594
FXUS63 KDMX 011124
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
624 AM CDT THU OCT 1 2026
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
KEY MESSAGES
- MODERATE TO HEAVY RAINFALL CONTINUES THIS MORNING. FLASH
FLOODING REMAINS POSSIBLE, AND RIVER FLOODING LIKELY.
- RAIN THIS MORNING TAPERS OFF FROM NORTHWEST TO SOUTHEAST
THROUGH THE DAY TODAY, WITH POTENTIAL FOR AN ADDITIONAL 1 TO 2
INCHES OVER SOUTHERN INTO SOUTHEASTERN IOWA THIS AFTERNOON.
- ONCE RAIN ENDS ACROSS THE AREA TODAY, COOLER, DRIER AND
BREEZIER CONDITIONS DEVELOP WITH DRY, FALL-LIKE WEATHER
THROUGH THE WEEKEND.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 216 AM CDT THU OCT 1 2026
THIS MORNING'S HEAVY RAINFALL HAS GENERALLY MOVED OUT OF THE
AREA, AND A TRAILING COLD FRONT HAS BEGUN TO PUSH SOUTHWARD.
SOME LIGHT DRIZZLE/MIST IS ACCOMPANYING THIS FRONT BUT OVERALL
SHOULD END THE RAINFALL FROM NORTHWEST TO SOUTHEAST THROUGH THE
DAY. BARRING A FEW ELEVATED SHOWERS, MUCH OF THE FORECAST AREA
SHOULD SEE RAIN ENDING BY NOON, IF NOT SOONER. BEFORE
COMPLETELY PUSHING OUT OF THE AREA THIS AFTERNOON, WE MAY SEE
SHOWERS AND EVEN A FEW STORMS FESTER ALONG THE BOUNDARY IN
SOUTHERN AND SOUTHEASTERN IOWA. THESE WILL HAVE THE POTENTIAL TO
BRING ANOTHER 1 TO 3 INCHES TO SOUTHEASTERN IOWA, ALTHOUGH IT'S
POSSIBLE THIS SECONDARY BAND ENDS UP SOUTH AND EAST OF OUR
FORECAST AREA. REGARDLESS, GIVEN THE WIDESPREAD RAIN THAT FELL
YESTERDAY AND SATURATED SOILS OVER SOUTHERN IOWA, WPC HAS
MAINTAINED A SLIGHT RISK FOR EXCESSIVE RAINFALL (LEVEL 2 OF 4)
TO ACCOUNT FOR THIS SECONDARY SWATH OF RAIN IN SOUTHEASTERN IOWA
LATER TODAY. THE FLOOD WATCH CONTINUES THROUGH THIS EVENING.
BEHIND THE COLD FRONT TODAY, CONDITIONS OVER IOWA WILL BE DRYING OUT
AND COOLER AIR FILLING IN. SLIGHTLY ENHANCED PRESSURE GRADIENTS
COMBINED WITH THE COOLER, DESCENDING AIR MASS WILL LEAD TO SOME
BREEZY POST-FRONTAL CONDITIONS TODAY. NORTHERLY WINDS OF 15 TO 20
MPH ARE EXPECTED TODAY, WITH GUSTS UP TO 30 MPH ESPECIALLY OVER
NORTHERN IOWA.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 328 PM CDT WED SEP 30 2026
THE EXTENDED FORECAST PERIOD IS EXPECTED TO MARK THE FIRST TRUE
TRANSITION TO FALL-LIKE WEATHER. BEHIND THURSDAYS COLD FRONT,
SURFACE HIGH PRESSURE WILL BUILD BACK INTO THE REGION, BRINGING
SEVERAL DAYS OF DRY WEATHER AND COOLER TEMPERATURES. PREVIOUS
FORECAST ITERATIONS DEPICTED A SHORTWAVE DIVING SOUTHEASTWARD TOWARD
THE UPPER MISSISSIPPI RIVER VALLEY, BUT THIS AFTERNOONS MODEL
GUIDANCE HAS LARGELY REMOVED THAT FEATURE, LEAVING THE AREA MOSTLY
DRY UNTIL PRECIPITATION CHANCES RETURN LATE IN THE PERIOD.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 618 AM CDT THU OCT 1 2026
THE HEAVY RAIN OVERNIGHT HAS MOSTLY MOVED OUT OF THE AREA, BUT
LINGERING LIGHT RAIN/DRIZZLE CONTINUES TO IMPACT TAF SITES THIS
MORNING. THIS IS RESULTING IN OCCASIONAL VISIBILITY REDUCTIONS,
PRIMARILY AROUND 3 TO 6 SM. CEILINGS HAVE BEGUN TO IMPROVE TO
VFR OVER NORHTERN IOWA, ALTHOUGH OCCASIONAL MVFR TO IFR CEILINGS
CONTINUE CENTRAL AND SOUTH. ADDITIONAL RAIN AND SHOWERS REMAIN
POSSIBLE THIS AFTERNOON, MOSTLY IMPACTING KDSM AND KOTM. A COLD
FRONT PASSING THROUGH THE AREA THIS MORNING IS ALSO FLIPPING
WINDS TO A NORTHERLY DIRECTION, AND WILL EVENTUALLY PRODUCE SOME
BREEZY WINDS WITH GUSTS AROUND 20 TO 25 KTS. ANY REMAINING
PRECIPITATION SHOULD DIMINISH BY LATE THIS AFTERNOON OR EARLY
EVENING, WITH CLOUDS CLEARING OUT OVERNIGHT INTO FRIDAY MORNING.
HYDROLOGY
ISSUED AT 216 AM CDT THU OCT 1 2026
ALL TYPES OF FLOODING, INCLUDING FLASH, AREAL AND RIVER, REMAIN
POSSIBLE AS ADDITIONAL MODERATE TO HEAVY RAIN FALLS ACROSS MUCH OF
THE CWA. RESPONSES ON AREA RIVERS ARE ALREADY ONGOING WITH THE
RAINFALL THAT'S FALLEN THROUGH EARLY THURSDAY MORNING, WITH
ADDITIONAL RAIN STILL ON THE WAY.
RIVER FLOOD WARNINGS HAVE BEEN ISSUED FOR LOCATIONS WHERE WE HAVE
HIGH CONFIDENCE (AT LEAST 80%) OF REACHING AT LEAST FLOOD STAGE.
A HANDFUL OF RIVER FLOOD WATCHES HAVE BEEN INTRODUCED AT RIVERS
WHERE CONFIDENCE IN FLOODING IS RELATIVELY LOWER. REFER TO THE
NATIONAL WATER PREDICTION SERVICE AT WEATHER.GOV/DESMOINES/WATER
FOR THE LATEST RIVER OBSERVATIONS AND FORECASTS.
THE RACCOON RIVER BASIN WILL LIKELY BE IMPACTED BY RAINFALL THIS
MORNING, BUT WILL SEE A MORE DELAYED RESPONSE WITH THE HEAVIEST
RAIN FALLING FARTHER NORTH (UPSTREAM) IN THE BASIN. RECENT
RAINFALL IN MUCH OF THAT BASIN HAS ALREADY PRIMED RIVERS FOR A
RESPONSE, WITH ADDITIONAL WATER FALLEN OR FALLING NOW EARLY THIS
MORNING.
FLASH FLOODING REMAINS POSSIBLE THROUGH THIS MORNING,
ESPECIALLY IN URBAN AREAS INCLUDING CREEKS AND SMALLER STREAMS.
SEASONALLY HIGH SOIL MOISTURE WILL LEAD TO FASTER AND MORE
SIGNIFICANT RUNOFF THAN NORMAL. WITH THE HEAVY RAIN THREAT
SHIFTING SLIGHTLY NORTHWARD, QUICK RESPONDING STREAMS IN THE DES
MOINES METRO (WALNUT AND FOURMILE CREEK) SEEM LESS LIKELY TO
SEE SIGNIFICANT RESPONSES, BUT IOWAY CREEK IN AMES MAY STILL
END UP UNDER THE HEAVIEST RAINFALL AND WILL BE MONITORED CLOSELY
THROUGH THE MORNING.
DMX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH LATE TONIGHT FOR IAZ024>028-033>039-
044>050-057>062-070>075-081>086-092>097.
SHORT TERM...DODSON
LONG TERM...VORST
AVIATION...DODSON
HYDROLOGY...ZOGG
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