123
FXUS63 KILX 150535
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1235 AM CDT FRI MAY 15 2026
KEY MESSAGES
- PERIODIC STORM CHANCES WILL PERSIST THROUGH EARLY NEXT
WEEK...WITH THE GREATEST PROBABILITY FOR CONVECTION FOCUSING
ON SATURDAY...THEN AGAIN LATE MONDAY INTO TUESDAY.
- AFTER A COUPLE MORE MILD DAYS, A PREVIEW OF SUMMER WILL ARRIVE
BY EARLY NEXT WEEK AS HIGHS SOAR WELL INTO THE 80S BY SUNDAY
AND MONDAY.
DISCUSSION
ISSUED AT 254 PM CDT THU MAY 14 2026
*** A FEW STORMS LATE TONIGHT INTO FRIDAY MORNING ***
19Z/2PM WATER VAPOR IMAGERY SHOWS A SHORT-WAVE TROUGH EXTENDING
FROM SOUTHERN SASKATCHEWAN SOUTHWARD TO COLORADO. AS THIS
FEATURE TRACKS EASTWARD AND INTERACTS WITH A 45-55KT 850MB
NOCTURNAL JET, A CLUSTER OF SHOWERS AND THUNDERSTORMS WILL FORM
ACROSS SOUTHERN IOWA/NORTHERN MISSOURI TOWARD MIDNIGHT. 12Z CAMS
HAVE TRENDED A BIT SLOWER AND SLIGHTLY FURTHER SOUTH WITH THE
TRACK OF THE CLUSTER...KEEPING THE BULK OF THE ACTIVITY SOUTH OF
THE I-74 CORRIDOR. IN ADDITION, INSTABILITY PARAMETERS ARE
WEAKER THAN PREVIOUSLY FORECAST, AS EVIDENCED BY NAM MUCAPES OF
ONLY 100-300J/KG ALONG/SOUTHWEST OF A RUSHVILLE TO SPRINGFIELD
LINE BY 12Z/7AM FRIDAY. HAVE UPDATED POPS TO KEEP CONDITIONS DRY
THIS EVENING, FOLLOWED BY CATEGORICAL (80+) POPS ALONG/SOUTH OF
A MACOMB TO LINCOLN LINE AFTER MIDNIGHT. THINK IT WILL MOSTLY
BE SHOWERS WITH AN OCCASIONAL RUMBLE OF THUNDER AND LITTLE TO NO
RISK FOR SEVERE WEATHER. THE SHOWERS/THUNDER WILL SPREAD
FURTHER E/SE ACROSS THE REMAINDER OF THE KILX CWA EARLY FRIDAY
MORNING BEFORE RAPIDLY DIMINISHING PRIOR TO MIDDAY. AFTER THAT,
A STRAY SHOWER MAY REMAIN POSSIBLE ALONG/SOUTH OF THE I-70
CORRIDOR THROUGH THE AFTERNOON...WITH DRY CONDITIONS EXPECTED
FURTHER NORTH.
*** ADDITIONAL THUNDERSTORMS FRIDAY NIGHT INTO SATURDAY ***
AFTER A LULL IN PRECIP CHANCES FRIDAY AFTERNOON AND EVENING, THE
NOCTURNAL LOW-LEVEL JET WILL ONCE AGAIN PROVIDE THE NECESSARY
FORCING FOR SCATTERED CONVECTIVE DEVELOPMENT LATE FRIDAY NIGHT.
MUCAPES WILL BE CONSIDERABLY HIGHER THAN TONIGHT IN THE
1000-1500J/KG RANGE: HOWEVER, DEEP LAYER SHEAR WILL REMAIN WEAK
AT JUST 25-35KT. AS A RESULT, THINK A FEW OF THE STRONGER CELLS
MAY BE CAPABLE OF PRODUCING GUSTY WINDS AND SMALL HAIL: HOWEVER,
THE OVERALL SEVERE RISK WILL REMAIN LOW.
AS HAS BEEN SEEN BY THE PAST FEW MODEL CYCLES, IT APPEARS A
BETTER CHANCE FOR STRONG TO POTENTIALLY SEVERE THUNDERSTORMS
WILL MATERIALIZE BY SATURDAY AFTERNOON AND EVENING AS RICHER
GULF MOISTURE ARRIVES AND A FRONTAL BOUNDARY REMAINS DRAPED
ACROSS NORTH-CENTRAL ILLINOIS. THANKS TO SURFACE DEWPOINTS
CLIMBING INTO THE MIDDLE 60S, SBCAPES WILL REACH 2000-3000J/KG
BY PEAK HEATING. THE MAIN MITIGATING FACTOR FOR WIDESPREAD
SEVERE WILL AGAIN BE THE WEAK SHEAR, WITH 0-6KM BULK SHEAR OF
ONLY 20-25KT. AREAL COVERAGE OF STORMS WILL PEAK IN THE
AFTERNOON AND EVENING AND THINK A FEW OF THE STRONGER CELLS
COULD PRODUCE MARGINALLY SEVERE WIND/HAIL. THE LATEST DAY 3
OUTLOOK FROM SPC HIGHLIGHTS ALL OF CENTRAL/SOUTHEAST ILLINOIS
WITH A MARGINAL RISK (LEVEL 1 OF 5) ACCORDINGLY.
*** CONTINUED STORMY EARLY NEXT WEEK ***
AS A SHORT-WAVE TROUGH CROSSES THE ROCKIES, DOWNSTREAM RIDGING
WILL HELP SHOVE THE FRONTAL BOUNDARY BACK NORTHWARD ON
SUNDAY...LEADING TO A VERY WARM AND DRY DAY ACROSS CENTRAL
ILLINOIS WITH HIGHS WELL INTO THE 80S. THE BIG QUESTION THEN
BECOMES HOW QUICKLY THE WESTERN TROUGH AND ITS ASSOCIATED COLD
FRONT CAN ARRIVE. THE 12Z MAY 14 MODEL SUITE HAS SLOWED THE
SYSTEM...WITH THE GFS SHOWING FROPA TUESDAY MORNING AND THE
ECMWF TUESDAY EVENING. THIS STILL LOOKS LIKE A SITUATION WHERE
SIGNIFICANT CONVECTION WILL FIRE ALONG THE FRONT WELL TO THE
WEST ACROSS MINNESOTA/IOWA/KANSAS MONDAY AFTERNOON...THEN PUSH
EASTWARD INTO AT LEAST WEST-CENTRAL ILLINOIS DURING THE EVENING.
AS A RESULT, SPC CONTINUES TO FOCUS 15-30% PROBABILITIES FOR
SEVERE ALONG/WEST OF I-55. WITH THE FRONT SLOWING, CONFIDENCE IS
GROWING THAT CONVECTION WILL RE-DEVELOP ACROSS PART OF THE CWA
ON TUESDAY AS WELL. THE LATEST DAY 6 SPC OUTLOOK SHOWS A 15-30%
CHANCE FOR SEVERE ACROSS ALL OF CENTRAL ILLINOIS ON TUESDAY, BUT
THINK THIS MAY BE A BIT TOO GENEROUS AND PREFER TO FOCUS THE
HIGHEST SEVERE CHANCES MAINLY EAST OF I-55 TUESDAY AFTERNOON AND
EVENING. STAY TUNED TO LATER FORECASTS FOR ADDITIONAL DETAILS.
ON A SIDE NOTE, WE MAY NEED TO WATCH OUT FOR BLOWING DUST ON
MONDAY AS STRONG S/SW WINDS GUSTING 30-40MPH DEVELOP WELL AHEAD
OF THE APPROACHING COLD FRONT. AFTER A BREEZY WARM DAY ON SUNDAY
TO DRY THE TOPSOIL, EVEN STRONGER WINDS MAY LOFT THE SOIL IF
SHOWERS/STORMS ARE DELAYED UNTIL EVENING.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1227 AM CDT FRI MAY 15 2026
VFR CONDITIONS ARE ANTICIPATED TO BE THE PRIMARY FLIGHT CATEGORY
ACROSS THE CENTRAL ILLINOIS TERMINALS, EXCLUDING TEMPORARY
REDUCTIONS DURING PRECIPITATION.
AS HIGH PRESSURE SHIFTS EASTWARD OVERNIGHT, SOUTHERLY FLOW WILL
ESTABLISH ITSELF OVER THE REGION. CONVECTION IS FORECAST TO
INITIATE OVER IOWA AND MISSOURI TONIGHT, TRACKING EASTWARD INTO
CENTRAL ILLINOIS BETWEEN 09Z AND 15Z. WHILE THESE SHOWERS AND
THUNDERSTORMS WILL IMPACT THE TERMINALS, THE COVERAGE IS
EXPECTED TO BECOME MORE ISOLATED AS THE MORNING PROGRESSES.
BREEZY SOUTHERLY WINDS WILL CHARACTERIZE FRIDAY'S WEATHER, WITH
SURFACE GUSTS REACHING SPEEDS OF 20-25 KTS, DIMINISHING AFTER
00Z.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...MJA
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