Monday, August 27, 2012 5:42 am

by Rob Lightbown of Crown Weather

Tropical Storm Isaac:
Isaac has strengthened a little over the past 24 hours with the most recent central pressure of 990 millibars. As of this morning, Isaac is tracking generally west northwestward at a forward speed of 13 to 14 mph. Like yesterday, the main player in the forecast track of Isaac is a gap in the ridge of high pressure. This gap is currently located over the northern Gulf of Mexico and the latest guidance continue to have some differences in the overall forecast track of Isaac as it approaches the northern Gulf coast on Tuesday afternoon.

The latest GFS model guidance forecasts a landfall on Wednesday morning just west of Morgan City. The European model guidance forecasts a landfall just west of Gulfport, Mississippi during Wednesday morning. The Canadian model forecasts a landfall right on the Louisiana-Mississippi state line right around midday Wednesday. Finally, the consensus track guidance pulls Isaac inland right over New Orleans late Tuesday night.

So, based on the evidence this morning I am shifting the forecast track of Isaac westward and I do concur with the consensus guidance with a landfall close to New Orleans just after midnight Tuesday night. Environmental conditions are expected to be favorable from today through Tuesday and strengthening is likely. I do still think that Isaac will be a Category 2 hurricane with right around 100 mph winds when it makes landfall on Tuesday night. Please be aware that the forecast track is not etched in stone and that this forecast track may need to be adjusted.

Impacts From Isaac:
Storm Surge Impact: The following storm surges can be expected:

Southeast Louisiana, the Mississippi coastline & the Alabama coastline: 6 to 12 Feet.
South-Central & Southwestern Louisiana: 3 to 6 Feet.
The Florida Panhandle: 3 to 6 Feet.

Wind Impact: Tropical Storm force winds will overspread the northern Gulf coast from Louisiana to the Florida Panhandle by this evening with tropical storm conditions expected throughout the night tonight. On Tuesday, hurricane force winds are expected to overspread areas from southeastern Louisiana to the Mississippi and Alabama coastlines during Tuesday afternoon with hurricane conditions continuing across this area throughout Tuesday night and into Wednesday morning.

Rainfall Impact: Additional rainfall amounts of 1 to 3 inches are expected today across central and south Florida. Total rainfall amounts of 7 to 15 inches with isolated amounts of 20 inches is expected from Tuesday through Wednesday across southeastern Louisiana, southern Mississippi, southern Alabama and the western Florida Panhandle.

Residents and vacationers from the Florida Panhandle westward to the Louisiana coastline as far west as Vermilion Bay need to closely monitor the progress of Isaac as the forecast track may change between now and the time of landfall, which is expected either late Tuesday night or during Wednesday morning.

I am constantly monitoring the progress of Isaac and will continue to have frequent updates on the storm.