[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 131222
SWODY1
SPC AC 131217

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0717 AM CDT MON SEP 13 2004

VALID 131300Z - 141200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 75 NW
CMX 40 NNW EAU 50 NNE OMA 25 WNW BIE 20 SSE MCK 30 SSW IML 25 W IML
55 SW MHN 20 E ANW 20 W ATY 45 W RRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 E DUG 20 SE SAF 25
E ALS 15 S VEL 50 ESE MLD 35 ESE SUN 80 ESE BNO 20 ENE SLE 25 SSW
HQM ...CONT... 140 NE CMX 25 ESE LSE 15 ENE MHK 55 NNW P28 10 ENE
LAA 30 S LHX 40 NW CAO 30 ENE TCC HOB 65 SSW GDP ...CONT... 20 W MFE
30 W VCT 55 SW LFK 35 SSE BTR 25 NE MCB 25 SW CBM 10 ENE MEM 40 ESE
POF 25 SSE MVN 20 NNW IND 15 ESE MIE 25 SW CMH 30 ESE PKB 25 WNW SSU
20 S AVL 20 ENE AND 40 SSE SPA 35 NE CAE 20 SSE EWN.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN/CNTRL
PLAINS AND UPPER MS VALLEY...

...SYNOPSIS...
WELL ESTABLISHED STRONG UPPER TROUGH WAS POSITIONED OVER THE
INTERIOR NORTHWEST THIS MORNING WITH SURFACE FRONT LOCATED ALONG THE
ERN FLANK OF THE TROUGH...FROM WRN NEB NNEWD INTO ERN ND. MID/UPPER
LEVEL VORT MAX...CURRENTLY CROSSING SRN ID...WILL ROTATE THROUGH THE
LARGE SCALE TROUGH WITH A 60-90M 500MB HEIGHT FALL CENTER SPREADING
ACROSS THE DAKOTAS AND WRN MN THROUGH THIS EVENING. AS THIS
OCCURS...A SERIES OF WEAK FRONTAL WAVES WILL RIPPLE ENEWD ALONG
INTENSIFYING COLD FRONT AND ACT TO SHIFT THE BOUNDARY GRADUALLY
EWD/SEWD INTO INCREASINGLY WARM/MOIST AIRMASS FROM THE CNTRL PLAINS
TO THE UPPER MS VALLEY THROUGH EARLY TUESDAY.

...CNTRL PLAINS TO UPPER MS VALLEY...
MODELS ARE IN VERY GOOD AGREEMENT THAT STRONG WARM CONVEYOR BELT AND
DIURNAL HEATING AHEAD OF THE STRENGTHENING FRONT WILL ALLOW FOR AT
LEAST MODERATE INSTABILITY /MLCAPE 1000-1800 J/KG/ TO DEVELOP IN AN
AXIS FROM NEB TO MN THIS AFTERNOON. WARM SECTOR AIRMASS IS EXPECTED
TO REMAIN MOSTLY CAPPED INTO MID-AFTERNOON GIVEN A DEEP LAYER OF
WARM AIR JUST ABOVE THE BOUNDARY LAYER. STRONG CAP WILL AID IN
EFFICIENT MOISTURE TRANSPORT WITHIN THE LOW LEVEL JET AXIS WITH LOW
TO MID 60S F SURFACE DEWPOINTS SPREADING NWD BENEATH STEEP MID LEVEL
LAPSE RATES AROUND 8C/KM.

WEAKER CAP AND SOMEWHAT STRONGER FORCING ASSOCIATED WITH DPVA AND
FRONTAL CIRCULATION SHOULD PROMOTE INITIAL SURFACE-BASED TSTM
DEVELOPMENT ACROSS WRN AND NRN MN BY MID TO LATE AFTERNOON. THIS
SHOULD BE FOLLOWED OVER THE NEXT FEW HOURS BY ADDITIONAL TSTM
DEVELOPMENT SWWD ALONG INSTABILITY AXIS IMMEDIATELY AHEAD OF THE
FRONTAL BOUNDARY AS SURFACE HEATING AND MIXING ACT TO OVERCOME
CONVECTIVE INHIBITION.

ACROSS MN...40KT SLY LOW LEVEL FLOW TOPPED BY INCREASING SWLY MID
LEVEL FLOW OF 50KT WILL RESULT STRONG DIRECTIONAL AND SPEED SHEAR
SUPPORTIVE OF SUPERCELLS. SHEAR VECTORS ALSO REMAIN ORIENTED
SOMEWHAT PERPENDICULAR TO THE SURFACE FRONT SUGGESTING ACTIVITY
SHOULD REMAIN CELLULAR...PERHAPS EVOLVING INTO A BROKEN CONVECTIVE
LINE WITH TIME. WHILE NEAR SURFACE FLOW REMAINS PRIMARILY
VEERED...AND BOUNDARY LAYER MIXING RATIOS ARE RELATIVELY LOW...A
TORNADO OR TWO COULD OCCUR INVOF FRONTAL WAVES WHERE LOCALLY BACKED
LOW LEVEL FLOW RESULTS IN GREATER SRH AND STORM INFLOW THROUGH
EVENING. PRIMARY THREATS...HOWEVER...ARE EXPECTED TO BE HAIL AND
DAMAGING WINDS WITH STORMS SPREADING ENEWD ACROSS MUCH OF WRN AND
CNTRL MN THROUGH THE EVENING.

FARTHER SOUTH AND WEST...TSTMS SHOULD ERUPT NEAR THE FRONT AS
CONVECTIVE INHIBITION IS ELIMINATED THROUGH WEAK ASCENT AND HEATING.
EFFECTIVE SHEAR IS WEAKER ACROSS AREAS FROM SWRN MN INTO NEB ALONG
THE SRN EDGE OF THE STRONGER MID LEVEL FLOW. HOWEVER... FCST
THERMODYNAMIC PROFILES EXHIBIT DEEPLY MIXED BOUNDARY LAYER AIRMASS
SUPPORTIVE OF DAMAGING OUTFLOW WINDS...AND STEEP MID LEVEL LAPSE
RATES FAVORING LARGE HAIL. IT IS POSSIBLE THAT OUTFLOW DOMINANT
ACTIVITY AND COLD POOL DEVELOPMENT...COUPLED WITH LIFT ALONG THE
ADVANCING FRONT...WILL SUPPORT THE EVOLUTION OF A SMALL MCS WITH
POTENTIAL FOR SEVERE WIND AND HAIL DEVELOPING EWD/SEWD ACROSS THE MO
RIVER VALLEY THROUGH LATE TONIGHT.

..CARBIN/TAYLOR.. 09/13/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.