Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 040721
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
221 AM CDT TUE AUG 4 2015

.SHORT TERM...
220 AM CDT

THROUGH WEDNESDAY...
HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE WEATHER TODAY AND
LIKELY THROUGH WEDNESDAY. THE GRADIENT REMAINS RATHER LIGHT EARLY
THIS MORNING...WITH MANY LOCATIONS SEEING A WEST WIND AROUND 5-
10MPH. THE RIDGE CENTER IS POSITIONED WEST OF THE FORECAST AREA
THROUGH THIS AFTERNOON...WHICH WILL KEEP A LIGHT GRADIENT
OVERHEAD. MIXING IS POISED TO INCREASE AGAIN THIS MORNING...AND
MAY PRODUCE SOME OCCASIONAL GUSTY WINDS TO 20MPH. AS THE DAY
PROGRESSES THE SFC RIDGE AXIS WILL BEGIN TO DRIFT EAST TOWARDS
NORTHERN IL/NORTHWEST IN. THIS WILL ALLOW WINDS TO DIMINISH LATE
THIS AFTERNOON/EARLY EVENING...AND MAY ALLOW A LIGHT ONSHORE FLOW
TO DEVELOP FOR AREAS ADJACENT TO LAKE MICHIGAN. HIGHS WILL WARM TO
NEAR SEASONAL CONDS IN THE LOWER 80S. CLOSER TO LAKE MICHIGAN
TEMPS MAY BE JUST A FEW DEGREES COOLER. TONIGHT THE SFC RIDGE AXIS
WILL BE OVERHEAD WITH LIGHT WINDS EXPECTED AGAIN. DRY WEATHER WILL
CONTINUE ALONG WITH MINIMAL CLOUD COVER...AND LOWS IN THE UPR 50S
TO LOW 60S.

WEDNESDAY WILL FEATURE THE SFC RIDGE CENTER BECOMING POSITIONED OVER
NORTHERN LOWER MICHIGAN...WITH A LIGHT ONSHORE FLOW DEVELOPING FOR
AREAS ADJACENT TO LAKE MICHIGAN. ELSEWHERE WITH THE RIDGE CENTER
DISPLACED NORTHEAST OF THE CWFA...WINDS WILL TURN SOUTHEASTERLY.
MOISTURE WILL BEGIN TO ADVECT NORTH TOWARDS THE OZARKS...HOWEVER
ENOUGH DRY AIR AND MID-LVL SUBSIDENCE SHOULD MAINTAIN DRY WEATHER
THROUGH WEDNESDAY ACROSS MUCH OF THE AREA. HIGHS WEDNESDAY WILL
AGAIN APPROACH THE LOW 80S...TO THE UPPER 70S CLOSER TO LAKE
MICHIGAN AND MAINLY FOR FAR NORTHEAST IL.

BEACHLER

&&

.LONG TERM...
326 PM CDT

TUESDAY THROUGH MONDAY...

QUIET WEATHER WILL PERSIST ON TUESDAY AS THE AREA REMAINS IN
BETWEEN THE STRONGER WESTERLIES USHERING IN MID LEVEL ENERGY TO
THE SOUTHWEST...AND STRONGER ENERGY WELL TO THE NORTH/NORTHEAST
TIED TO LARGE UPPER LEVEL CENTER. AFTER A PERIOD OF CAA...A MORE
NEUTRAL SETUP WILL BE IN PLACE ON TUESDAY AND WITH SUNNY SKIES
ONCE AGAIN IN PLACE...MOST LOCATIONS WILL OBSERVE HIGH TEMPS IN
THE LOW 80S. GENERALLY QUIET/DRY CONDITIONS WILL LIKELY PERSIST
INTO TUESDAY NIGHT...BUT AREAS ACROSS THE SOUTHERN CWA WILL SEE AN
INCREASE IN MID/HIGH LEVEL CLOUD COVER.

STILL SOME UNCERTAINTY IN PLACE WITH REGARDS TO POSSIBLE SYSTEM
DURING MIDWEEK...WITH GUIDANCE STILL VARYING FROM COMPLETELY DRY
CONDITIONS TO MORE WIDESPREAD PRECIP. MAIN TIME FRAME OF
UNCERTAINTY IS FROM WEDNESDAY INTO THURSDAY/THURSDAY NIGHT WITH
THE GFS/SREF STILL THE MORE AGGRESSIVE OF THE MODELS...BRINGING A
WETTER PATTERN ACROSS THE REGION. THE EXTENT OF THE NORTHERLY PUSH
OF THE STRONGER MID LEVEL ENERGY THIS WEEK WILL DICTATE OUR
WEATHER THIS WEEK AND FOR THE GOING FORECAST...HAVE MAINTAINED
HIGHEST CHANCE POPS ACROSS AREAS SOUTH OF INTERSTATE 80 WITH
SLIGHT CHANCE FURTHER NORTH DURING THIS TIME. INSTABILITY AXIS
LOOKS TO REMAIN ALONG/NEAR THE SOUTHERN CWA...AND HAVE ALSO
CONTINUED SLIGHT CHANCE THUNDER.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* WEST TO NORTHWEST WINDS ARND 6-8KT...INCREASING TO ARND 10KT
  AFTER DAYBREAK WITH GUSTS DEVELOPING AFT 15Z TO 17KT.

BEACHLER

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE WILL REMAIN CENTERED WEST OF NORTHERN IL/NORTHWEST
IN...ALLOWING A CONTINUED FEED OF LIGHT WINDS THROUGH DAYBREAK
FROM THE WEST TO SLIGHTLY NORTHWEST. MIXING WILL INCREASE MID TO
LATE MORNING...AND ALLOW SOME GUSTS TO DEVELOP UP TO 18KT. THIS
SHOULD BE STRONG ENOUGH WINDS TO PREVENT A LAKE BREEZE FROM
PUSHING INLAND. WINDS DIMINISH SHORTLY AFTER SUNSET...BUT REMAIN
WESTERLY ARND 6-10KT. DRY AIR WILL CONTINUE TO LIMIT THE CLOUD
COVER TODAY...WITH ONLY A FEW CIRRUS CLOUDS FLOATING OVERHEAD.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

WEDNESDAY...SLIGHT CHANCE SHRA IN THE EVENING...OTHERWISE VFR.
WINDS BECOMING EAST.

THURSDAY...CHANCE SHRA/SLIGHT CHANCE TSRA...OTHERWISE VFR. EAST-
NORTHEAST WINDS.

FRIDAY...CHANCE SHRA/TSRA...OTHERWISE VFR. EAST-NORTHEAST WINDS.

SATURDAY...PRIMARILY VFR.

SUNDAY...PRIMARILY VFR. SLIGHT CHANCE SHRA/TSRA AT NIGHT.

RC

&&

.MARINE...
444 PM CDT

WESTERLY WINDS IN PLACE THIS AFTERNOON AND EVENING WILL BECOME
MORE NORTHERLY WITH LOW PRESSURE TO THE NORTHEAST...AND HIGH
PRESSURE EXTENDING FROM THE NORTHERN PLAINS THROUGH THE OHIO
VALLEY. THIS HIGH WILL SPREAD OVER THE WESTERN GREAT LAKES THIS
EVENING AND SHIFT EAST OF THE LAKE BY MID WEEK...WHILE WINDS ARE
EXPECTED TO REMAIN RELATIVELY LIGHT DURING THIS PERIOD. GUIDANCE
VARIES SIGNIFICANTLY WITH REGARDS TO SURFACE PATTERN FROM MID WEEK
TO THE END OF THE WORK WEEK...WITH CHANGES TO CURRENT WIND
SPEED/DIRECTION FORECAST LIKELY IN THE COMING DAYS.

RODRIGUEZ

&&

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

$$

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