[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 131233
SWODY1
SPC AC 131231

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0731 AM CDT THU JUL 13 2006

VALID 131300Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF PLAINS STATES SWD
TO OK...

...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF THE MID ATLANTIC
STATES...

...SYNOPSIS...
ENERGY WITH TROUGH NOW ENTERING THE NORTHERN HIGH PLAINS WILL SPLIT
AS UPPER HIGH BUILDS NWD THRU INTERIOR WRN U.S.  MAIN PORTION OF
TROUGH CONTINUES EWD TO UPPER MS VALLEY BY LATE TONIGHT WITH A SRN
PORTION HEADING SEWD DOWN THE MO RIVER VALLEY...REACHING MO BY 12Z
FRI.

A PERSISTENT SLY LOW LEVEL JET OF 20-30 KT CONTINUES TO FEED VERY
MOIST AIR NWD THRU THE CENTRAL PLAINS IN ADVANCE OF THE COLD FRONT
CURRENTLY LOCATED FROM CENTRAL ND SSWWD TO NEB PANHANDLE.

BY MID-AFTERNOON THE COMBINATION OF STRONG HEATING WITH SFC
TEMPERATURES TO NEAR 100F NWD INTO NEB AHEAD OF FRONT AND DEWPOINTS
WELL INTO THE 60S WILL RESULT IN A VERY TO EXTREMELY UNSTABLE AIR
MASS WITH MLCAPES POSSIBLY AOA 4000 J/KG.

THE DIRECTIONAL SHEAR WITH LOW LEVEL SLYS AND 20-30KT NWLY MID LEVEL
FLOW ACCOMPANYING THE S/WV TROUGH DROPPING SEWD THRU PLAINS...WILL
PROVIDE 30-35KT OF DEEP LAYER SHEAR BY MID AFTERNOON. THIS IS MORE
THAN SUFFICIENT TO SUPPORT SUPERCELL DEVELOPMENT GIVEN THE AVAILABLE
INSTABILITY.

BOTH THE NAM AND GFS HAVE A PARTICULARLY STRONG CONVECTIVE SIGNAL ON
THE 06Z RUNS BY LATE THIS AFTERNOON OVER ERN NE AND THIS SEEMS
REASONABLE GIVEN THE SYNOPTIC CONDITIONS.

CAP WILL ERODE SUFFICIENTLY TO ALLOW RAPID INITIATION OF SURFACE
BASED THUNDERSTORMS VICINITY FRONTAL ZONE BY LATE AFTERNOON.  IN THE
EARLY STAGES OF DEVELOPMENT VERY LARGE HAIL IS LIKELY WITH THE
MODELS INDICATING RAPID DEVELOPMENT OF A COLD POOL GIVEN THE LARGE
DCAPES UPWARDS TO 1500 J/KG OR GREATER IN THE WARM SECTOR.  DAMAGING
WINDS WILL THEN BE PRIMARY CONCERN AS A POTENTIAL SEVERE MCS
PROPAGATES SEWD ACROSS ERN NEB INTO NRN KS AND NWRN MO.

WILL RAISE PROBABILITIES OF BOTH WIND AND HAIL HOWEVER WITHHOLD A
CATEGORY UPGRADE UNTIL NEXT MODEL RUN LENDS MORE CONFIDENCE IN THE
INDICATED SCENARIO OF 06Z SOLUTIONS.

SUFFICIENT INSTABILITY AND SHEAR AHEAD OF FRONT NWD TO THE CANADIAN
BORDER FOR POTENTIAL SUPERCELLS AND DAMAGING WIND AND HAIL THREAT BY
MID AFTERNOON.

...MID ATLANTIC STATES...
E/W COLD FRONT ACROSS PA SLOWLY DROPPING SWD PRECEEDED BY A DEEP
LAYER OF VERY MOIST AIR WITH PW/S IN EXCESS OF 2 INCHES.  SEVERE
THREAT IN THE E TODAY WILL MOST LIKELY OCCUR NEAR THE INTERFACE OF
THE THICKER CLOUD COVER AND STRONG HEATING S OF FRONT OVER
CENTRAL/SRN VA INTO NRN NC.  WHILE MLCAPES IN THIS AREA WILL CLIMB
TO 2000 J/KG OR MORE...THE WEAK LAPSE RATES AND MARGINAL SHEAR
SHOULD CONFINE ANY SEVERE THREAT TO DAMAGING WINDS.  THE 20-25KT OF
SHEAR SUPPORT MULTICELL AND POSSIBLY LINE SEGMENTS DEVELOPING BY MID
AFTERNOON WITH ASSOCIATED POTENTIAL WET MICRO BURSTS.

...MID MISSISSIPPI AND TN VALLEYS...
VERY MOIST AND UNSTABLE AIR WILL PREVAIL S OF STATIONARY FRONTAL
ZONE FROM THE MID MS VALLEY EWD TO APPALACHIANS.  WEAK SHEAR
PROFILES WILL BE CONDUCIVE TO PRIMARILY A PULSE SEVERE THREAT. THUS
WHILE THERE IS THE POTENTIAL FOR DAMAGING DOWNBURSTS AND LARGE HAIL
OVER MUCH OF THIS AREA...COVERAGE WILL BE LIMITED PRECLUDING TRYING
TO IDENTIFY A RISK AREA ATTM.

..HALES/GRAMS.. 07/13/2006