602
FXUS63 KDMX 121931
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
231 PM CDT SUN JUL 12 2026
KEY MESSAGES
- WARM AND DRY CONDITIONS TODAY THROUGH MID-WEEK. HEAT INDICES
IN THE 90S TO NEAR 100F.
- ISOLATED FOG POSSIBLE AGAIN TONIGHT, MAINLY OVER SOUTHEAST
IOWA.
- WARM TEMPERATURES LAST THROUGH THE END OF THE WORK WEEK,
ALTHOUGH RAIN MAY RETURN BY THE WEEKEND.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED AT 228 PM CDT SUN JUL 12 2026
WARM, SUMMER-LIKE CONDITIONS ARE IN PLACE OVER ALL OF IOWA TODAY.
WINDS ARE LIGHT, SKIES ARE CLEAR AND TEMPERATURES ARE WARM THANKS TO
THE HIGH PRESSURE RIDGE NOW ESTABLISHING ITSELF OVERHEAD. EAST
SOUTHEASTERLY FLOW YESTERDAY AND TODAY HAS BROUGHT DRIER LOW-LEVEL
AIR INTO THE AREA, KEEPING DEWPOINTS A FEW DEGREES LOWER TODAY THAN
YESTERDAY, ALBEIT STILL MOIST IN THE LOW TO MID 60S. TEMPERATURES
ARE GENERALLY ON PACE WITH WHERE THEY WERE THIS TIME YESTERDAY, BUT
WITH SLIGHTLY DRIER CONDITIONS, HIGHS WILL LIKELY WARM A FEW DEGREES
MORE TODAY, REACHING THE MID TO UPPER 80S. WITH THE SURFACE HIGH
FIRMLY ENTRENCHED IN IOWA TONIGHT, WINDS WILL GO CALM AND SKIES WILL
CLEAR, LEADING TO YET ANOTHER NIGHT OF PRIME RADIATIONAL COOLING.
THIS OPENS UP POTENTIAL FOR MORE FOG DEVELOPMENT, BUT THE DRIER
DEWPOINTS AND MARGINALLY WARMER AIRMASS WILL MEAN MORE COOLING WILL
BE NEEDED TO REACH SATURATION TONIGHT COMPARED TO PREVIOUS. STILL,
ISOLATED POCKETS OF FOG WILL BE POSSIBLE PRIOR TO SUNRISE EARLY
MONDAY MORNING AS COLD AIR POOLS IN LOW LYING AREAS AND LOCALIZED
SATURATION OCCURS. WIDESPREAD FOG APPEARS UNLIKELY AT THIS TIME.
THE FORECAST GENERALLY REMAINS STATUS QUO THROUGH AT LEAST THE FIRST
HALF OF THE WORK WEEK. THE WARMEST 850 MB TEMPERATURES ARE EXPECTED
TO ROUND THE 850 MB RIDGE SITTING DIRECTLY OVERHEAD, KEEPING THE
WARMEST TEMPERATURES TO OUR NORTH AND WEST. WITH NO SIGNIFICANT
CHANGES IN AIR MASS IN IOWA, SURFACE HEATING AND THERMAL MIXING WILL
DRIVE TEMPERATURES FROM DAY-TO-DAY, SEEING A COUPLE DEGREE INCREASE
EACH DAY. THIS WILL PUT HIGHS IN THE UPPER 80S TO LOW 90S MONDAY,
THEN GENERALLY THE LOW 90S ON TUESDAY, THEN INCREASING WITH EACH DAY
THROUGH MID-WEEK. ASIDE FROM THE INITIAL DRY PUNCH YESTERDAY,
THE MOISTURE ALSO DOESN'T SEE SIGNIFICANT DAY-TO-DAY CHANGE, AT
LEAST THROUGH ADVECTIVE COMPONENTS. EVAPOTRANSPIRATION AND WET
SOILS THROUGHOUT THE CORN BELT WILL CONTRIBUTE MOISTURE TO THE
SURFACE LAYER EACH DAY, PEAKING AROUND MID-MORNING THEN FALLING
OFF STEADILY AS THE BOUNDARY LAYER MIXES INTO THE AFTERNOON.
WITH SURFACE DEWPOINTS REMAINING STEADY, IF NOT SLIGHTLY
INCREASING, THROUGH THE WEEK AND HIGH TEMPERATURES FOLLOWING
SUIT, EXPECTING HEAT INDICES TO CLIMB INTO THE UPPER 90S TO NEAR
100F. FORTUNATELY, IT LOOKS LIKELY WE WILL STAY BELOW OUR 105F
HEAT ADVISORY CRITERIA THROUGH THE FIRST HALF OF THE WEEK, AS
EVEN IF DEWPOINTS END UP HIGHER THAN ANTICIPATED, AMBIENT
TEMPERATURES WON'T BE AS WARM, AND VICE VERSA. THEREFORE, NO
PLANS FOR HEAT HEADLINES AT THIS TIME.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
ISSUED AT 228 PM CDT SUN JUL 12 2026
A CANADIAN LONG WAVE TROUGH WILL DIG SOUTHEASTWARD INTO THE
NORTHEASTERN CONUS THROUGH MID- TO LATE- WEEK, WHICH ATTEMPTS TO
SHUNT THE 500 MB RIDGE OVERHEAD BACK TO THE WEST. AS THIS OCCURS,
THE SURFACE HIGH PRESSURE WILL BEGIN TO WEAKEN, TRANSITIONING US TO
A MORE TRANSIENT SURFACE PATTERN OVER IOWA. THIS INCREASES THE
SPREAD IN TEMPERATURE SOLUTIONS AMONG DETERMINISTIC AND ENSEMBLE
GUIDANCE THROUGH THE END OF THE WEEK. THE GENERAL TREND SEEMS TO BE
CONTINUED WARMING INTO THE WEEKEND, ALTHOUGH NBM MAY BE RUNNING TOO
HOT WITH FORECAST HIGHS IN THE MID 90S AND DEWPOINTS IN THE 60S.
SHOULD DEWPOINTS INCREASE INTO THE 70S, HIGHS WOULD LIKELY BE CLOSER
TO THE LOW 90S. ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST TO
ACCOUNT FOR THIS, BUT WILL NEED TO CONTINUE TO MONITOR TRENDS.
IN ADDITION TO TEMPERATURES, THE WEAKENING HIGH AND INCREASED
MOISTURE THURSDAY INTO FRIDAY MAY BRING BACK RAIN CHANCES TO THE
STATE. THIS IS A LOW CONFIDENCE SCENARIO, ESPECIALLY WITH THE
LATE WEEK PATTERN STILL IN FLUX, SO THE FORECAST REMAINS DRY AT
THIS TIME. SEVERE CHANCES WILL BE BETTER ASSESSED IN THE COMING
DAYS, BUT WEAK FLOW SHOULD HELP MITIGATE SEVERE CHANCES THROUGH
THIS PERIOD.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1217 PM CDT SUN JUL 12 2026
VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS PREVAIL THROUGH
MUCH OF THE PERIOD. WITH LITTLE CHANGE IN CONDITIONS TONIGHT,
ISOLATED FOG MAY ONCE AGAIN DEVELOP. HIGHEST CONFIDENCE FOR FOG
MONDAY MORNING IS OVER SOUTHEAST IOWA (KOTM), WHERE WINDS ARE
EXPECTED TO BE LIGHTEST/CALM.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DODSON
LONG TERM...DODSON
AVIATION...DODSON
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