[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 252002
SWODY1
SPC AC 252000

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT FRI AUG 25 2006

VALID 252000Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE CNTRL/SRN
HIGH PLAINS TO GREAT LAKES/NRN OH VALLEY...AND THEN SEWD TO THE MID
ATLANTIC COAST...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ERN UT...NWRN CO
AND SWRN WY...

...UPPER MIDWEST/SRN GREAT LAKES TO MID ATLANTIC COAST...

LATEST MESOANALYSIS INDICATED A SURFACE LOW OVER NERN IA/SWRN WI
WITH AN ATTENDANT WARM OR QUASI-STATIONARY BOUNDARY EXTENDING EWD
THROUGH CNTRL LOWER MI AND THEN MORE ESEWD FROM NEAR BUF TO CNTRL
NJ.  A COLD FRONT THEN STRETCHED SWWD FROM THIS LOW THROUGH S-CNTRL
IA.  BREAKS IN THE CLOUDS FROM SERN WI/NRN IL INTO ERN IA HAVE
ALLOWED BOUNDARY LAYER TO WARM TO 75-85 F AND WHEN COUPLED WITH DEW
POINTS IN THE UPPER 60S TO LOWER 70S...AIR MASS HAS BECOME
MODERATELY UNSTABLE WITH MLCAPES OF 1000-2000 J/KG.

CONVERGENCE ALONG THESE BOUNDARIES IN CONJUNCTION WITH INFLUENCE OF
WEAKENING SHORT WAVE TROUGH OVER NRN/CNTRL WI INTO NRN LOWER MI HAVE
CONTRIBUTED TO INCREASING STORM COVERAGE AND INTENSITY OVER SRN
WI/NRN IL.  LOCAL VADS INDICATE MODEST VERTICAL SHEAR OF 30-35 KTS
WHICH IS SUFFICIENT TO SUPPORT ORGANIZED UPDRAFTS GIVEN THE MODERATE
INSTABILITY.  SEVERE HAIL AND LOCALLY DAMAGING WINDS WILL BE THE
PRIMARY SEVERE WEATHER THREATS WITH THESE STORMS.

FOR ADDITIONAL SHORT TERM GUIDANCE...PLEASE SEE MCD 1883.

ADDITIONAL STORMS WILL BE POSSIBLE FARTHER TO THE E OVER CNTRL/SRN
LOWER MI...EVENTUALLY INTO THE UPPER OH VALLEY LATER THIS AFTERNOON
INTO TONIGHT AS AFOREMENTIONED SHORT WAVE TROUGH CONTINUES EWD. 
CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS HAS LIMITED AIR MASS
DESTABILIZATION THUS FAR TODAY...AND THIS MAY CONTINUE TO BE A
FACTOR WHICH LIMITS OVERALL SEVERE THREAT.  HOWEVER...SHOULD STORMS
DEVELOP AND BECOME SUSTAINED...SUFFICIENT VERTICAL SHEAR WILL EXIST
FOR A FEW SEVERE STORMS CAPABLE OF HIGH WINDS AND SOME HAIL.

FARTHER SE OVER ERN PA/NJ...REGION APPEARS TO BE IN SOME DEGREE OF
LARGE SCALE SUBSIDENCE IN WAKE OF SHORT WAVE TROUGH WHICH PASSED
THROUGH EARLIER TODAY. ABUNDANT SUNSHINE MAY STILL ALLOW FOR THE
RE-DEVELOPMENT OF STORMS LATE THIS AFTERNOON OR EVENING ALONG
PRE-EXISTING LOW-LEVEL BOUNDARY.  SHOULD STORMS DEVELOP...DEEP NWLY
FLOW WILL SUPPORT SOME DAMAGING WIND POTENTIAL WITH THE MORE
ORGANIZED CELLS.

...CNTRL/SRN HIGH PLAINS TO LOWER MO VALLEY...

TRAILING PORTION OF COLD FRONT EXTENDED SWWD THROUGH NWRN MO TO
SECONDARY LOW PRESSURE OVER S-CNTRL KS AND WSWWD INTO NERN NM AS OF
19Z.  RELATIVELY CLOUD FREE SKIES S OF THIS BOUNDARY HAVE ALLOWED
FOR STRONG DIABATIC HEATING WITHIN MOIST BOUNDARY LAYER WHERE
MLCAPES HAVE INCREASED TO 2000-3000 J/KG WITH A RAPIDLY WEAKENING
CAP.  THIS DESTABILIZATION COUPLED WITH INCREASED FORCING FOR ASCENT
ASSOCIATED WITH SHORT WAVE TROUGH SHIFTING EWD OUT OF ERN CO SHOULD
SUPPORT AN INCREASE IN TSTM COVERAGE ALONG FRONT LATE THIS AFTERNOON
INTO EVENING.

PROFILER/VAD OBSERVATIONS INDICATE VERTICAL SHEAR SUPPORTIVE OF
SUPERCELLS OVER SERN CO/SWRN KS...WITH A GENERAL DECREASE WITH NEWD
EXTENT ACROSS KS INTO MO.  THE STRONGEST STORMS WILL BE CAPABLE OF
LARGE HAIL GIVEN THE STEEP MID-LEVEL LAPSE RATES AND ROTATIONAL
UPDRAFT POTENTIAL...AS WELL AS LOCALLY DAMAGING WIND GUSTS.  THE
SEVERE THREAT SHOULD DIMINISH BY LATE EVENING AS BOUNDARY LAYER
COOLS AND STABILIZES.

...UT/SRN WY/WRN CO...

VISIBLE SATELLITE IMAGERY AND RADAR DATA INDICATE TSTMS DEVELOPING
ALONG THE ERN SLOPES OF THE WASATCH THIS AFTERNOON IN RESPONSE TO
APPROACH OF SHORT WAVE TROUGH THROUGH ERN NV INTO WRN UT.  WHILE
BOUNDARY LAYER IS NOT PARTICULARLY WARM OR MOIST...THE PRESENCE OF
STEEP LOW TO MID LEVEL LAPSE RATES ARE CONTRIBUTING TO MODERATE
INSTABILITY WITH MLCAPES OF 500-1500 J/KG.  INCREASING MID AND
HIGH-LEVEL WIND FIELDS IN ASSOCIATION WITH APPROACHING IMPULSE ARE
RESULTING IN SUFFICIENT VERTICAL SHEAR FOR SOME STORM
ORGANIZATION/ROTATION. ISOLATED SEVERE HAIL AND LOCALLY DAMAGING
WINDS WILL BE THE GREATEST THREATS WITH THESE MORE INTENSE STORMS.

..MEAD.. 08/25/2006