[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 191235
SWODY1
SPC AC 191234

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0734 AM CDT WED JUL 19 2006

VALID 191300Z - 201200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF SERN
MN...NERN IA AND SWRN WI...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MS RIVER
VALLEY EWD TO THE GREAT LAKES...

...SYNOPSIS...
WESTERLIES WILL REMAIN ACROSS THE NRN FOURTH OF THE COUNTRY...WHILE
A LARGE UPPER RIDGE CONTINUES ITS HOLD OVER THE REST OF THE NATION.
THE MAJOR FEATURE FOR SEVERE CONVECTION WILL BE A SHORTWAVE
TROUGH...ASSOCIATED 60-70 KT MID LEVEL JET MAX AND COLD FRONT MOVING
FROM THE DAKOTAS EWD INTO THE WESTERN GREAT LAKES DURING THIS
PERIOD. A WARM FRONT ACROSS THE MO RIVER VALLEY WILL SHIFT NWD INTO
SRN MN/WI THIS AFTERNOON.

...UPPER MS VLY/CNTRL GRTLKS...
BAND OF ELEVATED THUNDERSTORMS IN WRN MN SHOULD SPREAD E/SEWD THIS
MORNING AS THE LOW LEVEL JET VEERS. MUCAPES 2000+ J/KG AND STEEP
LAPSE RATES INDICATE SEVERE HAIL IS POSSIBLE...BUT WARM MID LEVEL
TEMPERATURES SHOULD LIMIT THE THREAT. EXPECT THE CLOUDS/PCPN FROM
THIS COMPLEX WILL REINFORCE WARM FRONT ACROSS SRN MN THIS AFTERNOON.
VERY WARM TEMPERATURES ALOFT...700 MB TEMPERATURES NEAR 16
DEG...INDICATE A STOUT CAP WILL ALSO BE IN PLACE. HOWEVER...THE
COMBINATION OF LARGE SCALE LIFTING FROM TROUGH/JET MAX AND
CONVERGENCE SHOULD AID RENEWED THUNDERSTORM DEVELOPMENT NEAR COLD
FRONT/BOUNDARY INTERSECTION BETWEEN 19-22Z. ONCE STORMS FORM...THE
AIR MASS WILL BE EXTREMELY UNSTABLE...MLCAPE VALUES IN EXCESS OF
4000 J/KG...AND WITH DEEP LAYER SHEAR NEAR 60 KT...RAPID DEVELOPMENT
OF SUPERCELLS IS EXPECTED. THE BOUNDARY LAYER SHOULD BE QUITE MOIST
NEAR THE WARM FRONT AND STRONGLY CURVED HODOGRAPHS IN THE LOWER 1 KM
INDICATE A POTENTIAL FOR TORNADOES...ALONG WITH VERY LARGE HAIL.
HOWEVER...THE STORMS SHOULD GENERATE STRONG OUTFLOWS THAT MERGE AND
EVOLVE INTO A FORWARD PROPAGATING BOW ECHO/DERECHO AS THE LLJ
BECOMES WLY AND ALIGNS WITH THE STRONG WINDS ALOFT. THE RESULTING
COLD POOL SHOULD ALSO HELP DEVELOP A REAR INFLOW JET WITH WIDESPREAD
DAMAGING WINDS POSSIBLE AS THE SYSTEM MOVES ESEWD ACROSS SERN
MN/NERN IA/SWRN WI. THE LINEAR COMPLEX MAY CONTINUE MOVING SEWD
OVERNIGHT INTO NRN IL AND LOWER MI...BUT THE STABILIZING BOUNDARY
LAYER SHOULD DECREASE THE WIND THREAT.

INTENSE HEATING AND FRONTAL CONVERGENCE MAY BE SUFFICIENT TO LIFT
CAP FOR STORMS TO INITIATE ACROSS EXTREME SERN SD/NWRN IA AND NERN
NEB BETWEEN 21-03Z. ANY STORMS THAT DEVELOP IN THIS DEEPLY MIXED
BOUNDARY LAYER LIKELY WOULD PRODUCE STRONG/SEVERE WINDS. STORMS THAT
DEVELOP SHOULD WEAKEN QUICKLY AFTER SUNSET AS THE CAP BECOMES
REESTABLISHED.

...CNTRAL AND SRN APPALACHIANS...
WEAK FRONT/BOUNDARY COMBINED WITH STRONG HEATING OF A MOIST BOUNDARY
LAYER ACROSS THE CENTRAL/SRN APPALACHIANS SHOULD RESULT IN AFTERNOON
THUNDERSTORM DEVELOPMENT. ENVIRONMENTAL WINDS WILL BE WEAK...BUT
MODERATE INSTABILITY MAY SUPPORT A FEW DAMAGING WIND EVENTS.

...GULF COASTAL STATES...
DIURNAL THUNDERSTORMS WILL ONCE AGAIN BE LIKELY ACROSS THE GULF
COASTAL STATES WITH ISOLATED BRIEF WET MICROBURSTS POSSIBLE.

...SWRN DESERTS...
WIDESPREAD CLOUDS AND A FEW THUNDERSTORMS WERE STILL OCCURRING 
ACROSS AZ THIS MORNING. STRONG HEATING OF THE RELATIVELY MOIST
ENVIRONMENT SHOULD RESULT IN STORMS TO REDEVELOP THIS AFTERNOON.
THE CONVECTIVE OVERTURNING OF STORMS THE PAST FEW DAYS AND WEAK
WINDS ALOFT INDICATE THE THREAT FOR MORE THAN ISOLATED STRONG WIND
GUSTS IS LIMITED.

..IMY/TAYLOR.. 07/19/2006