Tropical Storm Isaias Warnings Expanded Georgia to Maine Flash Flood Watch Tuesday
it is very rare to see tropical storm warnings up for the entire US Eastern Seaboard but at one point earlier today we had warnings up from Florida to Maine. Now we have Georgia to Maine as Isaias continues on its northward track up the coast. Satellite pictures and recon reports show that Isaias is moving north northeast now and it is getting better organized so there might be one last climb to minimal hurricane strength before landfall near the South Carolina North Carolina border later tonight.
Some showery rain bands with heavy downpours that developed inland are well ahead of Isaias which can see on the local radars below from Morehead City & Wilmington NC. The center should be coming within range of these radars shortly.
LOCAL RADAR MOREHEAD CITY NC
5PM LOCATION…32.0N 79.4W
ABOUT 60 MI…100 KM SSE OF CHARLESTON SOUTH CAROLINA
ABOUT 120 MI…195 KM SSW OF MYRTLE BEACH SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS…70 MPH…110 KM/H
PRESENT MOVEMENT…NNE OR 15 DEGREES AT 16 MPH…26 KM/H
MINIMUM CENTRAL PRESSURE…993 MB…29.33 INCHES
There are no major changes in the forecast outlook however it does seem that Isaias will be able to maintain strength as a tropical storm on its trip up the coast. Heaviest rains will be west of the track and strongest winds to the east but we have expanded the wind field westward as Isaias will be influenced by a strong upper air jet stream and this will create some rather strong wind gusts to 60 mph or higher especially along the coast.
The faster it gets in, the faster it gets out. The first frame here is at 2am and the last at 8am Wednesday on the GFS. It is the faster of the models. For much of Eastern Pennslyvania to Southern New England the heaviest rains and the strongest winds will last about 6 hours though we will some areas getting showery rains overnight into Tuesday morning. Rainfall amounts west of the low track could easily exceed 4 inches.
The core heavy rain will arrive in South Jersey and Southern Pennsylvania around daybreak and reach NYC by mid to late morning and in the Hudson Valley shortly afterwards. It ends late afternoon across South Jersey and Southern Pennsylvania and the back edge reaches NYC in an east west line around 8pm or so and a few hours later in points north.
Notice that core of heavy rain in Eastern Pennsylvania is likely to clobber some areas with 6 inches of rain in spots. To the east of the storm track the rainfall is less but the winds are stronger. You can see tht the western edge of the strong gusts has been pulled back westward into Southeastern Pennsylvania and Western New Jersey. Winds will gust 50 to 60 mph or even higher along shore locations and inland some gusts will reach 40 to 50 mph.
One last thing is the threat for severe weather. The Storm Prediction Center has a slight risk of severe weather forecast and a 5% chance for tornadoes. This will set up east of the storm track and usually occurs where you have the strongest southeast winds.
Once this is all done weather conditions should improve quickly overnight and we should have some sunshine on Wednesday wiith highs highs in the 80s and slightly lower humidity (hopefully).
MANY THANKS TO TROPICAL TIDBITS FOR THE USE OF MAPS
Please note that with regards to any severe weather, tropical storms, or hurricanes, should a storm be threatening, please consult your local National Weather Service office or your local government officials about what action you should be taking to protect life and property.