DROUGHT WATCH IN EFFECT FOR NEW JERSEY

09/01/10  4:54 PM

High pressure once again produced an excellent day of weather, albeit hot but at least dry.  Temperatures rose into the upper 80′s to mid 90′s once again while humidity increased slightly from the previous few days.

All eyes of course are on Hurricane Earl.  The forecast for Hurricane Earl is very complicated but also rather simple to see.  Through today, Hurricane Earl has been under the influence of two main features.  The first is a strengthen ridge to the northeast and east, which is driving Earl to the northwest and the second is a strong upper low over the eastern Gulf of Mexico, which is enhancing the southeasterly flow.  This southeasterly flow is bad news for those along the Mid Atlantic coast.

The idea from the NHC and most model guidance as that Earl would reach the edge of the western Atlantic ridge, turn north around the North Carolina coastal waters, and exit into the Atlantic well east of New Jersey.  As you know, I was not and still not buying that forecast.  Let me explain why.

Besides looking at models, a meteorologist has to use his brain sometimes and actually look at the atmospheric set up using physics and some basic laws of meteorology.  Now, the first physics problem we have here on the water vapor satellite picture is that there is a lot of dry, sinking air over the Tennessee Valley.  This is important because this dry air is significantly slowing the cold front that is expected to force Earl well to the east of New Jersey.  This dry air is the result of two features.  The first is what we call a heat ridge or warm core ridge.  The second is what we call upper level wind convergence.  You see, the upper low over the Gulf Coast is creating wind convergence over the Tennessee Valley.  This convergence is slowly down the base of the trough, which means our cold front is going to be a little late to it’s date with Earl.  I know, Earl is going to be disappointed.

So where does this put us, the Northern Mid Atlantic?

Well, if my theory is right that Earl is going to move further west than guidance suggests, than Earl will pass 75W to the south of 30N, which would allow Earl to move through the Outer Banks of North Carolina and then due north towards the southern Delaware coast.  Eventually Earl will turn northeast and I have that happening over the New Jersey coastal waters, roughly 150 miles off the New Jersey coast.

At this time, the forecast I had for this morning remains the same with the most significant impacts along the immediate New Jersey coast and along the south shores of Long Island where Tropical Storm to near Hurricane strength winds can be expected, heavy rainfall, rough surf, and coastal flooding.  Further to the northwest over interior southern and central New Jersey, northeastern New Jersey, the New York City metropolitan area, and much of Connecticut, bands of heavy rain and strong winds will move through these regions, however the effects of Earl will not be a constant and I could not rule out some breaks of sun between the bands of rain.  Winds will remain in the Tropical Storm strength, but mostly towards 40 mph for a short times.  Further to the west, the cut off from the impacts of Earl will be sharp with little impact for Philadelphia, the Delaware River Valley, eastern Pennsylvania, interior New York and northern Connecticut.

Earl will exit into the Atlantic quickly along with a cold front on Friday night with clearing skies.  A cooler Polar air mass will take hold for Saturday and Sunday with temperatures falling back into the 70′s and lower 80′s.  By Monday though, lower to mid 80′s will take hold for much of the Northern Mid Atlantic.  High pressure will keep the region dry through early next week once Earl exits.

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