946
WTNT44 KNHC 082100
TCDAT4
HURRICANE ISAIAS DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092026
400 PM CDT THU OCT 08 2026
THE EYE OF ISAIAS HAS BECOME APPARENT ON VISIBLE AND INFRARED
SATELLITE IMAGERY. INTERESTINGLY, THIS IS THE FIRST EYE NOTED ON
SATELLITE PICTURES IN THE ATLANTIC BASIN DURING THE 2026 HURRICANE
SEASON. THE CLOUD TOPS HAVE MOSTLY WARMED IN THE SYSTEM, BUT THE
LATEST SUBJECTIVE DVORAK CLASSIFICATION VALUE FROM TAFB HAS
INCREASED TO T4.5 OR 77 KT. NOAA HURRICANE HUNTER AIRCRAFT
OBSERVATIONS DO NOT INDICATE A DROP IN CENTRAL PRESSURE SO FAR AND
THE PEAK 700-MB FLIGHT-LEVEL WINDS HAVE NOT INCREASED. HOWEVER,
TAIL DOPPLER RADAR WIND VELOCITIES FROM THE AIRCRAFT MEASURED JUST
ABOVE THE SURFACE SUPPORT INCREASING THE INTENSITY TO 85 KT FOR
THIS ADVISORY.
SATELLITE AND AIRCRAFT CENTER FIXES INDICATE THAT THE HURRICANE
APPEARS TO HAVE MADE ITS EXPECTED TURN TOWARD THE NORTHEAST AND THE
INITIAL MOTION IS NOW 050/10 KT. ISAIAS IS EXPECTED TO TURN
NORTHWARD TOMORROW AND MOVE BETWEEN A MID-LEVEL RIDGE EXTENDING
WESTWARD FROM THE BAHAMAS TO THE FLORIDA PENINSULA AND A TROUGH
NEAR THE NORTHWEST GULF COAST. ON THE FORECAST TRACK, THE CENTER
WILL MOVE INLAND ALONG THE NORTHERN GULF COAST WITHIN THE NEXT 36
HOURS, AND THEN PASS OVER PORTIONS OF THE SOUTHEASTERN U.S. DURING
THE NEXT FEW DAYS. THE OFFICIAL FORECAST IS NUDGED SLIGHTLY
EASTWARD AND FOLLOWS THE LATEST CORRECTED CONSENSUS MODEL GUIDANCE.
THE INTENSITY FORECAST REMAINS SOMEWHAT PROBLEMATIC. THE HURRICANE
WILL BE PASSING OVER GULF WATERS OF HIGH OCEANIC HEAT CONTENT
DURING THE NEXT DAY OR SO. IN FACT, THE PROJECTED TRACK OF ISAIS
SHOWS IT PASSING NEAR A WARM EDDY OVERNIGHT. HOWEVER, THE VERTICAL
WIND SHEAR, WHICH IS ALREADY SIGNIFICANT, IS EXPECTED TO INCREASE
SUBSTANTIALLY DURING THE NEXT 36 HOURS. THE CURRENT THINKING IS THAT
THE SHEAR WILL NOT OFFSET THE CONDUCIVE OCEANIC CONDITIONS UNTIL
12-24 HOURS, SO FURTHER STRENGTHENING IS ANTICIPATED OVERNIGHT. THE
OFFICIAL INTENSITY FORECAST IS AT THE HIGH END OF THE MODEL
GUIDANCE, BUT IN CONSIDERATION OF THE EXPECTED STRONGER WIND SHEAR
IN 24-36 HOURS, SOME DECREASE IN INTENSITY IS INDICATED AS ISAIAS
APPROACHES THE COAST. REGARDLESS, ISAIAS IS EXPECTED TO REMAIN A
DANGEROUS HURRICANE THROUGH LANDFALL, AND STRONG GUSTY WINDS ARE
EXPECTED WELL INLAND AFTER THE CENTER CROSSES THE COAST.
KEY MESSAGES:
1. A LIFE-THREATENING STORM SURGE IS EXPECTED FROM THE MOUTH OF THE
MISSISSIPPI RIVER TO SUWANNEE, FLORIDA. RESIDENTS IN THE WARNING
AREA SHOULD FOLLOW ADVICE GIVEN BY LOCAL OFFICIALS AND EVACUATE
IMMEDIATELY IF TOLD TO DO SO.
2. DAMAGING HURRICANE FORCE-WINDS ARE EXPECTED OVER PORTIONS OF THE
FLORIDA PANHANDLE, SOUTHERN ALABAMA, AND SOUTHERN MISSISSIPPI WHERE
A HURRICANE WARNING IS IN EFFECT. RESIDENTS IN THESE AREAS SHOULD
PREPARE FOR THE POSSIBILITY OF LONG-DURATION POWER OUTAGES.
3. DAMAGING WIND GUSTS ARE POSSIBLE OVER MUCH OF CENTRAL AND
NORTHERN ALABAMA, EXTREME EASTERN MISSISSIPPI, AND PORTIONS OF
WESTERN AND NORTHERN GEORGIA, ESPECIALLY IN AREAS OF HIGHER TERRAIN.
ADDITIONAL TROPICAL STORM AND HIGH WIND WATCHES AND WARNINGS MAY BE
REQUIRED FOR PORTIONS OF THAT AREA LATER TONIGHT. RESIDENTS SHOULD
SECURE LOOSE OUTDOOR ITEMS, AVOID DRIVING HIGH-PROFILE VEHICLES, AND
PREPARE FOR POWER OUTAGES.
4. ISAIAS WILL BRING AREAS OF HEAVY RAINFALL TO THE CENTRAL U.S.
GULF COAST AND MUCH OF THE SOUTHEAST FRIDAY INTO THE WEEKEND.
CONSIDERABLE FLASH AND URBAN FLOODING, ALONG WITH SIGNIFICANT RIVER
FLOODING, WILL BE POSSIBLE.
FORECAST POSITIONS AND MAX WINDS
INIT 08/2100Z 24.4N 89.3W 85 KT 100 MPH
12H 09/0600Z 25.7N 88.4W 95 KT 110 MPH
24H 09/1800Z 28.2N 87.4W 85 KT 100 MPH
36H 10/0600Z 31.0N 87.2W 65 KT 75 MPH...INLAND
48H 10/1800Z 33.2N 87.8W 30 KT 35 MPH...INLAND
60H 11/0600Z 35.0N 87.8W 25 KT 30 MPH...POST-TROP/INLAND
72H 11/1800Z 37.0N 85.0W 20 KT 25 MPH...POST-TROP/INLAND
96H 12/1800Z...DISSIPATED
FORECASTER PASCH
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