235
FXUS63 KFGF 312022
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
322 PM CDT Fri May 31 2024

.KEY MESSAGES...

- Isolated to scattered severe thunderstorms are possible Sunday
  afternoon and evening. Risks could include hail larger than 1
  inch, winds greater than 60 mph, and possibly a few
  tornadoes.

- Additional chances for showers and thunderstorms are in the
  forecast for Tuesday evening and overnight. There is a low
  chance for isolated strong thunderstorms.

&&

.DISCUSSION...
Issued at 322 PM CDT Fri May 31 2024

...Synopsis...

A weak shortwave continues to traverse the Northern Plains today,
bringing only a slight chance for showers and isolated thunderstorms
to areas north of Highway 2. There are minimal chances for severe
thunderstorms today and the most likely scenario supports mainly
embedded thunderstorms; however, a stronger storm or two cannot be
ruled out along the International Border, with small hail and gusty
winds possible this evening. This would be associated with a rather
narrow window where MUCAPE increases to around 1000 J/Kg in the
presence 0-6km shear upwards of 45 knots.

A much stronger H5 trough is set to impact the area on Sunday,
bringing a much better chance for strong to severe thunderstorms.
This will be the next of several shortwaves and troughs rotating
around a large upper low that continues to slowly move eastward
across central Canada. There will be another trough passage heading
into Tuesday afternoon and evening, which could bring another chance
to see showers and thunderstorms.


...Severe Thunderstorms Possible Sunday...

Isolated to Scattered severe thunderstorms are possible on Sunday,
with hazards that could include hail of 1 inch or greater, wind
gusts of 60mph or higher, and possibly a few tornadoes. Storm mode
at this point retains some uncertainty, with a strong dependency on
where initiation occurs. This depends on the forward progression of
the trough axis providing our lift. SBCAPE is expected to increase
ahead of this trough, with a 70 percent chance of 2000 J/Kg or
greater (southern Red River Valley) and an 80-90 percent chance of
1000 J/Kg or greater (central and southern Red River Valley).
Soundings are consistently showing good wind shear at all levels,
with low level shear in the range of 20 to 30 knots and deep layer
shear upwards of 40 knots. Storms are likely to start as discrete
supercells that will quickly become clusters and eventually linear.
In the event of early initiation further west, we would likely see
mainly cluster and/or linear mode for much of the CWA; however, if
initiation occurs later, discrete supercells would impact portions
of eastern North Dakota and bring higher impacts to include golf
ball sized hail, wind gusts of 70mph or higher, and tornadoes.

...Active Weather Continues...

Another, somewhat strong, trough approaches the area late Monday
night into Tuesday. Some ensemble members are developing a negative
tilt as this trough moves into western Minnesota; however the
majority of solutions are showing a more progressive solution. At
this time, it is worth mentioning the possibility of strong storms,
albeit with a lower chance of occurrence. The primary factors
will be the timing of the trough with regards to peak heating,
as well as antecedent cloud cover.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1232 PM CDT Fri May 31 2024

VFR conditions are expected through the TAF period at all
sites. Winds will shift later this afternoon into the evening,
becoming more southerly through the overnight hours. Winds will
shift back towards the west by Saturday mid-morning. Impacts to
aviation are not expected through the TAF period.

&&

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

&&

$$

DISCUSSION...Lynch
AVIATION...Lynch