344
FXUS63 KDMX 191721
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1221 PM CDT MON OCT 19 2026
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- SLIGHTLY COOLER TODAY FOLLOWED BY A WARMING TREND THROUGH THE
WEEK. HIGH TEMPERATURES WILL REMAIN ABOVE SEASONAL NORMALS.
- THE FORECAST IS DRY THROUGH THE WORK WEEK, WITH RAIN CHANCES
RETURNING SOMETIME NEXT WEEKEND.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED AT 247 AM CDT MON OCT 19 2026
THE TRANSITION TO WEAK SOUTHWEST FLOW ALOFT HAS BEGUN AND THIS HAS
LED TO HIGH LEVEL CIRRUS ARRIVING INTO THE MIDWEST. A SLIGHT COOLING
IN THE THERMAL PROFILE AT AND BELOW 850 MB HAS OCCURRED OVER THE
PAST 24 HRS AS THE UPPER LEVEL RIDGING WAS FLATTENED PRIOR DURING
THE TRANSITION. A WEAKENING OF THE PRESSURE GRADIENT AND MIXED LAYER
WINDS WILL ALSO BE NOTICEABLE TODAY. THE NET RESULT OF ALL OF THIS IS
A FEW PASSING CLOUDS AND SLIGHTLY COOLER HIGH TEMPERATURES. UPPER
LOW PRESSURE DIVING SOUTH ALONG THE PACIFIC COAST ALONG WITH SUB-
TROPICAL HIGH PRESSURE BUILDING INTO SOUTHERN TEXAS, WILL COMBINE TO
START TO BUILD UPPER RIDGING TO THE WEST OF THE STATE ON TUESDAY
WITH MID-LEVEL DIFFLUENCE OVER IOWA. MIXED LAYER WINDS WILL INCREASE
ON TUESDAY WITH DIURNAL WIND GUSTS OF 15 TO 20 MPH POSSIBLE. HIGH
TEMPERATURES ON TUESDAY WILL BE A FEW DEGREES WARMER THAT TODAY WITH
READINGS IN THE 60S TO NEAR 70.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED AT 103 PM CDT SUN OCT 18 2026
BETWEEN WEDNESDAY AND WEDNESDAY NIGHT THE WEAKENED 500 MB
TROUGH AXIS WILL FINALLY CROSS IOWA, BRINGING SOMEWHAT THICKER
MID/HIGH LEVEL CLOUDS. HOWEVER, THE TROUGH WILL BE LARGELY
WASHED OUT BY THAT TIME AND A DEEP NEAR-SURFACE DRY LAYER WILL
PERSIST, ONCE AGAIN REDUCING ANY RAIN CHANCES. THEREAFTER, A
HIGH-AMPLITUDE RIDGING PATTERN WILL BUILD ACROSS THE CENTRAL
U.S., WITH THE AXIS STRETCHING ALL THE WAY FROM MEXICO UP TO
HUDSON BAY BY THURSDAY EVENING. THIS WILL MAINTAIN DRY AND
NOTABLY WARMER WEATHER AT THE END OF THE WORK WEEK. BOTH
THURSDAY AND FRIDAY HIGH TEMPERATURES WILL LIKELY RANGE IN THE
MID TO UPPER 70S, AND A FEW AREAS COULD EVEN TOUCH 80 DEGREES.
BY FRIDAY, EVEN AS THE 500 MB RIDGE AXIS MOVES OVER IOWA, A
DEEP TROUGH WILL BUILD OVER THE WESTERN U.S. AND SUBSEQUENTLY
SLIDE NORTHEASTWARD INTO THE UPPER MIDWEST, SHUNTING THE
PRECEDING RIDGE SOUTHEASTWARD AND BRINGING A RETURN OF RAIN
CHANCES FOLLOWED EVENTUALLY BY A SURFACE TROUGH/COOL FRONT
THROUGH IOWA. WHILE THIS GENERAL SCENARIO IS LIKELY TO OCCUR,
LONG-RANGE MODELS STILL VARY CONSIDERABLY IN THE DETAILS OF THE
EVOLUTION, TIMING AND MAGNITUDE OF ANY RAIN CHANCES, STRENGTH
OF THE SURFACE TROUGH, ETC. AS SUCH, PERSISTENT LOW (20-30%)
RAIN CHANCES ARE FORECAST NEXT WEEKEND BUT IT IS LIKELY THESE
WILL EVENTUALLY NARROW TO A SHORTER PERIOD OF HIGHER POPS AS
CONFIDENCE IN TIMING INCREASES LATER THIS WEEK.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1215 PM CDT MON OCT 19 2026
VFR CONDITIONS PREVAIL WITH LIGHT WINDS OUT OF THE SOUTH TO
SOUTHEAST. OCCASIONAL HIGH CLOUDS WILL PASS THROUGH DURING THE
DAY TODAY, WITH SKIES CLEARING OUT OVERNIGHT. THERE IS SOME
SIGNAL FOR PATCHY, SHALLOW FOG EARLY TOMORROW MORNING (9Z TO
12Z), MAINLY NEAR KMCW, BUT PROBABILITIES ARE TOO LOW TO INCLUDE
IN TAFS AT THIS TIME.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DONAVON
LONG TERM...LEE
AVIATION...DODSON
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