Hail in Indiana, June 26, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
110 PM CDT MON JUN 26 2006

.DISCUSSION...

WILL NOT MAKE BIG CHANGES IN THE ONGOING FORECAST. THE 500 MB TROUGH
WILL BE OVER NORTHERN ILLINOIS AND NORTHWEST INDIANA THROUGH
WEDNESDAY. THERE WILL BE A CHANCE OF THUNDERSTORMS EACH DAY. THE
TEMPERATURE AT 500 MB -16 DEGREE C OVER MINNESOTA AT 00 UTC. LIGHT
NORTHWEST WIND UP TO AROUND 600 MB ON THE WINCHESTER PROFILER AND
A SOUTHEAST WIND ON THE ACARS SOUNDING FROM ORD AT 0830 UTC. THIS
SHOWS THE UPPER AIR TROUGH AXIS OVER WESTERN ILLINOIS AND A SURFACE
TROUGH OVER EASTERN ILLINOIS. THE SURFACE TROUGH AXIS IS FORECAST TO
DRIFT SOUTH OF NORTHWEST INDIANA AND NORTHEAST ILLINOIS THIS
AFTERNOON. MOST OF THE THUNDERSTORMS WILL BE FURTHER SOUTH THAN THIS
MORNING. THE THUNDERSTORMS WILL OCCUR WHEN INDIVIDUAL SMALL TROUGHS
ROTATE THROUGH. USING THE OMEGA FIELD AT 700 MB NEGATIVE OMEGA IS
FORECAST BETWEEN 18 UTC AND 00 UTC TODAY 06 TO 12 UTC TUESDAY
MORNING.

&&

.AVIATION...

18 Z TAFS...MAIN FORECAST ISSUE FOR THIS SET OF TAFS IS THE CHANCE
OF PRECIPITATION THROUGH THE PERIOD.  INITIAL CONVECTION OCCURRING
IN NORTHERN ILLINOIS ALONG SOME SORT OF OLD BOUNDARY HAS ONLY A VERY
ISOLATED THREAT FOR THUNDER...SO FOR THE INITIAL STAGES KEPT THUNDER
OUT OF THE FORECAST FOR THE TAF SITES.  THE NEXT AXIS OF INSTABILITY
HAS ALREADY INITIATED JUST WEST OF THE ILLINOIS/INDIANA STATE LINE
ALONG AND EAST OF THE SURFACE TROF AXIS.  THIS POCKET OF INSTABILITY
WILL PROPAGATE NORTHWARD INTO NORTHEASTERN ILLINOIS/NORTHWESTERN
INDIANA THROUGH THE LATE AFTERNOON AND EARLY EVENING AND WILL
INCREASE THE THREAT FOR THUNDERSTORMS ACROSS THE REGION.  A LULL IN
SHRA AND TSRA IS EXPECTED FROM ABOUT 00 UTC THROUGH 06 UTC AS A
SMALL AREA OF SUBSIDENCE SETTLES IN BEHIND THESE STORMS...BUT THEN
EXPECTING ANOTHER ROUND OF PRECIP OVERNIGHT AND INTO THE EARLY
MORNING AS THE VERTICAL VELOCITIES PICK UP AGAIN.

ANOTHER ISSUE OF CONCERN IS THE CHANCES FOR FOG OVERNIGHT.  LATEST
FOGGY INDEX INDICATES TURBULANT EDDIES AND FAVORS STRATUS OVER
FOG...BUT WITH 1+ OF RAINFALL ACROSS MOST OF THE REGION
YESTERDAY...THE TOPSOIL SHOULD BE RATHER MOIST.  WITH WINDS BECOMING
LIGHT AND VARIABLE OVERNIGHT...THERE COULD BE SOME RADIATIONAL FOG
THAT DEVELOPS...BUT THIS MAY BE HINDERED DUE TO A MID-LEVEL DECK OF
CLOUDS THAT WILL LIMIT HOW STRONG THE INVERSION GETS.  THE NEXT
SHIFT SHOULD BE ABLE TO GET A FIRMER GRASP ON WHAT WILL WIN OUT
OVERNIGHT.

IFR CONDITIONS WILL BE THE NORM THROUGHOUT THE TAF PERIOD...BUT SOME
BRIEF MVFR CONDITIONS ARE POSSIBLE NEAR THUNDERSTORMS AS CLOUD BASES
WILL LOWER TO AROUND 2KFT AT TIMES AS WELL WITH THE POSSIBILITY OF
FOG OVERNIGHT.

HALBACH

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
.IL...NONE.
.IN...NONE.
.LM...SMALL CRAFT ADVISORY.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
700 AM CDT MON JUN 26 2006

ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011-
019-270930-
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
430 AM CDT MON JUN 26 2006

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL
AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE... TODAY AND TONIGHT

.THERE WILL BE A CHANCE OF THUNDERSTORMS FOR ALL OF NORTH CENTRAL
AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA TODAY AND TONIGHT.

A SLIGHT RISK OF SEVERE THUNDERSTORMS WILL BE OVER SOUTHERN FORD
COUNTY AND SOUTHERN IROQUOIS COUNTY IN ILLINOIS AND SOUTHERN BENTON
COUNTY INDIANA. THE MAIN THREAT WILL BE DAMAGING WIND AND LARGE
HAIL.

ANOTHER THREAT FOR THE ENTIRE REGION WILL BE BRIEF PERIOD OF HEAVY
RAIN IN THE THUNDERSTORMS. THE RAINFALL MAY PRODUCE LOCAL FLOODING
IN LOW LYING AREAS AND AREAS OF POOR DRAINAGE. THERE MAY BE PONDING
OF WATER ON ROADS AND STREETS.

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

THERE WILL BE A CHANCE OF THUNDERSTORMS TUESDAY THROUGH WEDNESDAY
NIGHT. A SLIGHT RISK OF SEVERE THUNDERSTORMS IS POSTED FOR WEDNESDAY
TROUGH WEDNESDAY NIGHT. THE RISK IS FOR SOUTHEASTERN FORD COUNTY...
SOUTHERN IROQUOIS IN ILLINOIS AND BENTON COUNTY IN INDIANA.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED FOR THE SOUTHERN COUNTIES THIS AFTERNOON.
REPORT FLOODING...HIGH WATER ON ROADS AND FLOOD DAMAGE.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE)

LMZ740>745-766-270930-
WINTHROP HARBOR IL TO MICHIGAN CITY IN-
LAKE MICHIGAN-
700 AM CDT MON JUN 26 2006

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS
AND INDIANA WATERS OF LAKE MICHIGAN.

.DAY ONE... TODAY AND TONIGHT

A SMALL CRAFT ADVISORY FOR WAVES UP TO 7 FEET IS IN EFFECT FROM
NORTHERLY ISLAND TO MICHIGAN CITY INDIANA UNTIL 10PM CDT THIS
EVENING. THERE IS ALSO A CHANCE OF THUNDERSTORMS TODAY AND
TONIGHT.

.DAYS TWO THROUGH SEVEN... TUESDAY THROUGH SUNDAY

THERE WILL BE A CHANCE OF THUNDERSTORMS TUESDAY THROUGH WEDNESDAY
NIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE
NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE)