[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 040615
SWODY2
SPC AC 040614

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0114 AM CDT FRI AUG 04 2006

VALID 051200Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS NERN PLAINS...UPPER MS VALLEY
REGION...

...SYNOPSIS...
MID-UPPER LEVEL...SYNOPTIC-SCALE RIDGING WILL DOMINATE PATTERN FROM
4-CORNERS REGION EWD ACROSS SRN PLAINS TO CAROLINAS.  MEANWHILE
PROGRESSIVE AND GENERALLY ZONAL PATTERN IS EXPECTED TO CHARACTERIZE
NRN STREAM FLOW BELT...ACROSS ROUGHLY NRN 1/4 OF CONUS.  SHORTWAVE
TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CENTRAL/NRN
BC -- IS FCST TO AMPLIFY THROUGH BOTH DAY-1 AND DAY-2...AS IT MOVES
ESEWD ACROSS SASK.  CONSIDERABLE DISAGREEMENT REMAINS IN PROGS OVER
WHETHER THIS SYSTEM WILL EVOLVE INTO CLOSED LOW ACROSS SASK/MANITOBA
DURING PERIOD...GIVEN PROGRESSIVE NATURE OF PATTERN AND PRESENCE OF
OPEN WAVE IN ROUGHLY HALF OF COMBINED SREF/OPERATIONAL 500 MB MODEL
PROGS. MID/UPPER LEVEL LOW - NOW CUT OFF ACROSS TRANS-PECOS AND BIG
BEND REGIONS OF SW TX -- IS EXPECTED TO DRIFT GENERALLY WWD AROUND
MEAN RIDGE TOWARD AZ...CONTRIBUTING TO CLOUDS/PRECIP AND GEN THUNDER
POTENTIAL OVER PORTIONS AZ/NM.

AT SFC...STRONG FRONTOGENESIS LATE DAY-1 AND EARLY DAY-2 OVER NRN
ROCKIES AND NRN HIGH PLAINS WILL LEAD TO COLD FRONT SWEEPING SEWD
ACROSS UPPER MIDWEST AND CENTRAL HIGH PLAINS DURING THIS
PERIOD...WHILE DEEPENING SFC LOW EJECTS FROM ND ENEWD TOWARD NWRN
ONT.  FARTHER S...WEAK COLD FRONTAL ZONE IS ANALYZED FROM ERN GREAT
LAKES ACROSS OZARKS AND RED RIVER REGION...TO E-CENTRAL/SERN NM. 
WRN PORTION OF THIS FRONT SHOULD BECOME DIFFUSE ACROSS SRN PLAINS
DURING DAY-2...AMIDST BROAD SLY/SELY FLOW FETCH THAT WILL DEVELOP IN
RESPONSE TO NRN PLAINS CYCLOGENESIS.  FRONT FARTHER E -- FROM MS/AL
ACROSS GA/SC -- WILL BE MODIFIED/SHIFTED SPATIALLY ON MESOSCALE BY
OUTFLOWS.

...NRN PLAINS TO UPPER MS VALLEY REGION...
LOW LEVEL WAA/ISENTROPIC ASCENT...AND INCREASING MOISTURE ABOVE
SFC...MAY SUPPORT STG-SVR TSTMS FROM NERN ND EWD TO LS EARLY IN
PERIOD...CARRYING OVER THREAT FROM DAY-1.  REF SPC DAY-1 OUTLOOK FOR
MORE INFORMATION ON THIS REGIME.  SECOND AND MORE ROBUST SVR THREAT
WILL DEVELOP DURING AFTERNOON/EVENING ACROSS LARGER PORTION OF THIS
REGION.

AS INTENSE CANADIAN MID-UPPER LEVEL TROUGH APCHS...VERTICAL SHEAR IS
FCST TO STRENGTHEN OVER INCREASINGLY MOIST/UNSTABLE WARM SECTOR AIR
MASS.  THIS WILL RESULT BOTH FROM STRENGTHENING MID-UPPER LEVEL
GRADIENTS AND FROM LOW LEVEL ACCELERATIONS IN WARM SECTOR ASSOCIATED
WITH ISALLOBARIC/ISALLOHYPSIC FORCING. LOW LEVEL HODOGRAPHS FROM
MODEL SOUNDINGS ACROSS PORTIONS MN APPEAR QUITE LARGE AND FAVORABLE
FOR ROTATING STORMS...WITH ATTENDANT THREAT OF HAIL/WIND AND PERHAPS
TORNADOES.  MEANWHILE...LARGE SCALE ASCENT OVER STRONGLY HEATED
BOUNDARY LAYER WILL FAVORABLY STEEPEN DEEP-LAYER LAPSE
RATES...COMBINING WITH EVAPOTRANSPIRATIVELY BOOSTED SFC DEW POINTS
TO GENERATE MDT-STG BUOYANCY.  BY MID-LATE AFTERNOON...SEVERE TSTMS
SHOULD ERUPT INVOF FRONT...AS HEATING AND CONVERGENCE BREAK CAP. 
MCS MAY EVOLVE FROM AFTERNOON ACTIVITY AND MOVE ESEWD-SEWD ACROSS
PORTIONS UPPER MS VALLEY TOWARD WI/IL.

SPECIFIC DISTRIBUTION OF SVR THREATS WILL DEPEND LARGELY ON STORM
MODE AND MESOSCALE PROCESSES NOT WELL-RESOLVED THIS FAR IN ADVANCE. 
OVERALL PATTERN...HOWEVER...SUGGESTS THAT SOME
CONCENTRATION/SIGNIFICANCE OF SVR POTENTIAL SUFFICIENT TO WARRANT
MDT CATEGORICAL OUTLOOK MAY BECOME MORE APPARENT FOR LATER OUTLOOKS.


...SERN CONUS...
SCATTERED TO WIDELY SCATTERED TSTMS IN CLUSTERS ARE FCST ACROSS THIS
REGION...PRIMARILY CONCENTRATED ALONG MESOSCALE FOCI SUCH AS OUTFLOW
BOUNDARIES INVOF FRONTAL ZONE. STRONG HEATING AND MOISTURE ARE
EXPECTED...BUT WITH WEAK VERTICAL SHEAR INVOF MID-UPPER LEVEL RIDGE.
 ACCORDINGLY...WILL INTRODUCE MRGL AND BROAD-BRUSHED SVR
PROBABILITIES FOR PULSE/MULTICELLULAR ACTIVITY.

..EDWARDS.. 08/04/2006