471
FXUS63 KFGF 200448
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1148 PM CDT Wed Jun 19 2024

.KEY MESSAGES...

- Additional chances for thunderstorms and heavy rain are
  possible late Thursday through Saturday.

- Active weather continues early next week, with another chance
  for showers and possibly strong thunderstorms Monday and
  Tuesday.

&&

UPDATE
Issued at 1004 PM CDT Wed Jun 19 2024

Light showers are starting to approaching our south, but drier
air seems to be having an impact and at most a few sprinkles may
be occurring south of I-94. There is a spotty signal for 0.01"
from CAMs in the short term so I couldn`t rule out a few wet
spots overnight into the morning hours over the southern Red
River Valley but impacts will be minimal. I made additional
adjustments for timing out mention of slight chance PoPs in our
south through the night in our south, otherwise forecast remains
on track.

UPDATE
Issued at 631 PM CDT Wed Jun 19 2024

Virga or a few sprinkles may develop in far southeast ND and
west central MN late tonight, but measurable chances remain
less than 15 percent for most locations. I made some adjustments
for the mid level clouds starting to spread into the south,
otherwise the forecast is on track.

&&

.DISCUSSION...
Issued at 310 PM CDT Wed Jun 19 2024

...Synopsis...

The high pressure system has remained over Central North Dakota
today relatively suppressing any cumulus development closest to the
low. However, low level cumulus has gradually increased east of the
Red River where more low level moisture was trapped under the high
pressure system meandering through our area. This area of high
pressure will slowly move off to the east tonight as a 700mb
moves through the northern plains and increases brief
precipitation chances for areas south of I-94. CAM soundings
show the lower levels drying out by this evening so its
uncertain if these light showers will reach the ground or remain
as virga.

Thursday afternoon into the evening a warm front will produce
more Thunderstorm chances for the area. The axis of development
for this precipitation event looks to be lighter for our area
than past events. Precipitation totals looks to to be between
0.5 to an inch by the South Dakota Border, and less than 0.25
inches North of the I- 94 corridor. MUCAPE ahead of the
shortwave could be upwards of 2000 J/Kg according to model
soundings, which could support a mention of isolated strong to
severe thunderstorms, which would likely be elevated due to the
overall lack of surface based instability. Shear in both the
0-3Km and 0-6Km layers are supportive of large hail and damaging
wind gusts.

Friday through Wednesday:

Continued warm air advection and a low level jet in conjunction with
a shortwave will provide forcing for elevated convection Friday
night. At the nose of the low level jet in the far southern FA, CAPE
values Friday evening into the overnight are around 1000 J/Kg with
favorable shear. Therefore, the main hazards would be large hail and
damaging winds. Due to the elevated nature of the storms, the
tornado risk is very low. Currently, the better instability is
progged to reside south of the area. Therefore, the SPC has placed
our extremely far southern FA under a marginal (level 1 of 5) risk.
This threat appears conditional on the track of the surface low. If
the low tracks further south, the best instability may stay entirely
south of our area. Further north, the chance for at least a few
isolated elevated severe thunderstorms increases. Heavy rain
however will remain a threat with any thunderstorm that develops.
While not stationary, storms will travel slowly, resulting in the
potential for locally heavy rain. Probabilities of at least an inch
of rain are 80% in the southern Red River Valley into west central
MN. Probabilities drop quickly to the north.

As we work into next week, a progressive pattern will set up over
the region. Several shortwaves are expected to propagate through.
The first wave arrives Monday, providing a chance for severe
thunderstorms. Shear vectors are favorable for discrete storms.
Probabilities Monday afternoon of CAPE values of at least 2000 J/Kg
are 70% across our southern counties. The fine details that will
determine the eventual setup for severe weather such as the
orientation of the wave and exact timing are too far out to
determine. However it will be a period worth monitoring for strong
to severe weather. This active pattern will continue beyond Monday
as more waves propagate through the region, with models currently
having a poor handle over each waves specific strength and
timing.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1148 PM CDT Wed Jun 19 2024

VFR conditions should prevail through the TAF period, though
there is a low (less than 10%) chance for ground fog development
early Thursday morning if skies remain clear overnight. Surface
high pressure remains in place, resulting in calm or light and
variable winds (5 mph or less) through Thursday morning. Weak
gradient begins to build ahead of low pressure and southeast
winds prevail 5-10kt during the day Thursday. A few
sprinkles/light showers or virga may move over southeast ND and
west central MN through Thursday morning. Better rain chances
(and thunderstorm chances) arrive later Thursday night after the
current TAF period.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...MM/Rafferty
AVIATION...DJR