233
FXUS63 KABR 070922
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
322 AM CST Thu Nov 7 2024

.KEY MESSAGES...

- Rather benign weather conditions are expected the next couple
  days as dry conditions prevail and temperatures remain near to
  slightly above normal.

- Temperatures will be above normal this weekend. There is a
  45-80% chance of rain Saturday into Sunday. Around one
  hundredth to one quarter inch of rain is expected, with an
  increased chance for precipitation over south central to
  northeastern SD.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 317 AM CST Thu Nov 7 2024

The main focus in this period will be on temperatures as our weather
pattern remains rather benign the next couple of days. Partly to
mostly cloudy skies cover a portion our eastern zones early this
morning while the rest of the forecast area is seeing clear skies.
Temperatures have been allowed to fall into the 20s in those clear
areas while low 30s have been hanging on in areas seeing the cloud
cover. That`s where we`ll begin the day as far as temperatures go.
An upper trough draped northeast to southwest from Ontario into the
Northern Plains will more or less wash out as it shifts eastward and
becomes detached from an upper low organizing across parts of the
southwest CONUS during the course of today into tonight. That upper
low is progged to shift out into the southern Plains on Friday with
the main branch of the northern jet traversing across southern
Canada through the end of the period.

Sfc high pressure will nudge eastward across Nebraska today lending
to broad west to southwesterly low level flow across the Dakotas.
After some morning low level cloudiness erodes across parts of
northeast SD and west central MN, the rest of the day will feature
mostly sunny skies across the entire forecast area. This should help
boost afternoon temperature readings a bit warmer than the previous
couple days with highs reaching the upper 40s to low 50s, which is
slightly above normal for this time of year. The only potential
drawback today will be an increasing southwesterly wind across our
north/northeast tier. Gusty conditions developing this afternoon,
especially over the Leola and Sisseton Hills, could see speeds
reach 30-35 mph. Skies remain clear tonight as temperatures fall
into the upper 20s to low 30s; still slightly above normal. Friday
should be another quiet day as sfc high pressure will maintains a
grip on the area. Other than some higher clouds drifting
overhead, winds will remain relatively in check. Above normal
temperatures will return with afternoon readings in the low to mid
50s.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 317 AM CST Thu Nov 7 2024

The deterministic models and clusters are consistent with an upper-
level low over CO working its way northeast through the evening and
overnight Friday. There is some variability with the location of the
low as it gets closer and over SD Saturday, with the ECMWF and NAM
having the upper-level low over central SD, the Canadian over
western SD, and the GFS, NBM and clusters over southeastern SD. The
location of the upper-level low affects the location of the surface
low and how much precipitation falls over SD. The NAM, ECMWF, and
Canadian have more widespread precipitation falling during Saturday
afternoon/evening. The GFS, NBM, and clusters however have the most
precipitation falling over south central and eastern SD through
Sunday morning. The NBM takes the precipitation further north than
the GFS or Clusters, as it has PoP values Saturday morning through
the evening ranging from 30-50% over north central SD, widespread 40-
60%, and 70-85% over south central to northeastern SD. NBM 24-hour
mean rainfall amounts have widespread accumulation of 0.1in-0.25in.
The clusters on the other hand have lower amounts as it has less
widespread precipitation, with the probability of receiving 0.01in
of precipitation 50% over north central SD and 100% over south
central and eastern SD, while the probability of receiving 0.1in of
precipitation drops dramatically to 20-60%, with south central and
eastern SD receiving the highest values.

Once the upper-level low moves out of SD Sunday, the flow becomes
more zonal with the models occasionally moving an upper-level
shortwave through SD (Canadian) or a small, weak upper-level ridge
over SD (GFS and ECMWF) on Monday and Tuesday. After Tuesday, the
models then move an upper-level trough over SD Wednesday, though the
timing, amplitude, and tilts of the troughs vary between the models
and clusters. The GFS and ECMWF develops some precipitation over
northern SD behind the upper-level ridge Tuesday evening through
Wednesday, as a surface low pressure moves through SD. The Canadian
however does not develop any precipitation as the mid-levels are dry
during that time and there is not a surface low pressure moving
through SD. The NBM and clusters follow the pattern in the GFS and
ECMWF by moving precipitation through northern SD. However, there
are scattered pockets of low PoP values in the NBM, at 15-25%, and
the clusters have 40-50% for 0.01in of precipitation to fall over
northern SD, which shows a spread in the likely hood for widespread
precipitation occurring. There are some hints in the clusters and
NBM for some of this precipitation to be snow or mixed precipitation
(a couple of members showing this), while the ECMWF p-type meteogram
shows a hint for rain mixed with sleet. This will need to be watched
in upcoming model runs to see if this trend for mixed precipitation
continues. One thing the models and NBM agree on is that there will
likely be stronger winds and gusts occurring as the low pressure
moves through SD Tuesday afternoon/evening into Wednesday evening.
The NBM shows winds picking up west of the Missouri River Tuesday
morning, with gusts getting above 30kts during the afternoon before
dying back around 20kts and spreading east.  Then winds speed back
up Wednesday with sustained winds over 20kts and gusts greater than
35kts over central and eastern SD.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1121 PM CST Wed Nov 6 2024

Terminals KABR,KATY,KPIR,KMBG

MVFR CIGs will have moved out of the KMBG area by the very
beginnings of the TAF period. Mostly VFR conditions are forecast
across the region through the nighttime hours, although models
suggest some patches of MVFR/IFR CIGs in the Glacial Lakes / KATY
region prior to sunrise, so have included a TEMPO group for this
possibility.

&&

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

$$

SHORT TERM...Vipond
LONG TERM...Vernon
AVIATION...TMT