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Hurricane Helene Forecast Discussion Number 11
2024-09-26 04:55:08| National Hurricane Center (Atlantic)
Issued at 1000 PM CDT Wed Sep 25 2024 000 WTNT44 KNHC 260255 TCDAT4 Hurricane Helene Discussion Number 11 NWS National Hurricane Center Miami FL AL092024 1000 PM CDT Wed Sep 25 2024 Satellite images show that Helene has a well-organized appearance, with numerous convective banding features. A ragged-looking eye feature is also apparent. However, reports from both Air Force and a NOAA Hurricane Hunter aircraft investigating the system suggest that the it lacks a well-defined inner core with a somewhat broad maximum wind field for now. The central pressure has dropped a little to around 972 mb. Given the slowly falling central pressure, the intensity is maintained at 75 kt for this advisory. Helene's structure and intensity will continue to be closely monitored by Hurricane Hunter aircraft tonight and Thursday. The hurricane continues moving northward with an estimated initial motion of 360/08 kt. For the next couple of days, the steering scenario for this system remains basically unchanged from the earlier advisory. The flow between a mid-tropospheric trough over the east-central United States and a ridge over the western Atlantic should result in Helene accelerating northward to north-northeastward during the next 24 to 36 hours. This motion will bring the center of Helene to the northeastern Gulf of Mexico coast in about 24 hours. The official track forecast through landfall is very similar to the previous NHC prediction and remains close to the corrected consensus guidance. After landfall, the trough to the northwest of the tropical cyclone becomes a cutoff low, and Helene should turn leftward as it rotates around the low. In 3-4 days, the system should become a shallow extratropical cyclone within weaker steering currents. Helene should be in an atmospheric and oceanic environment over the eastern Gulf of Mexico that will be very conducive for strengthening. The system is expected to traverse the Loop Current, which has especially high oceanic heat content. This, along with fairly low vertical wind shear and a moist mid- to lower- tropospheric air mass, should likely result in rapid intensification before landfall. The official forecast continues to call for the hurricane to reach category 4 status tomorrow. It should be noted that the HAFS-A and HAFS-B regional hurricane models show even more intensification than indicated here. 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 is indicated in the official forecast while Helene is inland. KEY MESSAGES: 1. A catastrophic and deadly storm surge is likely along portions of the Florida Big Bend coast, where inundation could reach as high as 20 feet above ground level, along with destructive waves. There is also a danger of life-threatening storm surge along the remainder of the west coast of the Florida Peninsula. Residents in those areas should follow advice given by local officials and evacuate if told to do so. 2. Potentially catastrophic hurricane-force winds are expected within the eyewall of Helene when it makes landfall in the Florida Big Bend region 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 numerous 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 and isolated major river flooding are likely. 4. Tropical storm conditions are expected over portions of western Cuba within the Tropical Storm Warning area. Hurricane Helene will bring heavy rain to portions of the western Caribbean with potentially significant flooding across western Cuba and the northeastern Yucatan Peninsula into early Thursday. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 23.1N 86.6W 75 KT 85 MPH 12H 26/1200Z 25.4N 86.1W 95 KT 110 MPH 24H 27/0000Z 29.5N 84.5W 115 KT 130 MPH 36H 27/1200Z 34.3N 84.7W 50 KT 60 MPH...INLAND 48H 28/0000Z 36.7N 87.1W 30 KT 35 MPH...POST-TROP/EXTRATROP 60H 28/1200Z 36.8N 88.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 72H 29/0000Z 36.7N 87.0W 20 KT 25 MPH...POST-TROP/EXTRATROP 96H 30/0000Z 36.7N 84.9W 15 KT 15 MPH...POST-TROP/EXTRATROP 120H 01/0000Z...DISSIPATED $$ Forecaster Pasch
Category:Transportation and Logistics
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Hurricane Helene Wind Speed Probabilities Number 11
2024-09-26 04:54:38| National Hurricane Center (Atlantic)
Issued at 0300 UTC THU SEP 26 2024 000 FONT14 KNHC 260254 PWSAT4 HURRICANE HELENE WIND SPEED PROBABILITIES NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024 0300 UTC THU SEP 26 2024 AT 0300Z THE CENTER OF HURRICANE HELENE WAS LOCATED NEAR LATITUDE 23.1 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 00Z THU AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 00Z THU 12Z THU 00Z FRI 12Z FRI 00Z SAT 00Z SUN 00Z MON PERIODS TO TO TO TO TO TO TO 12Z THU 00Z FRI 12Z FRI 00Z SAT 00Z SUN 00Z MON 00Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT CHARLOTTE NC 34 X X( X) 6( 6) X( 6) X( 6) X( 6) X( 6) FLORENCE SC 34 X X( X) 5( 5) X( 5) X( 5) X( 5) X( 5) COLUMBIA SC 34 X 1( 1) 8( 9) X( 9) X( 9) X( 9) X( 9) LITTLE RIVER 34 X X( X) 4( 4) X( 4) X( 4) X( 4) X( 4) MYRTLE BEACH 34 X X( X) 7( 7) X( 7) X( 7) X( 7) X( 7) GEORGETOWN SC 34 X X( X) 5( 5) X( 5) X( 5) X( 5) X( 5) CHARLESTON SC 34 X 5( 5) 17(22) X(22) X(22) X(22) X(22) BEAUFORT MCAS 34 X 11(11) 24(35) X(35) X(35) X(35) X(35) ATLANTA GA 34 X 5( 5) 71(76) 2(78) X(78) X(78) X(78) AUGUSTA GA 34 X 5( 5) 27(32) X(32) X(32) X(32) X(32) SAVANNAH GA 34 X 9( 9) 19(28) X(28) X(28) X(28) X(28) KINGS BAY GA 34 X 50(50) 15(65) X(65) X(65) X(65) X(65) KINGS BAY GA 50 X 3( 3) 2( 5) X( 5) X( 5) X( 5) X( 5) WAYCROSS GA 34 X 47(47) 30(77) X(77) X(77) X(77) X(77) WAYCROSS GA 50 X 2( 2) 4( 6) X( 6) X( 6) X( 6) X( 6) MAYPORT NS FL 34 X 53(53) 11(64) X(64) X(64) X(64) X(64) MAYPORT NS FL 50 X 3( 3) 1( 4) X( 4) X( 4) X( 4) X( 4) JACKSONVILLE 34 X 51(51) 12(63) X(63) X(63) X(63) X(63) JACKSONVILLE 50 X 2( 2) 1( 3) X( 3) X( 3) X( 3) X( 3) GAINESVILLE FL 34 1 84(85) 2(87) X(87) X(87) X(87) X(87) GAINESVILLE FL 50 X 7( 7) 1( 8) X( 8) X( 8) X( 8) X( 8) DAYTONA BEACH 34 X 44(44) 1(45) X(45) X(45) X(45) X(45) THE VILLAGES 34 2 76(78) X(78) X(78) X(78) X(78) X(78) THE VILLAGES 50 X 4( 4) 1( 5) X( 5) X( 5) X( 5) X( 5) ORLANDO FL 34 1 49(50) X(50) X(50) X(50) X(50) X(50) COCOA BEACH FL 34 X 41(41) 1(42) X(42) X(42) X(42) X(42) PATRICK AFB 34 X 41(41) 1(42) X(42) X(42) X(42) X(42) FT PIERCE FL 34 X 29(29) 1(30) X(30) X(30) X(30) X(30) W PALM BEACH 34 X 16(16) 1(17) X(17) X(17) X(17) X(17) FT LAUDERDALE 34 X 11(11) X(11) X(11) X(11) X(11) X(11) MIAMI FL 34 1 5( 6) X( 6) X( 6) X( 6) X( 6) X( 6) HOMESTEAD ARB 34 1 5( 6) X( 6) X( 6) X( 6) X( 6) X( 6) MARATHON FL 34 11 10(21) X(21) X(21) X(21) X(21) X(21) KEY WEST FL 34 27 16(43) X(43) X(43) X(43) X(43) X(43) NAPLES FL 34 21 37(58) X(58) X(58) X(58) X(58) X(58) FT MYERS FL 34 8 47(55) X(55) X(55) X(55) X(55) X(55) VENICE FL 34 26 56(82) X(82) X(82) X(82) X(82) X(82) VENICE FL 50 X 7( 7) X( 7) X( 7) X( 7) X( 7) X( 7) TAMPA FL 34 13 72(85) X(85) X(85) X(85) X(85) X(85) TAMPA FL 50 X 12(12) X(12) X(12) X(12) X(12) X(12) TAMPA FL 64 X 2( 2) X( 2) X( 2) X( 2) X( 2) X( 2) CEDAR KEY FL 34 7 88(95) 1(96) X(96) X(96) X(96) X(96) CEDAR KEY FL 50 X 41(41) 1(42) X(42) X(42) X(42) X(42) CEDAR KEY FL 64 X 9( 9) 1(10) X(10) X(10) X(10) X(10) TALLAHASSEE FL 34 1 93(94) 5(99) X(99) X(99) X(99) X(99) TALLAHASSEE FL 50 X 43(43) 41(84) X(84) X(84) X(84) X(84) TALLAHASSEE FL 64 X 9( 9) 44(53) X(53) X(53) X(53) X(53) ST MARKS FL 34 2 95(97) 2(99) X(99) X(99) X(99) X(99) ST MARKS FL 50 X 62(62) 22(84) X(84) X(84) X(84) X(84) ST MARKS FL 64 X 25(25) 31(56) X(56) X(56) X(56) X(56) APALACHICOLA 34 7 90(97) 1(98) X(98) X(98) X(98) X(98) APALACHICOLA 50 X 81(81) 5(86) X(86) X(86) X(86) X(86) APALACHICOLA 64 X 44(44) 10(54) X(54) X(54) X(54) X(54) GFMX 290N 850W 34 11 88(99) X(99) X(99) X(99) X(99) X(99) GFMX 290N 850W 50 X 92(92) 1(93) X(93) X(93) X(93) X(93) GFMX 290N 850W 64 X 67(67) 1(68) X(68) X(68) X(68) X(68) PANAMA CITY FL 34 5 80(85) 3(88) X(88) X(88) X(88) X(88) PANAMA CITY FL 50 X 40(40) 12(52) X(52) X(52) X(52) X(52) PANAMA CITY FL 64 X 8( 8) 9(17) X(17) X(17) X(17) X(17) DESTIN EXEC AP 34 2 30(32) 7(39) X(39) X(39) X(39) X(39) DESTIN EXEC AP 50 X 3( 3) 2( 5) X( 5) X( 5) X( 5) X( 5) ALBANY GA 34 X 54(54) 42(96) X(96) X(96) X(96) X(96) ALBANY GA 50 X 3( 3) 62(65) X(65) X(65) X(65) X(65) ALBANY GA 64 X X( X) 25(25) X(25) X(25) X(25) X(25) COLUMBUS GA 34 X 9( 9) 77(86) X(86) X(86) X(86) X(86) COLUMBUS GA 50 X X( X) 29(29) X(29) X(29) X(29) X(29) MACON GA 34 X 8( 8) 80(88) X(88) X(88) X(88) X(88) MACON GA 50 X X( X) 21(21) X(21) X(21) X(21) X(21) DOTHAN AL 34 X 48(48) 36(84) X(84) X(84) X(84) X(84) DOTHAN AL 50 X 3( 3) 36(39) X(39) X(39) X(39) X(39) DOTHAN AL 64 X X( X) 10(10) X(10) X(10) X(10) X(10) BIRMINGHAM AL 34 X 3( 3) 6( 9) X( 9) X( 9) X( 9) X( 9) MONTGOMERY AL 34 X 6( 6) 22(28) X(28) X(28) X(28) X(28) WHITING FLD FL 34 1 10(11) 7(18) X(18) X(18) X(18) X(18) PENSACOLA FL 34 1 10(11) 3(14) X(14) X(14) X(14) X(14) GFMX 290N 870W 34 8 37(45) 1(46) X(46) X(46) X(46) X(46) GFMX 290N 870W 50 X 8( 8) X( 8) X( 8) X( 8) X( 8) X( 8) MOBILE AL 34 X 6( 6) 1( 7) X( 7) X( 7) X( 7) X( 7) GULFPORT MS 34 X 6( 6) X( 6) X( 6) X( 6) X( 6) X( 6) STENNIS MS 34 X 5( 5) X( 5) X( 5) X( 5) X( 5) X( 5) BURAS LA 34 2 4( 6) X( 6) X( 6) X( 6) X( 6) X( 6) GFMX 280N 890W 34 6 4(10) X(10) X(10) X(10) X(10) X(10) NEW ORLEANS LA 34 X 3( 3) X( 3) X( 3) X( 3) X( 3) X( 3) GFMX 280N 910W 34 2 1( 3) X( 3) X( 3) X( 3) X( 3) X( 3) MERIDA MX 34 3 X( 3) X( 3) X( 3) X( 3) X( 3) X( 3) 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) HAVANA 34 20 1(21) X(21) X(21) X(21) X(21) X(21) ISLE OF PINES 34 24 X(24) X(24) X(24) X(24) X(24) X(24) $$ FORECASTER PASCH
Category: Transportation and Logistics
Summary for Hurricane Helene (AT4/AL092024)
2024-09-26 04:54:08| National Hurricane Center (Atlantic)
...HELENE EXPECTED TO BRING CATASTROPHIC WINDS AND STORM SURGES TO THE NORTHEASTERN GULF COAST... ...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION... As of 10:00 PM CDT Wed Sep 25 the center of Helene was located near 23.1, -86.6 with movement N at 9 mph. The minimum central pressure was 972 mb with maximum sustained winds of about 85 mph.
Category: Transportation and Logistics