Friday's Threat For Severe Storms

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Friday will be another interesting day across the Mid Atlantic as another impulse of energy will drop out of Canada, raising heights and triggering a scattered late day severe thunderstorms.

The Day 2 SPC forecast has placed Philadelphia Baltimore DC Scranton NYC and Lancaster PA (to name a few big cities) under the slight risk category for severe weather.  While the wording is "slight" think elevated risk or higher than normal potential.

Here is the Day 2 Prediction via SPC. I will show my risk area in a map below.

The area is not surprisingly ripe for severe considering it has been on the warm sector of the stubborn stationary front that has divided the east between summer like warmth to late fall like temperatures.  Since we are more than 24 hours out I will headline the SREF model showing the probabilities to some of our severe weather parameters.

The first image to show you is the probability of having sufficient moisture to aid in the instability process for creating these storms.  The SREF is almost at 100% showing DP or Dewpoint values of greater than 55% which would be enough to support thunderstorms.  I however, ran the model at greater than 65 to see if we could have an environment conducive for any storm to turn severe storms.  The model does depict a 50/50 split of DP values over 65 away from the coast stretching from Cecil Co MD to Rockland CO NY.

The lifted index parameter per the SREF shows a 90% likelihood of greater than a L. I. Value of -2 while a 70% prob shows up for a L. I Value of greater than -4.  Anything of -2 will create enough lift to pop a few storms ... while a -4 will allow for the strongest updraft leading to multiple severe storms.

Finally, the CAPE value on SREF shows a 70% likelihood of CAPE values in the risk area hitting greater than 1000J/KG.  This would be ideal for strong to severe thunderstorms.


















Any windshear is anticipated to be situated over extreme NNJ, NEPA, and SENY where values show a 40% likelihood of >40KTS.  So any tornado threat will be slightly possible over this region.


HERE IS MY RISK AREA.  NOTE THE ORANGE OUTLINED AREA.  THIS IS WHERE I THINK THE BEST SHOT OF SEVERE STORMS WILL BE WHILE THE YELLOW HIGHLIGHTS THE RISK REGION.

YELLOW= STRONG STORMS ORANGE= SEVERE STORMS