ZCZC SPCSWODY1 ALL COR
ACUS01 KWNS 211309
SPC AC 211308 COR...CORRECTED GRAPHICS

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.

VALID 211300Z - 221200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
20 W GRI 25 ENE SLN 30 SE ICT 20 SSE P28 30 ESE LAA 30 N AKO
20 SE CDR 25 S PHP 20 W GRI.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
25 WNW EFK 30 SSW ALB 25 SE MRB 0A8 15 S JAN 20 ENE ELD 45 SSE HRO
35 NW ARG 25 SE SBN 25 SSE DTW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 55 ESE YUM
60 NNW GBN 30 WNW SGU 60 WNW P38 35 E BIH 60 NW NID 20 NE SAC
55 NNW UKI 35 E 4BK 25 SSE EUG 30 W RDM 40 S RDM 45 NE 4LW
15 SE OWY 35 SSW BYI 30 WNW BPI 30 NE RIW 40 SW GCC 15 NNE 4BQ
55 NNE GGW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 S WAL 15 WSW RIC
35 SSW SOP 15 SSW CRE.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 E PSX 45 NW LFK
45 E DAL 35 W SPS 45 S CVS 20 S ALM 40 SE DMN.

...SYNOPSIS...
UPPER FLOW PATTERN IS FORECAST TO AMPLIFY THIS PERIOD AS RIDGE
REMAINS OVER THE ROCKIES AND ERN TROUGH STRENGTHENS.  AMPLIFICATION
OF THIS TROUGH IS EXPECTED TO OCCUR AS SEVERAL VORTICITY MAXIMA
DROP SEWD OUT OF CANADA IN FAST NWLY FLOW ON WRN PERIPHERY OF MAIN
TROUGH.  

SURFACE BAROCLINIC ZONE EXTENDS ATTM FROM THE ST. LAWRENCE VALLEY
SWWD INTO A LOW APPROACHING NRN LK MI...AND THEN ARCS SWWD ACROSS
IL / MO INTO KS / OK.  ERN PORTION OF THIS BOUNDARY IS FORECAST TO
LINGER INVOF THE SERN CANADA / NORTHEAST U.S. BORDER THROUGH THE
PERIOD.  HOWEVER...SURFACE LOW OVER THE UPPER GREAT LAKES REGION IS
FORECAST TO MOVE EWD WITH TIME INTO THE LOWER GREAT LAKES REGION AS
UPPER TROUGH DIGS...ALLOWING BAROCLINIC ZONE TO MOVE SEWD TO THE OH
VALLEY / SWD TO THE RED RIVER VALLEY BY THE END OF THE PERIOD.

...MID MS / OH VALLEYS INTO THE LOWER GREAT LAKES REGION...
LARGE MCS / BOW ECHO CONTINUES MOVING ACROSS THE MIDDLE AND LOWER
OH VALLEY ATTM AHEAD OF MAIN SURFACE FRONT EXTENDING FROM NERN IL
SWWD INTO CENTRAL MO.  INSTABILITY WEAKENS WITH EWD EXTENT UP THE
OH VALLEY...SO SOME WEAKENING OF CONVECTION IS POSSIBLE OVER THE
NEXT FEW HOURS.  HOWEVER...WELL-ORGANIZED COLD POOL SUGGESTS THAT
STORMS AND ASSOCIATED DAMAGING WIND THREAT WILL CONTINUE.  AS
DAYTIME HEATING COMMENCES THROUGH THIS AFTERNOON...AIRMASS AHEAD OF
ONGOING CONVECTION SHOULD DESTABILIZE.  THIS COMBINED WITH
FAVORABLY STRONG DEEP-LAYER WINDS SHOULD ALLOW A RE-INTENSIFICATION
OF CONVECTION ACROSS NY / PA...WITH ASSOCIATED THREAT FOR DAMAGING
WINDS AND SOME HAIL EXPECTED TO INCREASE AS WELL.

AIRMASS IS MORE UNSTABLE SOUTH OF THE OH RIVER INTO THE TN
VALLEY...SO EXPECT SRN PORTIONS OF THIS MCS TO CONTINUE DEVELOPING
SEWD ACROSS THE OH AND INTO THE TN VALLEYS.  ALTHOUGH STRONGEST
DEEP-LAYER WIND FIELD EXISTS N OF THE OH VALLEY ATTM...FLOW SHOULD
INCREASE SWD AS UPPER TROUGH DIGS.  THIS SUGGESTS THAT THE THREAT
FOR DAMAGING WINDS / HAIL WILL PERSIST / INCREASE ACROSS THIS AREA
THROUGH THE AFTERNOON.

ADDITIONAL CONVECTIVE DEVELOPMENT MAY ALSO OCCUR ALONG MAIN COLD
FRONT / BEHIND ONGOING MCS WHERE MOIST AIRMASS SHOULD DESTABILIZE
WITH DAYTIME HEATING / AHEAD OF NEXT FEATURE ALOFT APPROACHING FROM
THE NW.  DAMAGING WINDS AND HAIL WILL BE POSSIBLE WITH THESE STORMS
GIVEN FAVORABLE DEEP-LAYER WIND FIELD.

STORMS SHOULD CONTINUE AHEAD OF SURFACE BOUNDARY THROUGH THE
PERIOD...WITH SEVERE THREAT EXTENDING AS FAR E AS THE APPALACHIAN
CREST BY THE END OF THE PERIOD.

...NRN HIGH PLAINS SEWD INTO THE CENTRAL PLAINS...
ONGOING STORMS ACROSS NWRN NEB SHOULD INCREASE THROUGH THE DAY AS
AIRMASS HEATS / DESTABILIZES INVOF NNW-SSE BAROCLINIC ZONE OVER
THIS REGION.  WITH FAIRLY STRONG NWLY FLOW ALOFT ABOVE SELY LOW-
LEVEL FLOW...DEEP-LAYER SHEAR WILL BE FAVORABLE FOR SUPERCELLS...
WITH LARGE HAIL AND LOCALLY DAMAGING WINDS EXPECTED.  OVERNIGHT...
STORMS MAY MERGE INTO AN MCS AND MOVE SEWD ACROSS KS...ALONG WITH
DAMAGING WIND / HAIL THREAT.

...AZ...
STORMS SHOULD AGAIN DEVELOP ACROSS THE HIGHER TERRAIN OF SERN AZ
AND THE MOGOLLON RIM...AND THEN MOVE WSWWD INTO S CENTRAL AZ IN
ENELY FLOW TO THE SOUTH OF UPPER RIDGE.  WITH MARGINAL INSTABILITY
EXPECTED ABOVE DEEP / WELL-MIXED BOUNDARY LAYER...A LIMITED THREAT
FOR LOCALLY DAMAGING WINDS / HAIL WILL EXIST.

..GOSS.. 07/21/03

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