[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 050530
SWODY1
SPC AC 050529

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1229 AM CDT TUE SEP 05 2006

VALID 051200Z - 061200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

MID/UPPER-LEVEL LOW OVER NRN IL/SRN WI IS FORECAST TO EVOLVE INTO A
POSITIVELY TITLED OPEN WAVE FROM THE OH VALLEY INTO THE CNTRL GULF
STATES WITH STRONGEST HEIGHT FALLS SHIFTING EWD INTO THE
APPALACHIANS.  IN THE LOW-LEVELS...PRIMARY BAROCLINIC ZONE INITIALLY
SITUATED ALONG THE CNTRL/SRN APPALACHIANS WILL SHIFT EWD TODAY
THROUGH THE PIEDMONT INTO THE COASTAL PLAIN WITH SEVERAL WEAK WAVES
DEVELOPING NEWD ALONG THIS BOUNDARY.

...OH VALLEY...

CORE OF UPPER LOW HAS SLOWLY MODIFIED OVER THE PAST COUPLE OF
DAYS...RESULTING IN PROGRESSIVELY WEAKER INSTABILITY. 
STILL...MID-LEVEL TEMPERATURES ARE EXPECTED TO REMAIN BETWEEN -14
AND -16 C AT 500 MB...AND WHEN COUPLED WITH DAYTIME HEATING...AIR
MASS WILL BECOME WEAKLY UNSTABLE WITH SBCAPES OF AROUND 500 J/KG. 
TSTMS WILL BECOME INCREASINGLY WIDESPREAD THIS AFTERNOON WITHIN
DESTABILIZING ENVIRONMENT FROM PORTIONS OF ERN IL EWD THROUGH IND
INTO WRN OH.  THE RELATIVELY WEAK INSTABILITY AND MARGINAL VERTICAL
SHEAR WILL LIMIT A MORE ORGANIZED SEVERE THREAT...THOUGH THE MOST
INTENSE STORMS WILL BE CAPABLE OF SOME SEVERE HAIL INTO THE EARLY
EVENING HOURS.

...CNTRL/SRN APPALACHIANS EWD TO THE ATLANTIC COAST...

LOW-LEVEL AIR MASS WILL REMAIN QUITE MOIST E OF SURFACE FRONT WITH
DEWPOINTS IN THE UPPER 60S TO LOW 70S...THOUGH WEAK LAPSE RATES
SHOULD LIMIT SBCAPES TO 1000-1500 J/KG.  INCREASING HEIGHT FALLS
AHEAD OF EVOLVING MID-LEVEL TROUGH SHOULD SUPPORT AN INCREASE IN
TSTM COVERAGE AND INTENSITY THIS AFTERNOON ACROSS THE PIEDMONT AND
COASTAL PLAIN FROM CNTRL/SRN GA NEWD INTO ERN VA.  IT APPEARS THAT
THE STRONGER MID AND HIGH-LEVEL WIND FIELDS ASSOCIATED WITH UPPER
TROUGH WILL LAG SURFACE WARM SECTOR TO THE W WITH GENERALLY 20-30
KTS OF DEEP LAYER SHEAR FORECAST ACROSS AXIS OF STRONGEST
INSTABILITY.  A FEW ORGANIZED STORMS /SOME EXHIBITING EPISODIC
MID-LEVEL ROTATION/ WILL BE POSSIBLE WITH A THREAT OF LOCALLY
DAMAGING WINDS AND PERHAPS A BRIEF TORNADO.  HOWEVER...THE MARGINAL
VERTICAL SHEAR AND WEAK LAPSE RATES SHOULD LIMIT A MORE SIGNIFICANT
SEVERE WEATHER THREAT.

...S-CNTRL/SERN CO INTO NERN NM...

LOW-LEVEL UPSLOPE REGIME IS EXPECTED TO PERSIST THROUGH THE
PERIOD...MAINTAINING MODEST LOW-LEVEL MOISTURE WITH DEWPOINTS IN THE
40S TO LOWER 50S.  WHEN COUPLED WITH DAYTIME HEATING AND STEEPENING
LAPSE RATES...ENVIRONMENT WILL BECOME WEAKLY UNSTABLE WITH SBCAPES
OF 500 J/KG.  A WEAK IMPULSE OBSERVED ON WATER VAPOR IMAGERY OVER
NRN UT WILL TURN MORE SEWD TODAY...COMBINING WITH THE SUSTAINED
LOW-LEVEL OROGRAPHIC FORCING TO INITIATE DIURNAL STORMS OVER S-CNTRL
CO.  TSTMS SHOULD THEN MOVE/DEVELOP SEWD INTO NERN NM BY THIS
EVENING.  STRONG LOW-LEVEL VEERING BENEATH 20-30 KT NNWLY MID-LEVEL
FLOW WILL RESULT IN SUFFICIENT VERTICAL SHEAR FOR UPDRAFT ROTATION. 
HOWEVER...THE MARGINAL INSTABILITY SHOULD LIMIT THE POTENTIAL FOR
MORE WIDESPREAD...ORGANIZED STORM DEVELOPMENT. STILL...A FEW OF THE
MORE INTENSE CELLS WILL BE CAPABLE OF MARGINALLY SEVERE HAIL.

..MEAD/JEWELL.. 09/05/2006