559
FXUS63 KILX 311726
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1226 PM CDT MON MAR 31 2025
KEY MESSAGES
- A FEW THUNDERSTORMS WILL DEVELOP TUESDAY NIGHT AS A WARM FRONT
LIFTS THROUGH THE REGION. THE STORMS WILL BE MOST NUMEROUS
ALONG/WEST OF I-55 WHERE A LOW PROBABILITY (15% CHANCE) FOR
DAMAGING WIND GUSTS AND LARGE HAIL EXISTS AFTER MIDNIGHT.
- A MORE SIGNIFICANT SEVERE WEATHER EVENT WILL UNFOLD ON
WEDNESDAY. THE LATEST SPC OUTLOOK INDICATES AN ENHANCED RISK
(LEVEL 3 OF 5) FOR DAMAGING WIND GUSTS, LARGE HAIL, AND
TORNADOES.
- MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL LEAD TO A RISK
FOR EXCESSIVE RAINFALL ALONG/SOUTH OF I-70 WEDNESDAY NIGHT
THROUGH SATURDAY.
SHORT TERM
(TODAY THROUGH TUESDAY)
ISSUED AT 343 AM CDT MON MAR 31 2025
08Z/3AM SURFACE ANALYSIS SHOWS A COLD FRONT FROM THE EASTERN
GREAT LAKES TO THE TENNESSEE RIVER VALLEY WHILE A RIDGE OF HIGH
PRESSURE BUILDS INTO THE PLAINS. DESPITE FROPA, WIDESPREAD LOW
CLOUDS BLANKET CENTRAL ILLINOIS...WITH THE BACK EDGE OF THE CLOUD
SHIELD OVER NORTHERN IOWA. TIMING OF THE CLEARING TREND WILL BE A
BIT TRICKY TODAY:HOWEVER, BASED ON THE LATEST SATELLITE TRENDS
SHOWING CLOUDS BEGINNING TO SCATTER ACROSS CENTRAL IOWA, THINK
SKIES WILL BECOME PARTLY SUNNY ACROSS THE ILLINOIS RIVER VALLEY BY
MID-MORNING THEN FURTHER EAST TO THE I-55 CORRIDOR BY AROUND MIDDAY.
FURTHER EAST, CLOUDS WILL HOLD FIRM UNTIL GRADUALLY SCATTERING
DURING THE AFTERNOON. THANKS TO CLOUD COVER AND BRISK NORTHWESTERLY
WINDS GUSTING 15-25MPH, HIGH TEMPERATURES WILL BE SEVERAL DEGREES
BELOW NORMAL FOR THIS TIME OF YEAR IN THE UPPER 40S AND LOWER
50S. AS THE HIGH SHIFTS EASTWARD AND WINDS BECOME LIGHT/VARIABLE,
RADIATIONAL COOLING WILL ALLOW LOWS TONIGHT TO BOTTOM OUT IN THE
UPPER 20S AND LOWER 30S. ANY SENSITIVE OUTDOOR PLANTS SHOULD BE
PROTECTED OR BROUGHT INSIDE TO AVOID POSSIBLE DAMAGE. AFTER A
SUNNY START TO THE DAY, CLOUDS WILL BE ON THE INCREASE FROM WEST
TO EAST DURING THE DAY TUESDAY AS HIGH TEMPERATURES CLIMB INTO THE
MIDDLE TO UPPER 50S.
BARNES
LONG TERM
(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 343 AM CDT MON MAR 31 2025
THE NEXT SIGNIFICANT STORM SYSTEM TO IMPACT THE MIDWEST WILL BEGIN
TO APPROACH FROM THE WEST TUESDAY NIGHT. A POWERFUL 850MB JET WILL
DEVELOP IN ADVANCE OF THE SYSTEM FROM THE SOUTHERN PLAINS INTO
IOWA/ILLINOIS OVERNIGHT, WITH THE 00Z NAM SHOWING THE CORE OF THE
JET INCREASING TO 60-70KT. WITH RAPID MOISTURE RETURN FROM THE
WESTERN GULF, CORRESPONDING MUCAPE VALUES WILL EXCEED 1000J/KG.
GIVEN AMPLE ELEVATED INSTABILITY AND STEEPENING LAPSE RATES, THINK
SCATTERED STORMS ASSOCIATED WITH A WARM FRONT LIFTING NORTHWARD
THROUGH CENTRAL ILLINOIS WILL BE CAPABLE OF PRODUCING GUSTY WINDS
AND HAIL. THE STORMS WILL BE MOST NUMEROUS ACROSS THE WESTERN HALF
OF THE KILX CWA...ESPECIALLY ALONG/WEST OF I-55 WHERE SPC INDICATES
A SLIGHT RISK FOR SEVERE AFTER MIDNIGHT.
ONCE THE OVERNIGHT CONVECTION LIFTS NORTHWARD, CENTRAL ILLINOIS
WILL PUNCH INTO THE WARM SECTOR OF THE SYSTEM WITH STRONG/GUSTY
SOUTHERLY WINDS BOOSTING TEMPERATURES INTO THE 70S AND SURFACE
DEWPOINTS INTO THE LOWER TO MIDDLE 60S ON WEDNESDAY. CORRESPONDING
SBCAPE VALUES WILL REACH THE 1500-2000J/KG RANGE FROM MIDDAY
THROUGH THE AFTERNOON. MEANWHILE POWERFUL WINDS ALOFT WILL
CONTRIBUTE TO 0-6KM BULK SHEAR VALUES OF 60-80KT. WHILE SURFACE
LOW PRESSURE WILL TRACK WELL NW OF ILLINOIS, ITS TRAILING COLD
FRONT WILL INTERACT WITH THE MODERATELY UNSTABLE/HIGHLY SHEARED
ENVIRONMENT TO TRIGGER A POTENTIALLY SIGNIFICANT SEVERE WEATHER
EVENT. SUPERCELL THUNDERSTORMS WILL DEVELOP ALONG THE FRONT AND/OR
OUTFLOW LEFT BEHIND BY THE OVERNIGHT STORMS ACROSS THE ILLINOIS
RIVER VALLEY BY LATE MORNING...THEN WILL CONGEAL INTO A LINE AND SHIFT
EASTWARD ACROSS THE REMAINDER OF CENTRAL ILLINOIS DURING THE
AFTERNOON INTO THE EARLY EVENING. ALL SEVERE HAZARDS WILL BE IN
PLAY WITH THESE STORMS...INCLUDING DAMAGING WIND GUSTS, LARGE
HAIL, AND TORNADOES. STAY TUNED TO LATER FORECASTS FOR MORE
PRECISE DETAILS AND TIMING.
THE COLD FRONT WILL SETTLE SOUTHWARD AND STALL ACROSS THE OHIO
RIVER VALLEY WEDNESDAY NIGHT AS IT BECOMES PARALLEL TO THE UPPER
LEVEL FLOW. AS HAS BEEN ADVERTISED BY THE PAST SEVERAL MODEL RUNS,
THE FRONT WILL REMAIN QUASI-STATIONARY FROM WEDNESDAY NIGHT
THROUGH SATURDAY NIGHT BEFORE A PATTERN CHANGE PUSHES IT WELL
SOUTH OF THE REGION BY SUNDAY. INDIVIDUAL SHORT-WAVE TROUGHS
INTERACTING WITH THE BOUNDARY IN CONJUNCTION WITH THE NOCTURNAL
LOW-LEVEL JET WILL LEAD TO NUMEROUS ROUNDS OF SHOWERS AND
THUNDERSTORMS FOCUSED ACROSS THE OHIO RIVER VALLEY. WHILE THE GFS
TENDS TO KEEP THE FRONT LOCKED IN PLACE AND PRODUCES REPEATED
RAINS OVER THE SAME LOCATIONS, THE ECMWF SUGGESTS THE BOUNDARY
WILL WAVER NORTH/SOUTH, RESULTING IN RAINFALL MORE EVENLY
DISTRIBUTED. WHICHEVER SOLUTION ULTIMATELY VERIFIES, CONSENSUS
SUGGESTS A POTENTIALLY EXTREME RAINFALL EVENT ACROSS THE OHIO
RIVER VALLEY. 00Z MAR 31 ECMWF EFI FOR QPF FOCUSES VALUES IN
EXCESS OF 0.8 ALONG THE OHIO RIVER VALLEY BOTH WEDNESDAY NIGHT AND
THURSDAY NIGHT, THEN SHIFTS THOSE VALUES NORTHWARD TO THE I-70
CORRIDOR FOR FRIDAY NIGHT INTO SATURDAY. CURRENT WPC QPF FORECAST
KEEPS THE MOST EXTREME RAINFALL AMOUNTS SOUTH OF THE KILX CWA
CLOSER TO THE OHIO RIVER: HOWEVER, 7-DAY AMOUNTS POTENTIALLY
GREATER THAN 5 INCHES COME AS FAR NORTH AS I-70. STORM TOTAL
RAINFALL STEADILY DECREASES FURTHER N/NW, WITH 7-DAY ACCUMULATIONS
OF JUST 1-2 INCHES ALONG/NORTHWEST OF I-55. THE BOTTOM LINE: THE
WEDNESDAY THROUGH SATURDAY TIME PERIOD WILL BE DECIDEDLY WET AND
UNSETTLED ACROSS MUCH OF THE REGION.
BARNES
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1226 PM CDT MON MAR 31 2025
A DECK OF MVFR CEILINGS IS MAKING ITS WAY SOUTH AND EAST OF THE
FORECAST AREA RIGHT NOW. CEILINGS AT BMI/CMI SHOULD RECOVER TO
VFR SOON THIS AFTERNOON, WITH PIA/SPI/DEC STARTING WITH VFR
CEILINGS. AT TIMES, THE WINDS WILL BE GUSTY (20-25KTS) OUT OF THE
NORTHWEST AND WILL BECOME LIGHT OVERNIGHT, SHIFTING OUT OF THE
EAST-SOUTHEAST TOMORROW MORNING.
COPPLE
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH SUNDAY MORNING FOR
ILZ062-063-066>068-071>073.
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