974
FXUS63 KFGF 152330
AFDFGF

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

.KEY MESSAGES...

- Storms will arrive in the Devils Lake Basin and northern Red
  River Valley late tonight. They will be weakening as they move
  east, but a few isolated storms could still produce hail to
  quarter sized and 60 mph gusts.

- A few isolated storms could develop in northwestern Minnesota
  Sunday afternoon and produce ping pong ball sized hail and 60
  mph winds before quickly moving east.

- Additional thunderstorms will move into southeastern North
  Dakota and west central Minnesota late Sunday night and
  continue into Monday. A few isolated storms could again bring
  some quarter sized hail and 60 mph winds gusts, but the main
  impacts with this system will be heavy rain and flash flooding
  into Tuesday.

&&

.UPDATE...
Issued at 630 PM CDT Sat Jun 15 2024

Strong to Severe Thunderstorms are affecting areas in Cavalier
and Towner counties this evening. This is co located to the
location of the warm front, with strong surface vorticity and
high instability. Sfc to 6km shear is 25-30kts, while low level
sfc to 3km shear is less than 20kts. These storms will continue
to build eastward over the next several hours along the theta E
gradient. Further development later this evening and into the
overnight period as development increases in central North
Dakota.

&&

.DISCUSSION...
Issued at 316 PM CDT Sat Jun 15 2024

...Synopsis...

Southwesterly flow throughout the period sets up an active
pattern for the Northern Plains, with a bit of a break
currently. Main upper trough out over MT tonight will lift into
Canada and help push a surface trough into the Red River Valley
by tomorrow morning. Our western counties currently have some
decent ML CAPE developing but the effective shear is around 25
kts or less and there is little forcing until later tonight when
the trough approaches. HRRR and other CAMs have been fairly
consistent on not bringing storms into our northwestern counties
until late tonight, most likely after midnight. There will be a
weakening trend, but HREF still has some good updraft helicity
tracks still moving into the Devils Lake basin into the northern
RRV. Overall, no changes to the messaging for severe weather,
but did adjust to highlight later timing.

Tomorrow, there is some differences in how far east the trough
axis moves before peak heating hits, with a few of the CAMs
breaking out strong to severe cells in our far eastern counties.
Most of the HREF UH tracks are right along or just east of our
CWA border, but cannot rule out a quick hail report up to ping
pong ball sized and 60 mph winds before it is DLH`s problem. The
bigger issue Sunday night will be with a shortwave lifting from
the southwest into the eastern Dakotas, with surface low
pressure developing to our southwest. A boundary will push north
into our southern counties, and there is some question of how
far north it will get. There is a good chance for some elevated
instability Sunday night and into Monday as this boundary hangs
around the area, with quarter sized hail and 60 mph winds still
the main threats. However, with the 850mb jet bringing lots of
moisture and PWATs nearly 3 to 3.5 standard deviations above
normal, the main issue for Sunday night into early next week
will be heavy rain. Set up for storm motion is also parallel
along the frontal boundary which will be ideal for training.
Probabilities of over 3 inches are over 50 percent in many
locations in west central MN, and probs for over 4 inches are
over 20 percent, which is high chances for that much rain. WPC
has upgraded the excessive rainfall outlook to moderate, and
will upgrade messaging. The main surface trough will be moving
out on Tuesday, and much will depend on how Monday plays out but
with at least some instability and plenty of moisture, heavy
rain and severe potential will continue until the system finally
pushes out Tuesday night.

There should be a bit of a break with surface high pressure on
Wednesday, but active pattern continues for the end of the week
and into the weekend with southwesterly flow continuing and
additional shortwaves coming through. Additional rainfall could
cause impacts given how much is expected early in the week, but
predictability is low for placement of greatest rain amounts as
well as strength of storms at this point. Thus, will focus on
the more immediate concerns.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 630 PM CDT Sat Jun 15 2024

Winds are decreasing slowly this evening for all TAF sites, but
we continue to see GFK, DVL, TVF, and BJI gust up to 30kts.
Around 02-04z winds should diminish as we loose day time
heating. A cluster of strong to severe thunderstorms are moving
through portions of the Devils Lake Basin this evening, but
should remain toward the north of the DVL TAF site. There is a
chance for VCTS as the storms move east. Better chances for
-TSRA are around 6z-12z as further development of storms are
 expected out to the west. As the storms move through the
 region, winds will shift toward the west. This happens mid to
 late morning tomorrow, with gusts up to 25kts possible for TVF,
 DVL, and GFK 18z through the end of the TAF period. Ceilings
 drop to MVFR and isolated IFR 04-06z through 12-15z. Ceilings
 improve west to east.

&&

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

&&

$$

UPDATE...Spender
DISCUSSION...JR
AVIATION...Spender