611
FXUS63 KFGF 192011
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
311 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.&&

.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 /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1244 PM CDT Wed Jun 19 2024

A low level cumulus field is the main reason for the VFR/MVFR
conditions at all TAFs site except KDVL which is expected to
remain relatively clear because its closest to the surface high.
Around 06z to 09z some brief showers will move from the south
ahead of the warm front however, there is some uncertainty on
how far north these showers will move and may reach KFAR. By
12z these showers will move East and may move over KBJI. VCSH
was placed in the TAFS to account for this uncertainty.

&&

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

&&

$$

DISCUSSION...MM/Rafferty
AVIATION...MM