747
FXUS63 KILX 260817
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
317 AM CDT SAT JUL 26 2025
KEY MESSAGES
- A FLASH FLOOD WATCH IS IN EFFECT FOR KNOX, STARK, AND MARSHALL
COUNTIES THROUGH THIS AFTERNOON.
- A HEAT ADVISORY IS IN EFFECT ALONG AND SOUTH OF A JACKSONVILLE
TO PARIS LINE TODAY. THE OPPRESSIVE HEAT WILL SPREAD BACK
NORTHWARD ACROSS ALL OF CENTRAL ILLINOIS SUNDAY THROUGH TUESDAY
AS HEAT INDEX VALUES ONCE AGAIN REACH 105-115.
- A LOW PROBABILITY (5-15% CHANCE) OF SEVERE WEATHER EXISTS NORTH
OF THE I-70 CORRIDOR TODAY...WITH THE PRIMARY RISKS BEING
SCATTERED DAMAGING WIND GUSTS AND LARGE HAIL.
SHORT TERM
(TODAY THROUGH SUNDAY)
ISSUED AT 317 AM CDT SAT JUL 26 2025
CLUSTERS OF THUNDERSTORMS ARE ONGOING ACROSS CENTRAL ILLINOIS
EARLY THIS MORNING...WITH 0730Z/230AM RADAR SHOWING CELLS
GENERALLY ALONG A LINCOLN...TO BLOOMINGTON...TO HOOPESTON LINE.
THIS ACTIVITY WILL TRACK NORTHEASTWARD AND EXIT THE KILX CWA OVER
THE NEXT 2-3 HOURS. MEANWHILE ADDITIONAL CONVECTION DEVELOPING
UPSTREAM ACROSS NORTHERN MISSOURI WILL SPILL INTO THE NORTHERN
COUNTIES, MAINLY IMPACTING LOCATIONS ALONG AND NORTH OF A MACOMB
TO EL PASO LINE FROM 3AM TO 9AM. HEAVY RAINFALL OCCURRED ACROSS
PARTS OF THIS AREA EARLIER TODAY WITH MRMS RADAR ESTIMATES SHOWING
AMOUNTS OF 2-3 INCHES ACROSS SOUTHERN KNOX COUNTY AND AN OBSERVER
MEASURING 4 INCHES IN THE TOWN OF DELONG SOUTHEAST OF GALESBURG.
ANY ADDITIONAL RAINFALL FROM THE STORMS EXPECTED THIS MORNING WILL
OCCUR ON SATURATED SOILS AND COULD POTENTIALLY LEAD TO FLASH
FLOODING. LATEST RADAR TRENDS SUGGEST THE FIRST CLUSTER OF
SHOWERS/STORMS WILL ARRIVE ACROSS KNOX AND STARK COUNTIES OVER THE
NEXT 1-2 HOURS: HOWEVER, ADDITIONAL STORMS FURTHER W/SW MAY TRACK
A BIT FURTHER NORTH AND STAY JUST NORTH OF THE CWA AFTER SUNRISE.
NO MATTER THE EXACT TRACK OF THE LATER CONVECTION, THE RISK FOR
FLASH FLOODING IS GREAT ENOUGH TO CONTINUE THE FLASH FLOOD WATCH
FOR THE REST OF TODAY.
THE MORNING CONVECTION WILL GRADUALLY DECREASE IN AREAL COVERAGE
TOWARD MIDDAY...WITH THE EMPHASIS FOR RE-DEVELOPMENT SHIFTING
FURTHER SOUTH ACROSS THE HEART OF CENTRAL ILLINOIS BY PEAK
HEATING. WITH HREF MEAN SBCAPES OF 2500-3500J/KG AND 0-6KM SHEAR
INCREASING TO 25-30KT, THE STAGE WILL BE SET FOR A FEW STRONG TO
SEVERE CELLS CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND LARGE
HAIL. AS A RESULT, THE LATEST DAY 1 CONVECTIVE OUTLOOK FROM SPC
HIGHLIGHTS ALL LOCATIONS NORTH OF THE I-70 CORRIDOR WITH A
MARGINAL RISK (5-15% CHANCE) FOR SEVERE WEATHER. BASED ON THE
EXPECTED POSITION OF REMNANT OUTFLOW BOUNDARIES, THE GREATEST
CHANCE FOR SHOWERS AND STORMS WILL FOCUS FROM I-72 NORTHWARD.
MEANWHILE FURTHER SOUTH, LOWER RAIN CHANCES AND MORE SUNSHINE WILL
YIELD ANOTHER HOT AND HUMID SUMMER DAY WITH HEAT INDEX READINGS
PEAKING AT 100-105 ALONG/SOUTH OF A JACKSONVILLE TO PARIS LINE
WHERE THE HEAT ADVISORY REMAINS IN EFFECT.
THE UNSETTLED WEATHER WILL CONTINUE INTO SUNDAY AS A PERSISTENT
FRONTAL BOUNDARY TO THE NORTH AND OLD OUTFLOW BOUNDARIES SERVE AS
FOCUSING MECHANISMS FOR ADDITIONAL THUNDERSTORMS. THE ATMOSPHERE
WILL BECOME JUST AS UNSTABLE AS IT WILL BE TODAY: HOWEVER, DEEP-
LAYER SHEAR WILL BE WEAKER. AS A RESULT, THINK THE STORMS WILL
REMAIN SUB-SEVERE...WITH THE PRIMARY HAZARD BEING LOCALLY HEAVY
RAINFALL AND ISOLATED FLASH FLOODING. THANKS TO A SLIGHT UPTICK IN
TEMPERATURES/DEWPOINTS, HEAT INDEX READINGS WILL CLIMB TO NEAR 105
ACROSS THE BOARD. IF THESE TRENDS CONTINUE, THE HEAT ADVISORY WILL
NEED TO EXPANDED BACK NORTHWARD ACROSS ALL OF CENTRAL ILLINOIS.
BARNES
LONG TERM
(MONDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 26 2025
OPPRESSIVE HEAT AND HUMIDITY WILL PREVAIL BOTH MONDAY AND TUESDAY
AS UPPER RIDGING BUILDS OVER THE MIDWEST. HEAT INDEX VALUES WILL
REACH 105-115 BOTH DAYS...WHILE OVERNIGHT VALUES ONLY DROP INTO
THE UPPER 70S.
AS HAS BEEN NOTED BY THE PAST SEVERAL MODEL RUNS, A PATTERN
CHANGE WILL TAKE PLACE LATER NEXT WEEK AS ENERGY ROTATING AROUND A
DEEP UPPER LOW OVER HUDSON BAY SUPPRESSES THE PREVAILING RIDGE
OVER THE MIDWEST/OHIO RIVER VALLEY. THIS WILL SEND A STRONG COLD
FRONT THROUGH CENTRAL ILLINOIS ON WEDNESDAY...FOLLOWED BY MUCH
COOLER AND LESS HUMID CONDITIONS BY THE END OF THE WEEK. THE 00Z
NBM EVEN SUGGESTS A HIGH PROBABILITY (70-90% CHANCE) THAT HIGH
TEMPERATURES DROP BELOW 80 DEGREES EVERYWHERE NORTH OF THE I-70
CORRIDOR BY NEXT FRIDAY.
BARNES
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 105 AM CDT SAT JUL 26 2025
CLUSTERS OF CONVECTION CONTINUE TO LIFT NORTHEASTWARD ACROSS
CENTRAL ILLINOIS EARLY THIS MORNING...MAINLY ALONG AND JUST NORTH
OF THE I-72 CORRIDOR. BASED ON CURRENT RADAR TRENDS, HAVE
MAINTAINED THUNDER AT KSPI/KDEC THROUGH 07Z, AT KCMI THROUGH 08Z,
AND AT KBMI THROUGH 09Z. ONCE THIS ACTIVITY EXITS, ATTENTION WILL
TURN TO ADDITIONAL CONVECTION FORMING UPSTREAM N/NE OF KANSAS
CITY. THESE STORMS WILL GRADUALLY SPREAD NE OVERNIGHT AND WILL
LIKELY IMPACT NORTH-CENTRAL ILLINOIS AFTER 10Z. HAVE THEREFORE
ADDED A PROB30 FOR THUNDER AT KPIA/KBMI BETWEEN 10Z AND 14Z. AFTER
THE EARLY MORNING SHOWERS DIMINISH, SCATTERED STORMS WILL
REDEVELOP ALONG OLD OUTFLOW BOUNDARIES DURING PEAK HEATING.
PINPOINTING THIS ACTIVITY IS CHALLENGING AT THIS TIME RANGE, BUT
HAVE GENERALLY MAINTAINED PROB30 FOR THUNDER AT ALL TERMINALS FOR
THE AFTERNOON.
BARNES
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH THIS EVENING FOR ILZ027-028-030.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ049>057-061>063-
066>068-071>073.
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