966
FXUS63 KFGF 132020
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
320 PM CDT Tue Aug 13 2024

.KEY MESSAGES...

-Showers and thunderstorms are likely late Wednesday into
 Thursday, with lightning and locally heavy rainfall being the
 main impacts.

&&

.DISCUSSION...
Issued at 315 PM CDT Tue Aug 13 2024

...Synopsis...

Low pressure system continues to develop over eastern Montana this
afternoon, with preceding showers moving through North Dakota.
Strong moisture return ahead of the low pressure and warm air
advection will continue to translate eastward as we progress into
Wednesday and Thursday. Current Satellite shows an expansive area of
cumulus development that is diurnally driven. This should diminish
and help increase ceilings later this evening and into the overnight
period. Hazy conditions will be possible today and into Wednesday as
high level smoke from the western United States shifts eastward
across the area. General flow aloft will be zonal through the rest
of the week bringing chances for shortwaves to shift through the
region. After the work week, we start to see a slow shift in the
pattern flow as ridge begins to intensify in the southwestern and
western United States.

...Showers and thunderstorms Wednesday through Thursday...

Our next chance for precipitation comes Wednesday into Thursday as
the low pressure over Montana translates eastward into North Dakota
and Minnesota. As this happens, warm air advection surges into
eastern North Dakota and northwestern Minnesota along with moisture.
PWATS reach up into the 1.5 to 2 inch range. An axis of strong theta-
E sets up in central North Dakota and into portions of the Devils
Lake Basin and Sheyenne River Valley. This is where we suspect a
boundary to become stationary Wednesday and in Thursday.
Thunderstorms develop along this boundary and the probability of
seeing locally heavy rainfall exists along said boundary. This would
be due to back building and training thunderstorms. Locally heavy
rainfall of 1.5 inches or higher will be possible (20-30% chance)
within the Devils Lake Basin through the Sheyenne River Valley
Wednesday through Thursday. There is a conditional threat for severe
thunderstorms Wednesday afternoon, but environmental parameters of
shear and instability are weak across the western Devils Lake Basin
through the Sheyenne River Valley. None the less, there is a chance
for stronger storms over those areas Wednesday afternoon, with small
hail and brief gusty winds being the main impacts.

Rain will gradually shift eastward Wednesday night and into
Thursday. The low pressure system becomes very progressive in its
movement toward the Great Lakes Thursday afternoon and Friday, but
lingering showers and isolated thunderstorms will still be possible
across the region. Our best chances for dry conditions will be over
the weekend as the system moves east of the area and ridging
develops out west bringing northwesterly flow. Further precipitation
chances are possible next week, but confidence is low at this time.
Temperatures will be seasonal over the next several days, with highs
in the upper 70s to lower 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1246 PM CDT Tue Aug 13 2024

Cumulus continues to develop across the TAF sites this afternoon
bringing BKN cloud coverage. MVFR ceilings are starting to
develop underneath the BKN clouds. DVL is already experiencing
MVFR ceilings, while GFK, TVF, FAR, and BJI will start to see
MVFR ceilings around 19-21z. Clouds will be diurnally driven
and around 01-03z ceilings will start to improve along with
cloud coverage. Chance for showers start to increase this
afternoon in the DVL region, with increased coverage end of the
TAF period. Chance for Thunderstorms at the end of the TAF
period for the Devils Lake Basin.

&&

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

&&

$$

DISCUSSION...Spender
AVIATION...Spender