[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 011256
SWODY1
SPC AC 011255

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT SAT JUL 01 2006

VALID 011300Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT FROM THE CENTRAL HIGH PLAINS TO THE UPPER GREAT LAKES
AREA....

...WI/MI AREA THIS AFTERNOON/EVENING...
A LOW AMPLITUDE SHORTWAVE TROUGH OVER ERN ND/NW MN THIS MORNING WILL
MOVE ESEWD OVER THE UPPER GREAT LAKES REGION LATER THIS AFTERNOON
INTO EARLY TONIGHT.  A SURFACE LOW WILL MOVE ACROSS SRN ONTARIO IN
ADVANCE OF THIS MID LEVEL WAVE...WHILE A TRAILING COLD FRONT
ADVANCES SEWD ACROSS IA/WI/MI THIS AFTERNOON.  SEVERAL DAYS OF
EVAPOTRANSPIRATION HAVE RAISED SURFACE LAYER DEWPOINTS INTO THE
MID-UPPER 60S ACROSS THE CORN BELT...IN THE CORRIDOR ALONG A REMNANT
NW-SE BAROCLINIC ZONE WHERE THE BOUNDARY LAYER HAS BEEN SHELTERED
FROM DEEPER MIXING.  THIS MOIST LAYER IS STILL RELATIVELY
SHALLOW...BUT SHOULD PERSIST TODAY ACROSS IA/WI AND SPREAD NEWD INTO
LOWER MI FROM IL/INDIANA BY AFTERNOON. ADDITIONALLY...A PLUME OF
RELATIVELY STEEP MID LEVEL LAPSE RATES WILL OVERSPREAD THE WI/MI
AREA IN ADVANCE OF THE MID LEVEL TROUGH.  THE STEEP LAPSE
RATES...LOW-LEVEL MOISTURE...AND AFTERNOON TEMPERATURES IN THE
MID-UPPER 80S WILL ALL CONTRIBUTE TO THE DEVELOPMENT OF MLCAPE
VALUES OF 1500-2500 J/KG AHEAD OF THE COLD FRONT BY AFTERNOON.

SCATTERED THUNDERSTORMS SHOULD DEVELOP INVOF THE FRONT ACROSS NRN
WI/WRN UPPER MI BY MID AFTERNOON...WITH ADDITIONAL STORM DEVELOPMENT
EXPECTED FARTHER SW INTO WI AND NE IA BY EVENING.  FORECAST VERTICAL
SHEAR APPEARS SUFFICIENT FOR A FEW SUPERCELLS IN A BROKEN BAND NEAR
THE FRONT...THOUGH SOME OF THE CONVECTION MAY ALSO EVOLVE INTO
BOWING LINE SEGMENTS.  DAMAGING WINDS AND LARGE HAIL WILL THE MAIN
SEVERE THREATS.  THE TORNADO THREAT IS MORE UNCERTAIN AND WILL
DEPEND ON LOCAL ENHANCEMENTS TO LOW-LEVEL MOISTURE IN THE REGION OF
STRONGER LOW-LEVEL SHEAR FROM ERN WI INTO LOWER MI LATER THIS
AFTERNOON/EVENING.

...CENTRAL PLAINS/HIGH PLAINS THIS AFTERNOON INTO TONIGHT...
A SURFACE COLD FRONT IS MOVING SEWD ACROSS NEB AND NE CO AS OF
12Z...THOUGH THE BOUNDARY SHOULD STALL THIS AFTERNOON FROM ERN CO
ACROSS NW KS TO SE NEB AND SRN IA.  STRONG SURFACE HEATING WILL
OCCUR S OF THE BOUNDARY...WHILE SOMEWHAT RICHER MOISTURE AND
MODERATE INSTABILITY WILL BE MAINTAINED IN A NARROW BAND IMMEDIATELY
N OF THE FRONT.  A FEW THUNDERSTORMS SHOULD DEVELOP ALONG THE
BOUNDARY BY LATE AFTERNOON AND PERSIST INTO THE EARLY OVERNIGHT
HOURS. VERTICAL SHEAR WILL BE MARGINALLY FAVORABLE FOR SUPERCELLS N
OF THE BOUNDARY AND IN THE UPSLOPE FLOW AREA OF NE CO/SE WY...WHICH
MAY TEND TO LOCALLY ENHANCE THE THREAT FOR LARGE HAIL. 
OTHERWISE...STORMS SHOULD EVOLVE INTO A FEW SMALL CLUSTERS WITH THE
POTENTIAL TO PRODUCE ISOLATED LARGE HAIL AND DAMAGING WINDS INTO
TONIGHT.

...SE ATLANTIC STATES THIS AFTERNOON...
ONE WEAK MID LEVEL WAVE IS MOVING OFFSHORE OF NC...WHILE OTHER
SUBTLE WAVES ARE LOCATED UPSTREAM OVER TN/KY.  12Z SOUNDINGS SHOW
THE POTENTIAL FOR MODERATE INSTABILITY THIS AFTERNOON ACROSS THE
CAROLINA COASTAL PLAINS WHERE LOW-LEVEL MOISTURE WILL BE MAXIMIZED. 
MORNING SOUNDINGS ALSO REVEAL STEEP LAPSE RATES BELOW 700 MB OVER
THE SRN APPALACHIANS/TN VALLEY.  STRONG SURFACE HEATING WILL RESULT
IN PROFILES THAT MAY SUPPORT ISOLATED STRONG DOWNBURSTS OVER
PORTIONS OF THE SRN APPALACHIANS AND COASTAL CAROLINAS...AS WELL AS
ISOLATED HAIL.

..THOMPSON/GUYER.. 07/01/2006