600
FXUS63 KLOT 050822
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
322 AM CDT THU JUN 5 2025
KEY MESSAGES
- AREAS OF DENSE FOG EARLY THIS MORNING ALONG THE I-80 CORRIDOR
IN ILLINOIS AND POSSIBLY ALONG THE IMMEDIATE LAKESHORE AS
WELL.
DISCUSSION
ISSUED AT 322 AM CDT THU JUN 5 2025
THROUGH FRIDAY:
EARLY MORNING GOES NIGHTTIME RGB IMAGERY SHOWS AN AREA OF FOG
DEVELOPING ROUGHLY ALONG THE I-80 CORRIDOR FROM THE SOUTHWEST
CHICAGO SUBURBS WEST INTO NORTH CENTRAL IL. KVYS AND KJOT ARE
BOTH DOWN TO M1/4SM, THOUGH ADMITTEDLY KJOT AWOS IS IN A LOW
SPOT THAT FREQUENTLY FOGS. WEBCAMS ALONG I-80 IN WILL COUNTY DO
SHOW DENSE FOG AS WELL, SO OPTED TO HOIST A DENSE FOG ADVISORY
UNTIL 9 AM THIS MORNING. SUNRISE IS ONLY A COUPLE OF HOURS AWAY
AND WITH THE HIGH SUN ANGLE I'D ANTICIPATE THIS DENSE FOG TO
BURN OFF WITHIN A COUPLE OF HOURS OF SUNRISE.
ALSO SEEING SOME DENSE MARINE FOR DEVELOP WITH WEBCAMS SHOWING
IT OOZING INLAND JUST A BIT IN SPOTS ALONG THE IL SHORELINE. THE
INLAND EXTENT IS VERY LIMITED AND ONLY SEEMS TO BE SPREADING
INLAND SO FAR IN VERY LOCALIZED SPOTS, SO GOING TO HOLD OFF ON A
DENSE FOG ADVISORY NEAR THE LAKE FOR NOW. IF THE MARINE FOG
PERSISTS INTO THE LAKE MORNING OR AFTERNOON, THEN IT IS POSSIBLE
THAT THE FOG COULD REACH JUST SLIGHTLY INLAND AS ONSHORE FLOW
PICKS UP DIURNALLY, THOUGH FOG WILL BE FIGHTING HIGH SUN ANGLE
AND LIKELY CONFINED TO AREAS WITHIN A QUARTER MILE OF SHORE.
OTHERWISE, FAIRLY BENIGN WEATHER IS EXPECTED TODAY THROUGH
FRIDAY. THE FRONTAL BOUNDARY HAS PUSHED WELL SOUTH OF OUR AREA
AND MAY SAG A BIT FARTHER SOUTH THROUGH TONIGHT. UPSTREAM
SHORTWAVE THAT WE HAD BEEN WATCHING FOR ANOTHER ROUND OF RAIN
FOR OUR SOUTHERN CWA FRIDAY NOW LOOKS TO BE LESS AMPLIFIED AND
MORE SUPPRESSED TO OUR SOUTH, SO HAVE LOWERED POPS CONSIDERABLY
FRIDAY.
FINALLY, OBSERVATIONS AROUND THE REGION SHOW VERY LITTLE
EVIDENCE OF MEANINGFUL NEAR SFC SMOKE. SATELLITE IMAGERY
WEDNESDAY AFTERNOON/EARLY EVENING SHOWED SMOKE FAR LESS DENSE
APPEARING THAN IT HAD BEEN. THE HRRR, WHICH ADMITTEDLY HASN'T
DONE A GREAT JOB WITH ITS HANDLING OF NEAR SFC SMOKE, SHOWS
FAIRLY LOW NEAR SFC SMOKE CONCENTRATIONS TODAY. CAN'T RULE OUT A
SLIGHT SMELL OF SMOKE IN THE AIR TODAY, BUT NOT SEEING ANYTHING
THAT WOULD SUGGEST A SIGNIFICANT ENOUGH AMOUNT OF NEAR SFC
SMOKE TODAY TO LEAD TO MEANINGFUL VSBY RESTRICTIONS.
- IZZI
FRIDAY NIGHT THROUGH WEDNESDAY:
CONSENSUS FORECAST GUIDANCE HAS BECOME INCREASINGLY PHASED WITH
A PAIR OF TROUGHS OVER THE CENTRAL ROCKIES FRIDAY NIGHT, WHICH
HAS WEAKENED A WESTERN GREAT LAKES RIDGE AND HASTENED THE
DEPARTURE OF AN ASSOCIATED SURFACE HIGH EARLY THIS WEEKEND.
WHILE THE BULK OF MID/UPPER-LEVEL FORCING VIA THE STACKED TROUGH
AND RIGHT ENTRANCE OF AN UPPER JET STREAK SHOULD FAVOR THE
HIGHEST RAIN CHANCES ACROSS CENTRAL ILLINOIS, HAVE INCREASED
POPS ACROSS THE FORECAST AREA IN THE AFTERNOON. AN UPPER-LEVEL
LOW OVER THE FAR NORTHERN GREAT LAKES WILL THEN PUSH A COLD
FRONT WITH THE POTENTIAL FOR SHOWERS AND SOME STORMS ACROSS THE
AREA SUNDAY AFTERNOON AND EVENING. WILL NEED TO MONITOR FOR A
LOW-END SEVERE STORM RISK WITH GUSTY WINDS AS DECENT EFFECTIVE
SHEAR COUNTERACTS MARGINAL MID-LEVEL LAPSE RATES.
THE UPPER-LEVEL LOW WILL SETTLE OVER THE FAR NORTHERN GREAT
LAKES REGION EARLY NEXT WEEK. A SERIES OF EMBEDDED COMPACT WAVES
ROTATING AROUND THE LOW COULD BRING DIURNALLY-ENHANCED SHOWERS
MONDAY AFTERNOON AND POSSIBLY TUESDAY AFTERNOON, CONDITIONAL ON
COINCIDENT TIMING OF THE WAVES WITH PEAK HEATING. A
DEAMPLIFYING MID-LEVEL RIDGE IS THEN PROGGED TO CROSS THE REGION
MIDWEEK, SUPPORTING DRIER AND MORE SEASONABLE CONDITIONS.
KLUBER
AVIATION /06Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 1254 AM CDT THU JUN 5 2025
N/NNE WINDS AROUND 5 KNOTS AT TAF ISSUANCE WILL SETTLE NE 10-15
KNOTS TODAY AND UNDER 10 KNOTS TONIGHT.
GRADUAL CLEARING COMBINED WITH LIGHT WINDS AND RAINFALL OVER
THE PAST 24 HOURS WILL PROMOTE LOWER-END VFR TO MVFR BR THROUGH
SUNRISE. SOME RESIDUAL WILDFIRE SMOKE TRAPPED UNDER THE
NOCTURNAL INVERSION MAY ALSO BE CONTRIBUTING TO THE REDUCED
VISIBILITY. VALUES SHOULD IMPROVE TO VFR LEVELS BY MID-MORNING
AS BR ERODES AND HIGHER SMOKE CONCENTRATIONS REMAIN FAVORED TO
THE WEST OF THE CHICAGO TERMINALS.
WHILE CEILINGS ARE EXPECTED TO REMAIN VFR (EXCEPT AT GYY)
THROUGH THE PERIOD, WILL NEED TO MONITOR FOR THE DEVELOPMENT OF
IFR OR LOWER-END MVFR STRATUS OVER WESTERN LOWER MICHIGAN EARLY
THIS MORNING. UPSTREAM TRAJECTORIES WOULD ADVECT/SPREAD THIS
STRATUS ACROSS SOUTHERN LAKE MICHIGAN AND TOWARD THE CHICAGO
TERMINALS DURING THE MORNING HOURS. HAVE MAINTAINED THE
INCLUSION OF SCT010 FOR MUCH OF THE MORNING AT ORD/MDW AS ANY
INCOMING STRATUS DECK OVER LAKE MICHIGAN SHOULD QUICKLY SCATTER
WITH DAYTIME HEATING/MIXING.
KLUBER
LOT WATCHES/WARNINGS/ADVISORIES
IL...AIR QUALITY ALERT UNTIL MIDNIGHT CDT TONIGHT FOR ILZ005-ILZ006-
ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-
ILZ107-ILZ108.
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR ILZ019-
ILZ020-ILZ021-ILZ106-ILZ107.
IN...AIR QUALITY ALERT UNTIL MIDNIGHT CDT TONIGHT FOR INZ001-INZ002-
INZ010-INZ011.
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR THE IL AND
IN NEARSHORE WATERS.
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