DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 261730
SWODY2
SPC AC 261728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT THU SEP 26 2013

VALID 271200Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
CNTRL HIGH PLAINS...

...SRN AND CNTRL HIGH PLAINS...
AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE FOUR CORNERS REGION ON
FRIDAY AS A 60 TO 75 KT MID-LEVEL JET MOVES OUT ACROSS THE CNTRL
HIGH PLAINS. AT THE SFC...A LOW IS FORECAST TO DEEPEN ACROSS ERN CO
AND WRN KS AS A COLD FRONT MOVES THROUGH THE SRN ROCKIES. LOW-LEVEL
MOISTURE IS FORECAST TO INCREASE ACROSS THE TX PANHANDLE NWD INTO
WRN KS WHERE SFC DEWPOINTS SHOULD REACH THE LOWER TO MID 60S F BY
AFTERNOON. THIS SHOULD ENABLE MODERATE INSTABILITY TO DEVELOP BY
MID-AFTERNOON FROM WEST TX NWD INTO SW KS WITH THUNDERSTORMS
INITIATING ON THE WRN EDGE OF INSTABILITY AROUND 21Z. MODEL
FORECASTS ARE CONSISTENT MOVING THUNDERSTORMS EWD ACROSS WRN
KS...THE TX AND OK PANHANDLES AND WEST TX DURING THE LATE AFTERNOON
AND EARLY EVENING. MCS DEVELOPMENT WILL BE POSSIBLE FRIDAY EVENING.

FORECAST SOUNDINGS AT AMARILLO TX AND GARDEN CITY KS AT 00Z/SAT SHOW
MLCAPE IN THE 1200 TO 1500 J/KG RANGE WITH 45 TO 50 KT OF 0-6 KM
SHEAR. THIS ENVIRONMENT COMBINED WITH STEEP LAPSE RATES SHOULD
SUPPORT SUPERCELL DEVELOPMENT MAINLY WITH CELLS THAT REMAIN
DISCRETE. LARGE HAIL WILL BE POSSIBLE WITH ROTATING STORMS. CURVED
HODOGRAPHS EVIDENT ON FORECAST SOUNDINGS ALSO SUGGEST THAT A
POTENTIAL FOR TORNADOES WILL EXIST. THE MODELS MARKEDLY INCREASE
LOW-LEVEL CONVERGENCE ALONG THE WEST EDGE OF THE INSTABILITY AXIS
EARLY FRIDAY EVENING. THIS SHOULD CONTRIBUTE TO LINEAR DEVELOPMENT
WHERE THE GREATEST STORM COVERAGE OCCURS MAKING WIND DAMAGE THE MORE
DOMINANT THREAT. A WIND DAMAGE THREAT COULD CONTINUE INTO THE
MID-EVENING ESPECIALLY IF A LINEAR MCS CAN ORGANIZE.

...UPPER MS VALLEY...
SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE NRN PLAINS AND UPPER MS
VALLEY FRIDAY AS A COLD FRONT ADVANCES SEWD ACROSS THE ERN DAKOTAS.
SFC DEWPOINTS AHEAD OF THE FRONT SHOULD BE IN MID 50S TO LOWER 60S
F. THIS SHOULD ENABLE AN AXIS OF INSTABILITY TO DEVELOP ACROSS CNTRL
AND NRN MN SWWD INTO ERN SD FRIDAY AFTERNOON. THE MODELS SUGGEST
THAT STORMS WILL INITIATE ALONG THE INSTABILITY AXIS EARLY IN THE
DAY WITH ANOTHER BAND OF CONVECTION MOVING INTO THE REGION FROM THE
SOUTHWEST BY FRIDAY EVENING. FORECAST SOUNDINGS ACROSS CNTRL AND NRN
MN AT 00Z/SAT SHOW SBCAPE VALUES AROUND 500 J/KG WITH 40 TO 45 KT OF
0-6 KM SHEAR. THIS MAY BE ENOUGH FOR A MARGINAL SEVERE THREAT WITH
THE STRONGER UPDRAFTS. ISOLATED WIND DAMAGE WILL ALSO BE POSSIBLE
DURING THE LATE AFTERNOON AND EARLY EVENING WHEN INSTABILITY IS
FORECAST TO BE MAXIMIZED.

..BROYLES.. 09/26/2013

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