Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 301911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
211 PM CDT TUE JUN 30 2015

.SHORT TERM...
210 PM CDT

THROUGH WEDNESDAY...

DECIDED TO REDUCE THE PRECIPITATION OUTLOOK SIGNIFICANTLY FOR THIS
AFTERNOON. THE MAIN UPPER LEVEL WAVE IS WELL TO OUR EAST OVER
EASTERN MI AND OHIO AND THICK CLOUD COVER IS NORTH OF I-80.  WAS
ORIGINALLY THINKING A FEW SHOWERS WOULD DEVELOP ALONG THE LAKE
BREEZE...BUT THE CLOUD COVER WILL LIKELY LIMIT ANY VERTICAL GROWTH
ESPECIALLY SINCE MOST PLACES HAVE NOT WARMED AS QUICKLY AS
ORIGINALLY THOUGHT.  KEPT A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN FORD...IROQUOIS...AND BENTON COUNTIES THIS AFTERNOON
ALTHOUGH WITHOUT ANY CLEAR FORCING...HAVE LOW CONFIDENCE IN ANY
SHOWERS OR STORMS FORMING.  THE LATEST RAP ANALYSIS DOES FEATURE
AROUND 1500 J/KG OF CAPE SOUTH OF I-80 SO IF ANY FORCING DOES
DEVELOP...STORMS ARE POSSIBLE.

EXPECTING DRY CONDITIONS THROUGH WEDNESDAY AS THE NEXT CONVECTIVE
SYSTEM WILL PASS TO OUR SOUTH OVER CENTRAL ILLINOIS.  TO PLAY IT
SAFE...PUT A SLIGHT CHANCE OF STORMS SOUTH OF A PONTIAC IL TO FOWLER
INDIANA LINE LATE WEDNESDAY AFTERNOON...BUT HAVE MEDIUM-LOW
CONFIDENCE IN STORMS GETTING THAT FAR NORTH TOMORROW.

DID NOT MAKE ANY MAJOR CHANGES TO TEMPS FOR TONIGHT AND TOMORROW.
WITH INCREASING CLOUD COVER OVERNIGHT AND DEWPOINTS IN THE MID 50S
TO LOW 60S...LOW TEMPS WILL GET INTO THE MID TO UPPER 50S. FLOW WILL
BE OFF OF THE LAKE TOMORROW RESULTING IN UNSEASONABLY COOL TEMPS
WITH HIGHS IN THE 70S. LOCATIONS ALONG THE LAKE WILL LIKELY STAY IN
THE LOW TO MID 60S.

JEE

&&

.LONG TERM...
325 AM CDT

WEDNESDAY NIGHT THROUGH MONDAY...

EXTENDED PERIOD OF DRY AND SEASONABLY COOL WEATHER EXPECTED TO
CONTINUE INTO THE WEEKEND AS UPPER TROUGH SLOWLY DEAMPLIFIES BUT
WEAK CANADIAN HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. WINDS
OFF THE LAKE WILL KEEP IT CONSISTENTLY COOLER BY THE LAKE WITH HIGHS
GENERALLY IN THE 70S INLAND AND 60S RIGHT ALONG THE LAKE. MODERATING
TREND IN TEMPS EXPECTED HEADING INTO THE WEEKEND AS DEVELOPING LOW
PRESSURE OVER THE PLAINS FLIPS WINDS TO SOUTHERLY DIRECTION AND
BRINGS A RETURN TO MORE SEASONABLE TEMPERATURES OVER THE WEEKEND
ALONG WITH A THREAT OF SOME SHOWERS AND THUNDERSTORMS BY SUNDAY
NIGHT INTO MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 19Z...

* MVFR CEILINGS POSSIBLE THIS AFTERNOON.

* SMALL CHANCE FOR LIGHT SHOWERS THIS AFTERNOON.

* LAKE BREEZE DEVELOPMENT THIS AFTERNOON.

* LOW MVFR CEILINGS OVERNIGHT.

MM

//DISCUSSION...UPDATED 19Z...

VISIBLE SATELLITE IMAGERY INDICATES A BROKEN TO OVERCAST STRATUS
DECK APPROACHING FROM THE NORTHWEST BEHIND A PASSING COLD FRONT.
THE REDUCED SUNSHINE DUE TO THESE CLOUDS WILL LOWER THE THREAT OF
SHOWERS DEVELOPING TO ONLY 30 PERCENT...PRECLUDING MENTION IN THE
TAFS. THIS WILL ALSO ACT TO WEAKEN AND DELAY THE LAKE BREEZE
DEVELOPMENT. START TIME OF LAKE BREEZE HAS BEEN ADJUSTED PER
LATEST RADAR TRENDS. REMNANT LOW LEVEL MOISTURE WILL KEEP 1500
FOOT CEILINGS LIKELY LATE TONIGHT. ONCE THE SURFACE HIGH GETS
CLOSER WEDNESDAY MORNING...CLOUD COVER WILL SCATTER OUT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 19Z...

* MEDIUM IN CIGS REMAINING ABOVE MVFR THIS AFTERNOON.

* MEDIUM HIGH THAT SHOWERS WILL NOT DEVELOP.

* MEDIUM IN LAKE BREEZE DEVELOPMENT AND TIMING.

* MEDIUM IN LOW MVFR CIGS OVERNIGHT.

MM

//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...

WEDNESDAY NIGHT THROUGH SUNDAY...PRIMARILY DRY AND VFR. NE/E WINDS.
MONDAY...CHC TSRA. SW WINDS.

BMD

&&

.MARINE...
259 AM CDT

A WEAK TROUGH WILL PUSH ACROSS LAKE MICHIGAN TODAY WITH NORTHWEST
TO NORTH WINDS OVERSPREADING THE LAKE THROUGH THE DAY. WINDS
FRESHEN UP TO 15 TO 20 KT ACROSS THE LAKE THIS AFTERNOON AND
EVENING AS THE LOW DEEPENS OVER THE EASTERN LAKES REGION AND HIGH
PRESSURE BUILDS SOUTH FROM MANITOBA. MODEST NORTH TO NORTHEAST
WINDS WILL REMAIN IN PLACE THROUGH WEDNESDAY NIGHT...THEN WILL
BEGIN TO DIMINISH FROM THE NORTH. A GRADIENT WILL HOLD ON ACROSS
THE FAR SOUTH END OF LAKE MICHIGAN THURSDAY AS LOW PRESSURE MOVES
ACROSS THE MID MISSISSIPPI VALLEY...BUT EXPECT WINDS TO DIMINISH
ACROSS THE SOUTH END BY THURSDAY NIGHT AS THE RIDGE CONTINUES TO
BUILD SOUTH.

BMD

&&

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

$$

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