565
FXUS63 KILX 041715
AFDILX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LINCOLN IL
1115 AM CST WED MAR 4 2026
KEY MESSAGES
- THERE IS A MARGINAL RISK (5-15% CHANCE) FOR SEVERE WEATHER ALONG
AND SOUTH OF I-70 FROM 2PM TO 8PM TODAY. THE PRIMARY HAZARDS
WILL BE STRONG WIND GUSTS AND LARGE HAIL...ALTHOUGH AN ISOLATED
TORNADO CANNOT BE RULED OUT.
- AFTER A WINDY AND VERY WARM DAY WITH HIGHS SOARING INTO THE
MIDDLE TO UPPER 70S, THERE IS A SLIGHT RISK (15-30% CHANCE) FOR
SEVERE WEATHER WEST OF THE I-57 CORRIDOR FRIDAY NIGHT AS A COLD
FRONT APPROACHES FROM THE WEST.
UPDATE
ISSUED AT 1110 AM CST WED MAR 4 2026
UPDATED THE FORECAST TO INCREASE FOG COVERAGE LONGER TODAY OVER
CENTRAL IL WITH AREAS OF DENSE FOG NORTH OF I-70 AND NW TO THE IL
RIVER. ISSUED A SPECIAL WEATHER STATEMENT FOR THE AREAS OF DENSE
FOG AND A DENSE FOG ADVISORY WAS ISSUED UNTIL 18Z/NOON FOR CENTRAL
AND WEST CENTRAL INDIANA. LATEST CAMS SHOW THE FOG GRADUALLY
LIFTING BUT NOT COMPLETELY GOING AWAY OVER CENTRAL IL WITH THE LOW
STRATUS DECK REMAINING. FOG TO ONCE AGAIN TO BECOME MORE
WIDESPREAD AND DENSER DURING TONIGHT OVER PORTIONS OF CENTRAL IL
AND LINGER INTO THU MORNING.
OTHERWISE REST OF FORECAST LOOKS GOOD INTO TONIGHT. SPC DAY1
OUTLOOK HAS EXPANDED THE MARGINAL RISK OF SEVERE STORMS A BUT
FURTHER NORTH TO SHELBYVILLE TO PARIS (WHERE WARM FRONT LIFTS
SLOWLY UP TO THIS AFTERNOON) FOR MAINLY LARGE HAIL RISK. THERE IS
A SLIGHT RISK OF SEVERE STORMS SOUTH OF HIGHWAY 50 OVER SOUTHERN
REACHES OF CLAY, RICHLAND AND LAWRENCE COUNTIES FROM MID AFTERNOON
INTO EARLY EVENING WHERE TORNADO THREAT ALSO POSSIBLE WITH THE
LARGE HAIL.
07
DISCUSSION
ISSUED AT 339 AM CST WED MAR 4 2026
..WEATHER SYNOPSIS
08Z/2AM SURFACE ANALYSIS SHOWS A 1025MB HIGH OVER SOUTHERN LAKE
MICHIGAN...WHILE A STATIONARY FRONTAL BOUNDARY EXTENDS FROM
SOUTHERN OHIO TO OKLAHOMA. ALOFT...THE SHORT-WAVE TROUGH THAT
INTERACTED WITH THE BOUNDARY TO BRING WIDESPREAD SHOWERS AND
THUNDERSTORMS TO CENTRAL ILLINOIS LAST EVENING IS PUSHING INTO
INDIANA. MEANWHILE A STRONGER WAVE IS NOTED ON UPSTREAM WATER
VAPOR IMAGERY OVER EASTERN COLORADO.
..SEVERE WEATHER RISK THIS AFTERNOON/EVENING
AS THE COLORADO SHORT-WAVE APPROACHES, A WEAK WAVE OF LOW PRESSURE
IS EXPECTED TO FORM ALONG THE FRONT...CAUSING IT TO LIFT SLOWLY
NORTHWARD TO NEAR I-70 LATER TODAY. THERE WILL BE A PRONOUNCED N/S
TEMPERATURE GRADIENT ACROSS THE BOUNDARY AS TEMPERATURES HOVER IN
THE UPPER 40S AND LOWER 50S IN THE OVERCAST AIRMASS TO THE NORTH
ACROSS THE MAJORITY OF CENTRAL ILLINOIS AND CLIMB INTO THE LOWER
TO MIDDLE 60S ALONG AND SOUTH OF I-70. WITH SURFACE DEWPOINTS
INCREASING TO THE UPPER 50S TO AROUND 60 ACROSS THIS AREA, THE
ATMOSPHERE IS EXPECTED TO BECOME MODESTLY UNSTABLE. THE 00Z HREF
INDICATES MEAN MUCAPE VALUES PEAKING IN THE 600-800J/KG RANGE. AS
A 500MB JET STREAK STRENGTHENS FROM THE SOUTHERN PLAINS INTO THE
OHIO RIVER VALLEY, 0-6KM BULK SHEAR WILL REACH 45-55KT. IN ADDITION,
THE HREF IS SHOWING 0-1KM STORM RELATIVE HELICITY (SRH) OF 100-150
IN THE VICINITY OF THE BOUNDARY DURING PEAK INSTABILITY. THESE
PARAMETERS ALL SUPPORT THE RISK FOR STRONG TO POTENTIALLY SEVERE
CONVECTION. CAMS VARY ON THE TIMING OF CONVECTIVE INITIATION:
HOWEVER, A SLIGHTLY SLOWER TREND THAN PREVIOUSLY THOUGHT IS
BECOMING CLEAR. A NAM/HRRR/ARW/NSSL HRW CONSENSUS POINTS TO STORMS
FIRING SOUTH OF THE FRONT ACROSS SOUTHERN MISSOURI LATE THIS
MORNING...WITH CELLS TRACKING E/NE ACROSS THE SE KILX CWA BETWEEN
2PM AND 8PM. THE PRIMARY HAZARDS WITH THE STORMS ALONG/SOUTH OF
I-70 TODAY WILL BE SCATTERED DAMAGING WIND GUSTS IN EXCESS OF
60MPH AND HAIL LARGER THAN QUARTERS: HOWEVER, AN ISOLATED TORNADO
CANNOT BE RULED OUT AS PER THE HREF SIGNIFICANT TORNADO PARAMETER
(STP) INCREASING TO 0.5-1 BETWEEN HIGHWAY 50 AND THE OHIO RIVER.
FURTHER NORTH ACROSS THE REMAINDER OF CENTRAL ILLINOIS, STORM
COVERAGE WILL BE CONSIDERABLY LESS AND SEVERE WEATHER IS NOT
ANTICIPATED.
..SEVERE WEATHER RISK FRIDAY NIGHT
AFTER A FEW LINGERING SHOWERS MAINLY THURSDAY MORNING, A PERIOD OF
MOSTLY DRY WEATHER IS EXPECTED THURSDAY AFTERNOON AND EVENING
BEFORE ANOTHER PROMINENT SHORT-WAVE TROUGH CURRENTLY OFF THE COAST
OF THE PACIFIC NORTHWEST APPROACHES. AS THE DEEP-LAYER FLOW
PATTERN BECOMES MORE SOUTHWESTERLY AHEAD OF THE WAVE, THE
PERSISTENT FRONTAL BOUNDARY DRAPED ALONG THE I-70 CORRIDOR WILL
SURGE NORTHWARD LATE THURSDAY NIGHT INTO FRIDAY MORNING, TRIGGERING
A FEW SHOWERS AND THUNDERSTORMS. WHILE WIDESPREAD SEVERE WEATHER
IS NOT ANTICIPATED WITH FROPA, WILL NEED TO MONITOR THE POTENTIAL
FOR SOME HAIL WITH THE STRONGER CELLS. ANY MORNING CONVECTION WILL
QUICKLY LIFT INTO WISCONSIN/MICHIGAN BY MIDDAY...FOLLOWED BY A
WINDY AND VERY WARM AFTERNOON WITH HIGHS SOARING INTO THE MIDDLE
TO UPPER 70S. DESPITE THE WARMER/MORE HUMID AIRMASS FLOWING INTO
THE REGION, A LACK OF FORCING AND THE PRESENCE OF MID-LEVEL
CAPPING WILL PREVENT ANY STORM DEVELOPMENT DURING THE DAY.
MEANWHILE FURTHER UPSTREAM, LOW PRESSURE ASSOCIATED WITH THE
SHORT-WAVE TROUGH WILL TRACK FROM WESTERN KANSAS FRIDAY MORNING TO
LAKE SUPERIOR BY SATURDAY MORNING. GIVEN THE VERY UNSTABLE/SHEARED
ENVIRONMENT AHEAD OF THE LOW AND ITS ASSOCIATED COLD FRONT, A
BROKEN LINE OF STRONG TO SEVERE CONVECTION IS EXPECTED TO DEVELOP
FROM IOWA TO CENTRAL TEXAS BY LATE AFTERNOON. THESE CELLS WILL
TRACK NORTHEASTWARD AND WILL EVENTUALLY SPILL INTO THE ILLINOIS
RIVER VALLEY LATE FRIDAY EVENING. DESPITE DAYTIME INSTABILITY
WANING AFTER DARK, A POWERFUL 55-65KT 850MB JET STREAK WILL
DEVELOP AHEAD OF THE FRONT FROM TEXAS TO THE GREAT LAKES. THIS
WILL ADD PLENTY OF WIND ENERGY TO THE ATMOSPHERIC PROFILE AND WILL
SUBSTANTIALLY INCREASE THE CHANCE OF DAMAGING WIND GUSTS BEING
MIXED TO THE SURFACE ONCE THE CONVECTION ARRIVES. AS A RESULT, SPC
IS HIGHLIGHTING ALL LOCATIONS WEST OF THE I-57 CORRIDOR WITH A
SLIGHT RISK (15-30% CHANCE) FOR SEVERE WEATHER. CURRENT
PROJECTIONS SUGGEST THIS WILL BE A NOCTURNAL WIND EVENT FROM LATE
EVENING INTO THE OVERNIGHT HOURS. THE EXACT EASTWARD EXTENT OF THE
RISK AREA REMAINS IN QUESTION AND WILL BE FINE-TUNED OVER THE
NEXT FEW FORECAST CYCLES AS DETAILS BECOME CLEARER.
BARNES
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 542 AM CST WED MAR 4 2026
IFR CEILINGS/VISBYS ARE PRESENT AT ALL CENTRAL ILLINOIS TERMINALS
EXCEPT KPIA EARLY THIS MORNING. A NE WIND OF AROUND 10KT HAS
HELPED DRIER AIR FROM NORTHERN ILLINOIS CAUSE A HIGHER CEILING AT
KPIA:HOWEVER, NAM/HRRR GUIDANCE SUGGESTS CLOUD BASES WILL
GRADUALLY LOWER TO IFR AT KPIA BY AROUND 18Z. A FEW SHOWERS WILL
SKIRT ALONG/SOUTH OF I-72 THROUGH 14Z/8PM...FOLLOWED BY A PERIOD
OF MOSTLY DRY WEATHER BEFORE A WAVE OF SHOWERS/STORMS APPROACHES
FROM THE SOUTHWEST THIS AFTERNOON. THIS CONVECTION WILL LARGELY
REMAIN FURTHER SOUTH ALONG THE I-70 CORRIDOR: HOWEVER, IT MAY
TRACK FAR ENOUGH NORTH TO WARRANT THUNDER MENTION AT KSPI/KDEC/KCMI
BETWEEN 19Z AND 23Z. AFTER THAT, ANOTHER LULL IN PRECIP WILL BE
OBSERVED BEFORE A RENEWED ROUND OF SHOWERS/THUNDER ARRIVES OVERNIGHT.
CONFIDENCE REMAINS LOW CONCERNING THE TIMING AND TRACK OF THE
OVERNIGHT STORMS, SO HAVE CARRIED A PROB30 GROUP FOR THUNDER AT
THE I-72 TERMINALS AND JUST MENTIONED SHOWERS AT KPIA/KBMI.
ANOTHER AVIATION FORECAST CHALLENGE WILL BE VISIBILITIES. WITH
CENTRAL ILLINOIS REMAINING NORTH OF A STATIONARY FRONTAL BOUNDARY
TODAY/TONIGHT, FOG WILL BE PERSISTENT. CAMS SUGGEST VISBY
REDUCTIONS THROUGHOUT THE DAY...WITH FOG POTENTIALLY BECOMING
DENSE BY TONIGHT. AT THIS POINT, HAVE LOWERED VISBYS TO AROUND 1/2
MILE AT ALL SITES AFTER THE 03Z-05Z TIME FRAME.
BARNES
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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