Damaging Wind in Illinois, June 12, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
320 AM CDT TUE JUN 12 2001

MULTIPLE THUNDERSTORM CLUSTERS CONTINUE FROM NORTHERN IOWA INTO
SOUTHERN WISCONSIN AND NORTHERN PORTIONS OF ILLINOIS AND INDIANA AT
08Z. PROFILER NETWORK INDICATES 40 KNOT 850MB JET FEEDING INTO THESE
COMPLEXES...WITH 850-300 MB THICKNESS AND CORFIDI PROPAGATION
VECTORS SUGGESTING SLOW EASTWARD MOVEMENT OF CELLS OVER NORTHEAST
IA/SOUTHWEST WISCONSIN TO CONTINUE...WHILE ACTIVITY FARTHER EAST IN
INDIANA SINKS SOUTHWARD. ETA FORECAST SHOWS JET WEAKENING AND
BECOMING MORE WESTERLY BY 12Z OVER IA/IL...REFOCUSING BETTER INFLOW
BACK ACROSS THE PLAINS INTO NEBRASKA. ACTIVITY IS NOW ELEVATED NORTH
OF OUTFLOW FROM SEVERE CONVECTION EARLIER...WITH PRIMARY THREAT NOW
TURNING TO HEAVY RAIN...ESPECIALLY NORTH CENTRAL IL COUNTIES NEAR
WISCONSIN BORDER NEXT COUPLE OF HOURS. FLASH FLOOD GUIDANCE FOR
THESE COUNTIES AROUND 2.5 INCHES...AND THIS AREA MISSED MOST OF THE
RAIN FROM EARLIER IN THE NIGHT. MOST INTENSE CONVECTION PASSING JUST
NORTH OF THE BORDER SO NO BIG PROBLEMS ANTICIPATED FOR NOW ALTHOUGH
WILL CONTINUE TO MONITOR RADAR TRENDS.

WILL HAVE TO KEEP MORNING MENTION OF SHOWERS/STORMS MAINLY NORTHERN
AREAS FOR ONGOING PRECIP. FORECAST THEN TURNS MORE THAN A BIT
MESSY...WITH DEBRIS CLOUDINESS AND VERY COMPLICATED SURFACE PRESSURE
PATTERN OVER THE FORECAST AREA TODAY. MORNING CLOUD COVER MAY KEEP
TEMPS A BIT LOWER TODAY...ALTHOUGH PROBABLY WILL SEE A GOOD AMOUNT
OF SUN BY AFTERNOON. NEXT QUESTION IS CONVECTIVE REDEVELOPMENT LATER
THIS AFTERNOON AND EVENING WITH OUTFLOW BOUNDARY/WARMFRONT STRETCHED
ACROSS NORTHERN ILLINOIS POTENTIALLY PROVIDING ENOUGH LOW LEVEL
CONVERGENCE TO INITIATE CONVECTION IN WARM...MOIST AND UNSTABLE
ATMOSPHERE. ETA AGAIN PROBABLY OVERDOING SURFACE DEWPOINTS...WITH
FORECAST SOUNDINGS SHOWING 3000-5000 J/KG LATER TODAY...BUT COULD BE
SOME STRONG STORMS PER SPC DAY 1 OUTLOOK.

OUTFLOW BOUNDARY/WARMFRONT SHOULD LIFT NORTH INTO MINNESOTA AND
WISCONSIN LATER TONIGHT...WITH HEIGHTS RISING OVER IL AND IND AS
UPPER RIDGE BUILDS AHEAD OF PACIFIC NORTHWEST UPPER LOW. THIS SHOULD
KEEP PRECIP THREAT LOW UNTIL UPPER LOW AND SURFACE COLD FRONT
APPROACH ON THURSDAY. WEDNESDAY SHOULD BE ANOTHER HOT ONE...WITH 850
MB TEMPS AROUND +21 C SUGGESTING TEMPS IN LOWER 90S ACROSS MUCH OF
FORECAST AREA. COOLER BEHIND FRONT BY WEEKEND.

.CHI...NONE./

RATZER

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE CHICAGO IL
136 AM CDT TUE JUN 12 2001

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

1200 AM    NAPERVILLE MILL AND FERRY IL   60 MPH TSTM GUST
06/12/01   DUPAGE                         REPORTED BY EMERGENCY
                                          MANAGEMENT.

1230 AM    HIGHLAND PARK             IL   WIND DAMAGE
06/12/01   LAKE                           TREES AND POWER LINES
                                          DOWN. REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

1235 AM    WHEATON                   IL   WIND DAMAGE
06/12/01   DUPAGE                         POWER LINE DOWN.
                                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

1240 AM    CHICAGO                   IL   WIND DAMAGE
06/12/01   COOK                           TREE/POWER LINE/LIGHT
                                          POLES DOWN. REPORTED BY
                                          EMERGENCY MANAGEMENT.

1255 AM    CHESTERTON                IN   WIND DAMAGE
06/12/01   PORTER                         TREES AND POWER LINES
                                          DOWN. REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

0100 AM    OAK LAWN                  IL   WIND DAMAGE
06/12/01   COOK                           POWER LINES DOWN.
                                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

0102 AM    THROUGHOUT COUNTY         IN   WIND DAMAGE
06/12/01   PORTER                         POWER LINES/TREES DOWN.
                                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

...CORRECTED HIGHLAND TO HIGHLAND PARK IN SECOND REPORT...

ILZ003>006-008-010>014-019>023-032>033-039-INZ001>002-010>011-019-
131100-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
1200 PM CDT/EST TUE JUN 12 2001

FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT ACROSS NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST
INDIANA. THE SLIGHT RISK AREA IS NORTH OF LINE FROM LAFAYETTE
INDIANA TO BLOOMINGTON ILLINOIS.

A WARM FRONT LIES ACROSS CENTRAL ILLINOIS LATE THIS MORNING. VERY
WARM AND MOIST AIR LIES SOUTH OF THIS FRONT WITH TEMPERATURES
CLIMBING INTO THE 80S AND DEWPOINTS IN THE LOWER 70S. NORTH OF THIS
FRONT...CLOUDY SKIES AND COOL TEMPERATURES PERSIST. SKIES ARE
EXPECTED TO BECOME PARTLY SUNNY THIS AFTERNOON ACROSS THE REGION AS
TEMPERATURES WARM INTO THE 80S. AS THIS WARM FRONT BEGINS TO MOVE
NORTH ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA THIS
AFTERNOON...THUNDERSTORMS ARE POSSIBLE.

DUE TO THE AMOUNT OF INSTABILITY EXPECTED TODAY...SOME OF THE STORMS
THAT DEVELOP COULD POTENTIALLY BECOME SEVERE...CAPABLE OF PRODUCING
DAMAGING WINDS AND LARGE HAIL. THE FRONT SHOULD LIFT NORTH OF THE
AREA TONIGHT...ENDING THE THREAT OF STORMS.

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON AND THIS
EVENING.

BE ALERT FOR THE POSSIBILITY OF THREATENING WEATHER LATER
TODAY. STAYED TUNED TO NOAA WEATHER RADIO AND MEDIA OUTLETS FOR THE
LATEST INFORMATION AND STATEMENTS FROM THE NATIONAL WEATHER SERVICE.

CMS