058
FXUS63 KABR 061732 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1232 PM CDT Mon May 6 2024

.KEY MESSAGES...

- Strong winds will translate eastward this morning with gusts to
  around 50 mph across the entire area through Monday evening.

- Strong low pressure will bring showers and thunderstorms to the area.
  Strong to severe storms are possible this afternoon through mid
  evening. A marginal risk (1 out of 5) for severe storms extends
  southwest of a line from Miller to Mobridge.

- The weather pattern will remain unsettled through Thursday with
  periods of showers and thunderstorms. Below average temperatures can
  be expected through at least Friday, with perhaps a warming trend
  next weekend.

&&

.UPDATE...
Issued at 1223 PM CDT Mon May 6 2024

See updated aviation discussion below.

UPDATE Issued at 1010 AM CDT Mon May 6 2024

A line of showers and thunderstorms currently extends from just
north of Mobridge to southeastern South Dakota. This area will
continue to track northward this morning, then looks to exit the
area by early afternoon. Still expecting additional shower and
thunderstorm development later this afternoon and evening. SPC has
increased the risk to a sight risk across the western part of the
CWA, mainly west of the Missouri River, with it looking like there
will be a short window (21Z to 00Z) for storms strong enough to
produce gusty winds, hail, and possibly a tornado. No other
changes made to the forecast at this time.

&&

.SHORT TERM /TODAY THROUGH TUESDAY AFTERNOON/...
Issued at 450 AM CDT Mon May 6 2024

Showers and thunderstorms have begun in central SD this morning
ahead of a Rocky Mountains low that will move into western SD this
afternoon. The track of the low has shifted over the last 24 hours,
staying farther west than in previous runs which had it move over
central SD. This has altered the atmospheric profile a bit regarding
placement of strongest winds and areas with best potential for
strong to severe storms this afternoon/evening. There looks to be a
narrow band of clearing that could provide additional heating and
instability, but not sure if that will make it into this cwa by 21z
or if it will now stay just off to the west. The 0z NAM and some NAM
derivatives left it over UNR`s cwa, also shifting some better
helicity farther west, as well, but the 6z NAM12 returned a tornado
parameter of 1 to Stanley county by 21z. Still, the potential for
low-topped supercells in 800 to 2500 J/kg of CAPE that pivots from
Stanley county north and east of the James valley through the
afternoon and evening remains a concern. Bulk shear is high at 45 to
60 kts, and with 55 kt winds just off the sfc in a llj at 850mb, it
won`t take much to enhance winds to 60 to 70 mph in a thunderstorm.
SPC did expand the marginal risk (1 out of 5) to include most of
central SD into Hand County this afternoon.

Expect a period of drying overnight into Tuesday as the low moves
into southwest ND. NBM still plasters some hefty pops over the
region through Tuesday, but the uncertainty is high regarding the
potential for some showers to wrap back in. Blended in ConsSHORT and
then blended to neighbors for some continuity for pops from 6z
tonight through 0z Wednesday.

&&

.LONG TERM /TUESDAY EVENING THROUGH SUNDAY/...
Issued at 450 AM CDT Mon May 6 2024

Tuesday night continues the saga of a long lasting low over the
area. This low circulates over the region through Wednesday and then
starts to move southeast over SD on Thursday before finally exiting
the area Thursday night. Friday, the upper level pattern consists
mainly of northerly flow. After this, things get a little messy.
Clusters show the area on the upwind side of a trough with a ridge
moving in from the west. Deterministic models are showing a trough
dropping in from the south. The Canadian and EC show this trough
attached to a low in northern Canada. This trough moves across the
area fairly quickly and a northwestern flow takes over Saturday
evening, remaining in place through the end of the period. The GFS
has a low in southern Canada causing the trough, and moves things
quite a bit slower with the trough remaining dominant through the
end of the period.

Rain chances have decreased somewhat Tuesday night through Wednesday
morning compared to previous model runs. However, they remain
similar for Wednesday afternoon and evening at around 40 to 60%.
Slight (20 to 30%) chances remain through the day Thursday as the
low makes its way across SD. The chance of more than 0.25 inches of
rain stays below 20% for the entire period. NBM is keeping precip
chances to a minimum Friday through the end of the period as drier
air moves into the region.

Temperatures remain at or below average through Saturday. Sunday and
Monday are expected to be slightly above average. Winds could still
be strong Tuesday evening west river, but for the rest of the period
stay around normal.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1223 PM CDT Mon May 6 2024

Terminals KABR,KATY,KPIR,KMBG

Southeasterly winds of 20 to 35 knots, with some gusts up to 45
knots, will occur across the area this afternoon and this evening.
IFR/MVFR cigs over central South Dakota will spread eastward late
this afternoon and this evening. The low cigs will then remain
over the east through the end of the TAF period, but should see
cigs lift to VFR levels across the west overnight into Tuesday
morning. Scattered showers will affect eastern parts of the area
early this afternoon. Will see additional shower and thunderstorm
development over parts of central South Dakota this afternoon and
this evening. There may be a few strong to severe storms that may
produce strong winds and large hail. Another area of showers and
thunderstorms will develop along and east of the James River
Valley this evening into the early overnight hours. No severe
weather is expected.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until midnight CDT /11 PM MDT/ tonight for
     SDZ003>011-015>023-033>037-045-048-051.

MN...Wind Advisory until midnight CDT tonight for MNZ039-046.

&&

$$

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