Friday, March 21, 2014

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 211253
SWODY1
SPC AC 211252

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT FRI MAR 21 2014

VALID 211300Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

THE MID TO UPPER-LEVEL PATTERN WILL REMAIN QUASI ZONAL OVER THE
CONUS WITH THE MOST PROMINENT FEATURE BEING AN POLAR-BRANCH
SHORT-WAVE TROUGH WHICH WILL TRANSLATE FROM THE UPPER MS VALLEY TO
LOWER GREAT LAKES. AT THE SURFACE...12Z MESOANALYSIS SHOWED A COUPLE
OF COLD FRONTS...ONE FROM LOW PRESSURE OVER THE UPPER MS VALLEY INTO
THE NRN HIGH PLAINS...AND ANOTHER FROM A CYCLONE OVER S-CNTRL KS
INTO THE CNTRL ROCKIES. BOTH OF THESE COLD FRONTS WILL ADVANCE
EQUATORWARD IN THE WAKE OF THE GREAT LAKES SHORT-WAVE TROUGH WITH
THE SRN-MOST CONTRIBUTING TO CONVECTIVE DEVELOPMENT OVER THE RED
RIVER VALLEY BY LATE AFTERNOON OR EVENING INTO THE OVERNIGHT
HOURS.

...RED RIVER VALLEY LATE THIS AFTERNOON INTO EVENING...

12Z REGIONAL SOUNDINGS CONFIRM THAT CAPPING ASSOCIATED WITH A
WELL-DEFINED EML WILL REMAIN PROBLEMATIC TO VIGOROUS SURFACE-BASED
STORM DEVELOPMENT ALONG THE COLD FRONT LATER TODAY. LATEST MODEL
GUIDANCE SUGGESTS THAT TSTMS WILL BECOME INCREASINGLY POSSIBLE BY
LATE AFTERNOON OVER S-CNTRL/SERN OK AS DAYTIME HEATING COMBINES WITH
CONVERGENCE ALONG THE FRONT TO LOCALLY OVERCOME THE CAP. SUBSEQUENT
STORMS MAY EVOLVE THIS EVENING ALONG OR IN THE IMMEDIATE WAKE OF THE
FRONT FROM SRN OK/NRN TX INTO AR.

THE WARMTH OF THE CAP RELATIVE TO THE MARGINAL BOUNDARY LAYER
MOISTURE CONTENT WILL LIMIT THE DEGREE OF AIR MASS DESTABILIZATION
WITH MUCAPE VALUES REMAINING LESS THAN 1000 J/KG. WHEN COUPLED WITH
EFFECTIVE BULK SHEAR OF ONLY 30-35 KT...THE POTENTIAL FOR INTENSE
UPDRAFTS AND ASSOCIATED SEVERE WEATHER APPEARS TOO MARGINAL TO
WARRANT PROBABILITIES.

..MEAD/LEITMAN.. 03/21/2014

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