DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 121237
SWODY1
SPC AC 121235

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0735 AM CDT WED SEP 12 2012

VALID 121300Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
PRIMARY FEATURE IS A LARGE UPPER LEVEL TROUGH...WITH TWO SHORTWAVE
TROUGHS EMBEDDED WITHIN...WHICH WILL PROGRESS EWD ACROSS CNTRL
CANADA. ONE SHORTWAVE TROUGH WILL PROGRESS NEWD FROM NRN MB INTO FAR
NRN QC WHILE THE OTHER DROPS SEWD THROUGH SK AND INTO THE NRN
PLAINS. ANOTHER WEAK SHORTWAVE...WEAKLY PHASED WITH THE MEAN
CANADIAN TROUGH...WILL MOVE EWD ACROSS THE FOUR CORNERS AND INTO THE
CNTRL/SRN ROCKIES. A TRAILING COLD FRONT ASSOCIATED WITH THE NRN MB
SHORTWAVE WILL CONTINUE TO MOVE SEWD ACROSS THE CNTRL PLAINS/UPPER
MS VALLEY WHILE HIGH PRESSURE AT THE SFC AND ALOFT REMAINS OVER THE
ERN STATES.

...S-CNTRL PLAINS...
MODEST LOW-LEVEL MOISTURE RETURN IS EXPECTED AHEAD OF THE COLD WITH
AFTERNOON DEWPOINTS GENERALLY IN THE MID-50S. WEAKER SLY FLOW AND
THE PRESENCE OF A LEE TROUGH WILL LIKELY ENHANCE THE SWD PROGRESSION
OF THE COLD FRONT ACROSS THE CNTRL/SRN HIGH PLAINS. AS A
RESULT...THE COLD FRONT WILL LIKELY INTERACT WITH THIS MODERATELY
MOIST AIR MASS AROUND PEAK HEATING ACROSS THE TX/OK
PANHANDLES...NWRN OK...AND S-CNTRL KS. THE AIR MASS OVER THIS REGION
IS EXPECTED TO BE DEEPLY MIXED /LCLS AROUND 9 KFT/ BUT THE INCREASED
LOW-LEVEL MOISTURE SHOULD ALLOW FOR AT LEAST MARGINAL INSTABILITY.
MODEL FORECAST SOUNDINGS GENERALLY DEPICT MLCAPE AOB 500 J/KG WHICH
IS PREDICATED ON DRY ADIABATIC PROFILES THROUGH ABOUT 700 MB. AS
SUCH...CLOUD COVER ASSOCIATED WITH THE SHORTWAVE TROUGH APPROACHING
FROM THE W MAY ACT TO LIMIT HEATING AND MIXING...WHICH WOULD LIKELY
KEEP MUCH OF THE AREA FREE OF CONVECTION. IF THE PROFILES DO
MIX...LARGE TEMPERATURE/DEWPOINT SPREADS WOULD PROMOTE AN ISOLATED
THREAT FOR STRONG/SEVERE WIND GUSTS.

...SRN ROCKIES...
LARGE SCALE LIFT ASSOCIATED WITH THE SHORTWAVE TROUGH MOVING THROUGH
THE REGION WILL INTERACT WITH A MOIST AIR MASS TO PROMOTE SCATTERED
TO NUMEROUS TSTMS FROM THE FOUR CORNERS EWD INTO THE SRN ROCKIES.
THE PRIMARY THREAT WITH THESE TSTMS SHOULD BE HEAVY RAIN BUT A FEW
STRONG GUSTS MAY OCCUR AS UPDRAFTS BRIEFLY STRENGTHEN AND INCREASE
PRECIPITATION LOADING...ESPECIALLY ACROSS THE SRN ROCKIES WHERE NELY
FLOW ASSOCIATED WITH THE COLD FRONT COULD INCREASE LOW-LEVEL
CONVERGENCE. ATTM THE OVERALL SEVERE THREAT IS TOO LOW TO WARRANT
ANY SEVERE PROBABILITIES.

..MOSIER.. 09/12/2012

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