Hail in Illinois, July 11, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
400 PM CDT FRI JUL 11 2003

VORT MAX EVIDENT ON WATER VAPOR IMAGERY EARLIER TODAY NOW MOVING
ACROSS NORTHWEST ILLINOIS. THIS WAVE WAS ROTATING AROUND BACKSIDE OF
NEARLY STACKED LOW OVER NORTHERN LAKE HURON. TSRAS BROKE OUT THIS
MORNING OVER SW WI AND CONTINUE TO PROGRESS SOUTHEAST MAINLY ALONG
AND EAST OF MISSISSIPPI RIVER. STRONGEST STORMS HAVE PRODUCED BRIEF
3/4 INCH HAIL DUE TO RELATIVELY LOW WET BULB ZERO HEIGHTS AROUND 9
KFT ON MORNING SOUNDINGS. THIS ACTIVITY SHOULD DISSIPATE BY EARLY
EVENING AS MID LEVEL SUPPORT SLIDES SOUTHEAST AND WE PASS MAX
HEATING.

TONIGHT THROUGH SATURDAY AFTERNOON...MAIN CHALLENGE IS TEMPERATURES.
MUCH LIKE LAST NIGHT...DIURNAL CLOUDS SHOULD DISSIPATE IN EVENING
WITH ALL AREAS CLEAR BY MIDNIGHT. DEWPOINTS AND UPSTREAM LOWS
SUPPORT ANOTHER COOL AND DRY JULY NIGHT WITH LOWS AGAIN IN UPPER 50S
TO AROUND 60 AND THUS WENT CLOSE TO COOLEST GUIDANCE.
SATURDAY...HIGH CURRENTLY OVER DAKOTAS SLIDES EAST AS LOW OVER GREAT
LAKES PUSHED INTO CANADA. TRIMMED BACK GOING SCATTERED AFTERNOON TO
SLIGHT CHANCE FOR NE HALF...AS AIRMASS PROGGED TO BE MORE STABLE
THAN TODAY WITH MUCH WEAKER WAVE IN NW H5 FLOW AND ALSO LACKING THE
FAVORABLE H25 JET LEVEL WINDS ASSISTING CURRENT CONVECTION. MORE
SUNSHINE THAN ANTICIPATED OVER THE HAS PUSHED TEMPERATURES A BIT
ABOVE WARMEST GUIDANCE HIGHS FOR TODAY...AND THUS WENT CLOSE TO
PERSISTENCE AND SLIGHTLY ABOVE WARMER MAV GUIDANCE FOR SATURDAY.
...SHEETS

SATURDAY NIGHT...
LINGERING SHOWERS WILL DISSIPATE AROUND SUNSET. SURFACE HIGH THEN
BUILDS IN PROVIDING CLEAR SKIES AND LIGHT WINDS. WITH NEARLY IDEAL
RADITIONAL COOLING SETUP...WENT AT OR JUST BELOW LOW END OF GUIDANCE
ON MINS.

SUNDAY AND SUNDAY NIGHT...
SOME MODERATION IN BL TEMPS...BUT LITTLE CHANGE ABOVE...SO TACKED ON
COUPLE 2 DEGS TO MAXES EXPECTED ON SAT. OTHERWISE...LITTLE
WX OF CONSEQUENCE WITH PLENTY OF SUNSHINE AS SURFACE HIGH GRADUALLY
SHIFTS EAST WITH RETURN FLOW SETTING UP LATE.
SOUTH WINDS WILL BRING AN INCREASE IN MOISTURE SUNDAY NIGHT RESULTING
IN WARMER MINS.

MONDAY AND MONDAY NIGHT...
GFS APPEARS TO BE SUFFERING FROM CONVECTIVE FEEDBACK...THUS
DISREGARDED CONVECTIVELY INDUCED VORT MAX AND QPF.
PRESSURE GRADIENT INCREASES WITH SOUTH BREEZES USHERING IN
WARMER AIR AHEAD OF NEXT FRONT DIVING THROUGH THE UPPER MIDWEST AND
PLAINS. PARAMETERS APPEAR IN PLACE FOR MCS DEVELOPMENT
ALONG THE FRONT MONDAY EVENING ACROSS PORTIONS OF MN/SD/NE WITH
FAVORABLE MEAN FLOW AND FORWARD PROPAGATING CORFIDI VECTORS
TO CARRY DEBRIS ACROSS THE NORTH LATE MONDAY NIGHT. THEREFORE
EXPANDED POPS TO INCLUDE AREAS ALONG AND NORTH OF I-80.

EXTENDED (TUE-FRI)...
FRONTAL PASSAGE SLATED TUE WITH MEDIUM RANGE MODELS STILL OFFERING
TIMING DIFFERENCES...THOUGH MINOR ENOUGH TO HAVE LITTLE
IMPACT ON FORECAST. KEPT CHC POPS TUE/TUE EVE BUT BUMPED UP INTO THE
HIGHER END. GFS INDICATING DECENT DIFFLUENCE ALOFT AND LIFT FROM
RIGHT ENTRANCE REGION OF H3 JET. IF LATER RUNS CONTINUE
ADVERTISING THESE DYNAMICS THEN WILL NEED TO CONSIDER RAISING POPS.
CANADIAN HIGH THEN BUILDS IN BEHIND THE FRONT MIDWEEK WITH
MODELS VARYING SOME ON STRENGTH. ECMWF IS ADVERTISING 1030 MB HIGH
UKMET IS A TAD WEAKER THOUGH STILL SHOWING A DECENT HIGH
FOR MID JULY (1024 MB) ENSURING A NICE STRETCH OF WX WED INTO FRI.
DEPENDING UPON THE STRENGTH OF THE HIGH...TEMPS COULD BE
FEW DEGS COOLER THAN GOING FORECAST. THIS WILL NEED TO BE WATCHED.

DVN...
IA...NONE.
IL...NONE.
MO...NONE.

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-121000-

HAZARDOUS WEATHER OUTLOOK...CORRECTED CODING
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
610 AM CDT FRI JUL 11 2003

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

.DAY ONE...TODAY AND TONIGHT...
ISOLATED THUNDERSTORMS MAY BRIEFLY REACH SEVERE LIMITS LATE THIS
AFTERNOON AND EARLY THIS EVENING IN EAST CENTRAL IOWA AND NORTHWEST
ILLINOIS.  THE GREATEST SEVERE WEATHER THREAT WILL BE THREE QUARTER
INCH HAIL AND DAMAGING THUNDERSTORM WINDS.

THE AIR MASS OVER THE MID MISSISSIPPI VALLEY WILL BECOME MODERATELY
UNSTABLE BY THIS AFTERNOON AS TEMPERATURES CLIMB INTO THE LOWER TO
MIDDLE 70S.  A WEAK SURFACE TROUGH...ACCOMPANIED BY AN UPPER LEVEL
DISTURBANCE WILL MOVE SOUTH THROUGH THE REGION...TRIGGERING A FEW
SHOWERS AND THUNDERSTORMS MAINLY DURING THE LATE AFTERNOON AND EARLY
EVENING HOURS.  THE SHOWERS AND THUNDERSTORMS WILL DISSIPATE BY LATE
THIS EVENING WITH THE LOSS OF SURFACE HEATING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY...

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM WILL BE POSSIBLE AGAIN
SATURDAY...MAINLY OVER NORTHWEST ILLINOIS.  THE NEXT CHANCE FOR
THUNDERSTORMS WILL BE TUESDAY...AS A COLD FRONT MOVES THROUGH THE
MID MISSISSIPPI VALLEY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NECESSARY LATE THIS AFTERNOON AND EARLY
THIS EVENING.

&&

MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING URL:
HTTP://WWW.CRH.NOAA.GOV/DVN

DLF

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
101 PM CDT FRI JUL 11 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1255 PM    DUBUQUE                   IA   .25 INCH HAIL
07/11/03   DUBUQUE                        REPORTED BY STORM
                                          SPOTTER.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
345 PM CDT FRI JUL 11 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0344 PM    WARREN                    IL   .25 INCH HAIL
07/11/03   JO DAVIESS                     REPORTED BY STORM
                                          SPOTTER.