614
FXUS63 KILX 071035
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
535 AM CDT TUE JUL 7 2026
KEY MESSAGES
- PLEASANT WEATHER THROUGH WEDNESDAY: DRY AND PLEASANT
CONDITIONS DOMINATE EARLY THIS WEEK WITH HIGHS IN THE MID-TO-
UPPER 80S. ONLY AN ISOLATED AFTERNOON STORM IS POSSIBLE
(20-30% CHANCE), MAINLY SOUTH OF INTERSTATE 72.
- FLASH FLOODING RISK THURSDAY AND FRIDAY: A STALLED FRONT
BRINGS A HIGH CHANCE (60-70%) FOR WIDESPREAD SHOWERS AND
STORMS. TORRENTIAL RAINFALL FROM REPEATING STORMS INTRODUCES A
RISK OF LOCALIZED FLASH FLOODING AND ISOLATED DAMAGING WINDS.
- UNCERTAIN HEAT POTENTIAL NEXT WEEK: HIGH UNCERTAINTY EXISTS
FOR MID-JULY. CENTRAL ILLINOIS WILL EITHER EXPERIENCE PERIODIC
THUNDERSTORM COMPLEXES OR A PERIOD OF DANGEROUS, EXCESSIVE
HEAT, DEPENDING ON HOW FAR EAST A BUILDING WEATHER RIDGE
TRACKS.
DISCUSSION
ISSUED AT 335 AM CDT TUE JUL 7 2026
TODAY THROUGH WEDNESDAY (SHORT-TERM QUIETER PERIOD)
A BENIGN AND RELATIVELY COMFORTABLE WEATHER PATTERN HAS
ESTABLISHED ITSELF ACROSS CENTRAL ILLINOIS. THE REGION
CURRENTLY SITS IN A TRANSITION ZONE BETWEEN A COMPACT, CUT-OFF
UPPER-LEVEL LOW SPINNING OVER SOUTHEAST MISSOURI AND A BUILDING
MID-LEVEL RIDGE SHIFTING EASTWARD THROUGH THE CORN BELT.
ALTHOUGH THE PROXIMITY OF THE UPPER LOW WARRANTS LOW-END
AFTERNOON PULSE STORM CHANCES (20-30% POPS), THE EXPANDING
INFLUENCE OF THE ADVANCING RIDGE WILL LIKELY KEEP MOST OF THE
FORECAST AREA COMPLETELY DRY TODAY. EXPECT SEASONABLY PLEASANT
CONDITIONS FOR EARLY JULY, WITH AFTERNOON HIGHS TOPPING OUT IN
THE MID-80S. COMBINED WITH DEWPOINTS HOVERING IN THE UPPER 60S
TO AROUND 70F, MAXIMUM HEAT INDEX VALUES SHOULD REMAIN CAPPED IN
THE UPPER 80S.
THIS STAGNANT, BLOCKY CONFIGURATION WILL REMAIN LARGELY IN
PLACE THROUGH WEDNESDAY AS THE UPPER LOW SLOWLY MIGRATES
EASTWARD INTO THE OHIO RIVER VALLEY. HIGH TEMPERATURES WILL
NUDGE UPWARD INTO THE UPPER 80S TO NEAR 90F AS 850 MB
TEMPERATURES WARM SLIGHTLY UNDER THE EASTWARD-SHIFTING RIDGE
AXIS. ISOLATED AFTERNOON THUNDERSTORMS (20-30% COVERAGE) REMAIN
POSSIBLE, PRIMARILY CONCENTRATED SOUTH OF THE INTERSTATE 72
CORRIDOR CLOSER TO THE DEPARTING LOW.
THURSDAY THROUGH FRIDAY NIGHT (UNSETTLED & HYDRO CONCERNS)
THE SYNOPTIC PATTERN SHIFTS DECISIVELY ON THURSDAY AS POTENT
SHORTWAVE ENERGY DIVES INTO THE UPPER MIDWEST, BREAKING DOWN THE
RIDGE AND PUSHING A WEAK COLD FRONT INTO THE REGION BY THURSDAY
NIGHT. BECAUSE THE PRIMARY UPPER-LEVEL DYNAMICS WILL QUICKLY
OUTRUN THE SURFACE BOUNDARY, THE FRONT IS PROJECTED TO BECOME
INCREASINGLY PARALLEL TO THE MID-LEVEL FLOW. THIS WILL CAUSE THE
BOUNDARY TO SHEAR OUT AND STALL DIRECTLY ACROSS CENTRAL ILLINOIS
ON FRIDAY.
THIS STALLED BOUNDARY WILL SERVE AS THE FOCAL POINT FOR ACTIVE,
UNSETTLED WEATHER DURING THE LATTER HALF OF THE WEEK, YIELDING
HIGH PROBABILITIES (60-70%) FOR WIDESPREAD RAINFALL. THE
ENVIRONMENT WILL TURN MODERATELY TO STRONGLY UNSTABLE AHEAD OF
THE FRONT, WITH MUCAPE VALUES CLIMBING INTO THE 2000-3000 J/KG
RANGE. DEEP- LAYER VERTICAL WIND SHEAR IS PROGGED TO PEAK AROUND
30 KNOTS ON THURSDAY AFTERNOON BEFORE WEAKENING INTO FRIDAY.
WHILE THE IMPROVED SHEAR PROFILES ON THURSDAY COULD SUPPORT A
FEW ORGANIZED UPDRAFTS CAPABLE OF ISOLATED SEVERE WEATHER, THE
PRIMARY CONCERN IS SHIFTING HEAVILY TOWARD LOCALIZED FLASH
FLOODING DRIVEN BY HIGHLY EFFICIENT WARM-RAIN PROCESSES.
PRECIPITABLE WATER (PWAT) VALUES ARE FORECAST TO SURGE ABOVE 2.0
INCHES, WHICH EXCEEDS THE 90TH PERCENTILE FOR JULY CLIMATOLOGY.
CONSEQUENTLY, TRAINING CONVECTIVE CELLS PRODUCING TORRENTIAL
RAINFALL RATES WILL BE THE MAIN HAZARD TO MONITOR, ALONG WITH
LOCALIZED WET DOWNBURSTS CAPABLE OF ISOLATED DAMAGING WIND
GUSTS.
SATURDAY THROUGH NEXT WEEK (EXTENDED HEAT & MCS POTENTIAL)
ONCE THE STALLED FRONT FINALLY DISSIPATES LATE IN THE WEEK, LONG-
RANGE GUIDANCE EXHIBITS EXCELLENT AGREEMENT REGARDING THE EXPANSION
OF A HIGH-AMPLITUDE SUBTROPICAL RIDGE OVER THE CENTRAL UNITED STATES.
MEDIUM-RANGE ENSEMBLES (GEFS/EPS/GEPS) CONSISTENTLY PROJECT AN
ANOMALOUS UPPER-LEVEL HIGH CENTERING NEAR THE ROCKIES DURING THE
JULY 14-17 TIMEFRAME.
SENSIBLE WEATHER ACROSS CENTRAL ILLINOIS DURING THE EXTENDED
PERIOD WILL DEPEND HEAVILY ON THE EXACT LONGITUDINAL POSITION OF
THIS RIDGE CORE. A MORE WESTERN RIDGE ORIENTATION WOULD PLACE
THE LOCAL AREA UNDER ACTIVE NORTHWEST FLOW ALOFT. THIS WOULD
OPEN THE DOOR FOR PERIODIC, RIDGE-RIDING MESOSCALE CONVECTIVE
SYSTEMS (MCSS) THAT WOULD TEMPER AFTERNOON TEMPERATURES VIA
PERSISTENT CLOUD COVER AND CONVECTIVE DEBRIS. CONVERSELY, IF THE
RIDGE CORE MIGRATES FURTHER EASTWARD DIRECTLY INTO THE CORN
BELT, A SPELL OF DANGEROUS, EXCESSIVE HEAT COULD RAPIDLY DEVELOP
BY MID-JULY.
GIVEN THE TYPICAL MODEL VARIANCE AT THIS TIME RANGE, TRENDS
WILL BE MONITORED CLOSELY OVER THE COMING FORECAST CYCLES.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 530 AM CDT TUE JUL 7 2026
VFR CONDITIONS WILL PREVAIL THROUGH THIS TAF PERIOD AS ELONGATED
SURFACE HIGH PRESSURE STRETCHES FROM THE GREAT LAKES TO THE CORN
BELT. SOME ISOLATED SHOWERS OR THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON, BUT CONFIDENCE AND COVERAGE REMAIN TOO LOW TO INCLUDE
A PROB30 MENTION IN THE TAFS AT THIS TIME. WINDS WILL PRIMARILY
BE FROM THE NORTH OR NORTHEAST BETWEEN 3-7 KTS THROUGH THE
PERIOD.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...37/MJA
DISCUSSION...37/MJA
AVIATION...MJA
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