Mesoscale Discussion #746

MESOSCALE DISCUSSION 0746
NWS STORM PREDICTION CENTER NORMAN OK
0933 PM CDT SAT APR 26 2008

AREAS AFFECTED…WEST TX

CONCERNING…SEVERE THUNDERSTORM WATCH 239…

VALID 270233Z – 270400Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 239
CONTINUES.

THE ISOLATED SEVERE THREAT ACROSS THE CNTRL AND NRN PART OF WW 239
SHOULD SLOWLY MOVE ESEWD LATE THIS EVENING. LARGE HAIL AND ISOLATED
DAMAGING WINDS SHOULD BE THE PRIMARY THREATS. ATTM…UNCERTAINTY
REMAINS CONCERNING WHETHER AN ADDITIONAL WATCH WILL BE NEEDED EAST
OF THE CURRENT WW.

LATEST SFC ANALYSIS SHOWS MID 50S F DEWPOINTS ADVECTING WWD ACROSS
THE LOW ROLLING PLAINS EAST OF LUBBOCK. THIS IS LIKELY CONTRIBUTING
TO INCREASING INSTABILITY ACROSS WEST TX WHERE OBJECTIVE ANALYSIS
SHOWS AN AXIS WITH MLCAPE OF 1500 TO 3000 J/KG. IN
ADDITION…FORECAST SOUNDINGS AND RUC ANALYSIS HAVE INCREASED
VERTICAL SHEAR ACROSS THE REGION WHICH MAY BE DUE TO THE PASSAGE OF
A SUBTLE SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY OVER NCNTRL
TX. THE INCREASING INSTABILITY AND VERTICAL SHEAR ALONG WITH STEEP
MID-LEVEL LAPSE RATES EXCEEDING 8.0 C/KM ON THE DEL RIO AND MIDLAND
SOUNDINGS MAY SUPPORT A CONTINUED THREAT FOR LARGE HAIL. ISOLATED
WIND DAMAGE WILL ALSO BE POSSIBLE ESPECIALLY AS THE LOW-LEVELS
CONTINUE TO MOISTEN OVER THE NEXT FEW HOURS.

..BROYLES.. 04/27/2008