300
FXUS63 KDMX 221721
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1221 PM CDT SAT AUG 22 2026
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- AREAS OF PATCHY FOG POSSIBLE THIS MORNING.
- A COOLER, DRIER AIRMASS SETTLES OVER IOWA TODAY, BRINGING
COMFORTABLE CONDITIONS AND SLIGHTLY BELOW AVERAGE TEMPERATURES.
- RAIN AND THUNDERSTORM CHANCES RETURN TO THE STATE LATE
SUNDAY.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 125 AM CDT SAT AUG 22 2026
THE COLD FRONT HAS CLEARED CENTRAL IOWA, WITH A DRY AND COMFORTABLE
AIRMASS BUILDING IN BEHIND IT. QUIET CONDITIONS ESTABLISHED
OVERNIGHT WILL PERSIST THROUGH SATURDAY AFTERNOON. PATCHY FOG
REMAINS POSSIBLE EARLY SATURDAY MORNING, THOUGH CONFIDENCE IN
WIDESPREAD COVERAGE IS LIMITED DUE TO DRY AIR ADVECTING IN FROM THE
NORTH. THE HIGHEST PROBABILITY FOR FOG WILL RESIDE ALONG LOW RIVER
VALLEYS AND PORTIONS OF SOUTHERN IOWA, WHERE BOUNDARY LAYER MOISTURE
AND HIGHER DEW POINTS LINGER.
SURFACE HIGH PRESSURE EXPANDING ACROSS NORTHERN PLAINS WILL MAINTAIN
COMFORTABLE CONDITIONS TODAY, KEEPING DEW POINTS IN THE 50S TO LOWER
60S. HIGH TEMPERATURES WILL BE NOTICEABLY COOLER THAN FRIDAY,
DIPPING SLIGHTLY BELOW SEASONAL AVERAGES IN A FEW LOCATIONS; MAKING
FOR A GREAT DAY TO BE OUTDOORS. QUIET WEATHER CONTINUES SATURDAY
NIGHT, THOUGH CLOUD COVER WILL GRADUALLY INCREASE ACROSS WESTERN
IOWA AS A WEAK SHORTWAVE PASSES OVER THE HIGH PLAINS. MEASURABLE
PRECIPITATION IS UNLIKELY WITH THIS FEATURE, BUT BETTER CHANCES FOR
SHOWERS AND THUNDERSTORMS ARRIVE SUNDAY NIGHT.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 230 PM CDT FRI AUG 21 2026
IOWA REMAINS SEATED BETWEEN A RIDGE CENTERED OVER THE FOUR CORNERS
REGION AND A TROUGH OVER THE GREAT LAKES. IF EITHER OF THESE SYSTEMS
SHIFT, THAT WILL CHANGE HOW FAR EAST OR WEST MOISTURE GETS BACK INTO
THE AREA BY SUNDAY NIGHT, WHICH IS WHEN THE NEXT SHORTWAVE LOOKS TO
MOVE THROUGH, POTENTIALLY BRINGING MORE PRECIPITATION CHANCES INTO
SUNDAY MORNING. AT THE MOMENT, HOWEVER, DETERMINISTIC GUIDANCE IS
STILL STRUGGLING WITH THE TIMING OF THIS SYSTEM. WITH THIS COMES
SOME DEGREE OF DISAGREEMENT WITH PLACEMENT, ALL OF WHICH WILL BE
BETTER ASSESSED IN THE COMING DAYS. THIS UPPER LEVEL PATTERN LOOKS
TO REMAIN RATHER STAGNANT, WITH THE POTENTIAL FOR ADDITIONAL
SHORTWAVES TO MOVE THROUGH THE REGION NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 1221 PM CDT SAT AUG 22 2026
TAFS ARE VFR WITH NO AVIATION IMPACTS ANTICIPATED. THERE IS A
VERY LOW CHANCE (<20%) OF SHALLOW FOG AROUND SUNRISE SUNDAY, BUT
BOTH PROBABILITY AND COVERAGE/IMPACT IF IT WERE TO OCCUR ARE TOO
LOW FOR ANY TAF MENTION.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...TDR
LONG TERM...67
AVIATION...LEE
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