Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 021733
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1233 PM CDT THU JUL 2 2015

.UPDATE...
839 AM CDT

QUICK UPDATE TO INCREASE SKY COVER OVER NORTHEAST ILLINOIS.
WEBCAMS AND AMDAR SOUNDINGS CONFIRM THE CLOUD DECK IS NOT SUPER
THICK. CLOUDS WILL CONTINUE TO THIN AFTER SOME INITIAL
OVERTURNING. NO PRECIPITATION IS EXPECTED WITH THIS LOWER CLOUD
DECK.

KMD

&&

.SHORT TERM...
248 AM CDT

THROUGH FRIDAY...

ABOUT THE ONLY THINGS TO TALK ABOUT IN THE SHORT TERM ARE COOLER
TEMPS NEAR THE LAKE AND POTENTIAL FOR CANADIAN WILDFIRE SMOKE TO
FILTER SUNSHINE AND PERHAPS KEEP TEMPS A HAIR COOLER. OTHERWISE LOOK
FOR QUIET AND SEASONABLY COOL MID SUMMER WEATHER TODAY AND INTO
TOMORROW AS WELL. NOAA SATELLITE DATA SUGGESTS FAIRLY HEAVY SMOKE
PLUME ALOFT OVER THE REGION AND WITH UPPER LEVEL WINDS LIKELY TO
CONTINUE TO ADVECT SMOKE INTO THE AREA SUSPECT SUNSHINE WILL BE
FILTERED BY SMOKE TO AT LEAST SOME EXTENT THE NEXT COUPLE DAYS...SO
PLAN TO HANDLE THE PARTIALLY OBSCURED SUNSHINE WITH HAZE MENTION IN
THE GRIDS/TEXT PRODUCTS.

IZZI

&&

.LONG TERM...
248 AM CDT

FRIDAY NIGHT THROUGH WEDNESDAY...

TEMPS WILL REBOUND TO NEAR SEASONAL NORMS FOR THE WEEKEND WITH
AFTERNOON LAKE BREEZES HAVING FAR LESS INFLUENCE BOTH SPATIALLY AND
IN MAGNITUDE ON TEMPS. FORECAST SOUNDINGS SUGGEST SKIES WILL BE
FAIRLY CLEAR...THOUGH AGAIN IT IS POSSIBLE THAT SMOKE COULD OBSCURE
SUN SOME...BUT WITH UPPER LEVEL WINDS BACKING MORE WESTERLY SUSPECT
SMOKE WILL BECOME LESS OF A FACTOR. MEDIUM RANGE MODELS CONTINUE TO
SLOW THE ARRIVAL OF NEXT COLD FRONT WITH MONDAY NIGHT NOW MORE
FAVORED...THOUGH SOME OF THE SLOWER GUIDANCE LIKE THE ECMWF WOULD
EVEN SUGGEST MORE OF A TUESDAY EVENT WITH REGION SQUEAKING OUT
ANOTHER DRY/WARM DAY ON MONDAY.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHEAST WINDS AT 12KT.

* SLIGHT CHANCE FOR MVFR BR LATE TONIGHT.

MM

//DISCUSSION...UPDATED 18Z...

HIGH PRESSURE ENCOMPASSING THE GREAT LAKES REGION WILL KEEP QUIET
WEATHER IN PLACE ACROSS THE TERMINALS. IR SATELLITE IMAGERY
INDICATES SOME HIGH CLOUDS STREAMING INTO THE REGION FROM
CONVECTION ONGOING IN THE MID MISSISSIPPI VALLEY. THESE HIGHER
CLOUDS SHOULD THICKEN TO A BKN DECK OVER 10KFT LATE TONIGHT.
WITH HIGH PRESSURE OVERHEAD...FORECAST SOUNDINGS SHOW A
MODERATELY STRONG INVERSION FROM 06-12Z TONIGHT WHICH WOULD
LEAD TO SOME PATCHY FOG ACROSS THE TERMINALS. EXPECTED CLOUD
COVER TONIGHT SHOULD MITIGATE THE INVERSION STRENGTH. ALSO SURFACE
MOISTURE CONTENT IS LOWER THAN THE PAST TWO NIGHTS...SO WILL NOT
INCLUDE BR IN THE TAFS AT THIS POINT.

MM

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM-HIGH CONFIDENCE IN NO FOG LATE TONIGHT.

* HIGH CONFIDENCE ALL WEATHER ELEMENTS.

MM

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

FRIDAY NIGHT...DRY. VFR. LGT VRB WINDS.
SATURDAY...DRY. VFR. SW WINDS TURNING E.
SUNDAY...DRY. VFR. SE WINDS.
MONDAY...CHC TSRA. SW WINDS.
TUESDAY...CHC TSRA. NW WINDS TURNING NE.
WEDNESDAY...DRY. VFR. NE WINDS.

BMD

&&

.MARINE...
321 AM CDT

A RIDGE OF HIGH PRESSURE STRETCHES ACROSS THE NORTHERN HALF OF
LAKE MICHIGAN THIS MORNING WITH A MODEST GRADIENT IN PLACE
ACROSS THE SOUTH HALF RESULTING IN 15 TO 20 KT WINDS. THESE WINDS
WILL CONTINUE TODAY THEN SHOULD BEGIN TO DIMINISH TONIGHT AS THE
RIDGE AXIS SLIDES SOUTH DOWN THE LAKE. SOUTHWEST WINDS WILL
FRESHEN UP ACROSS THE NORTHERN HALF ON FRIDAY AHEAD OF A COLD
FRONT THAT WILL STALL OUT OVER THE FAR NORTH LAKE FRIDAY NIGHT.
THE FRONT LIFTS BACK NORTH THROUGH THE DAY SATURDAY. A STRONGER
COLD FRONT IS EXPECTED LATE MONDAY INTO EARLY TUESDAY.

BMD

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM FRIDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM FRIDAY.

LM...NONE.
&&

$$

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