000
FXUS63 KDMX 200452
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1152 PM CDT Fri Apr 19 2024

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Cool temperatures persist with widespread freeze conditions
  anticipated tonight and especially Sat night. Area wide Freeze
  Warning tonight.

- Two systems with showers and storms likely next week, around
  Monday and then again late Thu into Fri

&&

.DISCUSSION...
Issued at 346 PM CDT Fri Apr 19 2024

Our pattern will continue to be driven by northern stream
influences through the middle of next week, before western CONUS
troughing and Plains southwest flow returns toward the end of
the forecast period late next week. In the mean time, the main
weather theme for the next few days will remain cool
temperatures with two more nights of frost and/or freeze
concerns. Some weak mid level forcing will keep some mid level
cloudiness to our south, but mostly clear skies over much of the
area after the northern diurnal cumulus dissipates. Winds will
stay up sufficiently to preclude much frost development
overnight however, but with lows still at or several degrees
below freezing another round of headlines are required in the
form of a widespread Freeze Warning overnight. The pattern won`t
change too much into tomorrow either with the Great Lakes mean
trough still in place with persistent MO Valley surface high
pressure. Some frost will be possible tomorrow night, but
considering low temp expectations toward the very low end of the
guidance suite with better radiational cooling potential than
tonight another Freeze Warning is more likely.

The next system of concern is still a long way off, not even
really approaching the Pacific NW yet, but its eventual track
should reach BC/WA late Saturday and then the northern Plains
late Monday. Weak mid level forcing, and especially lower based
warm advection will set the stage for warmer temps and some low
end precip chances by afternoon, but additional convection may
develop with the maturing low level jet interacting with the
frontal boundary, especially if the slower ECMWF solution
verifies. While the deep shear will be strong, the lack of
instability will preclude any strong-severe potential.

Plains upper ridging will then return by midweek starting our
transition to a slowing approaching western CONUS trough and
persistent southwest flow influences for the end of the period
and beyond. Deterministic solutions have shown little agreement
on the ejection of the initial appreciable short wave, but even
overlooking the smaller scale details the EPS and GEFS solutions
suggest a prolonged broader warm/theta-e advection pattern that
may start Thursday and persist through and beyond the valid
period with the surface features not arriving until the weekend.
This could result in appreciable precipitation accumulations
over a several day period, mainly due to duration versus
magnitude. SLU/CIPS analogs and CSU AI/ML solutions also suggest at
least some severe potential as well, especially south.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1149 PM CDT Fri Apr 19 2024

VFR conditions will prevail through the period. Sporadic wind
gusts held on longer than anticipated this evening, especially
at KDSM where gusts are still being reported. Therefore, have
kept gusts going for a few more hours at KDSM to account for
this, but these likely won`t be overly persistent. Otherwise,
light NW winds this morning pick up again after sunrise with
gusts of 20 to 25 kts likely at all sites.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 8 AM CDT Saturday for IAZ004>007-015>017-
023>028-033>039-044>050-057>062-070>075-081>086-092>097.

&&

$$

DISCUSSION...Small
AVIATION...Dodson

NWS DMX Office Area Forecast Discussion