100
FXUS63 KILX 010853
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
353 AM CDT TUE APR 1 2025
KEY MESSAGES
- A FEW THUNDERSTORMS WILL DEVELOP TONIGHT AS A WARM FRONT LIFTS
THROUGH THE REGION. THE STORMS WILL BE MOST NUMEROUS ALONG AND
NORTHWEST OF A SPRINGFIELD TO CHAMPAIGN LINE WHERE A LOW
PROBABILITY (5-15% CHANCE) FOR 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 AND FLOODING ISSUES ALONG AND SOUTH OF
I-70...WHERE A FLOOD WATCH IS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH SUNDAY MORNING.
DISCUSSION
ISSUED AT 353 AM CDT TUE APR 1 2025
..SCATTERED THUNDERSTORMS TONIGHT
00Z APR 1 CAMS ALL INDICATE SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING TONIGHT AS A WARM FRONT LIFTS NORTHWARD INTO THE AREA.
WHILE INSTABILITY WILL INITIALLY BE ABSENT THIS EVENING, NAM
SHOWS MUCAPE VALUES INCREASING TO OVER 1000J/KG AFTER MIDNIGHT.
FORECAST SOUNDINGS SHOW A STRONGLY CAPPED BOUNDARY LAYER, WITH
STEEP MID-LEVEL LAPSE RATES AND INCREASING ELEVATED INSTABILITY
OVERNIGHT. WHILE ORGANIZED SEVERE WEATHER IS NOT LIKELY, A FEW OF
THE CELLS WILL BE CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL (UP
TO PENNY-SIZED) AND GUSTY WINDS. BASED ON MODEL CONSENSUS, THINK
THE BEST CHANCE FOR STORMS WILL FOCUS ALONG/NORTHWEST OF A
SPRINGFIELD TO CHAMPAIGN LINE OVERNIGHT.
..SEVERE WEATHER OUTBREAK ON WEDNESDAY
AS HAS BEEN ADVERTISED FOR THE PAST SEVERAL DAYS, WEDNESDAY
CONTINUES TO LOOK LIKE A VOLATILE DAY ACROSS PARTS OF CENTRAL
ILLINOIS AS A STRONG COLD FRONT INTERACTS WITH A MODERATELY
UNSTABLE AND STRONGLY SHEARED ENVIRONMENT. THE OVERALL SET-UP HAS
MANY SIMILARITIES TO WHAT TRANSPIRED ON SUNDAY, MARCH 30: HOWEVER,
THE DEEP-LAYER SHEAR IS STRONGER DUE TO A POWERFUL LOW-LEVEL JET
PROGGED TO DEVELOP FROM THE OZARKS NORTHEASTWARD INTO THE GREAT
LAKES LATE TONIGHT INTO WEDNESDAY. 00Z NAM SHOWS THE CORE OF THE
JET PEAKING AT 75-80KT, THUS CONTRIBUTING TO 60-80KT OF 0-6KM BULK
SHEAR. WHILE THE BOUNDARY LAYER WILL INITIALLY BE CAPPED, AS
TEMPERATURES WARM AND THE CAP IS BROKEN, SOME OF THIS MOMENTUM
WILL BE MIXED TO THE SURFACE FROM AROUND MIDDAY THROUGH THE
AFTERNOON. NBM GUSTS SEEMED WAY TOO LOW GIVEN THE EXTREMELY STRONG
JET, SO USED THE HIGHER CONSSHORT GUIDANCE TO GET GUSTS OF
45-50MPH ALONG/EAST OF I-55. WOULD NOT BE SURPRISED TO SEE GUSTS
EVEN HIGHER THAN THIS...AND A WIND ADVISORY OR POSSIBLY EVEN A
HIGH WIND WARNING MAY BE WARRANTED IF TRENDS CONTINUE.
00Z CAMS SHOW A LINE OF CONVECTION DEVELOPING ALONG AN ADVANCING
COLD FRONT ACROSS EASTERN NEBRASKA/KANSAS TONIGHT...THEN PUSHING
EASTWARD TO THE MISSISSIPPI RIVER TOWARD DAWN WEDNESDAY. THINK
THIS INITIAL SURGE OF STORMS WILL WEAKEN ONLY SLIGHTLY AS IT
TRACKS INTO THE WESTERN KILX CWA DURING THE MORNING, THUS LEADING
TO A LOW RISK FOR DAMAGING WIND GUSTS AND HAIL ALONG/WEST OF I-55.
WHILE MODEL SOLUTIONS VARY, CONSENSUS SUGGESTS CONVECTION WILL
RE-INTENSIFY AND BECOME SURFACE-BASED ALONG THE RESULTING OUTFLOW
BOUNDARY BY MIDDAY. IT APPEARS THIS PROCESS WILL MOST LIKELY
OCCUR JUST EAST OF THE I-55 CORRIDOR ALMOST EXACTLY AS IT DID THIS
PAST SUNDAY. THE RENEWED CONVECTION WILL THEN BE ABLE TO INTERACT
WITH THE FAVORABLE ENVIRONMENT TO PRODUCE DAMAGING WIND GUSTS IN
EXCESS OF 70MPH, HAIL LARGER THAN QUARTERS, AND A FEW
TORNADOES...PARTICULARLY ALONG/EAST OF A SHELBYVILLE TO CHAMPAIGN
LINE FROM EARLY AFTERNOON THROUGH EARLY EVENING. A SEVERE RISK
WILL LIKELY LINGER ALONG/SOUTH OF I-70 THROUGH MID-EVENING BEFORE
THE MOST SIGNIFICANT CONVECTION DEPARTS INTO INDIANA.
..FLOOD RISK ACROSS SOUTHEAST ILLINOIS
THE COLD FRONT WILL SETTLE SOUTHWARD AND STALL ACROSS THE OHIO
RIVER VALLEY WEDNESDAY NIGHT AS IT BECOMES PARALLEL TO THE UPPER
LEVEL FLOW. THE BOUNDARY 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 INDICATES 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 APR 1 ECMWF EFI FOR QPF FOCUSES VALUES IN EXCESS OF 0.8 NEAR
THE OHIO RIVER BOTH WEDNESDAY NIGHT AND THURSDAY NIGHT, THEN
SHIFTS THOSE VALUES NORTHWARD TO THE I-72 CORRIDOR FOR FRIDAY
NIGHT INTO SATURDAY. CURRENT WPC QPF FORECAST KEEPS THE MOST
EXTREME RAINFALL AMOUNTS MOSTLY 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 ACROSS THE ILLINOIS RIVER VALLEY. DUE TO INCREASING
CONFIDENCE FOR EXCESSIVE RAINFALL AND FLOODING, A FLOOD WATCH WILL
REMAIN IN EFFECT FOR LOCATIONS ALONG/SOUTH OF I-70 FROM WEDNESDAY
AFTERNOON THROUGH SUNDAY MORNING.
BARNES
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1206 AM CDT TUE APR 1 2025
HIGH PRESSURE SHIFTING EAST OF THE AREA THIS MORNING WILL ALLOW
SOUTHEAST WINDS TO DEVELOP, WITH GUSTS NEAR 25 KT BEGINNING LATE
MORNING AND CONTINUING THROUGH 06Z. HIGH CLOUDS WILL DOMINATE THE
REGION TODAY. SCATTERED SHOWERS ARE EXPECTED TO DEVELOP THIS
EVENING ALONG WITH A FEW STORMS, SO INCLUDED PROB30 -TSRA 02-06Z.
25
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH SUNDAY MORNING FOR
ILZ062-063-066>068-071>073.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page