718
FXUS63 KLOT 140834
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
334 AM CDT FRI AUG 14 2026
KEY MESSAGES
- THUNDERSTORMS WITH TORRENTIAL RAINFALL MAY CONTINUE ACROSS
AREAS SOUTHWEST OF THE CHICAGO METRO THIS MORNING.
- A LOW PRESSURE SYSTEM IS EXPECTED TO BRING SHOWERS AND
THUNDERSTORMS WITH LOCALLY TORRENTIAL RAIN AND POTENTIAL
FLOODING LATE TONIGHT INTO SATURDAY MORNING FOR PORTIONS OF
NORTHERN ILLINOIS.
- A STORMY PATTERN IS EXPECTED TO REMAIN IN PLACE THROUGH THE
WEEKEND.
DISCUSSION
ISSUED AT 334 AM CDT FRI AUG 14 2026
ONGOING SIGNIFICANT RAINFALL AND POTENTIAL FLOODING OVER FAR
SOUTHERN PORTIONS OF THE CWA SHOULD SUBSIDE SOON. HOWEVER,
CONTINUED WEAK LOW-LEVEL ISENTROPIC ASCENT COMBINED WITH
SUFFICIENT ELEVATED INSTABILITY MAY FOSTER CONTINUED DEVELOPMENT
ACROSS THE SOUTHWEST CWA THROUGH AT LEAST DAYBREAK BEFORE THE
EXISTING MODEST LLJ VEERS AND DECAYS. WILL NEED TO MONITOR IF
ANY MCV DEVELOPS WITHIN ONGOING CONVECTION OVER CENTRAL IOWA.
THIS WOULD REINVIGORATE SCATTERED CONVECTION WITH LOCALLY HEAVY
RAIN LATE THIS MORNING INTO THE AFTERNOON ACROSS, WITH THE MOST
LIKELY MCV TRACK FAVORING WESTERN PORTIONS OF THE CWA.
A ROBUST CONVECTIVE COMPLEX CURRENTLY OVER SOUTH-CENTRAL
NEBRASKA IS SIGNIFICANTLY ENHANCING A MID-LEVEL WAVE ACROSS THE
CENTRAL GREAT PLAINS. BASED ON LATEST GUIDANCE, THE VAST AMOUNT
OF CONVECTION IS EXPECTED TO TURN THIS WAVE INTO A WARM CORE LOW
THROUGH THIS MORNING. THIS WAVE/LOW WILL DRIFT ALONG A BROADER
RIDGE THROUGH TONIGHT, WITH LATEST TRAJECTORIES FAVORING A TRACK
OVER OR SLIGHTLY NORTH OF THE FORECAST AREA LATE TONIGHT INTO
SATURDAY MORNING. GIVEN HIGH-END PWAT VALUES OF 2.3" TO POSSIBLY
UPWARD OF 2.5" AND EXPECTED SLOW FORWARD MOTION OF THE WAVE,
SIGNIFICANT RAINFALL RATES OF OVER 2" PER HOUR ARE POSSIBLE NEAR
AND ALONG THE TRACK OF THE ASSOCIATED SURFACE WAVE.
ADDITIONALLY, STRONG SOUTHEAST WINDS OF ADVISORY CALIBER (AT
LEAST 45MPH) CANNOT BE RULED OUT ALONG THE SOUTHERN PERIPHERY OF
THE TRACK. A FLOOD WATCH MAY BE NEEDED FOR AREAS ROUGHLY AROUND
AND NORTH OF I-80 FOR LATE TONIGHT AND SATURDAY MORNING. WILL
ALSO NEED TO MONITOR A THREAT FOR ELEVATED CONVECTIVE LINEAR
ELEMENTS CAPABLE OF TRANSPORTING CORRIDORS OF DAMAGING WIND TO
THE SURFACE AHEAD OF THE WAVE.
ANOTHER WAVE EXPECTED TO BECOME CONVECTIVELY ENHANCED IN THE
LEE OF THE CENTRAL ROCKIES TONIGHT WILL TRACK NORTH OF THE AREA
LATE SATURDAY NIGHT, DRAGGING A COLD FRONT WITH SHOWERS ACROSS
THE CWA SOMETIME DURING THE DAYTIME HOURS ON SUNDAY.
THUNDERSTORM CHANCES WILL BE DICTATED BY THE EXPECTED TIMING OF
THE FRONT, WITH A LATER ARRIVAL IN THE AFTERNOON SUPPORTING
HIGHER COVERAGE OF STORMS AND A MARGINAL DAMAGING WIND RISK.
HIGH PRESSURE WILL BUILD SOUTHWARD OVER THE AREA EARLY NEXT
WEEK, SUPPORTING SEASONABLE TEMPERATURES AND A DECENT CHANCE OF
A DRY STRETCH MONDAY AND TUESDAY. ANOTHER STRONGER WAVE AND COLD
FRONT WILL BRING CHANCES OF SHOWERS AND STORMS ON WEDNESDAY,
WITH THE FRONT EXPECTED TO STALL WELL SOUTH OF THE AREA LATE IN
THE WEEK.
KLUBER
AVIATION /06Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 102 AM CDT FRI AUG 14 2026
KEY AVIATION FORECAST MESSAGES:
- SCATTERED SHRA AT TIMES THROUGH MID TO LATE MORNING. -SHRA MAY
LINGER BEYOND 18Z BUT THE POTENTIAL IS <30% CHANCE.
- REDUCED VSBYS TO MVFR IN BR OUTSIDE OF CHICAGO THROUGH
DAYBREAK.
- ANOTHER THUNDERSTORM COMPLEX IS LIKELY TO MOVE INTO THE AREA
LATE TONIGHT-EARLY SATURDAY MORNING.
SCATTERED SHOWERS ARE EXPECTED AT TIMES THROUGH EARLY THIS
MORNING. WHILE THE FOCUS OF GREATEST +SHRA AND TS COVERAGE
REMAINS SOUTH OF I-80, CAN'T RULE OUT A FEW LIGHTNING STRIKES
WITHIN THE AREA OF SHOWERS NEAR RFD (DID INTRODUCE A BRIEF VCTS
THERE THROUGH 7Z). THIS ACTIVITY IS DRIFTING TOWARD THE CHICAGO
METRO TERMINALS AND MAY REQUIRE A BRIEF VCTS MENTION AS WELL.
WILL MONITOR OBSERVATIONAL TRENDS CLOSELY FOR ANY SHORT FUSED
AMENDMENTS. OUTSIDE OF THE SHOWERS, HIGH LOW-LEVEL MOISTURE
CONTENT IS LEADING TO VSBY REDUCTIONS IN BR AS WELL, MAINLY
OUTSIDE OF CHICAGO TO AROUND 3-5 SM.
DID INTRODUCE A PROB30 FOR SHRA MID MORNING THROUGH EARLY
AFTERNOON TO ACCOUNT FOR WHAT IS EXPECTED TO BE A DECAYED
CONVECTIVE COMPLEX/MCV EMANATING FROM ACTIVITY DEVELOPING IN THE
NE/MO/IA BORDER AREA. WHILE THE LIGHTNING THREAT IS LOW IT IS
POSSIBLE THAT SHOWERS LINGER AS FAR EAST AS CHICAGO AND MAY BE
PAIRED WITH A PERIOD OF GUSTY SOUTHEAST WINDS (LOWER
CONFIDENCE). CAN'T FULLY RULE OUT SHOWERS AT TIMES THROUGH THE
REMAINDER OF THE DAY THOUGH THE POTENTIAL REMAINS LESS THAN 30%.
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT IN YET ANOTHER
THUNDERSTORM COMPLEX APPROACHING THE AREA LATE TONIGHT THROUGH
EARLY SATURDAY MORNING. HAVE ACCOUNTED FOR THIS WITH PREVAILING
SHRA AFTER 8Z WITH PROB30 GROUPS FOR TS AFTER 9Z TO ACCOUNT FOR
THIS POTENTIAL.
PETR
LOT WATCHES/WARNINGS/ADVISORIES
IL...FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR ILZ010-ILZ019-
ILZ021-ILZ023-ILZ032-ILZ033-ILZ039.
IN...FLOOD WATCH UNTIL 10 AM CDT /11 AM EDT/ THIS MORNING FOR
INZ010-INZ011-INZ019.
LM...NONE.
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