[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 011650
SWODY2
SPC AC 011649

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1149 AM CDT SUN OCT 01 2006

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPPER
MIDWEST...

...SYNOPSIS...

PROGRESSIVE LARGE-SCALE PATTERN IS FORECAST DURING THE DAY TWO
PERIOD WITH SEVERAL WEAK PERTURBATIONS EMBEDDED IN BROAD WSWLY FLOW
REGIME FROM THE GREAT BASIN INTO THE UPPER MIDWEST.  IN THE
LOW-LEVELS...SURFACE FRONT WILL SLOWLY SAG SWD THROUGH THE UPPER
GREAT LAKES WITH WRN EXTENSION OF THIS BOUNDARY REMAINING
QUASI-STATIONARY OR PERHAPS RETREATING NWD SLIGHTLY AS LOW PRESSURE
INTENSIFIES OVER NEB.

...UPPER MIDWEST...

CLUSTERS OF ELEVATED TSTMS...FOCUSED WITH ZONE OF ENHANCED
MOIST/THERMAL ADVECTION ALONG NOSE OF 40-45 KT WSWLY LLJ...WILL
LIKELY DEVELOP EWD ACROSS LOWER MI MONDAY MORNING.  WHILE VERTICAL
SHEAR THROUGH THE CLOUD-BEARING LAYER WILL NOT BE PARTICULARLY
STRONG...THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES AND RESULTANT
MUCAPES OF 1000-1500 J/KG MAY SUPPORT SOME MARGINALLY SEVERE HAIL
WITH THE MOST INTENSE STORMS.

OTHER DIURNAL...SURFACE-BASED STORMS WILL BE POSSIBLE MONDAY
AFTERNOON INTO EVENING ALONG SURFACE FRONT SLOWLY PUSHING SWD
THROUGH WI.  PRESENCE AND/OR TIMING OF ANY SIGNIFICANT SHORT WAVE
TROUGHS TO FOCUS THIS CONVECTION REMAINS IN QUESTION ATTM...LEADING
TO UNCERTAINTY IN CONVECTIVE EVOLUTION AND INHERENT SEVERE WEATHER
THREAT.  NONETHELESS...INCREASING BOUNDARY LAYER MOISTURE BENEATH
PLUME OF STEEP MID-LEVEL LAPSE RATES WILL CONTRIBUTE TO MODERATE
AFTERNOON INSTABILITY WITH MLCAPES OF 1000-2000 J/KG.

CAPPING WILL BE AN ISSUE...BUT LATEST MODEL GUIDANCE DOES SUGGEST
THAT THE INITIATION OF DEEP...MOIST CONVECTION WILL OCCUR BY MID TO
LATE AFTERNOON OVER CNTRL OR SRN WI.  VERTICAL SHEAR WILL BE MODEST
/I.E. EFFECTIVE BULK SHEARS AOB 30-35 KT/ THOUGH THE DEGREE OF
INSTABILITY WILL SUPPORT A FEW SEVERE STORMS CAPABLE OF LARGE HAIL
AND LOCALLY DAMAGING WINDS.

ADDITIONAL MORE ELEVATED STORMS WILL BE POSSIBLE MONDAY NIGHT WWD
INTO SRN MN/NRN IA AS INCREASING NOCTURNAL LLJ ENHANCES CONVERGENCE
ALONG SURFACE BOUNDARY.  EXISTING CAP WILL REMAIN
PROBLEMATIC...THOUGH ISOLATED STORMS APPEAR POSSIBLE WITH A THREAT
OF MARGINALLY SEVERE HAIL AND/OR LOCALLY STRONG WIND GUSTS.

..MEAD.. 10/01/2006