275
FXUS63 KILX 131743
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1243 PM CDT FRI JUN 13 2025
KEY MESSAGES
- DAILY CHANCES OF RAIN FAVOR ABOVE-NORMAL RAINFALL THROUGH THE
MIDDLE OF NEXT WEEK. THE NORMAL WEEKLY RAINFALL FOR THE MIDDLE
OF JUNE IN CENTRAL ILLINOIS IS ABOUT 1.1 INCHES.
- A WARM AND HUMID PATTERN FAVORS SLIGHTLY ABOVE-NORMAL
TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK. THE NORMAL DAILY
TEMPERATURES FOR THE MIDDLE OF JUNE IN CENTRAL ILLINOIS ARE A
HIGH OF 85 F AND A LOW OF 63 F.
- THE RISK FOR SEVERE WEATHER RETURNS TUESDAY EVENING AND EXTENDS
THROUGH AT LEAST THURSDAY.
DISCUSSION
ISSUED AT 334 AM CDT FRI JUN 13 2025
EARLY MORNING OBSERVATIONAL TRENDS EXHIBIT AN UPPER-LEVEL TROUGH
SLOWLY LIFTING ACROSS THE OZARKS, WITH LIGHT TO MODERATE RAINFALL
SPREADING INTO ILLINOIS. HI-RES GUIDANCE REMAINS IN EXCELLENT
AGREEMENT THAT PERIODS OF RAIN WILL PERSIST THROUGH MUCH OF THE
DAY AS THE UPPER TROUGH MEANDERS TOWARD US. SHOWERS MAY BECOME
MORE CONVECTIVE IN NATURE BY THIS AFTERNOON AS A MODEST LLJ VEERS
INTO SE ILLINOIS, HELPING BOOST MLCAPE VALUES OVER 1000 J/KG.
STILL, THE OVERALL SEVERE THREAT FOR TODAY WILL BE LIMITED BY LOW
SHEAR (< 30 KTS) AND POOR LAPSE RATES (< 6.5 C/KM).
THE MORE APPARENT RISK FOR TODAY IS FOR LOCALIZED URBAN FLOODING
ACROSS PORTIONS OF SOUTHEAST AND EAST-CENTRAL ILLINOIS. WHILE
FORCING FOR ASCENT IS SOMEWHAT WEAK, IT’S PERSISTENT. AND WHEN
COMBINED WITH SEASONABLY HIGH PWATS (> 95% OF MID-JUNE CLIMO); A
MOIST VERTICAL PROFILE (LOW/MID RH > 90%); A DEEP, WARM CLOUD
LAYER (> 12 KFT); AND RELATIVELY SLOW CLOUD-LAYER FLOW (20 KTS),
ANY SHOWER THAT DOES DEVELOP WILL HAVE A TENDENCY TO BE HIGHLY
EFFICIENT. THIS BECOMES EVEN MORE TRUE LATER THIS EVENING AS THE
UPPER TROUGH MOVES OVER EAST-CENTRAL ILLINOIS AND BOTH CLOUD-LAYER
WINDS AND CORFIDI UP/DOWNSHEAR VECTORS SLOW, INCREASING THE
PROSPECT FOR TRAINING OR BACKBUILDING.
THE MOST RECENT 00Z CAM GUIDANCE HINTS AT LOCALIZED RAINFALL
TOTALS EXCEEDING 2-3 INCHES THROUGH TONIGHT, BUT IN AREAS
GENERALLY NEAR AND SOUTH OF I-72/DANVILLE.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL LIKELY LINGER
(> 60% CHANCE) THROUGH SATURDAY AFTERNOON IN AREAS NEAR AND EAST
OF I-55, BEFORE THE UPPER TROUGH DEPARTS TO THE EAST BY SATURDAY
EVENING. THE SEVERE WEATHER RISK WILL REMAIN LOW, BUT WITH A
MEDIUM RISK FOR LOCALIZED URBAN FLOODING – SIMILAR TO THE PREVIOUS
DAY’S ENVIRONMENT.
A LULL IN THE PRECIP ACTIVITY IS BECOMING MORE EVIDENT SATURDAY
EVENING THROUGH MONDAY AS SHORTWAVE RIDGING BUILDS ACROSS THE
REGION, FOLLOWED BY A BRIEF BLOCKING PATTERN (SPLIT FLOW). WITH
THE SPIGOTS TURNED OFF, AND PERIODS OF SUNSHINE RETURNING SUNDAY
AND MONDAY, AFTERNOON TEMPERATURES WILL WARM INTO THE MID 80S.
OVERNIGHT LOWS WILL BE BUOYED BY SOUPY DEWPOINTS, GENERALLY
COOLING INTO THE UPPER 60S.
THE SYNOPTIC PATTERN BECOMES MORE CONDUCIVE FOR SHOWERS AND
THUNDERSTORMS FROM TUESDAY ONWARD, PARTICULARLY ACROSS THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY WHERE A MODERATELY
BUOYANT AIRMASS BUILDS BENEATH A STRENGTHENING MID-LEVEL JET CORE.
THIS INFLUX OF CAPE & SHEAR WILL INCREASE THE SPECTER OF SEVERE
WEATHER AS EARLY AS TUESDAY NIGHT ACROSS OUR NORTH, PERHAPS
BECOMING MORE WIDESPREAD WEDNESDAY OR WEDNESDAY EVENING. CERTAINLY
MORE DETAILS TO COME, ESPECIALLY AS MID-RANGE GUIDANCE BEGINS TO
BREAK DOWN THE UPPER RIDGE WITH BETTER CONSISTENCY IN COMING DAYS.
MJA
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1243 PM CDT FRI JUN 13 2025
WIDESPREAD CLOUD COVER BLANKETS CENTRAL ILLINOIS EARLY THIS
AFTERNOON COURTESY OF AN UPPER LOW SPINNING OVER MISSOURI.
SCATTERED MVFR CEILINGS HAVE BEEN NOTED FROM TIME TO TIME,
PARTICULARLY ALONG/SOUTHWEST OF A KPIA TO KDEC LINE. THINK THIS
TREND WILL CONTINUE THROUGH THE BALANCE OF THE AFTERNOON. WIDELY
SCATTERED SHOWERS ARE NOTED ON 1730Z/1230PM RADAR IMAGERY:
HOWEVER, AREAL COVERAGE WILL BECOME MORE ROBUST AS THE DAY
PROGRESSES. MOST CAMS STILL INDICATE THE POTENTIAL FOR THUNDER, SO
HAVE STUCK WITH THE PREVIOUS FORECAST FEATURING A PROB30 GROUP
FOR THUNDER BETWEEN 20Z AND 00Z. MUCH OF THE ACTIVITY WILL BE
DIURNALLY DRIVEN AND WILL FADE OUT AFTER SUNSET, BUT HAVE
MAINTAINED VCSH AT BOTH KDEC AND KCMI THROUGH THE NIGHT AS THE
UPPER LOW PIVOTS NORTHEASTWARD ALONG I-70. CEILING FORECAST IS A
BIT TRICKY AS MODELS HAVE BEEN HAVING TROUBLE DETERMINING WHEN
THEY WILL EVENTUALLY COME DOWN. LATEST RUNS OF THE RAP/HRRR
SUGGEST WIDESPREAD MVFR CEILINGS DEVELOPING THIS EVENING AND
LINGERING THROUGH 18Z SAT. IFR IS POSSIBLE, ESPECIALLY AT KDEC AND
KCMI IN CLOSER PROXIMITY TO THE LOW.
BARNES
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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