DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 150436
SWODY1
SPC AC 150434

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1134 PM CDT THU MAR 14 2013

VALID 151200Z - 161200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

MODEL CONSENSUS IS THAT UPPER PATTERN WILL UNDERGO DEAMPLIFICATION
DURING THE DAY FRIDAY...BECOMING QUASI-ZONAL WITH TIME. SHORTWAVE
TROUGH NOW ENTERING THE PACIFIC NW WILL TURN SEWD AFTER CRESTING
UPPER RIDGE AND CONTINUE ESEWD THROUGH THE UPPER MS VALLEY AND GREAT
LAKES REGION. AT THE SFC A COLD FRONT WILL SETTLE SWD THROUGH THE
NRN/CNTRL PLAINS AND GREAT LAKES...WHILE A WARM FRONT SHIFTS EWD
THROUGH THE OH VALLEY.

...OH VALLEY...

FLOW OVER THE WRN GULF HAS RETURNED TO SLY. AS THE LARGE AREA OF
HIGH PRESSURE OVER THE NRN GULF SHIFTS EWD...AXIS OF MODIFIED CP AIR
WITH UPPER 40S TO NEAR 50 LOW-LEVEL DEWPOINTS WILL ADVECT THROUGH
THE LOW-MID MS VALLEYS. THIS MOISTURE WILL REACH THE OH VALLEY BY
FRIDAY NIGHT SUPPORTED BY A STRENGTHENING WSWLY LLJ. A PLUME OF
STEEPER MID-LEVEL LAPSE RATES IS EXPECTED TO ADVECT EWD ABOVE THE
AXIS OF MODEST LOW-LEVEL MOISTURE...CONTRIBUTING TO A CORRIDOR OF
MARGINAL ELEVATED INSTABILITY OVER A PORTION OF THE MID MS THROUGH
OH VALLEY FRIDAY NIGHT. INCREASING THETA-E ADVECTION AND ISENTROPIC
ASCENT WILL SUPPORT THE DEVELOPMENT OF A FEW THUNDERSTORMS OVERNIGHT
AS THE ATMOSPHERE DESTABILIZES. STEEPENING MID-LEVEL LAPSE
RATES...COLD TEMPERATURES ALOFT AND UP TO 40 KT UNIDIRECTIONAL SHEAR
THROUGH THE CONVECTIVE LAYER MIGHT SUPPORT SOME THREAT FOR
MARGINALLY SEVERE HAIL. MODEST INSTABILITY RESULTING FROM LIMITED
MOISTURE RETURN SHOULD SERVE AS AN OVERALL LIMITING FACTOR.

..DIAL/MOSIER.. 03/15/2013

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