530PM EDT: As I'd suspected for a few days now, Tropical Storm Debby will miss Louisiana altogether and make landfall in the Florida Panhandle near Tallahassee over the next few days. The tropical storm warnings have been pruned back to reflect this change. The National Hurricane Center is a great organization that does amazing things (and is usually right on the money), but they busted this forecast hard. I'll have a diary later tonight detailing why the NHC got their forecast so wrong. I've updated the information below to reflect the large change in the forecast. To be clear, I will always relay what the official NHC forecast says, regardless of what I think about it.
An asymmetrical Tropical Storm Debby on radar.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT...
A TROPICAL STORM WARNING IS IN EFFECT FOR...
* THE MISSISSIPPI-ALABAMA BORDER EASTWARD TO THE SUWANNEE RIVER
A TROPICAL STORM WATCH IS IN EFFECT FOR...
* SOUTH OF THE SUWANNEE RIVER TO ENGLEWOOD FLORIDA
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN 12 TO 24 HOURS.
The models for Tropical Storm Debby have been all over the place since they started running them a few days ago. For the most part, the models have been pretty evenly split between a westward solution, bringing it into Texas, and an eastward solution that would bring Debby into Florida. On Friday, I predicted that it would hit Florida just because that's where a majority of the models were pointed. Yesterday, the NHC started issuing advisories on newly formed Tropical Storm Debby and predicted that it would hit Texas because that's where a majority of yesterday's models said it would hit. Late last night, the new model runs came in and everything changed. All of the models suddenly decided to make a major shift to the east. The new forecast track from the NHC has Debby meander in the northeastern Gulf for the next day or two, before moving northwest into the Louisiana coast as a minimal hurricane.
Refer to the 530PM update at the top of the diary.
Not to doubt the NHC, but I think there's still a large amount of uncertainty here. The models are still pretty split on this solution. Anyone from Lake Charles, LA to Tampa, Fl still needs to keep an eye on this storm.
What To Expect
Heavy Rain/Flooding: Regardless of Debby's path, a large portion of the Northern Gulf Coast will be impacted by heavy rain, strong winds, and possibly a tornado or two. I think the big story with Debby will be its rains. It is still a very asymmetrical storm, with virtually nothing to the west of the center, and all the wind and precip off to the east of the center over Florida.
As the system approaches the coast over the next few days, this shield of wind and rain will slowly make its way west towards Pensacola, Mobile, Biloxi, and New Orleans. As seen by the HPC's 5 day total accumulated rainfall forecast, extremely heavy rain is expected immediately along the coast, with 10+ inches possible in some areas. The legend on the left is in inches.
Wind: A tropical storm warning is in effect for a large portion of the northern Gulf Coast, meaning that tropical storm force winds of 45-74 MPH (with higher gusts) are likely to occur within the next 36 hours.
The NHC's forecast has Debby becoming a minimal hurricane just before landfall in Louisiana on Wednesday, meaning that winds will be an increasing threat over the next few days. The NHC's 500PM EDT forecast has Debby maintaining Tropical Storm strength until it makes landfall on the Florida Panhandle. Make sure you secure all loose objects outside and do what you can to minimize property and tree damage in your area. Be prepared for power outages and blocked roadways.
Tornadoes: As with any landfalling tropical system, tornadoes are a threat. The tornadoes usually aren't much stronger than EF-0 or EF-1, but a tornado is a tornado nonetheless. Keep a close eye on the weather and be prepared to take immediate action if a tornado warning is issued. Even a weak tornado can be deadly.
Evacuations: If you live in an area that receives an evacuation order, don't willfully ignore it. If possible, evacuate the area when told. If you can't evacuate, see if you can go with a close friend or relative. If you stay (either willfully or due to circumstance), be prepared to face those issues that arise when a storm hits.
I'll post another update on this storm late tonight, with subsequent updates throughout the weekend and into the week as this storm approaches the coast. Stay tuned to the National Hurricane Center, National Weather Service, and other official media outlets for the latest information.
National Weather Service Tampa FL
National Weather Service Tallahassee FL
National Weather Service Mobile AL
National Weather Service New Orleans LA
National Weather Service Lake Charles LA
National Weather Service Houston TX
National Weather Service Brownsville TX