAH GA 34 X X( X) 16(16) 1(17) X(17) X(17) X(17) KINGS BAY GA 34 X 8( 8) 43(51) 1(52) X(52) X(52) X(52) KINGS BAY GA 50 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) WAYCROSS GA 34 X 6( 6) 52(58) 1(59) X(59) X(59) X(59) WAYCROSS GA 50 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) MAYPORT NS FL 34 X 9( 9) 40(49) 1(50) X(50) X(50) X(50) MAYPORT NS FL 50 X X( X) 3( 3) X( 3) X( 3) X( 3) X( 3) JACKSONVILLE 34 X 7( 7) 31(38) X(38) X(38) X(38) X(38) GAINESVILLE FL 34 X 18(18) 46(64) X(64) X(64) X(64) X(64) GAINESVILLE FL 50 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) DAYTONA BEACH 34 X 9( 9) 14(23) X(23) X(23) X(23) X(23) THE VILLAGES 34 X 27(27) 26(53) X(53) X(53) X(53) X(53) ORLANDO FL 34 X 17(17) 12(29) X(29) X(29) X(29) X(29) COCOA BEACH FL 34 X 18(18) 13(31) X(31) X(31) X(31) X(31) PATRICK AFB 34 X 19(19) 13(32) X(32) X(32) X(32) X(32) FT PIERCE FL 34 X 16(16) 7(23) X(23) X(23) X(23) X(23) W PALM BEACH 34 X 12(12) 2(14) X(14) X(14) X(14) X(14) FT LAUDERDALE 34 X 11(11) 1(12) X(12) X(12) X(12) X(12) MIAMI FL 34 X 7( 7) X( 7) X( 7) X( 7) X( 7) X( 7) HOMESTEAD ARB 34 X 7( 7) X( 7) X( 7) X( 7) X( 7) X( 7) MARATHON FL 34 7 15(22) X(22) X(22) X(22) X(22) X(22) KEY WEST FL 34 19 24(43) X(43) X(43) X(43) X(43) X(43) NAPLES FL 34 8 44(52) 2(54) X(54) X(54) X(54) X(54) FT MYERS FL 34 5 40(45) 1(46) X(46) X(46) X(46) X(46) VENICE FL 34 8 66(74) 4(78) X(78) X(78) X(78) X(78) VENICE FL 50 X 7( 7) 1( 8) X( 8) X( 8) X( 8) X( 8) TAMPA FL 34 2 65(67) 12(79) X(79) X(79) X(79) X(79) TAMPA FL 50 X 6( 6) 4(10) X(10) X(10) X(10) X(10) TAMPA FL 64 X X( X) 1( 1) X( 1) X( 1) X( 1) X( 1) CEDAR KEY FL 34 X 57(57) 31(88) X(88) X(88) X(88) X(88) CEDAR KEY FL 50 X 6( 6) 19(25) X(25) X(25) X(25) X(25) CEDAR KEY FL 64 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) TALLAHASSEE FL 34 X 16(16) 81(97) X(97) X(97) X(97) X(97) TALLAHASSEE FL 50 X 1( 1) 64(65) 1(66) X(66) X(66) X(66) TALLAHASSEE FL 64 X X( X) 25(25) 1(26) X(26) X(26) X(26) ST MARKS FL 34 X 24(24) 74(98) X(98) X(98) X(98) X(98) ST MARKS FL 50 X 2( 2) 62(64) X(64) X(64) X(64) X(64) ST MARKS FL 64 X X( X) 29(29) X(29) X(29) X(29) X(29) APALACHICOLA 34 X 53(53) 45(98) X(98) X(98) X(98) X(98) APALACHICOLA 50 X 9( 9) 80(89) X(89) X(89) X(89) X(89) APALACHICOLA 64 X 1( 1) 61(62) X(62) X(62) X(62) X(62) GFMX 290N 850W 34 3 74(77) 22(99) X(99) X(99) X(99) X(99) GFMX 290N 850W 50 X 27(27) 66(93) X(93) X(93) X(93) X(93) GFMX 290N 850W 64 X 6( 6) 65(71) X(71) X(71) X(71) X(71) PANAMA CITY FL 34 X 35(35) 55(90) X(90) X(90) X(90) X(90) PANAMA CITY FL 50 X 4( 4) 62(66) X(66) X(66) X(66) X(66) PANAMA CITY FL 64 X X( X) 31(31) X(31) X(31) X(31) X(31) DESTIN EXEC AP 34 X 9( 9) 38(47) X(47) X(47) X(47) X(47) DESTIN EXEC AP 50 X 1( 1) 8( 9) X( 9) X( 9) X( 9) X( 9) DESTIN EXEC AP 64 X X( X) 1( 1) 1( 2) X( 2) X( 2) X( 2) ALBANY GA 34 X 7( 7) 85(92) 1(93) X(93) X(93) X(93) ALBANY GA 50 X X( X) 45(45) 1(46) X(46) X(46) X(46) ALBANY GA 64 X X( X) 2( 2) 1( 3) X( 3) X( 3) X( 3) COLUMBUS GA 34 X 2( 2) 69(71) 8(79) X(79) X(79) X(79) COLUMBUS GA 50 X X( X) 10(10) 3(13) X(13) X(13) X(13) MACON GA 34 X 1( 1) 66(67) 8(75) X(75) X(75) X(75) MACON GA 50 X X( X) 6( 6) 4(10) X(10) X(10) X(10) DOTHAN AL 34 X 7( 7) 76(83) X(83) X(83) X(83) X(83) DOTHAN AL 50 X X( X) 37(37) X(37) X(37) X(37) X(37) DOTHAN AL 64 X X( X) 3( 3) 1( 4) X( 4) X( 4) X( 4) BIRMINGHAM AL 34 X X( X) 6( 6) 7(13) X(13) X(13) X(13) MONTGOMERY AL 34 X 2( 2) 22(24) 4(28) X(28) X(28) X(28) MONTGOMERY AL 50 X X( X) 2( 2) 1( 3) X( 3) X( 3) X( 3) WHITING FLD FL 34 X 7( 7) 14(21) X(21) X(21) X(21) X(21) WHITING FLD FL 50 X X( X) 3( 3) X( 3) X( 3) X( 3) X( 3) PENSACOLA FL 34 X 7( 7) 11(18) X(18) X(18) X(18) X(18) GFMX 290N 870W 34 3 32(35) 17(52) X(52) X(52) X(52) X(52) GFMX 290N 870W 50 X 5( 5) 7(12) X(12) X(12) X(12) X(12) GFMX 290N 870W 64 X X( X) 2( 2) X( 2) X( 2) X( 2) X( 2) MOBILE AL 34 X 4( 4) 3( 7) X( 7) X( 7) X( 7) X( 7) GULFPORT MS 34 X 4( 4) 2( 6) X( 6) X( 6) X( 6) X( 6) STENNIS MS 34 X 3( 3) 2( 5) X( 5) X( 5) X( 5) X( 5) BURAS LA 34 X 5( 5) 1( 6) X( 6) X( 6) X( 6) X( 6) GFMX 280N 890W 34 5 5(10) 2(12) X(12) X(12) X(12) X(12) NEW ORLEANS LA 34 X 1( 1) 2( 3) X( 3) X( 3) X( 3) X( 3) GFMX 280N 910W 34 X 2( 2) 1( 3) X( 3) X( 3) X( 3) X( 3) MERIDA MX 34 4 X( 4) X( 4) X( 4) X( 4) X( 4) X( 4) COZUMEL MX 34 99 X(99) X(99) X(99) X(99) X(99) X(99) CP SAN ANTONIO 34 99 X(99) X(99) X(99) X(99) X(99) X(99) CP SAN ANTONIO 50 4 X( 4) X( 4) X( 4) X( 4) X( 4) X( 4) HAVANA 34 28 6(34) X(34) X(34) X(34) X(34) X(34) ISLE OF PINES 34 99 X(99) X(99) X(99) X(99) X(99) X(99) $$ FORECASTER BERG

5-Day Uncertainty Track last updated Wed, 25 Sep 2024 20:53:54 GMT


Wind Speed Probabilities last updated Wed, 25 Sep 2024 21:29:01 GMT

Issued at 2100 UTC WED SEP 25 2024 000 FOPZ15 KNHC 252052 PWSEP5 TROPICAL STORM JOHN WIND SPEED PROBABILITIES NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102024 2100 UTC WED SEP 25 2024 AT 2100Z THE CENTER OF TROPICAL STORM JOHN WAS LOCATED NEAR LATITUDE 16.8 NORTH...LONGITUDE 101.5 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 45 KTS...50 MPH...85 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 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 18Z WED 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 18Z WED 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN PERIODS TO TO TO TO TO TO TO 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN 18Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 15N 105W 34 4 2( 6) 1( 7) X( 7) X( 7) X( 7) X( 7) MANZANILLO 34 4 2( 6) 1( 7) 1( 8) X( 8) X( 8) X( 8) L CARDENAS 34 33 15(48) 4(52) 2(54) X(54) X(54) X(54) L CARDENAS 50 1 6( 7) 4(11) 2(13) X(13) X(13) X(13) L CARDENAS 64 X 1( 1) 1( 2) 1( 3) X( 3) X( 3) X( 3) ZIHUATANEJO 34 56 15(71) 5(76) X(76) X(76) X(76) X(76) ZIHUATANEJO 50 11 17(28) 4(32) 1(33) X(33) X(33) X(33) ZIHUATANEJO 64 1 5( 6) 2( 8) X( 8) X( 8) X( 8) X( 8) 15N 100W 34 23 4(27) 1(28) X(28) X(28) X(28) X(28) ACAPULCO 34 44 8(52) 1(53) X(53) X(53) X(53) X(53) P MALDONADO 34 10 4(14) 1(15) X(15) X(15) X(15) X(15) $$ FORECASTER BUCCI

Issued at 300 PM CST Wed Sep 25 2024 000 WTPZ45 KNHC 252052 TCDEP5 Tropical Storm John Discussion Number 12 NWS National Hurricane Center Miami FL EP102024 300 PM CST Wed Sep 25 2024 John is becoming more organized this afternoon. Satellite imagery has shown deep bursts of convection forming near the center with curved banding around the majority of the circulation. Subjective Dvorak from TAFB and SAB were 3.5/55 kt and 2.5/35 kt, respectively, and the initial intensity for this advisory is set to 45 kt to represent a blend of these estimates. An Air Force Hurricane Reconnaissance aircraft is en route to investigate John and gather more information about the intensity, location, and structure. The tropical-storm-force winds in the southeast quadrant have been adjusted outward significantly based on an earlier partial ASCAT pass. Little has changed in the intensity forecast reasoning. Oceanic and atmospheric conditions are conducive for further intensification, as long as the storm remains over water. SHIPS-RII, a rapid intensification indicator, shows about a 70 percent chance of rapid intensification in the next 24 hours. The official intensity forecast now shows John becoming a hurricane in 24 hours as it nears the coast of southwestern Mexico. This forecast is near the top of the guidance, closest to HCCA, but could still be conservative. John is moving with an estimated motion of 355/3 kt. The track forecast is rather uncertain. Model guidance has shifted westward, and is showing John either nearly stationary or slowly following the coastline northwestward. This motion seems to depend on the strength of the ridge to the north-northwest, which is centered over the southwestern United States. However, the current motion suggests John should move closer to the coast with the center likely to move inland on Thursday afternoon or evening, though this could occur sooner. Future adjustments to the track forecast may be necessary, and there remains a large spread in the aids. A Hurricane Warning has been issued by the government of Mexico for portions of the coast of southwestern Mexico, and interests there should closely monitor future forecasts for updates. The Tropical Storm Warning and Hurricane Watch have also been extended westward. KEY MESSAGES: 1. Tropical Storm John will bring additional very heavy rainfall to coastal portions of southwest Mexico through Friday. The additional rainfall totals will be falling across areas that have received very heavy rainfall amounts over the past few days. This heavy rainfall will likely cause significant and catastrophic life-threatening flash flooding and mudslides to the Mexican States of Guerrero, Oaxaca and Michoacan. 2. John is forecast to strengthen to a hurricane before landfall, and a Hurricane Warning has been issued for a portion of the coastline of southwestern Mexico, where tropical storm conditions could begin later today. The Tropical Storm Warning and Hurricane Watch have also been extended westward. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 16.8N 101.5W 45 KT 50 MPH 12H 26/0600Z 17.1N 101.5W 60 KT 70 MPH 24H 26/1800Z 17.5N 101.5W 65 KT 75 MPH 36H 27/0600Z 18.0N 101.6W 40 KT 45 MPH...INLAND 48H 27/1800Z 18.2N 102.1W 25 KT 30 MPH...INLAND 60H 28/0600Z...DISSIPATED $$ Forecaster Bucci/R. Zelinsky

...JOHN EXPECTED TO BECOME A HURRICANE... ...HURRICANE WARNING ISSUED FOR SOUTHWESTERN MEXICO... As of 3:00 PM CST Wed Sep 25 the center of John was located near 16.8, -101.5 with movement N at 3 mph. The minimum central pressure was 996 mb with maximum sustained winds of about 50 mph.

Issued at 2100 UTC WED SEP 25 2024 740 WTPZ25 KNHC 252051 TCMEP5 TROPICAL STORM JOHN FORECAST/ADVISORY NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102024 2100 UTC WED SEP 25 2024 TROPICAL STORM CENTER LOCATED NEAR 16.8N 101.5W AT 25/2100Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE NORTH OR 355 DEGREES AT 3 KT ESTIMATED MINIMUM CENTRAL PRESSURE 996 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT....... 40NE 130SE 100SW 0NW. 12 FT SEAS.. 0NE 240SE 210SW 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 16.8N 101.5W AT 25/2100Z AT 25/1800Z CENTER WAS LOCATED NEAR 16.7N 101.5W FORECAST VALID 26/0600Z 17.1N 101.5W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 20NE 30SE 0SW 0NW. 34 KT... 50NE 140SE 110SW 20NW. FORECAST VALID 26/1800Z 17.5N 101.5W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 0NE 25SE 0SW 0NW. 50 KT... 30NE 50SE 30SW 0NW. 34 KT... 70NE 140SE 110SW 40NW. FORECAST VALID 27/0600Z 18.0N 101.6W...INLAND MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 0NE 90SE 60SW 0NW. FORECAST VALID 27/1800Z 18.2N 102.1W...INLAND MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 28/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.8N 101.5W INTERMEDIATE PUBLIC ADVISORY...WTNT35 KNHC/MIATCPEP5...AT 26/0000Z NEXT ADVISORY AT 26/0300Z $$ FORECASTER BUCCI/R. ZELINSKY

Some boat owners in Ohio were warned to remove their boats from the water early as drought has lowered lake levels. The owner of a boat sales, service and storage facility has urged customers to take their vessels out of Tappan and Seneca lakes early. Some people with cottages and private docks at Leesville Lake have also been advised to remove their boats before the low water level leaves them stuck in the lake during winter. The Daily Jeff (Cambridge, Ohio), Sept 25, 2024

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more