Isaias, advisory 9

000
WTNT34 KNHC 082057
TCPAT4
 
BULLETIN
Hurricane Isaias Advisory Number   9
NWS National Hurricane Center Miami FL       AL092026
400 PM CDT Thu Oct 08 2026
 
...HURRICANE HUNTERS FIND THAT ISAIAS NOW HAS 100 MPH WINDS...
...PREPARATIONS TO PROTECT LIFE AND PROPERTY FROM STORM SURGE AND
DAMAGING WINDS IN THE WARNING AREA SHOULD BE RUSHED TO COMPLETION
TODAY...
 
 
SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...24.4N 89.3W
ABOUT 215 MI...345 KM N OF PROGRESO MEXICO
ABOUT 325 MI...525 KM S OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...NE OR 50 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
None.
 
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
 
A Storm Surge Warning is in effect for...
* Mouth of the Mississippi River to the Suwannee River
 
A Hurricane Warning is in effect for...
* Ocean Springs, MS to the Bay/Gulf County Line, FL
 
A Tropical Storm Warning is in effect for...
* Jefferson/Plaquemines Parish Line, LA to west of Ocean Springs, MS
* East of Bay/Gulf County Line to Aucilla River, FL
 
A Storm Surge Watch is in effect for...
* Suwannee River to Yankeetown
 
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 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.
 
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 400 PM CDT (2100 UTC), the eye of Hurricane Isaias was located
near latitude 24.4 North, longitude 89.3 West. Isaias is moving
toward the northeast near 12 mph (19 km/h).  A turn toward the
north is expected on Friday.  On the forecast track, Isaias is
expected to pass to the north of the Yucatan Peninsula through
this evening and make landfall along the U.S. northern Gulf Coast
within the warning area late Friday or early Saturday.
 
Maximum sustained winds have increased to near 100 mph (155 km/h) 
with higher gusts.  Additional strengthening is expected through 
early Friday, and Isaias should remain a dangerous hurricane as it 
approaches the northern Gulf Coast Friday night.
 
Hurricane-force winds extend outward up to 15 miles (30 km) from the
center and tropical-storm-force winds extend outward up to 125 miles
(205 km).
 
The estimated minimum central pressure is 975 mb (28.80 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
Key messages for Isaias can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC.
 
STORM SURGE: The combination of a dangerous 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...
 
Ocean Springs, MS to Indian Pass, FL...5-7 ft
Mobile Bay...5-7 ft
Indian Pass, FL to Steinhatchee River, FL...4-6 ft
Mouth of the Mississippi River, LA to Ocean Springs, MS...3-5 ft
Steinhatchee River, FL to Suwannee River, FL...3-5 ft
Suwannee River, FL to Yankeetown, FL...2-4 ft
 
The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
dangerous waves. Surge-related flooding depends on the relative
timing of the surge and the tidal cycle, and can vary greatly over
short distances. For information specific to your area, please see
products issued by your local National Weather Service forecast
office.
 
For a complete depiction of areas at risk of storm surge inundation,
please see the National Weather Service Peak Storm Surge Graphic,
available at hurricanes.gov/graphics_at4.shtml?peakSurge.
 
WIND: Hurricane conditions are expected within the Hurricane Warning 
area Friday night into early Saturday, with tropical storm 
conditions beginning on Friday. Tropical storm conditions are 
expected in the warning areas on Friday and Friday night.
 
Gusty winds are possible in portions of the Yucatan Peninsula for
the next several hours.
 
RAINFALL: From Friday through the weekend, Isaias is expected to 
produce rainfall amounts of 4 to 8 inches across southern Alabama, 
the Florida Panhandle and Big Bend, and southwest Georgia. Localized 
totals up to 15 inches are possible, particularly within banding 
across the Florida Panhandle and Big Bend. Across the coastal 
Carolinas, rainfall of 3 to 5 inches, with localized totals up to 8 
inches are possible. Rainfall amounts of 1 to 3 inches, with 
localized amounts up to 5 inches, are possible across much of the 
remainder of the Southeast. Flash and urban flooding is likely 
across the region, with considerable impacts possible across much of 
southern Alabama and the Florida Panhandle into southwestern 
Georgia. River flooding is also expected, some of which could be 
significant.
 
For a complete depiction of forecast rainfall associated with 
Isaias, 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: An isolated risk for tornadoes will begin Friday night in
coastal areas of Alabama, the Florida Panhandle and far southwestern
Georgia. The tornado threat will continue Saturday for eastern
Alabama, Georgia, and the Florida Panhandle.
 
SURF: Swells will affect the western and northern portions of the
Yucatan Peninsula today and spread northward toward the Gulf Coast
on Friday. These swells are likely to cause life-threatening surf
and rip current conditions. Please consult products from your local
weather office.
 
A depiction of rip current risk for the United States can be found
at: hurricanes.gov/graphics_at4.shtml?ripCurrents
 
 
NEXT ADVISORY
-------------
Next intermediate advisory at 700 PM CDT.
Next complete advisory at 1000 PM CDT.
 
$$
Forecaster Pasch
 

000
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