Monday, November 9, 2009

It Comes down to this: IDA Vs. Strong High Pressure ! Who Wins the war ?

Monday AM: 11/9/09

Over the past several days, all eyes have been on Hurricane Ida, as she enters the GOM, and is heading northward as a weak Cat 1 Hurricane. My best estimate on this tropical system is for Ida to make landfall near Pensacola Florida during early Tuesday morning. I'm forecasting Ida to make landfall as a tropical storm, with max sustained winds of 60 MPH. Very heavy rain can be expected from the central and Eastern Gulf States, and into much of the SE States, from later Monday into midweek.

For our regions, here in the Northern M/A and The Delaware Valley, comes some tricky forecasting with this storm, and deciding just where the remnants of Ida will go over the next several days. I don't want to get into model details, as most global models are all over the place with this storm. So this is where I as a forecaster, have to make some key decisions and make a call for what I see synoptically and pull out all the stops. I'll start off saying I have high confidence that much of the SE States will see a heavy rain event, with a general 2.00" to 4.00" of rain and some areas could see up to 5.00" and 6.00" amounts especially over SC and central and Eastern parts of NC. So expect a wind whipped rainstorm from Monday night through Wednesday for the SE States.

After Ida makes landfall early Tuesday morning, the storm will weaken to a tropical depression rather quickly, then head ENE to the SC coast for Wednesday, and just offshore on Thursday. Plenty of moisture will be ejected northward well ahead of this storm, and effect parts of the M/A states, mainly east of the Apps, for Tuesday night into Thursday morning. Strong High pressure will begin moving east from the Great Lakes region on Tuesday and Wednesday, then eastward to New England on Thursday. This strong High, will prevent this storm from moving up the coast, and keep it at bay, off the Carolina coast. Many areas from near PHL to NYC and points north and west, will see little if any precip from this storm, as Strong High pressure wins the battle.

The Coastal and southern/central parts of the M/A States will see some strong winds and periods of heavy rain, from Tuesday into Thursday morning. The heaviest rains will fall from Southern/Coastal VA into SE MD and The Delmarva. Many of these areas will see 1.00" to perhaps 3.00" of rain. A swath of .25" to 1.00" of rain will fall from The Chesapeake Bay region into much of DE and NE into Southern NJ and coastal central NJ. All areas near and just north and west from DCA to PHL and NYC, will see only a few periods of rain and < .25" of rain.

So for The Delaware Valley Region:
Tuesday Night into Wednesday Night.

I'm forecasting some periods of rain and gusty winds for DE and much of Southern NJ. This will mainly be from later Tuesday night into Wednesday night. Winds will be North and NE at 15 to 25 MPH and gusty, but winds of 20 to 35 MPH can be expected for the DE and SJ coastal areas. Rainfall amounts of .25" to 1.00" can be expected, with the highest amounts over coastal DE, and Extreme Southern NJ.

For NE MD into SE PA and Central and Northern NJ, a few periods of rain and quite breezy for Wed and Wed Night. Rainfall amounts of .25 or less can be expected. Temps on Wednesday will be quite chilly with highs mainly in the upper 40's to low 50's and stiff northerly winds of generally 15 to 25 MPH throughout the region.

I'll update this forecast if needed during Tuesday Evening.

Take Care,

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