202
FXUS63 KFGF 022357
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
657 PM CDT Sun Jun 2 2024

.KEY MESSAGES...

- There continues to be a slight (2 out of 5) risk for severe
  thunderstorms this afternoon and evening. Hail up to golf
  balls, wind gusts of 60 mph, and a few tornadoes possible.

- Widespread showers and thunderstorms expected late Monday
  night into Tuesday. Severe storms are unlikely, but some
  impacts from heavy rain as there is a 50 percent probability
  of an inch or more.

&&

.MESOSCALE...
Issued at 656 PM CDT Sun Jun 2 2024

Two main thunderstorm areas of note across the CWA this evening
with the one across the north moving into a worse environment
decreasing instability and bulk deep layer shear. Seeing a small
MCV with it though, so expect some chance for severe
trends could linger for a bit. Stronger storms further south
along the cold front in better environment with stronger
instability and moving into increased deep layer shear around
30-40kts. Strong low level moisture transport into the area with
PWATs around 1.3, and storms training along the boundary.
Currently LL shear more parallel to the storm motion and
boundary, with storm propagation more to the east southeast.
Therefore expect the main threat area for severe weather in the
next 1-2 hours along and south of I-94 across southeastern ND.
Severe threats continue to be large hail and gusty winds,
isolated tornadoes possible as well.

&&

.DISCUSSION...
Issued at 321 PM CDT Sun Jun 2 2024

...Synopsis...

Southwesterly flow aloft with several embedded vorts continues
across the Northern Plains. The main shortwave tonight will push
off into Minnesota and Ontario, pushing the surface trough
currently over the central Dakotas into the Upper Midwest by
Monday morning. This will be quickly followed by the next
shortwave, which will dig into eastern MT Monday night and into
the Northern Plains by Tuesday. Northwesterly flow aloft sets up
to mid to late week and into next weekend.

...Slight risk this afternoon/evening...

Much of the morning and early afternoon has been a lot of non-
severe convection for our forecast area, but starting to get
some stronger cells in the far western counties and there has
been some SPSs and one severe so far. In the last few hours
there has been some more discrete cells developing in south
central ND where there has been some clear skies and ML CAPE of
1500-2000 J/kg. Effective shear is around 30-40 kts, and while
0-1km SRH is not impressive, there has been one rotating storm
just to our west in Stutsman county. CAMs continue to show the
discrete cells moving into southeastern ND in the next few hours
and then merging into a more linear form later this evening.
While there still an isolated tornado threat, mainly in
southeastern ND, the main issue for us will be hail up to
golf balls and then transitioning to winds over 60 mph later
tonight. The storms will push into the MN side, exiting out of
our eastern CWA border sometime around midnight.

...Rain Monday night into Tuesday...

The upper low for the beginning of next week will be fairly
vigorous and our CWA will again be in the warm sector as the
system tracks from the Northern Rockies eastward into Manitoba
and ND. The surface trough axis will push eastward into the Red
River Valley during the overnight hours Monday night. Due to the
timing of the system, the bulk of the forcing will be coming
through during the time of day when we will not be getting good
heating. CAPE values from the ensembles are pretty low, and HREF
has a few paintball UH tracks but not a huge amount. Think
probabilities of severe are pretty low, but we could see some
decent rainfall Monday night into Tuesday as the trough axis
swings through. Probabilities from the NBM are around 50 percent
for over an inch of rain, mainly for northeastern ND but are 10
to 30 percent for other portions of the CWA. With the recent wet
pattern, the rain will have to be watched for impacts.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 656 PM CDT Sun Jun 2 2024

Showers and some storms to impact most sites this evening. KDVL
likely done with majority of the shra/ts activity for the
forecast period. Majority of thunder threat to shift to the
southern and eastern sites as of latest radar trends and best
instability further south, however cannot be ruled out at KGFK
and TVF isolated embedded in the shower activity through 03-04Z.

Frontal boundary to move through late and shift winds around to
the west to northwest with development of low clouds across the
area. CIGS could drop to IFR into Monday.

&&

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

&&

$$

MESOSCALE...MJB
DISCUSSION...JR
AVIATION...MJB/JR