619
FXUS63 KDMX 251959
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
259 PM CDT Wed Sep 25 2024

.KEY MESSAGES...

- Above normal temperatures in the upper 70s to mid 80s continue
  through the weekend.
- Late week precipitation chances continue to dwindle with dry
  forecast prevailing into next week.
- Cooler, fall temperatures incoming next week.

&&

.DISCUSSION...
Issued at 254 PM CDT Wed Sep 25 2024

Upper level pattern characterized by a closed low over the mid
Mississippi Valley, a ridge over much of the western into central
U.S., and Hurricane Helene in the Gulf of Mexico. The ridge axis
moves over the upper Midwest tomorrow with high pressure continuing
to dominate the forecast in Iowa at the surface through the end of
the week and even into the weekend north/northwest. What does this
mean for our weather? Well, the dry, pleasant, albeit warmer than
normal conditions are here to stay through the rest of the week and
into the weekend. (Note, normal temperatures for this time of year
are in the low to mid 70s for highs, and mid 40s to low 50s for low
temperatures.) As noted in the previous discussion, the
precipitation chances associated with the remnants of Hurricane
Helene as the system merges with the cutoff low over the Ohio-
Tennessee Valley Region continue to dwindle with a completely
dry forecast in the area through the next 7 days as ensembles
and deterministic guidance come into better agreement that
precipitation chances remain to the east/southeast of the area.
We will see some increasing cloud cover associated with the
system Thursday night through Friday night mainly south to the
southeast half of the area which may help keep temperatures a
couple degrees cooler in the south. Otherwise, high temperatures
in the upper 70s to mid 80s persist through the weekend and to
start next week. Tomorrow/Thursday will likely see another round
of diurnal cumulus similar to this afternoon with another
chance for patchy fog to start the day. Overall confidence in
fog impacts remain low with hi-res guidance suggesting only as
high as a 35% probability that visibility will be less than 5
miles in the northeast early Thursday morning and less than 15%
anywhere that visibility will be less than 1 mile. Would expect
any fog to be our typical foggy spots like river valleys, if
any.

As we get into next week, a stark change is expected as a dry cold
front brings fall temperatures to the area on Tuesday with highs
only in the 60s, a 10-15 degree temperature drop from Monday. The
fall temperatures then look to persist as a Canadian high pressure
moves into the area keeping temperatures cooler, but then also
conditions dry.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1245 PM CDT Wed Sep 25 2024

VFR conditions ongoing and expected to continue through the TAF
period with just some daytime cumulus bringing few to sct CIGs to
most TAF sites this afternoon before clearing tonight. Winds
remain light, generally near to under 10 knots, out of the
north today but become light, under 5 knots, tonight, varying in
direction.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...KCM
AVIATION...KCM