267
FXUS63 KDMX 201844
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
144 PM CDT TUE OCT 20 2026
KEY MESSAGES
- SEASONABLY WARM TEMPERATURES AND DRY CONDITIONS PREVAIL
THROUGH MID-WEEK. PATCHY FOG POSSIBLE IN THE MORNINGS.
- 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 112 PM CDT TUE OCT 20 2026
THE WEATHER IN IOWA REMAINS DRY AND SEASONABLY WARM AS 500 MB
RIDGING AND SURFACE HIGH PRESSURE MAINTAINS INFLUENCE TODAY. SUNNY
SKIES PREVAIL THROUGH MID-DAY, ALTHOUGH SCATTERED HIGH CLOUDS
WILL BEING TO SPREAD UP INTO SOUTHERN IOWA THIS EVENING AS A
SUBTLE SHORTWAVE PROPAGATES THROUGH THE UPPER LEVEL RIDGING.
THIS APPROACHING WAVE WILL BRING SLIGHTLY TIGHTENED PRESSURE
GRADIENTS TODAY, CAUSING LIGHT TO OCCASIONALLY BREEZY WINDS
AROUND 10 TO 15 MPH WITH GUSTS UP TO 20 MPH OVER NORTHWESTERN
IOWA. WITH THE APPROACHING WAVE, A FEW DETERMINISTIC MODEL
SOLUTIONS ARE DEPICTING SOME LIGHT RAIN OVER NORTHERN
MISSOURI/SOUTHERN IOWA EARLY WEDNESDAY MORNING. HOWEVER, DESPITE
THE SLIGHTLY BETTER SATURATION IN THE MID- LEVELS, THE LOW-
LEVELS REMAIN QUITE DRY OVERNIGHT. THIS WILL LIKELY LIMIT
ANYTHING MORE THAN A ROGUE SPRINKLE FROM REACHING THE SURFACE,
AND THEREFORE THE FORECAST REMAINS DRY OVERNIGHT. BY EARLY
WEDNESDAY MORNING, SOME GUIDANCE IS HINTING AT MORE ISOLATED FOG
DEVELOPMENT, BUT PROBABILITIES FOR LESS THAN A MILE ARE LOW
AROUND 30% OR LESS IN REFS GUIDANCE AND ONLY ABOUT 10% FROM THE
HREF, AGAIN FAVORING NORTHERN IOWA.
THE STATUS QUO CONTINUES THROUGH WEDNESDAY AND THURSDAY, WITH WARM,
DRY CONDITIONS DURING THE DAY AND EFFICIENT COOLING DURING THE
OVERNIGHT. NBM TEMPERATURES HAVE GENERALLY BEEN TOO MUTED WITH THE
MAGNITUDE OF THE DIURNAL CURVE DURING THIS PATTERN, BEING A FEW
DEGREES TOO COLD DURING THE DAYS, AND TOO WARM OVERNIGHT. THEREFORE,
HAVE CONTINUED PUSHING TEMPERATURES TOWARD THE UPPER END OF GUIDANCE
DURING THE DAYS AND LOWER END OF GUIDANCE AT NIGHT THROUGH THURSDAY.
THE END RESULT IS FORECAST HIGHS IN THE MID 70S AND ABOUT 10 TO 15
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR (NORMAL MAX TEMPS:
NORTHERN IOWA -58F, CENTRAL IOWA - 61F, SOUTHERN IOWA - 63F). LOWS
WILL GENERALLY BE IN THE 40S TO 50S, AROUND 10 DEGREES HIGHER THAN
NORMAL (NORMAL MIN TEMPS: NORTHERN IOWA - 35F, CENTRAL IOWA - 38F,
SOUTHERN IOWA - 42F). MORE FOG POTENTIAL IS EXPECTED WEDNESDAY NIGHT
INTO THURSDAY MORNING AS CLEAR SKIES AND LIGHT WINDS CONTINUE UNDER
THE SURFACE HIGH.
LONG TERM /FRIDAY THROUGH MONDAY/
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 /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1209 PM CDT TUE OCT 20 2026
VFR CONDITIONS PREVAIL TODAY WITH LIGHT TO OCCASIONALLY BREEZY
SOUTH SOUTHEASTERLY WINDS AROUND 10 TO 15 KTS, PRIMARILY NEAR
KFOD AND KMCW. WINDS GO CALM OVERNIGHT. SKIES REMAIN CLEAR
TODAY, WITH SCATTERED HIGH CLOUDS FILTERING THROUGH SOUTHERN
IOWA OVERNIGHT. THERE WILL ONCE AGAIN BE A POTENTIAL FOR
ISOLATED FOG WEDNESDAY MORNING, MAINLY NEAR KMCW, BUT
PROBABILITY IS TOO LOW TO INCLUDE IN TAF AT THIS TIME.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DODSON
LONG TERM...DODSON
AVIATION...DODSON
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