355
FXUS63 KDMX 210421
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1021 PM CST SAT DEC 20 2025
...UPDATED FOR THE 06Z AVIATION DISCUSSION...
KEY MESSAGES
- WARMING TREND CONTINUES SUNDAY AND LASTS FOR MUCH OF CHRISTMAS
WEEK.
- LOW CHANCE (<20%) OF LIGHT PRECIPITATION WEDNESDAY, BUT
OTHERWISE DRY.
- FOG POTENTIAL EXISTS FOR SNOWPACKED AREAS IN NORTHERN IOWA
THROUGH THE WEEK.
DISCUSSION
ISSUED AT 159 PM CST SAT DEC 20 2025
GUSTY WINDS FOLLOWED THE FRONT THIS AFTERNOON, MAINLY IN THE NORTH.
ITS INFLUENCE WAS FELT LESS IN SOUTHERN AND SOUTHWEST IOWA WHERE
TEMPERATURES COULD STILL RECOVER INTO THE 40S. THE SURFACE HIGH
MENTIONED PREVIOUSLY HAS TRENDED MORE WEST IN TRACK, INFLUENCING
MORE OF THE STATE TONIGHT, MEANING LOWS WILL BE COOLER. SOUTHWEST
FLOW INVADES RIGHT AT SUNRISE SUNDAY AND RECOVERS HIGHS CLOSE TO
WHERE THEY WERE TODAY. BOOSTED HIGHS TO THE 90TH PERCENTILE AS HIGHS
HAVE OUTPERFORMED IN THIS WARM, DRY REGIME THE PAST FEW DAYS.
NORTHEAST IOWA WILL REMAIN ON THE COOLER SIDE DUE TO THE EXTENDED
INFLUENCE OF THE HIGH. SOUTHWEST FLOW CONTINUES SUNDAY NIGHT WHICH
WILL KEEP SOUTHWEST IOWA ABOVE FREEZING. A PUSH OF THETA-E ADVECTION
WILL SPAWN CLOUDS AND PERHAPS SOME PRECIPITATION ALONG ITS LEADING
EDGE FOR FAR NORTHERN IOWA, BUT PRECIPITATION CHANCES ARE VERY LOW
(<10%). CONDENSATION PRESSURE DEFICITS WILL DECREASE WITH TIME
WITHIN THE CLOUD LAYER, BUT THE BETTER CHANCE OF DRIZZLE FORMING IS
OVER EASTERN IOWA, AT THIS TIME. SNOWMELT WILL TAKE PLACE AS SKIES
CLEAR MONDAY AFTERNOON. WET BULB TEMPERATURES WILL RISE ABOVE
FREEZING IN NORTHERN IOWA AND, GIVEN OVERPERFORMING TRENDS THIS
WEEKEND, THEY COULD BE HIGHER THAN CURRENTLY FORECASTED,
INCREASING SNOWMELT. FOG CHANCES START ENTERING THE PICTURE AT
THIS POINT.
UPPER LEVEL RIDGING CONTINUES TO FAVOR A WARMING TREND FOR NEXT WEEK
AND AS MENTIONED IN THE PREVIOUS DISCUSSION, THERE ARE SOME
CHALLENGES FOR HIGHS IN NORTHERN IOWA THIS WEEK. NOTICE THE
TEMPERATURE SPREAD, FOR EXAMPLE, ON TUESDAY. HIGH PRESSURE WILL
SLIDE ACROSS THE UPPER MIDWEST AND INTRODUCE NORTHERLY FLOW IN
NORTHERN IOWA. PAIRED WITH REMAINING SNOW PACK, IT JUSTIFIES
TEMPERATURES STAYING IN THE 30S. ANOTHER WINDOW FOR STRATUS (AND
PERHAPS SOME DRIZZLE) ARRIVES WITH THE NEXT PUSH OF MOISTURE ON
WEDNESDAY. SUMMING UP PROBABILITIES BY THE TIME CHRISTMAS DAY ROLLS
AROUND, ENSEMBLE GUIDANCE HAS >50% OF AT LEAST 70% CLOUD COVER
IN NORTHERN AND EASTERN IOWA FOR ALMOST ALL OF TUESDAY-THURSDAY.
WITH THIS IN MIND, THE WARMUP FOR THIS PORTION OF THE STATE
WILL BE LIMITED, BUT RECORD HIGHS STILL LOOK TO BE CHALLENGED
ACROSS CENTRAL AND SOUTH BY CHRISTMAS.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1017 PM CST SAT DEC 20 2025
VFR CONDITIONS WILL CONTINUE THIS PERIOD. THERE IS A LOW CHANCE
/20-30%/ FOR SHALLOW GROUND FOG TO DEVELOP ACROSS PORTIONS
CENTRAL IOWA, ESPECIALLY NEAR KFOD. LEFT OUT OF THE TAF FOR NOW
DUE TO LOW CONFIDENCE. OTHERWISE, LIGHT WINDS OVERNIGHT WILL
TRANSITION TO SOUTHERLY ON SUNDAY MORNING.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...FOWLE
AVIATION...JIMENEZ
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