Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 020435

Area Forecast Discussion
National Weather Service Des Moines IA
1135 PM CDT Thu Jun 1 2023

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

.DISCUSSION.../Tonight through Thursday/
Issued at 253 PM CDT Thu Jun 1 2023

Take Home Points:

*Rinse and repeat continues into weekend with scattered
*Drier air begins to filter in late weekend
*Reinforcing dry, and cooler, air slides in mid-week


Recent weather pattern will broadly continue to end the week and
start the weekend before transition will bring about drier, and
eventually a bit cooler, conditions. Effectively the lingering Rex
block will begin its transition towards an Omega block as the upper
level ridge/high retrogrades westward into the Northern Plains and
Canadian Plains by the weekend.

Hi-res/CAM guidance continues to, understandably, struggle with the
current weather pattern. With the absence of strong/notable features
driving PoP chances, instead being driven by weak forcing features
and air mass type convection, predictability remains on the low end
with regards to ultimate placement and to some degree coverage of
showers/storms. The result remains fairly widespread/blanketed low
to mid range PoPs to round out the week and start the weekend. As
has been mentioned previously, fortunately severe threats remain
minimal within this type of pattern (moist profiles, weak flow
through column, skinnier CAPE profiles), unfortunately the low
geographic predictability results in the broadbrushed PoPs more than
a few hours ahead of current. Some small hail, gusty winds will
be possible with strongest updrafts, but primary threat will
remain heavy rainfall due to slow motions and efficient rainfall
processes providing opportunities for 2 or more inches of rainfall
in relatively short periods of time. Scattered coverage will
limit issues overall, but urban areas will remain most
susceptible, as seen in previous days.

More specifically for the rest of today/tonight, morning HRRR runs
picked up shower/storm coverage depictions for the afternoon, which
have broadly come to fruition early this afternoon. Have adjusted
PoPs to account for this, otherwise previously mentioned
expectations/threats/concerns remain. Activity should ramp down
after 00z. LLJ activity is expected to primarily reside westward
into KS/NE, keeping much of the state quiet over night.

Into the weekend and next week, as the upper ridge/high slides
westward, a series of waves of drier air will begin to approach the
area from the E/NE. This will broadly result in a reduction in
shower/storm activity as it is shunted westward, though not
completely eliminate it with ribbons of moisture wrapping around the
central CONUS/Canadian ridge/high  and sandwiched in between pushes
of drier/cooler air. Result here being semi-uncertain precip chances
late weekend into early next week within guidance. The best chance
looks to be Monday/Monday night with a stronger push of drier/cooler
air as an area of high pressure slides southward behind eastern
Canadian/New England trough. While temperatures are expected to
remain seasonably warm, lower dew points will result in comfortable
conditions overall.


.AVIATION.../For the 06Z TAFS through 06Z Friday night/
Issued at 1135 PM CDT Thu Jun 1 2023

Thunderstorm activity has ended this evening, with just a few
lingering showers across far northern Iowa away from TAF sites.
Tomorrow will be another repeat of the trend this week,
thunderstorms will redevelop in the afternoon, lasting through
sunset, with impacts expected across all sites.




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