395
FXUS63 KILX 081746
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1246 PM CDT SUN MAR 8 2026
KEY MESSAGES
- TEMPERATURES TREND WARMER, IN THE LOW TO MID 60S TODAY BUT
REACHING NEAR RECORD LEVELS BY TUESDAY WHEN HIGHS APPROACH 80
DEGREES. BREEZY SOUTHWEST WINDS COULD GUST TO 30 MPH TODAY, THEN
35 MPH ON MONDAY.
- SEVERE STORMS COULD DEVELOP TUESDAY AFTERNOON INTO TUESDAY
NIGHT, WITH ALL SEVERE HAZARDS POSSIBLE. THERE IS AN ENHANCED
RISK (LEVEL 3 OF 5) OF SEVERE STORMS NORTH OF A SPRINGFIELD TO
RANTOUL LINE, WITH A SLIGHT RISK (LEVEL 2 OF 5) TO THE SOUTH.
- BENEFICIAL RAINFALL IS LIKELY WITH THE TUESDAY-WEDNESDAY SYSTEM.
THERE IS A 60-80% CHANCE OF AT LEAST 1" OF RAIN. THUNDERSTORMS
COULD LEAD TO LOCALIZED HEAVY AMOUNTS (10% CHANCE OF OVER 3" OF
RAIN).
DISCUSSION
ISSUED AT 305 AM CDT SUN MAR 8 2026
*** TODAY INTO TUESDAY ***
EARLY SUN AM, THE UPPER LEVELS FEATURED A CUTOFF LOW NEAR BAJA
CALIFORNIA AND BROAD TROUGHING OVER THE EASTERN US WITH EMBEDDED
DISTURBANCES TRACKING WELL TO THE NORTH. A COLD FRONT EXTENDING
FROM NEW ENGLAND TO TEXAS WILL SLOWLY SAG SOUTH TODAY. CLOSER TO
HOME, A WEAK SFC RIDGE AXIS THAT EXTENDS FROM OK INTO IL IS
SHIFTING SOUTH, WHICH WILL SWING WINDS AROUND TO SOUTHERLY. AS
ANTICIPATED IN PREVIOUS FORECASTS, CONTINUED CLOUD COVER ACROSS
EASTERN IL IS KEEPING TEMPS WARMER, WITH READINGS STILL IN THE 40S
EAST OF I-57 AS OF 12AM CST/06Z COMPARED TO MID-30S WEST OF I-55.
BETWEEN A SERIES OF LOW PRESSURE TRACKING ACROSS CANADA/THE
NORTHERN GREAT LAKES AND THE SFC RIDGE AXIS SHIFTING SOUTH,
EXPECT PERSISTENT SOUTHWEST FLOW ACROSS IL INTO TUES. THIS WILL
RESULT IN A WARMING TREND THROUGH TUES, WITH HIGHS IN THE 60S
TODAY, 70S ON MON, AND THEN APPROACHING 80F ON TUES. THE RECORD
HIGHS FOR MAR 10TH ARE 78F AT LINCOLN (50% CHANCE OF TYING THE
RECORD), 80F AT SPRINGFIELD (40% CHANCE), AND 77F AT PEORIA (65%
CHANCE). RECORD HIGHS ARE CERTAINLY POSSIBLE ON TUESDAY.
MINIMAL WEATHER IMPACTS ARE EXPECTED UNTIL THE CUTOFF LOW EJECTS
AND BRINGS STORM CHANCES INTO TUES NIGHT, ALTHOUGH I CONTINUE TO
HAVE MINOR CONCERN THAT GUIDANCE IS TOO HIGH WITH THE FORECAST
DEWPOINTS TODAY WHICH HAS IMPLICATIONS FOR THE FIRE WX CONDITIONS.
THE FRONT DRAPED TO THE SOUTH WILL LIMIT MOISTURE ADVECTION
TODAY. FORECAST SOUNDINGS SUGGEST A WELL-MIXED PBL, BUT DEPICT A
SHALLOW NEAR-SFC LAYER OF HIGHER DEWPOINTS COMPARED TO THE REST OF
THE PBL. THE EXPECTATION IS THAT EFFICIENT MIXING WILL DRIVE SFC
DEWPOINTS LOWER THAN GUIDANCE SUGGESTS, AND MADE ADJUSTMENTS TO
THE MODEL BLEND ACCORDINGLY. MINIMUM RH VALUES COULD DROP TOWARDS
30%, WHICH COMBINED WITH PEAK GUSTS OF 25-30 MPH COULD LEAD TO
SOME MINOR RISK OF UNWANTED FIRE SPREAD. BREEZIER WINDS ARE
EXPECTED ON MON, WITH FORECAST SOUNDINGS SUGGESTING PEAK GUSTS
AROUND 35 MPH. MOISTURE ADVECTION DOES START TO INCREASE, HOWEVER,
SO RH VALUES SHOULD BE A BIT HIGHER THAN TODAY.
*** TUESDAY STORM THREAT ***
BETWEEN NEAR-RECORD TEMPS, CONTINUED MOISTURE RETURN (DEWPOINTS
INTO THE 60S) , AND INCREASING UPPER LEVEL LIFT IN RESPONSE TO
APPROACHING TROUGHS, THE STAGE WILL BE SET FOR STORMS TUES PM INTO
WED, AND THESE COULD BE SEVERE. THE EMERGING CUTOFF LOW IS JOINED
BY A NORTHERN STREAM WAVE TO PRODUCE BROAD HEIGHT FALLS ALOFT AND
PRESSURE FALLS AT THE SFC, WITH MOST GUIDANCE DEPICTING A WARM
FRONT EXTENDING FROM SOUTH OF OMAHA, NE, TO FAR NORTHERN IL TUES
MORNING. A SFC LOW THEN LIFTS ALONG THIS FRONTAL ZONE, WHICH
COMBINED WITH THE INCREASING ASCENT ALOFT LEADS TO CONVECTIVE
DEVELOPMENT NEAR THE FRONTAL ZONE (AND PERHAPS WITHIN THE WARM
SECTOR).
FORECAST SOUNDINGS SHOW A CLASSIC LOADED GUN LOOK THROUGH THE
MORNING/EARLY AFTERNOON, THAT IS, STRONG CAPPING TO LIMIT
CONVECTIVE DEVELOPMENT DESPITE INCREASING INSTABILITY. AREA-
AVERAGED SOUNDINGS FROM THE GFS/NAM INDICATE SEASONABLY HIGH
SBCAPE VALUES (1000-1500 J/KG), AND SUCH VALUES ARE ALSO SUGGESTED
BY A MAJORITY OF ENSEMBLE MEMBERS. CONVECTIVE INHIBITION (CIN)
RANGES FROM -25 TO -100 J/KG THROUGH MID-AFTERNOON, BUT STARTS TO
ERODE INTO THE LATE AFTERNOON/EVENING. LOW-LEVEL WIND PROFILES
APPEAR QUITE SUPPORTIVE OF SEVERE STORMS, VEERING WITH HEIGHT
(CLOCKWISE TURNING) AND INCREASING IN MAGNITUDE, AT LEAST IN THE
LOWEST KILOMETER. THIS WIND PROFILE RESULTS IN 0-1KM SRH VALUES
OVER 150 J/KG. THIS ENVIRONMENT IS CONDITIONALLY SUPPORTIVE OF ALL
SEVERE HAZARDS, PENDING CAP EROSION AND THE SPECIFIC STORM MODE
THAT DEVELOPS.
GIVEN THE STRONG CAP, STORM DEVELOPMENT MAY BE CONFINED TO THE
FRONTAL ZONE RATHER THAN THE OPEN WARM SECTOR, ALTHOUGH THE STRONG
SYNOPTIC-SCALE ASCENT ADDS UNCERTAINTY TO THE EQUATION. DEEP
LAYER SHEAR VECTORS ORIENTED ROUGHLY PARALLEL TO THE FRONTAL ZONE
SUGGEST A TREND TOWARDS UPSCALE GROWTH. WE ARE STILL BEYOND THE
RANGE OF MOST CAMS, SO DON'T YET HAVE A CHANCE TO SEE HOW THEIR
MODELED EVOLUTION COMPARES TO THE EXPECTATIONS OUTLINED ABOVE.
THERE IS ALSO THE DIURNAL TIMING FACTOR. WITH THE FRONT POSITIONED
JUST TO OUR NORTHWEST, IT MAY NOT BE UNTIL AFTER SUNSET THAT
ROBUST STORMS MOVE INTO THE ILX CWA. INTO TUES NIGHT, LLJ FORCING
INCREASES, WHICH COULD HELP INCREASE CONVECTIVE COVERAGE AND WOULD
FURTHER STRENGTHEN THE WIND SHEAR. THE DEGREE TO WHICH SFC
INSTABILITY WILL PERSIST INTO THE NIGHT IS LOW CONFIDENCE.
IN SUMMARY, A PARAMETER SPACE SUPPORTIVE OF SEVERE STORMS WILL
EXIST ON TUESDAY-TUESDAY NIGHT. THE EXPECTATION IS THAT A STRONG
CAP WILL LIMIT STORM DEVELOPMENT UNTIL LATE AFTERNOON OR EVENING,
WITH AREAS NEAR THE FRONTAL ZONE HAVING THE BEST CHANCE OF STORMS
FORMING DURING THE AFTERNOON/EVENING. THERE IS AN ENHANCED RISK
(LEVEL 3 OF 5) OF SEVERE STORMS NORTH OF A SPRINGFIELD TO RANTOUL
LINE, WITH A SLIGHT RISK (LEVEL 2 OF 5) TO THE SOUTH.
*** WEDNESDAY AND BEYOND ***
THE FRONTAL ZONE PUSHES SOUTHEAST ON WED AS A COLD FRONT, KEEPING
SHOWERS/STORMS IN THE FORECAST UNTIL IT DEPARTS. ENSEMBLE GUIDANCE
CONTINUES TO HIGHLIGHT BENEFICIAL RAINFALL FROM THE TUES-WED
SYSTEM, WITH A 60-80% CHANCE OF TOTAL RAINFALL OF AT LEAST 1", AND
A 20-50% CHANCE OF 2" (HIGHEST SOUTH OF I-72).
BY THURSDAY, HIGHS RETURN TO THE UPPER 40S/LOW 50S, WHICH IS NEAR
SEASONABLE VALUES. A CLIPPER-STYLE SYSTEM TRACKING ACROSS THE
GREAT LAKES REGION THUR NIGHT INTO FRI COULD OFFER A LOW CHANCE
(20%) OF LIGHT RAIN (PERHAPS MIXING WITH SNOW), MAINLY NORTH OF
I-74. THE PRECIP CHANCES ASSOCIATED WITH THIS SYSTEM INCREASE AS
YOU GO NORTHWARD (OVER 40% NORTH OF THE I-88 CORRIDOR IN N IL).
THE PATTERN REMAINS PROGRESSIVE, WITH ANOTHER DISTURBANCE KEEPING
PRECIP CHANCES IN THE FORECAST FOR THE LATTER HALF OF THE WEEKEND
(40-60% CHANCE SAT NIGHT INTO SUN).
ERWIN
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN MAR 8 2026
VFR CONDITIONS ARE FORECAST TO CONTINUE ACROSS THE CENTRAL IL
AIRPORTS THROUGH 18Z/1 PM MONDAY, DUE TO NEARBY HIGH PRESSURE
RIDGE WITH FAIR SKIES (FEW PASSING CIRRUS CLOUDS). WEAK 1019 MB
HIGH PRESSURE OVER AR AND RIDGING INTO THE LOWER OHIO RIVER
VALLEY, WHILE 989 MB LOW PRESSURE WAS NORTH OF THE MT/ND BORDER IN
FAR SOUTHERN SASKATCHEWAN. HIGH PRESSURE TO SETTLE INTO THE
CENTRAL APPALACHIANS OVERNIGHT WHILE LOW PRESSURE TRACKS EASTWARD
JUST NORTH OF THE US BORDER TO NORTH OF LAKE SUPERIOR BY DAWN
MONDAY WHILE PUSHING COLD FRONT INTO NORTHERN IA AND CENTRAL WI
MON MORNING. FAIRLY TIGHT PRESSURE GRADIENT OVER CENTRAL IL THIS
AFTERNOON WITH SW WINDS GUSTING 20-26 KTS AND STILL BE GUSTING IN
LOWER 20 KTS THIS EVENING AFTER SUNSET. ADDED LLWS TO THE AIRPORTS
FROM I-55 NW LATE EVENING/OVERNIGHT STARTING AT PIA BETWEEN
03-04Z, BMI AROUND 05Z AND JUST FOR AT SPI STARTING AT 07Z.
1.5-2KT SW WINDS OF 35-45 KTS BY OVERNIGHT AND DIMINISH BY 12Z/7
AM MON. SSW WINDS DIMINISH TO 9-14 KTS OVERNIGHT AND INCREASE TO
12-16 KTS WITH GUSTS 20-25 KTS AFTER 15Z/10 AM MONDAY.
07
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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