[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 171629
SWODY1
SPC AC 171627

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CDT MON JUL 17 2006

VALID 171630Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT FROM ERN IA TO MI....

...MS VALLEY/GREAT LAKES AREA THIS AFTERNOON INTO TONIGHT...
A MID LEVEL SHORTWAVE TROUGH OVER ONTARIO...WITH A LOBE EXTENDING
SWD OVER MN/WI...WILL MOVE GENERALLY EWD OVER THE GREAT LAKES
THROUGH EARLY TUESDAY. AN ASSOCIATED SURFACE COLD FRONT WILL
CONTINUE SEWD ACROSS IA/WI/NRN IL/MI BY LATE TONIGHT.  THIS SURFACE
FRONT WILL PROVIDE A FOCUS FOR THUNDERSTORM DEVELOPMENT THIS
AFTERNOON INTO TONIGHT ACROSS THE SLIGHT RISK AREA.

SURFACE ANALYSES AND 12Z SOUNDINGS SHOW LOWER 70S BOUNDARY LAYER
DEWPOINTS BENEATH A PLUME OF 8-9 C/KM MID LEVEL LAPSE RATES WITHIN
THE WARM SECTOR.  WHEN COMBINED WITH AFTERNOON TEMPERATURES IN THE
90S...STRONG INSTABILITY /MLCAPE VALUES FROM 3000-4000 J/KG/ WILL BE
PRESENT FROM ERN IA NEWD INTO LOWER MI BY MID-LATE AFTERNOON.  THE
ELEVATED MIXED LAYER SHOULD CONFINE THUNDERSTORM DEVELOPMENT TO THE
IMMEDIATE FRONTAL ZONE BY 21-00Z WHERE DEEP MIXING/ASCENT WILL
REMOVE CONVECTIVE INHIBITION.  THE STRONG INSTABILITY AND MODEST
DEEP LAYER VERTICAL SHEAR MAY SUPPORT A FEW SUPERCELLS AND/OR BOWING
SEGMENTS WITHIN A THE BAND OF STORMS ALONG THE FRONT.  LARGE
HAIL...SOME OF WHICH COULD BE QUITE LARGE GIVEN THE VERY STEEP MID
LEVEL LAPSE RATES...AND DAMAGING WINDS WILL BE THE PRIMARY SEVERE
THREATS THIS AFTERNOON INTO EARLY TONIGHT.

...CENTRAL/SRN AZ...SE CA...EXTREME SRN NV THIS AFTERNOON/EVENING...

A PRONOUNCED WAVE IN THE ELYS IS NOW MOVING OVER NRN BAJA. 
RELATIVELY RICH LOW-MID LEVEL MOISTURE HAS OVERSPREAD MUCH OF
CENTRAL/SRN AZ AND SE CA IN ASSOCIATION WITH THIS WAVE...AND SEVERAL
CLUSTERS OF THUNDERSTORMS WILL LIKELY FORM AGAIN TODAY OVER RIM IN
AZ AND OTHER MORE LOCALIZED TERRAIN FEATURES.  AFTERNOON MLCAPE
VALUES OF 1000-1500 J/KG AND 25-30 KT ELY/ESELY MID LEVEL FLOW
SHOULD SUPPORT A FEW ORGANIZED MULTICELL CLUSTERS THAT WILL MOVE WWD
OFF THE HIGHER TERRAIN THIS AFTERNOON/EVENING. THE STRONGEST STORMS
COULD PRODUCE ISOLATED DAMAGING OUTFLOW WINDS AND MARGINALLY SEVERE
HAIL.

...GULF COAST THIS AFTERNOON...
A REMNANT MID LEVEL CYCLONIC CIRCULATION HAS DRIFTED SSWWD OVER SRN
MS/SE LA...AND A WEAK NW-SE ORIENTED SURFACE TROUGH/FRONT PERSISTS
FROM NRN LA INTO SRN MS/AL.  MODIFIED MORNING SOUNDINGS SHOW THE
POTENTIAL FOR STRONG INSTABILITY THIS AFTERNOON AND MINIMAL
CONVECTIVE INHIBITION WITH SURFACE TEMPERATURES IN THE LOWER 90S. 
THE STRONGEST STORMS MAY PRODUCE ISOLATED DAMAGING DOWNBURST WINDS
GIVEN THE STRONG INSTABILITY...SOME DRY AIR ALOFT...AND STEEP
LOW-LEVEL LAPSE RATES THIS AFTERNOON.

..THOMPSON/CROSBIE.. 07/17/2006