[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 151307
SWODY1
SPC AC 151305

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0805 AM CDT SAT APR 15 2006

VALID 151300Z - 161200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE MID/LWR MO
VLYS...

...THERE IS A SLGT RISK OF SVR TSTMS FROM NEB/NRN KS TO THE MID MS
VLY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM OH TO THE MID ATLANTIC
CST...

...SYNOPSIS...
STRONG UPR IMPULSE NOW OVER CO/NRN NM SHOULD CONTINUE RAPIDLY NE
INTO CNTRL NEB BY THIS EVENING...BEFORE DECELERATING AS IT CLOSES
OFF OVER IA EARLY SUNDAY.  ASSOCIATED LEE LOW NOW OVER NE CO
EXPECTED TO TRACK TO NEAR KOFU BY EARLY TONIGHT AS TRAILING PACIFIC
COLD FRONT SWEEPS INTO FAR ERN KS.

DEEPENING OF NEB LOW SHOULD DRAW BOUNDARY NOW EXTENDING FROM NRN KS
INTO CNTRL MO/SRN IL NWD AS A WARM FRONT.  AT THE SAME TIME...EXPECT
THAT ERN PART OF SAME BOUNDARY WILL DROP S ACROSS THE MID ATLANTIC
STATES IN RESPONSE TO GRADUAL INCREASE IN NWLY MID/UPR LEVEL FLOW
DOWNSTREAM FROM AMPLIFYING SYSTEM IN THE PLAINS.

...MID/LWR MO VLY...
CONDITIONS EXPECTED TO BECOME FAVORABLE FOR SEVERE STORMS OVER A
SMALL PART OF THE CNTRL PLNS/LWR MO VLY LATE THIS AFTERNOON INTO
TONIGHT AS ABRUPT INCREASE IN ASCENT ASSOCIATED WITH APPROACHING UPR
TROUGH OVERSPREADS REGION.  COMBINATION OF SURFACE HEATING AND
CONVERGENCE ALONG AND AHEAD OF COLD FRONT SHOULD OVERCOME CIN AND
SUPPORT STORM DEVELOPMENT BY MIDDAY...MOST LIKELY OVER WRN/CNTRL
NEB.  DEVELOPMENT SHOULD THEN SPREAD S INTO NRN/NE KS WITH TIME AS
HEATING FURTHER DESTABILIZES LWR LAYERS...AND FORCING FOR ASCENT
ENCOUNTERS MORE SUBSTANTIAL LOW LEVEL MOISTURE INFLOW.

COMPACT NATURE OF EJECTING TROUGH AND ASSOCIATED LATITUDINAL
VARIATION OF WIND FIELD WILL RESULT IN A HIGHLY VARIABLE DEEP SHEAR
PATTERN WITH SPACE/TIME ACROSS THE CNTRL PLNS/LWR MO VLY.  SUFFICE
IT TO SAY THAT SHEAR WILL NEVERTHELESS BE SUFFICIENT FOR ORGANIZED
STORMS/SUPERCELLS THROUGH THE REGION DURING PERIOD OF EXPECTED
CONVECTIVE DEVELOPMENT.  BUT TEMPORAL VARIATION OF WIND PROFILES...
AND THE RELATIVELY LIMITED MOISTURE SUPPLY AT THE OUTSET...DO
SERIOUSLY COMPLICATE FORECAST OF DOMINATE CONVECTIVE MODE.

WITH INITIAL LOW TO MID LEVEL ENVIRONMENT EXPECTED TO REMAIN LARGELY
UNSATURATED OVER MUCH OF ERN NEB...AND PROSPECTS FOR SUBSTANTIAL LOW
LEVEL MOISTENING BETWEEN NOW AND CONVECTIVE INITIATION TIME LOOKING
SLIM...EXPECT THAT MAIN SEVERE THREATS WILL BE HIGH WIND AND HAIL
FROM ROTATING STORMS ORGANIZED IN SHORT BANDS/CLUSTERS.  FARTHER S
AND E...POTENTIAL FOR LONG-LIVED/MORE DISCRETE SUPERCELLS APPEARS
SOMEWHAT GREATER INVOF WARM FRONT IN EXTREME ERN NEB/WRN IA AND NRN
MO.  ENHANCED LOW LEVEL SRH COULD YIELD A TORNADO THREAT IN ADDITION
TO LARGE HAIL/HIGH WIND.

...MID MS VLY...
FARTHER E...OTHER SEVERE TSTMS MAY DEVELOP DURING AFTERNOON/EVENING
INVOF WARM FRONT OVER PARTS OF THE MID MS VLY. VERTICAL
SHEAR...WHILE NOT AS INTENSE AS NEAR UPR TROUGH...MAY -- STILL
SUPPORT SEVERE MULTICELLS AND PERHAPS MARGINAL SUPERCELLS.
WEAK LOW LEVEL WINDS SHOULD KEEP SRH RELATIVELY SMALL AND MID/UPR
LEVEL FORCING LIKELY WILL REMAIN WEAK. BUT HEATING COULD BOOST
MLCAPE TO 2000-2500 J/KG.      SUPERCELL POTENTIAL MAY INCREASE
AFTER DARK OVER ERN MO/IL AS STRONGER FLOW ALOFT OVERSPREADS AREA
AHEAD OF UPR TROUGH.

...OH TO MID ATL CST/TIDEWATER AREA...
MODERATE...SLIGHTLY DIFFLUENT...DEEP WNW TO NWLY FLOW WILL PREVAIL
FROM THE UPR OH VLY TO THE MID ATLANTIC COAST THROUGH THE PERIOD. 
SATELLITE SUGGESTS A WEAK IMPULSE NOW CRESTING THE WV MOUNTAINS...
WITH A SIMILAR DISTURBANCE UPSTREAM OVER WRN LWR MI.  SURFACE
FEATURES ARE DIFFUSE OVER THE REGION...WITH ONE BOUNDARY EXTENDING
FROM SW OH TO CNTRL NY...AND ANOTHER OF APPARENT CONVECTIVE ORIGIN
EXTENDING FROM SRN OH TO TIDEWATER VIRGINIA.  WHILE MID LEVEL LAPSE
RATES ARE NOT PARTICULARLY STEEP...THEY ARE SUFFICIENT FOR
STORMS...ESPECIALLY GIVEN THAT SURFACE HEATING SHOULD BE FAIRLY
STRONG FROM CNTRL/SRN OH ESE TO THE MID ATLANTIC COAST.  OVERALL
PATTERN SUGGESTS THE LIKELIHOOD FOR THE DEVELOPMENT OF SCATTERED
BANDS/SMALL CLUSTERS OF MAINLY DIURNAL STORMS THAT WILL HAVE THE
POTENTIAL FOR HAIL AND POSSIBLY LOCALLY DAMAGING WIND.

..CORFIDI/GRAMS.. 04/15/2006