286
FXUS63 KILX 280830
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
330 AM CDT SUN JUN 28 2026
KEY MESSAGES
- A DENSE FOG ADVISORY IS IN EFFECT ALONG AND EAST OF THE I-55
CORRIDOR THROUGH 8AM TODAY.
- A HEAT ADVISORY IS IN EFFECT FOR LOCATIONS ALONG AND SOUTHWEST
OF A PEORIA...TO DECATUR...TO ROBINSON LINE THIS AFTERNOON.
THE ADVISORY EXPANDS TO INCLUDE ALL OF CENTRAL ILLINOIS
MONDAY THROUGH THURSDAY WHEN MAXIMUM HEAT INDEX VALUES EXCEED
105 DEGREES.
DISCUSSION
ISSUED AT 330 AM CDT SUN JUN 28 2026
**** DENSE FOG EARLY THIS MORNING ****
VERY MOIST BOUNDARY LAYER CONDITIONS EXIST ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING AS EVIDENCED BY 07Z/2AM SURFACE
DEWPOINTS IN THE UPPER 60S AND LOWER 70S. WHILE SKIES HAVE
GENERALLY REMAINED OVERCAST, THERE HAVE BEEN ENOUGH BREAKS IN
THE CLOUD COVER TO ALLOW TEMPERATURES TO COOL TO THE DEWPOINT
AND AREAS OF FOG TO DEVELOP. CAMS HAVE A GOOD HANDLE ON THE
SITUATION AND HAVE BEEN CONSISTENTLY FOCUSING THE LOWEST VISBYS
ALONG/EAST OF THE I-55 CORRIDOR. WITH THE PROPER SYNOPTIC
PATTERN IN PLACE, A CLEAR SIGNAL FROM THE MODELS, AND AREA OBS
BEGINNING TO SHOW LOCALLY DENSE FOG, OPTED TO ISSUE A DENSE FOG
ADVISORY FOR THE EASTERN HALF OF THE KILX CWA THROUGH 8AM.
**** A FEW THUNDERSTORMS TODAY ****
07Z/2AM SURFACE ANALYSIS SHOWS A NEARLY STATIONARY FRONTAL
BOUNDARY EXTENDING FROM NORTHERN MISSOURI TO WESTERN KENTUCKY.
SCATTERED CONVECTION HAS FORMED IMMEDIATELY ALONG THE FRONT AND
WILL CONTINUE TO SKIRT THE KILX CWA TO THE S/SW THROUGH SUNRISE.
AS UPPER HEIGHTS BEGIN TO RISE IN RESPONSE TO A DEEP TROUGH
DIGGING WEST OF THE ROCKIES, THE FRONT WILL GRADUALLY GET NUDGED
NORTHWARD TODAY. AS A RESULT, A FEW SHOWERS/STORMS WILL DEVELOP
AS FAR NORTH AS A GALESBURG...TO DECATUR...TO ROBINSON LINE
LATER THIS MORNING BEFORE DISSIPATING BEFORE MIDDAY. AREAL
COVERAGE WILL REMAIN LOW (20% OR LESS) AND ANY STORMS THAT
OCCUR ARE NOT EXPECTED TO BE SEVERE. MEANWHILE FURTHER
NORTHWEST, A CLUSTER OF STRONG TO SEVERE THUNDERSTORMS AIDED BY
A 55-60KT 850MB JET STREAK OVER EASTERN SOUTH DAKOTA ARE
EXPECTED TO TRACK E/SE ACROSS SOUTHERN MINNESOTA/NORTHERN IOWA
THIS MORNING. WHILE THIS ACTIVITY WILL EVENTUALLY OUTRUN THE
NOCTURNAL JET, AMPLE MOIST INFLOW FROM THE SOUTH MAY HELP
MAINTAIN THE CONVECTION IN A MUCH WEAKENED STATE AS IT CROSSES
INTO SOUTHERN WISCONSIN/NORTHERN ILLINOIS THIS AFTERNOON. MOST
CAMS EITHER SHOW THE CLUSTER COMPLETELY DISSIPATING OR KEEP IT
ENTIRELY NORTH OF THE KILX CWA ALONG/NORTH OF I-80. HOWEVER,
BOTH THE HRRR AND RRFS INDICATE IT MAY DIP A BIT FURTHER
SOUTHEASTWARD TOWARD THE I-74 CORRIDOR. GIVEN CURRENT UPSTREAM
SATELLITE/RADAR TRENDS AND THE CONSISTENT HRRR/RRFS SOLUTION,
HAVE INCLUDED 20-30 POPS ALONG/NORTH OF A MACOMB TO BLOOMINGTON
LINE THIS AFTERNOON. WHILE THE RISK FOR SEVERE WEATHER WILL BE
LOW WITH THE DECAYING CLUSTER, THE LATEST DAY 1 SPC CONVECTIVE
OUTLOOK BRUSHES KNOX/STARK/MARSHALL COUNTIES WITH A MARGINAL
RISK (LEVEL 1 OF 5) FOR SEVERE. IF THE CELLS MANAGE TO DROP THAT
FAR SOUTH, THINK THE PRIMARY RISK WILL BE GUSTY 40-50MPH WINDS.
**** FIRST SUMMER HEATWAVE ****
AS HAS BEEN ADVERTISED FOR THE LAST SEVERAL DAYS, THE FIRST
PROLONGED HEATWAVE OF THE SUMMER IS IMMINENT. AS THE FRONTAL
BOUNDARY SHIFTS NORTHWARD, A HOTTER AIRMASS WILL GRADUALLY
TRICKLE INTO CENTRAL ILLINOIS TODAY. THE MAGNITUDE OF THE HEAT
WILL BE MITIGATED BY CONSIDERABLE CLOUD COVER ACROSS THE BOARD
THIS MORNING AND BY CONVECTIVE DEBRIS ALONG/NORTH OF I-74
THROUGH THE AFTERNOON. AS A RESULT, THINK HIGHS WILL BE HELD IN
THE 80S ACROSS MUCH OF THE CWA...WITH READINGS AT OR SLIGHTLY
ABOVE 90 CONFINED TO THE W/SW. DECIDED TO LEAVE THE CURRENT HEAT
ADVISORY IN PLACE FOR LOCATIONS ALONG/SOUTHWEST OF A
PEORIA...TO DECATUR...TO ROBINSON LINE THIS AFTERNOON, ALTHOUGH
HEAT INDEX VALUES WILL LIKELY REMAIN BELOW ADVISORY CRITERIA OF
105 DEGREES.
ONCE THE FRONT LIFTS INTO THE UPPER MIDWEST/GREAT LAKES AND
UPPER HEIGHTS RISE IN EARNEST, TEMPERATURES WILL CLIMB INTO THE
LOWER TO MIDDLE 90S MONDAY THROUGH THURSDAY. WITH DEWPOINTS IN
THE MIDDLE 70S, HEAT INDEX VALUES WILL PEAK AT OR ABOVE 105
DEGREES EACH AFTERNOON. GIVEN INCREASED CONFIDENCE CONCERNING
THE STRENGTH/POSITION OF THE UPPER RIDGE, HAVE ISSUED A
PROLONGED HEAT ADVISORY FOR MONDAY AFTERNOON THROUGH THURSDAY
EVENING.
MODELS SHOW A SERIES OF SHORT-WAVE TROUGHS GRADUALLY FLATTENING
AND SHIFTING THE RIDGE EASTWARD LATER IN THE WEEK. WITH
INCREASED CLOUD COVER AND RAIN CHANCES, TEMPERATURES AND
CORRESPONDING HEAT INDEX READINGS WILL COOL SLIGHTLY FOR THE
UPCOMING HOLIDAY WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1236 AM CDT SUN JUN 28 2026
A WARM FRONT DRAPED OVER THE AREA WILL LEAD TO LOW STRATUS AND FOG
OVERNIGHT INTO MORNING. HIGH RESOLUTION GUIDANCE SUGGESTS THE LOWEST
CEILINGS/VISBYS WILL BE CONFINED IN EAST-CENTRAL PARTS OF THE STATE,
WHICH IS WHERE TEMPO GROUPS HAVE BEEN ADDED FOR A PERIOD OF 1SM OR
LESS VISBYS ARE FAVORED. CONDITIONS IMPROVE BY MID TO LATE MORNING
WHEN ALL AIRFIELDS ARE EXPECTED TO RETURN TO VFR. WINDS VEER TO THE
SOUTH-SOUTHEAST LATER ON SUNDAY WITH SPEEDS INCREASING. OCCASIONAL
GUSTS AROUND 20 KTS APPEAR LIKELY AT WESTERN TERMINALS (KPIA-
KSPI-KBMI) AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF A
DEEPENING LOW OVER THE PLAINS.
ILX WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS
EVENING FOR ILZ027>029-036-037-040>042-047>054-061-062-066>068-
071>073.
HEAT ADVISORY FROM 11 AM MONDAY TO MIDNIGHT CDT THURSDAY NIGHT
FOR ILZ027>031-036>038-040>057-061>063-066>068-071>073.
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ILZ038-
042>046-052>057-061>063-066>068-071>073.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...NMA
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