713
FXUS63 KDMX 090422
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1122 PM CDT Tue Oct 8 2024

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

.KEY MESSAGES...

- Mild and quiet weather continues for several more days, with
  near record highs possible Thursday and Friday.

- A series of cold fronts will bring successively cooler
  temperatures from late Friday into early next week. By Monday
  highs will only be in the 50s, and on Tuesday morning much of
  Iowa will fall near or below freezing.

- No rain is foreseen in the next seven days and even beyond.

&&

.DISCUSSION...
Issued at 202 PM CDT Tue Oct 8 2024

The weather remains exceptionally quiet across the region with
clear skies, light southwest breezes, and above normal
temperatures reigning this week. Over the next few days the only
wrinkles in the forecast are smoke potential and temperatures.
On the latter point, some satellite channels do show smoke
streaming over the High Plains and the HRRR is picking up well
on this, however, the smoke is high-level and very thin and
appears barely detectable visually. Have thus introduced some
low Sky cover values during the day Wednesday when the smoke is
progged to be more across the southwest half or so of Iowa, but
even then only 20-40 percent Sky grids have been included and
there should be no sensible impacts.

As far as temperatures are concerned, the big weather story of
the next few days will be increasing warmth with highs
approaching record levels both Thursday and Friday as detailed
in the Climate section below. While ridging and warm air aloft
certainly support this warming trend, there is a relative lack
of low level winds/mixing depicted in forecast soundings, so
have not gone much above guidance envelope. Even so, highs are
forecast in the low to mid 80s Wednesday, then around the mid
80s Thursday and Friday. The warmth will be brought to an end by
a cool front dropping across Iowa Friday afternoon and evening,
tempering highs a bit in the north on Friday and bringing
notably cooler weather later in the weekend. With the frontal
passage on Friday the parent mid-level trough will be passing
far to our northeast and the boundary fading somewhat as it
comes through, so while there will be a wind shift and
temperature drop it does not appear to have a strong push behind
it and even on Saturday highs will still be in the mid 70s to
lower 80s across the forecast area.

By Saturday a more energetic 500 mb shortwave trough will be
diving from south central Canada down toward North Dakota,
subsequently digging into southern Minnesota and carving out a
large cyclonic trough over the Great Lakes and Quebec by early
Sunday and persisting into the first half of next week. Within
this scenario a much stronger cold front will surge across Iowa
late Saturday into Saturday night, followed by reinforcing shots
early next week bringing the coldest weather of the season so
far around Monday. NBM guidance is rapidly catching up to the
expected magnitude of cold, with Monday highs now only in the
mid to upper 50s and Tuesday morning lows near or below freezing
across much of Iowa. This will be a shock to the system for many
of us given our recent and preceding persistently warm weather.
Enjoy the mildness while it lasts this week!

Finally, in other news, no rain is forecast in the next seven
days. Even in the middle to later part of next week long range
models indicate a return of mid/upper level ridging which would
not support rain chances then either. Drought conditions are
beginning to slowly worsen across much of the region, however
this is tempered by the lack of vegetative impacts and
relatively low climatological precipitation normals at this time
of year.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1116 PM CDT Tue Oct 8 2024

VFR conditions continue. Late in the TAF period, a weak
boundary will cross the region, causing surface winds to become
more easterly.

&&

.CLIMATE...
Issued at 202 PM CDT Tue Oct 8 2024

Unseasonably warm temperatures on Thursday and Friday will
approach daily record values for sites across the area. Records
are included below for climatological reference.

Thursday, October 10th Daily High Records:

Des Moines:  88F (1962*)   Current Forecast: 85F
Waterloo:    89F (1928)    Current Forecast: 85F
Mason City:  87F (1928)    Current Forecast: 84F
Ottumwa:     89F (1930)    Current Forecast: 83F
Lamoni:      92F (1931)    Current Forecast: 82F

Friday, October 11th Daily High Records:

Des Moines:  86F (1962*)   Current Forecast: 86F
Waterloo:    90F (1920)    Current Forecast: 86F
Mason City:  85F (1928*)   Current Forecast: 80F
Ottumwa:     86F (1962)    Current Forecast: 86F
Lamoni:      84F (1962*)   Current Forecast: 83F

*Record occurred in multiple years

&&

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

&&

$$

DISCUSSION...Lee
AVIATION...Jimenez/DMD
CLIMATE...Lee