578
FXUS63 KDMX 172347
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
647 PM CDT WED SEP 17 2025
...UPDATED FOR THE 00Z AVIATION DISCUSSION...
KEY MESSAGES
- SCATTERED SHOWERS AND STORMS THIS AFTERNOON THROUGH TONIGHT.
A FEW STRONGER STORMS MAY PRODUCE HAIL OR GUSTY WINDS. POCKETS
OF HEAVY RAIN ARE POSSIBLE BUT WIDESPREAD FLOODING IS NOT
EXPECTED.
- SCATTERED SHOWERS AND STORM CHANCES CONTINUE FOR THE NEXT
SEVERAL DAYS. IT WILL NOT BE A WASHOUT WITH RAIN THE ENTIRE
PERIOD, BUT SCATTERED STORMS WILL BE POSSIBLE EACH DAY.
DISCUSSION
ISSUED AT 208 PM CDT WED SEP 17 2025
WIDESPREAD SCATTERED THUNDERSTORMS HAVE PERSISTED ACROSS THE AREA
WITH THE SURFACE LOW TO THE WEST SLOWLY EASING EAST. AN AXIS OF
INSTABILITY IN THE FORM OF 1000-1500 J/KG OF MLCAPE HAS DEVELOPED
FROM CENTRAL TO SOUTHERN IOWA WHERE CLEARING EARLIER IN THE DAY
ALLOWED FOR QUICK HEATING. ALONG THIS AXIS THE THUNDERSTORMS ARE
MORE ROBUST WITH PERIODIC STRONGER CORES. EVEN SO, SHEAR IS QUITE
WEAK AT 15-20 KTS OR LESS, LIMITING MORE ROBUST AND PERSISTENT STORM
DEVELOPMENT. AS SUCH THE SEVERE THREAT REMAINS LOW TODAY, HOWEVER A
FEW STRONGER CORES MAY PRODUCE HAIL OR GUSTY WINDS AS THOSE CORES
COLLAPSE. WHILE A FEW STRONGER CORES HAVE HAD PIXELS OF 60-65DBZ,
THIS HAS GENERALLY BEEN SHALLOW AND SHORT-LIVED TODAY. THESE MAY
HAVE PRODUCED BRIEF HAIL, HOWEVER NO REPORTS HAVE BEEN RECEIVED SO
FAR. A FEW OF THESE STRONGER CORES HAVE PRODUCED GUSTY WINDS WITH
ISOLATED GUSTS OF 30-40 MPH OBSERVED SO FAR.
ALOFT, THE UPPER LEVEL CUTOFF LOW WILL REMAIN ACROSS THE AREA FOR
THE NEXT SEVERAL DAYS (THROUGH FRIDAY AND INTO THE WEEKEND)
WITH CONTINUED CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS.
AS WE SAW YESTERDAY AND HAVE SEEN SO FAR TODAY, ACTIVITY IS MORE
WIDESPREAD THAN CAMS WOULD HAVE US BELIEVE AND EXPECT THAT THIS
TREND WILL CONTINUE UNTIL THE LOW FINALLY LIFTS OUT OF THE AREA
EARLY NEXT WEEK AND THE PATTERN CHANGES. THE ENVIRONMENT
REMAINS THE SAME THROUGH THE END OF THE WEEK AND WEEKEND, SO
PULSEY STORMS PRODUCING HAIL OR GUSTY WINDS WILL REMAIN POSSIBLE
WHILE WIDESPREAD STORMS ARE LESS LIKELY. WITH LITTLE FLOW,
STORM MOTIONS ARE FAIRLY SLOW. THESE SLOW MOVING STORMS ARE
EFFICIENT RAIN PRODUCERS IN AN ENVIRONMENT WITH DEEP WARM CLOUD
LAYERS OF 3500+ M AND PWATS OVER 1.5". AFTER SEVERAL FAIRLY DRY
WEEKS, FLOOD CONCERNS ARE LOW AT THIS TIME. WHILE CONVECTION
REMAINS SCATTERED, POCKETS OF HEAVY RAIN WITH SOME OF THE
STRONGER CORES MAY PRODUCE AREAS OF PONDING. ANY POTENTIAL FOR
FLASH FLOODING WOULD COME FROM STRONGER CELLS SETTING UP IN TOWN
WHERE DRAINAGE IS SLOWER.
ANOTHER UPPER LEVEL CUTOFF LOW DROPS ACROSS THE AREA EARLY NEXT
WEEK, PUSHING THE CURRENT ONE OUT OF THE AREA. DIFFERENCES
REMAIN WITH REGARDS TO TIMING AND PLACEMENT OF THIS LOW,
LENDING TOWARDS UNCERTAINTY IN PRECIPITATION CHANCES INTO EARLY
NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 647 PM CDT WED SEP 17 2025
SCATTERED SHOWERS AND STORMS ARE EXPECTED TO CONTINUE ACROSS
PORTIONS OF CENTRAL INTO SOUTHERN IOWA THIS EVENING, WITH MAIN
SHORT TERM IMPACTS AFFECTING KDSM, KOTM, AND KALO. BEYOND THE
EVENING ACTIVITY, THERE IS A LOW CHANCE FOR ADDITIONAL SHOWERS
AND STORMS THURSDAY, WITH CHANCES OVERALL LOW TO HAVE ENOUGH
CONFIDENCE TO INCLUDE AT ANY ONE SITE AT THIS TIME, THOUGH
CHANCES LOOK TO BE HIGHER NEAR THE END OF THE CURRENT TAF
PERIOD. WILL UPDATE AS NEEDED AS TRENDS CONTINUE TO BECOME MORE
CLEAR. THERE IS ALSO A LOW SIGNAL FOR FOG, MAINLY OVER PARTS OF
NORTHERN IOWA OVERNIGHT, SO WILL HAVE TO MONITOR THIS OVER THE
NEXT SEVERAL HOURS.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HAGENHOFF
AVIATION...BURY
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