Tropical Storm Isaias Saturday Evening Update
Currently
Tropical Storm Isaias has had an up-and-down day starting as a category one hurricane before suffering a blow by wind shear and dry air earlier today that left the low-level circulation separated from the main convection to the northeast. Air Force Reserve reconnaissance found winds had weakened to tropical storm strength and was downgraded to a tropical storm by the 5:00PM advisory. But Isaias still has a little fight in him as he approaches the eastern coast of Florida. Convection has really picked up on the northeastern quadrant of the storm but the shear still hasn’t diminished much. Current satellite imagery shows the outflow of top of the convection expanding outward except on the southwestern side of the storm where you can see a straight line in the convection from north of Miami southeastward towards Cuba. This is indicating the outflow isn’t expanding on that side of the storm due to the persistent southwesterly shear. Dry air to the west of the storm will continue to be an issue moving forward as well.
Short-term
As of the 8:00 PM advisory, Isaias was still a tropical storm with maximum winds at 70 mph, central minimum pressure of 993 mb. The storm continues to move northwestward at 9 mph and is forecast to slow even further as the trough over the central US continues to push eastward which will turn the storm northward then north-northeastward and increase in speed on Monday-Tuesday. Prior to that the storm is forecast to ride along the east coast of Florida or even make a brief landfall on Sunday as it rounds the western edge of the sub-tropical ridge. There is a possibility that it could restrengthen into a hurricane prior to landfall but conditions do not remain favorable for strengthening much beyond that. Hurricane watches/warnings and Tropical Storm watches/warnings still remain in effect for most of the eastern coast of Florida.
Impacts on ENC
Once Isaias is picked up by the trough it will accelerate to the north-northeast which could briefly emerge back over the water as it moves along the coast and making landfall along the South Carolina or North Carolina coast. It doesn’t appear at this time that the storm will be able to restrengthen into a hurricane during this time-frame but will remain a strong tropical storm as it moves through these areas. Strong, damaging winds, heavy rain, and dangerous storm surge (as well as some isolated tornadoes) will still impact the area Monday night through early Tuesday. This storm will be picking up pretty good speed at this point and tropical storm conditions could be pushing out of the area by Tuesday night. I urge caution as the models are not in agreement on the exact timing yet so some adjustments to the forecast may be needed as time goes on. Keep up-to-date with the NHC and NWS for watches and warnings that will be issued at some point over the next two days.
With the storm approaching the area on Monday, that leaves one day to prepare for a tropical storm over Eastern North Carolina. Take the opportunity while the weather is quiet (partly cloudy with highs in the low-to-mid 90s on Sunday) to finish preparations.
More updates coming tomorrow on encweather.com but I plan on posting some comments/updates on Facebook tomorrow throughout the day.
