841
FXUS63 KDMX 210843
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
343 AM CDT WED OCT 21 2026
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES CONTINUE THROUGH MID-WEEK. AREAS OF
PATCHY OVERNIGHT FOG POSSIBLE ONCE AGAIN WEDNESDAY MORNING.
- BREEZY CONDITIONS DEVELOP FRIDAY AND SATURDAY, ESPECIALLY IN
NORTHERN AND WESTERN IOWA. RAIN CHANCES RETURN TO THE SAME
AREAS SATURDAY.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 342 AM CDT WED OCT 21 2026
NOT MANY CHANGES TO THE FORECAST TODAY AS HIGH PRESSURE POSITIONED
OVER THE GREAT LAKES CONTINUES TO KEEP US FAIRLY QUIET! SKIES ACROSS
CENTRAL AND NORTHERN IOWA REMAIN MOSTLY CLEAR. MEANWHILE A WEAK
SHORTWAVE HAS INITIATED LIGHT SHOWERS ACROSS SOUTHWEST IOWA THIS
MORNING. RAIN TOTALS HAVE BEEN VERY LIGHT, WITH ONLY A FEW
LOCATIONS RECORDING A FEW HUNDREDTHS OF AN INCH. WE HAVE ADDED
SLIGHT PRECIPITATION CHANCES ACROSS THE SOUTH AS A FEW RAIN DROPS
HAVE BEEN ABLE TO OVERCOME THE DRY LOW-LEVEL AIR AND REACH THE
SURFACE. THIS SHORTWAVE WILL CONTINUE TO PUSH EASTWARD THROUGH
WEDNESDAY MORNING, BRINGING A MIX OF SUN AND CLOUDS TO SOUTHERN
IOWA. ANOTHER ITEM TO MONITOR WILL BE AREAS OF PATCHY FOG ACROSS
PORTIONS OF CENTRAL AND NORTHERN IOWA THIS MORNING. HOWEVER, TAKING
A CLOSER LOOK, WINDS WILL BE AROUND 5-8 MPH COMBINED WITH LIMITED
MOISTURE MAKE DENSE FOG UNLIKELY. REFS GUIDANCE CURRENTLY SHOWS A
UNDER 30% PROBABILITY OF VISIBILITIES DROPPING BELOW ONE MILE.
WEDNESDAY INTO THURSDAY
ONCE THE SHORTWAVE SLIDES THROUGH SOUTHERN IOWA, SKIES WILL TURN
MOSTLY SUNNY STATEWIDE WITH ANOTHER WARM DAY EXPECTED. HIGHS ARE
EXPECTED TO CLIMB INTO THE MID TO UPPER 70S LATER TODAY, WHICH IS
NEARLY 15 DEGREES ABOVE AVERAGE FOR THIS TIME OF YEAR. OUR AVERAGE
TEMPERATURE IS IN THE UPPER 50S TO LOWER 60S. THURSDAY WILL BE
ANOTHER WARM DAY, THOUGH WE EXPECT A BIT MORE CLOUD COVER ACROSS
NORTHWEST IOWA. STRONGER MOISTURE TRANSPORT WILL BE POSITIONED
ACROSS THE PLAINS ON THURSDAY; COMBINED WITH 850MB SOUTHWESTERLY
WINDS OVER NORTHWEST IOWA, THIS SHOULD YIELD A SLIGHT BUMP IN CLOUD
COVERAGE THROUGHOUT THE DAY.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED AT 112 PM CDT TUE OCT 20 2026
LATER THIS WEEK, A 500 MB TROUGH WILL MOVE INTO THE PACIFIC
NORTHWEST, DISLODGING AND MERGING WITH THE WEST COAST CUTOFF LOW
CURRENTLY BLOCKING THE OVERALL PATTERN IN THE US. BY FRIDAY, THIS
MERGED 500 MB TROUGH WILL PUSH INTO THE WESTERN CONUS AND ATTEMPT TO
SHOVE THE RIDGE OFF EASTWARD. HOWEVER, THIS RIDGE BECOMES SANDWICHED
BETWEEN THE WESTERN TROUGH AND ANOTHER SOUTHEASTERN US TROUGH,
PLACING IOWA RIGHT ALONG THE TROUGH/RIDGE INTERACTION. THE NET
RESULT FOR IOWA WILL BE A SOUTHWEST FLOW REGIME ALOFT, WITH SOME
INCREASING MOISTURE IN BOTH THE LOW AND MID-LEVELS AS A RESULT. AS
ENERGY EJECTS OUT OF THE TROUGH AND ALONG THE RIDGE THIS WEEKEND,
IOWA WILL SEE A FEW THINGS RESULT. FIRST, TIGHTENED LOW-LEVEL
PRESSURE GRADIENTS WILL PROMOTE BREEZY CONDITIONS BOTH FRIDAY AND
SATURDAY. THE BREEZIEST CONDITIONS WILL BE OVER THE NORTHERN AND
WESTERN PARTS OF THE STATE BOTH DAYS, AND COULD RESULT IN SOME
SLIGHTLY ELEVATED FIRE WEATHER CONCERNS OVER FAR NORTHWEST IOWA.
PRECIPITATION CHANCES ALSO MAKE A RETURN THIS WEEKEND, AS A COLD
FRONT IS PULLED INTO THE STATE BY THE SURFACE LOW PASSING TO OUR
NORTH. IOWA WILL BE FAIRLY WELL REMOVED FROM THE MAIN SYNOPTIC
FORCING OF THE LOW, BUT ASCENT ALONG THE COLD FRONT COMBINED WITH
INCREASED MOISTURE THROUGH THE COLUMN WILL PROVIDE SOME POTENTIAL
FOR RAIN SATURDAY INTO SUNDAY. RAIN PROBABILITIES WILL BE HIGHEST
ACROSS NORTHWESTERN IOWA NEARER TO THE MAIN MOISTURE TRANSPORT AXIS
(~40% CHANCE), WITH LOWER LIKELIHOOD WHERE DRIER CONDITIONS ARE
PRESENT FARTHER INTO CENTRAL IOWA (10 TO 20% CHANCE). SOUTHERN AND
EASTERN IOWA GENERALLY REMAIN DRY UNTIL THE BOUNDARY SLOWLY PUSHES
FARTHER SOUTH AND EAST INTO SUNDAY AND MONDAY. BEHIND THIS BOUNDARY,
TEMPERATURES BECOME MORE SEASONAL IN THE LOW 50S TO UPPER 60S,
ALTHOUGH EXACT TEMPERATURES WILL BE DEPENDENT ON HOW PROMINENT OF A
COLD PUSH RESULTS.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1042 PM CDT TUE OCT 20 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. LITTLE
CHANGE IN EXPECTATIONS SINCE LAST ISSUANCE. PATCHY FOG IS
POSSIBLE IN NORTHERN IOWA AGAIN WEDNESDAY MORNING AT KMCW,
HOWEVER POTENTIAL IS TOO LOW FOR INCLUSION AT THIS TIME. LIGHT
WIND FROM THE SOUTH OVERNIGHT WILL SHIFT TO FROM THE SOUTHWEST
WEDNESDAY AFTERNOON.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...TDR
LONG TERM...DODSON
AVIATION...HAGENHOFF
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