Severe Thunderstorm Warning 123, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1211 PM CDT WED AUG 25 2004

.DISCUSSION...
DECAYING MCS THAT MOVED OUT OF N CENTRAL MO MOVED THROUGH SE HALF OF
CWA AND HAS ABOUT EXITED CWA AT NOON. CLOUDS AND RAIN HELD TEMPS
IN 60S TO LOWER 70S. SATELLITE IMAGERY SHOWS SOME THINNING OF CLOUD
COVER OVER CENTRAL IA AND WILL HAVE TO WATCH FOR AMOUNT OF RECOVERY
AHEAD OF CURRENT SEVERE COMPLEX OVER NE MO AND SW IA. THIS WAS
ASSOCIATED WITH WELL DEFINED SHORTWAVE IN SW IA MOVING NORTHEAST AND
WILL TAKE AIM AT SOUTHERN HALF CWA BY MID AFTERNOON. THINK BEST
SEVERE THREAT WILL BE FAR SOUTH CLOSER TO MOST UNSTABLE AIRMASS
SOUTH OF SYNOPTIC FRONT IN NORTHERN MO THAT IS BEING REINFORCED BY
DIFFERENTIAL HEATING.

HAVE UPDATED FORECAST PRODUCTS FOR LOWER MAX TEMPS AND LOWERED
POPS...ESPECIALLY ACROSS NORTH.
&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

SHEETS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
552 AM CDT WED AUG 25 2004

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-261000-
BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO-
CLINTON IA-DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL-
HENDERSON IL-HENRY IA-HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA-
JO DAVIESS IL-JOHNSON IA-JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA-
MCDONOUGH IL-MERCER IL-MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL-
SCOTLAND MO-SCOTT IA-STEPHENSON IL-VAN BUREN IA-WARREN IL-
WASHINGTON IA-WHITESIDE IL-
552 AM CDT WED AUG 25 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST...EAST
CENTRAL...AND SOUTHEAST IOWA...NORTHWEST...NORTH CENTRAL...AND WEST
CENTRAL ILLINOIS...AND NORTHEAST MISSOURI.

.DAY ONE...TODAY AND TONIGHT

RAIN WITH EMBEDDED THUNDERSTORMS WILL END AROUND MID MORNING.
LOCALLY HEAVY RAIN IS POSSIBLE ALONG AND SOUTH OF HIGHWAY 34.

THIS AFTERNOON AND EVENING...MORE THUNDERSTORMS ARE EXPECTED TO
DEVELOP. IF SUFFICIENT INSTABILITY AND SHEAR DEVELOPS...SEVERE
STORMS WOULD BE POSSIBLE. SHOULD THE SEVERE STORMS DEVELOP...HAIL UP
TO 1 INCH WITH WINDS OF 60 TO 70 MPH COULD BE EXPECTED.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH NEXT WEDNESDAY

AN ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE REMAINDER OF THE
WEEK.

ON THURSDAY...LINGERING SHOWERS OR POSSIBLY A THUNDERSTORM IS
EXPECTED THROUGH MID MORNING EAST OF A FREEPORT TO MACOMB LINE.

HIGH HEAT AND HUMIDITY IS THEN EXPECTED THROUGH THURSDAY AFTERNOON
WITH TEMPERATURES IN THE UPPER 80S TO LOWER 90S. HEAT INDICES ARE
EXPECTED TO RANGE FROM THE UPPER 90S TO NEAR 105.

LATE THURSDAY AFTERNOON INTO THURSDAY NIGHT A POTENTIALLY
DANGEROUS SITUATION IS DEVELOPING. A STRONG COLD FRONT IS FORECAST
TO PLOW INTO THE HIGH HEAT AND HUMIDITY ACROSS THE AREA.
THUNDERSTORM DEVELOPMENT WILL OCCUR EITHER LATE IN THE AFTERNOON
TOWARD THE WATERLOO AREA...OR WAIT UNTIL THE EVENING HOURS AND THEN
SPREAD SOUTHEAST. DUE TO THE LARGE AMOUNT OF INSTABILITY AND SOME
AVAILABLE WIND SHEAR...SEVERE STORMS ARE LIKELY.

THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE ALONG AND NORTH
OF INTERSTATE 80...WITH THE POTENTIAL FOR HAIL UP TO THE SIZE OF
GOLFBALLS AND WINDS OVER 70 MPH. SUFFICIENT SHEAR IS PRESENT THAT
SUPERCELLS MAY DEVELOP. IF THIS OCCURS...STRONG TORNADOES
CANNOT BE RULED OUT.

LATE THURSDAY NIGHT INTO FRIDAY...THE SEVERE THREAT WILL BE
REPLACED WITH LOCALLY HEAVY RAINFALL. GENERAL RAINFALL OF ONE HALF
TO ONE INCH IS EXPECTED...WITH LOCALLY HIGHER AMOUNTS UP TO 2 INCHES
POSSIBLE.

ANOTHER STORM SYSTEM IS FORECAST TO AFFECT THE AREA FRIDAY NIGHT
INTO SATURDAY. THIS STORM SYSTEM WILL BRING A GENERAL RAINFALL OF
ONE QUARTER TO ONE HALF INCH. THUNDERSTORMS WILL BE POSSIBLE...
MAINLY SOUTH OF A LINE FROM OTTUMWA IOWA TO PRINCETON ILLINOIS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING.
SPOTTER ACTIVATION IS LIKELY LATE THURSDAY AFTERNOON AND EVENING.