[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 311256
SWODY1
SPC AC 311254

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0754 AM CDT MON JUL 31 2006

VALID 311300Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPR MS VLY
AND UPR GRT LKS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF UPSTATE NY AND
WRN NEW ENGLAND...

...SYNOPSIS...
DOMINANT MS VLY UPR RIDGE WILL EXPAND E AND SLIGHTLY N INTO THE UPR
OH VLY/MID ATLANTIC REGION THIS PERIOD AS SHORTWAVE TROUGH NOW
ENTERING SASKATCHEWAN CONTINUES E INTO WRN ONTARIO.  FARTHER W...
DISTURBANCE NOW NEARING THE NRN CA CST SHOULD REACH THE NRN GRT
BASIN BY 12Z TUESDAY.

COLD FRONT ACCOMPANYING SASKATCHEWAN TROUGH...NOW EXTENDING FROM NE
ND INTO NW NEB LIKELY WILL CONTINUE ONLY SLOWLY SE INTO THE CNTRL
PLNS ...BUT SHOULD PROGRESS STEADILY E ACROSS THE UPR MS VLY/UPR GRT
LKS BY TONIGHT/EARLY TUESDAY.

...UPR MS VLY/UPR GRT LKS...
CONVECTIVE SYSTEMS NOW OVER WRN LK SUPERIOR AND THE ERN U.P. OF MI
SHOULD CONTINUE GENERALLY ESE INTO ONTARIO LATER THIS MORNING...
AHEAD OF SLOWLY EXPANDING UPR RIDGE.  STRONG LOW-LEVEL WARM
ADVECTION FROM THE WEST MAY SUPPORT BACK-BUILDING/REGENERATIVE
ACTIVITY ON THE SWRN FLANKS OF THESE SYSTEMS.  SOME OF THE STORMS
COULD AFFECT NRN AND ERN PARTS OF THE U.P...AND POSSIBLY EXTREME NRN
LWR MI...WITH LOCALLY DAMAGING WIND.  BUT THE BULK OF THIS SLIGHTLY
ELEVATED ACTIVITY SHOULD REMAIN IN CANADA.

FARTHER W...A BAND OR TWO OF ELEVATED STORMS MAY PERSIST THROUGH
MIDDAY IN POST-FRONTAL/POST CONVECTIVE OUTFLOW ENVIRONMENT IN NRN
MN/ERN ND.  RELATIVELY WARM MID LEVEL TEMPERATURES AND WEAK LARGE
SCALE ASCENT SHOULD LIMIT POTENTIAL FOR SUSTAINED STORMS WITH HAIL.

LATER TODAY...EXPECT THAT SURFACE HEATING AND WEAK ASCENT S OF
PASSING TROUGH WILL INITIATE SURFACE-BASED STORMS ALONG COLD FRONT
IN NRN/CNTRL MN AND THE ERN DAKOTAS.  WARM MID LEVEL TEMPERATURES
WILL CONTINUE TO LIMIT DEGREE OF DIURNAL DESTABILIZATION.  BUT VERY
WARM...FAIRLY MOIST AND DEEPLY-MIXED BOUNDARY LAYER SHOULD YIELD
MLCAPE OF 1500-3000 J/KG.  UNIDIRECTIONAL MID LEVEL WSWLY FLOW ON
SRN FRINGE OF CANADIAN TROUGH SHOULD INCREASE TO AROUND 50 KTS
ACROSS NRN MN...AND TO AOA 30 KTS IN ERN SD/SRN MN.  DEEP LAYER OF
LARGELY UNIDIRECTIONAL FLOW...HI PWS AND DEEP MIXED LAYERS ALL
SUGGEST POTENTIAL FOR ORGANIZATION INTO LINES/CLUSTERS...WITH
EMBEDDED SUPERCELLS SUPPORTING BOWING SEGMENTS WITH HIGH WINDS AND
POSSIBLY HAIL.    POTENTIAL FOR SUSTAINED SEVERE SHOULD DECREASE
WITH SWD EXTENT...BUT MAY CONTINUE INTO TONIGHT EWD INTO WI/UPR MI.

...NY/NEW ENGLAND...
EWD EXPANSION OF CNTRL STATES RIDGE WILL ENHANCE WARM ADVECTION
ACROSS SRN ONTARIO AND THE ST LAWRENCE RVR VLY LATER TODAY THROUGH
EARLY TUESDAY. THIS SHOULD SUSTAIN TSTM CLUSTERS/MCSS THAT WILL
AFFECT SRN ONTARIO LATER TODAY.  THIS ACTIVITY MAY BEGIN TO
FORWARD-PROPAGATE SE INTO PARTS OF UPSTATE NY AND WRN NEW ENGLAND
LATE TONIGHT/EARLY TUESDAY AS DOWNSTREAM BOUNDARY LAYER WARMS/
MOISTENS.  WHILE FORECAST SOUNDINGS INDICATE THAT INSTABILITY WILL
REMAIN MARGINAL...RELATIVELY STRONG UNIDIRECTIONAL DEEP WIND FIELDS
MAY SUPPORT LOCALLY DAMAGING WINDS.

...CNTRL/SRN HIGH PLAINS...
STEEP LOW LEVEL LAPSE RATES WILL DEVELOP WITH AFTERNOON HEATING
INVOF COLD FRONT LEE TROUGH SETTLING S/SE ACROSS THE CNTRL HIGH
PLAINS.  WHILE VERTICAL SHEAR WILL REMAIN WEAK...DEEPLY-MIXED
ENVIRONMENT WITH VERY WARM SURFACE TEMPERATURES MAY SUPPORT A FEW
PULSE STORMS WITH HIGH WIND.

...CNTRL/ERN NV...
ENVIRONMENT MAY SUPPORT A FEW STRONG TSTMS THIS AFTERNOON AND
EVENING AS FORCING FOR ASCENT WITH NRN CA TROUGH AND DAYTIME HEATING
DESTABILIZE REGION.  WHILE INSTABILITY LIKELY WILL REMAIN FAIRLY
MARGINAL /SBCAPE AROUND 500 J PER KG/...VERTICAL SHEAR WILL
STRENGTHEN AND MAY SUPPORT DEVELOPMENT OF A FEW ORGANIZED STORMS
CAPABLE OF DAMAGING WIND AND POSSIBLY MARGINALLY SEVERE HAIL.

..CORFIDI/GRAMS.. 07/31/2006