705
FXUS63 KFGF 151742
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1242 PM CDT Sat Jun 15 2024

.KEY MESSAGES...

- Isolated to scattered severe thunderstorms are possible today
  for the Devils Lake area and portions of the northern Red
  River Valley. Impacts could include damaging wind gusts up to
  60 mph and large hail up to the size of quarters.

- Isolated severe thunderstorms are possible Sunday afternoon in
  the southern Red River Valley and west-central Minnesota.
  Impacts are possible and could include strong wind gusts and
  large hail up to the size of quarters.

- There will be another chance for scattered severe
  thunderstorms on Monday, with much of the area seeing the
  potential for large hail and damaging wind gusts. Flash
  flooding is possible as there is support for persistent heavy
  rainfall.

&&

.UPDATE...
Issued at 1242 PM CDT Sat Jun 15 2024

Adjusted cloud cover and POPs a bit for current radar and
satellite trends. Temps still seem on track to top out mostly in
the 70s, with a few spotty 80s where there is more sunshine in
the western counties.

UPDATE
Issued at 1001 AM CDT Sat Jun 15 2024

Showers starting to exit our northeastern counties out through
the Lake of the Woods area, so lowered POPs a bit. Still could
see our southeastern counties get clipped from showers moving
through with a shortwave traveling through MN. However, impacts
at this point look minimal with light rain. Otherwise fairly
quiet with most of our severe thunderstorm potential holding off
until later tonight.

Issued at 745 AM CDT Sat Jun 15 2024

Showers and mainly embedded thunderstorms continue to move
slowly off to the east this morning, with southerly to
southeasterly winds increasing. Temperatures are hovering in the
low to mid 60s with dew points in the upper 50s to low 60s.
Minimal adjustments were needed this update as the forecast
remains on track.

&&

.DISCUSSION...
Issued at 411 AM CDT Sat Jun 15 2024

...Synopsis...

A very active weather pattern continues across the Northern Plains
and into the Upper Midwest through the next several days. Upper
ridging builds into the Ohio Valley and the Eastern Seaboard
starting today, which will continue into the early part of next
week. As this happens, H5 troughing digs into the western Conus,
facilitating a favorable pattern for repeated trough passages along
southwesterly flow into the Northern Plains. Moisture will be able
to flow into the area along strong 850 mb transport winds, with long
fetch gulf moisture working into the northern Mississippi Valley
ahead of our H5 troughs. This will set the stage for active weather
to include strong to severe thunderstorms and very heavy rainfall.

...Isolated to Scattered Severe Thunderstorms Today and Sunday...

Theta-e values continue to climb this morning as mixing ratios are
now in the range of 11-13 g/Kg in central North Dakota. This
moisture will continue working eastward into the Devils Lake Basin
by early afternoon, with SBCAPE climbing upwards of 1500 J/Kg by
late afternoon. Shear in the 0-3Km and 0-6Km layers remain
supportive of discrete cells; however, forcing is expected to stay
west of the area, with remnant strong to severe storms working into
the Devils Lake Basin later in the afternoon and into the evening
hours. Environmental support for discrete cells diminishes as this
happens, with clusters and possibly line segments being the primary
mode heading into late evening. Soundings support large hail up to 1
inch, with a more conditional threat of damaging wind gusts due to
storms becoming elevated during the overnight period.

For Sunday, the theta-e gradient along a lifting warm front will be
our primary driver of potentially strong to severe storms. While
shear in the low levels supports a mention of tornadoes, the better
environment looks to stay south of the area. CAPE still looks
supportive of large hail and damaging wind gusts, however, primarily
for portions of the southern Red River Valley and west-central
Minnesota.

...Scattered Severe Thunderstorms Monday...

A stronger trough is set to bring severe thunderstorm chances back
into area on Monday as moisture continues to stream into the area.
Mixing ratios climb upwards of 14 g/Kg in the southern Red River
Valley with values of up to 12 g/Kg for the central and northern Red
River Valley. This will usher in a conditional threat of severe
storms that could expand across a larger portion of the area. How
much coverage we see will depend on the speed of the theta-e
gradient boundary associated with a push of cooler and drier air
working in from the northwest. Guidance shows a range of solutions
that support anything from elevated large hail producing supercells,
to potentially tornadic cells ahead of the boundary. With the slow
forward movement expected with this system, we could also see a
flash flood risk emerge as training storms could move repeatedly
over the same area. The best chances for impacts, resides in the
southern and central Red River Valley and portions of west central
Minnesota; however, the position of the boundary will ultimately
determine the axis of heaviest precipitation and strongest
thunderstorm potential.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1242 PM CDT Sat Jun 15 2024

VFR conditions, but some MVFR and then IFR as a trough of low
pressure comes into the Red River Valley tonight, starting in
the more western TAF sites this evening and spreading eastward
as the night goes on. Improvement by the end of the period in a
similar west to east direction by mid-day tomorrow. Some
weakening convection coming through, but uncertain how much will
make it to our airports, so just have VCSH at KDVL for now.
Winds will shift from a southerly direction with gusts around 25
kts this afternoon. Decreasing a bit to around 10 kts and going
to a southeast and then southwest and finally west to northwest
as the trough axis moves through by tomorrow morning. Winds will
pick up the the end of the period with gusts to around 20 kts
again.

&&

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

&&

$$

UPDATE...Lynch/JR
DISCUSSION...Lynch
AVIATION...JR