Area Forecast Discussion
Issued by NWS Chicago, IL

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000
FXUS63 KLOT 252336
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
636 PM CDT SAT APR 25 2015

.SHORT TERM...
259 PM CDT

THROUGH MONDAY...

MAIN FORECAST CHALLENGES/CONCERNS ARE WITH LINGERING SHOWERS LATE
THIS AFTERNOON INTO THE EARLY EVENING ACROSS THE SOUTHEAST TWO
THIRDS OF THE CWA...AND THEN WITH QUIETER WEATHER FOR THE
REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK.

UPPER LEVEL LOW CONTINUES TO MOVE THROUGH THE REGION THIS
AFTERNOON...AND BEGINNING TO OPEN UP AT THIS TIME. THIS SHOULD
HELP TO KICK THIS OFF TO THE EAST...WITH IT THEN LIKELY BEING
ABSORBED INTO A MUCH LARGER UPPER LEVEL SYSTEM OVER THE EASTERN
CONUS. WITH THE DEPARTURE OF THIS FEATURE AND ASSOCIATED SURFACE
LOW...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. ANY REMAINING
PRECIP ACROSS THE CWA THIS AFTERNOON WILL DIMINISH FROM NORTHWEST
TO SOUTHEAST THROUGH EARLY EVENING...WITH DRY CONDITIONS AND
CLEARING SKIES THEN EXPECTED OVERNIGHT. COLDER CONDITIONS IN THE
LOW TO MID 30S ARE EXPECTED TONIGHT BUT WITH FROST NOT ANTICIPATED
AT THIS TIME...AS THE CWA WILL REMAIN ON THE FRINGE OF THIS HIGH
WITH WINDS REMAINING ELEVATED THROUGHOUT THE NIGHT.

WITH THE LARGE UPPER LEVEL SYSTEM REMAINING TO THE EAST AND WITH
UPPER LEVEL WEAKER FLOW/RIDGING OVER MUCH OF THE CENTRAL
CONUS...SURFACE HIGH WILL REMAIN SITUATED SUNDAY INTO
MONDAY...SLOWLY BUILDING. ALTHOUGH DRY CONDITIONS AND SUNNY SKIES
ARE EXPECTED SUNDAY...TEMPS WILL STILL LIKELY BE BELOW NORMAL AND
ESPECIALLY NEAR THE LAKE WITH ONSHORE FLOW. ENERGY LOOKS TO
CONTINUE TO WRAP AROUND THIS SYSTEM TO THE EAST WITH A STRONGER
PIECE OF ENERGY LIKELY MOVING SOUTH THROUGH THE CENTRAL GREAT
LAKES SUNDAY NIGHT INTO MONDAY MORNING. HOWEVER...AT THIS
TIME...IT LOOKS TO ONLY PROVIDE AN INCREASE IN CLOUD COVER OVER AT
LEAST THE EASTERN HALF OF THE CWA.

RODRIGUEZ

&&

.LONG TERM...
259 PM CDT

MONDAY NIGHT THROUGH SATURDAY...

SYSTEM TO THE EAST APPEARS TO BEGIN TO TAKE ON A MORE EASTWARD
MOVEMENT BY THE START OF THE EXTENDED PERIOD WITH ANOTHER UPPER
LOW EXPECTED TO SLOWLY SPIN OVER THE CENTRAL/SOUTHERN
PLAINS...WHILE WEAK RIDGING OCCURS OVER THE REGION. GUIDANCE IS
SHOWING SHORTWAVE ENERGY DROPPING EAST SOUTHEAST THROUGH THE UPPER
MIDWEST LATE TUESDAY TRYING TO INCH CLOSER TO THE AREA...BUT IT
LOOKS LIKE THIS WILL SLIDE JUST TO THE NORTH/NORTHEAST INTO
WEDNESDAY. SOME SLIGHT POTENTIAL FOR LIGHT RAIN LATER IN THE DAY
ON WEDNESDAY BUT UPPER LEVEL RIDGING WITH DRY CONDITIONS AND
WARMING APPEAR TO BE THE TREND THROUGH THE REST OF THE WORK
WEEK...WITH ABOVE NORMAL TEMPS BECOMING MORE LIKELY.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* PATCHY MVFR LAYER 2000-2500 FT MAINLY JUST TO WEST/SOUTH ERODING
  QUICKLY WITH RISING VFR CIGS THIS EVENING. PATCHY -RA/SHRA JUST
  OFF TO SOUTH ALSO ENDING EARLY.

* WINDS BACKING 020-030 DEG THIS EVENING...GENERALLY 10-15 KTS
  AND SLOWLY DIMINISHING.

* NORTH-NORTHEAST WINDS GUSTING 15-20 KT SUNDAY AFTERNOON.

RATZER

//DISCUSSION...UPDATED 00Z...

SURFACE LOW PRESSURE WAS MOVING EAST THROUGH THE LOWER OHIO
VALLEY EARLY THIS EVENING...WITH LOCAL TERMINALS ALONG NORTHERN
FRINGE OF PRECIP/LOWER CEILINGS ASSOCIATED WITH THIS SYSTEM.
SURFACE WINDS ARE BEGINNING TO BECOME MORE NORTH-NORTHEAST
HOWEVER...WITH MUCH DRIER AIR SPREADING TOWARD THE REGION FROM THE
NORTH. RADAR TRENDS INDICATE LINGERING SHOWERS TO AFFECT ONLY KGYY
EARLY THIS EVENING...WITH SOME PATCHY 2000-2500 FT MVFR CIGS
INITIALLY AS FAR NORTH AS DPA-ORD-PWK EXPECTED TO ERODE QUICKLY
AS DRIER AIR ARRIVES. VFR CIGS EXPECTED TO RISE/ERODE AS WELL
MID-LATE EVENING. DRY AIR AND GENERALLY SKC CONDITIONS EXPECTED
LATER TONIGHT THROUGH SUNDAY.

FORECAST AREA WILL REMAIN WITHIN SOUTHERN PERIPHERY OF HIGH
PRESSURE RIDGE OVER UPPER MIDWEST THROUGH THE PERIOD. THIS WILL
MAINTAIN NORTH-NORTHEAST WINDS...WITH GRADIENT REMAINING STRONG
ENOUGH KEEP WINDS 10-15 KTS...WITH 15-20 KT GUSTS SUNDAY
AFTERNOON. GRADIENT WEAKENS MORE SIGNIFICANTLY SUNDAY EVENING
ALLOWING WINDS TO DIMINISH BELOW 10 KTS.

RATZER


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* MEDIUM-HIGH IN TIMING IMPROVING CIG TRENDS THIS EVENING. HIGH
  CONFIDENCE IN ANY MVFR CIGS BEING BRIEF EARLY.

* HIGH ALL OTHER ELEMENTS.

RATZER

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

MONDAY AND TUESDAY...VFR. NORTH-NORTHEAST WINDS.

WEDNESDAY...SLGT CHC -SHRA...PRIMARILY VFR. NORTH-NORTHEAST WINDS.

THURSDAY...VFR. NORTH-NORTHEAST WINDS.

FRIDAY...VFR. SOUTHWEST WINDS.

RATZER

&&

.MARINE...
137 PM CDT

MODERATE NORTHERLY FLOW WILL PERSIST THROUGH MONDAY...PARTICULARLY
SOUTHERN PORTIONS OF THE LAKE AS GRADIENT REMAINS RATHER TIGHT
BETWEEN HIGH OVER CANADA AND LOW PASSING WELL SOUTH OF THE LAKES.
WEAK GRADIENT OVER THE LAKE THROUGH MUCH OF THE REMAINDER OF THE
UPCOMING WORK WEEK WITH WINDS DOMINATING BY LAKE/LAND BREEZE
CIRCULATIONS.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 10 AM MONDAY.

&&

$$

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