5-Day Uncertainty Track last updated Sat, 28 Sep 2024 08:36:40 GMT

5-Day Uncertainty Track last updated Sat, 28 Sep 2024 08:43:07 GMT


Wind Speed Probabilities last updated Sat, 28 Sep 2024 09:23:15 GMT

Issued at 900 AM GMT Sat Sep 28 2024 000 WTNT45 KNHC 280840 TCDAT5 Hurricane Isaac Discussion Number 10 NWS National Hurricane Center Miami FL AL102024 900 AM GMT Sat Sep 28 2024 Isaac has continued to strengthen this morning. The satellite presentation consists of a 20 nm (WMG 8C) clear eye and an impressive curve band in the north side of the cyclone beneath the upper diffluent westerlies. The initial intensity is bumped up to 90 kt for this advisory and is based on a UW-CIMSS SATCON analysis of 93 kt and the Dvorak intensity estimates for TAFB and SAB. Some fluctuations in strength are possible during the day, after which Isaac will be traversing cooler oceanic surface temperatures and experiencing increasing deep-layer shear. Subsequently, gradual weakening is forecast, and the cyclone is expected to lose its deep core convection and become a post-tropical cyclone in 48 hrs. After that time, the global model fields and the FSU Cyclone Phase Evolution forecast show Isaac transitioning from a symmetric warm-core system to an asymmetric cold-core, more frontal thermal structure. The NHC intensity forecast is similar to the consensus aids and shows Isaac completing its extratropical cyclone transition by Tuesday. Isaac has turned toward the northeast, or 055/17 kt, in response to a mid-latitude shortwave ridge temporarily building to the north of the cyclone. By early next week, as Isaac loses its tropical characteristics and completes an extratropical transition, the cyclone should turn toward the north-northeast while a major shortwave trough approaches from the northwest over the central Atlantic. The official track forecast is adjusted a little to the right of the previous forecast beyond 48 hrs to agree more with the TVCA and HCCA consensus models. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 39.3N 41.3W 90 KT 105 MPH 12H 28/1800Z 40.4N 39.2W 85 KT 100 MPH 24H 29/0600Z 42.1N 37.0W 75 KT 85 MPH 36H 29/1800Z 43.5N 35.2W 65 KT 75 MPH 48H 30/0600Z 44.6N 33.1W 55 KT 65 MPH...POST-TROPICAL 60H 30/1800Z 46.0N 31.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 01/0600Z 48.0N 30.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 02/0600Z 52.5N 30.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 03/0600Z 55.7N 28.6W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Roberts

Issued at 0900 UTC SAT SEP 28 2024 000 FONT15 KNHC 280839 PWSAT5 HURRICANE ISAAC WIND SPEED PROBABILITIES NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC SAT SEP 28 2024 AT 0900Z THE CENTER OF HURRICANE ISAAC WAS LOCATED NEAR LATITUDE 39.3 NORTH...LONGITUDE 41.3 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 90 KTS...105 MPH...165 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z SAT 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 SAT 18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED PERIODS TO TO TO TO TO TO TO 18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED 06Z THU FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X 1( 1) 2( 3) 1( 4) X( 4) X( 4) X( 4) $$ FORECASTER ROBERTS

...ISAAC CONTINUES TO STRENGTHEN OVER THE SUBTROPICAL ATLANTIC... ...LARGE AREA OF DANGEROUS HIGH SEAS SPREADING SOUTH OF THE HURRICANE... As of 9:00 AM GMT Sat Sep 28 the center of Isaac was located near 39.3, -41.3 with movement NE at 20 mph. The minimum central pressure was 968 mb with maximum sustained winds of about 105 mph.

Issued at 900 AM GMT Sat Sep 28 2024 000 WTNT35 KNHC 280838 TCPAT5 BULLETIN Hurricane Isaac Advisory Number 10 NWS National Hurricane Center Miami FL AL102024 900 AM GMT Sat Sep 28 2024 ...ISAAC CONTINUES TO STRENGTHEN OVER THE SUBTROPICAL ATLANTIC... ...LARGE AREA OF DANGEROUS HIGH SEAS SPREADING SOUTH OF THE HURRICANE... SUMMARY OF 900 AM GMT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...39.3N 41.3W ABOUT 785 MI...1265 KM W OF THE AZORES MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H PRESENT MOVEMENT...NE OR 55 DEGREES AT 20 MPH...31 KM/H MINIMUM CENTRAL PRESSURE...968 MB...28.59 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 900 AM GMT (0900 UTC), the center of Hurricane Isaac was located near latitude 39.3 North, longitude 41.3 West. Isaac is moving toward the northeast near 20 mph (31 km/h), and this general motion should continue through Monday followed by a turn toward the north-northeast on Tuesday. Maximum sustained winds have increased to near 105 mph (165 km/h) with higher gusts. Little change in strength is expected through mid-day, followed by gradual weakening through the remainder of the forecast period. Isaac is expected to be a post-tropical cyclone on Monday. Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 150 miles (240 km). The estimated minimum central pressure is 968 mb (28.59 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Isaac and a large wind fetch from a deep-layer trough could spread into the Azores through the 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 300 PM GMT. $$ Forecaster Roberts

Issued at 0900 UTC SAT SEP 28 2024 804 WTNT25 KNHC 280838 TCMAT5 HURRICANE ISAAC FORECAST/ADVISORY NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0900 UTC SAT SEP 28 2024 HURRICANE CENTER LOCATED NEAR 39.3N 41.3W AT 28/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 17 KT ESTIMATED MINIMUM CENTRAL PRESSURE 968 MB MAX SUSTAINED WINDS 90 KT WITH GUSTS TO 110 KT. 64 KT....... 0NE 25SE 20SW 0NW. 50 KT....... 20NE 45SE 40SW 25NW. 34 KT....... 50NE 130SE 110SW 50NW. 12 FT SEAS..120NE 360SE 360SW 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 39.3N 41.3W AT 28/0900Z AT 28/0600Z CENTER WAS LOCATED NEAR 38.8N 42.2W FORECAST VALID 28/1800Z 40.4N 39.2W MAX WIND 85 KT...GUSTS 105 KT. 64 KT... 10NE 25SE 20SW 10NW. 50 KT... 30NE 50SE 50SW 40NW. 34 KT... 80NE 130SE 110SW 80NW. FORECAST VALID 29/0600Z 42.1N 37.0W MAX WIND 75 KT...GUSTS 90 KT. 64 KT... 15NE 20SE 20SW 10NW. 50 KT... 50NE 50SE 50SW 50NW. 34 KT...130NE 120SE 110SW 120NW. FORECAST VALID 29/1800Z 43.5N 35.2W MAX WIND 65 KT...GUSTS 80 KT. 64 KT... 0NE 15SE 15SW 0NW. 50 KT... 50NE 50SE 50SW 50NW. 34 KT...170NE 120SE 110SW 140NW. FORECAST VALID 30/0600Z 44.6N 33.1W...POST-TROPICAL MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 40NE 40SE 40SW 50NW. 34 KT...170NE 130SE 110SW 150NW. FORECAST VALID 30/1800Z 46.0N 31.5W...POST-TROP/EXTRATROP MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 40NE 30SE 30SW 40NW. 34 KT...160NE 120SE 100SW 140NW. FORECAST VALID 01/0600Z 48.0N 30.4W...POST-TROP/EXTRATROP MAX WIND 45 KT...GUSTS 55 KT. 34 KT...180NE 90SE 90SW 150NW. 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 02/0600Z 52.5N 30.0W...POST-TROP/EXTRATROP MAX WIND 40 KT...GUSTS 50 KT. 34 KT...180NE 80SE 90SW 120NW. OUTLOOK VALID 03/0600Z 55.7N 28.6W...POST-TROP/EXTRATROP MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 0NE 0SE 150SW 160NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 39.3N 41.3W NEXT ADVISORY AT 28/1500Z $$ FORECASTER ROBERTS

Issued at 500 AM AST Sat Sep 28 2024 000 WTNT41 KNHC 280835 TCDAT1 Tropical Storm Joyce Discussion Number 4 NWS National Hurricane Center Miami FL AL112024 500 AM AST Sat Sep 28 2024 Satellite imagery this morning indicates that Joyce has changed little in organization since the last advisory, with the low-level center located on the southern edge of the convection due to southerly shear. Satellite intensity estimates are clustered near 45 kt and have changed little during the past 6 h, and based on this the initial intensity remains 45 kt. The initial motion is just a little to the right of the previous motion, 305/9 kt. Joyce is on the south side of a narrow subtropical ridge, which is going to weaken and break as a deep-layer trough amplifies over the central Atlantic during the next few days. This evolution should cause Joyce to move slowly to the west-northwest and northwest for a couple of days, followed by an even slower motion toward the north. The track guidance is in generally good agreement through 48 h, but after that time there is some divergence due to a couple of the regional hurricane models forecasting a stronger Joyce to recurve into the aforementioned trough. As with the previous advisory, the track forecast calls for a weaker Joyce to move slowly and not be fully picked up by the trough, and the new forecast track has no significant changes from the previous forecast. Joyce is experiencing moderate southerly shear, and the global models forecast this to continue for the next several days. In addition, the storm will be moving into a gradually drier and subsident environment. Thus, the new intensity forecast is similar to the previous forecast in calling for little change in strength during the next 12 hours, followed by gradual weakening. Simulated satellite imagery from the GFS and ECMWF models suggest that Joyce will lose its convection and become a remnant low by day 3, if not sooner. The remnant low should degenerate into a trough by day 4 or 5, with the remnants subsequently being absorbed by another system approaching from the east. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 19.5N 45.3W 45 KT 50 MPH 12H 28/1800Z 20.0N 46.7W 45 KT 50 MPH 24H 29/0600Z 20.5N 48.2W 40 KT 45 MPH 36H 29/1800Z 21.1N 49.2W 40 KT 45 MPH 48H 30/0600Z 21.7N 49.6W 35 KT 40 MPH 60H 30/1800Z 22.3N 49.7W 30 KT 35 MPH 72H 01/0600Z 22.6N 49.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 02/0600Z 23.0N 50.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 03/0600Z...DISSIPATED $$ Forecaster Beven

...JOYCE MOVING NORTHWESTWARD OVER THE OPEN ATLANTIC WITH NO CHANGE IN STRENGTH... As of 5:00 AM AST Sat Sep 28 the center of Joyce was located near 19.5, -45.3 with movement NW at 10 mph. The minimum central pressure was 1004 mb with maximum sustained winds of about 50 mph.

Issued at 500 AM AST Sat Sep 28 2024 000 WTNT31 KNHC 280834 TCPAT1 BULLETIN Tropical Storm Joyce Advisory Number 4 NWS National Hurricane Center Miami FL AL112024 500 AM AST Sat Sep 28 2024 ...JOYCE MOVING NORTHWESTWARD OVER THE OPEN ATLANTIC WITH NO CHANGE IN STRENGTH... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...19.5N 45.3W ABOUT 1165 MI...1875 KM E OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 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 Tropical Storm Joyce was located near latitude 19.5 North, longitude 45.3 West. Joyce is moving toward the northwest near 10 mph (17 km/h), and a west-northwestward to northwestward motion with a decrease in forward speed is expected through Sunday. A slow turn toward the northwest and north is forecast Sunday night and Monday. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Little change in strength is expected today. Weakening is forecast to begin tonight or on Sunday, and Joyce could degenerate into a remnant low by early Tuesday. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 1004 mb (29.65 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Beven

Issued at 0900 UTC SAT SEP 28 2024 000 FONT11 KNHC 280834 PWSAT1 TROPICAL STORM JOYCE WIND SPEED PROBABILITIES NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112024 0900 UTC SAT SEP 28 2024 AT 0900Z THE CENTER OF TROPICAL STORM JOYCE WAS LOCATED NEAR LATITUDE 19.5 NORTH...LONGITUDE 45.3 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 45 KTS...50 MPH...85 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z SAT 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 SAT 18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED PERIODS TO TO TO TO TO TO TO 18Z SAT 06Z SUN 18Z SUN 06Z MON 06Z TUE 06Z WED 06Z THU FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT $$ FORECASTER BEVEN

Issued at 0900 UTC SAT SEP 28 2024 000 WTNT21 KNHC 280833 TCMAT1 TROPICAL STORM JOYCE FORECAST/ADVISORY NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112024 0900 UTC SAT SEP 28 2024 TROPICAL STORM CENTER LOCATED NEAR 19.5N 45.3W AT 28/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 305 DEGREES AT 9 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT. 34 KT....... 40NE 20SE 20SW 90NW. 12 FT SEAS..120NE 0SE 0SW 90NW. 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 19.5N 45.3W AT 28/0900Z AT 28/0600Z CENTER WAS LOCATED NEAR 19.3N 44.9W FORECAST VALID 28/1800Z 20.0N 46.7W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 50NE 20SE 20SW 70NW. FORECAST VALID 29/0600Z 20.5N 48.2W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 50NE 20SE 0SW 40NW. FORECAST VALID 29/1800Z 21.1N 49.2W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 50NE 20SE 0SW 30NW. FORECAST VALID 30/0600Z 21.7N 49.6W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 30NE 20SE 0SW 20NW. FORECAST VALID 30/1800Z 22.3N 49.7W MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 01/0600Z 22.6N 49.7W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 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 02/0600Z 23.0N 50.5W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. OUTLOOK VALID 03/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.5N 45.3W NEXT ADVISORY AT 28/1500Z $$ FORECASTER BEVEN

5-Day Uncertainty Track last updated Sat, 28 Sep 2024 08:36:40 GMT


Wind Speed Probabilities last updated Sat, 28 Sep 2024 09:29:23 GMT

000
ABNT20 KNHC 280526
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sat Sep 28 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Isaac, located over the central Subtropical Atlantic Ocean, and on
Tropical Storm Joyce, located over the central Tropical Atlantic
Ocean. The Weather Prediction Center is issuing advisories on
Post-Tropical Cyclone Helene, located inland over the Ohio River
Valley.

Eastern and Central Tropical Atlantic:
A broad and elongated area of low pressure, associated with a
tropical wave, is producing limited shower activity near and to the
west of the Cabo Verde Islands. Environmental conditions appear
conducive for gradual development of this system, and a tropical
depression could form next week while moving toward the west and
then northwest at about 10 mph across the eastern and central
tropical Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...50 percent.

Western Caribbean Sea and Gulf of Mexico:
An area of low pressure could form over the western Caribbean Sea by
the early part of next week. Environmental conditions are expected
to be conducive for additional development thereafter while the
system moves generally northwestward, and a tropical depression
could form by the middle of next week as the system enters the Gulf
of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.

&&
Public Advisories on Tropical Storm Joyce are issued under WMO
header WTNT31 KNHC and under AWIPS header MIATCPAT1.
Forecast/Advisories on Tropical Storm Joyce are issued under WMO
header WTNT21 KNHC and under AWIPS header MIATCMAT1.

$$
Forecaster Beven

Issued at 300 AM GMT Sat Sep 28 2024 000 WTNT45 KNHC 280315 TCDAT5 Hurricane Isaac Discussion Number 9 NWS National Hurricane Center Miami FL AL102024 300 AM GMT Sat Sep 28 2024 Isaac has maintained a well-defined eye on both visible and infrared imagery for the past 12 hours or so. The latest subjective Dvorak classifications are a consensus T-4.5/77 kt from TAFB and SAB. The latest objective intensity estimates from UW-CIMSS range from 72 to 92 kt. The initial intensity is adjusted upward to 80 kt based on a blend of the subjective and objective estimates. The hurricane is moving east-northeastward, or 075/14 kt. Isaac is currently moving in the zonal flow with the mid-latitude westerlies. A powerful deep-layer trough over Atlantic Canada will approach Isaac by Saturday night as a narrow mid-level ridge builds to the north of Isaac. These steering features will cause Isaac to bend a bit more toward the northeast while slowing down slightly. On Monday, after Isaac becomes post-tropical, a turn more toward the north-northeast is expected, as the deep-layer trough moves eastward and the ridge moves northward. No significant changes have been made to the official forecast track forecast through the first 60-72 h. After that time, a sizable westward adjustment is made to the official forecast track, but the new NHC forecast track is well east of the latest consensus models beyond 72 h. It is possible Isaac could strengthen a little more tonight, although the hurricane is likely near its peak intensity. The cyclone is crossing the 26 degree C isotherm now, but is forecast to remain over 24-26 degree C sea-surface temperatures for another 36 h or so. The cold upper-level temperatures that Isaac is forecast to traverse should help maintain enough instability such that only slow weakening is forecast through 36 h, and Isaac is expected to maintain hurricane strength through that time. Also, although moderate southwesterly shear is forecast to increase slightly, the shear direction is the same as the direction of Isaac's motion, so this should not be too unfavorable. Beyond 48 h, sea-surface temperatures decrease significantly and wind shear is forecast to become very strong. This should cause the cyclone to lose its deep convection by Monday and then become extratropical. Little to no change was made to the previous official intensity forecast, while lies near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 38.2N 43.4W 80 KT 90 MPH 12H 28/1200Z 39.5N 40.9W 80 KT 90 MPH 24H 29/0000Z 41.0N 38.6W 75 KT 85 MPH 36H 29/1200Z 42.5N 37.0W 70 KT 80 MPH 48H 30/0000Z 43.8N 35.4W 60 KT 70 MPH 60H 30/1200Z 45.0N 33.7W 55 KT 65 MPH...POST-TROPICAL 72H 01/0000Z 46.9N 32.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 02/0000Z 50.9N 31.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 03/0000Z 53.8N 29.5W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Hagen

The NHC has issued its final advisory on this system. Public Advisories from the Weather Prediction Center will provide updates as long as the system remains a flood threat. Issued at 1000 PM CDT Fri Sep 27 2024

5-Day Uncertainty Track last updated Sat, 28 Sep 2024 02:42:29 GMT

5-Day Uncertainty Track last updated Sat, 28 Sep 2024 02:42:29 GMT


Wind Speed Probabilities last updated Sat, 28 Sep 2024 03:29:00 GMT

5-Day Uncertainty Track last updated Sat, 28 Sep 2024 02:40:56 GMT


Wind Speed Probabilities last updated Sat, 28 Sep 2024 03:23:03 GMT

Issued at 0300 UTC SAT SEP 28 2024 000 FONT15 KNHC 280238 PWSAT5 HURRICANE ISAAC WIND SPEED PROBABILITIES NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024 0300 UTC SAT SEP 28 2024 AT 0300Z THE CENTER OF HURRICANE ISAAC WAS LOCATED NEAR LATITUDE 38.2 NORTH...LONGITUDE 43.4 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 80 KTS...90 MPH...150 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 SAT 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 SAT 12Z SAT 00Z SUN 12Z SUN 00Z MON 00Z TUE 00Z WED PERIODS TO TO TO TO TO TO TO 12Z SAT 00Z SUN 12Z SUN 00Z MON 00Z TUE 00Z WED 00Z THU FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X X( X) 1( 1) 2( 3) X( 3) X( 3) X( 3) $$ FORECASTER HAGEN