Expires:No;;019662
FXUS63 KDMX 111120
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
620 AM CDT Sat May 11 2024

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

* Pleasant day today - mid-upper 70s highs with NW winds and 
  low humidity. 

* Showers/storms return Sunday PM through at least Monday night - 
  severe chances very low.

* Additional shower/storm chances mid-late week - details hard
  to come by as guidance diverges

&&

.DISCUSSION...
Issued at 312 AM CDT Sat May 11 2024

After an ideal evening and overnight for aurora viewing across most 
of Iowa, today too will be ideal from a Spring weather perspective. 
Northern stream shortwave trough will continue to glide through the 
Great Lakes and Ohio Valley regions, leaving in its wake general NW 
flow and broad subsidence to weak lift. With a substantially dry 
airmass in place, only a few higher based clouds may be seen as the 
boundary layer attempts to mix to near 700mb. Aside from some weaker 
gusts to around 20mph, it will be incredibly difficult to complain 
about a day filled with sunshine, highs in the 70s, and low 
humidity. Enjoy it if you can!

Sunday will start out quiet enough, but winds will have switched 
southerly as the western trough begins to slide off the Rockies and 
exert its influence. Deterministic and ensemble guidance remain in 
broad agreement on increasing moisture return and chances for 
precipitation returning by Sunday evening. The GFS/GEFS members have 
slid towards the Euro suite, meaning the primary change/consequence 
being lesser opportunity for accumulating precipitation over 
northern/northwest areas of Iowa. Potential for stronger/severe 
storms remains low with woeful wind fields expected. There could be 
a low-end heavy rainfall risk over southern areas with a combination 
of initial evening MUCAPE values in excess of 1000 J/kg, mean flow 
under 20kts, and overnight Corfidi vectors suggesting extremely slow 
to nil propagation. Working against though will be a weak LLJ and by 
virtue moisture transport. Overall precipitation activity will 
linger over central to southern areas much of Monday, and possibly 
into Tuesday over SE areas, before the parent upper low slides 
eastward across Missouri and into Illinois and the lower Ohio 
Valley. 

Guidance continues to consistently signal additional activity by 
Wednesday into Thursday as shortwave energy slides southeastward out 
of British Columbia, but this is also where deterministic guidance 
begins to diverge more substantially in their handling of this 
energy and beyond. Extremely hard to hang your hat on any details, 
aside from shower/storm chances in general Wednesday into Thursday, 
let alone to end the week into next weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 617 AM CDT Sat May 11 2024

VFR is the name of the game today. Winds will predominantly be
out of the NW around 10kts with G20kts possible at times. Winds
then quickly turn southerly after 00z, but under 10kts. Little
cloud cover today, deep mixing may yield FEW090 in addition to
eroding FEW250.


&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...Curtis