ZCZC SPCSWODY1 ALL
ACUS01 KWNS 211638
SPC AC 211638

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT THU AUG 21 2003

VALID 211630Z - 221200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 N
CLE 20 SW FDY 45 NNW EVV 30 WNW MDH 35 SSW TBN 20 ENE BVO 25 NW PNC
25 SW RSL MHK 40 WSW OTM 30 NNW MLI 30 ESE MSN 10 E GRB 10 ENE GRB
35 ENE AUW 35 NW IMT 120 NNW ANJ

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 SSE DRT 40 WNW AUS
10 NNW ACT 20 W DUA 25 NNW FSI 25 NW PVW 40 NNW HOB 15 SSE ELP
...CONT... 40 S ONP 20 S DLS 35 SW S80 15 WSW BTM 55 N BIL 15 NNW
GDV 60 S Y22 45 SW RAP 35 S BFF 15 WSW MCK 40 WSW LNK 40 NW LWD 10
ENE LNR 40 WSW RHI 135 NE CMX ...CONT... 40 SSE AUG 15 WSW BML 15
NNW HGR 25 W RIC 25 N HSE

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE UPR GRT LKS...AND OVER
PARTS OF THE CNTRL PLNS/MID MS VLY....

...SYNOPSIS...
RIDGE WILL HOLD FIRM OVER THE CNTRL RCKYS AS POTENT SHORTWAVE SYSTEM
CONTINUES E ACROSS THE UPR GRT LKS INTO WRN QUEBEC.  ELSEWHERE...
SATELLITE/RAOB DATA CONTINUE TO SHOW WEAK UPPER DISTURBANCES MOVING
W ALONG THE CNTRL GULF CST...SLOWLY E/SE ACROSS KS/OK...AND N ACROSS
BOTH SRN NV AND NE CA.

AT LOWER LEVELS...COLD FRONT ASSOCIATED WITH GRT LKS SYSTEM...NOW
EXTENDING FROM WRN UPR MI/N CNTRL WI THROUGH S CNTRL IA TO WRN KS 
...SHOULD BECOME MORE SHARPLY DEFINED WITH TIME AND REACH A SE MI/
NRN MO/SW KS LINE BY EARLY THIS EVENING.

...WI/MI/IND/IL...
LEAD IMPULSE ASSOCIATED WITH GRT LKS SHORTWAVE COMPLEX WILL BE
EXITING ERN LWR MI IN THE NEXT FEW HOURS. CONVECTION WITH THIS
FEATURE HAS LEFT A WEAK OUTFLOW BOUNDARY ORIENTED ROUGHLY W/E ACROSS
CNTRL LWR MI.  THIS BOUNDARY SHOULD WEAKEN AND LIFT SLOWLY NWD INTO
WEAKEN OVER NRN LWR MI LATER TODAY.  IT MAY SERVE AS A FOCUS FOR NEW
STORM DEVELOPMENT AS SURFACE HEATING AND APPROACH OF STRONGER
UPSTREAM DISTURBANCE...NOW ENTERING CNTRL WI...FURTHER DESTABILIZE
REGION.

AREA RAOB AND VWP DATA SHOW AMPLE SHEAR ALREADY PRESENT TO SUPPORT 
ORGANIZED STORMS OVER THE UPR GRT LKS...AND DEEP SHEAR SHOULD
INCREASE AS 50 KT MID LEVEL SPEED MAX ASSOCIATED WITH WI IMPULSE
OVERSPREADS REGION.  COUPLED WITH RELATIVELY STEEP LOW TO MID LEVEL
LAPSE RATES AND RESPECTABLE CONVECTIVE DOWNDRAFT POTENTIAL...SETUP
ALONG COLD FRONT SHOULD BECOME FAVORABLE FOR BOTH ISOLATED
SUPERCELLS...AND BANDS/CLUSTERS OF FORWARD- PROPAGATING STORMS WITH
HIGH WIND...FROM NE WI/ERN UPR MI INTO NRN LWR MI.  OTHER ACTIVITY
/INCLUDING SUPERCELLS/ MAY FORM FARTHER S OVER SE WI AND NRN IL AS
HEATING/LARGE SCALE ASCENT OCCUR ALONG INTENSIFYING COLD FRONT LATER
THIS AFTERNOON.  SOME OF THE LATTER ACTIVITY MAY MOVE INTO SRN LWR
MI AND NRN IND BY THIS EVENING...AND PERSIST INTO THE NIGHT.

WHILE LARGELY UNIDIRECTIONAL WIND PROFILES AND GOOD POTENTIAL FOR
COLD CONVECTIVE DOWNDRAFT DEVELOPMENT SHOULD TEND TO LIMIT THREAT
FOR TORNADOES...GIVEN STRENGTH OF SHEAR AND DEGREE OF INSTABILITY
/100 MB ML CAPE TO 2500 J/KG/...PATTERN COULD YIELD A TORNADO OR
TWO...ESPECIALLY WITH ANY STORMS INTERACTING WITH W/E ORIENTED
OUTFLOW AND/OR LAKE BREEZE BOUNDARIES.

...CNTRL PLNS...
STRONG HEATING OF DEEPLY MIXED ENVIRONMENT...GLANCING INFLUENCE OF
GRT LKS UPPER TROUGH AND FRONTAL CONVERGENCE LIKELY TO YIELD ANOTHER
ROUND OF ORGANIZED MICROBURST-PRODUCING STORMS ACROSS NRN MO AND
CNTRL/ERN KS.  THIS ACTIVITY SHOULD WEAKEN AFTER SUNSET.

...LWR MS VLY/WRN GULF CST...
STRONG HEATING WILL ALSO OCCUR AHEAD OF WWD-MOVING UPPER DISTURBANCE
OVER LA AND ASSOCIATED SHEAR AXIS EXTENDING N INTO FAR WRN MS. 
COUPLED WITH INCREASING NELY FLOW AT MID LEVELS... ENVIRONMENT MAY
BECOME SUPPORTIVE OF SWWD-MOVING CLUSTERS OF STRONG STORMS WITH
LOCALLY-DAMAGING WIND OVER SRN AR/NRN LA AND E TX LATER TODAY/EARLY
TONIGHT.

...SW U.S...
LOW TO MID LEVEL MOISTURE HAS BECOME WIDESPREAD FROM THE SWRN
DESERTS NWD ALONG THE SIERRA INTO THE NRN GRT BASIN OVER THE PAST
TWO DAYS...WITH AXIS OF COOLEST MID LEVEL TEMPERATURES EXTENDING
FROM AZ INTO NV.  CLOUDS WILL INHIBIT HEATING NEAR UPPER DISTURBANCE
OVER NE CA/NRN NV...BUT HEATING SHOULD OCCUR AHEAD OF IMPULSE OVER
SRN NV.  THIS MAY YIELD A CLUSTER OR TWO OF STRONG STORMS WITH
LOCALLY DAMAGING WINDS LATER TODAY.

FARTHER S...STRONG WINDS MAY ALSO OCCUR OVER SRN/WRN AZ LATER TODAY
AS HEATING CONTINUES AHEAD OF CONVECTIVE SYSTEM FORWARD-PROPAGATING
NWD FROM SONORA.

..CORFIDI/CROSBIE.. 08/21/2003

...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.

$$