196
FXUS63 KILX 121759
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1259 PM CDT SUN APR 12 2026
KEY MESSAGES
- A STRETCH OF WARM WEATHER IS EXPECTED TO BEGIN TODAY AND LAST
THROUGH FRIDAY, WITH DAILY TEMPERATURES CLIMBING NEAR 80
DEGREES. GUSTY WINDS, OCCASIONALLY REACHING 30-40 MPH, WILL
ACCOMPANY THIS WARM PERIOD. BLOWING DUST MAY REDUCE VISIBILITY
WHEREVER EARLY FIELD WORK IS TAKING PLACE ACROSS THE REGION.
- THIS WEEK WILL BE RIDDLED WITH THUNDERSTORM POTENTIAL.
TUESDAY AND WEDNESDAY CURRENTLY EXHIBIT THE HIGHEST
PROBABILITY (15-30%) OF SEVERE WEATHER.
- THERE IS ALSO A POTENTIAL FOR SUBSTANTIAL ACCUMULATIVE
RAINFALL THROUGHOUT THE WEEK, WITH OUR MULTI-MODEL ENSEMBLE
PREDICTING A MEDIUM (40-60%) CHANCE OF EXCEEDING 2 INCHES
THROUGH SATURDAY.
DISCUSSION
ISSUED AT 133 AM CDT SUN APR 12 2026
A SIGNIFICANT WARMING TREND BEGINS TODAY, BRINGING HIGH
TEMPERATURES NEAR 80 DEGREES DAILY THROUGH FRIDAY. THIS SHIFT IS
DUE TO A WARM FRONT LIFTING NORTHWARD ACROSS THE REGION,
SUPPORTED BY STRONG LOW-LEVEL WARM AIR ADVECTION AHEAD OF AN
ACTIVE UPPER-LEVEL LOW MOVING INLAND FROM THE WEST COAST. GUSTY
NON-THUNDERSTORM WIND GUSTS WILL OCCASIONALLY EXCEED 35 MPH
THROUGHOUT TODAY, ACCORDING TO THE LATEST NBM GUIDANCE (01Z).
BLOWING DUST COULD BECOME A VISIBILITY CONCERN WHEREVER EARLY
FIELD WORK IS TAKING PLACE ACROSS THE REGION.
RAIN IS LIKELY (60-80% CHANCE) THIS EVENING, DRIVEN BY SUBTLE
SHORTWAVE ENERGY WITHIN THE BROAD SOUTHWEST MID-LEVEL FLOW, A
LOW-LEVEL JET, AND ISENTROPIC ASCENT. WHILE RAINFALL AMOUNTS ARE
EXPECTED TO RANGE BETWEEN A TRACE TO 0.25 INCHES AREAWIDE,
LOCATIONS NEAR AND NORTH OF THE ILLINOIS RIVER, CLOSER TO THE
AXIS OF THE LOW-LEVEL JET, COULD SEE HIGHER TOTALS RANGING FROM
0.25 TO 0.75 INCHES, ACCORDING TO THE LATEST HREF QPF LPMM
GUIDANCE (00Z).
MONDAY IS EXPECTED TO BE RELATIVELY DRY. THIS IS DUE TO
SYNOPTIC SCALE SUBSIDENCE FOLLOWING THE DEPARTING MID-LEVEL
SHORTWAVE AND ITS ASSOCIATED SHOWERS, AND AS HEIGHT TENDENCIES
SEE A SLIGHT INCREASE.
TUESDAY'S SETUP REMAINS CONDITIONAL FOR WIDESPREAD, POTENTIALLY
SEVERE, CONVECTION, DRIVEN BY MODERATE INSTABILITY FROM SURFACE
TEMPERATURES NEAR 85 F, DEWPOINTS IN THE 60S, AND FAVORABLE
MID- LEVEL LAPSE RATES, ALL COINCIDING WITH AN INTENSIFYING MID-
LEVEL JET.
HOWEVER, THE SYNOPTIC FORCING APPEARS SOMEWHAT NEBULOUS. THE
SURFACE FRONT REMAINS NORTH OF OUR FORECAST AREA, AND THERE IS
NO STRONG SHORTWAVE LIFTING ACROSS THE REGION. MESOSCALE
SOUNDINGS SHOW A "LOADED GUN" PROFILE, BUT THE TRIGGER
MECHANISM FOR STORM INITIATION REMAINS UNCLEAR INTO THE
AFTERNOON HOURS.
CONSEQUENTLY, SIGNIFICANT UNCERTAINTY EXISTS REGARDING THE
TIMING AND LOCATION OF STORM DEVELOPMENT, AND CAMS MAY STRUGGLE
TO ACCURATELY DEPICT THE INITIATION AND EVOLUTION OF STORMS ON
TUESDAY.
AT THIS POINT, GLOBAL MODELS ARE DEPICTING AN INCREASED
LIKELIHOOD OF WIDESPREAD CONVECTIVE ACTIVITY TUESDAY NIGHT,
ASSOCIATED WITH A SHORTWAVE EJECTING AHEAD OF THE MAIN, MORE
VIGOROUS TROUGH TRACKING ACROSS THE LEE OF THE ROCKIES. ALTHOUGH
THE PRECISE TRACK OF THIS LEADING WAVE (WHETHER ACROSS
IOWA/WISCONSIN OR ILLINOIS) REMAINS UNCERTAIN, THE FAVORABLE
CAPE AND SHEAR ENVIRONMENT SHOULD SUPPORT ELEVATED SUPERCELLS
AND MULTICELL CLUSTERS. THE POTENTIAL HAZARDS INCLUDE LARGE
HAIL, OCCASIONAL DOWNBURST WINDS, AND LOCALIZED HEAVY RAIN.
THE OUTLOOK FOR WEDNESDAY HINGES ON THE POTENTIAL PERSISTENCE
OF CONVECTIVE DEBRIS FROM THE PRECEDING NIGHT, WITH MODELS
DIVERGING ON ITS LOCATION. THE GFS SUGGESTS THIS DEBRIS MAY
LINGER OVER OUR AREA INTO WEDNESDAY MORNING, PRECEDING THE MAIN
UPPER TROUGH, WHILE THE ECMWF PLACES IT MUCH FURTHER NORTH,
NEARER TO THE SURFACE FRONT. ESSENTIALLY, IF WE ARE CLEARED OUT
TO START WEDNESDAY MORNING, THERE IS A RISK OF SEVERE WEATHER
AND LOCALIZED FLASH FLOODING BY AFTERNOON. CONVERSELY, IF
CONVECTIVE DEBRIS ENSHROUDS THE AREA, THESE RISKS WILL BE
SIGNIFICANTLY REDUCED. REGARDLESS OF THE WEDNESDAY OUTCOME,
THURSDAY APPEARS TO OFFER A REGIONWIDE BREAK, WITH SYNOPTIC-
SCALE SUBSIDENCE MOVING IN BEHIND THE DEPARTING UPPER TROUGH.
THUNDERSTORM ACTIVITY RETURNS BY THE WEEKEND. THE KEY CONCERNS
STEM FROM PERSISTENT TROUGHING OVER THE WESTERN UNITED STATES
AND A CONTINUOUS NORTHWARD FLOW OF GULF MOISTURE UP THE
MISSISSIPPI VALLEY, PARTICULARLY BY FRIDAY NIGHT AND SATURDAY.
SUCH A PATTERN SUGGESTS THAT OUR AREA WILL CONTINUE TO
EXPERIENCE PERIODS OF CONVECTION. WE WILL NEED TO BE VIGILANT OF
NOT ONLY SEVERE WEATHER DURING THIS TIMEFRAME, BUT ALSO OF
FLOODING AS SUCCESSIVE CONVECTIVE EVENTS COMPOUND.
TEMPERATURES THEN COOL SIGNIFICANTLY BY SUNDAY AS A COLD FRONT
SWEEPS THROUGH THE REGION, FLUSHING OUT THE RESIDENT WARM AND
MOIST AIR MASS FROM THE WEEK PRIOR. CURRENT NBM DETERMINISTIC
GUIDANCE SUPPORTS AFTERNOON HIGHS NEAR 60 DEGREES SUNDAY
AFTERNOON, WITH OVERNIGHT LOWS NEAR 40.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1255 PM CDT SUN APR 12 2026
BROKEN TO OVERCAST MID LEVEL CLOUDS FROM 6-10K FT BLANKETED
CENTRAL IL EARLY THIS AFTERNOON. A SHORT WAVE OVER EASTERN
KANSAS, TO LIFT NORTHEAST INTO CENTRAL/NORTHERN IL BY MID
EVENING, AND SPREAD SHOWERS AND ISOLATED THUNDERSTORMS NE THRU
CENTRAL IL DURING MID/LATE AFTERNOON. THE SHOWERS TO DIMINISH
FROM THE WEST DURING LATE EVENING FROM 03-05Z. CONTINUED TO
MENTION PROB30 GROUP FOR SHOWERS FOR A 4-6 HOUR PERIOD. MVFRF
CEILINGS AND VSBYS WILL BE POSSIBLE WITH LOCALIZED HEAVIER RAIN
SHOWERS THIS EVENING. THERE IS THEN A MEDIUM (50-70%) CHANCE
THAT BROKEN MVFR CEILINGS TRAIL THE MAIN PUSH OF SHOWERS LATER
TONIGHT INTO MONDAY MORNING, ESPECIALLY AT PIA AND BMI.
GENERALLY DRY CONDITIONS ARE EXPECTED OVER CENTRAL IL DURING
OVERNIGHT INTO MIDDAY MONDAY. SSW TO SW WINDS AT 18-25 KTS AND
GUSTS 28-35 KTS THIS AFTERNOON, TO DIMINISH A BIT DURING THIS
EVENING, BUT STILL GUSTING 25-30 KTS. EXPECT SW WINDS 10-15 KTS
WITH GUSTS 20-25 KTS OVERNIGHT INTO MIDDAY MONDAY.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...MJA
DISCUSSION...MJA
AVIATION...07
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