163
FXUS63 KDMX 061745
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CST TUE JAN 6 2026
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- CLOUDS AND DENSE FOG THIS MORNING WITH PARTS OF CENTRAL AND
SOUTHWEST IOWA CLEARING OFF LEADING TO A WIDE TEMPERATURE
RANGE ACROSS THE AREA TODAY.
- MUCH WARMER AND PERHAPS A RUN AT RECORD HIGH TEMPERATURES ON
WEDNESDAY.
- ACTIVE WEATHER THURSDAY THROUGH SATURDAY WHICH WILL EVENTUALLY
BRING WINTER WEATHER BACK TO THE AREA AFTER AN INITIAL PERIOD
OF RAIN.
DISCUSSION
ISSUED AT 351 AM CST TUE JAN 6 2026
WEAK AREA OF LOW PRESSURE IS MOVE EAST/NORTHEAST NEAR THE QUAD
CITIES CURRENTLY. A BROAD AREA OF STRATUS AND FOG EXISTS BEHIND THE
SYSTEM ACROSS A LARGE PORTION OF IOWA. LIGHT DRIZZLE HAS BEEN
ONGOING OVER PARTS OF CENTRAL AND SOUTHEAST IOWA WHERE THIS STRATUS
LAYER IS THE THICKEST. FORTUNATELY TEMPERATURES AND DEW POINTS IN
THAT AREA ARE IN THE UPPER 30S TO LOW 40S ALONG WITH ROAD
TEMPERATURES ABOVE FREEZING. MUCH OF THE FOG IS DENSE FOG AND HAVE A
DENSE FOG ADVISORY TO COVER THAT. THIS NORTHERN EDGE OF THE
FOG/STRATUS HAS BEEN EXPANDING NORTHWARD WHILE ANOTHER AREA OF FOG
AND STRATUS OVER MINNESOTA AND EASTERN SOUTH DAKOTA IS SETTLING
SOUTH SO ANY CLEAR AREAS ACROSS THE NORTH WILL FILL IN SOON.
SPEAKING OF NORTHERN IOWA, A FEW LIGHT SHOWERS ARE MOVING OVER THAT
PART OF THE STATE WITH THE MAJORITY OF THE PRECIPITATION FARTHER
NORTH INTO MINNESOTA. A DEEP DRY LAYER REMAINS BELOW THE HYDROMETEOR
PRODUCING CLOUDS SO EVAPORATION IS OCCURRING BUT HAVE HAD A FEW
OBSERVATIONS OF LIGHT FREEZING RAIN. SO FAR NO IMPACTS HAVE BEEN
REPORTED BUT A FEW ICY SPOTS ARE CERTAINLY POSSIBLE WITH ROAD
TEMPERATURES IN THE 30-32 DEGREE RANGE.
MUCH LIKE MONDAY, HIGH TEMPERATURES TODAY ARE GOING TO BE HIGHLY
DEPENDENT ON THE EVOLUTION OF THE STRATUS AND FOG TODAY. WHILE
IT WAS PREVIOUSLY MENTIONED THAT THE STATUS AND FOG WAS
EXPANDING NORTHWARD, THE MEAN MASS IS PROGRESSING SOUTHEAST WITH
THE LIGHT NORTHWEST STEERING FLOW, WHICH IS SHOWING UP NICELY
IN THE GOES 16 NIGHTTIME MICROPHYSICS IMAGERY OVER NORTHEAST
MISSOURI. THAT MEAN CLOUD/STRATUS LAYER FLOW WILL STRENGTHEN
SOME TO OVER 10 KTS THIS MORNING AND SHOULD CLEAR OUT PARTS OF
NORTHWEST IOWA WITH THE LEAST AMOUNT OF STRATUS UPSTREAM. PARTS
OF CENTRAL AND NORTH CENTRAL IOWA THOUGH LIKELY WILL HAVE
STRATUS MUCH OF THE DAY SO HAVE GONE CLOSER TO THE NBM 25TH
PERCENTILE WHERE CLOUDS ARE EXPECTED AND WARMER THAN THE NBM
50TH IN THE SOUTHWEST. IN REALITY, THE TEMPERATURE GRADIENT WILL
LIKELY BE MORE EXTREME THAN THIS. FOG WILL PERSIST OVER
NORTHERN IOWA, PERHAPS INTO THE AFTERNOON AND BY EXTENSION INTO
TONIGHT. THE CURRENT DENSE FOG ADVISORY WILL HAVE MORE UPDATES
AND EXPANSIONS AS WELL AND IT DOES END AT 9 AM. THIS TIMING WILL
NEED TO BE ADJUSTED LONGER IN SOME AREAS.
THE STRATUS STEERING FLOW WILL BECOME SOUTHERLY ON WEDNESDAY AND
INCREASE. A MUCH DRIER BOUNDARY LAYER WILL FOLLOW AND THIS SHOULD
ALLOW TEMPERATURES TO TAKE OFF AND MAKE A RUN AT RECORD HIGHS OVER
CENTRAL AND SOUTHERN IOWA. THE RECORD HIGH AT DES MOINES IS 59 AND
THE CURRENT FORECAST HIGH IS 58. THIS HIGH IS CONSERVATIVE IF
EFFICIENT MIXING THROUGH THE LOW LEVEL INVERSION AS THE LACK OF SNOW
COVER AND A RELATIVELY DRY GROUND AND LOWER DEW POINTS ALL SUGGEST
EFFICIENT HEATING.
WILL END THIS DISCUSSION WITH A BRIEF EXPECTATION WITH THE ACTIVE
WEATHER ARRIVING THURSDAY AND INTO THE WEEKEND. IT IS BECOMING CLEAR
THAT THIS WILL OCCUR IN THREE PHASES. THE FIRST PHASE AND SHORT WAVE
ARRIVE THURSDAY WITH STRONG GULF MOISTURE TRANSPORT NORTH AND
SURFACE LOW PRESSURE PASSING JUST SOUTHEAST OF THE AREA. THIS WILL
BRING RAIN TO SOUTHEAST IOWA BUT THE NORTHWEST SIDE OF THIS
PRECIPITATION SHIELD COULD BE A WINTRY MIX WITH MAINLY SNOW BUT ALSO
PERHAPS A BOUT OF FREEZING RAIN. THE SECOND AND COLDER SYSTEM
ARRIVES LATE FRIDAY THROUGH EARLY SATURDAY. AT THIS TIME, THIS LOOKS
LIKE ACCUMULATING SNOW FOR THE AREA. THIS IS THE PERIOD THAT MODELS
ARE STILL JUGGLING A BIT WITH NORTHERN AND SOUTHERN STREAM SHORT
WAVES CONVERGING OVER THE STATE, WHICH WILL IMPACT THE INTENSITY OF
THIS SYSTEM. THE THIRD PHASE IS EVEN COLDER AIR ARRIVING IN THE WAKE
OF THIS, BUT AT THIS POINT IT IS NOT ARCTIC IN ORIGIN.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1143 AM CST TUE JAN 6 2026
FOG AND STRATUS HAVE REMAINED IN PLACE FOR MOST ALL SITES LONGER
THAN EXPECTED, SO HAVE TRENDED PESSIMISTIC THIS ISSUANCE. LIFR
VSBYS SHOULD LIFT TO MVFR THIS AFTERNOON, AND LIFR CIGS SHOULD
LIFT TO IFR. HOWEVER, CONDITIONS WILL DETERIORATE AFTER 00Z,
BRINGING DENSE FOG AND LOW CIGS AGAIN, MAINLY IN THE NORTHEAST.
SOUTHWEST WINDS WILL INCREASE OVERNIGHT, ENDING FOG AND STRATUS
EARLIER FOR KFOD, KDSM, AND KOTM.
DMX WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR IAZ006-
007-016-017-024>028-035>039-047>050-059>062-073>075-084>086-
095>097.
DISCUSSION...DONAVON
AVIATION...JIMENEZ
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