DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 190737
SWODY3
SPC AC 190735

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0235 AM CDT THU APR 19 2007

VALID 211200Z - 221200Z

..THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN PLAINS SSWWD INTO
THE SRN HIGH PLAINS...

..SYNOPSIS...
MODELS CONTINUE TO DEPICT THE LARGE WRN U.S. TROUGH CROSSING THE
ROCKIES AND REACHING THE PLAINS THIS PERIOD...THOUGH MODELS ARE AT
LEAST 6 HOURS SLOWER WITH THE EWD-PROGRESSION OF THIS FEATURE THAN
PRIOR RUNS.

AT THE SURFACE...PRESSURE FALLS WILL CONTINUE IN THE LEE OF THE
ROCKIES...WITH THE LOW/TROUGH PROGRESSING EWD OFF THE HIGH PLAINS
THROUGH THE END OF THE PERIOD.

..SRN HIGH PLAINS NNEWD INTO THE DAKOTAS/WRN MN...
QUESTIONS EXIST THIS PERIOD REGARDING DEGREE OF MOISTURE
RETURN...BUT EXPECT GENERALLY 50S DEWPOINTS TO ADVECT NWWD INTO THE
PLAINS. THIS SHOULD BE SUFFICIENT FOR THE DEVELOPMENT OF 500 TO
1000 J/KG MEAN-LAYER CAPE OVER THE HIGH PLAINS AND INTO NEB/SD.
HOWEVER...MODEST MOISTURE COMBINED WITH THE SLOWER MOVEMENT OF THE
UPPER TROUGH -- AND THUS STRONGER SUBSIDENCE/CAPPING BENEATH THE
UPPER RIDGE OVER MOST OF TX/OK/CENTRAL AND ERN KS -- SUGGESTS THAT
THE PRIMARY SEVERE THREAT SHOULD REMAIN CONFINED TO THE HIGH PLAINS.

FURTHER N...LOCATION AND DEGREE OF SEVERE THREAT WILL DEPEND UPON
INTENSITY OF THE LOW EVOLVING OVER THE CENTRAL HIGH PLAINS -- AND
THE RESULTING LOCATION OF THE NEWD-EXTENDING TROUGH/WARM FRONT.

ATTM...IT APPEARS THAT STRONG DEEP-LAYER SHEAR AND DEWPOINTS
GENERALLY IN THE MID 50S SHOULD SUPPORT THE DEVELOPMENT OF SUPERCELL
STORMS FROM THE CENTRAL AND SRN HIGH PLAINS NNEWD ACROSS THE WRN
HALF OF NEB AND INTO THE DAKOTAS AND PERHAPS WRN MN. GREATEST
THREAT WILL LIKELY EXIST FROM THE TX/OK PANHANDLES NWD ACROSS WRN
KS/ERN CO INTO THE WRN HALF OF NEB. IN THESE AREAS...LARGE HAIL AND
DAMAGING WINDS WILL BE POSSIBLE ALONG WITH ISOLATED TORNADOES.

THOUGH STORMS -- AND SOME SEVERE THREAT -- WILL SHIFT SLOWLY EWD
OVERNIGHT -- AND POSSIBLY TAKING ON A MORE LINEAR
ORGANIZATION...OVERALL EWD EXTENT OF THE THREAT WILL LIKELY BE
LIMITED DUE TO MODEST BOUNDARY-LAYER MOISTURE/OVERALL INSTABILITY.

.GOSS.. 04/19/2007

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