ACUS KMKC 211630
SWODY1
KMKC AC 211630    
    
STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWBC.

VALID 211630Z - 221200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
50 NW GCK 45 N LAA 45 W AKO 35 NNE CYS 35 NNW BFF 30 NE AIA
30 WNW BBW 40 S HSI 25 NE RSL 35 SW RSL 50 NW GCK.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 75 S GBN 10 SSW FLG
10 ESE U17 40 NNW GJT 40 S RWL 25 WNW DGW 35 E SHR 30 ENE 4BQ
40 SE Y22 40 ENE ABR 10 SSW BRD 40 NE ELO ...CONT... 40 SE ANJ
15 SSE HTL 10 SSE AZO HUF 10 NE MVN 40 WNW MDH 25 NNW UNO
10 SE UMN 35 WNW END 65 ENE AMA 30 SE CVS ROW 10 WSW ELP.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SSE VCT
40 SSW CLL 55 NE CLL 25 ENE GGG 30 SE ELD 40 WNW JAN 10 WSW LUL
65 NE MOB 25 ESE TOI 25 E CSG 10 ESE MCN 60 W SAV 15 SSE SAV.

...SEVERE THUNDERSTORM FORECAST DISCUSSION...

SATELLITE IMAGERY SHOWS VIGOROUS UPPER SHORT WAVE TROUGH LIFTING
NEWD INTO NWRN ONTARIO AS UPPER RIDGE PERSISTS OVER THE SRN PLAINS.
WATER VAPOR LOOP ALSO SUGGESTS RIDGE IS SLOWLY BUILDING NWWD ACROSS
THE FOUR CORNERS AREA IN THE WAKE OF THE ONTARIO TROUGH.  AT THE
SURFACE...NRN PART OF THE COLD FRONT FROM MN ACROSS ERN NEB THEN
WSWWD INTO THE CENTRAL HIGH PLAINS WILL CONTINUE EWD ACROSS THE
UPPER MS VALLEY AND WRN GREAT LAKES...WHILE THE HIGH PLAINS PART IS
EXPECTED TO LIFT NWD AS A WARM FRONT TONIGHT.

...CENTRAL PLAINS...
12Z ETA AND RUC INDICATE SURFACE RIDGE AXIS OVER THE NRN HIGH
PLAINS WILL MOVE EWD TODAY WITH SELY LOW LEVEL WINDS DEVELOPING
OVER THE CENTRAL HIGH PLAINS REGION BY LATE THIS AFTERNOON.  LOW
LEVEL MOISTURE WITH SURFACE DEW POINTS IN THE 50S/LOW 60S IS
EXPECTED TO REMAIN FROM WRN KS/ERN CO INTO WRN NEB...POSSIBLY
INCREASING INTO EXTREME SERN WY BY EVENING.  STEEP MID LEVEL LAPSE
RATES AROUND 8C/KM WILL CONTRIBUTE TO UNSTABLE ENVIRONMENT WITH
SBCAPE OF 1500-2500 J/KG.  AIR MASS MAY REMAIN CAPPED THROUGH MUCH
OF THE AFTERNOON...BUT CONTINUED HEATING AND DEVELOPMENT OF UPSLOPE
FLOW WILL RESULT IN INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT NEAR THE ERN SLOPES OF THE ROCKIES.  WINDS ARE FORECAST
TO VEER AND INCREASE WITH HEIGHT...PROVIDING SUFFICIENT SHEAR FOR
ORGANIZED MULTICELLS AND POSSIBLY ISOLATED SUPERCELL STORMS. 
FORECAST SOUNDINGS EXHIBIT DEEP SURFACE-BASED MIXED LAYERS WHICH
WILL ENHANCE THREAT FOR STRONG/DAMAGING WIND GUSTS ALONG WITH LARGE
HAIL.  STORMS ARE FORECAST TO SPREAD/DEVELOP EWD ACROSS THE PLAINS
AND MO RIVER VALLEY TONIGHT...POSSIBLY REACHING THE MIDDLE MS
VALLEY BY THE END OF THE PERIOD.  PRIMARY SEVERE THREAT IS EXPECTED
TO DIMINISH AFTER 04-05Z ALTHOUGH MARGINAL HAIL POTENTIAL MAY
CONTINUE THROUGH THE OVERNIGHT HOURS.

...SERN TX/SRN LA/MS COAST...
WATER VAPOR IMAGERY SHOWS MID/UPPER LEVEL DRY INTRUSION OVER AL AND
ERN MS BEGINNING TO TURN SWWD TOWARD THE LOWER MS VALLEY.  AHEAD OF
THIS FEATURE...12Z SOUNDINGS SHOW MODERATELY STEEP LOW LEVEL
LAPSE RATES AND PRESENCE OF DRY AIR ABOVE THE VERY MOIST SURFACE
LAYER...SUGGESTING POTENTIAL FOR MICROBURSTS THIS AFTERNOON AND
EVENING.  25-30 KT ENELY MID LEVEL WINDS EVIDENT IN
12Z RAOBS ARE CONTINUING ACCORDING TO VAD PROFILES.  THIS WILL
ALLOW ANY PERSISTENT STORMS TO SPREAD WWD ALONG THE CENTRAL GULF
COAST REGION.  SOME HAIL IS ALSO POSSIBLE WITH STRONGER
CELLS...HOWEVER NATURE OF SEVERE THREAT APPEARS TOO BRIEF/LOCALIZED
TO WARRANT A SLIGHT RISK ATTM.

...SERN AZ...
12Z SOUNDINGS AT TUS AND PHX EXHIBITED INVERTED-V CHARACTERISTICS
WITH DEEP MIXED LAYERS BENEATH MID LEVEL MOISTURE.  SERIES OF WEAK
PERTURBATIONS IN SELY MID LEVEL FLOW ARE APPARENT IN WATER VAPOR
IMAGERY MOVING FROM NRN MEX TOWARD SRN AZ...SUGGESTING THAT
CONVECTION WILL REDEVELOP OVER THE HIGHER TERRAIN OF SERN AZ THIS
AFTERNOON AND EVENING.  ISOLATED MICROBURSTS WILL BE POSSIBLE WITH
STORMS AS THEY PROPAGATE OFF THE MOUNTAINS.

..WEISS.. 08/21/00

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 2000Z