
MESOSCALE DISCUSSION 1234
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT FRI JUN 19 2009
AREAS AFFECTED...NERN KS / SERN NEB/ NRN MO / SRN INTO CNTRL IA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 191737Z - 191900Z
SEVERE STORMS ARE EXPECTED TO DEVELOP ALONG EWD-ADVANCING COLD FRONT
THIS AFTERNOON. A WW WILL LIKELY BE REQUIRED PRIOR TO 19-20Z.
LATEST MESOANALYSIS INDICATED SYNOPTIC COLD FRONT EXTENDING FROM LOW
PRESSURE OVER NWRN WI SWWD THROUGH CNTRL IA TO WEAKER...SECONDARY
LOW PRESSURE NEAR FNB. THE FRONT THEN TRAILED SWWD INTO CNTRL KS.
TSTMS HAVE SLOWLY BEEN INTENSIFYING ALONG OR PERHAPS JUST IN WAKE OF
COLD FRONT FROM W OF BIE TO NEAR OMA. THIS ACTIVITY APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF MORE SIGNIFICANT FORCING FOR
ASCENT ASSOCIATED WITH WELL-DEFINED SHORT WAVE TROUGH TRANSLATING
NEWD THROUGH WRN/CNTRL PARTS OF NEB/KS.
CONSIDERABLE CLOUDINESS AND RESIDUAL STABILIZING EFFECTS OF
NOCTURNAL CONVECTIVE OUTFLOW HAVE SLOWED THE RATE OF DESTABILIZATION
THIS MORNING WITHIN PRE-FRONTAL WARM SECTOR. HOWEVER...THE PRESENCE
OF 65-75 F BOUNDARY LAYER DEWPOINTS...CONTINUED INSOLATION AND
DYNAMIC MIDLEVEL COOLING ATTENDANT TO MID-LEVEL TROUGH SHOULD SERVE
TO HASTEN THE DESTABILIZATION PROCESS THIS AFTERNOON WITH MLCAPE
INCREASING TO 2000-4000 J/KG.
LARGELY UNIDIRECTIONAL DEEP...WSWLY FLOW PREVAILS FROM NERN KS EWD
THROUGH NRN MO...WHEREAS SURFACE WINDS OVER SRN/CNTRL IA HAVE
REMAINED MORE SLY/SELY...ENHANCING LOW-LEVEL HODOGRAPH CURVATURE.
THUS...WHILE BOWING CONVECTIVE STRUCTURES WILL LIKELY BE THE
DOMINANT MODE...SOME SUPERCELL POTENTIAL WILL EXIST OVER IA AS AIR
MASS DESTABILIZES IN WAKE OF EARLIER TSTM ACTIVITY. THE PRIMARY
SEVERE WEATHER THREATS WILL BE DAMAGING WINDS AND LARGE HAIL.
..MEAD.. 06/19/2009
ATTN...WFO...DVN...DMX...EAX...OAX...TOP...