[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 171243
SWODY1
SPC AC 171241

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CDT MON JUL 17 2006

VALID 171300Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL GREAT LAKES
SWWD INTO NRN IL AND ERN IA....

...SYNOPSIS...
UPPER RIDGE AXIS WILL REMAIN ANCHORED E-W ACROSS MOST OF THE CONUS
...THOUGH A STRONG SHORTWAVE TROUGH WILL MOVE ESEWD THROUGH SRN
ONTARIO AND LOWER HEIGHTS ACROSS THE GREAT LAKES REGION DURING THE
PERIOD. AN ASSOCIATED COLD FRONT...CURRENTLY MOVING THROUGH THE WRN
GREAT LAKES...IS FORECAST TO EXTEND FROM NRN LOWER MI SWWD INTO
SOUTH CENTRAL IA/NORTH CENTRAL KS BY LATE AFTERNOON.

...CENTRAL UPPER MS VLY NEWD INTO THE CNTRL GRTLKS REGION...
STRONG CAPPING INVERSION WILL ONCE AGAIN PLAY HAVOC WITH TIMING AND
LOCATION OF SEVERE STORMS TODAY...THOUGH COOLING ALOFT AND LARGE
SCALE ASCENT SHOULD WEAKEN THE INVERSION ENOUGH FOR SURFACE BASED
STORMS TO DEVELOP ALONG THE FRONT THIS AFTERNOON. THIS 
MORNING...MOSTLY NON-SEVERE ELEVATED CONVECTION IS EXPECTED
ACROSS SERN MN/NWRN IA/U.P./WI...AHEAD OF A WEAK SUBTROPICAL
SHORTWAVE TROUGH LOCATED IN CENTRAL MN. THERE IS A SMALL CHANCE THAT
STORMS EAST OF LAKE SUPERIOR COULD BACKBUILD INTO THE ERN U.P. THIS
MORNING AS THE CAP SLOWLY WEAKENS.

INTENSE SURFACE BASED STORMS ARE MOST LIKELY TO DEVELOP MID/LATE
AFTERNOON FROM NRN/CENTRAL LOWER MI SWWD INTO SRN WI...AND
EVENTUALLY ERN IA AS THE STORMS BACKBUILD SWWD ALONG THE FRONT. ONCE
SURFACE BASED STORMS DEVELOP...THEY WILL BE LOCATED WITHIN A VERY
UNSTABLE AIRMASS WITH MLCAPES FROM 3000 TO 4000 J/KG. THE DEGREE OF
INSTABILITY COMBINED WITH 40 KT DEEP LAYER SHEAR WILL BE FAVORABLE
FOR SUPERCELLS. THE AMOUNT OF INSTABILITY SHOULD SUPPORT VERY LARGE
HAIL...ESPECIALLY THE FIRST FEW HOURS AFTER INITIATION SINCE THE
STORMS ARE EXPECTED TO BE CELLULAR. THEREAFTER...THE OUTFLOWS SHOULD
MERGE INTO A SEWD MOVING LINE ALONG THE FRONT... WITH WIND DAMAGE
BECOMING THE MAIN SEVERE THREAT AS THE STORMS MOVE INTO SRN LOWER MI
AND NRN IL DURING THE EVENING. HOWEVER... THE LOW LEVEL JET AND MASS
CONVERGENCE ARE FORECAST TO WEAKEN OVERNIGHT...SO THE STORMS SHOULD
WEAKEN AS THEY MOVE SEWD INTO NRN INDIANA/CENTRAL IL OVERNIGHT.

...SWRN DESERTS...
WEAK UPPER LEVEL CIRCULATION SHOULD CONTINUE MOVING SLOWLY WWD INTO
SRN CA TODAY. THE MOIST AND UNSTABLE ENVIRONMENT PLUS THE LIFT
ASSOCIATED WITH THE UPPER LOW SHOULD ONCE AGAIN INITIATE AFTERNOON
THUNDERSTORMS OVER THE RIM. WITH 35 KT ELY MID LEVEL WINDS...THESE
STORMS SHOULD MOVE WWD INTO THE LWR DESERTS TOWARD THE LOWER CO
RIVER VALLEY DURING THE LATE AFTERNOON/EVENING HOURS. ALTHOUGH
ISOLATED WIND DAMAGE IS POSSIBLE...THE WIND THREAT MAY BE  LOWER
THAN THE PAST FEW DAYS DUE TO THE STRONG CONVECTIVE OVERTURNING.

...GULF COASTAL REGION...
A DIFFUSE SURFACE TROUGH AND WEAK CAPPING SHOULD RESULT IN SCATTERED
THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON...ROUGHLY WITHIN 100
NM OF THE GULF COAST FROM SERN TX TO THE FL PANHANDLE. A HOT AND
MOIST BOUNDARY LAYER WILL FAVOR MULTICELL CLUSTERS WITH A POTENTIAL
FOR BRIEF STRONG DOWNBURSTS. THE STORMS SHOULD DIE OUT QUICKLY AFTER
01Z WITH LOSS OF DAYTIME HEATING.

..IMY/JEWELL.. 07/17/2006