253
FXUS63 KLOT 192334
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
634 PM CDT SUN APR 19 2026
KEY MESSAGES
- FROST/FREEZE CONDITIONS ARE EXPECTED OUTSIDE OF CHICAGO LATE
TONIGHT INTO MONDAY MORNING.
DISCUSSION
ISSUED AT 255 PM CDT SUN APR 19 2026
CONVECTIVE SHOWERS TIED TO BOTH A SHARP MID-LEVEL TROUGH AND
SURFACE COLD FRONT HAVE PRODUCED RAIN, SNOW, GRAUPEL AND SOME
LIGHTNING ACROSS ACROSS NORTHERN ILLINOIS OVER THE PAST COUPLE
HOURS. THE INTENSITY OF THESE SHOWERS SHOULD CONTINUE THROUGH
LATE AFTERNOON AS THEY TRACK SOUTHEAST BEFORE WANING WITH THE
LOSS OF DAYTIME HEATING.
A BROAD SURFACE HIGH WILL THEN EDGE SOUTHEASTWARD OVER THE AREA
OVERNIGHT INTO MONDAY MORNING. BESIDE A LOW CHANCE FOR SOME
SHALLOW LAKE EFFECT CLOUDS DRIFTING OVER FAR NORTHEAST ILLINOIS
OVERNIGHT, MOSTLY CLEAR TO CLEAR SKIES ARE EXPECTED. VERY DRY
AIR HIGHLIGHTED BY CURRENT DEW POINTS IN THE MID TEENS OVER
CENTRAL WISCONSIN AND PWATS UNDER 0.25 INCH COMBINED WITH
LIGHT/CALM WINDS WILL ALLOW FOR EFFICIENT RADIATIONAL COOLING
TONIGHT. THE CURRENT FREEZE WARNING FOR ALL BUT CENTRAL COOK
COUNTY REMAINS ON TRACK. HAVE OPTED TO ALSO INCLUDE A FROST
ADVISORY FOR CENTRAL COOK COUNTY FOR MAINLY THE NEAR WEST
SUBURBS. IT IS POSSIBLE THAT THE DRY AIR LIMITS FROST
DEVELOPMENT EVEN WITH TEMPS IN THE 32-35F RANGE, BUT IT SEEMS
PRUDENT TO INCLUDE A HEADLINE AS WE ARE NOW WELL INTO THE
GROWING SEASON.
THE HIGH PRESSURE WILL BRING MOSTLY SUNNY SKIES, LIGHT WINDS
AND HIGH TEMPS IN THE 50S (40S NEAR THE LAKE) FOR MONDAY.
INCREASING SOUTHWEST FLOW BEHIND THE DEPARTING RIDGE WILL YIELD
MUCH WARMER CONDITIONS WITH HIGHS IN THE 70S ON TUESDAY.
HOWEVER, A BACKDOOR COLD FRONT BELOW A SMALL MID-LEVEL WAVE
CROSSING THE AREA LATE TUESDAY AFTERNOON INTO THE EVENING MAY
PROVIDE SUFFICIENT ASCENT TO GENERATE AN AXIS OF SHOWERS AND
PERHAPS A FEW STORMS. SOMEWHAT LIMITED LOW-LEVEL MOISTURE AND
EXISTING CAPPING UNDER THE EDGE OF AN EML SHOULD LIMIT
THUNDERSTORM COVERAGE.
RIDGING WILL BUILD BACK INTO THE AREA BY THURSDAY, WITH ANOTHER
ROUND OF SHOWERS AND STORMS, SOME POTENTIALLY STRONG, THURSDAY
NIGHT AND FRIDAY.
KLUBER
AVIATION /00Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 633 PM CDT SUN APR 19 2026
FORECAST CONCERNS INCLUDE...
WIND SHIFT TO NORTHEAST THIS EVENING.
WIND DIRECTIONS MONDAY.
CHANCE OF SHOWERS EARLY THIS EVENING.
A LAKE BREEZE BOUNDARY IS CURRENTLY MOVING WEST THROUGH ORD/MDW,
SHIFTING WINDS TO THE NORTHEAST. SPEEDS 10-12KT WILL BE POSSIBLE
FOR THE NEXT HOUR OR SO. NORTHWESTERLY WINDS WILL CONTINUE WEST
OF THIS BOUNDARY THROUGH SUNSET AND THEN SPEEDS WILL DIMINISH
THROUGH THE EVENING, BECOMING LIGHT AND VARIABLE OR CALM
OVERNIGHT. WIND DIRECTIONS ARE CHALLENGING ON MONDAY AND MAY
EVENTUALLY FAVOR SOUTH/SOUTHWEST FROM LATE MORNING THROUGH MID
AFTERNOON AND THEN SLOWLY TURN BACK SOUTH/SOUTHEAST BY EARLY
EVENING. A LAKE BREEZE IS EXPECTED BUT ITS UNCERTAIN HOW FAR
INLAND IT WILL MOVE. IF IT WERE TO MAKE IT TO ORD/MDW, A MORE
EASTERLY DIRECTION WOULD BE EXPECTED BY EARLY MONDAY EVENING.
THERE REMAINS A LOW CHANCE FOR A FEW SHOWERS EARLY THIS EVENING,
MAINLY OVER LAKE MICHIGAN AND INTO NORTHWEST IN. EXPECTED
COVERAGE IS TOO LOW FOR ANY MENTION WITH THIS FORECAST. CMS
LOT WATCHES/WARNINGS/ADVISORIES
IL...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM CDT MONDAY FOR
ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-
ILZ013-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-
ILZ103-ILZ105-ILZ106-ILZ107-ILZ108.
FROST ADVISORY FROM 2 AM TO 9 AM CDT MONDAY FOR ILZ104.
IN...FREEZE WARNING FROM MIDNIGHT CDT /1 AM EDT/ TONIGHT TO 9 AM
CDT /10 AM EDT/ MONDAY FOR INZ001-INZ002-INZ010-INZ011-
INZ019.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE IL
AND IN NEARSHORE WATERS.
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