165
FXUS63 KILX 021753
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1253 PM CDT SAT MAY 2 2026
KEY MESSAGES
- PATCHY FROST IS FORECAST NEAR AND EAST OF I-57 TONIGHT. WHILE
THE CHANCE IS LOW (20-40%), THOSE WITH TENDER VEGETATION
SHOULD CONSIDER COVERING THEIR PLANTS TO PREVENT DAMAGE.
- SCATTERED THUNDERSTORMS ARE FORECAST MONDAY INTO WEDNESDAY.
THERE IS A LOW (5-14%) CHANCE OF A SEVERE THUNDERSTORM BOTH
SUNDAY AND MONDAY INTO MONDAY NIGHT.
DISCUSSION
ISSUED AT 141 AM CDT SAT MAY 2 2026
***** COOL WITH A FEW SHOWERS IN SOUTHEAST IL TODAY *****
AT 130AM, THE AXIS OF A SHORTWAVE TROUGH EXTENDED FROM ONTARIO
SOUTHWEST INTO THE CENTRAL PLAINS. AHEAD OF THIS FEATURE, A FEW
SHOWERS LINGER IN SOUTHEAST ILLINOIS, WHILE SCATTERED CLOUDS ARE
PRESENT ELSEWHERE. THIS WILL LIMIT RADIATIONAL LOSSES THROUGH THE
MORNING, THOUGH PATCHY FROST IS POSSIBLE (15-30% CHANCE) IN AREAS
THAT SEE THE MOST BREAKS IN THIS CLOUD COVER, WITH THE HIGHEST
CHANCES NEAR AND NORTH OF ROUGHLY I-74.
WITH 850MB TEMPERATURES PLUNGING TO AROUND -2 DEGC THIS AFTERNOON
AND NUMEROUS DIURNAL CUMULUS LIMITING SURFACE HEATING, TEMPERATURES
ARE FORECAST TO CLIMB ONLY INTO THE MID TO UPPER 50S - AROUND 15
DEGREES BELOW NORMAL FOR EARLY MAY. WITH CLOUD COVER DIMINISHING IN
THE EVENING, TEMPERATURES MAY FALL ENOUGH OVERNIGHT TO RESULT IN
PATCHY FROST IN EAST-CENTRAL ILLINOIS, THOUGH AS SURFACE HIGH
PRESSURE SHIFTS SOUTHEASTWARD DURING THE NIGHT WINDS WILL RETURN
FROM THE SOUTHWEST. THE NATIONAL BLEND OF MODELS (NBM) ADVERTISES A
20-50% CHANCE OVERNIGHT LOW TEMPERATURES FALL BELOW 36 DEGF SOUTH OF
I-72 IN EAST-CENTRAL ILLINOIS, SO A MENTION OF PATCHY FROST WAS
ADDED TO THE FORECAST THERE, THOUGH WE'D WANT TO SEE CONFIDENCE COME
UP BEFORE PULLING THE TRIGGER ON A FROST ADVISORY.
***** WARMER, FEW STORMS, EARLY NEXT WEEK *****
TOMORROW INTO MONDAY, THE UPPER LEVEL TROUGH RESPONSIBLE FOR OUR
COOL, SHOWERY WEATHER OVER THE PAST SEVERAL DAYS WILL FINALLY LIFT
NORTHWARD INTO THE HUDSON BAY, WHILE ANOTHER SHORTWAVE DIVES
SOUTHEAST ACROSS THE UPPER MIDWEST AND GREAT LAKES. THIS COMBINATION
WILL PROMOTE SOUTHWESTERLY FLOW OVER THE LOCAL AREA AHEAD OF A WEAK
COLD FRONT ON SUNDAY, ALLOWING TEMPERATURES TO CLIMB INTO THE 70S.
THE JURY'S OUT ON WHETHER OR NOT THIS FRONT WILL PROVIDE SUFFICIENT
LIFT TO TRIGGER SHOWERS AND STORMS SUNDAY AFTERNOON, BUT THE CHANCE
APPEARS LOW WITH THE NAMNEST THE ONLY CAM DEPICTING STORMS. NBM/LREF
(LOW RESOLUTION ENSEMBLE FORECAST) ENSEMBLE MEAN DEPICT SEVERAL
HUNDRED J/KG OF SBCAPE (HIGHEST SOUTHWEST) ALONG WITH 45-55 KT OF
0-6KM SHEAR, WHICH WOULD ALLOW ANY STORM THAT DOES FORM TO
BECOME STRONG. EVEN SO, SPC'S DAY 2 OUTLOOK WOULD SUGGEST THE
CHANCE IS LOW (5-14%).
THE FRONT IS FORECAST TO STALL OVER OUR AREA SUNDAY NIGHT, AND
LINGER THROUGH AT LEAST TUESDAY NIGHT. WITH MOISTURE CONVERGENCE AND
A SERIES OF WEAK DISTURBANCES RIDING ALONG THE BOUNDARY, PERIODS OF
SHOWERS AND STORMS ARE LIKELY (50-70% CHANCE). WITH ANY BREAKS IN
CLOUD COVER, A FEW THOUSAND J/KG SBCAPE COULD MATERIALIZE NEAR AND
SOUTH OF THE FRONT ON MONDAY, POTENTIALLY FUELING A COUPLE STRONGER
STORMS THAT COULD GENERATE LOCALLY SEVERE HAIL AND/OR WIND. HOWEVER,
CONFIDENCE IN THIS IS LOW DUE TO WEAK FORCING. THE BEST OPPORTUNITY
FOR STORMS MIGHT ACTUALLY COME MONDAY NIGHT AS THE LLJ RAMPS UP OVER
THE AREA. SPC HAS OUR ENTIRE AREA OUTLOOKED IN A LEVEL 1 OF 5
(MARGINAL) RISK FOR SEVERE WEATHER.
***** BELOW NORMAL TEMPS RETURN MID WEEK *****
A STRONGER SHORTWAVE TROUGH IS FORECAST TO ARRIVE ON WEDNESDAY,
GIVING THE AREA A STRONGER PUSH OF COOL ADVECTION. THE LREF GIVES A
30-50% CHANCE THAT 850MB TEMPERATURES DROP BELOW -2 DEGC, WHICH
WOULD FAVOR HIGH (LOW) TEMPERATURES IN THE MID-UPPER 50S (UPPER 30S
TO LOW 40S) WEDNESDAY AND THURSDAY. THE PARENT UPPER LEVEL TROUGH IS
FORECAST TO PARK ITSELF OVER THE GREAT LAKES AND NORTHEAST LATE NEXT
WEEK, WHICH WOULD FOSTER PERPETUAL COOL, NORTHWEST FLOW ACROSS THE
MIDWEST. WPC'S CLUSTER ANALYSIS SUGGESTS THE GREATEST SOURCE OF
UNCERTAINTY IS IN THE SIZE/AMPLITUDE OF THIS UPPER LEVEL TROUGH
HEADING INTO NEXT WEEKEND. ABOUT 30% OF MODELS HAVE ABOVE OR NEAR
NORMAL TEMPERATURES, WHILE THE REMAINING 70% DEPICT SOME FLAVOR
OR BELOW NORMAL; FOR REFERENCE, TYPICAL HIGHS IN EARLY MAY ARE
IN THE LOW-MID 70S. GIVEN LACK OF DEEP-LAYER MOISTURE IN THIS
NORTHWEST FLOW REGIME, HEAVY RAINFALL WOULD NOT BE FAVORED,
THOUGH A FEW LIGHT SHOWERS WILL BE POSSIBLE (10-25% CHANCE) WITH
ANY SHORTWAVES PASSING THROUGH THE AREA.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1253 PM CDT SAT MAY 2 2026
BKN COVERAGE OF DIURNAL CUMULUS AROUND 6000 FT AGL WILL
CONTINUE UNTIL THIS EVENING, THEN DISSIPATE AS HIGH CLOUDS
APPROACH AHEAD OF A WEATHER SYSTEM THAT COULD BRING SCATTERED
SHOWERS AROUND 13Z-18Z MONDAY. VFR CONDITIONS EXPECTED THROUGH
THE PERIOD, WITH VERY LOW PROBABILITIES OF BELOW 5 MILE VSBY OR
3000 FT CIGS IN SHRA MONDAY. WINDS NW-NE UNDER 10 KTS THIS
AFTERNOON, BECOMING LIGHT AND VARIABLE BY 01Z. SW WINDS
INCREASING OVERNIGHT AND BECOMING 10-15 KTS WITH GUSTS 20-25 KTS
BY 15Z.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BUMGARDNER
DISCUSSION...BUMGARDNER
AVIATION...37
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