Hail in Indiana, June 3, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
650 PM CDT TUE JUN 3 2008

.DISCUSSION...
355 PM CDT

BIG PICTURE IS TRANSITION OF VERY FLAT RIDGE/NEAR ZONAL FLOW EAST
OF THE ROCKIES TO A MEAN TROF OVER THE WEST AND HIGH PLAINS WITH
MULTIPLE DISTURBANCES LIFTING ACROSS THE CENTRAL PLAINS AND THE
UPPER MIDWEST. THIS CHANGE IN LARGE SCALE FLOW ALREADY UNDERWAY
WITH NOSE OF A STRONG JET DIVING TOWARD THE CA-OR BORDER. WITH
PREVAILING SW UPPER FLOW OVER THE REGION TEMPS WILL BE WARM BUT WX
WILL BE UNSETTLED JUST ABOUT EVERY DAY OVER THE NEXT WEEK AS SHORT
WAVES MOVE TO THE UPPER MIDWEST WITH ASSOCIATED SURFACE WAVES
SHIFTING BOUNDARIES BACK AND FORTH ACROSS THE AREA.

IN THE SHORT TERM...SHRA/TSRA HAVE QUICKLY MOVED E OUT OF THE FA
DURING THE EARLY AFTERNOON. SOME CLEARING IN ITS WAKE BUT QUICKLY
FILLING IN WITH BKN CU SOUTH PORTIONS AND LOWER STRATUS/STRATOCU
CEILINGS ACROSS NORTH PORTIONS. SOME DRYING AND COOLING WITH N-NE
SURFACE WINDS BEHIND A SURFACE LOW THAT TRACKS ACROSS NORTHERN IL
MID MORNING AND EARLY AFTERNOON STABILIZING FAR NORTHERN IL
ESPECIALLY WHERE EXTENSIVE CLOUDINESS IS PERSISTING.

UPSTREAM SHORT WAVE MOVING RAPIDLY E ACROSS EASTERN KS AND NEB AT
MID AFTERNOON AND PROGGED TO EASTERN IA AND NE MO BY 00Z WED.
WEAK RADAR ECHOES OCCURRING ACROSS CENTRAL AND NORTHERN MO E INTO
CENTRAL IL. EXPECT MORE VIGOROUS CONVECTION TO DEVELOP LATE
AFTERNOON ACROSS NORTHERN MO WITH PEAK HEATING...LOW LEVEL
MASS AND MOISTURE CONVERGENCE ALONG THE SURFACE FRONT AND
INCREASING UVV AS SHORT WAVE APPROACHES. TSRA THEN EXPECTED TO
MOVE BASICALLY E ALONG THE MAX INSTABILITY AXIS WHERE TEMPS IN MID
AND UPPER 80S AND DEW POINTS IN UPPER 60S AND LOWER 70S. HAVE POPS
RANGING FROM SLIGHT CHC N PART OF FA TO LOW END LIKELY FAR S AS
CHANCE POPS ACROSS WITH ANOTHER BOUNDARY DRAPED ACROSS NORTHERN IL
AND MODERATE INSTABILITY TO ITS S.

AS NEXT SHORT WAVE MOVES OUT OF THE PLAINS LATE TONIGHT AND WED
LOW LEVEL FLOW BACKS AND OVERRUNNING OF SURFACE FRONT INCREASES
ALONG WITH INCREASING UVV IN ADVANCE OF SHORT WAVE. AS UPPER LOW
DEVELOPS OVER THE 4 CORNERS AREA DOWNSTREAM UPPER FLOW BACKS
ALLOWING THE WARM FRONT TO LIFT N OF THE FA FOR THU. MAIN CONVECTIVE
ACTIVITY EXPECTED TO BE N OF THE WI STATE LINE BUT HAVE SLIGHT
CHC TO CHC POPS S IN THE WARM SECTOR WITH UNSTABLE AIRMASS IN PLACE.

AS UPPER LOW OPENS AND LIFTS OUT THU NITE AND FRI A COLD FRONT
TRAILING FROM THE ASSOCIATED SURFACE LOW TRACKING NE INTO ONTARIO
IS FORECAST TO DROP S INTO THE FA...THEN START TO LIFT BACK N SAT
NIGHT AS ANOTHER IMPULSE AND SURFACE WAVE TRACK NE OUT OF THE
PLAINS. WITH WARM MOIST AIRMASS EITHER OVER OR NEARBY TO THE S AND
PERIODIC FRONTAL PASSAGES ASSOCIATED WITH SHORT WAVES TRAVELING NE
ACROSS THE REGION THERE WILL BE A CONTINUED THREAT OF TSRA THRU
EARLY NEXT WEEK.

&&

.AVIATION...

00Z TAFS...MAIN CONCERN THIS PERIOD ARE IFR/LIFR CIGS THRU LATE
WEDNESDAY MORNING. COLD FRONT HAS MOVED SOUTH OF THE TAFS WITH NE
WINDS OFF THE LAKE. THIS HAS ALSO BROUGHT IN CIGS AROUND 500 FEET
AND VISIBILITIES ARE DROPPING UNDER 2SM FROM PWK/UGN NORTH ALONG
THE SHORE. SOUNDINGS SHOW LOW LEVELS CONTINUING TO COOL THROUGH
THE NIGHT WITH NE/ENE FLOW OFF THE LAKE. WHILE RARE FOR EARLY JUNE
CAN/T FIND ANY REASONS WHY LOW CIGS WOULD LIFT/SCATTER OVERNIGHT.
THEREFORE HAVE CONTINUED TREND FROM PREVIOUS FORECAST KEEPING IFR
AND LIFR CIGS IN THRU MID MORNING WEDNESDAY. HAVE ONLY DROPPED
PREVAILING VISIBILITIES TO 2SM BUT SUSPECT SOME AREAS MAY GO LOWER
THAN THIS AND LOCAL FOG PREDICTOR WOULD SUGGEST THAT SOME DENSE
FOG IS ALSO POSSIBLE.

QUESTION THEN BECOMES WHEN DO CIGS LIFT. MODELS DIFFER ON TIMING
AND LOCATION OF WHEN FRONTAL BOUNDARY LIFTS BACK NORTH WEDNESDAY.
HAVE GENERALLY FOLLOWED THE GFS WHICH HAS SFC WINDS BECOMING SSE
BY EARLY/MID AFTERNOON. WITH THIS TIMING IN MIND AND GIVEN THE
STRONG SUN ANGLE IN EARLY MAY HAVE TRENDED TOWARD WHAT MIGHT END
UP BEING AN OPTIMISTIC TREND OF CIGS LIFTING THROUGH MVFR AND
FINALLY SCATTERING OUT BY 20Z. LATER FORECASTS CAN FINE TUNE THE
DETAILS.

SEE LITTLE TO FOCUS ANY CONVECTIVE PRECIP AT THE TERMINALS THRU
THE PERIOD AND HAVE GONE DRY. HOWEVER...COULD BE SOME DRIZZLE OUT
OF THE LOW CIGS TONIGHT AND EARLY WED MORNING. AND SHOWERS ACROSS
EAST CENTRAL IL MAY LIFT NORTHEAST CLOSE TO GYY LATER THIS
EVENING. AS THE WARM FRONT LIFTS BACK NORTH MIDDAY WEDNESDAY...
THERE COULD BE A SHOWER OR TS WITH IT AND AN ISOLATED TS ALSO
POSSIBLE IN THE WARM SECTOR SOUTH OF THE FRONT LATE WEDNESDAY
AFTERNOON. CONFIDENCE ON ANY OF THIS IS LOW ENOUGH TO LEAVE OUT
OF THIS FORECAST. CMS

&&

.MARINE...
248 PM CDT

HIGH PRESSURE OVER SOUTHERN ONTARIO WILL MOVE EAST INTO SOUTHERN
QUEBEC TONIGHT...THEN REMAIN NEARLY STATIONARY THROUGH WEDNESDAY
NIGHT. MEANWHILE...A STATIONARY FRONT EXTENDS EAST FROM A LOW OVER
CENTRAL KANSAS THROUGH CENTRAL ILLINOIS AND INDIANA. THE LOW WILL
TRAVEL EASTWARD ALONG THE FRONT BRINGING A CHANCE OF THUNDERSTORMS
TO SOUTHERN PORTIONS OF THE LAKE TONIGHT. ANOTHER LOW WILL
DEVELOP OVER WESTERN KANSAS BY WEDNESDAY EVENING. THIS LOW WILL
TRACK NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY BY FRIDAY
MORNING...FORCING THE FRONT NORTHWARD AND TURNING WINDS
SOUTHERLY AND INCREASING TO NEAR GALE FORCE LEVELS. A COLD FRONT
ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO SWEEP ACROSS THE LAKE
OVER THE WEEKEND.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM CDT WEDNESDAY FOR LMZ740-LMZ741-
     LMZ742-LMZ743.

&&

HAZARDOUS WEATHER OUTLOOK...CORRECTION NEARSHORE
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT TUE JUN 3 2008

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
042215-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
505 PM CDT TUE JUN 3 2008 /605 PM EDT TUE JUN 3 2008/

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

.DAY ONE...TONIGHT.

WEATHER HAZARDS EXPECTED:

THUNDERSTORMS WITH OCCASIONAL LIGHTNING AND HEAVY DOWNPOURS.

AREAS AFFECTED AND TIMING:

SOUTH OF A ROGERS PARK TO STERLING LINE OVERNIGHT.

DISCUSSION:

AN EARLIER DISTURBANCE HAS MOVED THROUGH THE AREA...CONVERTING
STRONG UNSTABLE SOUTHERLY FLOW INTO A MORE STABLE NORTHEAST FLOW.

A DISTURBANCE WILL BE MOVING EAST INTO THE MID MISSISSIPPI VALLEY
DURING THIS EVENING. THIS COULD INITIATE NEW THUNDERSTORM
DEVELOPMENT ACROSS NORTHERN MISSOURI AND INTO CENTRAL ILLINOIS
DURING OVERNIGHT. THE MOST LIKELY PLACE FOR SEVERE STORMS WOULD
BE SOUTH OF THE OUTLOOK AREA.

PATCHY FOG ALONG THE LAKE MICHIGAN SHORELINE MAY MAKE FOR
HAZARDOUS DRIVING OVERNIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THUNDERSTORMS WILL REMAIN A POSSIBILITY THROUGH LATE FRIDAY WITH
ANOTHER POSSIBLE BOUT WITH SEVERE WEATHER ON FRIDAY AFTERNOON AND
EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ740>745-042215-
WINTHROP HARBOR TO WILMETTE HARBOR-
WILMETTE HARBOR TO NORTHERLY ISLAND-
NORTHERLY ISLAND TO CALUMET HARBOR-CALUMET HARBOR TO GARY-
GARY TO BURNS HARBOR-BURNS HARBOR TO MICHIGAN CITY-
505 PM CDT TUE JUN 3 2008

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

.DAY ONE...TONIGHT.

A SMALL CRAFT ADVISORY IS IN EFFECT UNTIL 100 AM CDT FOR THE
ILLINOIS NEARSHORE WATERS FOR HIGH WINDS AND WAVES.

THERE WILL BY PATCHY FOG OVER THE NEARSHORE WATERS.

THERE IS ALSO A CHANCE OF THUNDERSTORMS ACROSS THE NEARSHORE
WATERS OVERNIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THERE IS A CHANCE FOR THUNDERSTORMS THROUGH FRIDAY NIGHT AND AGAIN
SUNDAY THROUGH MONDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-042215-
LAKE MICHIGAN FROM MICHIGAN CITY IN TO ST. JOSEPH MI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM SEUL CHOIX POINT TO ROCK ISLAND PASSAGE 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN SOUTH OF A LINE FROM SEUL CHOIX POINT TO THE
MACKINAC BRIDGE AND NORTH OF A LINE FROM CHARLEVOIX MI TO SOUTH
FOX ISLAND 5 NM OFFSHORE-
LAKE MICHIGAN FROM CHARLEVOIX TO POINT BETSIE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM POINT BETSIE TO MANISTEE MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI-
LAKE MICHIGAN FROM STURGEON BAY TO TWO RIVERS WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM TOW RIVERS TO SHEBOYGAN WI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM SHEBOYGAN TO PORT WASHINGTON WI 5 NM OFFSHORE
TO MID LAKE-
LAKE MICHIGAN FROM PORT WASHINGTON TO NORTH POINT LIGHT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM NORTH POINT LIGHT TO WIND POINT WI 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WIND POINT WI TO WINTHROP HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM WILMETTE HARBOR IL TO MICHIGAN CITY IN 5 NM
OFFSHORE TO MID LAKE-
LAKE MICHIGAN FROM PENTWATER TO MANISTEE MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM WHITEHALL TO PENTWATER MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM GRAND HAVEN TO WHITEHALL MI 5 NM OFFSHORE TO
MID LAKE-
LAKE MICHIGAN FROM HOLLAND TO GRAND HAVEN MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM SOUTH HAVEN TO HOLLAND MI 5 NM OFFSHORE TO MID
LAKE-
LAKE MICHIGAN FROM ST. JOSEPH TO SOUTH HAVEN MI 5 NM OFFSHORE TO
MID LAKE-
505 PM CDT TUE JUN 3 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE OPEN WATERS
OF LAKE MICHIGAN.

.DAY ONE...TONIGHT.

THERE WILL BE SOME PATCHY FOG ACROSS FAR SOUTHERN LAKE MICHIGAN.

THERE IS A CHANCE OF THUNDERSTORMS ACROSS FAR SOUTHERN LAKE
MICHIGAN OVERNIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THERE IS A CHANCE FOR THUNDERSTORMS ACROSS THE SOUTHERN HALF OF
THE LAKE THROUGH WEDNESDAY. THERE IS A CHANCE FOR THUNDERSTORMS
ACROSS THE ENTIRE LAKE FROM WEDNESDAY EVENING THROUGH FRIDAY
NIGHT...AND AGAIN SUNDAY THROUGH MONDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

RLB