232
FXUS63 KABR 270157 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
857 PM CDT Fri Jul 26 2024

.KEY MESSAGES...

- High heat and humidity will persist across the area
  through the next several days. On average, high temperatures will
  range about 5 to 10 degrees above normal.

- Elevated smoke from Canadian and western wildfires will continue
  to result in a milky sky with filtered sunshine. Some of this
  smoke may materialize near the surface, but widespread reductions
  to visibility are not forecast for the region at this time.

- There is a marginal risk (level 1 out of 5) for severe storms
  late this evening and overnight across mainly north central
  South Dakota. The chance for moisture is between 30 and 60
  percent. The main threat is gusty winds.

- There is a marginal risk (level 1 out of 5) for severe storms
  Saturday evening and overnight across the CWA. Chance for moisture
  ranges between 30 and 50 percent. Gusty winds and hail in excess
  of 1 inch are the primary concerns.

- There are additional chances for moisture Sunday and Sunday night
  (30 to 60 percent) and for Tuesday night and Wednesday (20 to
  30 percent).

&&

.UPDATE...
Issued at 849 PM CDT Fri Jul 26 2024

Expired the Heat Advisory on schedule back at the top of the hour.
Starting to get some post-frontal (mainly 700hpa fronto-forced)
showers and thunderstorms filling in and moving into north central
South Dakota, with the main push of mid-level shortwave lift
moving into swrn South Dakota. Inherited forecast grids have all
this well covered. No changes planned, at this time, to the
tonight period forecast.

UPDATE Issued at 622 PM CDT Fri Jul 26 2024

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.SHORT TERM /THIS EVENING THROUGH SATURDAY NIGHT/...
Issued at 335 PM CDT Fri Jul 26 2024

Much of the area east of the front is seeing ether heat index values
or temperatures at or in excess of 100 degrees. The front will make
a slow transition southeast, while storms out west river develop out
ahead of a subtle southwest flow shortwave. Those storms will move
towards the western CWA, but CAMS suggest really only north central
South Dakota could see anything migrate up across that area with a
very narrow ribbon of about 1500j/kg MUCAPE, with a decrease in
intensity/coverage during the late evening. A low level jet develops
(about 40kts) east of the front, so cant rule out anything
developing on the nose of the jet along the ND/SD state line, but
then moving away from the CWA early Saturday.

For Saturday, probabilities for exceeding 100 degree heat index
values is minimal.  Still looks plenty hot though, with the elevated
mixed layer (700mb temperatures +10 to +12C) hanging around.
Southwest flow aloft doesn`t show much of a shortwave until late,
that is when we also see a 40kt low level jet redevelop across the
east, with the nose again right up against North Dakota. CAMS are
pretty disorganized however, and NBM POPs are much higher than CAMS
would suggest. HREF MESH track are also pretty skimpy too...though
MUCAPE is quite a bit higher compared to tonight, on the order of
2500j/kg according to the NAM...so the risk any storms do present
will be higher in comparison to tonight.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 335 PM CDT Fri Jul 26 2024

An upper level shortwave trough and its associated shortwave energy
will track across the region Sunday through early Monday. The flow
will then become more zonal Monday afternoon and Monday night before
ridging develops on Tuesday. Another shortwave will slide across the
area on Wednesday, bringing some fairly strong energy with it.
Northwest flow then sets up Thursday and Friday as strong ridging
sets up over the western half of the country.

At the surface, showers and thunderstorms may be ongoing Sunday
morning ahead of an approaching trough, and in association with a 30
to 40 knot low level jet. By late afternoon, will see the trough and
an associated frontal boundary reach the western CWA, then track
eastward across the CWA during the evening hours. Some decent
instability will develop across the eastern part of the area, with
MUCAPE values of 1500-3000 J/kg. Shear will be a bit lacking,
generally around 25 to 30 knots, but the instability will likely be
enough to aid in some strong thunderstorm development Sunday
afternoon and Sunday night. High pressure will bring mainly dry
conditions to the region Monday into the day Tuesday. Will then see
another chance for showers and thunderstorms Tuesday night and
Wednesday as another low pressure system tracks across the area.
Will see some very strong instability across the eastern CWA during
this time (MUCAPE values of 3000-4500 J/kg). Shear will be in the 25
to 40 knot range Tuesday evening and Wednesday afternoon and
evening, possibly approaching 50 knots in some areas Wednesday
afternoon. Therefore, anticipate Wednesday could be another day with
strong, to possibly severe, thunderstorms. High pressure will move
back in and bring a return to dry conditions Thursday and Friday.

High temperatures will be in the mid 80s to lower 90s Sunday and
Monday, in the upper 80s to upper 90s Tuesday, and in the upper 80s
to lower 90s Wednesday, Thursday and Friday. Low temperatures will
be in the 60s through the extended period.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 622 PM CDT Fri Jul 26 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. Best chance for convection is at
KMBG but at this point the probability for seeing anything on
station is low, so at this point just carrying a "vicinity TS and
SH" for a few hours tonight during the window of greatest
probability for precipitation in the KMBG area.

&&

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

$$

UPDATE...Dorn
SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...Dorn