027
FXUS63 KFGF 220403
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1003 PM CST Thu Nov 21 2024

.KEY MESSAGES...

- There is a low chance for patchy fog tonight where cloud cover
  is minimal.

- Accumulating snow is possible Saturday through Monday, mainly
  along and north of Highway 200. There is a 60 percent chance
  for 2 or more inches of snow along the International Border,
  with a 40 percent chance along the Highway 2 corridor.

- Much colder temperatures are expected next week.

&&

.UPDATE...
Issued at 1002 PM CST Thu Nov 21 2024

The air mass remains very dry to the west (single digit Tds) and
where there has been clearing temps have fall to the 9-15 range.
Additional drops would be expected, however upstream cloud
cover is starting to approach which will start to fill in from
the northwest later tonight. I made some adjustments to lows to
account for current/expected trends. There is still a signal
for fog development in northwest MN where better BL moisture is
in place, though stratus may tend to limit radiational cooling
and coverage of any dense fog is more uncertain as a result. Due
to the drier air to the west where clearing is in place fog
would tend to be shallower/ground fog "if" it formed. I am still
keeping fog mention in NW MN where the more consistent signal
is.

UPDATE
Issued at 720 PM CST Thu Nov 21 2024

Low stratus continues to linger in our east, with decreasing
winds and mostly clear skies in the west. Temperatures are
already in the lower teens and where skies remain clear colder
spots may fall to the single digits before sunrise Friday.
Eventually guidance shows upstream mid/high clouds filling in so
it`s hard to say how long the clearing will last. This will
also impact whether we have any radiational fog development.
During this update I made near term adjustments and added
patchy fog mention in MN where guidance has been a bit more
consistent in showing potential for fog development later
tonight/early Friday along the western edge of the current
stratus.

&&

.DISCUSSION...
Issued at 333 PM CST Thu Nov 21 2024

...Synopsis...

Shortwave ridging builds into the area tonight into Friday, bringing
warmer 850mb temps into the Northern Plains. The combination of
light winds and increasing moisture levels will give us a chance to
see either low stratus or patchy fog, especially in areas where we
have snow on the ground combined with clearing skies. At this time,
there is roughly a 15 percent chance for visibility lower than 1
mile early Friday morning.

Generally quiet weather prevails Friday into early Saturday as the
ridge moves across the area and then into the Upper Midwest. Daytime
high temperatures will struggle to climb out of the mid to upper 20s
across much of the area both days.

Accumulating snow is possible once more this weekend, starting late
Saturday afternoon for portions of the Devils Lake Basin, then
working slowly eastward. This will be in response to an upper low
moving across the southern Canadian Plains, with the resultant
trough extending southward into North Dakota and northwest
Minnesota. Ensemble guidance has been coming into better agreement,
with a slight shift southward compared to previous runs. At this
time, there is a 60 percent chance for 2 or more inches of snow
along the International Border late Saturday through early Monday.
Further south, along the Highway 2 corridor, there is a 40 percent
chance for 2 inches of snow. The 25th and 75th percentile spread
generally indicate a range of 1 to 4 inches; however, the track will
ultimately determine where the higher amounts can be expected.

Heading into next week, much cooler temperatures settle into the
region. Look for high temperatures in the teens to low 20s with lows
in the single digits to low teens. Impact chances look minimal
Monday and Tuesday, with ensembles picking up on potential activity
Wednesday through Friday. At this time, consensus is rather weak,
thus confidence is low regarding wintry conditions over Thanksgiving
and into Friday and the weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 540 PM CST Thu Nov 21 2024

Low stratus associated with IFR ceilings (some pockets of LIFR)
continues to linger over northwest MN, with impacts to KTVF and
KBJI. Latest guidance keeps this just east of KGFK/KFAR through
the TAF period, with VFR now favored based on current trends.
However it could be close much of the night into Friday morning,
so there is still a low chance for MVFR to IFR impacts at those
sites. In addition, where skies are mostly clear radiation fog
may develop, though the signal for most areas is very
spotty/weak, and predictability at TAF sites will be low. The
best chance for any visibility impacts is a bit higher in MN
based on a consensus of models and I kept a mention of light fog
(3-6sm) at KBJI after 05Z. All guidance supports VFR returning
to all sites where stratus/fog lingers Friday by the afternoon
period.

Surface high pressure continues to build over the region and
west-northwest winds are rabidly decreasing and should become
calm or light and variable (under 5kt). A weak gradient
developing behind this initial surface high will allow winds to
prevail 5-10kt from the west-southwest Friday afternoon.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

UPDATE...DJR
DISCUSSION...Lynch
AVIATION...DJR