108
FXUS63 KABR 201510 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1010 AM CDT Sat Jul 20 2024

.KEY MESSAGES...

- A plume of Canadian wildfire smoke at high altitudes will
  filter out the sunshine today.

- There are daily precipitation chances (20 to 40 percent) today
  through Tuesday (mainly afternoon and evening activity).

- Confidence is increasing for hot temperatures returning by the end
  of the week and next weekend.

&&

.UPDATE...
Issued at 1008 AM CDT Sat Jul 20 2024

The forecast remains on track this morning. No major changes are
planned.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 351 AM CDT Sat Jul 20 2024

The main issues in this period will revolve around fog and precip
chances during the course of the next couple of days. Temperatures
early this morning remain in the 60s with light and variable winds
couple things notable on satl early this morning. First, low clouds
and fog continues to develop across southeast SD and creeping
gradually creeping northward. Second, a mid level trough axis
located over the SD/MN border is pinwheeling southward. Tackling the
fog prospects first as we go through the pre-dawn hours. Short-range
hi-res guidance points to the low clouds/fog in southeast SD will
continue moving northward and envelop our southern/southeastern
zones. Additional new development is also certainly possible up/down
the James Valley and other zones between the Jim and Mo Valleys. Its
anticipated to persist for a while after sunrise, but should burn
off by mid morning. Hi-res model guidance indicates a wide swath of
Canadian wildfire smoke will drift southward across the Dakotas and
MN today. It is expected to remain in the upper levels of the
atmosphere so there is no air quality concerns, but it will act as a
bit of a filter to the anticipated sunshine today.

The aforementioned mid level trough will continue to move south and
away from our forecast area today. The sfc tough associated with
this feature will also continue to drift away from us into southeast
SD/northwest IA today. Our region will remain in northerly flow
aloft...between an upper ridge across the Great Basin into the
Northern Rockies while a upper trough remains present across the
Great Lakes into the New England. Our area will be closer to and the
vicinity of the upper trough and we will continue to see weak mid
level impulses flow through the region. Daytime heating with a humid
air mass in place will lead to increasing instability this afternoon.
Deep layer shear remains weak, so we expect afternoon convection to
develop and remain widely scattered and mostly sub-severe. Some of
the CAM solutions show very little in the way of any convection this
afternoon and/or at best very isolated in coverage. So, confidence
seems to be leaning toward more locales could remain dry. We`ll go
ahead and repeat this same scenario during the daytime on Sunday.
Although, some early morning convection could be possible as it
drifts southward into our forecast area from a back door frontal
boundary across northern MN/eastern ND. A sfc trough located across
western SD during the day and again a repeat of atmospheric
conditions by Sunday afternoon will lead to more scattered
convection that should for the most part remain sub-severe.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 351 AM CDT Sat Jul 20 2024

The region remains in northerly flow aloft with weak high pressure
at the surface through the first half of the extended period. Pretty
good model agreement in this scenario, which will also lead to a
prolonged period of generally light winds with the broad surface
high in place. That said, we keep a fairly moist air mass in place,
with NBM dewpoints in the low to mid 60s through mid-week. With the
coolish temps aloft, there`s still a signal showing up for daytime
heating showers and thunderstorms Monday and Tuesday (eastern CWA)
afternoons. Models continue to show upper level ridging building in
by the end of the week, with high confidence supported by clustering
analysis. Grand Ensemble continues to show 850mb temps reaching +20C
or higher for areas along and west of the James River. Will continue
to advertise high temps reaching the 90s by the end of the upcoming
week as GEFS/ENS/GEPS all showing high probabilities (>60%) of
reaching 90 degrees or higher across central SD and even into the
James River valley. It would appear precipitation chances really
start to wane as well.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 631 AM CDT Sat Jul 20 2024

Terminals KABR,KATY,KPIR,KMBG

FG/BR is affecting the region this morning, especially at
KATY/KPIR where VSBY has been down to 1/4 SM. Expect areas of
MVFR/IFR VSBY across the region to burn off by around 14Z, making
way for VFR conditions for the rest of the day. There is some
potential for FG/BR tonight as well, mainly in the KATY region and
will examine this in further TAF issuances. Smoke aloft is also
blanketing the region and have inserted SCT250 in the TAF sites to
account for this layer of smoke aloft. Also cannot rule out a
stray thundershower or two across the area today, but with chances
and areal coverage so small, will leave mention out of TAFs at
this time unless something approaches on radar.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...Wise
SHORT TERM...Vipond
LONG TERM...TMT
AVIATION...TMT