241
FXUS63 KILX 202312
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
612 PM CDT MON APR 20 2026
KEY MESSAGES
- WINDY AND MUCH WARMER CONDITIONS ARE ON TAP FOR TUESDAY. THERE
IS A 40-80% CHANCE OF SOUTHWESTERLY WIND GUSTS EXCEEDING
30MPH, WHICH WILL PUSH AFTERNOON HIGH TEMPERATURES INTO THE
MIDDLE TO UPPER 70S.
- A STORM SYSTEM WILL SPREAD WIDESPREAD SHOWERS AND
THUNDERSTORMS INTO CENTRAL ILLINOIS THURSDAY NIGHT INTO
FRIDAY. AT THIS TIME, IT APPEARS THE RISK FOR SEVERE WEATHER
WILL REMAIN LOW (LESS THAN A 15% CHANCE).
DISCUSSION
ISSUED AT 241 PM CDT MON APR 20 2026
*** WINDY AND WARMER ON TUESDAY ***
A SPRAWLING RIDGE OF HIGH PRESSURE EXTENDING FROM HUDSON BAY TO
THE GULF COAST WILL SHIFT EASTWARD OVER THE NEXT 24 HOURS,
ALLOWING A WARM/SOUTHERLY RETURN FLOW TO DEVELOP ACROSS THE
MIDWEST. MODELS CONTINUE TO SHOW A 40-50KT LOW-LEVEL JET
DEVELOPING WITHIN THE WAA REGIME FROM CENTRAL/NORTHERN MISSOURI
INTO THE SOUTHERN GREAT LAKES TONIGHT INTO TUESDAY MORNING. AS
DIURNAL MIXING COMMENCES, SOME OF THIS HIGHER MOMENTUM AIR WILL
BE DRAWN DOWN TO THE SURFACE BY AROUND 14Z/9AM AS PER THE LATEST
HRRR/RAP. THE 12Z HREF SHOWS A 40-80% CHANCE OF GUSTS OVER 30MPH
ALONG/NORTH OF A LITCHFIELD TO DANVILLE LINE...WITH A 20-30%
CHANCE OF GUSTS OVER 35MPH FOR A COUPLE HOURS PRIOR TO MIDDAY.
THE STRONG SOUTHWESTERLY WINDS IN CONJUNCTION WITH PARTLY TO
MOSTLY SUNNY SKIES WILL HELP PUSH AFTERNOON HIGHS WELL INTO THE
70S.
*** SHOWERS AND A FEW THUNDERSTORMS TUESDAY NIGHT ***
A WEAK COLD FRONT IS PROGGED TO DROP SOUTHWARD INTO THE REGION
TUESDAY NIGHT. THE SOUTHWARD MOMENTUM OF THE BOUNDARY WILL BE
GREATEST ACROSS OHIO/INDIANA, WITH THE TRAILING FRONT ONLY
SLOWLY SINKING SOUTHWARD FURTHER WEST ACROSS ILLINOIS. AS A
RESULT OF THE STRONGEST FRONTAL FORCING, MOST MODELS SUGGEST THE
GREATEST AREAL COVERAGE OF CONVECTION WILL BE FURTHER E/NE
ACROSS CENTRAL/NORTHERN INDIANA. GIVEN CURRENT SET-UP, HAVE
CARRIED 30 POPS ALONG/WEST OF THE ILLINOIS RIVER...INCREASING TO
50 POPS ALONG/NORTHEAST OF A BLOOMINGTON TO CHAMPAIGN LINE.
MOISTURE-POOLING AHEAD OF THE FRONT WILL BE LIMITED, WITH
SURFACE DEWPOINTS ONLY REACHING THE MIDDLE TO UPPER 50S AND
RESULTING SBCAPES GENERALLY LESS THAN 1500J/KG. WHILE THIS IS
SUFFICIENT FUEL FOR THUNDER, WEAK 0-6KM BULK SHEAR OF 30KT OR
LESS WILL PREVENT ORGANIZED STORM DEVELOPMENT.
*** HIGHER RISK FOR THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY ***
AFTER A PERIOD OF WARM/DRY WEATHER WEDNESDAY AND THURSDAY, THE
NEXT SIGNIFICANT STORM SYSTEM WILL PUSH INTO THE REGION BY THE
END OF THE WEEK. WHILE MINOR TIMING DISCREPANCIES EXIST, BOTH
THE 12Z GFS AND ECMWF SUGGEST THE ASSOCIATED COLD FRONT WILL
SWING THROUGH CENTRAL ILLINOIS AROUND MIDDAY FRIDAY. FAVORABLE
INSTABILITY/SHEAR PARAMETERS WILL BE IN PLACE AHEAD OF THE
SYSTEM ACROSS THE PLAINS LATE THURSDAY, RESULTING IN A 15-30%
CHANCE FOR SEVERE WEATHER ALONG/WEST OF A DES MOINES, IOWA TO
TULSA, OKLAHOMA LINE. SOME OF THIS ACTIVITY WILL SPILL EASTWARD
INTO CENTRAL ILLINOIS IN A WEAKENING STATE THURSDAY NIGHT INTO
FRIDAY MORNING. DIURNAL DE-STABILIZATION WILL BE GREATEST FROM
THE OZARKS SOUTHWARD INTO THE LOWER MISSISSIPPI RIVER VALLEY BY
FRIDAY AFTERNOON/EVENING. SO WHILE THE LOCAL SEVERE WEATHER RISK
IS NON-ZERO ON FRIDAY, THE HIGHEST PROBABILITIES (15-30% CHANCE)
WILL BE FOCUSED FROM SOUTHERN MISSOURI SOUTHWARD TO
LOUISIANA/EAST TEXAS.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 612 PM CDT MON APR 20 2026
A LOW LEVEL JET IS EXPECTED TO RAMP UP WEST OF THE MISSISSIPPI
RIVER THIS EVENING, SHIFTING INTO CENTRAL ILLINOIS IN THE 06-08Z
TIME FRAME. HOWEVER, CONDITIONS WOULD BE MORE BORDERLINE ACROSS
EASTERN ILLINOIS. ONCE THE JET BEGINS TO MIX TO THE SURFACE
TUESDAY MORNING, EXPECT SOUTH/SOUTHWEST WINDS TO GUST FROM
25-30 KNOTS THROUGH THE AFTERNOON. AS A WEAK COLD FRONT DROPS
SOUTH INTO THE AREA, SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP TOWARD THE END OF THE PERIOD. RIGHT NOW,
WILL ONLY INCLUDE A PROB30 AT KPIA, WITH STORM ARRIVAL AT KBMI
LOOKING TO BE AFTER 00Z.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...GEELHART
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