DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 241249
SWODY1
SPC AC 241247

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT FRI AUG 24 2012

VALID 241300Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR
PARTS OF THE CENTRAL DAKOTAS...

...NRN PLAINS THIS AFTERNOON/EVENING...
A PRONOUNCED MIDLEVEL SHORTWAVE TROUGH OVER THE NRN ROCKIES THIS
MORNING WILL PROGRESS EWD OVER MT/ND BY EARLY SATURDAY. STRONG
CYCLOGENESIS IS EXPECTED IN ADVANCE OF THE MIDLEVEL WAVE...AS AN
INITIAL LEE CYCLONE DEVELOPS EWD FROM ERN MT INTO WRN ND TODAY...AND
THEN NNEWD INTO MB AND OCCLUDES OVERNIGHT. AN ASSOCIATED COLD FRONT
WILL LIKEWISE MOVE EWD ACROSS THE NRN HIGH PLAINS THIS
EVENING...REACHING THE ERN DAKOTAS BY EARLY SATURDAY. THE COLD
FRONT IS EXPECTED TO BE THE PRIMARY FOCUS FOR STRONG/SEVERE
THUNDERSTORM DEVELOPMENT THIS AFTERNOON/EVENING.

EARLIER CONCERNS REGARDING CLOUD COVER AND MOISTURE RETURN ARE STILL
VALID. ELEVATED CONVECTION PERSISTS AS OF 12Z ACROSS SW/CENTRAL ND
IN ASSOCIATION WITH LOW-LEVEL WAA AND A LEAD SPEED MAX ALOFT. THE
CLOUDS WILL INTERFERE WITH DAYTIME HEATING ACROSS PARTS OF
CENTRAL/NRN ND...THOUGH SOME CLEARING FROM THE W WILL BE POSSIBLE
THIS AFTERNOON IMMEDIATELY IN ADVANCE OF THE COLD FRONT.
ADDITIONALLY...THE RICHER LOW-LEVEL MOISTURE IS CONFINED MUCH
FARTHER TO THE S ACROSS THE CENTRAL/SRN PLAINS. THE LOW-LEVEL MOIST
LAYER IS RATHER SHALLOW IN SD WHERE THE LOW 60S SURFACE DEWPOINTS
RESIDE...AND THIS MOISTURE WILL BE SUSCEPTIBLE TO VERTICAL MIXING AS
SURFACE TEMPERATURES WARM RAPIDLY TO THE S OF THE CLOUDS IN ND.
THUS...THERMODYNAMIC PROFILES APPEAR MOST SUPPORTIVE OF SOMEWHAT
HIGH-BASED STORMS ALONG THE FRONT THIS AFTERNOON AND CONTINUING INTO
THIS EVENING. A MIX OF CELLS AND LINE SEGMENTS...IN AN ENVIRONMENT
WITH 0-6 KM BULK SHEAR NEAR 40 KT...WILL SUPPORT A RISK FOR AT LEAST
ISOLATED DAMAGING WINDS AND LARGE HAIL.

...CENTRAL/SRN HIGH PLAINS THIS AFTERNOON/EVENING...
AN INITIAL BAND OF CONVECTION AND AN ASSOCIATED MCV ARE MOVING EWD
ACROSS CENTRAL KS AND WRN OK...TO THE E OF THE PRIMARY MIDLEVEL
TROUGH OVER NM/CO. CLOUD BREAKS AND SURFACE HEATING W OF THE
MORNING CONVECTION...AS WELL AS A CORRIDOR OF LOW-MID 60S BOUNDARY
LAYER DEWPOINTS E OF THE LEE TROUGH...WILL CONTRIBUTE TO AFTERNOON
MLCAPE NEAR 1500 J/KG. THIS BUOYANCY AND BACKGROUND ASCENT/
WEAKENING CIN...COMBINED WITH EFFECTIVE BULK SHEAR APPROACHING 25
KT...COULD SUPPORT A FEW STORMS CAPABLE OF PRODUCING STRONG OUTFLOW
GUSTS.

..THOMPSON/COHEN.. 08/24/2012

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