Issac Update August 25, 11pm

Good evening all,

Sleep deprivation has not won the battle...yet!
Issac has emerged off the northern Cuban coast and is still having problems with the terrain from the mountains over eastern Cuba. From satellite interrogation we find there is a hole in the convection along the land side of the storm. This is likely due to the mountain shadow produced  by down sloping winds moving with the storm. 

The mountain shadow is very clearly shown in the latest ASCAT satellite pass. The wind barbs are red as each barb is worth 10 knots, and the color coding may help. The green would be 30 to 40 knots, dark blue 20 to 30 knots, and ligth blue 10 to 20 knots. (Remember I'm a little color blind so I hope these colors are correct)

The forecast track once again is clustered around the global and mesoscale model consensus that has been in very good agreement even with the ECMWF for the past 6 or 7 runs. Now that the storm is on the north side of Cuba there is absolutely no reason to go against it. 

The time for preparations has passed for the Keys and the storm may pass just before high tide which will put the storm tide as high as 2 to 4 feet. High tide in Key West is 732 pm, and at Pigeon Key in the middle of 7 Mile Bridge is at 637 pm. The storm should be crossing over Key West around 5 pm and may intensify into a minimal category one hurricane as it passes the Lower Keys.

Key West Tides

Marathon, Pigeon Key Tides

From the National Hurricane Center:

A HURRICANE WARNING IS IN EFFECT FOR...* THE FLORIDA KEYS INCLUDING THE DRY TORTUGAS* THE WEST COAST OF FLORIDA FROM BONITA BEACH SOUTHWARD TO OCEAN REEF* FLORIDA BAY A HURRICANE WATCH IS IN EFFECT FOR...* THE FLORIDA EAST COAST FROM GOLDEN BEACH SOUTHWARD TO OCEAN REEF* ANDROS ISLAND IN THE BAHAMAS

A TROPICAL STORM WARNING IS IN EFFECT FOR...* THE BAHAMAS* TURKS AND CAICOS ISLANDS* THE FLORIDA EAST COAST FROM SEBASTIAN INLET SOUTHWARD TO OCEAN REEF* LAKE OKEECHOBEE* THE FLORIDA WEST COAST FROM NORTH OF BONITA BEACH TO TARPON SPRINGS...INCLUDING TAMPA BAY A TROPICAL STORM WATCH IS IN EFFECT FOR...* THE FLORIDA EAST COAST NORTH OF SEBASTIAN INLET TO FLAGLER BEACH* THE FLORIDA WEST COAST AND THE FLORIDA PANHANDLE NORTH OF TARPON SPRINGS TO INDIAN PASS

The thinking is that the track has settled down and should be far enough west to make for off shore winds through Tampa Bay. This would keep the risk of storm tides lower than if Issac were to track nearer to the coast. The big question in the forecast is intensity and location at landfall. The storm will head over some warm waters for a rather long period of time even before it reaches the Keys, and then over the southeastern Gulf of Mexico. For this reason I think the intensity forecast may be pretty good and have no reason to disagree. 

Keep checking your local National Weather Service Office for local hurricane statements which should include shelter and evacuation information for your local area.