Severe Weather likely for portions of Eastern NY to VA for Saturday
Posted: (August 01, 2008 12:55 pm)

Eastern PA-NJ-DE-MD-VA

The WRF has increased the forcing associated with this front over the last few model runs and now shows a severe threat with a line of storms that push through early in the afternoon.  The trough aloft will be on a neutral axis with the strongest winds aloft rounding the base of the trough into the areas listed above.  The left front quad will help increase the forcing for storms to develop and organize into a line.  The wind profiles from the sfc to aloft are mainly westerly supporting the threat for storms to quickly develop in a line and push eastward.  A few bowing segments cannot be ruled out if storms can organize as it appears in recent model runs.  The best instability parameters will be in this area.

PHL- 3071j/kg
DCA- 2389j/kg
Trenton, NJ- 3200j/kg
Dover, DE- 3040j/kg

These values could be higher if storms can hold off until after the peak heating hours.  Right now it appears storms form and start to move in around noon-2pm.  The main threats will be for damaging winds and small hail.  Despite colder air aloft the hail threat will be cut down due to the abundant moisture.  Flash flooding will be a problem with storms dumping up to 1-2" in a short period of time.  The storms will be moving at a good pace and will not sit over an area.  Stronger storms that form could produce hail up to .75-1".
  

Eastern NY

The greatest threat for severe weather will be across this area with a sfc wave of low pressure backing the winds at the sfc.  Since this will locally enhance the shear profiles it supports the threat for an isolated tornado.  Forecast soundings pick up on this feature backing the sfc winds but since low level winds are relatively weak it will only allow for the slight chance of an isolated tornado.  Mid level temps will be slightly colder then areas below favoring an enhanced threat for large hail up to 1.5" in diameter.  The limitting factors for large hail will be less felt up this way since moisture will not be as abundant.  In addition to hail, damaging winds and an isolated tornado will be the other threats with the stronger storms that develop.  

-Stay alert tomorrow as this threat is increasing and could catch a few people by suprise.  Right now it appears the severe weather will be moving through anytime from noon-4pm.