363
FXUS63 KDMX 231733
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1133 AM CST TUE DEC 23 2025
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- CONFIDENCE REMAINS HIGH IN ABOVE NORMAL TEMPERATURES THROUGH
SATURDAY.
- DRIZZLE POSSIBLE AT TIMES CHRISTMAS EVE THROUGH CHRISTMAS DAY
WITH MOST LIKELY AREA OVER EASTERN IOWA. ALSO, MONITORING FOG
POTENTIAL TONIGHT THROUGH CHRISTMAS DAY.
- MUCH COLDER AIR ARRIVES ON GUSTY WINDS FROM THE NORTHWEST SATURDAY
NIGHT INTO SUNDAY WITH THE COLD LINGERING INTO MONDAY.
DISCUSSION
ISSUED AT 254 AM CST TUE DEC 23 2025
UPPER LEVEL WATER VAPOR IMAGERY FROM GOES-EAST CONTINUES TO SHOW THE
BROAD RIDGE OVER MUCH OF THE CONUS WITH MOISTURE FLOWING FROM THE
EASTERN PACIFIC INTO THE NORTHERN ROCKIES AND THEN INTO THE
NORTHEASTERN US. IT'S A FAST FLOW WITH A 150 KNOT, 250MB RAP
ANALYZED JET STREAM OVER THE NORTHERN ROCKIES. THIS FAST FLOW IS
SENDING HIGH CLOUDS OVER THE STATE EARLY THIS MORNING AS SEEN IN THE
GOES-EAST NIGHTTIME MICROPHYSICS RGB IMAGERY. AT THE SURFACE OVER
IOWA, OBSERVATIONS SHOW A WEAK COLD FRONT HAS ARRIVED OVER THE
NORTHERN PORTION OF THE STATE AND IS BRINGING IN SLIGHTLY COOLER
AIR. THE POTENTIAL DROP OF TEMPERATURES IS BEING OFFSET BY THE
AFOREMENTIONED HIGH CLOUDS. THESE CLOUDS ARE ALSO TEMPERING THE FOG
FORMATION WITH VISIBILITIES GENERALLY ABOVE 6 MILES OBSERVED IN
PARTS OF NORTH CENTRAL IOWA. WITH THIS COOL FRONT DROPPING THROUGH
THE STATE TODAY AND NORTHERLY FLOW, HIGHS IN MOST CENTRAL IOWA TOWNS
WILL NOT BE QUITE AS WARM AS YESTERDAY. CURRENT FORECAST HIGHS ARE
STILL ANYWHERE FROM AROUND 5 TO 10 DEGREES ABOVE NORMAL OVER
NORTHERN IOWA AND THE LINGERING SNOWPACK TO AROUND 15 DEGREES ABOVE
NORMAL OVER CENTRAL AND SOUTHERN IOWA. THERE IS ALSO AN AREA OF
STRATUS OVER NORTH DAKOTA THAT IS CURRENTLY PUSHING SOUTHEASTWARD
TOWARDS THE STATE. MODELS OUTSIDE OF THE RAP ARE STRUGGLING TO
RESOLVE THIS PROPERLY SO WILL BE KEEPING AN EYE ON THIS FOR
TEMPERATURES THIS AFTERNOON. THE FORECASTED TEMPERATURES WILL BE
SUFFICIENT FOR SNOWMELT FOR AT 4 TO 8 HOURS THIS AFTERNOON AND EARLY
EVENING.
THE MID-LEVEL RIDGE PATTERN WILL STAY OVER OUR REGION THROUGH THE
END OF THIS HOLIDAY WEEK WITH WEAK SHORTWAVE TROUGHS MOVING THROUGH
THE RIDGE IN THE FAST FLOW. AT THE SAME TIME, WAVES OF LOW LEVEL
THETA-E ADVECTION WILL DIRECT VERY MILD AND WARM AIR INTO THE REGION
ALONG WITH INCREASING LEVELS OF NEAR SURFACE MOISTURE. THE FIRST
WAVE OF THETA-E ADVECTION WILL ARRIVE TONIGHT AS WINDS BECOME FROM
THE SOUTHEAST AND INCREASE FROM AROUND OR UNDER 5 MPH THIS EVENING
TO 5 TO 10 MPH BY SUNRISE CHRISTMAS EVE MORNING. CONFIDENCE IN FOG
FORMATION IS LOW AS WIND CONDITIONS ARE MORE FAVORABLE IN THE
EVENING, BUT DEWPOINT DEPRESSIONS ARE RELATIVELY LARGE COMPARED TO
EARLY WEDNESDAY MORNING. OTHERWISE, FORECAST SOUNDINGS AND CROSS
SECTIONS SHOW NEAR SURFACE MOISTURE ARRIVING FROM SOUTHWEST TO
NORTHEAST LATE TONIGHT THROUGH CHRISTMAS EVE, WHICH WILL RESULT IN
AN AREA OF LOW LEVEL STRATUS CLOUDS PUSHING OVER THE STATE. FURTHER,
AS HAS BEEN MENTIONED FOR SEVERAL DAYS, CONDITIONS CONTINUE TO LOOK
FAVORABLE FOR DRIZZLE FOR PART OF WEDNESDAY OVER AT LEAST EASTERN
IOWA. MOISTURE DEPTH HAS SWUNG BACK A BIT HIGHER THAN THIS TIME
YESTERDAY AND IS NOW AROUND OR A BIT ABOVE 1KM. WITH WEAK LIFT FROM
A PASSING SHORTWAVE TROUGH COLLOCATED IN THE SATURATION AND
DIRECTIONAL SHEAR FOR COLLISION COALESCENCE, THIS SHOULD AID IN
DRIZZLE PRODUCTION. MODELS CONTINUE TO SHOW THE DRIZZLE QPF SIGNAL
AND WHILE SOME MODELS ARE MUCH MORE EXPANSIVE IN THEIR QPF
AREA/DRIZZLE SIGNAL, THE DEPTH OF MOISTURE IN MOST MODEL FORECAST
SOUNDINGS ARE NOT SUPPORTIVE OF THAT WIDESPREAD SO HAVE FOCUSED THE
CHANCES PRIMARILY OVER OUR EASTERN FORECAST AREA - ROUGHLY HIGHWAY
63 AND POINTS EAST. TEMPERATURES HAVE VARIED LITTLE ON WEDNESDAY THE
PAST FEW DAYS, THOUGH DO NOTE RELATIVELY LARGER SPREADS BETWEEN THE
25TH AND 75TH PERCENTILES OVER SOUTHERN IOWA. GIVEN THE AMOUNT OF
LOW LEVEL SATURATION, LATEST HREF IS SHOWING INCREASING PROBABILITY
OF VISIBILITY BELOW A HALF A MILE OVER NORTHWEST IOWA SO THAT WILL
BE SOMETHING WE WILL BE MONITORING FOR TRAVELING IOWANS AND REINDEER.
AS WE MOVE INTO CHRISTMAS DAY, CONCERNS ABOUT CLOUD COVER AND
DRIZZLE AND ITS IMPACTS ON HIGH TEMPERATURES THAT HAVE BEEN CONVEYED
SINCE THIS WEEKEND ARE LOOKING LIKELY TO COME TO FRUITION. NOW, IT
WILL STILL BE A MILD CHRISTMAS, BUT ONE THAT IS SHROUDED IN CLOUDS
AND PERHAPS AREAS OF DRIZZLE OR EVEN FOG AT TIMES. THE CLOUD COVER
FROM CHRISTMAS EVE WILL LINGER OVERNIGHT INTO CHRISTMAS DAY WITH THE
LOW LEVEL SATURATION IN CROSS SECTIONS AND FORECAST SOUNDINGS STILL
PRESENT. DRIZZLE POTENTIAL REMAINS, BUT IS A BIT LESS CERTAIN WITH
MOISTURE DEPTH, AT LEAST THROUGH THE DAY. WITH ANOTHER SURGE OF
THETA-E ADVECTION AHEAD OF THE NEXT SHORTWAVE TROUGH AND ASSOCIATED
SURFACE LOW PRESSURE LATE CHRISTMAS DAY INTO THE NIGHT, THIS LOOKS
TO INCREASE MOISTURE DEPTH FOR EITHER DRIZZLE OR PERHAPS LIGHT RAIN
WITH THE FAVORED AREA ONCE AGAIN BEING EASTERN IOWA. NATIONAL BLEND
OF MODELS HAS FINALLY CAUGHT ONTO THE "COOLER" SOLUTION AND IS MUCH
MORE IN LINE WITH ENSEMBLE GUIDANCE ALONG WITH A MORE REASONABLE
SPREAD OF 4 TO 7 DEGREES.
THE CLOUDS WILL FINALLY START TO BREAK UP, AT LEAST OVER WESTERN AND
SOUTHERN IOWA, ON FRIDAY AS LARGE SCALE SUBSIDENCE FOLLOWS BEHIND
THE LOW ALONG WITH LIGHT BREEZES FROM THE NORTHWEST. CLOUDS MAY BE
STUBBORN TO LEAVE PORTIONS OF NORTHERN AND EASTERN IOWA AS LOW LEVEL
SATURATION PERSISTS. TEMPERATURES WILL REMAIN MILD AND ABOVE NORMAL
FRIDAY AND SATURDAY. THIS WILL CHANGE LATE SATURDAY INTO SUNDAY AS A
STRONG COLD FRONT BLASTS THROUGH THE STATE. FORECAST STILL HAS DRY
CONDITIONS WITH THE STRONGEST FORCING REMAINING NORTH OF THE STATE,
BUT SOME ENSEMBLE GUIDANCE BRINGS LIGHT QPF INTO AT LEAST
NORTHEASTERN IOWA. SUNDAY WILL BE MUCH COLDER WITH GUSTY WINDS FROM
THE NORTHWEST AS TEMPERATURES HEAD BACK TO AT LEAST NORMAL AND
LIKELY BELOW NORMAL. THE COLD CONDITIONS WILL LAST INTO MONDAY, BUT
THIS IS A PASSING COLD SHOT AS TEMPERATURES LOOK TO MODERATE AS WE
HEAD TOWARDS THE FINAL DAYS OF 2025.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1128 AM CST TUE DEC 23 2025
VFR CONDITIONS PREVAIL OVER THE AREA TODAY AND WILL REMAIN THAT
WAY THROUGH THE AFTERNOON AT KALO, KDSM AND KOTM. A STRATUS DECK
WITH CEILINGS AROUND 700 TO 1200 FT IS DRIFTING SOUTHEASTWARD
OVER MINNESOTA, LOOKING TO BRING MVFR TO IFR CONDITIONS TO KMCW
AND POTENTIALLY KFOD LATER THIS AFTERNOON/EVENING. IN ADDITION
TO THIS STRATUS DECK, PATCHY FOG MAY DEVELOP THIS EVENING AND
OVERNIGHT NEAR BOTH SITES. AS WE GET INTO WEDNESDAY, INCREASING
LOW LEVEL CLOUDS AND OCCASIONAL DRIZZLE WILL LEAD TO MVFR TO
IFR CONDITIONS THROUGH THE DAY.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...ANSORGE
AVIATION...DODSON
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