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Mesoscale Discussion 644
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   MESOSCALE DISCUSSION 0644
   NWS STORM PREDICTION CENTER NORMAN OK
   0822 PM CDT WED APR 27 2011
   
   AREAS AFFECTED...KY...IND...WRN AND CENTRAL OH...WRN WV...AND SWRN
   VA
   
   CONCERNING...TORNADO WATCH 239...242...
   
   VALID 280122Z - 280215Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 239...242...CONTINUES.
   
   EARLY-MID EVENING SURFACE ANALYSIS INDICATED AN AREA OF LOW PRESSURE
   CONTINUING TO TRACK NEWD INTO SWRN IND ALONG A QUASI-STATIONARY
   BOUNDARY WHICH EXTENDED NEWD ACROSS CENTRAL-ERN IND INTO NWRN OH. 
   MEANWHILE...A COLD FRONT TRAILED SWD FROM THE LOW THROUGH WRN TN
   INTO MS...BISECTING MS GENERALLY FROM NE-SW.
   
   CLOUDINESS ACROSS MUCH WW/S 239 AND 242 HAVE MITIGATED STRONGER
   INSTABILITY FROM DEVELOPING WITH THE GREATEST INSTABILITY /MUCAPE TO
   AROUND 1000 J PER KG/ EXTENDING ACROSS ERN KY INTO SRN OH.  THIS
   CORRIDOR OF INSTABILITY IS LOCATED ALONG A STRONG SLY LLJ /50-70 KT/
   WHICH WILL CONTINUE TO PROVIDE NWD MOISTURE ADVECTION/
   DESTABILIZATION INTO ERN KY/SRN OH DESPITE THE ONSET OF DIABATIC
   COOLING.  GREATEST SEVERE WEATHER THREAT THROUGH THE EVENING SHOULD
   BE CONFINED TO THE ERN HALF OF KY INTO PARTS OF SRN OH GIVEN THE
   AFOREMENTIONED FACTORS.  HOWEVER...AREAS FARTHER NW-N ALONG THE
   TRACK OF THE SURFACE LOW INTO IND WILL HAVE A CONDITIONAL TORNADO
   TREAT DESPITE WEAKER INSTABILITY.  ISALLOBARIC EFFECT OF THE SURFACE
   WINDS DUE TO SURFACE PRESSURE FALLS OVER IND INTO WRN KY SHOULD
   MAINTAIN A SELY COMPONENT AND ENHANCE LOW LEVEL SHEAR...ESPECIALLY
   ALONG AND ESE OF THE SURFACE LOW TRACK.
   
   ..PETERS.. 04/28/2011
   
   
   ATTN...WFO...RNK...RLX...CLE...MRX...JKL...ILN...LMK...IWX...
   OHX...IND...PAH...ILX...
   
   LAT...LON   36678708 36968758 38198723 38688755 40138747 40948636
               40998434 41138354 40898241 40358222 39408238 39008280
               38708252 38598160 38158105 37988077 37368131 36748140
               36558171 36588489 36678708 
   
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Page last modified: April 28, 2011
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