MESOSCALE DISCUSSION 0377
   NWS STORM PREDICTION CENTER NORMAN OK
   1243 PM CDT SUN APR 19 2015

   AREAS AFFECTED...CENTRAL AND EASTERN OK...SOUTHEAST KS...SOUTHWEST
   MO...AND WESTERN AR

   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

   VALID 191743Z - 191945Z

   PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   SUMMARY...ISOLATED THUNDERSTORMS ACROSS NORTHWEST OK INTO
   SOUTH-CENTRAL KS MAY PRODUCE MARGINALLY SEVERE HAIL.
   OTHERWISE...THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS CENTRAL AND
   EASTERN OK BY 20Z AND TRACK EAST TOWARD WESTERN AR. LARGE HAIL AND
   STRONG WINDS WILL BE THE MAIN THREAT...BUT A TORNADO OR TWO ALSO
   WILL BE POSSIBLE. THIS AREA IS BEING MONITORED FOR WATCH ISSUANCE BY
   20Z.

   DISCUSSION...THUNDERSTORMS HAD DEVELOPED BENEATH THE UPPER LOW IN A
   STEEP LAPSE RATE...WEAKLY UNSTABLE AIRMASS ACROSS NORTHWEST OK INTO
   SOUTH-CENTRAL KS. THESE INITIAL STORMS MAY POSE A MARGINALLY SEVERE
   HAIL AND GUSTY WIND THREAT. FURTHER EAST...A COLD FRONT STRETCHED
   FROM EASTERN KS THROUGH CENTRAL OK INTO NORTH TX. NEAR AND AHEAD OF
   THE FRONT...SCATTERED AGITATED CU HAVE DEVELOPED AS DAYTIME HEATING
   HAS RESULTED IN WEAK DESTABILIZATION AND AN ERODING CAP. INSTABILITY
   SHOULD INCREASE WITH CONTINUED HEATING THIS AFTERNOON. VERY STEEP
   LAPSE RATES /7 TO 8 DEG C PER KM/ PER 12Z RAOBS FROM OUN AND FWD
   INDICATE LARGE HAIL WILL BE THE MAIN THREAT. STRONG WINDS MAY
   ACCOMPANY STORMS AS WELL. WHILE GENERALLY WEST/SOUTHWESTERLY
   VERTICAL WIND PROFILES AND WEAK CONVERGENCE ALONG THE FRONT WILL
   FAVOR UPSCALE GROWTH AND/OR BOWING LINE SEGMENTS...A TORNADO OR TWO
   CAN NOT BE RULED OUT EARLY ON WITH ANY CELLS THAT CAN REMAIN
   DISCRETE DUE TO THE AMBIENT VORTICITY BENEATH THE UPPER LOW. THE MCD
   AREA WILL CONTINUE TO BE MONITORED FOR WATCH ISSUANCE BY 20Z.

   ..LEITMAN/HART.. 04/19/2015


   ATTN...WFO...LZK...SGF...SHV...TSA...ICT...FWD...OUN...

   LAT...LON   33419325 34379300 35439299 36239323 37049385 37749516
               37829651 37399781 36839843 36329865 35399869 34509821
               34149784 33559641 33219461 33159366 33419325