Worthing, South Dakota Weather Forecast Discussion

677
FXUS63 KFSD 190718
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
218 AM CDT Fri Sep 19 2025
.KEY MESSAGES...
- Scattered showers and very isolated thunderstorms will
  continue into Saturday, with the greatest coverage on Friday.
  A very low chance of a weak funnel is possible Friday
  afternoon.
- Temperatures warm slightly Sunday, bringing a risk for a few
  late day and nighttime thunderstorms. Severe weather risks
  remain low.
- Near normal temperatures are likely most of next week, with a
  rather uncertain precipitation forecast through the week.
&&
.DISCUSSION...
Issued at 209 AM CDT Fri Sep 19 2025
THIS MORNING: A large upper trough continues to rotate through
the Dakotas early this morning. An extended mid-lvl trough
pivoting northward this morning will continue to produce an area
of light rain thanks to persistent dPVA. This more extensive
area of rain will likely stay east of I-29. A second area of
even lighter showers to sprinkles is tied to a 925:850 mb
trough centered west of the James River but pivoting east
northeast. Areas of fog are also expected within a narrow
corridor near or east of this low-lvl trough. Visibilities may
drop below 1/2 mile along portions of Highway 14 into the
daylight hours.
TODAY:  The upper low wobbles and sinks southeast through the day on
Friday, keeping a fairly persistent light to moderate shower in the
Tri-State area through the day. While severe storms are not
expected, a cluster of CAMs all indicate some increased NST and
stretching parameters extending along a northeastward pivoting
surface boundary by early to mid afternoon. So should a small amount
of instability build, a few funnels may form within the redeveloping
showers.  The area most likely to be impacted would be along and
northeast of a Huron to Madison to Spencer line.
TONIGHT: Quite a bit of cloud cover is likely to linger through the
night.  After a cool day in the 60s, a gradual diminishing of echoes
should begin by the evening with a few lingering sprinkles/showers
tied directly to the upper low core.
SATURDAY: The aforementioned upper low pivots east of the area
towards Wisconsin on Saturday.  In it`s wake, very light flow and
lingering moisture, combined with some self-destructive CU, could
lead to a few afternoon sprinkles.  High temperatures warm slightly
from Friday, but remain near to slightly below normal.
SUNDAY: A broad upper trough remains in place over the Northern
United States into the end of the weekend. A secondary wave within
the trough sinks through the Plains on Sunday.  Warm advection ahead
of this wave could lead to a few Sunday morning showers and
thunderstorms, but lift overall weakens in the afternoon as
temperatures rise.  That said, tall thin CAPE profiles, subtle mid-
lvl wedge of dry air, and very weak inhibition could lead to a few
windy showers and thunderstorms by the evening.  This risk could
continue into the overnight hours.
NEXT WEEK: Confidence remains quite low in the forecast for next
week, given a multitude of mid-lvl waves likely crossing through the
Plains and a generally weak flow pattern.  The primary agreement in
model solutions is that another piece of energy dips into the
Central and Southern Plains and becomes mostly cutoff from the weak
flow.  However that`s about where the agreement ends as large scale
differences in timing and location of the upper low continue.  All
that said, confidence rises slightly in the projection of near
normal temperatures through the week. Regarding precipitation
chances, there is really minimal agreement in any guidance.
Ensembles spread PoPs across nearly the entire central United States
by mid-week. At this time, can`t see any strong evidence to deviate
from the NBM guidance.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1030 PM CDT Thu Sep 18 2025
Showers will continue to rotate around an upper level low
through the TAF period, bringing showers mainly to areas east
of Interstate 29 tonight - with lesser chances back to the west,
then from east central SD into southwestern MN on Friday.
Showers are then expected to diminish on Friday evening.
MVFR/IFR ceilings currently west of the James River Valley will
expand eastward overnight, affecting all TAF sites into late
morning/early Friday afternoon. In addition, there will be a
potential for patchy fog formation late tonight into Friday
morning, with the greater probabilities residing from east
central SD through southwest MN into parts of northwest IA.
Light southerly winds will slowly transition to
west/northwesterly tonight into Friday.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Dux
AVIATION...JM

NWS FSD Office Area Forecast Discussion