000
ACUS01 KWNS 230554
SWODY1
SPC AC 230552

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1252 AM CDT THU MAY 23 2013

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN HIGH
PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NERN
STATES...

...SYNOPSIS...

BLOCKING UPPER PATTERN WILL PERSIST THURSDAY. UPPER LOW OVER THE
MID-UPPER MS VALLEY WILL ADVANCE THROUGH THE OH VALLEY...WHILE
ANOTHER TROUGH AMPLIFIES SWD INTO THE GREAT LAKES REGION. CLOSED
UPPER LOW OVER THE WRN STATES WILL DRIFT ONLY SLOWLY EWD...WHILE AN
UPPER RIDGE BUILDS ACROSS THE CNTRL STATES. AT THE SFC A COLD FRONT
WILL MOVE THROUGH ERN PORTIONS OF THE OH VALLEY INTO THE ERN STATES.
TRAILING PORTION OF THIS BOUNDARY WILL LIFT NWD THROUGH NRN TX AND
OK...WHILE A DRYLINE BECOMES ESTABLISHED ACROSS WRN TX.

...SRN HIGH PLAINS...

CURRENT INDICATIONS ARE THAT ELEVATED STORMS WILL DEVELOP EARLY
THURSDAY ACROSS NWRN TX INTO SWRN AND CNTRL OK WHERE THE NOCTURNAL
LLJ WILL AUGMENT WARM ADVECTION AND ISENTROPIC ASCENT NORTH OF THE
RETREATING BOUNDARY. RICHER LOW LEVEL MOISTURE WITH 60S DEWPOINTS
WILL ADVECT NWWD THROUGH THE SRN PLAINS WARM SECTOR BENEATH STEEP
LAPSE RATES. STRONG DIABATIC WARMING IS LIKELY SOUTH OF ONGOING
CONVECTION ACROSS NWRN AND WRN TX...WHICH ALONG WITH INCREASING
LOW-LEVEL MOISTURE WILL RESULT IN 2500-3000 J/KG MLCAPE DURING THE
AFTERNOON. STORMS ARE EXPECTED TO DEVELOP BY MID-LATE AFTERNOON IN
VICINITY OF THE DRYLINE/FRONT INTERSECTION OVER NWRN TX...AS WELL AS
SOME DISTANCE SWD INTO THE HIGH PLAINS. RIDGING ALOFT WITH MODEST
UPPER FLOW WILL TEMPER OVERALL SHEAR MAGNITUDES...BUT 30-35 KT
EFFECTIVE SHEAR AND STRONG INSTABILITY WILL BE SUFFICIENT FOR A FEW
SUPERCELLS WITH INITIAL STORMS THAT DEVELOP. PRIMARY THREAT WILL BE
VERY LARGE HAIL. A TORNADO OR TWO MAY ALSO BE POSSIBLE ESPECIALLY
DURING THE EARLY EVENING WHILE STORMS MAY STILL BE DISCRETE AND AS
THE LLJ INCREASES. STORMS MAY EVOLVE INTO AN MCS AND PROPAGATE SEWD
DURING THE EVENING WITH DAMAGING WIND BECOMING THE PRIMARY
THREAT...BEFORE ACTIVITY WEAKENS TOWARD MID-LATE EVENING.

...NERN STATES...

WIDESPREAD MULTILAYER CLOUDS ALONG CONVEYOR BELT WILL LIKELY LIMIT
DIABATIC WARMING AND OVERALL DESTABILIZATION POTENTIAL ACROSS MUCH
OF THE NERN STATES ON THURSDAY. HOWEVER...SOME CLOUD BREAKS WILL
LIKELY OCCUR AND MODEST DIABATIC WARMING OF THE MOIST BOUNDARY LAYER
WILL RESULT IN 500-1000 J/KG MLCAPE. BELT OF 35-40 KT MID-UPPER
LEVEL FLOW ALONG ERN PERIPHERY OF THE UPPER TROUGH WILL EXIST IN
WARM SECTOR RESULTING IN 30-40 KT EFFECTIVE SHEAR. STORMS MAY
UNDERGO A GRADUAL INTENSIFICATION WITH ORGANIZED MULTICELLS CAPABLE
OF PRODUCING MAINLY ISOLATED DAMAGING WIND. ANY SEVERE THREAT SHOULD
DIMINISH BY EARLY EVENING.

..DIAL/GUYER.. 05/23/2013