Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 012158
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
458 PM CDT MON JUN 1 2015

.SHORT TERM...
259 PM CDT

THROUGH TUESDAY...

EXPANSIVE HIGH PRESSURE OVER THE NORTHERN GREAT LAKES WILL SETTLE
SOUTHWARD...EVENTUALLY BRINGING CLEAR SKIES EVEN TO AREAS SOUTH OF
I-80 WHERE PESKY STRATUS HAS HUNG ON TODAY. LIGHT TO CALM WINDS
AND CLEAR SKIES OVERNIGHT WILL YIELD LOWS BY EARLY TUESDAY
PRIMARILY IN THE 40S...BUT EXPECTING SOME RARE JUNE UPPER 30S IN
FAR NORTHEAST IL. ALSO IT STILL APPEARS ROCKFORD COULD COME CLOSE
TO ITS RECORD LOW OF 41 FOR JUNE 2ND. HAVE SOME CONCERN THAT THERE
COULD BE PATCHY FOG DEVELOPMENT IN SOUTHEAST PORTIONS OF CWA STILL
HOLDING ONTO CLOUD COVER AS OF MID AFTERNOON. DEWPOINTS REMAIN IN
THE 50S IN THESE AREAS THAT ALSO OBSERVED THE MOST SIGNIFICANT
RAIN AMOUNTS OVER THE WEEKEND. NONE OF THE MOS AND HI-RES GUIDANCE
IS HITTING FOG HARD...BUT WILL PASS ON CONCERNS TO EVENING SHIFT
TO MONITOR.

OTHER THAN MAYBE A FEW PUFFY FAIR WEATHER CU AT TOP OF MIXED LAYER
NEARING 850 MB ON TUESDAY...EXPECTING SUNNY SKIES. POSITION OF
SURFACE HIGH OVER CENTRAL GREAT LAKES WITH RIDGING BACK ACROSS
LAKE MICHIGAN WILL RESULT IN SYNOPTIC EAST-NORTHEAST TO EAST-
SOUTHEAST FLOW...AND SLIGHTLY ENHANCED LAKE BREEZE PUSH EASILY
ABLE TO SPREAD INLAND DURING THE AFTERNOON. CLIMO OF PROGGED
850/925 MB TEMPS SUPPORTS LOWER-MID 70S INLAND...SO A NICE
RECOVERY FROM TODAY. ALSO AIDING IN WARMING COULD BE SOME MIXING
OUT OF DEWPOINTS DURING THE AFTERNOON. UNFORTUNATELY THE LAKESHORE
AREAS WILL AGAIN BE KEPT COOLER BY ONSHORE FLOW...GENERALLY IN THE
UPPER 50S TO LOWER/PERHAPS MID 60S.

RC

&&

.LONG TERM...
317 PM CDT

TUESDAY NIGHT THROUGH MONDAY...

WHILE A SURFACE RIDGE WILL BE SLOW TO DEPART THE AREA DURING
MIDWEEK...ITS WEAKENING ALONG WITH VEERING FLOW ALOFT WILL ALLOW FOR
GRADUAL MODERATION IN TEMPERATURES. READINGS AT NORMAL ARE EXPECTED
BY WEDNESDAY. THE WEAKENING UPPER LOW ACROSS THE TENNESSEE VALLEY /
SOUTHEAST U.S. DURING WEDNESDAY INTO THURSDAY WILL LIMIT ANY
APPRECIABLE RETURN FLOW INTO THE AREA. LOW PRESSURE ACROSS THE
CENTRAL PLAINS IS FORECAST BY MOST GUIDANCE TO WEAKEN AS IT MOVES
EASTWARD...THOUGH THE 12Z GEM DOES ACTUALLY STRENGTHEN THIS BUT IS
AN OUTLYING SOLUTION. LIFT AND MOISTURE ARE LIMITED ON THURSDAY AHEAD
OF THIS FEATURE...WITH SLIGHTLY GREATER MOISTURE CONVERGENCE AND
SUPPORT FOR SHOWERS AND THUNDERSTORMS THURSDAY NIGHT.

A COLD FRONT IS FORECAST TO DEVELOP AHEAD OF AN IMPINGING HIGH FROM
THE NORTH ON FRIDAY AND DROP SOUTH THROUGH THE AREA. CONFIDENCE IS
LOW ON THE PRECISE TIMING OF THIS AND LIKEWISE IS LOW ON
TEMPERATURES INTO THIS WEEKEND. THE MAGNITUDE OF THE COOL AIR IS
CERTAINLY NOT TO WHAT WE JUST EXPERIENCED...THOUGH LAKESIDE AREAS
COULD BE ONLY AROUND 60 FOR HIGHS BY FRIDAY AFTERNOON AND AGAIN ON
SATURDAY. WHILE THERE IS A LOT OF SPREAD IN SOLUTIONS...THERE IS
CONSENSUS ON RETURN FLOW BY LATE IN THE WEEKEND WHICH COULD
PROVIDE FOR BETTER CHANCES FOR THUNDERSTORMS AT THE START OF NEXT
WEEK.

MTF

&&

.CLIMATE...

ROCKFORD IS PRESENTLY FORECAST TO BE CLOSE TO A RECORD LOW
TUESDAY MORNING JUNE 2ND. THE RECORD LOW IS 41 SET IN 2003.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* NORTHEAST WINDS NEAR 12KT THROUGH EARLY EVENING.

MM/RATZER

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

VISIBLE SATELLITE TRENDS INDICATE A QUICKLY DETERIORATING MVFR
CLOUD MASS NEAR LAKE MICHIGAN. NEAR OR IMMEDIATELY AFTER TAF
ISSUANCE TIME...THESE CEILINGS ARE EXPECTED TO SCATTER OUT. OVERALL
DRY AIR MASS WILL ALLOW SKIES TO CLEAR OUT COMPLETELY THIS
AFTERNOON THROUGH THE OVERNIGHT.

HIGH PRESSURE TO THE NORTHEAST WILL KEEP WINDS EASTERLY THROUGH
TOMORROW. FEW TO SCATTERED CLOUDS ARE EXPECTED IN THE
AFTERNOON...AND WINDS ALOFT APPEAR TO BE VERY WEAK WHICH PRECLUDES
MENTION OF ANY GUSTS.

MM

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH CONFIDENCE IN WIND SPEEDS UNDER 15 KT THROUGH THIS
  EVENING.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

MM/RATZER

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT AND WEDNESDAY...DRY/VFR. EAST WINDS.
* THURSDAY...DRY/VFR. SOUTHEAST WINDS.
* FRIDAY...CHANCE OF SHRA/TSRA. MVFR LIKELY. NORTHEAST WINDS.
* SATURDAY...CHANCE OF SHRA. MVFR POSSIBLE. NORTHEAST WINDS.
* SUNDAY...SLIGHT CHANCE OF SHRA/TSRA. NORTHEAST WINDS.

&&

.MARINE...
254 PM CDT

A HIGH PRESSURE RIDGE EXTENDING SOUTHEASTWARD OVER THE NORTHERN AND
CENTRAL PART OF LAKE MICHIGAN IS PRESERVING ONSHORE FLOW INTO THE
ILLINOIS AND INDIANA NEARSHORE INTO THIS EVENING. WIND SPEEDS WILL
DIMINISH THOUGH AND WAVES WHICH HAVE BEEN STEADY TODAY ARE EXPECTED
TO SLOWLY DROP AFTER DARK. THE RIDGE WILL EVER SO SLOWLY INCH SOUTH
WITH DIURNAL ONSHORE COMPONENTS IN ILLINOIS AND INDIANA FROM LAKE
BREEZES. A COLD FRONT IS EXPECTED TO DEVELOP OVER THE LAKE AHEAD OF
ANOTHER HIGH APPROACHING FROM THE NORTHWEST ON THURSDAY NIGHT...AND
MOVE SOUTHWARD OVER THE LAKE SOMETIME ON FRIDAY. HIGH PRESSURE THEN
LOOKS TO BRIEFLY MOVE OVER THE LAKE ON SATURDAY. THERE DO NOT APPEAR
TO BE ANY REGIMES FOR GALES THROUGH SATURDAY NOR SMALL CRAFT
ADVISORY CONDITIONS ALONG THE ILLINOIS AND INDIANA NEARSHORES
THROUGH THURSDAY.

MTF

&&

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

$$

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