Mesoscale Discussion 736

MESOSCALE DISCUSSION 0736
NWS STORM PREDICTION CENTER NORMAN OK
0640 PM CDT FRI APR 25 2008
AREAS AFFECTED...CENTRAL AND NRN AR...SRN MO
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 252340Z - 260045Z
SEVERE POTENTIAL APPEARS TO BE INCREASING WITHIN THE PAST 45
MINUTES. A WW MAY BE NEEDED IN THE NEXT HR.
DESPITE WIDESPREAD CLOUD COVER MOST OF THE DAY...THE AIRMASS ALONG
AND AHEAD OF THE COLD FRONT OVER CENTRAL AND NRN AR INTO SRN MO HAS
BECOME MARGINALLY UNSTABLE /500 - 900 J/KG MLCAPE/. WITH CONTINUED
CONVERGENCE ALONG THE FRONT...CONVECTIVE DEVELOPMENT SHOULD BE
MAINTAINED INTO THE EVENING HRS. DEEP LAYER SHEAR AROUND 40 KTS
SHOULD OVERSPREAD THE AREA THIS EVENING AS THE UPPER SYSTEM LIFTS
NEWD TOWARDS THE GRT LAKES. MORE UNCERTAIN IS IF QUASI-DISCRETE
STORMS CAN DEVELOP AND SUSTAIN THEMSELVES ALONG OR AHEAD OF THE
LINE. GIVEN MAGNITUDE OF LOW LEVEL SHEAR...150 - 250
M2/S2...POTENTIAL EXISTS FOR DEVELOPMENT OF LOW LEVEL MESOCYCLONES
IF STORMS CAN REMAIN ROOTED IN THE BOUNDARY LAYER AND NOT DECOUPLE
THIS EVENING. THE MAIN THREATS APPEAR TO BE LARGE HAIL AND DAMAGING
WINDS...BUT AN ISOLATED TORNADO CANNOT BE RULED OUT.
..SMITH.. 04/25/2008