092
FXUS63 KDVN 182005
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
305 PM CDT FRI SEP 18 2026
KEY MESSAGES
- HEAVY RAIN AND THUNDERSTORMS ARE LIKELY FOR PORTIONS OF THE
AREA TONIGHT INTO SATURDAY MORNING AND AGAIN SATURDAY EVENING
INTO SATURDAY NIGHT. LOCALIZED FLASH FLOODING IS THE PRIMARY
CONCERN. RAPID RISES ON SMALL CREEKS AND STREAMS AND THE
FLOODING OF LOW-LYING AREAS ARE POSSIBLE.
- A FLOOD WATCH HAS BEEN ISSUED FOR PORTIONS OF EAST-CENTRAL
IOWA AND FAR NORTHWESTERN ILLINOIS FOR LATE TONIGHT THROUGH
SATURDAY EVENING. RAINFALL TOTALS OF 1-3 INCHES ARE LIKELY
(60-80%) IN THESE AREAS WITH THE POTENTIAL FOR LOCALIZED
AREAS OF 3+ INCHES.
- THERE IS A MARGINAL RISK FOR ISOLATED SEVERE STORMS FOR AREAS
SOUTH OF HIGHWAY 20 ON SATURDAY. PRIMARY SEVERE HAZARD IS
DAMAGING WINDS.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 245 PM CDT FRI SEP 18 2026
TONIGHT: ANOTHER ROUND OF HEAVY RAIN AND THUNDERSTORMS IS
EXPECTED TO DEVELOP ACROSS FAR NORTH-CENTRAL IOWA AND SOUTHERN
MINNESOTA BEFORE SHIFTING TO THE E/SE, LIKELY IMPACTING AREAS
NORTH OF I-80 LATE TONIGHT INTO EARLY SATURDAY MORNING. THIS IS
A HIGH CONFIDENCE ROUND OF HEAVY RAIN FORCED BY ISENTROPIC
UPGLIDE, LOW-LEVEL CONVERGENCE AND AN ANOMALOUSLY MOIST
ATMOSPHERE WITH NEAR RECORD PWATS (~2").
THE FLOOD WATCH, WHICH IS IN EFFECT FROM LATE TONIGHT THROUGH
SATURDAY EVENING, HAS BEEN EXPANDED FURTHER THE WEST AND
SOUTHWEST BY ROUGHLY A TIER OF COUNTIES REMAINING
NORTH/NORTHEAST OF CEDAR RAPIDS AND THE QUAD CITIES. RAINFALL
AMOUNTS BETWEEN 1-3 INCHES ARE LIKELY WITH LOCALIZED AREAS OF
3+ INCHES POSSIBLE. THE MORE WIDESPREAD RAINFALL LOOKS TO COME
IN TWO ROUNDS: 1) LATE TONIGHT INTO EARLY SATURDAY MORNING, 2)
SATURDAY EVENING INTO SATURDAY NIGHT. THERE IS A MODERATE RISK
(LEVEL 3 OF 4) FOR FLASH FLOODING NORTH OF THE I-80 CORRIDOR
ACROSS FAR EASTERN IOWA AND INTO NORTHWEST ILLINOIS, WITH A
SLIGHT RISK (LEVEL 2 OF 4) FURTHER TO THE WEST AND SOUTH. WET
ANTECEDENT CONDITIONS, WITH A WIDESPREAD 1-3"+ (LOCALLY HIGHER)
FALLING OVER THE PAST SEVERAL DAYS ALONG/NORTH OF THE HIGHWAY
30 CORRIDOR, HAS MADE THIS AREA MORE SUSCEPTIBLE TO REPEATED
ROUNDS OF HEAVY RAIN -- ESPECIALLY IN URBAN AREAS OR AROUND
STEEP TERRAIN.
CAMS CONTINUE TO HIGHLIGHT AREAS NORTH/NORTHEAST OF THE QUAD
CITIES WITH THE HIGHEST QPF AMOUNTS, GENERALLY ALIGNED WITH THE
CURRENT PLACEMENT OF THE FLOOD WATCH. THE HREF AND RRFS
ENSEMBLE PMM QPF SHOW POTENTIAL FOR 1-3" SWATHS OF RAINFALL
WITH ISOLATED POCKETS OF 3-4" FROM LATE TONIGHT THROUGH SATURDAY
NIGHT.
THERE IS ALSO A MARGINAL RISK (LEVEL 1 OF 5) FOR A FEW STRONG
TO SEVERE STORMS LATER SATURDAY AFTERNOON INTO SATURDAY NIGHT,
WITH LOCALIZED DAMAGING WINDS AS THE PRIMARY THREAT.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 245 PM CDT FRI SEP 18 2026
SUNDAY...OCCASIONAL SHOWERS AND ISOLATED STORMS ARE POSSIBLE
THROUGH THE DAY AS AN UPPER TROUGH LINGERS OVER THE REGION.
COOLER TEMPERATURES ARE ANTICIPATED WITH HIGHS IN THE 60S/70S
ACCOMPANIED BY GUSTY NORTHEAST WINDS.
SUNDAY NIGHT-TUESDAY...THE MAIN TROUGH OVER THE NORTHERN
ROCKIES FINALLY REACHES THE NORTHERN PLAINS AS LOW-TO-MID-LEVEL
RIDGING OVER SOUTH-CENTRAL CANADA CONTINUES TO PUSH THE SURFACE
TROUGH FURTHER SOUTH INTO THE LOWER OHIO RIVER VALLEY. DESPITE
THE COLD AIR ADVECTION, CVA AHEAD OF THE TROUGH KEEPS SCATTERED
LIGHT-TO-MODERATE SHOWERS (50-70% COVERAGE) AROUND SUNDAY NIGHT
INTO MONDAY. BY MONDAY NIGHT, THE TROUGH FINALLY REACHES IOWA
AS COLD-CORE SHOWERS FORM UNDERNEATH, KEEPING POPS AROUND
THROUGH TUESDAY MORNING. AS SUBSIDENCE SETS IN ON THE BACKSIDE
OF THE TROUGH AND HIGH PRESSURE BUILDS IN FROM THE NORTH, THE
OUTLOOK AREA SHOULD BE RAIN-FREE BY TUESDAY EVENING.
WEDNESDAY-THURSDAY...FALL-LIKE WEATHER IS LIKELY (70-90%) TO
RETURN FOR THE MIDDLE OF NEXT WEEK. CONFLUENCE ALOFT AND SURFACE
HIGH PRESSURE IS FORECASTED TO KEEP WEDNESDAY AND THURSDAY DRY
AS CAA KEEPS TEMPERATURES BELOW AVERAGE WITH HIGHS IN THE
MID-60S TO LOW 70S AND LOWS IN THE MID-40S TO LOW 50S.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1245 PM CDT FRI SEP 18 2026
ACTIVE WEATHER IS EXPECTED TODAY INTO SATURDAY MORNING WITH
PERIODS OF MVFR/IFR CEILINGS AND ROUNDS OF SHOWERS AND
THUNDERSTORMS. AFTER SOME IMPROVEMENT IN CEILINGS THIS
AFTERNOON/EVENING, CONDITIONS WILL DETERIORATE INTO TONIGHT WITH
MVFR/IFR LIKELY NORTH OF BRL. SCATTERED SHOWERS AND ISOLATED
STORMS ARE THEN EXPECTED LATE TONIGHT INTO SATURDAY AM, MOST
FAVORED AT DBQ AND CID. HEAVY DOWNPOURS ARE LIKELY WITH THE
STRONGEST CELLS WHICH COULD LEAD TO BRIEF VISIBILITY REDUCTIONS
UNDER 1 MILE. A RETURN TO VFR/MVFR IS ANTICIPATE BY MID/LATE
SATURDAY MORNING AS RAIN COVERAGE DECREASES ACROSS THE AREA.
DVN WATCHES/WARNINGS/ADVISORIES
IA...FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SATURDAY EVENING
FOR IAZ040>042-053-054-066.
IL...FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SATURDAY EVENING
FOR ILZ001-002-007-009.
MO...NONE.
SHORT TERM...UTTECH
LONG TERM...DELAUNE/ZU
AVIATION...UTTECH
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