865
FXUS63 KABR 161738 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1238 PM CDT Thu May 16 2024

.KEY MESSAGES...

- A weak disturbance will bring a 20 to 30 percent chance for
  showers and thunderstorms to areas along the North Dakota/South
  Dakota border this afternoon and evening.

- Above average temperatures can be expected on Friday with highs
  in the 80s. A few locations may exceed 90 degrees.

- A frontal boundary crossing the area late Friday afternoon and
  Friday night will be the focus for a 30 to 60 percent chance for
  thunderstorms. Some may be severe across parts of central South
  Dakota.

- Westerly winds with gusts of 35 to 45 mph will be possible
  Saturday afternoon. The highest wind gusts should occur over
  north central South Dakota.

&&

.UPDATE...
Issued at 1233 PM CDT Thu May 16 2024

Aviation discussion updated below for the 18Z TAFs.

UPDATE Issued at 946 AM CDT Thu May 16 2024

Made some minor adjustments to sky cover based on current
satellite trends. Otherwise, much of the forecast appears on track
for today. Still expect widely scattered showers and thunderstorms
across ND into parts of northern SD late this afternoon through
this evening and will maintain small chances (20-30%) PoPs for
this.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 318 AM CDT Thu May 16 2024

An upper level trough currently over the region will gradually track
off to the east today, with a more zonal flow setting up tonight.
Weak ridging then develops on Friday ahead of another approaching
shortwave trough.

At the surface, weak high pressure will remain over the area today,
with dry conditions expected most of the day. A warm front
associated with low pressure over Montana will set up along the
North Dakota/South Dakota border late this afternoon into the
evening, and may be the focus for some shower and thunderstorm
development. The better instability (MUCAPE of 1000-1500 J/kg) looks
to be a bit south of the boundary, so just looking at a small chance
(15 to 25 percent) for showers and non-severe thunderstorms across
the northern CWA. The overnight hours into the morning hours on
Friday will be dry, then the stronger cold front associated with the
low will approach, reaching the far western CWA by early Friday
evening. Very warm air will be ushered into the region ahead of the
front, which will result in some decent instability (MUCAPE of 1500-
2500 J/kg) developing over much of the CWA. Fairly strong shear
(bulk shear values of 40 to 60 knots) will occur along the front,
which looks to be the focus for thunderstorms (30 to 45 percent
chance) late Friday afternoon/early Friday evening across parts of
north central South Dakota. SPC has highlighted this area with a
Marginal Risk for severe weather, with strong winds gusts being the
main threat.

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

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 318 AM CDT Thu May 16 2024

The long term portion of the forecast begins on Friday night with a
frontal boundary pushing eastward across the region. Models have
trended drier across this CWA, with pcpn best along the frontal
boundary over North Dakota. Warm 700 mb temps (above the 90th
percentile) may cap convection over the southern, and perhaps the
eastern portion of the CWA. The convection should exit the CWA by
12Z Saturday with dry conditions and cooler temperatures moving into
the region. With the mid level trough near the CWA, along with a
tight pressure gradient, Saturday will feature westerly winds with
gusts exceeding 35 to 45 mph at times. ECMWF ensemble data suggests
there is a 60 percent chance wind gusts at KABR will be 35 mph or
stronger Saturday afternoon. The probability is higher further west,
especially over north central SD. If model trends continue, a wind
headline may be needed on Saturday.

Another low pressure system and upper level tough should cross the
region Sunday through Monday, bringing a round of showers and
thunderstorms. The pcpn potential is best, 30-50% Sunday night. Some
deterministic models are showing drier condition Monday into
Tuesday. However, with the region under the influence of an upper
level trough, isolated to scattered showers and thunderstorms may be
possible at times.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1233 PM CDT Thu May 16 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast to prevail through the TAF period.
Late this afternoon and through the evening, a few widely
scattered -SHRA/-TSRA are possible along the ND/SD border.
Confidence is very low as to whether or not any of this activity
makes it as far south as KMBG/KABR, so won`t even include a
vicinity (VC) mention at this time, but may consider for the 00Z
TAFs once activity becomes more apparent. Any storms that develop
would likely remain VFR CIGs, but could contain MVFR VSBY and
brief gusty surface winds over 35 knots.

&&

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

$$

UPDATE...TMT
SHORT TERM...Parkin
LONG TERM...SD
AVIATION...TMT