672
FXUS63 KDMX 271740
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1240 PM CDT SUN SEP 27 2026
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- OVERCAST SKIES TODAY WITH LINGERING DRIZZLE THROUGH THE MID
AFTERNOON, MAINLY NORTH AND EAST. HIGHS IN THE UPPER 60S.
- DRY AND MILD WEATHER MONDAY WITH HIGHS IN THE LOWER 70S.
- HIGH CONFIDENCE IN WIDESPREAD AND REPEATED RAIN CHANCES BY MID
NEXT WEEK, WITH RENEWED FLOODING CONCERNS AND A FEW
THUNDERSTORMS.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 133 AM CDT SUN SEP 27 2026
HIGH MOISTURE CONTENT WAFTED IN THE AIR OVER IOWA OVERNIGHT.
THE 00Z OAX SOUNDING HAD PWATS WITHIN A TENTH OF AN INCH OF THE
DAILY MAX FOR THE DAY. STEADY RAIN CIRCULATED AROUND AN MCV IN
SOUTHERN IOWA AND SHOWERS AND A FEW STORMS. DRIZZLE WAS COMMON
BENEATH THE STRATUS IN NORTHWEST IOWA. TRENDED HIGHS LOWER TODAY AS
CLOUDS AND DRIZZLE WILL DELAY THEIR DEPARTURE UNTIL THE AFTERNOON.
EXTENDED PRECIP MENTIONS UNTIL AROUND 20Z IN THE NORTH AND EAST.
THIS IS WHERE DEEP SATURATION HANGS ON THE LONGEST. SHEAR AND LIFT
ARE NEGLIGIBLE DURING THE DAY, BUT ITS HARD TO DISCOUNT NEAR
SATURATION UP TO 400MB IN THE SOUNDINGS AND LOW-LEVEL CONDENSATION
PRESSURE DEFICITS BELOW 10MB. HIGH PRESSURE WILL CHEW AWAY AT
THE MOISTURE IN THE EAST IN THE AFTERNOON, BUT THE EASTERLY FLOW
WILL KEEP STRATUS IN PLAY INTO MONDAY. RAIN CHANCES WILL PAUSE
UNTIL TUESDAY. WESTERN IOWA WILL HANG ONTO LOW-LEVEL SATURATION
WHICH WILL ALLOW FOR FOG DEVELOPMENT SUNDAY NIGHT INTO MONDAY
MORNING, AIDED BY LIGHT WINDS UNDER 5KTS. ENOUGH DRY AIR MAY
TRIUMPH IN SOUTHEAST IOWA TO ALLOW FOR SOME SUNSHINE IN THE
AFTERNOON, OTHERWISE THE REST OF THE STATE WILL BE MOSTLY
CLOUDY.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 258 PM CDT SAT SEP 26 2026
THE DRY WEATHER IS SHORT LIVED, AS TUESDAY LOOKS LIKE THE FIRST OF
SEVERAL MORE RAINY DAYS WITH RENEWED FLOODING POTENTIAL. BY TUESDAY,
THE WESTERN TROUGH IS CUTOFF FROM THE MAIN FLOW AND SLOWLY MAKES ITS
WAY TOWARDS IOWA, LEAVING THE AREA SITTING BENEATH SEVERAL DAYS OF
SOUTHWEST FLOW. PARTICULARLY ON TUESDAY AND WEDNESDAY AND PERHAPS
THURSDAY, A SLOW MOVING SURFACE BOUNDARY LOOKS TO SET UP SW TO NE
OVER IOWA WITH REPEATED FLARE UPS OF THE LLJ AND A PERSISTENT
MOISTURE PLUME WITH PWATS OF 1.5-2". THE WILD CARD IN ALL THIS IS
THE BEHAVIOR OF HURRICANE POLO, WHOSE REMNANTS AT MID LEVELS MAY
MAKE IT PAST THE SIERRA MADRE MOUNTAINS IN MEXICO AND HELP TO
ENHANCE THE GULF MOISTURE TRANSPORT AHEAD OF THE CUTOFF LOW. THE
RESULT IS HIGH CONFIDENCE IN REPEATED ROUNDS OF HEAVY RAINFALL AND A
FEW THUNDERSTORMS MID WEEK. WPC QPF GUIDANCE SHOWS WIDESPREAD 48HR
TOTALS NEAR 2-4", AND THE THREAT FOR LOCALIZED HIGHER TOTALS DUE TO
TRAINING THUNDERSTORMS IS DEFINITELY PRESENT. GIVEN ALREADY HIGH
SOIL MOISTURE CONTENT, EXPECTED TOTALS WILL BE ENOUGH TO BRING UP
FLASH FLOOD AND RIVER FLOOD THREATS. EXPERIMENTAL HEFS GUIDANCE HAS
A 50% CHANCE THAT MANY CENTRAL AND SOUTHERN IOWA RIVERS AND STREAMS
REACH OR EXCEED ACTION STAGE AND BORDER ON MINOR FLOOD STAGE NEXT
WEEK, AND A 30% CHANCE THAT SOME (RACCOON/SKUNK/THOMPSON) REACH
MINOR TO MODERATE. WITH SO MANY MOVING PIECES ON THE SYNOPTIC AND
MESOSCALE, TRENDS WILL NEED TO BE MONITORED AND CHANGES ARE
EXPECTED.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1240 PM CDT SUN SEP 27 2026
IFR AND LIFR STRATUS CLOUDS HAVE BEEN PERSISTING THIS MORNING
AND GENERAL TREND THROUGH THE PERIOD IS TO HOLD ONTO
RESTRICTIONS LONGER THAN PREVIOUS FORECAST. OTHERWISE, THE
SPOTTY SHOWERS AND LIGHT DRIZZLE HAVE BEEN SLOWLY WANING THIS
MORNING. HAVE FURTHER LOWERED VISIBILITY RESTRICTIONS INTO IFR
TONIGHT AT FOD/MCW/ALO DUE TO FOG. CEILINGS MAY IMPROVE QUICKER
TOWARD OR INTO VFR BY THE END OF THIS TAF PERIOD AT DSM/ALO, BUT
HAVE TAKEN A SLOWER IMPROVEMENT APPROACH.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...JIMENEZ
LONG TERM...DE BRUIN
AVIATION...ANSORGE
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