571
FXUS63 KDMX 011146
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
646 AM CDT WED APR 1 2026
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
KEY MESSAGES
- SHOWERS AND A FEW THUNDERSTORMS IN SOUTHERN IOWA THIS MORNING
WILL EXPAND ACROSS THE STATE THROUGH THIS AFTERNOON,
CONTINUING OVERNIGHT INTO THURSDAY. A WIDESPREAD 1-2+" OF RAIN
EXPECTED ACROSS IOWA BY THURSDAY EVENING.
- STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE IN IOWA ON MIDDAY
THURSDAY INTO THE AFTERNOON, MAINLY FROM CENTRAL TO EASTERN
IOWA. ALL SEVERE HAZARDS ARE POSSIBLE.
- ADDITIONAL SEVERE STORMS ON FRIDAY. AN ENHANCED RISK (LEVEL 3
OF 5) IS IN PLACE FOR CENTRAL AND SOUTHERN IOWA. ALL SEVERE
HAZARDS ARE POSSIBLE.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 324 AM CDT WED APR 1 2026
A BROAD SURFACE LOW SITS SOUTH OF THE IOWA/MISSOURI STATE LINE EARLY
THIS MORNING. THIS HAS RESULTED IN SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS MISSOURI AND INTO SOUTHERN IOWA. AS THIS LOW LIFTS
NORTH AND EAST THROUGH THE MORNING ACTIVITY WILL CONTINUE.
MEANWHILE, AN UPPER LEVEL TROUGH CONTINUES TO DEEPEN TO THE WEST. AS
IT MOVES EAST LATER THIS MORNING THETA-E ADVECTION WILL FUEL
WIDESPREAD SHOWERS ACROSS IOWA. THESE WILL LAST THROUGH THE
AFTERNOON AND OVERNIGHT. THE TRACK OF THE SYSTEM HAS ADJUSTED NORTH
SUCH THAT THE THREAT FOR A WINTRY MIX IS NORTH OF THE IOWA BORDER.
RAIN WILL CONTINUE THORUGH THURSDAY, FINALLY TAPERING OFF WEST TO
EAST IN THE AFTERNOON. AS UPPER LEVEL TROUGH SUPPORT ARRIVES ON
THURSDAY, DEEP MOISTURE TRANSPORT IS MAXIMIZED ACROSS IOWA.
PRECIPITABLE WATER IS 1-1.5" ACROSS IOWA DURING THIS TIME, WHICH IS
WELL ABOVE AVERAGE FOR AVAILABLE MOISTURE THIS TIME OF YEAR (ABOVE
THE 99TH PERCENTILE CLIMATOLOGY). EXPECT TO SEE A WIDESPREAD 1-2+"
OF RAIN ACROSS IOWA BY THE TIME PRECIPITATION ENDS ON THURSDAY. FOR
DETAILS ON THE POTENTIAL FOR HYDRO IMPACTS, SEE THE HYDROLOGY
SECTION BELOW.
ON THE SEVERE WEATHER SIDE OF THE HOUSE, POTENTIAL FOR TODAY IS LOW.
AS THE LOW APPROACHES LATE TONIGHT CONVERGENCE INCREASES ACROSS
MISSOURI AND TO THE SOUTH AND WEST. AN AXIS OF INSTABILITY DEVELOPS,
HOWEVER THE MODEL CONSENSUS IS THAT THIS DOES NOT MAKE IT TO IOWA.
SOUNDINGS ACROSS SOUTHERN IOWA ARE STRONGLY CAPPED AND DEEPLY
SATURATED WITH <100 J/KG OF CAPE SQUEEZED OUT OF A FEW MODELS. SPC
HAS MAINTAINED A MARGINAL (LEVEL 1 OF 5) RISK FOR SEVERE STORMS INTO
SOUTHERN IOWA FOR TODAY IN CASE THE BOUNDARY LIFTS FURTHER NORTH
THAN CURRENT DATA SUGGESTS.
THE SURFACE LOW ASSOCIATED WITH THE UPPER LEVEL TROUGH TRACKS ACROSS
IOWA THROUGH THE DAY ON THURSDAY. THE CURRENT TRACK PUTS IT ACROSS
CENTRAL IOWA BY 18Z AND INTO EASTERN IOWA BY 21Z. WINDS ALSO
INCREASE WITH A STRONG 850 MB LOW LEVEL JET AT 50-60+ KTS LASTING
THROUGH THE DAY FEEDING INTO CENTRAL AND EASTERN IOWA. IN SOUNDINGS,
LOW LEVEL DRY OUT QUICKLY BY MIDDAY WITH 35-40 KT WIND THROUGH THE
MIXED LAYER WITH OCCASIONAL 50+ KT TOWARDS THE TOP OF THE MIXED
LAYER. THIS WILL MAKE FOR A RATHER BREEZY DAY AHEAD OF THE COLD
FRONT. INSTABILITY INCREASES IN THE WARM SECTOR OF THE LOW FROM
CENTRAL TO SOUTHERN IOWA MIDDAY INTO THE AFTERNOON AS THE LOW MOVES
EAST WITH 1500+ J/KG OF "TALL, SKINNY" MUCAPE FROM CENTRAL TO
SOUTHERN IOWA WITH MIDLEVEL LAPSE RATES AROUND 7 C/KM. ALL MODES OF
SEVERE STORMS ARE POSSIBLE WITH STRETCHING EXPECTED IN THE
VICINITY OF THE TRIPLE POINT. WHILE CONVECTION WILL DEVELOPS IN
CENTRAL IOWA, EASTERN IOWA WILL HAVE THE GREATER ADVANTAGE OF
PEAK HEATING AND THIS IS WHERE THE SPC SLIGHT RISK (LEVEL 2 OF
5) HAS BEEN DRAWN. THERE IS ALSO SOME UNCERTAINTY AS TO HOW
MUCH THE MORNING SHOWER ACTIVITY AHEAD OF THE LOW WILL HINDER
AFTERNOON DEVELOPMENT.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED AT 324 AM CDT WED APR 1 2026
ANOTHER ROBUST WAVE MOVES INTO IOWA FRIDAY, QUICKLY ON THE HEELS OF
THE ONE EXITING EAST ON THURSDAY EVENING. THIS ONE AGAIN TAPS INTO
DEEP GULF MOISTURE INTO THE AREA WITH 2000-2500 J/KG CAPE ACROSS THE
SOUTHERN HALF OF IOWA AS THE SURFACE LOW TRACKS ALONG ESSENTIALLY
THE I-80 CORRIDOR. 35-40 KTS OF 0-6 KM SHEAR WILL BE AVAILABLE TO
HELP ORGANIZE CONVECTION. ADDITIONALLY, THE SURFACE LOW WILL AGAIN
TRACK ACROSS IOWA AND ENHANCE STRETCHING POTENTIAL. HODOGRAPHS
HAVE 200+ M2/S2 OF 0-1KM SRH. AS SUCH, ALL MODES OF SEVERE
WEATHER ARE POSSIBLE. ENVIRONMENT WOULD LIKELY SUPPORT INITIAL
MORE DISCRETE DEVELOPMENT GROWING UPSCALE INTO THE EVENING. SPC
HAS ISSUED A DAY 3 ENHANCED RISK (LEVEL 3 OF 5) FOR FRIDAY
ACROSS CENTRAL AND SOUTHERN IOWA. THESE STORMS WILL ALSO BRING
AN ADDITIONAL WIDESPREAD 1+" OF RAIN TO THE AREA.
SOME WRAP AROUND PRECIPITATION MAY SKIM NORTHERN IOWA ON SATURDAY.
OTHERWISE, DRIER AND COOLER CONDITIONS WILL BE IN PLACE SATURDAY AND
SUNDAY WITH HIGHS IN THE 40S AND 50S.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 646 AM CDT WED APR 1 2026
AVIATION CONDITIONS WILL DETERIORATE THROUGH TODAY. EAST WINDS
WILL GUST 20-25 KTS FROM LATE MORNING THROUGH THE TAF PERIOD.
MVFR STRATUS EXPANDS ACROSS IOWA LATE MORNING THROUGH MIDDAY.
FROM 18-00Z SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY EXPAND
IN COVERAGE ACROSS IOWA, BECOMING PREVAIL ACROSS ALL SITES
AROUND 00Z. PERSISTENT RAIN WILL LAST THROUGH THE END OF THE TAF
PERIOD, BECOMING HEAVIER OVERNIGHT. STRATUS DECK WILL LOWER TO
IFR OR LIFR AROUND 06Z AND VISIBILITY IN HEAVY RAIN WILL FALL TO
2-5SM AT TIMES. A FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE IN
SOUTHERN IOWA IMPACTING KDSM/KOTM AROUND 03-09Z. FURTHER
VISIBILITY RESTRICTIONS ARE POSSIBLE IN THUNDERSTORMS.
HYDROLOGY
ISSUED AT 301 PM CDT TUE MAR 31 2026
MULTI-DAY MODERATE TO HEAVY RAINFALL EVENT OVER THE NEXT
FEW DAYS WILL RESULT IN SHORT AND LONG TERM FLOODING CONSIDERATIONS
MAINLY ACROSS THE SOUTHEAST HALF OF THE CWA. SHORT TERM
CONSIDERATIONS INCLUDE POTENTIAL PONDING AND LOW-END FLASH
FLOODING. SOIL MOISTURE VALUES ARE GENERALLY RUNNING NEAR TO
BELOW NORMAL. THAT DATA COMBINED WITH THE QPF SUGGESTS PONDING
AND FLASH FLOOD CONCERNS WILL BE MAINLY RATE DRIVEN VS. AMOUNT
DRIVEN, WITH THE GREATEST RISK IN URBAN AREAS.
LONGER TERM CONSIDERATIONS INCLUDE POTENTIAL RIVER FLOODING.
NATIONAL WATER MODEL, HEFS AND QPF ENSEMBLE HYDROGRAPHS INDICATE THE
MOST LIKELY SCENARIO ON AREA RIVERS WILL BE MODERATE TO SIGNIFICANT
WITHIN-BANK RISES. A COUPLE LOCATIONS REACHING FLOOD STAGE ARE
POSSIBLE AS WELL. THE PEAKS ON MOST RIVERS WOULD OCCUR THIS
WEEKEND INTO EARLY NEXT WEEK. GREATER CONCERN IS THE NEXT
SEVERAL DAYS OF RAINFALL MAY SET THE STAGE FOR MORE SIGNIFICANT
IMPACTS GOING FORWARD SINCE THE CPC OUTLOOK FOR APRIL INCLUDES
ABOVE NORMAL PRECIP. ELEVATED SOIL MOISTURE AND STREAMS WILL NOT
REQUIRE AS MUCH RUNOFF TO BECOME IMPACTFUL IF THE WET PATTERN
CONTINUES.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...HAGENHOFF
LONG TERM...HAGENHOFF
AVIATION...HAGENHOFF
HYDROLOGY...ZOGG
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