[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 290605
SWODY1
SPC AC 290603

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0103 AM CDT SAT JUL 29 2006

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS SERN ND TO LOWER MI...

...SYNOPSIS...
NRN STREAM PATTERN WILL BE CHARACTERIZED BY MEAN RIDGING OVER
CENTRAL/NRN PLAINS...AND HEIGHT FALLS OVER PACIFIC NW LATE IN PERIOD
AHEAD OF PROGRESSIVE TROUGH NOW OFFSHORE BC.  MIDDLE/UPPER LEVEL LOW
-- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY INVOF AZ/NM BORDER -- IS
EXPECTED TO WEAKEN GRADUALLY.  PART OF ITS VORTICITY FIELD MAY SHIFT
NEWD ACROSS SRN CO AGAIN...WITH THE REST WEAKENING OVER AZ.  AT
SFC...PRONOUNCED FRONTAL ZONE WILL EXTEND FROM COMBINED
LEE-SIDE/FRONTAL-WAVE LOW OVER SD...EWD ACROSS MN THEN ESEWD OVER
LOWER MI.  FRONT WILL BE SHIFTED SWD ON MESOSCALE BY MCS OUTFLOWS.

...UPPER GREAT LAKES...UPPER MIDWEST...
TWO PRINCIPAL SVR EPISODES ARE POSSIBLE ACROSS THIS
REGION...INITIALLY WITH EWD EXTENSION OF MCS NOW OVER ND/NERN
SD...AND SUBSEQUENTLY WITH AFTERNOON/EVENING DEVELOPMENT ALONG AND N
OF FRONTAL/OUTFLOW BOUNDARY LEFT BEHIND BY FIRST COMPLEX.  TO SOME
EXTENT...LARGEST SVR PROBABILITIES REPRESENT SPATIAL OVERLAY OF
BOTH.

ONGOING STRONG-SVR TSTMS ACROSS PORTIONS WI...AS OF 05Z...CONTINUE
TO MOVE SFC BAROCLINIC ZONE FRONT SWD ACROSS THAT REGION.  THIS
PROCESS WILL BE REINFORCED BY MCS NOW PRIMARILY OVER ND.  MEANWHILE
COMBINATION OF CLOUD DEBRIS...AREAS OF PRECIP AND LACK OF
SUBSTANTIAL ISALLOBARIC FORCING WILL KEEP FRONTAL ZONE ALONG OR JUST
S OF PRESENT POSITION ACROSS MI.  THEREFORE FAVORABLE MCS CORRIDOR
SHOULD BE FROM E-CENTRAL/NERN MN ESEWD ACROSS CENTRAL WI AND CENTRAL
LOWER MI INITIALLY...AS BOUNDARY LAYER HEATS ACROSS THIS REGION AND
AHEAD OF REMAINS OF CURRENT DAKOTAS COMPLEX.  DAMAGING GUSTS AND
ISOLATED HAIL ARE POSSIBLE.  FARTHER W...RELATIVELY STEEP LAPSE
RATES ALOFT...VIGOROUS SFC HEATING AND LIFT INVOF BOUNDARY SHOULD
OVERCOME STRONG CINH...LEADING TO AFTERNOON/EVENING INITIATION FROM
ERN ND ACROSS CENTRAL MN.

VERTICAL SHEAR PROFILES WILL BE FAVORABLE FOR SUPERCELLS AND BOW
ECHOES IN BOTH REGIMES...ESPECIALLY WITHIN SFC FRONTAL ZONE WHERE
BULK SHEAR...VORTICITY...STORM-RELATIVE INFLOW AND SRH ALL SHOULD BE
MAXIMIZED.  GREATEST AFTERNOON MLCAPES...PERHAPS REACHING 3000-4000
J/KG RANGE...ARE EXPECTED OVER WRN REGIME.  EVOLUTION OF SECOND MCS
WITH DAMAGING GUSTS AND LARGE HAIL IS POSSIBLE ESEWD ACROSS MN...AND
OVERNIGHT INTO WI.

...LOWER GREAT LAKES...
WIDELY SCATTERED TO ISOLATED TSTMS MAY DEVELOP ACROSS NRN OH/NWRN
PA/WRN NY REGION DURING AFTERNOON...AMIDST STRONG SFC HEATING AND
FAVORABLE MOISTURE...WITH LOCALIZED/MRGL SVR POTENTIAL.  BETTER
ORGANIZED BUT MORE CONDITIONAL SVR THREAT EXISTS IN ASSOCIATION WITH
POTENTIAL MCS MOTION INTO THIS AREA...FROM LOWER MI AND/OR SRN ONT. 
THIS POTENTIAL ALSO MAY BE SUPPORTED BY ANY MCV OR CONVECTIVELY
ENHANCED/PRE-EXISTING PERTURBATIONS SUCH AS THAT EVIDENT NOW OVER
NWRN MN/NERN SD.  SOME PART OF THIS AREA MAY BE ADDED TO CATEGORICAL
SLGT RISK AS DIURNAL DESTABILIZATION PATTERNS AND UPSTREAM
CONVECTIVE TRENDS WARRANT.

...SWRN CONUS...
ISOLATED STRONG-SVR TSTMS MAY DEVELOP THIS AFTERNOON/EVENING OVER
THIS REGION...HOWEVER BOTH KINEMATIC AND THERMODYNAMIC PROFILES
APPEAR LESS FAVORABLE FOR ORGANIZED SVR EVENT OVER REGION AS A
WHOLE. CLOUD DEBRIS AND DEEP-LAYER LAPSE RATE STABILIZATION BY
ONGOING ACTIVITY WILL DELAY AIR MASS RECOVERY ESPECIALLY OVER
WRN/NRN AZ.  POCKETS OF FAVORABLE DESTABILIZATION ARE POSSIBLE
ACROSS THIS AREA DURING MID-LATE AFTERNOON...RESULTING IN LOCALIZED
STRONG HEATING OF HIGHER TERRAIN AND DEEPLY MIXED BOUNDARY LAYERS
ACROSS DESERT AREAS.  AREA OF MIDLEVEL NELY FLOW SHOULD WEAKEN...AS
WELL AS SHRINK IN BOTH HORIZONTAL AND VERTICAL EXTENT...AS RELATED
MID/UPPER LEVEL LOW BECOMES MORE POORLY DEFINED.  STILL...A FEW
TSTMS MAY FORM OVER HIGHER ELEVATIONS OF NRN AZ AND MOVE SWWD WITH
DAMAGING GUSTS BEING MAIN CONCERN. ACROSS SERN AZ/SWRN NM...MORE
PROLONGED HEATING IS POSSIBLE...BUT DEEP-LAYER FLOW WILL BE WEAKER
WITH MORE WLY COMPONENT ALOFT. SVR POTENTIAL SHOULD BE RATHER
SPORADIC AND DISORGANIZED.

...SERN CONUS...
SCATTERED TSTMS IN CLUSTERS...WITH ISOLATED DAMAGING WIND OR
MARGINALLY SVR HAIL...WILL BE POSSIBLE OVER VERY BROAD SWATH OF SERN
STATES.  POTENTIAL WILL BE CONCENTRATED AROUND SEA BREEZE
FRONTS...MESOSCALE DIFFERENTIAL HEATING BOUNDARIES RELATED TO
PRECURSORY CLOUD/PRECIP PATTERNS...AND OUTFLOW INTERSECTIONS.
BUOYANCY MAY BE MAXIMIZED ACROSS ERN PIEDMONT/COASTAL PLAIN OF
AL...GA AND CAROLINAS. IN THAT CORRIDOR...SUCH BOUNDARIES WILL BE
MOST COMMON...ALONG WITH SFC DEW POINTS IN 70S F AND STRONG
AFTERNOON HEATING IN RELATIVELY CLOUD-FREE AREAS.  MAIN MODE WILL BE
MULTICELLULAR AND PULSE IN NATURE BECAUSE OF WEAK DEEP-LAYER FLOW
AND LACK OF VERTICAL SHEAR.

...NRN HIGH PLAINS...
ELY SFC FLOW COMPONENT N OF SFC FRONT...AND NW OF SFC LOW...WILL ACT
TO TRANSPORT MOISTURE INTO ERN MT...AS WELL AS TO ENHANCE DEEP-LAYER
SHEAR AND WEAKLY AID IN LOW LEVEL ASCENT.  THIS WILL LEAD TO
POTENTIAL FOR WIDELY SCATTERED TSTMS BY MID-LATE AFTERNOON AS SFC
HEATING AND UPSLOPE LIFT WEAKEN SBCINH.  ADVECTION SHOULD YIELD
ENOUGH BOUNDARY LAYER MOISTURE TO YIELD FAVORABLE MLCAPES --
1000-1500 J/KG BASED ON MODIFIED WRF SOUNDINGS -- HOWEVER SUBCLOUD
LAYERS STILL WILL BE RELATIVELY DRY AND WELL-MIXED.  THIS FAVORS
POTENTIAL FOR DAMAGING GUSTS AND HAIL WITH MOST INTENSE CELLS.

..EDWARDS/GRAMS.. 07/29/2006