Mid-Atlantic Discussion – Aug 3, 2011

So… here we are a month after the last Mid-Atlantic write-up (the event failed, BTW) with a new threat and different variables as we look at tomorrow’s severe weather.

Gonna just list the pros and cons and go from there:

PROS:
– Good low-level speed and directional shear.
– Excellent low-level lapse rates.
– Upper-level support via 500mb vort. max and some influence from the jet.
– Winds are veering throughout the column.

CONS:
– Possible cloud cover from storms to the northwest could inhibit heating.
– Lackluster mid-level lapse rates (could change for the better if dynamics are stronger).
– Upper-level jet is perhaps too far away to have a significant impact and we are not in the ideal (upper-level divergence) part of the jet.
– Main line of storms could come in just a bit too early for optimal destablization.
– High LCLs.

With everything put together, it looks like a pretty mixed bag between meh and awesome. I’m going to put tomorrow’s chasing chances at 50%… some nowcasting is definitely for tomorrow’s storms, so there’s no reason to decide on anything now. No idea where I’m going to go yet, either (should I end up going). Primary threat is wind… could see a tornado or two out of it if the instability is good enough.

SPC’s thoughts:

…MID ATLANTIC REGION…
A RATHER STRONG SHORTWAVE TROUGH NOW OVER THE DAKOTAS WILL TRACK
ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES ON
WEDNESDAY. SEVERAL CLUSTERS OF THUNDERSTORMS ARE ONGOING TODAY WITH
THIS FEATURE…AND WILL LIKELY PERSIST INTO TOMORROW. MODEL
GUIDANCE SUGGESTS THESE CONVECTIVE CLUSTERS WILL BE OVER PARTS OF
LOWER MI/NY/PA/OH AT 12Z. THERE IS CONSIDERABLE UNCERTAINTY
REGARDING THE EXTENT OF CLOUD COVER AHEAD OF THE STORMS…WHICH WILL
IMPACT THE DEGREE OF AFTERNOON DESTABILIZATION OVER THE MID ATLANTIC
REGION. HOWEVER…RATHER STRONG LOW AND MID LEVEL WIND FIELDS
ASSOCIATED WITH THE UPPER TROUGH POSE SUFFICIENT CONCERN TO INCLUDE
THIS REGION IN A SLIGHT RISK FOR SEVERE STORMS. THE MOST LIKELY
THREAT WOULD BE AN ORGANIZED MCS TRACKING THROUGH THE AREA DURING
THE AFTERNOON PRODUCING LOCALLY DAMAGING WIND GUSTS.


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