309
FXUS63 KDMX 121946
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
246 PM CDT FRI SEP 12 2025
KEY MESSAGES
- SCATTERED SHOWERS AND A FEW RUMBLES OF THUNDER THIS AFTERNOON
AND EVENING. (UP TO 50% CHANCE) RAINFALL AMOUNTS UNDER A TENTH
OF AN INCH.
- HEAT IN STORE UNTIL MIDWEEK NEXT WEEK, THE HOTTEST BEING
SATURDAY. HIGHS ON SATURDAY IN THE MID 90S; HIGHS BEYOND IN
THE LOW 90S.
- <25% CHANCE OF RAIN SUNDAY NIGHT INTO MONDAY. BETTER RAIN
CHANCES ARRIVE WEDNESDAY AND BEYOND.
DISCUSSION
ISSUED AT 241 PM CDT FRI SEP 12 2025
UPPER-LEVEL RIDGING CONTINUES TO USHER IN UNSEASONABLY WARM AIR
TODAY. A SHORTWAVE IS MOVING ACROSS THE TOP OF THE RIDGE THIS
AFTERNOON WITH THETA-E ADVECTION PROVIDING ENOUGH MOISTURE TO
FIRE OFF SOME SHOWERS AND STORMS ALONG THE MOISTURE AXIS. WARMER
AIR IS YET TO COME UPSTREAM, NOTICING THE 22C 850MB
TEMPERATURES IN THE 12Z RAOBS. THESE VALUES SIT AT THE 90TH
PERCENTILE FOR THE CENTRAL PLAINS SITES OBSERVING THESE
TEMPERATURES (SITES SUCH AS OUN), AND 22C WOULD EXCEED THE 90TH
PERCENTILE AT OAX. ALL THIS TO SAY, WE'LL BE APPROACHING RECORD
HIGHS TOMORROW IN CENTRAL IOWA. HIGHS TOMORROW IN THE SOUTH WILL
REACH THE MID 90S UNDER A MIX OF SUN AND CLOUDS. HEAT INDICES
WILL REMAIN CLOSE TO ACTUAL TEMPERATURES DUE TO THE LOWER DEW
POINTS. NONETHELESS, IT WILL BE IMPORTANT TO STAY HYDRATED AND
COOL AMIDST A LATE SEASON ROUND OF HEAT.
THE 850MB HIGH WILL REMAIN CENTERED OVER THE OZARKS/MID SOUTH,
LIMITING THE AMOUNT OF GULF MOISTURE THIS WEEKEND AND STALLING IT
INTO NEXT WEEK. THE LACK OF LOW-LEVEL MOISTURE ALREADY SHOWS TODAY
WITH CONVECTIVE PRECIP LOADING JUST MANAGING TO GET SOME SHOWERS OUT
OF THE 8KFT CLOUD BASES. THE THETA-E AXIS WILL PIVOT AROUND
NORTHEAST IOWA THROUGH THE NIGHT AND INTO SATURDAY. DEEPER
SATURATION LOOKS TO BE FAR ENOUGH EAST TO SPARE OUR AREA FROM MORE
RAIN, BUT CLOUD COVER MAY LINGER IN NORTHEAST IOWA. THEREFORE, HIGH
TEMPERATURES HAVE BEEN ADJUSTED SATURDAY, WITH PARTS OF NORTHEAST
IOWA BEING HELD CLOSER TO 90 DEGREES. SUNDAY WILL BE SIMILAR IN
HIGHS.
THE EXTENDED FORECAST REMAINS WARM WITH HIGHS IN THE 90S. A COLORADO
LOW WILL HINDER WAA AND MOISTURE TRANSPORT INTO THE UPPER MIDWEST AT
LEAST UNTIL WEDNESDAY, MEANING THAT HIGH TEMPERATURES WILL STAY
CLOSER TO 90 DEGREES. THE NEXT CLOSEST ROUND OF PRECIPITATION WILL
BE SUNDAY NIGHT AS A NEGATIVELY TILTED TROUGH SWINGS INTO THE
REGION. CONFIDENCE IS LOW IN THIS RAIN REACHING CENTRAL IOWA DUE
TO MOISTURE ISSUES MENTIONED EARLIER (<25% CHANCE). A CAPE
GRADIENT PARKS OVER EASTERN IOWA WHICH MAY BRING ENOUGH LIFT FOR
SHOWERS AND STORMS IN THE PEAK MIXING HOURS IN THE LATE
AFTERNOON, BUT CONFIDENCE IS LOW (<20%) SINCE HIGH PRESSURE
HOLDS THE DRY AIR. FINALLY, A LONG WAVE TROUGH FROM SOUTHWEST
CANADA INVADES THE UPPER RIDGE, OPENING THE REGION UP TO RAIN
CHANCES AND COOLER WEATHER IN THE SECOND HALF OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1241 PM CDT FRI SEP 12 2025
VFR CONDITIONS TO PREVAIL. SHOWERS WITH SOME THUNDERSTORMS WILL
REMAIN POSSIBLE FOR CENTRAL AND NORTHERN SITES OVER THE NEXT 6
HOURS. THUNDERSTORM POTENTIAL HAS CONTINUED TO TREND DOWN AND
CIGS ARE HIGH. HAVE ONLY COVERED CHANCES AT KFOD AND KDSM FOR
NOW AS UNCERTAINTY REMAINS IN COVERAGE FURTHER EAST (AFFECTING
KALO AND KMCW)
LLWS WILL BE POSSIBLE AT KDSM TONIGHT, THEN SOUTHWEST WINDS PICK
UP AFTER 12Z FOR ALL SITES, BUT NOT AS GUSTY AS TODAY.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...JIMENEZ
AVIATION...JIMENEZ
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