143
FXUS63 KDMX 300746
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
246 AM CDT Thu May 30 2024

.KEY MESSAGES...

- Showers and thunderstorms return this evening in western
  Iowa, expanding central and east on Friday. Severe threat
  remains quite low.

- Additional periodic showers and thunderstorms this weekend and
  into early next week

&&

.DISCUSSION...
Issued at 245 AM CDT Thu May 30 2024

The next wave on track for Iowa is making its way across the plains
early this morning. So far the only notable changes locally have
been increasing cloud cover across parts of western Iowa. As
the southern stream proceeds to produce an upper level cut-off
the low the entire pattern slows. This means that in Iowa
precipitation will be delayed, reaching parts of western Iowa
by this evening. SO while increasingly cloudy, today will be a
nice day in the upper 70s. Winds will become breezy with gusts
of 20-25+ mph by this afternoon as the pressure gradient
continues to tighten across the area.

Showers and thunderstorms finally enter the area this evening
and pass across the area through the overnight. CAMs have picked
up on a gradual fade out of the precipitation as it moves east
overnight as the southern stream cuts off forcing and better
moisture into the area. The extent is still very much up for
debate with the HRRR much more aggressive in diminishing
precipitation overnight with other CAMs hang onto spotty showers
through Friday morning. By Friday afternoon some redevelopment
of convection is expected along the boundary, though where
exactly that sets up will depend on how precipitation plays out
this evening. While the HRRR was most aggressive in fading
precipitation on Thursday night it is also most aggressive with
redevelopment on Friday afternoon. Given how the dominant
southern stream looks to prevent better moisture return, would
suspect that that solution is a bit overdone. In any case,
models show weak instability and little shear so any severe risk
with these showers and storms is quite low.

Models struggle to get this system out of the area with both the GFS
and Euro lingering a weak boundary across the area into Saturday
with the northern stream. This is followed up quickly with a
shortwave swinging across the northern plains and meeting Gulf
moisture into the area Sunday into Monday. And, as a more active
pattern sets up again, a more robust system looks to move
across the area Tuesday into Wednesday. While it is still
several days out and model inconsistencies exist, this system is
worth monitoring as better forcing looks to impact the area.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1124 PM CDT Wed May 29 2024

VFR conditions prevail through the current TAF period. Showers
and storms develop across western Iowa late Thursday afternoon
and evening, but latest model trends continue to suggest that
this activity will make very slow eastward progression and may
not reach any of the forecast terminal sites through 06z Friday.
Opted not to include any TS mention prior to 06z Friday for
now, but will need to be reassessed in future TAF updates.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Martin