594
FXUS63 KDVN 111852
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
152 PM CDT FRI SEP 11 2026
KEY MESSAGES
- LOW CHANCES (10-25%) FOR SHOWERS AND STORMS EARLY SATURDAY
MORNING, WITH ADDITIONAL STORMS POSSIBLE SATURDAY AFTERNOON.
ISOLATED STRONG STORMS MAY BE POSSIBLE IN NORTHEAST MISSOURI
DURING THE AFTERNOON.
- AN ACTIVE PATTERN WITH DAILY CHANCES FOR SHOWERS AND STORMS IS
IN STORE FOR THE UPCOMING WEEK. SEVERE POTENTIAL IS HIGHEST
FOR STORMS ON MONDAY. DUE TO THIS, SPC HAS ISSUED A SLIGHT,
LEVEL 2 OF 5, RISK FOR SEVERE STORMS ON MONDAY.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 152 PM CDT FRI SEP 11 2026
WHILE TEMPERATURES HAVE NOT FELT MUCH LIKE FALL IS OF YET, THIS
MORNING'S FOG EVENT SURE LOOKED LIKE IT! LATE NIGHT FOG
DEVELOPMENT IN OUR SOUTHERN COUNTIES ADVECTED AND SPREAD NORTHWEST
TO REACH NEARLY UP TO IOWA CITY AND CEDAR RAPIDS BEFORE DISSIPATION
WON OUT BY 10 AM. BY LATE MORNING, WITH SOUTHERLY WINDS REMAINING
UNDER 12 KTS. THIS IS CERTAINLY A PROBLEM MORE ASSOCIATED WITH
COOL SEASON LONG NIGHTS AND LONG LASTING MORNING INVERSIONS. ANYHOW,
THE FOG HAS NOW LIFTED INTO A SHALLOW CUMULUS/STRATUS FIELD OVER FAR
EASTERN IOWA AND FAR WESTERN ILLINOIS. THIS SHOULD GRADUALLY
DISSIPATE THE REST OF THE AFTERNOON, WITH SUNSHINE LASTING THROUGH
SUNSET, ALONG WITH PLEASANT TEMPERATURES IN THE LOWER 80S, AND
MODERATE HUMIDITY.
TONIGHT, INITIALLY CLEAR SKIES WILL BEGIN TO CLOUD UP FROM WEST TO
EAST OVERNIGHT, AS WAA BEGINS ALOFT. MOST GUIDANCE IS DRY FOR
TONIGHT, BUT THERE IS ENOUGH SIGNAL FOR A FEW SHOWERS AND
THUNDERSTORMS IN OUR WESTERN COUNTIES AFTER MIDNIGHT TO KEEP THE 20%
POPS GOING, ALONG WITH SPOTTY LIGHT QPF. THIS ACTIVITY, SHOULD IT
OCCUR, WILL LINGER INTO SATURDAY MORNING, MAINLY SOUTH OF HIGHWAY 34
IN SOUTHEAST IA, AND NORTHEAST MO. NO SEVERE WEATHER OR STRONG STORM
THREATS ARE EXPECTED.
SATURDAY REMAINS A MAINLY DRY DAY FOR OUR REGION, WITH THE
BAROCLINIC ZONE ALOFT MAINLY SOUTHWEST OF OUR CWA. SOME ISOLATED
SHOWERS/STORMS ARE POSSIBLE IN OUR FAR SOUTHWESTERN COUNTIES NEAR
THAT ELEVATED BOUNDARY SOUTH OF US, BUT THE MAJORITY OF OUR COUNTIES
ARE EXPECTED TO REMAIN DRY THROUGH SATURDAY EVENING. POPS IN THE
SOUTH ARE ONLY 10-20% FOR THIS LOW CHANCE.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 152 PM CDT FRI SEP 11 2026
BY SUNDAY, THERE IS BROAD SUPPORT FOR SHIFTING THE SURFACE AND
ELEVATED BOUNDARIES FOCUSING THE STORMS, MUCH CLOSER TO OUR CWA.
THIS WILL BEGIN A LONG DURATION OF RAIN AND THUNDERSTORMS NEAR OUR
LATITUDE. INITIALLY, INSTABILITY IS QUESTIONABLE THOUGH SUNDAY,
WITH THE MAIN BOUNDARY STILL SOUTHWEST OF EASTERN IOWA. THIS
SEEMS TO BE REFLECTED IN 40-70 PERCENT POPS, BY SUNDAY AFTERNOON
AND EVENING, WITH RELATIVELY LIGHT QPF UNDER 0.20".
OF PARTICULAR NOTE IN THIS ACTIVE PERIOD IS THE MONDAY SHORTWAVE.
LATEST GUIDANCE HAS THIS WAVE TRENDING SLOWER, RESULTING IN THE
INITIAL WARM FRONT NOT REACHING THE AREA UNTIL MONDAY
AFTERNOON. THIS HAS LEAD TO A DECREASING TREND IN HIGH
TEMPERATURES FOR MONDAY, THOUGH HIGHS ARE STILL EXPECTED TO BE
ABOVE-NORMAL DUE TO THE STRONG WARM ADVECTION REGIME. THIS WILL
ALSO ESTABLISH INSTABILITY ACROSS THE WARM SECTOR SUPPORTIVE OF
SHOWERS AND THUNDERSTORMS. GUIDANCE ALSO SUGGESTS THAT VERTICAL
SHEAR WILL BE NEAR 40-50 KTS AND THUS ALLOW FOR ORGANIZED
CONVECTION. THIS IS MOST LIKELY WITH FORCING ALONG A DESCENDING
COLD FRONT, THOUGH UNCERTAINTY WITH TIMING MAKES IT UNCLEAR
WHETHER THIS THREAT WOULD BE IN THE DAYTIME OR OVERNIGHT HOURS.
AS THIS FRONTAL BOUNDARY PASSES THROUGH THE AREA, IT IS EXPECTED TO
STALL ACROSS THE REGION. WHILE THERE IS SOME UNCERTAINTY IN WHERE
EXACTLY THIS BOUNDARY WILL SET UP, CURRENT GUIDANCE SUGGESTS IT WILL
BE ALONG OUR SOUTH. THIS THEN PROVIDES THE FOCUS FOR RAINFALL OVER
THE NEXT SEVERAL DAYS, ESPECIALLY AS SOUTHWESTERLY FLOW PROVIDES A
CONTINUOUS STREAM OF MOISTURE. ADDITIONAL WAVES TOWARDS THE LATTER
HALF OF THE PERIOD WILL HELP PUSH THIS BOUNDARY OUT OF THE REGION,
THOUGH CHANCES FOR RAIN WILL REMAIN. THE NEAR DAILY RAINFALL
POTENTIAL, OFFERS A GROWING THREAT FOR HEAVY RAINFALL, AND A
RATHER WIDESPREAD CHANCE FOR 2-4 INCHES IS GROWING IN THE
REGION. IF THIS SETS UP OVER RECENT WET COUNTIES, A FLOOD THREAT
COULD DEVELOP.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1206 PM CDT FRI SEP 11 2026
VISIBILITIES HAVE IMPROVED LATE THIS MORNING, AND MOST CIGS ARE
NOW VFR. WE HAVE CONTINUED TO USE NOWCASTING TOOLS TO ATTEMPT
CLEARING TRENDS. CONDITIONS TO IMPROVE OR REMAIN VFR AT ALL
SITES THROUGH TONIGHT AS STRONGER SOUTHERLY FLOW IS ESTABLISHED
AHEAD OF A COLD FRONT, SWITCHING WINDS TO NORTHWEST AROUND
17-19Z SATURDAY
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...ERVIN
LONG TERM...ELLINGWORTH/ERVIN
AVIATION...ERVIN
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