SWODY3
SPC AC 190729
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT SAT MAR 19 2011
VALID 211200Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS LATE MON AFTN AND EVE ACROSS
PARTS OF WRN/CNTRL KANSAS INTO S CNTRL NEBRASKA...
...SYNOPSIS...
THE SPREAD AMONG THE MODEL ENSEMBLES BEGINS TO INCREASE DURING THIS
FORECAST PERIOD CONCERNING DEVELOPMENTS WITHIN AN EVOLVING BLOCKING
PATTERN OVER NORTH AMERICA. BUT GUIDANCE CONTINUES TO SUGGEST THAT
A SIGNIFICANT UPPER TROUGH...MIGRATING INLAND ACROSS THE CALIFORNIA
COAST SUNDAY NIGHT...WILL GRADUALLY LIFT NORTHEASTWARD ACROSS THE
INTERMOUNTAIN WEST MONDAY AND MONDAY NIGHT. SIGNIFICANT MID-LEVEL
HEIGHT FALLS WILL PROBABLY NOT REACH THE HIGH PLAINS UNTIL AT LEAST
LATE MONDAY EVENING. UNTIL THEN...AN UPPER RIDGE WILL REMAIN
PROMINENT THROUGH MUCH OF THE PLAINS...EXTENDING NORTH OF A STRONG
MID-LEVEL HIGH CENTER NEAR THE MEXICAN GULF COAST. DOWNSTREAM...AN
INITIAL SHORT WAVE IMPULSE EMANATING FROM THE LARGER-SCALE WESTERN
TROUGH...AND ANOTHER STRONGER IMPULSE DIGGING SOUTHEAST OF HUDSON
BAY...APPEAR LIKELY TO SUPPRESS THE NORTHEASTERN PERIPHERY OF THE
RIDGE... ACROSS PARTS OF THE OHIO VALLEY AND CENTRAL APPALACHIANS.
IN LOWER LEVELS...A COLD FRONT IS EXPECTED TO ADVANCE SOUTHEAST OF
THE LOWER GREAT LAKES...WHILE IT STALLS AND BEGINS TO RETREAT ACROSS
PARTS OF THE CENTRAL PLAINS AND MIDDLE MISSISSIPPI VALLEY ...AHEAD
OF DEEPENING SURFACE CYCLONE ACROSS THE NORTH CENTRAL PLAINS BY LATE
MONDAY NIGHT. DESPITE CONSIDERABLE STRENGTHENING OF A SOUTHERLY
LOW-LEVEL JET /IN EXCESS OF 50 KT ACROSS PARTS OF CENTRAL KANSAS BY
LATE MONDAY EVENING/...RIDGING ACROSS THE GULF COAST IS EXPECTED TO
CONTINUE TO IMPEDE GULF MOISTURE RETURN. SUBSTANTIVE BOUNDARY LAYER
MOISTURE CHARACTERIZED BY LOWER 60S SURFACE DEW POINTS MAY BE
CONFINED TO A CORRIDOR ALONG THE FRONTAL ZONE NEAR THE MID MISSOURI
VALLEY...PERHAPS NEAR THE DRY LINE ACROSS WEST CENTRAL KANSAS INTO
SOUTH CENTRAL NEBRASKA DURING THE LATE AFTERNOON AND EVENING.
...CENTRAL PLAINS...
MID-LEVEL INHIBITION APPEARS LIKELY TO REMAIN STRONG THROUGH MUCH OF
THE DAYTIME HOURS...SUPPRESSING CONVECTIVE DEVELOPMENT WITHIN A
DESTABILIZING BOUNDARY LAYER ALONG THE DRY LINE...FROM THE FRONTAL
INTERSECTION SOUTHWARD THROUGH THE HIGH PLAINS. ALTHOUGH STRONGER
MID-LEVEL FORCING MAY NOT REACH THE REGION UNTIL MUCH LATER MONDAY
NIGHT...INCREASINGLY DIFLUENT UPPER FLOW COUPLED WITH LOCALIZED
WEAKENING OF INHIBITION SEEMS TO OFFER SLIGHTLY BETTER POTENTIAL FOR
STORM DEVELOPMENT THAN SUNDAY. THIS SEEMS MOST LIKELY TO OCCUR
WHERE DRY LINE CONVERGENCE BECOMES ENHANCED ...ALONG AND NORTH OF A
BROADLY CYCLONIC 500 MB JET AXIS ACROSS SOUTHWEST KANSAS...THOUGH
PERHAPS NOT UNTIL AROUND 00Z OR SHORTLY THEREAFTER. ONCE STORMS
FORM...THE ENVIRONMENT WILL BE CONDUCIVE FOR SUPERCELLS THAT MAY
PERSIST THROUGH THE EVENING BEFORE WEAKENING WITH BOUNDARY LAYER
STABILIZATION. ONCE THIS OCCURS... MAIN CONVECTIVE DEVELOPMENT IS
EXPECTED TO SHIFT TO A STRENGTHENING WARM ADVECTION REGIME NORTH OF
THE SURFACE FRONT... NEAR/NORTHEAST OF THE MID MISSOURI VALLEY.
...OHIO VALLEY INTO CENTRAL APPALACHIANS...
MODERATELY STRONG CLOUD BEARING LAYER MEAN FLOW ON THE ORDER OF 40+
KT COUPLED WITH WEAK BOUNDARY LAYER DESTABILIZATION COULD SUPPORT
RISK FOR STORMS WITH POTENTIAL FOR DAMAGING WINDS ALONG AND SOUTH OF
THE SURFACE FRONT MONDAY AFTERNOON.
..KERR.. 03/19/2011
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