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000
FXUS63 KDMX 101733
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1233 PM CDT Wed Apr 10 2024

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Warmer and dry Wednesday.

- Gusty winds and dry conditions creating increased fire weather
  concerns on Thursday and potentially Friday. Chance of showers
  East and North Thursday (30-40%) but will amount to under
  0.1".

- Unseasonably warm through the weekend with highs nearing 80
  degrees.

-Next chance of rain and storms arrives late Monday. Confidence
 is high (>65%).

&&

.DISCUSSION...
Issued at 403 AM CDT Wed Apr 10 2024

High level clouds associated with the ongoing storm system in Dixie
Alley began to approach the state overnight. High pressure will move
to the east today, but fair weather will remain with highs near 70.
Clouds from the south will continue to build in as the upper level
low negatively tilts and ejects into the Midwest Thursday. Moisture
associated with this system looks to mostly miss the area. The main
source of moisture will be accompanied with a descending shortwave
from the north, but the moisture content will still be minuscule.
Only 20 percent of ensemble members give central Iowa over 0.01" of
rain. HREF members focus this precipitation in the north where the
shortwave will begin to phase with the trough to the east. Expect
coverage to be in the form of sporadic showers.

The pressure gradient will tighten as the upper level feature
deepens and will be assisted by a series of PV anomalies arriving
from the Dakotas. The outcome of this will be gusty winds Thursday
afternoon. Cold air advection in the evening will preserve the
mixed layer past sunset and lead to some gusty winds early in
the overnight hours. Paired with the winds are fire weather
concerns as mentioned in previous discussions due to the
decrease in RH values. The coverage of rain and clouds makes
this a questionable factor, however, as mixing and dryness could
both me mitigated. The focus for fire weather will be in the
southwest where clearing is anticipated in the afternoon hours
and RHs could drop into the 20s. Trends will continue to be
monitored.

Friday is another day with fire weather concerns. Gradient winds
will focus in the east through the morning before departing through
the late afternoon. RH values will drop into the low to mid 20s for
much of the area, but look to be spatially displaced from higher
winds. Still, dry and windy conditions are in place for parts of the
day and will warrant monitoring.

A thermal ridge will build into the Plains states over the weekend
with H850 temps approaching 16C overhead for the western half of the
state which will make for highs near 80. Lee cyclogenesis and
subsequent convection over the Plains will break down the extent of
the thermal ridge, but will keep Iowa in the warm sector as the
system advances early next week, bringing a chance for thunderstorms
Monday evening and overnight. Timing and placement of the system
will be better agreed upon with time so will postpone further
evaluation of severe weather potential for later forecast
issuances.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1231 PM CDT Wed Apr 10 2024

VFR cumulus has developed over northern Iowa, while high clouds
continue to stream into southern Iowa early this afternoon.
Ceilings are expected to remain VFR through the rest of the day
and into the overnight, although some MVFR conditions may
develop for a few hours tomorrow morning. Otherwise, main
impacts to aviation will be light winds with variable directions
over southern Iowa near KOTM and KDSM, then gusty winds
developing area wide early tomorrow morning.

&&

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

&&

$$

DISCUSSION...Jimenez
AVIATION...Dodson