652
FXUS63 KDMX 021748
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1248 PM CDT SUN AUG 2 2026
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- DRY CONDITIONS PREVAIL THROUGH MONDAY NIGHT WITH HIGHS IN THE LOW
AND MIDDLE 80S. HIGH LEVEL SMOKE ALOFT CONTINUES.
- UP TO 40% CHANCE OF PATCHY FOG MONDAY MORNING.
- WIDESPREAD THUNDERSTORM CHANCES RETURN TUESDAY THROUGH
WEDNESDAY BRINGING WELCOME RAINFALL FOR MANY. WILL NEED TO
MONITOR IF RAINFALL REPEATS OVER THE SAME AREA. A FEW STORMS
MAY BE STRONG TO PERHAPS SEVERE.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 153 AM CDT SUN AUG 2 2026
IT IS A TRANQUIL WEATHER NIGHT OVER THE STATE WITH A JUST A FEW
CLOUDS OVER EASTERN IOWA FLYING SOUTHWESTWARD AROUND THE CONTINUING
TO DEPART LOW PRESSURE, WHICH IS OVER THE LOWER OHIO VALLEY. UPPER
LEVEL WATER VAPOR IMAGERY FROM GOES-EAST SHOWS A WOUND UP,
POSITIVELY TILTED TROUGH IN THE VICINITY OF THE LOW WHILE UPSTREAM
RIDGING BEGINS TO TILT TOWARDS THE REGION. FLOW THROUGHOUT THE
ATMOSPHERE OVER IOWA IS FROM THE NORTH OR NORTHEAST WITH A ZONE OF
HIGH PRESSURE PUSHING INTO THE STATE. THIS AIRMASS IS DRY AND WILL
FOSTER A DAY WITH ABUNDANT SUNSHINE, THOUGH SCATTERED DIURNALLY
DRIVEN CUMULUS MAY POP OVER EASTERN IOWA DUE TO THE CLOSER PROXIMITY
TO THE LOW'S WRAPAROUND MOISTURE. ONE CHALLENGE TO THE FORECAST ARE
THE DEWPOINTS WITH THE INITIAL NATIONAL BLEND OF MODELS SUFFERING
FROM A SEASONAL HIGH BIAS IN THIS DRIER REGIME. HOWEVER, THIS IS
ALSO PEAK EVAPOTRANSPIRATION SEASON, WHICH MAY OFFSET SOME OF THE
LOWER GUIDANCE. FORECAST SOUNDINGS FROM A VARIETY OF MODELS (E.G.
NAM, GFS, HRRR, RAP, NAMNEST) SHOW THE BOUNDARY LAYER BECOMING WELL
MIXED ENTRAINING DRIER AIR TO THE SURFACE LATE IN THE MORNING TO
EARLY EVENING. WHILE THE MIDDLE AND UPPER 50 DEWPOINTS SOME MODELS
PRODUCE SEEMS OUT OF REACH, HAVE BACKED OFF DEWPOINTS A FEW DEGREES
TO THE LOW AND MIDDLE 60S TODAY. TEMPERATURE WISE, CONDITIONS WILL
BE SEASONAL IN THE LOW 80S.
AS HIGH PRESSURE MOVES OFF TO THE EAST TONIGHT, LIGHT WINDS AND A
CLEAR SKY OFFER A SETUP FOR FOG POTENTIAL. LAMP PROBABILITIES ARE
AROUND 20 TO 30% AREAWIDE WHILE HREF IS BETWEEN 20 AND 40%. ANY
PATCHY FOG EARLY MONDAY WILL DISSIPATE AFTER SUNRISE WITH ANOTHER
MOSTLY SUNNY DAY FORECAST. WHILE DEWPOINTS MONDAY WERE ONCE AGAIN
ADJUSTED DOWNWARD WITH SIMILAR THINKING AS ABOVE, THEY WILL BE
HIGHER THAN SUNDAY IN THE MIDDLE AND UPPER 60S DUE TO SOUTHERLY FLOW
AHEAD OF THE ADVANCING TROUGH AND COLD FRONT THAT WILL BE MOVING
OVER THE NORTHERN STATES TOWARDS IOWA.
FOR BOTH TODAY AND MONDAY, HIGH LEVEL SMOKE WILL CONTINUE TO BE
ALOFT WITH THE HRRR AND RAP SHOWING THIS THROUGH THEIR ENTIRE RUNS
ENDING MONDAY WITH THE RRFS SHOWING IT THROUGH TUESDAY AHEAD OF THE
NEARING COLD FRONT.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED AT 244 PM CDT SAT AUG 1 2026
A SEGMENT OF THE UPPER LOW IN CANADA WILL INTENSIFY ALONG THE
NATIONAL BORDER AND TILT NEGATIVELY ACROSS NORTH DAKOTA AND
MINNESOTA. WE'LL SEE THE EFFECTS OF ITS COLD FRONT AS EARLY AS
TUESDAY AFTERNOON, LASTING THROUGH WEDNESDAY. INSTABILITY OVER 1000
J/KG SETS UP IN THE WARM SECTOR, BUT WITH FAVORABLE DEEP-LAYER
SHEAR LAGGING BEHIND THE BOUNDARY. FLOW WILL BE PARALLEL TO THE
BOUNDARY AND PWATS WILL RISE ABOVE 1.5", SO THERE WILL BE HEAVY
RAIN POTENTIAL IN NORTHERN IOWA DUE TO MOISTURE CONTENT AND
TRAINING STORMS. THIS RISK IS CURRENTLY REPRESENTED WITH A
MARGINAL EXCESSIVE RAINFALL OUTLOOK.
IOWA WILL STAY IN CYCLONIC FLOW THROUGH THE REMAINDER OF THE WEEK
WHICH WILL KEEP PRECIPITATION CHANCES AND COOLER TEMPERATURES IN
PLAY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1242 PM CDT SUN AUG 2 2026
MVFR CUMULUS AFFECTING KALO FOR THE NEXT 2-3 HOURS, BUT WILL
LESSEN IN COVERAGE THROUGH THE AFTERNOON. SCT CLOUDS NEAR KOTM
WITH LOWER CONFIDENCE IN MVFR IN THE SHORT TERM. ADDED IN VFR
FOG MENTIONS FOR KOTM IN THE EARLY MORNING HOURS. HIGHER
CONFIDENCE IN MVFR/IFR TO THE EAST OF THE SITE WHERE MORE RAIN
FELL THE PAST FEW DAYS. WILL REFINE IN LATER ISSUANCES. A
SECONDARY TERMINAL TO WATCH FOR A FOG MENTION LATER IS KALO, BUT
CONFIDENCE IS TOO LOW TO ADD FOR NOW. MOISTURE WILL LIFT TO A
LOW CUMULUS DECK THROUGH THE MORNING AND WILL BRING OPPORTUNITY
FOR MVFR CIGS INTERMITTENTLY.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...ANSORGE
LONG TERM...JIMENEZ
AVIATION...JIMENEZ
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