[SWODY2] SWODY2

Sat Aug 5 06:08:08 UTC 2006

ACUS02 KWNS 050604
SWODY2
SPC AC 050603

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0103 AM CDT SAT AUG 05 2006

VALID 061200Z - 071200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
SYNOPTIC UPPER AIR PATTERN SHOULD FEATURE SLOW NEWD EJECTION OF
PRESENTLY CUT-OFF PACIFIC LOW ACROSS NRN CA/ORE...PROGRESSIVE NRN
STREAM BELT ACROSS NRN 1/4 OF CONUS...AND WWD EXTENSION OF BERMUDA
RIDGE ACROSS SERN/S-CENTRAL STATES.  SRN CONUS RIDGE MAY BE
REGIONALLY INTRUDED BY WEAK AND SLOW-MOVING PERTURBATIONS -- PERHAPS
CONVECTIVELY GENERATED/ENHANCED.  STRONG SHORTWAVE TROUGH IS
BECOMING BETTER DEFINED IN MOISTURE CHANNEL IMAGERY AND IS
ACCELERATING EWD ACROSS CENTRAL/SRN ALBERTA AS OF 5/530Z. 
OPERATIONAL/DETERMINISTIC MODELS AND MOST MEMBERS OF SREF GUIDANCE
PACKAGES ARE IN GOOD AGREEMENT WITH DAY-2 TRACK OF THIS SYSTEM ENEWD
ACROSS NRN ONT...AND ALSO NOW...WITH ITS CHARACTER AS INITIALLY
CLOSED LOW EVOLVING INTO OPEN WAVE TROUGH.

ASSOCIATED SFC CYCLONE SHOULD BE NEARLY VERTICALLY STACKED WITH
MID/UPPER LOW BY 6/12Z.  THIS CYCLONE SHOULD LIKEWISE EJECT ENEWD IN
OCCLUDED FORM AND WEAKEN...WHILE TRAILING COLD FRONT MOVES EWD
ACROSS GREAT LAKES REGION.  FRONT SHOULD MOVE SEWD OVER IA/NRN
MO...NRN KS AND PORTIONS WRN CO BY END OF PERIOD.

BROAD AREAS OF CONDITIONAL AND/OR MRGL SVR POTENTIAL ARE APPARENT
FOR DAY-2...HOWEVER ENOUGH UNCERTAINTIES EXIST FOR EACH AREA THAT
PRECLUDE CATEGORICAL OUTLOOK THIS SOON.

...UPPER GREAT LAKES...EARLY-MID PERIOD...
MCS WITH POTENTIAL FOR STG-SVR GUSTS AND HAIL MAY BE ONGOING EARLY
IN PERIOD AHEAD OF SFC COLD FRONT...ACROSS PORTIONS LS...WI...LM AND
UPPER MI.  POTENTIAL WOULD CARRY OVER FROM DAY-1 PERIOD...REF SPC
DAY-1 OUTLOOK FOR MORE DETAILS.  SUCH ACTIVITY SHOULD DIMINISH
THROUGH EARLY MORNING...AS LLJ DIMINISHES IN ASSOCIATION WITH
RECOUPLING OF BOUNDARY LAYER.  SOME REVITALIZATION OF CONVECTION IS
POSSIBLE DURING LATE MORNING THROUGH EARLY AFTERNOON ACROSS LOWER
MI...LH...SWWD OVER PORTIONS NERN IL...SRN LM...SRN WI AND INDIANA. 
WITH MID/UPPER TROUGH EJECTING AWAY FROM AREA...RELATED ISALLOBARIC
FORCING SHOULD YIELD VEERED BOUNDARY LAYER FLOW AND WEAKENING
CONVERGENCE.  ALSO...CLOUD/CONVECTIVE DEBRIS FROM EARLY ACTIVITY MAY
LIMIT PREFRONTAL SFC HEATING.  DEEP-LAYER FLOW FIELDS SHOULD BE
NEARLY UNIDIRECTIONAL. MAIN THREAT WITH ANY SUSTAINED ACTIVITY
WOULD BE DAMAGING GUSTS.

...MID MS VALLEY REGION TO CENTRAL LOW PLAINS...AFTERNOON...
CONDITIONAL SVR POTENTIAL EXISTS INVOF SFC FRONT ACROSS THIS REGION.
 STRONG CAPPING MAY PRECLUDE DIURNAL DEVELOPMENT ALTOGETHER...BUT
ANY TSTMS THAT DO FORM WILL BE SUPPORTED BY FAVORABLE INSTABILITY. 
OVER IA/IL/NRN MO...EVAPOTRANSPIRATIVELY AIDED SFC MOISTURE WILL BE
HIGH WITH DEW POINTS 70S TO LOW 80S F...AND STRONG SFC
HEATING...CONTRIBUTING TO MLCAPES 2000-3000 J/KG...POTENTIALLY MORE.
 STRONGER HEATING BUT DEEPER MIXING AND WEAKER MOISTURE ARE EXPECTED
WITH WWD EXTENT ACROSS KS.  DEEP-LAYER SHEAR PROFILES ALSO SHOULD
WEAKEN WITH SWWD EXTENT.  ISOLATED DAMAGING GUSTS AND LARGE HAIL MAY
DEVELOP...HOWEVER THREAT APPEARS TOO DIFFUSELY DISTRIBUTED ATTM TO
APPLY MORE CONCENTRATED SVR PROBABILITIES.

...CENTRAL HIGH PLAINS...FOOTHILLS...
NELY/POST-FRONTAL FLOW WILL ADVECT MOISTURE UPSLOPE INTO THIS
REGION...AND ENHANCE VERTICAL DIRECTIONAL SHEAR.  THIS SHOULD
CONTRIBUTE TO POTENTIAL FOR TSTMS DEVELOPMENT BY MID-LATE AFTERNOON
OVER TYPICALLY FAVORED TOPOGRAPHIC FEATURES...WITH HAIL OR ISOLATED
WIND DAMAGE POSSIBLE FROM MOST INTENSE CELLS.  CONCERNS PRECLUDING
MORE ROBUST SVR THREAT INCLUDE WEAK MIDLEVEL LAPSE RATES --
ASSOCIATED WITH ABUNDANT/PRECURSORY CONVECTION AND CLOUD COVER
UPSTREAM...AND SMALL VALUES OF DEEP-LAYER BULK SHEAR THAT ARE
LIKELY.

...SERN CONUS...
SCATTERED TSTMS ARE EXPECTED TO DEVELOP AGAIN THIS AFTERNOON IN BOTH
PULSE AND MULTICELLULAR MODES. VERTICAL WIND AND SHEAR PROFILES
WILL REMAIN WEAK OVER THIS REGION...AND ANY SVR POTENTIAL WILL BE
STRONGLY DEPENDENT ON RELATIVELY TRANSIENT MESOSCALE PROCESSES YET
TO BE RESOLVED IN PROGS.  SOME MULTICELL CLUSTERS MAY BECOME
PERSISTENT AND WELL-ORGANIZED ENOUGH TO DEVELOP COLD POOLS TO AID IN
FORWARD PROPAGATION...GENERALLY WWD OR SWWD...PRODUCING
CONCENTRATION OF DAMAGING WIND AND/OR MRGL SVR HAIL REPORTS.  IN
GENERAL...STRONG SFC HEATING AND DEW POINTS UPPER 60S TO MID 70S F
WILL SUPPORT WEAKENING CAP DURING AFTERNOON...PARTICULARLY NEAR
OUTFLOW BOUNDARIES FROM PRIOR AND ONGOING CONVECTION.

...ERN GREAT LAKES...LATE PERIOD...
AHEAD OF SFC FRONT...MOIST ADVECTION ASSOCIATED WITH SWLY LLJ MAY
SUPPORT DEVELOPMENT OF TSTMS ACROSS PORTIONS SRN ONT...LE...AND
PERHAPS PORTIONS OH/WRN PA/WRN NY DURING LAST SEVERAL HOURS OF
PERIOD.  DAMAGING GUSTS WOULD BE PRIMARY CONCERN.  STRONGEST
DEEP-LAYER FORCING SHOULD REMAIN FARTHER N IN CANADA...BUT MOST
FAVORABLE BUOYANCY COULD EXTEND SWD OVER ERN GREAT LAKES REGION. 
THIS POTENTIAL IS MORE STRONGLY INDICATED BY OPERATIONAL WRF THAN
MOST OTHER MODELS.  FCST SOUNDINGS SUGGEST SUFFICIENTLY STEEP
MIDLEVEL LAPSE RATES AND MOISTURE JUST OFF SFC FOR MUCAPES ABOVE
1500 J/KG IN PROSPECTIVE INFLOW LAYER...AND SFC THETAE LARGE ENOUGH
THAT EFFECTIVE PARCELS MAY BE BASED NEAR GROUND.

..EDWARDS.. 08/05/2006