SWODY2
SPC AC 261728
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT MON MAR 26 2012
VALID 271200Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS TUE ACROSS PARTS OF THE MIDDLE
MS VALLEY INTO THE CNTRL PLAINS...
...SYNOPSIS...
MODELS INDICATE THAT A MORE CONSOLIDATED...AMPLIFIED UPPER TROUGH
WILL GRADUALLY EVOLVE OFF THE EAST COAST DURING THIS FORECAST
PERIOD...WHILE AMPLIFIED UPPER TROUGHING PERSISTS NEAR/JUST WEST OF
THE PACIFIC COAST. LARGE-SCALE RIDGING WILL PREVAIL IN
BETWEEN...ACROSS MUCH OF THE U.S...BUT A VIGOROUS EMBEDDED COMPACT
CLOSED LOW/SHORT WAVE TROUGH ARE EXPECTED TO CONTINUE GRADUALLY
PROGRESSING THROUGH ITS CREST...ACROSS THE NORTHERN PLAINS INTO THE
UPPER GREAT LAKES REGION.
A DEEP...BUT LIKELY WEAKENING...SURFACE CYCLONE WILL ACCOMPANY THIS
LATTER FEATURE...WITH AN ASSOCIATED WARM FRONT SHIFTING EAST OF THE
UPPER MISSISSIPPI VALLEY THROUGH THE GREAT LAKES AND OHIO VALLEY
REGION...WHILE A TRAILING COLD FRONT ADVANCES SOUTHEAST OF THE NORTH
CENTRAL CANADIAN/U.S. BORDER AREA...BEFORE STALLING ACROSS THE LOWER
MISSOURI VALLEY AND CENTRAL PLAINS. IN THE WAKE OF THE UPPER CLOSED
LOW/TROUGH NOW FINALLY SHIFTING EAST OF SOUTH ATLANTIC COASTAL
AREAS...WARM SECTOR MOISTENING APPEARS LIKELY TO REMAIN SOMEWHAT
LIMITED...AND LARGELY CONFINED TO A NARROW CORRIDOR ALONG A
CONFLUENCE ZONE ASSOCIATED WITH THE MAIN PRE-FRONTAL SOUTHERLY
LOW-LEVEL JET. STILL...DESTABILIZATION IS EXPECTED TO BE SUFFICIENT
TO SUPPORT AT LEAST SCATTERED THUNDERSTORM ACTIVITY ACROSS PARTS OF
THE MIDDLE MISSISSIPPI VALLEY AND GREAT LAKES REGION INTO THE OHIO
VALLEY...WITH ADDITIONAL THUNDERSTORMS POSSIBLE NEAR THE DRY LINE
ACROSS THE SOUTHERN PLAINS...AND WITHIN A STRENGTHENING LOWER/MID
TROPOSPHERIC WARM ADVECTION REGIME ACROSS THE CENTRAL PLAINS BY LATE
TUESDAY NIGHT. AND THE RISK FOR AT LEAST MARGINAL SEVERE HAIL/WIND
GUSTS MAY NOT BE COMPLETELY NEGLIGIBLE IN MOST AREAS.
...PLAINS/MS VALLEY INTO GREAT LAKES REGION...
THE STRONGEST MID/UPPER FORCING FOR UPWARD VERTICAL MOTION APPEARS
LIKELY TO SPREAD INTO AREAS NEAR/NORTH OF THE CANADIAN/U.S. BORDER
IN ADVANCE OF THE BETTER LOW-LEVEL MOISTURE RETURN. THIS IS
EXPECTED...IN GENERAL...TO LIMIT THE OVERALL SEVERE WEATHER THREAT
FOR THIS PERIOD. HOWEVER...MODELS ARE SUGGESTIVE THAT COOLING
ASSOCIATED WITH UPPER LOW MAY WEAKEN INHIBITION SUFFICIENTLY TO
SUPPORT INCREASING THUNDERSTORM ACTIVITY AS IT OVERSPREADS THE
PRE-FRONTAL LOW-LEVEL MOIST AXIS ...ACROSS PARTS OF EASTERN KANSAS
AND NORTHWEST MISSOURI INTO EASTERN IOWA AND WESTERN WISCONSIN.
LOWER/MID TROPOSPHERIC WARM ADVECTION MAY SUPPORT ADDITIONAL STORM
DEVELOPMENT JUST AHEAD OF THE SOUTHERN FLANK OF THIS NARROW BROKEN
CONVECTIVE BAND...ACROSS PARTS OF NORTHERN INTO WEST CENTRAL
MISSOURI...WHICH SHOULD BE MOSTLY BASED ABOVE THE BOUNDARY
LAYER...WITH LIMITED SEVERE POTENTIAL...AS IT SPREADS EAST
SOUTHEASTWARD BEFORE DIMINISHING DURING THE AFTERNOON.
IN THE WAKE OF THIS INITIAL ACTIVITY...MODERATE BOUNDARY LAYER
DESTABILIZATION /CAPE OF 1000-2000 J PER KG/ IS EXPECTED BENEATH
STEEP LAPSE RATES...ALONG AN AXIS FROM SOUTHEASTERN KANSAS INTO
NORTHWESTERN ILLINOIS. VERTICAL SHEAR IS EXPECTED TO REMAIN AT
LEAST MODESTLY STRONG ALONG THIS AXIS...EVEN WITH THE STRONGER LOW
AND MID-LEVEL JET CORES SHIFTING THROUGH THE UPPER MISSISSIPPI
VALLEY AND GREAT LAKES REGION. WHILE FORCING FOR LARGE-SCALE ASCENT
IS EXPECTED TO WEAKEN AT THE SAME TIME... MID-LEVEL INHIBITION
SHOULD REMAIN WEAK ENOUGH FOR SCATTERED STRONG/SEVERE STORM
DEVELOPMENT LATE TUESDAY AFTERNOON. THIS MAY INCLUDE A FEW
SUPERCELLS...PARTICULARLY ACROSS PARTS OF NORTHEAST MISSOURI INTO
NORTHWEST/WEST CENTRAL ILLINOIS...BEFORE CONVECTION
WEAKENS/DIMINISHES DURING THE EVENING HOURS.
..KERR.. 03/26/2012
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