765
FXUS63 KABR 140933
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
433 AM CDT Sat Sep 14 2024

.KEY MESSAGES...
- Locally dense fog has developed in portions of central and north
central South Dakota this morning. Shouldn`t last too long into the
morning with ample sunshine.

- Chances for storms this afternoon/evening in central SD (20-30%
chance) with marginal (1 out of 5) risk for hail in excess of 1" and
damaging winds.

- Periodic and frequent chances for precipitation will be possible
next week. Greatest confidence in widespread rainfall will be late
Tuesday into Wednesday with a 50-80% chance for precipitation.

&&

.UPDATE...
Issued at 431 AM CDT Sat Sep 14 2024

Just a quick update to add a dense fog advisory in mainly north
central South Dakota.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 357 AM CDT Sat Sep 14 2024

Between the Missouri and James valley, fog is starting to
develop, albeit sporadically across the area. Anticipate this will
fill in under light winds and clear skies.

Winds though the day re-organize and become southeasterly again as
another southwest flow shortwave begins to lift into the region and
a surface low develops across western South Dakota this evening and
overnight. We end up with about a 10mb gradient across the state,
with pressure falls about 5mb through the afternoon...with 1/2km
winds increasing to about 25-35kts overnight. Winds should be a far
cry from those on Thursday, however.

The shortwave does provide the impetus for another round of
convection later today/tonight. We will have mid-level warm
advection and the NAM supports 2000j/kg MUCAPE today and about
1500j/kg overnight, though shear is only about 35kts at its peak.
HREF is a tick lower in comparison, but probably still good enough
for a localized SPC marginal risk as both HREF CIN and BUFKIT
profiles suggest convection could be surface based with hodographs
that show both, albeit weak, speed and directional shear.

850mb temperatures continue to increase into Sunday, at about a
standard deviation above climo.  Continued southeast low level flow
will also increase humidity, with the NBM probability of seeing a
dewpoint above 70 degrees at about 20-30 percent across northeast
SD/western MN.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 357 AM CDT Sat Sep 14 2024

The upper level flow across the CONUS will continue to exhibit a
negative PNA pattern through most of this period as a Rex Block
remains persistent across the eastern CONUS while upper troughing
will continue to reload through the period across the western CONUS.
The Rex Block in the east will lend to more uncertainty going
forward in time through this next week although there is general
agreement among deterministic/ensemble guidance as well as cluster
analysis showing the persistent upper low will just continue to
meander across the eastern U.S. through the end of the work week.
This will lead to the aforementioned upper low/troughing in the west
to continue to take up residence there leaving a quite active
southwesterly flow aloft pattern over our region through the end of
this period.

Beginning Sunday night through Monday, one of several upper waves is
progged by guidance to transit southwest to northeast across the
Dakotas. This will help aid in the development of 20-40% PoPs mainly
across the western half of the forecast area. Low confidence
continues in any widespread rainfall with this system. Ensemble
probs of seeing a 1/4 inch of rain remain 20% or less mainly across
central portions of SD. BUFKIT profiles also aren`t very favorable
looking with soundings taking on more inverted V patterns across
central SD. Not that there won`t be some showers, but probably more
scattered and lighter in nature is more the thought at this point in
time. This wave will exit the region sometime early Tuesday. We will
see a brief respite from the rainfall before next slug of moisture
arrives late Tuesday and persists through at least the first half of
Wednesday. Progs from guidance lends to more confidence in this
being a more significant wave and rainfall producer. NBM probs of
seeing a 1/4 inch in a 24-hr period ending at 7PM Wednesday
currently sit at roughly a 40-60% range. Probs for seeing a half
inch in the same time frame are 30-45% mainly south and east of a
line from Eagle Butte to Britton.

Windy conditions will return through the first part of the work
week, especially on Tuesday. Our region will be located in between
deepening low pressure across the Northern Rockies/Northern High
Plains and high pressure across the Great Lakes. Gusty south to
southeast winds look likely by Tuesday afternoon. NBM probabilities
of wind gusts reaching or exceeding 40 mph are highest between the
Missouri and James Valleys as well as across the Glacial Lakes area
ranging from 50-70%. With a persistent and active upper flow pattern
persisting, our forecast area will continue to see periodic chances
for additional precipitation through the end of the work week. Right
now, the window for drier conditions will be between late Wednesday
and Thursday afternoon. NBM ensemble data has gone with a blanket of
30-50% PoPs from Thursday night through Friday night across the
forecast area. As one might anticipate, this pattern will be
conducive to the continuation of above normal temperatures and
higher humidity values. We really don`t see much sign of any cool
downs until perhaps very late in the period into the following
weekend when readings could return closer to normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1225 AM CDT Sat Sep 14 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions, however there is the potential for fog at or near
the KABR/KMBG terminals later this morning. There is a low chance
for storms near the KMBG/KPIR terminals tonight as well, but too
low for inclusion in this TAF issuance. Winds will re-organize
and become primarily southeasterly today.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Dense Fog Advisory until 10 AM CDT /9 AM MDT/ this morning for
     SDZ003>005-009-010-015>017-034-035.

MN...None.
&&

$$

UPDATE...Connelly
SHORT TERM...Connelly
LONG TERM...Vipond
AVIATION...Connelly