267
FXUS63 KILX 291739
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1239 PM CDT SAT MAR 29 2025
KEY MESSAGES
- AN APPROACHING STORM SYSTEM WILL TRIGGER THUNDERSTORMS ACROSS
CENTRAL ILLINOIS SUNDAY AFTERNOON AND EVENING. THERE IS AN
ENHANCED RISK (LEVEL 3 OF 5) FOR SEVERE WEATHER EVERYWHERE EAST
OF THE ILLINOIS RIVER.
- ALL SEVERE WEATHER MODES WILL BE POSSIBLE WITH THE STORMS ON
SUNDAY...INCLUDING DAMAGING WIND GUSTS, LARGE HAIL, AND
TORNADOES.
- MUCH COLDER WEATHER WILL ARRIVE EARLY NEXT WEEK...WITH LOW
TEMPERATURES MONDAY NIGHT DROPPING TO NEAR OR BELOW FREEZING.
SHORT TERM
(TODAY THROUGH SUNDAY)
ISSUED AT 354 AM CDT SAT MAR 29 2025
HIGH PRESSURE ANCHORED OFF THE COAST OF THE CAROLINAS CONTINUES TO
SUPPLY A WARM/SOUTHERLY FLOW ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...WITH 08Z/3AM TEMPERATURES STILL IN THE LOWER TO MIDDLE
60S. DESPITE SOUTH WINDS FROM THE GULF, BOUNDARY LAYER MOISTURE
REMAINS MEAGER AS EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING
SHOWING A PRONOUNCED DRY LAYER BELOW 750MB. AS LOW-LEVEL MOISTURE
SLOWLY INCREASES, A BAND OF SHOWERS IS EXPECTED TO DEVELOP WITHIN
THE BROAD WAA REGIME TODAY. LATEST RADAR IMAGERY IS BEGINNING TO
SHOW THE FIRST SIGNS OF THE SHOWERS ALONG/SOUTH OF I-70: HOWEVER,
ONLY A FEW SITES HAVE REPORTED LIGHT RAIN/SPRINKLES REACHING THE
GROUND THUS FAR. FORECAST SOUNDINGS SHOW GRADUAL TOP-DOWN MOISTENING
OF THE PROFILE THIS MORNING, WHICH WILL EVENTUALLY SUPPORT PRECIP.
MODELS CONTINUE TO FOCUS THE MOST WIDESPREAD SHOWERS ALONG/EAST OF
I-55...WITH LOCATIONS FURTHER WEST SEEING ONLY WIDELY SCATTERED
PRECIP. HAVE THEREFORE CARRIED LIKELY POPS (60-70%) EVERYWHERE
EAST OF I-55...WITH 30-50 POPS FURTHER WEST. THANKS TO EXTENSIVE
CLOUD COVER AND THE SHOWERS, HIGH TEMPERATURES TODAY WILL BE
SEVERAL DEGREES COOLER THAN YESTERDAY...RANGING FROM THE MIDDLE TO
UPPER 60S EAST OF I-55...TO THE LOWER 70S IN THE ILLINOIS RIVER
VALLEY. THE BAND OF SCATTERED SHOWERS WILL GRADUALLY SHIFT
EASTWARD INTO INDIANA THIS EVENING, RESULTING IN AN OVERALL LULL
IN PRECIP CHANCES ACROSS CENTRAL ILLINOIS TONIGHT.
ATTENTION THEN TURNS TO AN AREA OF LOW PRESSURE EXPECTED TO TRACK
FROM NEAR KANSAS CITY THIS EVENING TO LAKE HURON BY SUNDAY
EVENING. A BROKEN LINE OF SHOWERS/STORMS WILL DEVELOP ALONG THE
TRAILING COLD FRONT THIS EVENING, WITH THE REMNANTS OF THIS
CONVECTION PUSHING TOWARD WESTERN ILLINOIS BY DAWN SUNDAY.
FORECAST SOUNDINGS AHEAD OF THIS ACTIVITY CONTINUE TO INDICATE A
STRONGLY CAPPED BOUNDARY LAYER, SUGGESTING THE STORMS WILL BE IN A
WEAKENING TREND AS THEY PUSH INTO THE MORE UNFAVORABLE
ENVIRONMENT ACROSS ILLINOIS. THINK THERE WILL BE ENOUGH ELEVATED
INSTABILITY TO SUPPORT THE POTENTIAL FOR SMALL HAIL/GUSTY WINDS
WITH A FEW OF THE CELLS ALONG/WEST OF I-55 SUNDAY MORNING:
HOWEVER, THE SEVERE WEATHER THREAT WILL REMAIN QUITE LOW.
AS THE LOW LIFTS INTO WISCONSIN AND THE COLD FRONT CROSSES THE
MISSISSIPPI RIVER, A RENEWED ROUND OF CONVECTION WILL DEVELOP
SUNDAY AFTERNOON. AS HAS BEEN NOTED BY THE PAST SEVERAL MODEL
RUNS, A MODERATELY UNSTABLE/HIGHLY SHEARED ENVIRONMENT IS EXPECTED
AHEAD OF THE COLD FRONT. 00Z HREF SHOWS ENSEMBLE MEAN SBCAPES IN
THE 1500-2000J/KG RANGE EAST OF THE I-55 CORRIDOR...WHILE NAM
0-6KM BULK SHEAR INCREASES TO 50-60KT. SOUNDINGS SUGGEST ONLY
MINOR DIRECTIONAL SHEAR, BUT PRONOUNCED SPEED SHEAR AS A MID-LEVEL
JET STREAK PUSHES ACROSS THE REGION. THIS CONTRIBUTES TO
IMPRESSIVE 0-3KM VGP VALUES OF 0.5 TO 0.6...HIGHLY SUPPORTIVE OF
SUPERCELL DEVELOPMENT. GIVEN FAVORABLE DYNAMICS AND KINEMATICS, IT
APPEARS THAT SUPERCELLS WILL RAPIDLY DEVELOP AHEAD OF THE FRONT
BY PEAK HEATING...THEN GRADUALLY CONGEAL INTO A BROKEN LINE BY
LATE AFTERNOON/EARLY EVENING AS THEY SHIFT INTO THE OHIO RIVER
VALLEY. THE EXACT LOCATION WHERE THE CELLS WILL INITIALLY FIRE IS
STILL SOMEWHAT IN QUESTION: HOWEVER, THE 00Z CAMS STRONGLY SUGGEST
LOCATIONS ALONG OR JUST EAST OF I-55 BY AROUND MIDDAY. SPC
CONTINUES TO HIGHLIGHT MOST OF CENTRAL ILLINOIS EAST OF THE
ILLINOIS RIVER WITH AN ENHANCED RISK FOR SEVERE WEATHER: HOWEVER,
IF CURRENT TRENDS CONTINUE...THINK THE GREATEST RISK WILL BE
FOCUSED MOSTLY EAST OF I-55 BETWEEN NOON AND 6PM...THEN
ALONG/SOUTH OF I-70 FROM 4PM TO 10PM. DAMAGING WIND GUSTS, LARGE
HAIL, AND A FEW TORNADOES WILL BE POSSIBLE WITH THE STORMS.
BARNES
LONG TERM
(MONDAY THROUGH FRIDAY)
ISSUED AT 354 AM CDT SAT MAR 29 2025
THE COLD FRONT WILL SWING THROUGH CENTRAL ILLINOIS SUNDAY NIGHT,
BRINGING AN END TO THE SEVERE WEATHER RISK AND INTRODUCING A BRIEF
SHOT OF SHARPLY COLDER WEATHER FOR EARLY NEXT WEEK. AFTER HIGHS IN
THE 70S ON SUNDAY, READINGS WILL FALL INTO THE UPPER 40S TO AROUND
50 ON MONDAY...WITH FROSTY LOWS AT OR BELOW FREEZING MONDAY NIGHT.
AFTER THAT, THE ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH NEXT
WEEK. DRY CONDITIONS WILL PREVAIL MONDAY/TUESDAY BEFORE YET
ANOTHER STRONG STORM SYSTEM APPROACHES FROM THE SOUTHWEST TUESDAY
NIGHT INTO WEDNESDAY. WHILE IT IS STILL TOO EARLY TO PROPERLY
ASSESS ANY ATTENDANT SEVERE WEATHER RISK, SPC IS HIGHLIGHTING A
LARGE SWATH OF THE MIDWEST/OHIO RIVER VALLEY WITH A 15%
PROBABILITY OF SEVERE ON WEDNESDAY. ONCE THE SYSTEM PASSES, THE
MAIN BAROCLINIC ZONE WILL DROP SOUTHWARD AND STALL ACROSS THE OHIO
RIVER VALLEY AS IT BECOMES PARALLEL WITH THE DEEP-LAYER
SOUTHWESTERLY FLOW PATTERN DEVELOPING ACROSS THE CENTRAL/EASTERN
U.S. AS A SERIES OF WAVES INTERACTS WITH THE BOUNDARY, ADDITIONAL
ROUNDS OF SHOWERS/STORMS WILL BE POSSIBLE BY THE END OF THE WEEK.
THE END RESULT WILL BE A WET AND UNSETTLED EXTENDED FORECAST.
BARNES
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1235 PM CDT SAT MAR 29 2025
PREDOMINANTLY MVFR CEILINGS WITH PERIODS OF IFR WITH SHOWERS IS
EXPECTED THROUGH THE AFTERNOON, WITH MORE WIDESPREAD AND
PERSISTENT IFR CEILINGS OVERNIGHT. HREF GUIDANCE SUGGESTS CHANCES
FOR IFR CEILINGS (50-80%) INCREASE DRAMATICALLY FROM SOUTH TO
NORTH ACROSS THE AIRFIELDS BETWEEN ROUGHLY 03Z AND 06Z (10PM TO
1AM CDT). WHILE A BREAK IN RAIN IS FORECAST OVERNIGHT, ADDITIONAL
PRECIPITATION IS EXPECTED TOMORROW WITH SOME CHANCE FOR
THUNDERSTORMS BEGINNING AROUND THE END OF THE FORECAST PERIOD,
ESPECIALLY AT DEC AND CMI. THERE MAY BE A SHARP UPTICK IN
SOUTHWEST WINDS NEAR THE END OF THE FORECAST PERIOD BEHIND A
DECAYING MCV, BUT CONFIDENCE WAS TOO LOW TO ADD THAT TO THE TAFS
AT THIS JUNCTURE.
BUMGARDNER
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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