984 
FXUS63 KDMX 170452
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1052 PM CST Sun Nov 16 2025

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

.KEY MESSAGES...

- Cool and dry with increasing clouds tonight into Monday

- Breezy on Monday. Rain chances increasing through the
  afternoon, with a few rumbles of thunder possible south. Snow
  may mix in with rain in the north. 

- Slight warming through mid-week

&&

.DISCUSSION...
Issued at 243 PM CST Sun Nov 16 2025

<< DRY AND MILD TODAY, PRECIPITATION RETURNING THIS WEEK >>

Quiet and mild conditions are in place over the state today, as 
surface high pressure dominates the pattern. Cloud cover has slowly 
increased from the west, but is struggling as it moves into the very 
dry airmass over Iowa. These clouds will eventually span much of the 
area, which combined with increasing winds, should help keep 
temperatures from plummeting tonight. The increasing winds tonight 
and breezy conditions on Monday will be indicative of the tightening 
pressure gradient in response to lee-side cyclogenesis in the 
plains. This cyclogenesis is coincident with the PV anomaly that is 
now making it's way through the Rockies, which will eventually track 
through Iowa and bring our next chances for precipitation late 
Monday into early Tuesday.


<< MONDAY/TUESDAY SYSTEM: MOSTLY RAIN, BUT SOME THUNDER AND SNOW? >>

As the wave passes across the plains tomorrow, a strong push of 
theta-e advection will lift into the area. The associated plume of 
low and mid-level moisture will work to saturate through the dry 
antecedent air mass, eventually saturating down to the surface 
through late Monday afternoon and evening. Precipitation will 
increase in likelihood farther north and east in Iowa, although 
occasional rain/showers are possible throughout the area Monday 
afternoon and evening. A stout warm nose in the mid-levels will keep 
precipitation as mostly rain over central and southern Iowa. With 
this warm nose in place, lapse rates even steepen enough to 
produce some instability aloft, introducing the potential for a 
few rumbles of thunder as rain moves through. This will be most 
likely in the southern half of the forecast area where 
instability values could approach 200 to 300 J/kg, depending on
the model you pick. Any convectively driven parcels would be 
rooted quite a ways aloft, but with the cold profiles, can't 
rule out some small hail, which this time of year may perceived 
as sleet, although the processes for creating the two types of 
ice pellets does differ.

The precipitation forecast becomes a bit trickier over northern Iowa 
where colder air and stronger forcing will bring potential for 
wintry precipitation Monday night into Tuesday. Along and just north 
of the Iowa/Minnesota border, a band of stronger frontogenetical 
forcing will set up in the 800 mb to 700 mb layer generating strong 
lift up into the dendritic growth zone. The warm nose aloft is 
coming in a bit weaker with today's guidance as well, resulting in a 
temperature profile nearly isothermal along the 0 C isotherm 
once saturation occurs. Surface temperatures and wet bulbs are 
still forecast to be above freezing, but if that stronger 
forcing leaks into far northern Iowa, it's possible the shallow 
surface warm layer won't be able to melt the volume of snow 
falling into it. If these heavier rates come to fruition, areas
in northern Iowa could pick up a quick inch or two of snow 
Monday night/Tuesday morning. Of course, if this better forcing 
sets up north of the area, or the warm nose is a few degrees too
warm, precipitation would fall as a cold rain instead. Right 
now, the expectation is still that the bulk of the snow is going
to stay to our north. Mostly rain will fall in our forecast 
area, with occasional snowflakes mixed in along the northern 
border. If a change over to snow does occur and we see 
accumulations south of the Iowa/Minnesota border, deterministic
and ensemble guidance both suggest it would be most likely in 
areas north of highway 18. Even then, recent warm conditions 
should have ground temperatures warm enough to melt the snow as 
it falls, further reducing any accumulations. 

Through early Tuesday morning, deeper saturation will fade in and 
out as drier air works into the mid and upper levels, reducing ice 
introduction. Low level saturation will stick around through the 
morning hours, keeping low clouds. Brief drizzle may still be 
possible through the morning on Tuesday, but a relative lack of lift 
in the low levels is going to be working these chances. Likewise, 
the saturated layer isn't looking nearly as deep as it did in 
soundings yesterday, further diminishing the potential. Like with 
the snow, if drizzle does occur, surface and ground temperatures 
should be warm enough to negate significant freezing in northern 
Iowa.


<< REST OF WEEK, THURSDAY/FRIDAY SYSTEMS >> 

Although they may not be as supportive for drizzle, saturation in 
the low levels will keep low cloud cover overhead through much of 
Tuesday, keeping temperatures cool through the day. For this reason, 
have knocked high temperatures down a few degrees on Tuesday as 
guidance is likely too aggressive with mixing out the boundary layer 
given the cloud cover and CAA. By Wednesday, return flow develops on 
the back side of the Great Lakes high, bringing warmer temperatures 
through the middle of the week. By Thursday, two 500 mb waves will 
pass through the central US and Canada, influencing the weather 
through the second half of the week. How these two waves interact 
will be worth watching, as the GFS brings the northern wave far 
enough south to keep the southern wave suppressed and the 
precipitation south of Iowa, while the ECMWF shows the southern wave 
lifting up into southern Iowa, bringing widespread rain chances to 
Iowa on Friday. More on these systems in the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1051 PM CST Sun Nov 16 2025

High clouds are expected, with limited mid-level cloud cover
moving east out of the state this morning, followed by more
widespread mid-level to even low VFR ceilings by the afternoon 
and especially the evening. This is due to a system moving into
the region, which will bring rain chances into the state after 
20z, spreading eastward with higher probabilities into the 
evening, where some periods of MVFR conditions may occur. There
remains a low chance for thunder at KDSM and KOTM but specific 
mention remains out of the terminals at this time and will 
continue to be monitored. Winds out of the southeast will 
increase through the morning and into the afternoon, with gusts 
up to 20 knots to isolated 25 knot values at times.

&&

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

&&

$$

DISCUSSION...Dodson
AVIATION...Bury