557
FXUS63 KFGF 170435
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1135 PM CDT Mon Jun 16 2025

.KEY MESSAGES...

- Patchy dense fog is expected tonight through Tuesday morning,
  with potential impacts to the Tuesday morning commute.

- Active pattern keeps thunderstorm chances in the forecast
  nearly each day this week. Strong to severe storms are
  possible.

&&

.UPDATE...
Issued at 1135 PM CDT Mon Jun 16 2025

Patchy dense fog (1/4sm or less) is occuring along a line from
Crookston to Thief River Falls to Baudette and a larger area of
1sm is expanding in northwest MN north of Hwy 2. This was not
handled by earlier guidance and only now is being reflected as
the latest short range guidance initializes with current
conditions. Recent rains, and areas of good radiational
conditions will tend to support radiational fog through the
night, but impacts may remain patchy/localized in nature. For
now I issued an SPS through 08Z (3AM) where it is ongoing, as
there is less certainty on coverage/duration, and we`ll monitor
trends overnight.

UPDATE
Issued at 1004 PM CDT Mon Jun 16 2025

There is still enough instability in place in our west to
potentially support a thunderstorm holding together with weak
forcing in west-northwest flow aloft. HRRR and other generally
reflects the current trend of this activity remain west and
weakening with low level lapse rates decreasing locally (post
sunset). With the recent rain and light surface winds
radiational fog may develop where skies remain clear with the
best signal in guidance generally in the southern Red River
Valley (particularly west and east of the valley). Due to
northerly flow there is drier air just off the surface, so the
fog may remain relatively shallow and outside of sheltered
locations in the MN forests impacts may be minimal. I added
patchy fog in the favored period Tuesday morning (09Z-15Z) which
matches timing of NBM and CAMs.

UPDATE
Issued at 647 PM CDT Mon Jun 16 2025

The main mid level wave responsible for earlier low top
supercells and linear clusters has pushed east with only light
rain lingering in our north central MN counties. 925mb CAA and
a period of subsidence is place locally and we are generally
dry except for our east. There are some weaker mid level
impulses upstream in northwest ND, however there is still an
axis of 1000-1500 J/KG ML CAPE and effective shear 30-40kt to
our west support a few stronger updrafts. This activity is far
enough st and mean flow is such that it will struggle to reach
the Devils Lake Basin before sunset/low levels decouple.

&&

.DISCUSSION...
Issued at 339 PM CDT Mon Jun 16 2025

...Synopsis...

Upper level wave lifting through the area responsible for area
of showers and storms impacting the CWA currently. Main
instability axis across the far southeast where current Tornado
watch in place and ongoing thunderstorm activity continues to
lift northeast. A larger westerly flow pattern will continue
with shortwaves moving across the area into midweek with
more isolated storm chances continuing the next few days. A
trough dropping through the northern stream will bring another
wave along the international border bringing the greatest
potential for storm chances later Wednesday into Wednesday
night. A larger trough then to develop across the northwestern
US into the weekend with southwest flow setting up across the
Northern Plains. This will likely set up increasing storm
chances for the weekend.


...Shear profiles and low-topped nature to the
storms indicate mainly a tornado threat or isolated wind gust
threat with any remaining activity through the hour or so
before it moves off to the north and east...

...Continued active pattern with storm chances through the
forecast period. The most organized chances for strong to
severe storms could be Wednesday and again toward the weekend...

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1135 PM CDT Mon Jun 16 2025

Patchy dense fog is impacting KTVF and additional fog may
develop through sunrise Tuesday, though it may remain localized
in impacts in ND. Best chance for fog expansion based on
current guidance is in MN with IFR to LIFR conditions at KTVF
and eventually a period of reduced visibility at KBJI. We`ll
have to monitor trends and amend as needed. MVFR stratus may
also redevelop in MN, with less of a signal in ND at this time.
Light winds eventually increase from the north-northwest
10-13kt after sunrise and combined with daytime heating should
bring a return to VFR conditions to all TAF sites Tuesday.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...MJB
AVIATION...DJR