[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 200516
SWODY1
SPC AC 200514

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1214 AM CDT TUE JUL 20 2004

VALID 201200Z - 211200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 NNW
ELO 50 SSE DLH MSN 40 NW CGX 30 NE BMI 35 E UIN 20 NW IRK 30 NNW OMA
30 NW YKN 50 NNW ABR 70 N DVL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 SE FHU 45 WNW SAD
15 WSW FLG 30 W P38 65 N BIH 35 SSE NFL 20 SE WMC 85 WNW OWY 55 W
BKE 25 ESE GEG 50 NE 63S ...CONT... 35 NW CTY 40 SSW AGS 30 NNW SOP
20 WNW ROA 30 SE JKL 45 NNW CSV 10 NE HOP 20 N ARG 25 NNW HRO 40 SSW
OJC 20 NNE EMP 25 WNW HUT 40 W P28 50 E LBB P07.

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE NRN
PLAINS/UPPER MS VALLEY INTO THE UPPER MIDWEST...

...SYNOPSIS...
DOMINANT UPPER RIDGE OVER THE DESERT SW INTO THE NRN HIGH PLAINS
WILL FLATTEN SIGNIFICANTLY THROUGH THE PERIOD AS BROAD CYCLONIC FLOW
REGIME IS ESTABLISHED ACROSS SRN CANADA. SHORTWAVE TROUGH OVER WRN
SD WILL TRANSLATE EWD INTO MN LATER TODAY WITH STRONGER UPSTREAM
DISTURBANCE /NOW OVER THE NRN ROCKIES/ SHIFTING EWD ACROSS THE NRN
HIGH PLAINS AND INTO THE DAKOTAS OVERNIGHT.

AT THE SURFACE...COLD FRONT ATTENDANT TO THE WRN SD SHORTWAVE TROUGH
WILL CONCURRENTLY PUSH EWD AND WILL LIKELY EXTEND FROM LOW PRESSURE
OVER ERN SASKATCHEWAN/MANITOBA SWD TO A SECONDARY LOW OVER SERN
SD/NERN NEB AND THEN SWWD INTO NERN CO. FRONTAL BOUNDARY NOW STALLED
ACROSS NERN NEB INTO NRN IA WILL RETREAT NWD AS A WARM FRONT IN
RESPONSE TO FALLING PRESSURES TO THE W.

...NRN PLAINS/UPPER MS VALLEY INTO THE UPPER MIDWEST...
CLUSTERS OF STORMS ARE LIKELY TO BE ONGOING INITIALLY OVER PORTIONS
OF THE CNTRL AND ERN DAKOTAS WITHIN ZONE OF ASCENT AHEAD OF
EWD-MIGRATING SHORTWAVE TROUGH. PERSISTENT CLOUD/PRECIPITATION
SHIELD MAY SLOW DESTABILIZATION OF IMMEDIATE DOWNSTREAM AIRMASS
THROUGH THE DAY...HOWEVER INFLUX OF VERY MOIST BOUNDARY-LAYER ACROSS
IA WITH DEWPOINTS OF 70-75F WILL OCCUR WITH ESTABLISHMENT OF
SLY/SWLY LLJ. EVAPOTRANSPIRATION SHOULD OFFSET DIURNAL
MIXING...MAINTAINING THIS MOISTURE ACROSS THE WARM SECTOR THROUGH
THE DAY. WHEN COUPLED WITH DAYTIME HEATING AND STEEP MID-LEVEL LAPSE
RATES...EXPECT AIRMASS S OF RETREATING WARM FRONT TO BECOME
EXTREMELY UNSTABLE WITH MLCAPES APPROACHING 3000-3500 J/KG.

INTENSIFICATION OF ONGOING STORMS AND DEVELOPMENT OF ADDITIONAL DEEP
CONVECTION IS ANTICIPATED BY AFTERNOON OVER ERN SD INTO WRN MN AS
FORCING FOR ASCENT AHEAD OF SHORTWAVE TROUGH ENCOUNTERS
DESTABILIZING AIRMASS. MODERATELY STRONG DEEP-LAYER SHEAR OF
30-40KTS SHOULD SUPPORT SUPERCELLS /GIVEN THE DEGREE OF INSTABILITY/
CAPABLE OF LARGE HAIL AND DAMAGING WINDS. GREATEST POTENTIAL FOR
ISOLATED TORNADOES WILL EXIST INVOF RETREATING BOUNDARY WHERE BACKED
NEAR-SURFACE WINDS WILL RESULT IN LOCALLY ENHANCED LOW-LEVEL SHEAR. 
SWD DEVELOPMENT OF STORMS WILL LIKELY BE DICTATED BY PROGRESSIVELY
STRONGER CAP WHICH IS FORECAST ACROSS IA.

ADDITIONAL STRONG TO SEVERE STORM CLUSTERS ARE ANTICIPATED ALONG
FRONT OVER PORTIONS OF ERN ND INTO W-CNTRL INTO NWRN MN. THOUGH
INSTABILITY WILL BE WEAKER THAN POINTS TO THE S...SUFFICIENTLY
STRONG LARGE-SCALE FORCING AND DEEP-LAYER SHEAR WILL EXIST TO
SUPPORT A WIND/HAIL THREAT WITH THE MOST INTENSE ACTIVITY.

...NRN ROCKIES INTO NRN HIGH PLAINS...
POTENTIAL WILL EXIST FOR ISOLATED SEVERE STORMS LATER TODAY ALONG
SECONDARY COLD FRONT/PRESSURE TROUGH AND/OR FAVORED TERRAIN AS
FORCING FOR ASCENT ALONG SRN EDGE OF SHORTWAVE TROUGH OVERSPREADS
REGION. THOUGH VEERED LOW-LEVEL PATTERN IS EXPECTED TO PERSIST
THROUGH THE DAY...PRESENCE OF STEEP LOW TO MID-LEVEL LAPSE RATES 
WILL LARGELY CONTRIBUTE TO WEAK TO MODERATE INSTABILITY WITH MLCAPES
OF 500-1000 J/KG. 40-50KT MID-LEVEL JET STREAK ACCOMPANYING
SHORTWAVE TROUGH WILL RESULT IS SUFFICIENT VERTICAL SHEAR FOR
ORGANIZED STORMS CAPABLE OF ISOLATED LARGE HAIL/DAMAGING WINDS.

..MEAD/CROSBIE.. 07/20/2004

...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.