621
FXUS63 KDMX 110806
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
306 AM CDT SAT JUL 11 2026
KEY MESSAGES
- AREAS OF FOG WILL PERSIST THIS MORNING WITH VISIBILITY BELOW
ONE MILE AT TIMES.
- BUILDING HIGH PRESSURE ALOFT AND AT THE SFC WILL RESULT IN DRY
CONDITIONS FOR AT LEAST THE NEXT SEVERAL DAYS.
- SEASONAL MID JULY TEMPERATURES /HIGHS IN THE 80S/ WILL OCCUR
TODAY AND SUNDAY, WITH A SLIGHT WARMING TREND BY MID-WEEK
/UPPER 80S TO LOWER 90S/. WITH A EASTERLY SFC WIND, DEWPOINT
TEMPERATURES WILL BE MODEST, ALTHOUGH WILL NEED TO WATCH THE
CONTRIBUTION FROM EVAPOTRANSPIRATION.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 255 AM CDT SAT JUL 11 2026
THE SYNOPTIC PATTERN IN THE SHORT TERM WILL BE DOMINATED BY
RISING 500MB HEIGHTS ACROSS THE PLAINS AND MIDWEST, WITH H5 HEIGHTS
IN THE 594-597 DAM RANGE BY 00Z MONDAY, PRETTY IMPRESSIVE. AT
THE SFC THE GREAT LAKES HIGH IS EXPECTED TO EXPAND WESTWARD,
YIELDING GENERALLY AN EASTERLY COMPONENT TO THE SFC WIND. THIS
WILL HAVE SOME IMPACT ON TEMPERATURES AND MOISTURE.
TODAY...AREAS OF FOG WILL BE THE INITIAL CONCERN THIS MORNING. AS
HAS BEEN DISCUSSED RECENTLY, A VERY DIFFUSE SFC PATTERN WITH NEARLY
CALM WINDS, COMBINED WITH CLEARING SKIES AND RESIDUAL LOW LEVEL
MOISTURE HAS RESULTED IN A FAVORABLE RADITIONAL FOG SETUP. BASED ON
THE DEPTH OF MOISTURE IN MODEL SOUNDINGS, FEEL THE FOG IS RATHER
SHALLOW IN DEPTH. NONETHELESS, SEEING A FEW OBSERVATION SITES
DROP FROM 1/2SM TO 1/4SM AS OF 3AM, MAINLY ACROSS NORTHERN AND
WESTERN IA, WHERE SKIES HAVE CLEARED. WE'LL BE MONITORING IF THE
FOG BECOMES WIDESPREAD AND DENSE ENOUGH TO WARRANT A DENSE FOG
ADVISORY. EXPECT THIS FOG TO CONTINUE THROUGH THE EARLY MORNING
HOURS BEFORE GRADUALLY DISSIPATING.
OTHERWISE, EXPECTING SKIES TO BECOME PARTLY TO MOSTLY SUNNY TODAY AS
BROAD SCALE SUBSIDENCE OVERSPREADS THE AREA PER RISING H5 HEIGHTS. A
FEW CAMS TRY TO POP OR ROGUE SHOWER OVER THE WEST IN VICINITY OF
THE DEEPER LOW LEVEL MOISTURE. WITH WEAK LIFT AND SOUNDING
SHOWING A MODEST CAP, WILL LEAVE THE FORECAST DRY FOR NOW.
LITTLE CHANGE IN THE LOW LEVEL THERMAL PROFILE, WITH 850MB TEMPS
HOVERING AROUND +16C TO +18C. THIS WILL RESULT IN HIGH
TEMPERATURES IN THE MID/UPPER 80S, GENERALLY A LOW SPREAD IN THE
PROBABILISTIC GUIDANCE. WITH THE LIGHT E/NE SFC WINDS, THE
MODELS ARE TRYING TO ADVECT IN A DRIER LOW LEVEL AIRMASS. IN
FACT THE RAP/HRRR ARE SHOWING SFC TDS FALLING INTO THE UPPER 50S
OR LOWER 60S IN SOME LOCALES. THE QUESTION IS HOW MUCH WILL
EVAPOTRANSPIRATION OR ET /NOW PEAKING AS CORN IS NEARING
TASSELING/ OFFSET THIS DRIER AIRFLOW? THIS WILL IMPACT NOT ONLY
TDS BUT ALSO HEAT INDICES TODAY AND SUNDAY, BUT ALSO INTO NEXT
WEEK. FOR NOW, KEPT TDS IN THE MIDDLE OF GUIDANCE ENVELOP /MID
60S/ FOR NOW, BUT TODAY WILL BE A GOOD BENCHMARK.
LITTLE CHANGE IN THE PATTERN SATURDAY NIGHT INTO SUNDAY. PATCHY
FOG IS POSSIBLE AGAIN TONIGHT, BUT WITH DRIER TDS, FEEL THE
THREAT IS LOWER. MOSTLY SUNNY ON SUNDAY, WITH TEMPERATURES
TRENDING UP PERHAPS A DEGREE OR TWO.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
ISSUED AT 237 PM CDT FRI JUL 10 2026
DRY AND INCREASINGLY WARM CONDITIONS ARE FORECAST FROM SUNDAY
THROUGH MUCH OF NEXT WEEK AS AN UPPER RIDGE BUILDS AND TRACKS
EASTWARD THROUGH AT LEAST MID WEEK. HIGH PRESSURE AT THE SURFACE
WILL KEEP WINDS LIGHT AND SKIES MAINLY CLEAR OUTSIDE OF SOME
DIURNAL CUMULUS AT TIMES. SOUTHERLY FLOW STARTS TO RETURN EARLY
IN THE WORK WEEK LEADING TO WARMING TEMPERATURES IN THE UPPER
80S TO LOW 90S TUESDAY AND BEYOND WITH HEAT INDICES TOPPING OUT
AROUND THE MID TO OCCASIONALLY UPPER 90S AT TIMES. CERTAINLY
WARM, BUT LOOKING TO BE BELOW HEAT HEADLINE CRITERIA.
PRECIPITATION CHANCES THEN RETURN LATER IN THE WEEK IN AT LEAST
THE EAST INTO FRIDAY, THOUGH AT THIS TIME RANGE THERE IS STILL A
FAIR AMOUNT OF MODEL SPREAD AND PLENTY OF TIME TO REFINE THE
FORECAST.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1054 PM CDT FRI JUL 10 2026
MAIN AVIATION CHALLENGE THIS PERIOD IS FOG POTENTIAL TOWARD
SUNRISE, WHICH HAS SHOWN AN INCREASING TREND IN OCCURRENCE AND
RESTRICTIONS. HAVE FOCUSED LOWEST RESTRICTIONS, DOWN TO IFR, AT
FOD AND MCW. LIFR RESTRICTIONS ARE POSSIBLE WITH A 30% CHANCE AT
BOTH OF THESE TERMINALS. MVFR/VFR FOG IS FORECAST AT ALO AND
DSM. THE FOG WILL DISSIPATE A FEW HOURS AFTER SUNRISE WITH DIURNAL
CUMULUS POSSIBLE WITH CEILINGS LIFTING FROM BETWEEN FL020-030 UP
TO AROUND FL050. THE COVERAGE THOUGH IS EXPECTED TO KEEP
CONDITIONS VFR AFTER THE FOG DISSIPATES THROUGH THE END OF THE
PERIOD.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...FOWLE
LONG TERM...05
AVIATION...ANSORGE
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