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SPC MD 1141

MD 1141 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN AND EASTERN VA...SOUTHERN MD...AND THE DELMARVA PENINSULA
MD 1141 Image


Mesoscale Discussion 1141
NWS Storm Prediction Center Norman OK
0157 AM CDT Mon Jul 23 2018

Areas affected...Southern and eastern VA...southern MD...and the
Delmarva Peninsula

Concerning...Severe potential...Watch unlikely 

Valid 230657Z - 230930Z

Probability of Watch Issuance...5 percent

SUMMARY...A marginal severe-weather threat exists during the
remaining part of the overnight into the early morning, spreading
from southern through eastern Virginia, southern Maryland and part
of the Delmarva Peninsula.  Isolated strong and damaging wind gusts
producing primarily tree damage should be the greatest impact, while
downburst wind speeds are expected to be mainly sub-severe.

DISCUSSION...At 0650Z, mosaic radar imagery and lightning data
showed clusters of storms tracking north across central and eastern
NC to the extreme southeast VA coast.  Despite weak deep-layer lapse
rates, the presence of high moisture-content air (surface mixing
ratios exceeding 15-17 g/kg and precipitable water 1.7-2 inches) is
contributing to a moderately unstable environment.  Meanwhile,
water-vapor imagery indicated a compact midlevel circulation
centered across western NC, while area VWP data showed stronger
southerly midlevel winds across eastern NC into central/eastern VA. 
Forcing for ascent within the eastern periphery of the western NC
circulation and a northward-moving embedded lobe of vorticity will
continue to support thunderstorm development into the early morning
across southern into central VA and parts of MD and the Delmarva. 
Although sufficient shear and moderate instability will allow for
organized storms, the presence of aforementioned weak lapse rates
will inhibit sustained updrafts and should preclude severe wind
gusts reaching the surface.

..Peters/Edwards.. 07/23/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PHI...AKQ...LWX...RNK...

LAT...LON   36577896 37367898 38297841 38867794 39067737 39027616
            38757526 38427508 37077554 36567588 36577896 

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