SPC Day 1 Thunderstorm Outlook Issued 13Z 20030825


ZCZC SPCSWODY1 ALL
ACUS01 KWNS 251254
SPC AC 251254

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0754 AM CDT MON AUG 25 2003

VALID 251300Z - 261200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SE
DTW 15 NW FDY 30 SSE CGX 30 WSW DBQ 20 WNW MHE 40 WNW PIR 30 ESE Y22
30 ENE BIS 65 NNE DVL

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 WNW CZZ 20 E RAL
20 S PMD 35 ESE FAT 55 NE MER 40 NW EKO 30 S MLD 40 NNE VEL 35 NNW
LAR 35 NNE REJ 65 NNW MOT ...CONT... 25 W ERI 25 SE DUJ 15 ENE MRB
SHD 20 ENE CRW 45 ENE LUK 15 N DNV 35 NW UIN 40 N SZL 40 N SGF 35 SE
HRO 35 WSW MEM 30 E TUP 10 N RMG 40 SW HSS 35 NW HKY 25 SE GSO 25 SW
SOP 20 W FLO 20 SSW CRE

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 ESE LNK 35 ESE GRI
35 SSW EAR 35 SE LAA 30 E TCC 55 SSE CVS 30 SSE LBB 30 S CDS 20 SSE
END 30 W EMP 25 ESE LNK

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 NE 4OM 55 NW EAT
10 SW HQM

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ERN DAKOTAS ACROSS THE
UPPER GREAT LAKES REGION...

...SYNOPSIS...
FAST ZONAL FLOW ACROSS THE NRN CONUS ATTM WILL AMPLIFY SOMEWHAT THIS
PERIOD AS UPPER LOW NOW OFF THE BRITISH COLUMBIA COAST MOVES EWD AND
SECOND / LOW-AMPLITUDE SHORT-WAVE TROUGH MOVES ESEWD ACROSS THE
CANADIAN PRAIRIE PROVINCES.  THIS SECOND FEATURE AND ASSOCIATED
MID-LEVEL JET STREAK WILL INFLUENCE THE SEVERE CONVECTIVE FORECAST
ACROSS THE N CENTRAL CONUS.

AT THE SURFACE...CONVECTIVELY-REINFORCED BAROCLINIC ZONE LYING
ROUGHLY W-E FROM THE DAKOTAS EWD ACROSS MN / WI SHOULD LIFT SLOWLY
NWD AS A WARM FRONT AHEAD OF COLD FRONT FORECAST TO MOVE SEWD ACROSS
THE NRN PLAINS.  THIS FRONT -- ASSOCIATED WITH AFOREMENTIONED
SHORT-WAVE TROUGH / JET MAX -- IS EXPECTED TO EXTEND FROM THE UPPER
GREAT LAKES SWWD ACROSS IA INTO SRN NEB / NRN KS BY THE END OF THE
PERIOD.

...NRN PLAINS EWD INTO THE UPPER GREAT LAKES REGION...
COMPLICATED FORECAST THIS PERIOD WITH ONGOING PRECIPITATION AND
LATEST RAOBS / SURFACE DATA INDICATING LESS POTENTIAL FOR
DESTABILIZATION ACROSS THE REGION THAN MODEL FORECASTS WOULD
SUGGEST.

STORMS CONTINUE ATTM INVOF SURFACE BOUNDARY ACROSS SERN MN / SRN
WI...AS WELL AS ACROSS ERN ND INVOF WEAK IMPULSE AHEAD OF STRONGER
UPPER TROUGH / JET MAX.  ALTHOUGH SOME DECREASE IN CONVECTION IS
POSSIBLE OVER THE NEXT SEVERAL HOURS...SCATTERED STORMS SHOULD
CONTINUE INTO THE AFTERNOON.

ALTHOUGH DEGREE OF DESTABILIZATION REMAINS A QUESTION...STORMS
SHOULD INCREASE / REDEVELOP DURING THE AFTERNOON INVOF W-E
BAROCLINIC ZONE ACROSS THE SRN GREAT LAKES REGION...AND ALSO AHEAD
OF COLD FRONT WHICH SHOULD BE MOVING SEWD ACROSS THE DAKOTAS / NWRN
MN.  WITH BELT OF MODERATE TO STRONG MID-LEVEL FLOW ACROSS THIS
REGION...STORMS SHOULD ORGANIZE / BECOME SEVERE...ALTHOUGH
CONVECTIVE MODE REMAINS DIFFICULT TO DETERMINE ATTM.  STRONGER
LINEAR FORCING ALONG SEWD-MOVING COLD FRONT SUGGESTS THAT STORMS
SHOULD BE MAINLY LINEAR WITH BOWING STRUCTURES ACROSS THE NRN GREAT
LAKES REGION...PARTICULARLY INTO THE EVENING / OVERNIGHT. 
MEANWHILE... WEAKER FORCING FURTHER SOUTH MAY SUPPORT MORE ISOLATED
/ SUPERCELL STORMS.  LARGE HAIL AND DAMAGING WINDS WILL LIKELY BE
THE MAIN SEVERE THREATS...WITH GREATER HAIL THREAT ACROSS SRN
PORTIONS OF THE RISK AREA AND GREATER / POTENTIALLY SIGNIFICANT WIND
THREAT ACROSS NRN MN / NRN WI / UPPER MI.  

OVERNIGHT...STORMS SHOULD SPREAD EWD ACROSS THE REGION TOWARD SRN
ONTARIO AS SHORT-WAVE TROUGH MOVES RAPIDLY EWD.

..GOSS.. 08/25/2003

...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.

$$