654
FXUS63 KDVN 200543
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1243 AM CDT THU AUG 20 2026
KEY MESSAGES
- ISOLATED TO SCATTERED (30-50%) CONVECTION IS EXPECTED TO
CONTINUE ACROSS WEST-CENTRAL ILLINOIS INTO THE EVENING. A FEW
STORMS MAY BE STRONG TO SEVERE.
- MORE FOG IS EXPECTED LATE TONIGHT INTO THURSDAY MORNING DUE TO
LIGHT WINDS AND HIGH MOISTURE LEVELS IN THE ATMOSPHERE.
- OUTSIDE OF ANOTHER CHANCE OF RAIN WITH A FRONT LATE THURSDAY
NIGHT INTO FRIDAY NIGHT, RAIN CHANCES LOOK VERY LIMITED INTO
NEXT WEEK.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 140 PM CDT WED AUG 19 2026
CONVECTION HAS INITIATED SOUTH OF I-80 AHEAD OF THE SLOWLY ADVANCING
COOL FRONT. THE CONVERGENCE ALONG THE FRONT IS WEAK AS IS THE
OVERALL FORCING. THUS THE CONVECTION SHOULD RAPIDLY DISSIPATE WITH
SUNSET.
UNTIL THE SUN SETS, MID-LEVEL LAPSE RATES ARE RESPECTABLE WITH SHEAR
SLOW INCREASING FROM AN UPPER LEVEL JET STREAK AND AN APPROACHING
CONVECTIVELY INDUCED VORT MAX. WHILE THE PROBABILITY IS LOW (<25%)
AN ISOLATED STRONG TO SEVERE STORM CANNOT BE RULED OUT.
LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE WITH ANY STORM WHICH
MAY RESULT IN PONDING OF WATER OR AT WORST A LOW END LOCALIZED FLASH
FLOOD.
LATE TONIGHT INTO THURSDAY MORNING, PATCHY IF NOT AREAS OF FOG ARE
EXPECTED TO DEVELOP DUE TO THE LIGHT WINDS. LOCALLY DENSE FOG IS
POSSIBLE AROUND OR SHORTLY AFTER SUNRISE WHICH MAY DROP VISIBILITIES
UNDER ONE HALF MILE IN SPOTS.
ONCE THE FOG BURNS OFF AROUND MID-MORNING THURSDAY, TEMPERATURES
NEAR NORMAL WITH SLIGHTLY LOWER HUMIDITY LEVELS WILL BE SEEN.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 140 PM CDT WED AUG 19 2026
THURSDAY NIGHT THROUGH WEDNESDAY
ASSESSMENT...LOW (20-30%) CONFIDENCE ON LATE WEEK RAIN CHANCES
THE MODEL CONSENSUS CONTINUES TO POINT TO LATE THURSDAY NIGHT INTO
FRIDAY EVENING FOR ANOTHER, ALBEIT LOW, CHANCE OF RAIN WITH THE
PASSAGE OF ANOTHER FRONT. GIVEN WHAT HAS HAPPENED WITH THE PREVIOUS
FRONT, I WOULD NOT BE SURPRISED IF THE 20-40% CHANCES FOR RAIN ARE
DELAYED UNTIL THE FRIDAY/FRIDAY NIGHT TIME PERIOD.
AS MENTIONED YESTERDAY, NORTHWEST FLOW ALOFT MEANS THAT ANY
DISTURBANCE MOVING THROUGH WILL BE MOISTURE STARVED. THUS THE
PROSPECTS FOR ANY RAIN OUTSIDE OF THE MORE LIKELY FRIDAY/FRIDAY
NIGHT TIME PERIOD IS VERY LIMITED.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1236 AM CDT THU AUG 20 2026
VFR CONDITIONS WILL PREVAIL THROUGH MUCH OF THE TAF PERIOD, WITH
LIGHT AND VARIABLE WINDS. BETWEEN 09-15Z, WE WILL SEE THE
POTENTIAL FOR FOG DEVELOPMENT. BEST CHANCES WILL BE IN OUR
SOUTH, WHERE A SLOW MOVING BOUNDARY REMAINS. ALTHOUGH, NORTHERN
AREAS HAVE ALSO CLEARED OUT AND PATCHY DENSE FOG CANNOT BE RULED
OUT THERE EITHER AS HIGH PRESSURE APPROACHES, ESPECIALLY IN
RIVER VALLEYS. OPTED TO LARGELY MESSAGE FOG POTENTIAL WITH
TEMPO GROUPS AT THIS TIME. OTHERWISE, LIGHT/VARIABLE WINDS AND A
MIX OF CLOUDS/SUN WILL REMAIN AFTER 15Z TODAY.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...GUNKEL
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