1. National Weather Service Weather Forecast Office Mobile - Pensacola
Special Update Briefing
Hurricane Isaac
Self introduction and introduction of topic.
Jeff Garmon
Warning Coordination Meteorologist
6 PM CDT Tuesday 28 August 2012

2. This outlook is intended for interests across interior southeast Mississippi, south Alabama, the western Florida Panhandle, and the adjacent Gulf coastal waters of Alabama and northwest Florida

3. Satellite Image Hurricane Isaac

4. Impacts extend well east and outside the cone!
The cone represents, based on our average track error, where the CENTER of the hurricane will be 2/3rds of the time)
Tropical storm force winds extend eastward for 185 miles.

5. Warnings and Watches in Effect
Hurricane Warning for Mobile and Baldwin was replaced by Tropical Storm Warning at 10 AM today…THAT DOES NOT MEAN LESS STORM SURGE IS EXPECTED.

6. Short Term Concerns… Strong squall-lines
Bands of strong squalls on the east side of Hurricane Isaac will continue moving northwest across the coast spreading across interior SE Mississippi and SW Alabama through the overnight period.
Periodic gusts to near 60 mph will be possible with these passing squalls. This will bring down trees and power lines.
As these squalls move through, strong southeasterly winds associated with them will help bring water levels up along the coastline… increasing coastal flood threat.
Strong squall-lines
NW 8 mph

7. Coastal Flood Considerations
Storm surge possible of 5 to 8 feet above ground level coastal Mobile and Baldwin counties, and 3 to 5 feet above ground level along the western Florida panhandle late tonight and Wednesday morning.

8. Tropical Storm Force Winds Extend North and Eastward from the Center for 185 Miles
Periods of tropical storm force winds from 40 to 50 mph gusting to 60 mph will continue for several more hours across extreme southwest Alabama, the western Florida panhandle and southeast Mississippi.
NW 8 mph

9. Wind Impacts: Forecast Wind Envelope Tue PM-Wed PM
Main areas to expect minor structural damage, downed trees and power outages are:
Mobile, Baldwin, Stone, George, Greene, and Perry counties.
Southern exposed areas of Escambia, Santa Rosa and Okaloosa counties will see periodic gusts to tropical storm force with passing rain squalls.
Timing of TS force winds:
Now through Wednesday Mobile-Baldwin and coastal areas of the western Florida panhandle.
This evening through Wednesday for interior SE Mississippi counties.
Winds <39 mph
Winds mph
>73 mph
58-73 mph

10. Tornado Risk
We are looking at a risk for isolated tornadoes today through Wednesday.
We will need to watch for stronger storms in bands on the east side of Isaac.
As these bands move across gusts to 60 mph may be possible… especially along the coastal counties.

11. Heavy Rain Threat Through Wednesday
Greatest risk for flash flooding in our area is over southeast Mississippi and extreme southwest Alabama
Greatest Risk for Flash Flooding

12. Main Points to Consider…
Still looking at a category 1 hurricane landfall in SE Louisiana tonight.
Periods of tropical storm force winds will continue to affect the coastal counties of Alabama and the western Florida panhandle through Wednesday. These winds will spread inland in squalls across interior southeast Mississippi this evening and last through Wednesday.
Tropical storm winds will likely abate Wednesday evening.
Maximum storm surge along the coast will be late tonight and Wednesday morning as we approach high tide…with an additional 3 to 5 feet of water rise possible. We are still forecasting the potential of 5 to 8 feet of storm surge around the Alabama coast and 3 to 5 feet of storm surge along the western Florida panhandle.
There is a chance that we could see 8 to 12 inches of rain over SE Mississippi and extreme SW Alabama. This would also result in an increased risk of freshwater flooding by Wednesday. A flash flood watch has been issued for the areas at higher risk for flooding in SE Mississippi and SW Alabama.
Isolated tornado risk will continue through Wednesday…and will gradually spread across the inland counties overnight into Wednesday.

13. EMBrief Page Available weather.gov/mob/?n=embrief

14. To Contact NWS Mobile Phone… Public: 1-800-284-9059
Forecast Desk – Briefings (unlisted):
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