DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 061247
SWODY1
SPC AC 061244

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT SAT APR 06 2013

VALID 061300Z - 071200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A PROGRESSIVE...QUASI-ZONAL PATTERN WILL EXIST OVER THE CONUS
THROUGH THE D1 PERIOD. MULTIPLE VORTICITY MAXIMA ARE PRESENT WITHIN
THIS REGIME...THE MOST NOTABLE OF WHICH WILL TRANSLATE FROM THE NRN
PLAINS INTO THE UPPER GREAT LAKES BY SUNDAY MORNING. A SURFACE LOW
OVER SERN SD/SWRN MN AS OF 12Z WILL DEVELOP ENEWD IN TANDEM WITH
THIS VORTICITY MAXIMUM...WHILE A TRAILING COLD FRONT SETTLES SWD
THROUGH THE NRN PLAINS...UPPER MS VALLEY...AND UPPER MIDWEST.
A PRE-FRONTAL TROUGH --CURRENTLY FROM THE SURFACE LOW SWWD INTO THE
SRN HIGH PLAINS-- WILL MIGRATE EWD INTO THE OH VALLEY BY TONIGHT.

...UPPER MIDWEST INTO MID MS VALLEY...

DESPITE THE PRESENCE OF A RATHER DRY BOUNDARY LAYER...A PLUME OF
STEEP MIDLEVEL LAPSE RATES ADVECTING EWD FROM THE MID MO VALLEY WILL
COMBINE WITH DAYTIME HEATING TO YIELD A WEAKLY UNSTABLE AIR MASS
LATER TODAY AHEAD OF THE PRE-FRONTAL TROUGH. HEIGHT FALLS/DCVA
COUPLED WITH LOW-LEVEL CONVERGENCE INVOF OF THE SURFACE LOW AND
ASSOCIATED TROUGH WILL FOSTER A BAND OF SHOWERS AND WIDELY SCATTERED
TSTMS LATE THIS AFTERNOON FROM SRN WI TO E-CNTRL MO. THE STRONGEST
STORMS WILL BE CAPABLE OF GUSTY WINDS AND SMALL HAIL. EXPECT STORM
COVERAGE TO DECREASE BY LATE EVENING INTO TONIGHT AS THE BOUNDARY
LAYER COOLS AND STABILIZES.

...NRN INTERMOUNTAIN REGION...

A VORTICITY MAXIMUM CURRENTLY OVER WRN WA WILL TRANSLATE ENEWD
ACROSS THE REGION TODAY WITH AN ACCOMPANYING POCKET OF COLD MIDLEVEL
TEMPERATURES PROMOTING STEEPENING LAPSE RATES AND THE POTENTIAL FOR
WEAK INSTABILITY. FORCING FOR ASCENT ATTENDANT TO THIS FEATURE AND
OROGRAPHIC INFLUENCES WILL SUPPORT ISOLATED TSTM DEVELOPMENT FROM
THIS AFTERNOON THROUGH THIS EVENING.

ELSEWHERE...ISOLATED TSTMS WILL BE POSSIBLE THIS AFTERNOON AND
EVENING INVOF OF A LEE LOW DEVELOPING ALONG THE RATON MESA WHERE
STEEP LOW TO MIDLEVEL LAPSE RATES WILL PROMOTE A WEAKLY UNSTABLE
ENVIRONMENT.

..MEAD/JIRAK.. 04/06/2013

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