697
FXUS63 KDMX 070444
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1044 PM CST TUE JAN 6 2026
...UPDATED FOR THE 06Z AVIATION DISCUSSION...
KEY MESSAGES
- FOG AGAIN TONIGHT, MAINLY IN THE NORTHEAST.
- LARGE TEMPERATURE SPREAD FOR HIGHS WEDNESDAY, WITH RECORD
HIGHS POSSIBLE.
- ACTIVE WEATHER TO FOLLOW, WITH RAIN THURSDAY, TRANSITIONING TO
WINTER WEATHER THURSDAY NIGHT, THEN AGAIN FRIDAY NIGHT AND
SATURDAY.
DISCUSSION
ISSUED AT 252 PM CST TUE JAN 6 2026
STUBBORN FOG AND STRATUS CONTINUED TO COVER ROUGHLY THE EASTERN HALF
OF THE STATE THIS AFTERNOON. A SUBTLE SHORTWAVE WILL BRING A BRIEF
WINDOW OF RAIN CHANCES TO THE FAR NORTH THIS EVENING, BUT ENOUGH DRY
AIR IN THE INVERSION EXISTS THAT QPF IS LITTLE TO NONE. A SURFACE
RIDGE WILL MOVE ACROSS THE STATE OVERNIGHT TONIGHT. THE LIGHT AND
VARIABLE WINDS WILL LEAD TO THE FORMATION OF ANOTHER ROUND OF DENSE
FOG TONIGHT, MOSTLY IN THE NORTHEAST HALF OF THE AREA, WITH
UNCERTAINTY STARTING AT A NW-TO-SE LINE FROM ESTHERVILLE TO DES
MOINES TO OTTUMWA. WEST OF THESE CITIES WILL BE WARMER, DRY AIR
THAT WILL WORK TO MOVE FOG/STRATUS AWAY EARLIER WEDNESDAY.
UNFORTUNATELY FOR THE NORTHEAST PART OF THE STATE, STRATUS WILL
LIKELY BE STUBBORN TO LEAVE TOMORROW. A LARGE TEMPERATURE
GRADIENT EXISTS ACROSS THE STATE, WITH HIGHS APPROACHING 60 IN
SOUTHWEST IOWA, CHALLENGING RECORDS. NORTHEAST IOWA MAY NOT GET
OUT OF THE LOW 40S TOMORROW. HAVE LEANED TOWARDS THE 90TH
PERCENTILE OF GUIDANCE IN THE WARM SECTOR TOMORROW AS DEW POINTS
IN THE 20S AND DRY GROUND TEND TO LEAD TO EFFICIENT MIXING AND
OVERPERFORMING HIGHS.
AN ACTIVE SECOND HALF OF THE WEEK IS IN STORE. A CLOSED LOW OFF THE
WEST COAST WILL ENCOURAGED A PROLONGED PERIOD OF TROUGHING IN THE
WESTERN CONUS, DRAGGING ANOTHER FEATURE FROM THE PNW INTO THE FOUR
CORNERS. THE FIRST FEATURE WILL RIDE THE SEASONALLY STRONG UPPER
JET, TILTING IT NEGATIVELY AS IT ARRIVES IN THE REGION. THE JET WILL
ROUND THE BASE OF THE FEATURE THURSDAY AFTERNOON, BUT KINEMATICS FOR
SEVERE WEATHER WILL STAY SOUTH AND EAST OF THE STATE AT THIS TIME.
PWATS OVER AN INCH WILL COME INTO SOUTHEAST IOWA AS WELL AS MIDLEVEL
LAPSE RATES GREATER THAN 7 C/KM. SO, THERE COULD BE EFFICIENT RAIN
AND MAYBE EVEN A FEW THUNDERSTORMS. NBM GUIDANCE RIGHT NOW HAS A 25-
30% OF SEEING AN INCH OF RAIN IN SOUTHEAST IOWA. THURSDAY HAS ALSO
TRENDED WARMER, SO THE TRANSITION TIME FOR SNOW ON THE NORTHWEST
SIDE HAS BEEN DELAYED. SNOWFALL AMOUNTS WILL BE CHALLENGING AS
THE SECONDARY DGZ IS IN PLAY WITH A WARM NEAR-SURFACE PROFILE.
THE AFOREMENTIONED SECOND WAVE WILL BE JOINED BY A NORTHERN STREAM
FEATURE. THEY LOOK TO COMBINE THIS WEEKEND SOMEWHERE IN THE REGION,
INTENSIFYING AS THEY DO. BETTER CONGRUENCE WAS SEEN IN DETERMINISTIC
GUIDANCE TODAY FOR FRIDAY NIGHT, BRINGING THE DEFORMATION ZONE OF
THE DEVELOPING SURFACE LOW SOMEWHERE IN THE STATE, YIELDING A
RAIN/SNOW MIX. TEMPERATURES FALL GOING INTO SATURDAY AND THE
EXTENDED DURATION OF PRECIPITATION WILL DEPEND ON HOW MUCH THE WARM
CONVEYOR BELT WRAPS AROUND (25-25% POPS ON SATURDAY FOR NOW). THERE
MAY BE AN ADDITIONAL BOUNDARY PIVOTING AROUND THE MATURE CYCLONE
THAT COULD USE THIS MOISTURE. WITH HOW DYNAMIC THE HEIGHT FALLS ARE
(AROUND 15 TO 20 DAM) WILL HAVE TO WATCH HOW THE SIMULATED SURFACE
LOW TRACK AND INTENSITY CHANGES THIS WEEKEND, AS IT WILL HAVE
IMPLICATIONS FOR HOW MUCH WIND WILL BE A FACTOR AS WELL.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1044 PM CST TUE JAN 6 2026
DENSE FOG BEGAN TO FORM OVER PORTIONS OF SOUTHEAST IOWA LATE
TUESDAY NIGHT, WHICH IS IMPACTING KOTM, AND IS EXPECTED TO
EXPAND ACROSS EASTERN IOWA, INCLUDING AT KMCW AND KALO THROUGH
MUCH OF WEDNESDAY MORNING. VISIBILITIES BELOW A HALF TO QUARTER
MILE ARE EXPECTED, LEADING TO IFR AND ISOLATED LIFR CONDITIONS
AT TIMES. OTHERWISE, UNCERTAINTY ON THE FOG COVERAGE FURTHER
WEST AT KDSM AND ESPECIALLY AT KFOD REMAINS, WITH IMPACTS IF ANY
LOOKING TO GENERALLY BE PATCHY FOG AND LOW PROBABILITIES FOR
DENSE FOG AT THIS TIME. WILL CONTINUE TO MONITOR THROUGH THE
NIGHT INTO THE MORNING, AND UPDATE AS NEEDED. OTHERWISE,
CONDITIONS IMPROVE FOR ALL SITES AFTER 15-18Z, WITH VFR
CONDITIONS EXPECTED. WINDS OUT OF THE SOUTH TO SOUTHWEST ARE
EXPECTED THROUGH THE DAY, WITH WINDS INCREASING INTO LATE
MORNING THROUGH THE AFTERNOON AS GUSTS REACH UP TO 15 KNOTS AT
TIMES.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...JIMENEZ
AVIATION...BURY
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