633
FXUS63 KILX 300854
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
354 AM CDT WED JUL 30 2025
KEY MESSAGES
- PATCHY DENSE FOG WILL LINGER UNTIL SHORTLY AFTER SUNRISE.
- A HEAT ADVISORY REMAINS IN EFFECT TODAY FOR LOCATIONS ALONG AND
SOUTH OF A TAYLORVILLE TO PARIS LINE WHERE HEAT INDEX VALUES
WILL ONCE AGAIN PEAK AT 100-105 DEGREES THIS AFTERNOON.
- A COUPLE ROUNDS OF THUNDERSTORMS WILL IMPACT CENTRAL ILLINOIS
THROUGH THIS EVENING. THERE IS A LOW PROBABILITY (5-15% CHANCE)
THAT A FEW OF THE CELLS WILL PRODUCE DAMAGING WIND GUSTS.
- DUE TO COPIOUS ATMOSPHERIC MOISTURE AND WET SOIL CONDITIONS, A
FLOOD WATCH IS IN EFFECT FOR LOCATIONS ALONG AND NORTHWEST OF A
RUSHVILLE TO CLINTON LINE THROUGH TONIGHT.
DISCUSSION
ISSUED AT 354 AM CDT WED JUL 30 2025
..PATCHY DENSE FOG EARLY THIS MORNING
BOUNDARY LAYER MOISTURE REMAINS ABUNDANT ACROSS CENTRAL ILLINOIS
EARLY THIS MORNING AS EVIDENCED BY 08Z/3AM SURFACE DEWPOINTS IN
THE LOWER TO MIDDLE 70S. THANKS TO CLEAR SKIES AND NEARLY CALM
WINDS, FOG HAS DEVELOPED...WITH A FEW SPOTS OCCASIONALLY DIPPING
TO LESS THAN 1 MILE VISIBILITY. CAMS SUGGEST VISBYS WILL SLOWLY
DECREASE OVER THE NEXT COUPLE OF HOURS, BUT DO NOT INDICATE
WIDESPREAD DENSE FOG. IR SATELLITE IMAGERY IS SHOWING CONVECTIVE
DEBRIS SPILLING INTO THE AREA FROM THE NORTHWEST, SO A HIGH
OVERCAST WILL DEVELOP AND LIKELY PREVENT VISBYS FROM COMPLETELY
TANKING. WILL ADD PATCHY DENSE FOG WORDING TO THE FORECAST AND
HIGHLIGHT WITH A SPECIAL WEATHER STATEMENT.
..HEAT ADVISORY ACROSS SOUTH-CENTRAL ILLINOIS TODAY
ONE MORE DAY OF OPPRESSIVE HEAT AND HUMIDITY WILL OCCUR: HOWEVER,
THE HIGHEST HEAT INDEX READINGS WILL BE CONFINED TO LOCATIONS
ALONG AND SOUTH OF A TAYLORVILLE TO PARIS LINE DUE TO INCREASED
CLOUD COVER AND RAIN CHANCES FURTHER NORTH. WITH HIGH TEMPERATURES
REACHING THE LOWER TO MIDDLE 90S AND HEAT INDEX VALUES PEAKING AT
100-105 DEGREES, THE HEAT ADVISORY FOR THE SE KILX CWA WILL REMAIN
IN EFFECT UNTIL 7PM.
..MARGINAL RISK FOR SEVERE WEATHER THROUGH TONIGHT
CLUSTERS OF THUNDERSTORMS HAVE DEVELOPED NEAR A STATIONARY FRONTAL
BOUNDARY ON THE NOSE OF A 30KT 850MB JET ACROSS EASTERN NEBRASKA
INTO WESTERN/CENTRAL IOWA EARLY THIS MORNING. ONE OF THE CLUSTERS
HAS ORGANIZED INTO A LINE FROM DES MOINES TO JUST NORTH OF THE
KANSAS CITY METRO. WHILE THE STORMS WILL GENERALLY WEAKEN AS THEY
TRACK FURTHER EASTWARD AWAY FROM THE JET, RADAR TIMING TOOLS SHOW
THEM SPILLING INTO THE ILLINOIS RIVER VALLEY BETWEEN 8AM AND 10AM.
SEVERE WEATHER IS NOT EXPECTED: HOWEVER, ABUNDANT LIGHTNING AND
LOCALLY HEAVY DOWNPOURS WILL BE LIKELY.
THE INITIAL LINE OF CONVECTION WILL DIURNALLY WEAKEN AS IT ENTERS
THE WESTERN CWA, BUT MAY RE-INVIGORATE FURTHER EAST ALONG THE I-55
CORRIDOR BY MIDDAY AS HREF SBCAPES PEAK AT 2500-3000J/KG. AS A
SHORT-WAVE TROUGH APPROACHES FROM THE NORTHWEST, DEEP-LAYER SHEAR
WILL INCREASE...WITH NAM 0-6KM BULK SHEAR VALUES REACHING 25-35KT.
THINK THE COMBINATION OF MODERATELY STRONG INSTABILITY AND DECENT
SHEAR WILL BE ENOUGH TO SUPPORT SOME STORM ORGANIZATION...LEADING
TO AT LEAST A LOW RISK FOR SCATTERED DAMAGING WIND GUSTS. LATEST
OUTLOOK FROM SPC HIGHLIGHTS ALL OF CENTRAL ILLINOIS WITH A
MARGINAL RISK FOR SEVERE, BUT WOULD NOT BE SURPRISED IF THIS IS
UPGRADED TO A SLIGHT RISK LATER THIS MORNING. ONCE THE INITIAL
LINE PASSES AND/OR DISSIPATES THIS AFTERNOON, ADDITIONAL CELLS MAY
FORM ALONG RESIDUAL OUTFLOW BOUNDARIES OR A SLOWLY-MOVING COLD
FRONT DROPPING SOUTHEASTWARD OUT OF IOWA. THE END RESULT MAY BE
ANOTHER ROUND OF THUNDERSTORMS THIS EVENING. ANY SEVERE RISK WILL
BE REALIZED DURING THE EVENING, WITH LINGERING CONVECTION
WEAKENING OVERNIGHT AS INSTABILITY WANES.
..FLOOD WATCH THROUGH TONIGHT
AS STATED ABOVE, A COUPLE ROUNDS OF THUNDERSTORMS ARE ANTICIPATED
TODAY AND TONIGHT. MIDWEST REGIONAL CLIMATE CENTER (MRCC) ANALYSIS
SHOWS MOST LOCATIONS ALONG/NORTH OF A RUSHVILLE TO CLINTON LINE
HAVE RECEIVED 200-500% OF THEIR MEAN PRECIP OVER THE PAST 7 DAYS.
IN ADDITION, THE LATEST RFC GUIDANCE INDICATES 6-HOUR FLASH FLOOD
CRITERIA OF JUST 1.50 TO 2 INCHES ACROSS THIS AREA. GIVEN
PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES, HAVE OPTED TO
ISSUE A FLOOD WATCH THROUGH TONIGHT. THINK THE PRIMARY RISKS WILL
OCCUR WHEN STRONGER STORMS DEVELOP OVER URBAN AREAS OR WHEN ONE OR
MORE STORMS IMPACT LOW-LYING FLOOD-PRONE LOCATIONS.
BARNES
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1226 AM CDT WED JUL 30 2025
LIGHT WINDS UNDER AN EXITING SURFACE RIDGE OF HIGH PRESSURE MAY
RESULT IN PATCHY MVFR FOG THIS MORNING. HOWEVER, THICKER CIRRUS FROM
THUNDERSTORM ANVILS OFF TO OUR WEST/NORTHWEST SHOULD LIMIT THIS,
ESPECIALLY AT WESTERN AIRFIELDS. A CHALLENGING FORECAST LIES
AHEAD WITH SEVERAL ROUNDS OF SHOWERS/STORMS POSSIBLE OVER THE NEXT
24 HOURS. THE FIRST LOOKS TO ARRIVE BY MID TO LATE MORNING AS IT
SPREADS ACROSS THE AREA THROUGH EARLY AFTERNOON. BEYOND THAT
PROB30 GROUPS CONTINUE TO HANDLE ADDITIONAL CHANCES DUE TO VERY
LOW CONFIDENCE. WIND DIRECTIONS WILL MOVE AROUND A LOT TODAY, BUT
SPEEDS SHOULD REMAIN LIGHT ASIDE FROM CONVECTIVELY ENHANCED WINDS.
NMA
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM 7 AM CDT THIS MORNING THROUGH THURSDAY MORNING
FOR ILZ027>030-036.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ052-054>057-
061>063-066>068-071>073.
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