Area Forecast Discussion
Issued by NWS Chicago, IL

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FXUS63 KLOT 170531
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1231 AM CDT THU APR 17 2014

.DISCUSSION...
331 PM CDT

MAIN FORECAST CONCERNS/CHALLENGES ARE WITH PRECIP AND TEMP TRENDS
THURSDAY INTO FRIDAY...AND THEN WITH A DEFINITE WARMING TREND THIS
WEEKEND INTO NEXT WEEK.

WITH VORT MAX SHIFTING EAST/NORTHEAST ACROSS THE CENTRAL CONUS
THIS AFTERNOON...ATTENDANT SURFACE LOW CONTINUES TO SLOWLY SHIFT
EAST THROUGH EASTERN NEBRASKA AND IOWA THIS AFTERNOON AS A FAIRLY
TIGHT PRESSURE GRADIENT HAS ESTABLISHED ITSELF ACROSS THE CWA.
SOUTH TO SOUTHEAST HAVE PICKED UP THIS AFTERNOON WITH SOME
LOCATIONS ACROSS NORTHERN ILLINOIS GUSTING UP TO 30 TO 35 MPH. AS
THIS SURFACE LOW PUSHES NORTHEAST THROUGH IOWA AND INTO SOUTHERN
WISCONSIN TONIGHT...EXPECT WINDS TO TURN MORE SOUTH/SOUTHWEST
WHILE DIMINISHING BUT STILL GUSTING TO AROUND 25 TO 30 MPH FOR A
TIME THIS EVENING. BEST FORCING REMAINS WELL NORTH OF THE CWA AS
THIS VORT MAX AND LOW MOVE ACROSS THE REGION...WITH THE CWA
REMAINING DRY TONIGHT. MOST GUIDANCE IN AGREEMENT WITH A DRY
FORECAST TONIGHT...BUT STILL THINK THERE COULD BE A BRIEF LIGHT
SHOWER OR AT LEAST SOME SPRINKLES RIGHT ALONG THE
ILLINOIS/WISCONSIN BORDER WITH THE WAA PUSH OVERNIGHT. HAVE NOT
MADE MENTION OF THIS WITH LOWER CONFIDENCE AT THIS POSSIBILITY AND
DUE TO THE FACT THAT IF IT WERE TO OCCUR...ANTICIPATE ANYTHING
THAT FALLS TO ONCE AGAIN BE ON THE LIGHTER SIDE AND BRIEF. EXPECT
CURRENT CLEAR OR PARTLY CLOUDY SKIES IN PLACE TO SEE SOME INCREASE
IN CLOUD COVER TONIGHT...WITH A PERIOD OF CLOUDY SKIES LATER
TONIGHT ESPECIALLY OVER THE NORTHERN HALF OF THE CWA WITH OTHER
LOCATIONS SOUTH TO BE MORE PARTLY CLOUDY.

SURFACE LOW WILL CONTINUE NORTHEAST ON THURSDAY WEAKENING
SIGNIFICANTLY BY MID DAY AS UPPER SUPPORT IS QUICKLY LOST.
PERSISTENT WAA AND SOUTH/SOUTHWEST FLOW SHOULD ALLOW FOR SURFACE
TEMPS TO RISE INTO THE UPPER 50S AND LOWERS 60S THURSDAY...EVEN
WITH PARTLY CLOUDY/PARTLY SUNNY SKIES IN PLACE. INITIAL DRY
CONDITIONS AS SURFACE TROUGH/FRONT PUSH THROUGH THURSDAY WILL BE
REPLACE WITH AN INCREASE IN RAIN CHANCES LATER IN THE DAY AS
MID/UPPER LEVEL TROUGH SWING ACROSS THE REGION. IT DOES APPEAR AS
THIS RAIN WILL ONCE AGAIN BE ON THE LIGHTER SIDE AND STAY CONFINED
TO THE SOUTHEAST TWO THIRDS OF THE CWA...AND HAVE MAINTAINED HIGH
CHANCE POPS THURSDAY NIGHT. EXPECT ANY LINGERING RAIN TO QUICKLY
EXIT FRIDAY MORNING AS DRIER/COOLER AIR MOVES ACROSS THE
CWA...WITH SLIGHTLY COOLER TEMPS ESPECIALLY NEAR THE LAKE.
ALTHOUGH...IT DOES APPEAR THAT AN OVERALL WARMING TREND WILL START
THIS WEEKEND AND LIKELY CONTINUE INTO NEXT WEEK. HAVE CONTINUED
THIS WARMING TREND BY MAKING SLIGHT UPWARD ADJUSTMENTS ABOVE
GUIDANCE. WITH THIS WARMING TREND A LIKELY INCREASE IN MOISTURE
WILL OCCUR AS WELL AND AS PRECIP CHANCES ARRIVE EARLY NEXT
WEEK...THERE WILL ALSO BE POSSIBILITIES FOR THUNDER. CONFIDENCE IS
LOW WITH THIS POSSIBILITY AND SO HAVE LEFT OUT ANY MENTION OF
THUNDER AT THIS TIME...BUT COULD SEE A TREND TOWARDS THIS SOLUTION
POSSIBLE OVER THE NEXT COUPLE OF DAYS.

RODRIGUEZ

&&

.AVIATION...

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

* SOUTHEAST WINDS VEERING TO WEST BY MIDDAY THURSDAY...THEN NORTH
  TO NORTHEAST LATE THURSDAY EVENING.
* POTENTIAL FOR LOW LEVEL WIND SHEAR OVERNIGHT INTO THURSDAY MORNING.

BMD

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

LOW PRESSURE LIES OVER FAR NORTHEASTERN IOWA TONIGHT AND WILL FILL
AS IT LIFTS TO NORTHERN WISCONSIN BY MID MORNING THURSDAY. A COLD
FRONT STRETCHES SOUTH INTO CENTRAL MISSOURI. AHEAD OF THE
FRONT...STRONG LOW-MID LEVEL WINDS COULD RESULT IN LLWS...WITH THE
BEST CHANCES AT RFD WHICH WILL BE CLOSER IN PROXIMITY TO THE LOW
LEVEL JET. THE COLD FRONT WILL MOVE ACROSS NORTHERN ILLINOIS LATE
MORNING INTO EARLY AFTERNOON WITH PRECIP ALONG THE FRONT FAIRLY
UNLIKELY. WINDS TURN WSW BEHIND THE FRONT AND EVENTUALLY
NORTHWESTERLY IN THE EVENING. WINDS WILL CONTINUE TO VEER TO THE
NORTHEAST THURSDAY NIGHT.

BMD


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

* MEDIUM CONFIDENCE IN WIND DIRECTION/TIMING CHANGES IN DIRECTION.
* LOW CONFIDENCE IN LLWS.

BMD

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

FRIDAY...VFR. WX NIL.

SATURDAY...VFR. WX NIL.

SUNDAY...CHC RAIN. MVFR POSSIBLE.

MONDAY...CHC RAIN EARLY. OTRW...VFR/WX NIL.

TUESDAY...VFR. WX NIL.

WEDNESDAY...SLIGHT CHC RAIN. MVFR POSSIBLE.

KREIN

&&

.MARINE...
203 PM CDT

LOW PRESSURE...CURRENTLY ACROSS FAR WESTERN IOWA...WILL SHIFT
NORTHEASTWARD ACROSS THE UPPER LAKES REGION BY LATE
THURSDAY...WHILE WEAKENING. THIS WILL RESULT IN A CONTINUATION OF
THE SOUTH-SOUTHEASTERLY WINDS ACROSS THE LAKE TONIGHT AROUND 30 KT
RANGE. HOWEVER...AS A WEAK FRONTAL BOUNDARY MOVES ACROSS THE LAKE ON
THURSDAY...THE WINDS ABATE AND BECOME WEST-NORTHWESTERLY BY THURSDAY
EVENING. GENERALLY LIGHT NORTHERLY FLOW IS EXPECTED FRIDAY AND INTO
EARLY SATURDAY AS A WEAK SURFACE RIDGE OF HIGH PRESSURE BUILDS OVER
THE LAKE. THE WINDS LOOK TO INCREASE AGAIN OUT OF THE
SOUTH-SOUTHEAST LATER SATURDAY/SATURDAY EVENING AS THIS SURFACE
RIDGE SHIFTS EAST OF THE LAKES AND ANOTHER LOW TAKES SHAPE ACROSS
THE PLAINS.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 4 AM THURSDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 AM THURSDAY.

&&

$$

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