Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 031404
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
904 AM CDT FRI JUL 3 2015

.SHORT TERM...
313 AM CDT

THROUGH SATURDAY...

SATELLITE IMAGERY EARLY THIS MORNING SHOWS A WEAK UPPER LEVEL LOW
OVER THE MID MISSISSIPPI VALLEY PRODUCING EXTENSIVE MID-HIGH LEVEL
CLOUDINESS OVER THE REGION. REGIONAL RADAR MOSAIC DOES SHOW QUITE A
BIT OF RETURNS OVER SE IA/WESTERN ILLINOIS...HOWEVER SURFACE OBS
SUGGEST CLOUD BASES ARE QUITE HIGH AND ONLY SEEN A FEW REPORTS OF
RAIN REACHING THE GROUND. BIG CHANGE TO TODAY`S FORECAST WAS TO BUMP
UP CLOUD COVER CONSIDERABLY INTO EARLY AFTERNOON...WITH GRADUAL
CLEARING LATE IN THE DAY FROM THE NORTH AS THIS SYSTEM SLOWLY PUSHES
SE. ALSO ADDING SOME SLIGHT CHANCE POPS FOR LIGHT SHOWERS/SPRINKLES
TO SOUTHERN CWA. CLOUD COVER SHOULD HELP KEEP TEMPS A BIT COOLER
THAN PREVIOUSLY FORECAST AND HAVE NUDGED HIGHS DOWN A BIT...MAINLY
SOUTHERN HALF OF THE CWA. WINDS OFF THE LAKE SHOULD RESULT IN
ANOTHER DAY IN THE 60S AT THE BEACHES.

HEIGHTS WILL BEGIN TO RISE CONSIDERABLY TONIGHT INTO SATURDAY IN THE
WAKE OF THIS DISTURBANCE WHILE LOW LEVEL FLOW TURNS LIGHT SOUTHERLY
WITH WARM AIR ADVECTION COMMENCING. GRADIENT LOOKS TO BE TOO WEAK TO
PREVENT A LAKE BREEZE FROM FORMING SATURDAY...BUT MAGNITUDE OF LAKE
COOLING SHOULD BE FAR LESS AND WITH AMPLE SUNSHINE TEMPS WILL BE
MUCH WARMER THAN TODAY AND CLOSER TO SEASONAL NORMS.

IZZI

&&

.LONG TERM...
313 AM CDT

SATURDAY NIGHT THROUGH THURSDAY...

SUNDAY LOOKS TO BE QUITE WARM AND GUIDANCE HAS ALL TRENDED WARMER
WITH 925MB TEMPS NOW PROGGED TO BE IN THE 22-24C RANGE SUNDAY
AFTERNOON WHICH WOULD SUPPORT HIGHS IN THE UPPER 80S. ONCE AGAIN
GRADIENT MAY BE TOO WEAK TO TOTALLY SUPPRESS LAKE BREEZE...ESPECIALLY
ALONG ILLINOIS SHORE...BUT LAKE INFLUENCE SHOULD BE MUCH LESS WITH
TEMPS PROBABLY MANAGING TO HIT 80 FOR AT LEAST A TIME ALONG THE
LAKE. STRONGER SOUTHERLY WINDS EXPECTED TO PREVENT LAKE COOLING
MONDAY AHEAD OF THE APPROACHING COLD FRONT. BLENDED MODEL GUIDANCE
HAS HIGHS IN THE MID 80S MONDAY...THOUGH IF CLOUD COVER ISNT TOO
EXTENSIVE WE COULD EASILY BE PUSHING AT LEAST UPPER 80S MONDAY.

COLD FRONT LOOKS TO ARRIVE MONDAY NIGHT/TUESDAY TIME FRAME WITH
ASSOCIATED SHOWER/T-STORM CHANCES ACCOMPANYING THE FRONT. BLENDED
MODEL GUIDANCE WOULD MAINTAIN PERIOD AFTER PERIOD OF POPS TUESDAY
ONWARD...BUT ECMWF AND GFS SUGGEST FRONT CLEARS THE AREA AND SHOULD
ALLOW FOR DRY CONDITIONS TUES NIGHT THROUGH WED EVENING BEFORE FRONT
POTENTIALLY TRIES TO CREEP BACK NORTH AS A WARM FRONT LATER NEXT
WEEK WITH A RETURN OF PRECIP CHANCES.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* WIND SPEEDS OUT OF THE NE/ENE THIS AFTERNOON.

MDB

//DISCUSSION...UPDATED 12Z...

HIGH PRESSURE STRETCHES FROM CENTRAL WISCONSIN EAST TO CENTRAL
MICHIGAN THIS MORNING AND WILL GRADUALLY SLIDE SOUTH THROUGH THE
TAF PERIOD. LIGHT WINDS WILL BE IN PLACE OUT OF THE NORTHEAST
THROUGH MIDDAY. WINDS WILL LIKELY PICK-UP SLIGHTLY WITH A LAKE
BREEZE THIS AFTERNOON...HOWEVER MODELS CONTINUE TO KEEP WINDS
SPEEDS BELOW 10 KT BEHIND THE BOUNDARY. EXPECT VFR CONDITIONS
THROUGH THE FORECAST PERIOD.

BMD

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* MEDIUM-HIGH IN WINDS STAYING AT OR BELOW 10 KT.
* HIGH IN REMAINING FORECAST ELEMENTS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...

SATURDAY NIGHT...DRY. VFR. S WINDS.
SUNDAY...DRY. VFR. S WINDS. LAKE BREEZE PSBL.
MONDAY...TSRA LIKELY LATE. SW WINDS.
TUESDAY...CHC TSRA. NW WINDS BECOMING NE.
WEDNESDAY...DRY. VFR. E WINDS.
THURSDAY...CHC TSRA. NW WINDS.

BMD

&&

.MARINE...
240 AM CDT

A RIDGE STRETCHES FROM WISCONSIN ACROSS SOUTHERN LAKE MICHIGAN
INTO MICHIGAN THIS MORNING RESULTING IN LIGHT AND VARIABLE WINDS
ACROSS THE SOUTH HALF OF THE LAKE...AND SOUTHWEST WINDS ACROSS THE
NORTH. THE NORTHERN HALF OF THE LAKE WILL SEE WINDS INCREASING
INTO THE 15 TO 25 KT RANGE THIS AFTERNOON AND EVENING AHEAD OF AN
APPROACHING FRONT. MEANWHILE...THE SOUTH HALF WILL CONTINUE TO
SEE LIGHT WINDS WITH LAKE BREEZES RESULTING IN ONSHORE FLOW THIS
AFTERNOON. THE FRONT WILL BEGIN TO SAG ACROSS THE NORTH HALF OF
LAKE MICHIGAN LATE TONIGHT...DROPPING TO AROUND MIDLAKE
SATURDAY...THEN LIFTING NORTH AGAIN. SOUTH WINDS FRESHEN UP ACROSS
THE LAKE AGAIN SUNDAY NIGHT INTO MONDAY AHEAD OF A STRONGER COLD
FRONT PROGGED TO SWEEP ACROSS THE LAKE MONDAY NIGHT.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

$$

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