May 20, 2014 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   1258 AM CDT TUE MAY 20 2014

   VALID 201200Z - 211200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID TO
   UPPER MS VALLEY AND OH VALLEY...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL HIGH
   PLAINS...

   ...SUMMARY...
   SEVERE THUNDERSTORMS WITH WIND DAMAGE AND HAIL ARE EXPECTED TO
   DEVELOP ACROSS THE MID TO UPPER MISSISSIPPI VALLEY EXTENDING EAST
   SOUTHEASTWARD INTO THE OHIO VALLEY. OTHER SEVERE STORMS WITH LARGE
   HAIL AND ISOLATED WIND DAMAGE SHOULD DEVELOP IN THE CENTRAL HIGH
   PLAINS.

   ...MID TO UPPER MS VALLEY/OH VALLEY...
   AN UPPER-LEVEL RIDGE WILL BUILD ACROSS THE LOWER TO MID MS VALLEY
   TODAY AS AN UPPER-LEVEL TROUGH MOVES INTO THE UPPER MS VALLEY. AT
   THE SFC...SLY TO SWLY WINDS WILL BE IN PLACE ACROSS THE MID MS
   VALLEY EWD INTO THE OH VALLEY WHICH WILL ALLOW LOW-LEVEL MOISTURE TO
   INCREASE THROUGHOUT THE DAY. AS A RESULT...SFC DEWPOINTS MAY REACH
   THE LOWER 60S F ACROSS PARTS OF THE SLIGHT RISK AREA ENABLING A
   CORRIDOR OF MODERATE INSTABILITY TO DEVELOP FROM THE MID TO UPPER MS
   VALLEY EWD INTO THE OH VALLEY. THUNDERSTORMS APPEAR MOST LIKELY TO
   INITIATE BY LATE AFTERNOON NEAR A SFC TROUGH IN ERN IA AND NWRN IL.
   THIS ACTIVITY MAY ORGANIZE INTO A LINEAR MCS...MOVING ESEWD ACROSS
   THE OH VALLEY FROM LATE THIS AFTERNOON INTO THE EVENING.

   NAM FORECAST SOUNDINGS AT 00Z/WED FROM PEORIA IL ESEWD TO NEAR
   DAYTON OH SHOW MLCAPE OF 2000 TO 2500 J/KG WITH STEEP MID-LEVEL
   LAPSE RATES AND 0-6 KM SHEAR AROUND 50 KT. THIS SHOULD INITIALLY
   SUPPORT SUPERCELL DEVELOPMENT AS CELLS INITIATE ALONG THE
   INSTABILITY AXIS LATE THIS AFTERNOON. HAILSTONES OF GREATER THAN 2
   INCHES IN DIAMETER WITH BE POSSIBLE WITH SUPERCELLS. AS STORM
   COVERAGE INCREASES LATE THIS AFTERNOON...A TRANSITION TO LINEAR MODE
   SHOULD OCCUR AS A FORWARD-PROPAGATING WIND PRODUCING MCS ORGANIZES
   ACROSS THE WRN PART OF THE SLIGHT RISK AREA. THIS LINE OF STORMS IS
   EXPECTED TO MOVE ESEWD ACROSS NRN IL...NRN IND REACHING CNTRL OH BY
   EARLY TO MID EVENING. AN ENHANCED WIND DAMAGE THREAT MAY DEVELOP
   ALONG THIS CORRIDOR.

   ...CNTRL HIGH PLAINS...
   SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE CNTRL HIGH PLAINS TODAY.
   AT THE SFC...A LOW WILL REMAIN IN PLACE ACROSS THE CNTRL PLAINS AS
   UPSLOPE FLOW DEVELOPS ACROSS THE CNTRL HIGH PLAINS. A NARROW
   CORRIDOR OF LOW-LEVEL MOISTURE WILL EXTEND NWWD ACROSS NE CO AND SE
   WY WHERE SFC DEWPOINTS SHOULD BE NEAR 50 F. AS INSTABILITY DEVELOPS
   THIS AFTERNOON...THUNDERSTORMS SHOULD INITIATE ON THE CHEYENNE RIDGE
   AND MOVE SEWD INTO NERN CO. A CLUSTER OF STORMS MAY PERSIST INTO THE
   EARLY EVENING EVENTUALLY REACHING FAR NW KS.

   FORECAST SOUNDINGS AT 00Z/WED FOR AKRON CO SHOW MLCAPE NEAR 1000
   J/KG WITH 45 TO 50 KT OF 0-6 KM SHEAR. THIS COMBINED WITH STEEP
   LAPSE RATES AND VEERING WINDS WITH HEIGHT FROM THE SFC TO 500 MB
   SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. HAILSTONES OF
   GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE WITH THE MORE
   INTENSE CELLS. 0-3 KM LAPSE RATES OF 8.5 TO 9.0 C/KM SHOULD ALSO
   ENHANCE DOWNDRAFT ACCELERATION MAKING DAMAGING WIND GUSTS POSSIBLE
   AS WELL