[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 110558
SWODY1
SPC AC 110556

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT MON SEP 11 2006

VALID 111200Z - 121200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
POSITIVELY TILTED BROAD MID/UPPER LEVEL TROUGH...CURRENTLY EXTENDING
FROM THE UPPER MS VALLEY TO THE SRN HIGH PLAINS PER WATER VAPOR
IMAGERY...WILL MOVE SLOWLY EWD ACROSS THE CENTRAL U.S. TODAY. 
MEANWHILE...A SHORT WAVE TROUGH...NOW MOVING SSEWD INTO ERN
MT...WILL CONTINUE TO DIG SWD FROM THE NRN INTO CENTRAL HIGH PLAINS
ALONG WRN PERIPHERY OF CENTRAL U.S. LARGE SCALE TROUGH.

AT THE SURFACE...PRIMARY LOW OVER THE CENTRAL U.S. SHOULD BE LOCATED
OVER NRN MO AT 12Z THIS MORNING...AND THEN MOVE NEWD REACHING SRN
LAKE MICHIGAN REGION BY 12Z TUESDAY.  TRAILING COLD FRONT WILL
SPREAD E AND SE ACROSS THE MID MS VALLEY AND SRN PLAINS...AND SHOULD
EXTEND FROM THE SURFACE LOW SSWWD THROUGH ERN AR TO SOUTH CENTRAL TX
BY END OF THE PERIOD.

...N TX/PART OF LOWER MS VALLEY TO MID MS/LOWER OH VALLEYS...
AT 12Z TODAY...AN AREA OF PRECIPITATION WITH EMBEDDED THUNDERSTORMS
SHOULD BE ONGOING FROM PART OF THE OZARKS REGION NEWD TO THE
MIDWEST.  CLOUD COVER ASSOCIATED WITH THIS ACTIVITY MAY LIMIT
SURFACE HEATING AND DESTABILIZATION ACROSS THE LOWER OH AND MID MS
VALLEYS.  AIR MASS IN ADVANCE OF THE COLD FRONT IS EXPECTED TO
REMAIN MOIST...BUT WEAK LAPSE RATES AND/OR LIMITED SURFACE HEATING
SHOULD RESULT IN GENERALLY MODEST INSTABILITY /MLCAPE AROUND 1000
J/KG/. 

ASCENT WITH ANY WEAK MID LEVEL IMPULSE MOVING ACROSS THIS REGION
TODAY WILL PROVE FAVORABLE IN AIDING THUNDERSTORM DEVELOPMENT WITHIN
A WEAKLY CAPPED AIR MASS.  EFFECTIVE BULK SHEAR VALUES WILL BE
MODEST /20-25 KT/...SUGGESTING MULTICELLS/CLUSTERS WILL BE
POSSIBLE...BUT OVERALL WEAK FORCING AND INSTABILITY SHOULD LIMIT THE
SEVERE THREAT. STORMS THAT CAN MAINTAIN UPDRAFT STRENGTH WILL HAVE
THE POTENTIAL TO PRODUCE ISOLATED HAIL AND/OR STRONG WIND GUSTS. 
THREAT SHOULD DIMINISH THIS EVENING AS THE BOUNDARY STABILIZES WITH
THE LOSS OF DAYTIME HEATING.

...ERN CO/ERN NM...
DESPITE STEEP MID LEVEL LAPSE RATES EXPECTED FROM CO INTO NERN
NM...LIMITED LOW LEVEL MOISTURE WITH NWD EXTENT ACROSS THIS REGION
SHOULD RESULT IN MLCAPE VALUES AOB 500 J/KG.  LARGE SCALE ASCENT
AHEAD OF THE SWD MOVING SHORT WAVE TROUGH SHOULD PROVIDE SUFFICIENT
DESTABILIZATION FOR AN ISOLATED HAIL/STRONG WIND GUST POTENTIAL
ACROSS ERN CO. FARTHER S...UPSLOPE FLOW INTO PARTS OF ERN NM AND
STRONG SURFACE HEATING SHOULD SUPPORT ISOLATED THUNDERSTORM
DEVELOPMENT.  EFFECTIVE BULK SHEAR VALUES OVER THE CENTRAL/SRN HIGH
PLAINS WILL BE SUFFICIENT FOR ORGANIZED STORMS...BUT WEAK
INSTABILITY SHOULD LIMIT THE SEVERE COVERAGE.  THUS...THE REASON FOR
MAINTAINING LOW SEVERE HAIL/WIND PROBABILITIES.

..PETERS/GUYER.. 09/11/2006