198
FXUS63 KABR 281721 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1221 PM CDT Fri Jun 28 2024

.KEY MESSAGES...

- There is a Marginal Risk (1 out of 5) for severe weather for
  much of the area later today. A few strong to severe
  thunderstorms are possible late this afternoon and this
  evening, but widespread thunderstorm activity is not expected.

- Another opportunity for showers and thunderstorms will arrive
  later Sunday into Monday (30-70% chance of measurable rain).

&&

.UPDATE...
Issued at 1220 PM CDT Fri Jun 28 2024

See below for an aviation forecast discussion for the 18Z TAFs.

UPDATE Issued at 952 AM CDT Fri Jun 28 2024

No changes planned to the today period forecast. Later this
afternoon/evening, there will be a wind-shift/frontal boundary
sweeping through central/north central South Dakota. Not much
instability (mlCAPE ~250-500J/kg), but the deep layer shear is on
the order of 45 to 55 linear hodograph knots (high shear/low CAPE
environment). Not suggesting there will be copious amounts of
severe thunderstorm activity later, but if a couple of
thunderstorms were to develop, they would likely be supercellular
and not very tall and probably not look like all that much on
radar. Will have to see what type of wind/hail threat there could
be.

UPDATE Issued at 623 AM CDT Fri Jun 28 2024

See updated aviation discussion below.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 312 AM CDT Fri Jun 28 2024

The region will be under upper level southwest flow today ahead of
an approaching shortwave trough. This trough will track across the
CWA tonight, leaving northwest flow it its wake on Saturday.

At the surface, an area of rain and thunderstorms is currently
tracking across the eastern part of the CWA, and expect this
activity to exit to the east by early this morning. Conditions will
be fairly quiet during the day, then the region will become situated
between low pressure to the east and high pressure to the west
tonight. Not much in the way of instability expected later this
afternoon and evening, but will see some areas of shear in excess of
60 knots. CAMs are indicating the potential for a few thunderstorms,
but do not expect widespread activity. The high to the west will
track eastward and settle in over the Northern Plains on Saturday,
keeping conditons dry and a bit cooler.

High temperatures today will be in the upper 70s to lower 80s. Low
temperatures tonight will be in the 50s. Highs on Saturday will be
in the mid 60s to lower 70s.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 312 AM CDT Fri Jun 28 2024

Saturday night, we start the long term on the downwind side of an
approaching ridge. This will remain in place through the day Monday.
Monday evening, an upper level trough will make its way across the
region bringing a chance for rain and possibly some severe storms.
After that, we pretty much stay in a trough pattern aloft. A couple
shortwaves move through and Thursday night an upper level low starts
to move down out of Canada. This is still 6 days out so there is a
lot of variation in tracks. The GFS has the strongest low at the
moment but generally keeps it in northern ND and MN. The EC has the
weakest low and brings it into northeastern SD. The Canadian is in
the middle and brings the low right across SD into northwestern IA.

Our first chance for some precipitation will be Monday as that upper
level trough moves through the region. This is expected to move
northeast through the day bringing the warm front up from the south.
Some severe storms could form along this boundary or along the cold
front behind it. SPC has already highlighted most of eastern SD in a
15% risk for severe storms. Tuesday and Wednesday will feature
slight to chance pops (15 to 25%) as we continue in a trough pattern
with some energy moving across. Thursday, ahead of the low, chances
increase to 35 to 50% through the day. Storms are possible, however,
severe potential is uncertain.

Temperatures throughout the period will be in the mid 70s to mid
80s, between 10 degrees below average and right around average.
Sunday afternoon could have some gusts of 30+ mph around and west of
the Missouri River as a result of a stronger pressure gradient ahead
of the incoming low. Gusts around 30 mph are expected to continue
through the overnight hours and into Monday moving west to east and
diminishing Monday evening. For now, winds look to remain around
normal for the rest of the period.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1220 PM CDT Fri Jun 28 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are occurring and are forecast to persist late into
tonight. At that point, short term guidance has a back door cold
front sweeping south through the CWA, dragging some sub-VFR
stratus clouds down into the region. Generally, at some point
between 09Z and (at least) 15Z Saturday, expect most terminals in
the region to be experiencing an MVFR ceiling.

&&

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

$$

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