525
FXUS63 KDMX 052337
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
537 PM CST MON JAN 5 2026
...UPDATED FOR THE 00Z AVIATION DISCUSSION...
KEY MESSAGES
- CLOUDS AND FOG EXPANDING ACROSS IOWA TONIGHT. PATCHY DRIZZLE
POSSIBLE SOUTHERN AND EASTERN HALF. LIGHT FROST ON ROADS
POSSIBLE NORTH. CONDITIONS IMPROVING TUESDAY.
- WARM ON WEDNESDAY, WITH HIGHS WELL INTO THE 50S CENTRAL AND
SOUTH.
- A LARGE WEATHER SYSTEM WILL MOVE THROUGH IN SUCCESSIVE WAVES
BETWEEN THURSDAY AND SATURDAY. PRECIPITATION IS LIKELY BUT THE
TIMING, TYPE, AND AMOUNT OF PRECIPITATION IS STILL UNCERTAIN.
DISCUSSION
ISSUED AT 207 PM CST MON JAN 5 2026
IT HAS BEEN A DAMP AND HAZY DAY ACROSS MUCH OF THE SERVICE
AREA. AN AREA OF LOW STRATUS CLOUDS HAS PERSISTED ACROSS OUR FAR
NORTHERN COUNTIES, WHILE A SEPARATE AREA OF LOW STRATUS CLOUDS
HAS SPREAD FROM MISSOURI INTO OUR SOUTHERN COUNTIES. BENEATH THE
LOW CLOUDS TEMPERATURES HAVE REMAINED IN THE 30S TO LOWER 40S,
BUT ELSEWHERE SOME AREAS AROUND CENTRAL IOWA HAVE RISEN WELL
INTO THE 40S AND EVEN HIT 50 AT A FEW STATIONS. VISIBILITIES
HAVE SLOWLY IMPROVED THROUGH THE DAY BUT SOME PATCHES OF LIGHT
HAZE PERSIST. MEANWHILE, A 500 MB SHORTWAVE TROUGH IS CROSSING
SOUTH DAKOTA AND NEBRASKA THIS AFTERNOON AND WILL MOVE OVER IOWA
TONIGHT. AS IT DOES SO, IT WILL SHARPEN A BIT AND INDUCE THE
DEVELOPMENT OF A WEAK SURFACE LOW SCOOTING FROM NORTHERN
MISSOURI INTO NORTHERN ILLINOIS OVERNIGHT. THE WESTERN FLANK OF
THIS LOW WILL COINCIDE WITH DEEPENING NEAR-SURFACE MOISTURE
STREAMING UP FROM THE GULF VIA MISSOURI AND KANSAS. THIS WILL
INTERACT WITH WEAK FORCING FOR ASCENT ASSOCIATED WITH THE
DEVELOPING SURFACE LOW, WHICH MAY BE SUFFICIENT TO GENERATE
LIGHT DRIZZLE FOR SEVERAL HOURS TONIGHT, MAINLY IN OUR SOUTHERN
AND EASTERN COUNTIES, BUT THERE MAY ALSO BE SOME IN THE NORTH AS
DEEPER MOISTURE SINKS DOWN FROM MINNESOTA AS WELL. HAVE
INCREASED POPS A BIT TO AROUND 10% AND INTRODUCED DRIZZLE
WORDING IN THE FORECAST ACCORDINGLY. FOG WILL ALSO EXPAND
OVERNIGHT AND SHOULD COVER A WIDER AREA THAN LAST NIGHT, GIVEN
THE INCREASING LOW-LEVEL MOISTURE AND CONTINUED LIGHT SURFACE
WINDS. HOWEVER, WITH SKIES ALREADY BEING NEARLY OVERCAST BY THIS
EVENING, RADIATIONAL COOLING WILL BE LIMITED AND IT REMAINS TO
BE SEEN HOW DENSE THE FOG WILL BECOME. HIGH-RESOLUTION MODELS
ARE PICKING UP ON THIS AS WELL, WITH MOST SOLUTIONS DEPICTING
WIDESPREAD FOG BUT ONLY PATCHES OF VISIBILITY BELOW 1/4SM,
EXCEPT PERHAPS JUST WEST OF OUR AREA NEAR THE MISSOURI RIVER
VALLEY WHERE SKIES MAY CLEAR AND ALLOW FOR MORE RADIATION/DENSE
FOG DEVELOPMENT. ASIDE FROM FOG CONCERNS, THERE IS ALSO SOME
POTENTIAL FOR FREEZING DRIZZLE AND/OR FROST FORMATION ON
ROADWAYS AS WE SAW THIS MORNING, MAINLY IN NORTHERN IOWA, THOUGH
IT REMAINS TO BE SEEN HOW MUCH OF THE AREA WILL STILL HAVE
SURFACE/ROAD TEMPERATURES BELOW FREEZING TONIGHT AS FORECAST LOW
TEMPS ARE RIGHT AROUND 31-32 DEGREES.
ON TUESDAY, PERSISTENT STRATUS CLOUDS AND LIGHT NORTHWEST
SURFACE FLOW WILL KEEP TEMPERATURES SIMILAR TO TODAY'S LEVELS,
BUT ON WEDNESDAY A MODEST THERMAL RIDGE WILL MOVE OVERHEAD AND
LIGHT SOUTHERLY SURFACE WINDS WILL RETURN, WHICH ALONG WITH MORE
CLEARING SHOULD ALLOW FOR SOME REBOUND AND AN UNSEASONABLY
PLEASANT DAY AS TEMPERATURES CLIMB INTO THE 50S ACROSS MUCH OF
THE AREA. HOWEVER, THIS WILL BE SHORT-LIVED AS A MORE ACTIVE
WEATHER PATTERN SETS IN AT THE END OF THE WORK WEEK.
BY THURSDAY MORNING, A BROAD 500 MB TROUGH WILL CARVE OUT OVER
THE WESTERN U.S. WITH SEVERAL VORTICITY MAXIMA SCATTERED
THROUGHOUT IT. A SOUTHERN STREAM WAVE WILL BE CROSSING THE TEXAS
PANHANDLE/OKLAHOMA REGION, WHILE A LEADING NORTHERN STREAM WAVE
MOVES OVER WESTERN ONTARIO, AND THE MAIN TROUGH AXIS REMAINS
OVER THE FAR WESTERN STATES. THE LEADING SOUTHERN WAVE WILL MOVE
NORTHEASTWARD WITH AN ATTENDANT SURFACE CYCLONE TRACKING ACROSS
MISSOURI, IOWA, AND ILLINOIS THURSDAY AFTERNOON AND EVENING. A
SWATH OF RAIN WILL ACCOMPANY THIS SYSTEM, AND IS LIKELY TO
AFFECT AT LEAST OUR SOUTHEASTERN HALF AND POSSIBLY FARTHER
NORTHWEST DEPENDING ON THE TRACK OF THE LOW. LITTLE IMPACT IS
ANTICIPATED DURING THIS TIME WITH TEMPERATURES REMAINING ABOVE
FREEZING. BY FRIDAY MORNING THE MAIN 500 MB TROUGH WILL BE
DEEPENING AND MOVING OVER THE ROCKIES, BUT IT WILL ONCE AGAIN BE
SPLIT INTO NORTHERN AND SOUTHERN COMPONENTS. THE DEGREE TO
WHICH THESE COMPONENTS REINTEGRATE, OR DO NOT, AS THE TROUGH
PROGRESSES INTO THE MIDWEST WILL SIGNIFICANTLY IMPACT SENSIBLE
IOWA WEATHER AT THE END OF THE WEEK. SUCCESSIVE RUNS OF THE
LONGER-RANGE MODELS HAVE SHOWN A LARGE DEGREE OF VARIABILITY IN
THEIR HANDLING OF THIS PHASING, AND AS A RESULT, WIDELY VARYING
SOLUTIONS FOR PRECIPITATION COVERAGE AND TYPE. SOME RUNS DEPICT
MEASURABLE SNOWFALL ACROSS MUCH OF OUR AREA, SOME DEPICT MORE
RAIN OR MIXED PRECIPITATION, AND THE 12Z GFS HAS EVEN COME IN
COMPLETELY DRY FOR IOWA FROM FRIDAY INTO SATURDAY. OVERALL
THERE IS A LIKELIHOOD OF PRECIPITATION FALLING ACROSS PARTS OF
IOWA AROUND FRIDAY AND FRIDAY NIGHT, BUT THE TIMING, AREAL
COVERAGE, AND AMOUNTS OF ANY SUCH SNOW ARE VERY MUCH IN
QUESTION AT THIS RANGE. WE WILL BE CLOSELY MONITORING THE SYSTEM
THROUGHOUT THIS WEEK.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 537 PM CST MON JAN 5 2026
VFR CONDITIONS REMAIN FOR ALL SITES EXCEPT KMCW AS LOW CLOUDS
AND FOG REMAIN, WHICH WILL GENERALLY BECOME MORE WIDESPREAD
THROUGHOUT MUCH OF IOWA THIS EVENING AND REMAIN INTO TUESDAY
MORNING. MORE SPECIFICALLY, FOG IS EXPECTED TO DEVELOP ALONG
WITH THE MOVEMENT OF LOW STRATUS OVERHEAD FROM SOUTH TO NORTH
THROUGH THE EVENING, WITH IFR AND EVEN LIFR CONDITIONS EXPECTED.
CONDITIONS ARE EXPECTED TO GRADUALLY IMPROVE MID TO LATE MORNING
TUESDAY, AS ANY FOG DISSIPATES AND CLOUDS DECREASE FROM
SOUTHWEST TO NORTHEAST. WINDS WILL INCREASE AT THE SAME TIME OUT
OF THE NORTHWEST, WITH GUSTS UP TO 15 KNOTS AT TIMES.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...LEE
AVIATION...BURY
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page