DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 120558
SWODY1
SPC AC 120556

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT MON APR 12 2010

VALID 121200Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN ND ESEWD INTO NERN
SD...

...SYNOPSIS...
LARGE-SCALE UPPER TROUGH/LOW WILL MOVE EWD ACROSS THE WRN U.S.
THROUGH THE FIRST HALF OF THE PERIOD...BUT SHOULD BEGIN TO BE
SHUNTED NEWD ACROSS THE CENTRAL ROCKIES AS IT IMPINGES ON AN
AMPLIFYING RIDGE OVER THE CENTRAL CONUS.

AT THE SURFACE...A BROAD AREA OF LOW PRESSURE INTIALLY ACROSS THE
GREAT BASIN/ROCKIES SHOULD BEGIN TO CONSOLIDATE OVER THE NRN HIGH
PLAINS REGION BY AFTERNOON...WITH A W-E FRONT EXPECTED TO STRETCH
FROM SD EWD ACROSS THE NRN IA/SRN MN VICINITY INTO NRN IL/SRN WI
THROUGH MOST OF THE PERIOD. WIDESPREAD SHOWERS AND THUNDERSTORMS
ARE FORECAST -- PARTICULARLY DURING THE SECOND HALF OF THE PERIOD --
NEAR AND N OF THIS FRONT. ELSEWHERE...SCATTERED SHOWERS AND
THUNDERSTORMS WILL AFFECT MUCH OF THE WESTERN U.S. IN CONJUNCTION
WITH THE PASSAGE OF THE UPPER TROUGH...WHILE MOST OF THE EAST
REMAINS DRY.

...PORTIONS OF ND INTO NERN SD...
LARGE-SCALE SUBSIDENCE ASSOCIATED WITH INCREASING UPPER
RIDGING/HEIGHT RISES OVER THE PLAINS STATES WILL MAINTAIN A CAPPING
INVERSION ACROSS MUCH OF THE CENTRAL U.S. WARM SECTOR THIS PERIOD.
WHILE AN ISOLATED AFTERNOON STORM OR TWO MAY DEVELOP OVER THE
CENTRAL PLAINS AND WEAKER SHOWERS/ISOLATED STORMS MAY DEVELOP NEAR
THE CO FRONT RANGE AND ADJACENT HIGH PLAINS...ANY SEVERE THREAT
APPEARS LIMITED ENOUGH ATTM TO PRECLUDE THE INTRODUCTION OF ANY
SEVERE PROBABILITIES.

FARTHER N...PERSISTENT WARM ADVECTION/ISENTROPIC LIFT ATOP THE W-E
SURFACE FRONT INVOF ND SHOULD YIELD MOISTENING/DESTABILIZATION ABOVE
A STABLE BOUNDARY LAYER. AS THE LOW-LEVEL JET INCREASES OVERNIGHT
TO IN EXCESS OF 60 KT OVER THIS REGION...EXPECT CONVECTION TO
UNDERGO A SIGNIFICANT NOCTURNAL INCREASE. WITH STEEP LAPSE RATES
EXPECTED ACROSS THE REGION AND DEEP-LAYER SHEAR LIKELY SUFFICIENT
FOR AT LEAST SEMI-ORGANIZED STORMS...HAIL WILL BE POSSIBLE WITH
STRONGER STORMS. CONVECTION WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH AT LEAST SOME HAIL POTENTIAL LIKELY TO LINGER THROUGH
THE END OF THE PERIOD.

..GOSS/STOPPKOTTE.. 04/12/2010

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