623
FXUS63 KILX 010414
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1014 PM CST SAT FEB 28 2026
KEY MESSAGES
- LIGHT WINTRY PRECIP REMAINS POSSIBLE SUNDAY NIGHT INTO MONDAY.
SNOW AMOUNTS WILL GENERALLY BE LESS THAN 1", BUT THERE IS A LOW
CHANCE (20-30%) OF A NARROW CORRIDOR OF SLEET/FREEZING RAIN FROM
NEAR JACKSONVILLE TO ROBINSON.
- A PATTERN CHANGE WILL BRING WARMER AND WETTER CONDITIONS TO THE
MIDWEST NEXT WEEK. BENEFICIAL RAINFALL IS LIKELY, WITH A 60-80%
CHANCE FOR OVER AN INCH OF RAIN THROUGH THURSDAY. THERE MAY BE
PERIODS OF STRONG TO SEVERE THUNDERSTORMS, WITH THE FIRST CHANCE
BEING ON WEDNESDAY (5 TO 15% CHANCE).
DISCUSSION
ISSUED AT 215 PM CST SAT FEB 28 2026
*** SHORT TERM ***
MUCH OF THE SHORT TERM FORECAST REMAINS ON TRACK. A VERY WEAK SFC
LOW WAS POSITIONED NEAR TOPEKA, KS, AT OF 1245PM/1845Z, WITH A
FRONTAL BOUNDARY EXTENDING EASTWARD NEAR THE US-36/I-72 CORRIDOR.
WITH THIS FRONT BISECTING THE ILX CWA, A BROAD RANGE IN TEMPS
EXISTS, WITH MID 40S AT GALESBURG AND UPPER 50S SOUTH OF I-70.
LOW- LEVEL WAA MAY INITIATE A FEW LIGHT SHOWERS LATE
AFTERNOON/EARLY EVENING SOUTHEAST OF THE I-72 CORRIDOR (15-20%
CHANCE), BUT VERY DRY LOW LEVELS ON FORECAST SOUNDINGS SUGGEST
MORE VIRGA THAN PRECIP REACHING THE SFC.
THE WEAK SFC LOW/FRONTAL ZONE WILL BE SHUNTED SOUTH TONIGHT AS A
STRONG SFC HIGH STRENGTHS OVER THE GREAT LAKES/UPPER MIDWEST.
PERSISTENT NORTHEASTERLY WINDS WILL CONTINUE OVERNIGHT (GUSTS OF
20- 25 MPH). LOW-LEVEL FLOW OFF LAKE MICHIGAN COULD LEAD TO SOME
LAKE- ENHANCED LOW CLOUD COVER EARLY SUNDAY MORNING (BEST CHANCE
ACROSS THE NORTHERN HALF OF THE FORECAST AREA). RAP 925MB RH FIELD
SEEM TO CAPTURE THIS POTENTIAL WELL. THIS IS MORE OF AN AVIATION
FORECAST CONCERN THAN ANYTHING ELSE, AS PARTLY TO MOSTLY CLOUDY
SKIES ARE EXPECTED ON SUNDAY REGARDLESS.
*** WINTER PRECIP LATE WEEKEND ***
A SYSTEM REMAINS ON TRACK TO BRING LIGHT WINTRY PRECIP TO THE
REGION SUNDAY EVENING INTO MONDAY MORNING. THE SOUTHWARD AND
WEAKER TREND CONTINUES, HOWEVER, LATEST FORECAST SOUNDINGS SUGGEST
THAT A CORRIDOR OF ICY P-TYPES MAY OCCUR. IT'S STILL A
CHALLENGING FORECAST. CAM SOUNDINGS VARY ON THE STRENGTH OF THE
WARM NOSE, BUT ALL SHOW A 'NEGATIVE ENERGY' (BELOW FREEZING) LAYER
NEAR THE SURFACE. SURFACE TEMPS AND SFC WET-BULB TEMPS WILL BE
NEAR OR SLIGHTLY ABOVE FREEZING WITHIN THIS CORRIDOR, AND GROUND
TEMPS ARE ON THE WARM SIDE AFTER AIR TEMPS IN THE 70S YESTERDAY.
CONSIDERED ADDING MENTION OF ICY P-TYPES IN A CORRIDOR FROM ABOUT
JACKSONVILLE TO ROBINSON, BUT HELD OFF FOR NOW GIVEN SMALL
VARIATIONS IN THE THE MODEL TEMPERATURE PROFILE WILL CHANGE THE
P-TYPE FORECAST. I WOULD ALSO LIKE TO SEE A MORE CONSISTENT SIGNAL
FROM RUN-TO-RUN OF THE MODELS BEFORE LATCHING ON AND INCLUDING
ICE IN THE FORECAST.
THE PROBABILITY OF AT LEAST ONE INCH OF SNOW IS DOWN TO JUST 20%
ALONG THE I-74 CORRIDOR, AND PEAKS AT 30-40% IN AREAS SOUTH OF A
MACOMB TO DECATUR LINE. THESE VALUES CONTINUE TO FOLLOW A DOWNWARD
TREND FROM PREVIOUS FORECASTS. THE PROBABILITY OF AT LEAST 0.01"
OF ICE ACCUMULATION IS 20-30% ALONG AND SOUTH OF JACKSONVILLE TO
ROBINSON LINE, WITH CHANCES DECREASING QUICKLY TO THE NORTH.
*** A WET PATTERN DEVELOPS ***
AS DISCUSSED OVER THE LAST SEVERAL DAYS, A BROAD SYNOPTIC PATTERN
SHIFT IS ANTICIPATED NEXT WEEK, RESULTING IN FREQUENT LOW PRESSURE
SYSTEMS/ASSOCIATED FRONTAL BOUNDARIES INTERACTING WITH RICH
MOISTURE TO PRODUCE NUMEROUS RAIN CHANCES.
RAIN CHANCES BEGIN MON NIGHT AS WAA OVERSPREADS THE REGION IN
RESPONSE TO A DEVELOPING SYSTEM OVER THE PLAINS. A STALLED FRONTAL
BOUNDARY IS EXPECTED TO BE DRAPED EAST-WEST SOMEWHERE ACROSS THE
STATE FROM TUES AM THROUGH WED AM. THE EXACT PLACEMENT REMAINS IN
FLUX, WITH LATEST ENSEMBLE GUIDANCE TRENDING NORTHWARD (INCREASING
THE RAIN CHANCES NORTH OF I-72 RELATIVE TO PREVIOUS FORECASTS).
ENS PWATS ARE ABOVE THE 95TH PERCENTILE OF THE MODEL CLIMATOLOGY,
SO THERE WILL BE AMPLE MOISTURE INTERACTING WITH THIS FRONT, AND
CLOUD LAYER WINDS ARE ORIENTED CLOSE TO PARALLEL TO THE FRONT.
INTO WED, MODELS SHOW A POTENT SHORTWAVE LIFTING TOWARDS IL.
DEPENDING ON THE TRACK OF THE SFC LOW/WARM SECTOR PLACEMENT, THIS
COULD SUPPORT A SEVERE STORM THREAT, ALTHOUGH MODELS STILL VARY
THIS FAR IN ADVANCE. CSU-MLP CONTINUES TO HIGHLIGHT A 5-15% CHANCE
OF SEVERE STORMS ACROSS THE REGION ON WEDNESDAY. AT ANY RATE,
EXPECTED CONTINUED PERIODS OF SHOWERS/STORMS ON WED.
FROM MONDAY MORNING THROUGH THURSDAY, THERE IS A 60-80% CHANCE FOR
1" OF PRECIPITATION AREA-WIDE, AND A 20-40% CHANCE OF OVER 2" AT
ANY GIVEN LOCATION. ADDITIONAL RAIN CHANCES EXIST LATE NEXT WEEK
INTO THE FOLLOWING WEEK, AS THIS GENERAL SYNOPTIC PATTERN
PERSISTS.
ERWIN
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1014 PM CST SAT FEB 28 2026
MVFR CEILINGS CURRENTLY OVER NORTHERN IL TO NW INDIANA, ARE
FORECAST TO SHIFT SOUTHWEST TONIGHT, DUE TO NORTHEAST WINDS IN THE
LOWER ATMOSPHERE. MUCH OF THE GUIDANCE NOW FAVORS KBMI-KCMI-KDEC
TO TO SEE THE MVFR CEILINGS LATE TONIGHT INTO SUNDAY MORNING. WITH
LOWER PROBABILITIES OF MVFR CEILINGS AT KPIA-KSPI, ONLY WENT WITH
A SCT025 GROUP THERE. NORTHEAST WINDS WILL BE PERSISTENT THROUGH
THE FORECAST, SUSTAINED AT 10-15 KT WITH OCCASIONAL GUSTS AROUND
20 KT. A WEATHER SYSTEM MOVING IN FROM THE WEST SUNDAY EVENING
WILL SPREAD -SN AND MVFR CEILINGS BACK INTO CENTRAL IL. HIGHER
PROBABILITIES OF MVFR CONDITIONS ARE FAVORED FOR THE KSPI-KDEC-
KCMI CORRIDOR.
25
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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