944
FXUS63 KFGF 030306
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1006 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.

&&

.UPDATE...
Issued at 1006 PM CDT Sun Jun 2 2024

Expanded the watch into Wilkin and Grant and ran the whole area
until 11pm for now for the line to work its way southeastward
through the southern forecast area. Starting to get into less
instability, but shear remains strong. Shear gradient and
moisture inflow should allow the line to continue its work
southeast out of the forecast area in the next hour or two
ending much of the widespread severe threat across the forecast
area. Some light showers or weak thunderstorms will still be
possible in the eastern half of the forecast area until the cold
front pushes through later tonight.


&&

.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
UPDATE...MJB
DISCUSSION...JR
AVIATION...JR