479
FXUS63 KLOT 150745
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
245 AM CDT MON SEP 15 2025
KEY MESSAGES
- WARM AND DRY CONDITIONS ARE EXPECTED THROUGH THE WORK WEEK.
- PERIODIC SHOWER AND THUNDERSTORM CHANCES RETURN TOWARD THE END
OF THE WEEK (20-30%).
DISCUSSION
ISSUED AT 245 AM CDT MON SEP 15 2025
AN OVERALL QUIESCENT PATTERN IS IN PLACE ACROSS THE REGION WITH
AMPLIFIED UPPER RIDGING ACROSS THE WESTERN GREAT LAKES REGION
ATOP A CLOSED UPPER LOW IN THE SOUTHEAST (A PSEUDO-REX BLOCK
PATTERN). THIS WILL ALLOW UNSEASONABLY WARM TEMPERATURES TO
PREVAIL THROUGH THE REST OF THE WORK WEEK WITH HIGH TEMPERATURES
IN THE 80S TO NEAR 90 (WARMEST TOWARD WESTERN AND CENTRAL
ILLINOIS). RELATIVELY WEAK SURFACE FLOW AMIDST EXPANSIVE SURFACE
HIGH PRESSURE SHOULD ALLOW DAILY LAKE BREEZES TO PUSH INLAND
HOLDING TEMPERATURES MAINLY IN THE 70S NEAR THE LAKESHORE. THIS
SHOULD ALSO HELP KEEP ANY SHOWER/STORM ACTIVITY WEST OF THE
LOCAL AREA FOR THE MAJORITY OF THE WORK WEEK.
ENSEMBLE GUIDANCE HAS ALSO TRENDED A BIT SLOWER WITH THE BREAK
DOWN OF THE UPPER RIDGE/BLOCKING PATTERN LATER IN THE WEEK WITH
MOST OF THE AREA REMAINING DRY THROUGH THE DAY ON FRIDAY AND
FURTHER SLOWING COULD OCCUR WITH LATER UPDATES. EVENTUALLY THE
WESTERN TROUGH (AND/OR POTENTIAL CUT-OFF LOW) WILL SHIFT EAST
TOWARD AND OVER THE AREA LEADING TO PERIODIC SHOWER AND
THUNDERSTORM CHANCES OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS
WILL BE PAIRED WITH COOLER MORE SEASONABLE TEMPERATURES IN THE
70S.
PETR
AVIATION /06Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 1217 AM CDT MON SEP 15 2025
NO MAJOR FORECAST CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD
AS A DOME OF HIGH PRESSURE WILL REMAIN PARKED OVER THE GREAT
LAKES. THEREFORE, EXPECT MOSTLY CLEAR SKIES WITH THE OCCASIONAL
PASSING CIRRUS CLOUD AND LIGHT 5-8 KT WINDS. WIND DIRECTIONS
WILL GENERALLY BE OUT OF THE EAST THROUGH THE PERIOD, BUT
DIRECTIONS MAY BECOME SLIGHTLY SOUTH OF EAST TONIGHT.
ADDITIONALLY, THERE IS THE POTENTIAL FOR A LAND BREEZE TO
DEVELOP MONDAY NIGHT WHICH MAY RESULT IN NORTH-NORTHEAST WINDS
AT ORD AND MDW.
FINALLY, THERE IS A NON-ZERO CHANCE (~5%) FOR SOME PATCHY FOG TO
DEVELOP TONIGHT. HOWEVER, WITH DEW POINTS EXPECTED TO BE
LOWERING THROUGH THE NIGHT CONFIDENCE ON FOG OCCURRING IS VERY
LOW AND THUS HAS BEEN LEFT OUT OF THE TAFS FOR NOW.
YACK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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