801
FXUS63 KDVN 111708
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1208 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
SEVERE STORMS WILL 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.
UPDATE
ISSUED AT 824 AM CDT FRI SEP 11 2026
THE DENSE FOG AREA HAS CONTINUED TO MOVE NORTHWEST THIS MORNING,
AND REMAINED COMPLETELY DENSE THROUGH 8 AM. IT IS STILL MOVING
NORTHWEST, BUT BEGINNING TO SHOW SIGNS OF LIFTING/DISSIPATING ON
IT'S EAST EDGE AS OF 830 AM, AND SOME GENUINE HOLES HAVE
DEVELOPED IN SOUTHEAST IOWA. THESE TRENDS ARE CHALLENGING, BUT
THE 9 AM EXPIRATION STILL LOOKS GOOD IN MOST AREAS. I WILL MOST
LIKELY EXPIRE THE ADVISORY, BUT KEEP AN SPS GOING THROUGH 1030
AM FOR PATCHY DENSE/ POCKETS OF SLOWER IMPROVEMENT OF THE DENSE
FOG.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 248 AM CDT FRI SEP 11 2026
AREAS OF FOG HAVE DEVELOPED EARLY THIS MORNING, PRIMARILY ALONG
RIVER VALLEYS IN WEST-CENTRAL ILLINOIS AND NORTHEAST MISSOURI. THIS
FOG IS EXPECTED TO BECOME MORE WIDESPREAD THROUGH THE EARLY MORNING
HOURS AND EXPAND AS FAR NORTH AS THE HIGHWAY 34 CORRIDOR. SOME
POCKETS OF DENSE FOG WILL BE POSSIBLE, PARTICULARLY IN OUR
SOUTHERNMOST TIER OF COUNTIES. AS SUCH, A DENSE FOG ADVISORY IS IN
EFFECT FOR PARTS OF NORTHEAST MISSOURI, SOUTHEAST IOWA, AND WEST-
CENTRAL ILLINOIS THROUGH 9 AM THIS MORNING.
AFTER THE FOG BURNS OFF THIS MORNING, A PLEASANT AND MOSTLY CLEAR DAY
IS IN STORE AS WE REMAIN UNDER HIGH PRESSURE. CLEAR SKIES WITH POCKETS
OF DIURNALLY-DRIVEN CLOUDS ACROSS NORTHWEST ILLINOIS WILL ALLOW FOR
HIGHS IN THE UPPER 70S TO LOW 80S. OVERNIGHT, INCREASING MOISTURE
ADVECTION TO OUR WEST WILL SUPPORT THE DEVELOPMENT OF SHOWERS AND
STORMS ALONG A BOUNDARY STRETCHING FROM NORTHERN WISCONSIN TO
CENTRAL IOWA, THOUGH THERE IS SOME UNCERTAINTY ON THE SOUTHERN
EXTENT. IF THESE SHOWERS AND ISOLATED STORMS DO DEVELOP IN CENTRAL
IOWA, THEY ARE EXPECTED TO REACH EASTERN IOWA EARLY SATURDAY MORNING
IN A DECAYING MODE. AS SUCH, LOW POPS HAVE BEEN CONTINUED THROUGH
SATURDAY MORNING ACROSS OUR NORTHWEST, BUT MUCH OF THE AREA WILL
REMAIN DRY.
WAA WILL CONTINUE THROUGH THE DAY SATURDAY, LEADING TO INCREASING
TEMPERATURES AND DEWPOINTS. HIGHS FROM THE UPPER 70S TO THE MID 80S
ARE POSSIBLE, THOUGH AREAS OF CLOUDS COULD HELP TEMPER HIGHS,
ESPECIALLY IN OUR NORTHWESTERN COUNTIES. A MODEST POOL OF
INSTABILITY IS EXPECTED TO DEVELOP OVER MUCH OF THE AREA, WHICH WILL
SUPPORT THE POTENTIAL FOR ISOLATED SHOWERS AND STORMS IN THE EVENING
HOURS. WITH THE BEST VERTICAL SHEAR DISPLACED TO OUR WEST AND
SOUTHWEST, THE POTENTIAL FOR ANY SEVERE THUNDERSTORMS IS LOW, THOUGH
AN ISOLATED STRONG STORM COULD BE POSSIBLE IN NORTHEAST
MISSOURI.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 248 AM CDT FRI SEP 11 2026
AS SATURDAY'S SYSTEM DEPARTS, MID-LEVEL RIDGING WILL BUILD IN AHEAD
OF AN APPROACHING SHORTWAVE. THIS WILL LEAVE US ON THE EASTERN EDGE
OF HIGH PRESSURE OVER THE NORTHERN PLAINS, SANDWICHED BETWEEN COOL,
DRY AIR TO OUR NORTH AND WARM, MOIST AIR TO OUR SOUTH. THIS SETUP,
COMBINED WITH ZONAL TO SOUTHWESTERLY FLOW ALOFT, WILL BRING US DAILY
CHANCES FOR SHOWERS AND STORMS THROUGH MUCH OF THE COMING WEEK.
OF PARTICULAR NOTE IN THIS ACTIVE PERIOD IS THE AFOREMENTIONED
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.
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.
UPDATE...ERVIN
SHORT TERM...ELLINGWORTH
LONG TERM...ELLINGWORTH
AVIATION...ERVIN
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