143
FXUS63 KDMX 051114
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
514 AM CST WED NOV 5 2025
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
KEY MESSAGES
- BREEZY CONDITIONS TODAY AND THURSDAY, WITH GUSTS OVER 30 MPH
POSSIBLE BOTH DAYS.
- SCATTERED RAIN CHANCES EAST AND SOUTHEAST THURSDAY NIGHT INTO
FRIDAY MORNING.
- MULTIPLE SYSTEMS MOVING THROUGH FRIDAY INTO SATURDAY, BRINGING
COOLER TEMPERATURES AND POTENTIAL FOR RAIN AND/OR SNOW ON
SATURDAY.
DISCUSSION
ISSUED AT 353 AM CST WED NOV 5 2025
>> WEDNESDAY & THURSDAY WINDS
WE REMAIN ON TRACK FOR GUSTY CONDITIONS THIS MORNING, AS A COLD
FRONT IS PULLED THROUGH IOWA BY A SURFACE LOW CURRENTLY
TRACKING EASTWARD OVER EASTERN MINNESOTA AND WISCONSIN. AS OF
THIS WRITING, THE SURFACE BOUNDARY IS ROUGHLY HALF WAY THROUGH
THE STATE, BISECTING OUR FORECAST AREA. HOWEVER, THE STRONGEST
WINDS ARE SLIGHTLY LAGGING THE SURFACE BOUNDARY, CURRENTLY IN
FAR NORTHWEST IOWA AND SOUTHERN MINNESOTA WHERE PRESSURE
GRADIENTS ARE TIGHTEST. THAT SAID, SPORADIC GUSTS IN THE 20 TO
25 MPH RANGE ARE BEING REPORTED NEARER TO THE BOUNDARY IN
CENTRAL IOWA, JUST NOT CONSISTENTLY. AS THE STRONGER PRESSURE
GRADIENTS AND COLD AIR FILL IN BEHIND THE FRONT THROUGH THE
MORNING, GUSTY WINDS WILL INCREASE AND BECOME MORE CONSISTENT
ACROSS THE AREA. A SLIGHT INCREASE IN COVERAGE OF GUSTY WINDS
MAY ALSO BE SEEN AFTER SUNRISE WHEN ANY REMAINING INVERSIONS MIX
OUT, BUT THE CAA BEHIND THE FRONT SHOULD WORK TO ELIMINATE THE
INVERSIONS BEFORE SUNRISE. WIND GUSTS AROUND 25 TO 35 MPH WILL
BE COMMON THROUGH THE MORNING, WITH OCCASIONAL GUSTS EXCEEDING
35 MPH, ESPECIALLY IN NORTHERN AND NORTHEASTERN IOWA. OUR WINDS
TODAY WILL BE STRONGEST AROUND MID- TO LATE-MORNING, THEN
DECREASE INTO THE AFTERNOON HOURS WHEN PRESSURE GRADIENTS WEAKEN
AND SURFACE HIGH PRESSURE MOVES IN OVERHEAD.
BREEZY CONDITIONS DEVELOP AGAIN ON THURSDAY AS LOW PRESSURE MOVES
INTO THE AREA, BUT WILL HAVE A LITTLE BIT MORE WORKING AGAINST THEM
COMPARED TO TODAY. (1) FLOW WILL BE SOUTHERLY, PUTTING US IN A WAA
REGIME, (2) SURFACE PRESSURE WILL BE FALLING WITH THE LOW PRESSURE
MOVING IN AND (3) CLOUD COVER WILL BE FILLING IN OVERHEAD. ALL OF
THESE THINGS LIMIT DOWNWARD MOMENTUM TRANSFER, AND THEREFORE MAKE IT
HARDER TO GET STRONG WINDS AT THE SURFACE. THAT SAID, THE PRESSURE
GRADIENT OVERHEAD WILL BE STRONGER THAN TODAY'S, HELPING TO OFFSET
THE POOR DOWNWARD MOMENTUM TRANSFER. LIKEWISE, IF WE CAN STILL MIX
OUT BENEATH THE CLOUD COVER, 30 TO 40+ KT WINDS WILL BE WAITING AT
THE TOP OF THE BOUNDARY LAYER. GIVEN ALL THIS, GOING FORECAST HAS
ONLY SLIGHTLY WEAKER WIND GUSTS COMPARED TO TODAY. WIDESPREAD WIND
GUSTS OF 25 TO 30 MPH ARE FORECAST, WITH A SMALL AREA IN NORTHERN
IOWA NEARING 35 MPH. THESE WINDS WILL PERSIST THROUGH THE DAY, THEN
DIMINISH AFTER SUNSET.
>> THURSDAY NIGHT/FRIDAY MORNING RAIN CHANCES
FINALLY, A SUBTLE TROUGH ASSOCIATED WITH THE SYSTEM BRINGING GUSTY
WINDS ON THURSDAY WILL PASS THROUGH THE STATE THURSDAY NIGHT INTO
FRIDAY MORNING. INCREASING GULF MOISTURE AND UPPER LEVEL PACIFIC
MOISTURE WILL PHASE OVER EASTERN IOWA, ATTEMPTING TO SATURATE AN
OTHERWISE DRY VERTICAL PROFILE IN IOWA. EARLY CAM GUIDANCE SHOWS
THAT LIFT ALONG THE TROUGH DOES PRODUCE SCATTERED SHOWERS OVER THE
EASTERN AND SOUTHEASTERN PORTIONS OF THE AREA ON THURSDAY
NIGHT. MODEL SOUNDINGS LOOK A BIT MORE PESSIMISTIC FOR RAIN
CHANCES IN OUR AREA, WITH PROFILES NEVER REALLY REACHING
SATURATION THROUGH THE ENTIRE COLUMN. HOWEVER, WITH THE TWO
HEALTHY MOISTURE STREAMS AND PWATS OVER AN INCH (CLIMO FOR THIS
TIME OF YEAR IS AROUND A HALF INCH), TOUGH TO ARGUE AGAINST AT
LEAST SOME LIGHT RAIN OCCURRING. LOCATIONS FARTHER EAST IN THE
AREA WILL BE MOST FAVORABLE FOR RAIN, AS SATURATION CONTINUES TO
IMPROVE THE FARTHER EAST YOU GO. FORTUNATELY, WARM TEMPERATURES
KEEP EVERYTHING AS RAIN, SOMETHING THAT CAN'T BE SAID FOR THE
NEXT SYSTEM WE HAVE TO TALK ABOUT...
>> WEEKEND RAIN/SNOW POTENTIAL
OKAY, IF YOU'VE MADE IT THIS FAR, CONGRATS! THIS IS WHERE IT GETS
FUN. WE ARE CONTINUING TO MONITOR A QUICK MOVING SYSTEM THAT WILL
MOVE THROUGH THE AREA ON SATURDAY, BRINGING MUCH COLDER AIR AND MORE
PRECIPITATION. THIS "SYSTEM" WILL ACTUALLY BE A COMBINATION OF TWO
WAVES PASSING THROUGH THE OVERALL TROUGHING PATTERN THAT WILL SET UP
INTO THE WEEKEND. THE FIRST WAVE WILL BE A SHORTWAVE DROPPING
SOUTHEASTWARD OUT OF CANADA AND INTO IOWA, AND THE SECOND WILL BE A
MORE PROMINENT WAVE OSCILLATING THROUGH THE LARGE SCALE TROUGH.
DEPENDING ON THE SOLUTION YOU PREFER, THESE TWO WAVES WILL
EITHER PHASE WITH EACH OTHER OR REMAIN STAGGERED, BOTH BRINGING
SLIGHTLY DIFFERENT OUTCOMES.
IN BOTH SCENARIOS, THE FIRST WAVE PASSES THROUGH IOWA,
DEVELOPING A SURFACE LOW ALONG ALONG OUR SOUTHERN BORDER.
PRECIPITATION FORMS IN THE DEFORMATION ZONE ON THE NORTHERN
FLANK OF THE SURFACE LOW, PRODUCING PRECIPITATION OVER IOWA.
THIS FIRST WAVE IS THEN FOLLOWED BY A SECOND, MORE PROMINENT
WAVE WHICH BRINGS MUCH COLDER TEMPERATURES DOWN WITH IT. WHERE
THE TWO SCENARIOS DIFFER IS IN THE PROGRESSION OF THESE TWO
WAVES. THE LESS INTERESTING SCENARIO, BEING CHAMPIONED BY THE
ECMWF, HAS A SLIGHTLY FASTER PROGRESSION OF THE FIRST WAVE AND
MUCH SLOWER PROGRESSION OF THE SECOND. THIS KEEPS TEMPERATURES
WARMER, RESULTING IN MOSTLY RAIN FALLING OVER THE AREA AND
OCCASIONAL SNOW MIXED IN OVER FAR NORTHERN IOWA ALONG THE
IOWA/MINNESOTA BORDER. IN THE MORE INTERESTING SCENARIO, BEING
CHAMPIONED BY THE GFS, THE FIRST WAVE IS A FEW HOURS SLOWER AND
SECOND WAVE MUCH FASTER, CAUSING THE TWO WAVES TO PHASE WITH
EACH OTHER. THIS INTERACTION FUNNELS COLDER TEMPERATURES IN
SOONER, CAUSING MORE PRECIPITATION TO FALL AS SNOW IN A SWATH
OVER THE NORTHERN HALF OF THE STATE ON SATURDAY.
WHILE IT'S TOUGH TO SAY WHICH OF THE ABOVE SCENARIOS WILL WIN
OUT, THERE HAS CERTAINLY BEEN A SOUTHERLY TREND IN GUIDANCE WITH
THE TRACK OF THE SURFACE LOW AND PRECIPITATION. DETERMINISTIC
MODELS ARE ALL IN FAIRLY GOOD AGREEMENT THAT THE TRACK OF THE
LOW WILL BE ALONG THE IOWA/MISSOURI BORDER, ALBEIT AT SLIGHTLY
DIFFERENT TIMES. THIS CURRENT TRACK WOULD PUT MUCH OF THE STATE
IN THE DEFORMATION ZONE AND PRECIPITATION. ENSEMBLE GUIDANCE IS
ECHOING THIS, WITH NBM PRECIPITATION PROBABILITIES SHOWING A
WIDESPREAD 60 TO 65% CHANCE OF PRECIPITATION NORTH OF INTERSTATE
80 ON SATURDAY. WHERE THE FORECAST CHALLENGE LIES IS IN THE
TEMPERATURES AND RESULTING PRECIPITATION TYPE. WITH THE SOUTHERN
TRACK OF THE LOW, IT SEEMS INCREASINGLY LIKELY WE WILL AT LEAST
SEE OCCASIONAL SNOW MIXED IN WITH RAIN OVER NORTHERN IOWA. THE LREF
GRAND ENSEMBLE PROBABILITIES (WHICH COMBINE THE ECWMF-BASED
ENSEMBLE, THE GFS-BASED ENSEMBLE AND CANADIAN-BASED ENSEMBLE)
SHOW A ROUGHLY 50 TO 60% CHANCE OF MEASURABLE SNOW NORTH OF
INTERSTATE 80, WITH SLIGHTLY HIGHER PROBABILITIES IN NORTHWEST
IOWA. THE NBM PROBABILITIES FOR MEASURABLE SNOW ARE SLIGHTLY
LOWER, AROUND 40 TO 45%. OF COURSE, ONLY ONE SOLUTION WILL
EVENTUALLY OCCUR, SO WE WILL BE MONITORING BOTH DETERMINISTIC
AND ENSEMBLE GUIDANCE THROUGH THE COMING DAYS FOR MORE
INFORMATION ON WHAT COULD BE THE FIRST SNOWFALL OF THE SEASON.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 510 AM CST WED NOV 5 2025
GUSTY NORTHWESTERLY WINDS ARE EXPECTED THROUGH THIS MORNING,
WITH GUSTS AROUND 25 TO 35 KTS POSSIBLE. WINDS WILL BE STRONGEST
THROUGH THE MORNING, BEFORE DIMINISHING INTO THE AFTERNOON. AN
AREA OF STRATUS IS ALSO DROPPING SOUTHWARD TOWARD THE AREA,
BRINGING MVFR CEILINGS TO KMCW AND POTENTIALLY KFOD. HOWEVER,
THESE CLOUDS SHOULD BE LIFTING AS IT DROPS SOUTHWARD. OTHERWISE,
SKIES CLEAR OUT THIS AFTERNOON AS WELL.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...DODSON
AVIATION...DODSON
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