Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 132016
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
316 PM CDT SAT SEP 13 2014

.DISCUSSION...
315 PM CDT

MAIN FORECAST CONCERNS/CHALLENGES ARE WITH ANOTHER COLD NIGHT
TONIGHT...WITH FROST POSSIBLE ACROSS THE CWA.

QUIET BUT COOL AFTERNOON AS EARLY MORNING STRATUS LINGERED AND
THEN EXPANDED WITH STRATOCU STILL PRESENT OVER THE CWA. CONTINUED
CAA AND THIS CLOUD COVERED LIMITED DAYTIME WARMING TODAY WITH MOST
LOCATIONS ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA NOT
RISING OUT OF THE 50S TODAY. ANY LINGERING CLOUD COVER THIS
AFTERNOON WILL DIMINISH THROUGH THE EVENING WITH MOSTLY CLEAR
SKIES THEN EXPECTED TONIGHT. WITH HIGH PRESSURE CONTINUING TO
SHIFT EAST THIS EVENING AND THEN REMAINING SITUATED OVER THE CWA
TONIGHT INTO SUNDAY MORNING...SETUP FOR ANOTHER COLD NIGHT WILL BE
IN PLACE. SOME WEAK WAA IS STILL ANTICIPATED TONIGHT AS WINDS
BECOME MORE SOUTHERLY...BUT THIS SLIGHT WARMING MAY ARRIVE TOO
LATE TO HAVE AN OVERALL IMPACT ON LOW TEMPS TONIGHT. MADE ONLY
MINOR ADJUSTMENTS TO MIN TEMPS TONIGHT MAINTAINING MID TO UPPER
30S ACROSS NORTH CENTRAL ILLINOIS BUT DID LOWER TEMPS TO THE UPPER
30S OVER AREAS IN EAST CENTRAL ILLINOIS AND NORTHWEST INDIANA...AS
WELL AS EXPANDED MENTION OF FROST IN THE GRIDS. WITH WARMER
SURFACE TEMPS STILL IN PLACE AS WELL AS HIGHLY SATURATED
CONDITIONS OBSERVED OVER THE ENTIRE AREA...ANY FROST DEVELOPMENT
SHOULD REMAIN LIMITED TONIGHT AND HAVE NOT ISSUED ANY HEADLINES
THIS AFTERNOON BUT WILL CONTINUE MENTION IN THE ZONES/HWO.

SUNNY AND DRY CONDITIONS WITH SLIGHTLY WARMER TEMPS IN THE LOW TO
MID 60S EXPECTED ON SUNDAY...AS THIS HIGH PROGRESSES TO THE EAST.
INCREASING CLOUD COVER WILL BE OBSERVED SUNDAY NIGHT AND
ESPECIALLY TOWARDS EARLY MONDAY MORNING...WITH CHANCES FOR SHOWERS
INCREASING ACROSS NORTHERN ILLINOIS DURING THIS TIME. CURRENT
SHORT WAVE PROGRESSING EAST THROUGH THE NORTHERN PLAINS WILL
CONTINUE EAST TONIGHT THROUGH SUNDAY NIGHT AND EARLY MONDAY
MORNING...WITH ASSOCIATED SURFACE LOW/TROUGH DROPPING EAST
SOUTHEAST TOWARDS THE REGION. THIS WILL LIKEWISE KEEP MOST OF THE
PRECIP TO THE WEST AND NORTHWEST INTO EARLY MONDAY MORNING BUT
WITH PRECIP CHANCES INCREASING QUICKLY THROUGH MONDAY. A SECOND
AND STRONGER SHORTWAVE WILL MOVE IN BEHIND THE FIRST WAVE AND DIVE
SOUTHEAST TOWARDS THE CWA ON MONDAY...WITH SURFACE TROUGH PUSHING
THROUGH THE CWA. EXPECT AREA OF SHOWERS TO THEN MOVE THROUGH THE
CWA ON MONDAY WITH GUIDANCE IN AGREEMENT OF OVERALL TRENDS...AND
HAVE MAINTAINED LIKELY POPS IN THE GRIDS. PRECIP WILL THEN QUICKLY
DEPART MONDAY EVENING AS HIGH PRESSURE BUILDS BACK OVERHEAD.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* PATCHY CIGS ARND 3KFT WILL CONTINUE TO THIN AND BECOME NEARLY
  SKC BY 00Z.

* POSSIBLE LGT NE TURN TO WIND DIR THIS AFTN WITH SPEEDS ARND
  6-8KT.

* WINDS WILL DIMINISH TO ARND 3KT AND BECOME VRB AFT 00Z THRU
  OVERNIGHT.

BEACHLER

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

PATCHY MVFR CIGS HAVE STRUGGLED TO LIFT OUT OF NORTHERN
IL/NORTHWEST IN AIRFIELDS...AND WITH COOL AIR ALOFT STEADILY
ADVECTING INTO THE REGION THIS APPEARS TO BE AIDING IN THE LOW
CIGS CONTINUEING. FORTUNATELY HIGH PRESSURE IS BUILDING IN FROM
THE WEST AND THIS APPEARS TO BE THINNING THE CLOUDS. BASED ON THE
TREND IT APPEARS BY 20Z THE BKN CIGS WILL THIN ENOUGH TO BECOME A
FEW/SCT DECK. THEN AS DRY AIR ALOFT CONTINUES TO SLIDE
OVERHEAD...SKIES SHUD BECOME NEARLY SKC THRU MUCH OF THE
OVERNIGHT. A THIN CIRRUS SHIELD IS POSSIBLE...OTHERWISE FEEL SKC
WAS APPROPRIATE. THERE MAY BE SOME PATCHY FOG OVERNIGHT...ALTHOUGH
CONFIDENCE IS HIGHER THAT THIS WILL REMAIN OUT OF THE TAF SITES.
WINDS MAY ALSO BECOME CALM FOR A GOOD PORTION OF THE OVERNIGHT
HOURS...BUT ALSO AT TIMES COULD VARY WITH DIRECTION. HIGH PRESSURE
THEN SLIDES EAST SUN MORNING...WITH WINDS SHIFTING SOUTHWEST WITH
SPEEDS ARND 6-9KT BY MID-MORNING SUN. SOME FAIR WEATHER CLOUDS ARE
POSSIBLE BY LATE MORNING SUN...OTHERWISE VFR CONDS.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

BEACHLER

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

SUNDAY NIGHT...VFR.
MONDAY...SHOWERS LIKELY.
TUESDAY THROUGH FRIDAY...VFR.

BMD

&&

.MARINE...

235 PM...A LARGE AREA OF HIGH PRESSURE CENTERED OVER IL WILL MOVE
EAST ACROSS THE SOUTHERN LAKES AND OHIO VALLEY TONIGHT. NORTHERLY
WINDS ON THE SOUTH END OF THE LAKE WILL BECOME LIGHT AND VARIABLE
THIS EVENING THEN SOUTHERLY OVERNIGHT. WEAK LOW PRESSURE OVER
SOUTHERN MANITOBA WILL MOVE NORTHEAST ACROSS ONTARIO TONIGHT AND
SUNDAY AND THE GRADIENT WILL TIGHTEN ON THE BACK SIDE OF THE HIGH
PRESSURE. SOUTHERLY WINDS WILL STEADILY INCREASE SUNDAY MORNING
WITH A PERIOD OF 20-25 KTS EXPECTED OVER THE NORTHERN HALF OF THE
LAKE SUNDAY AFTERNOON INTO SUNDAY EVENING. A TRAILING COLD FRONT
WILL MOVE ACROSS THE LAKE SUNDAY NIGHT INTO MONDAY TURNING WINDS
WESTERLY AND THEN EVENTUALLY NORTHWESTERLY MONDAY NIGHT. ANOTHER
AREA OF HIGH PRESSURE WILL MOVE FROM THE PLAINS MONDAY TO THE
SOUTHERN LAKES AND OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 10 PM SATURDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 10 PM SATURDAY.

LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 PM SATURDAY.

&&

$$

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