681
FXUS63 KFGF 141527
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1027 AM CDT Fri Jun 14 2024

.KEY MESSAGES...

- General rain with limited chances for severe weather this weekend

- More notable chances for severe weather for the first half of
  the week.

&&

.UPDATE...
Issued at 1026 AM CDT Fri Jun 14 2024

Any lingering patchy fog has since diminished.

Satellite reveals mostly clear skies across much of the Dakotas
into Minnesota under the influence of surface high pressure and
ridging aloft. Fair weather cumulus is starting to develop in
lakes country of Minnesota, which will likely continue to spread
in coverage through the morning into this afternoon.

Getting into this evening, morning guidance still suggests
thunderstorms develop in central North Dakota spreading eastward
tonight as upper ridging shifts east allowing troughing in the
PacNW to impinge upon the northern High Plains, along with
moisture/instability return to feed convection. At this time,
the chance for severe weather is low (less than 10%) with this
activity due to marginal available instability, however shear is
strong. Should storms this evening find better available
instability (potentially through via steeper than forecast
lapse rates aloft), hail would become possible.

UPDATE
Issued at 627 AM CDT Fri Jun 14 2024

Satellite and webcams show a few spots this morning with patchy
ground fog, with otherwise clear skies across the area. Winds
remain calm with temperatures in the 50s.

&&

.DISCUSSION...
Issued at 300 AM CDT Fri Jun 14 2024

...Synopsis...

Low amplitude ridging centered from northern Mexico to the Central
Plains will shift east over the next few days and deepen, blocking
western flow and allowing southwest flow to amplify over the
Northern Plains. This will see increased chances for widespread rain
and numerous chances for severe weather in the Northern Plains
through Wednesday when the stubborn eastern CONUS ridging gives way
and allows for more zonal flow to wrap up next week.

Currently sfc high pressure can be noted shifting east across the
Dakotas and Minnesota with wind becoming light and variable. A lack
of cold air advection or DNVA will likely limit fog formation
without the support of widespread subsidence from aloft but wouldn`t
be surprised to see some localized pockets of fog either. Regardless
low impacts from any fog that does develop with clearing shortly
after sunrise. This evening weak theta-e advection will be the focus
for elevated convection. MUCAPE of 500 j/kg or less will likely only
yield a lightning threat with rain totals being highly variable and
generally under a quarter inch per HREF PMM.

...Weekend Appetizer...

850mb ridge then shifts east into the Great Lakes by Saturday with
an upper trough moving into British Columbia. At the same time a
cold front sweeping through Montana into North Dakota will become
the focus for isolated to scattered thunderstorms Saturday afternoon
reaching eastern North Dakota overnight. Early indications show a
primary wind threat especially as convection trudges east. A
combination of CSU MLP and CWASP paints the highest severe risk
across the Devils Lake basin for our domain aligning well with the
SPC day 2 outlook. MUCAPE of 1000-2000 J/kg and limited bulk shear
atop a nocturnal LLJ aligns well with this picture of upscale linear
growth through the night.

...Severe Threat Continues...

Unfortunately this will likely only be an appetizer as the upper
trough shifts east into the northern Rockies with the stationary
eastern ridging locking us into southwest flow aloft. While guidance
does not show any well defined individual waves moving through the
area to increase confidence on the overall severe threat any given
day the overall pattern of veering winds, gulf moisture, and a plume
of steep mid level lapse rates should point to a continued severe
threat of which the severity will maintain a lower predictability
horizon relying of location of sfc fronts and other mesoscale
details. Currently a marginal risk of severe storms Sunday across
the tri state SD/ND/MN and point east roughly along the remnants of
saturdays cold front. Then a more well defined wave Monday with
better overall thermodynamic and kinematic support to warrant a 15%
from SPC though areal changes are likely this far as guidance gets a
better handle on the pertinent shortwave, a reminder that the parent
trough is still over the Pacific currently where models have minimal
data to ingest and improve the forecast confidence.

While the shiny object in the forecast is likely the severe threat
for most repeated convective rainfall will also yield a flooding
threat. Despite the plethora of rain received in the past 60 days (2
to 4" above average regionally) soils have continued to show at least
some capacity to absorb more moisture which was evidenced in the
blowing dust last week. Thus at least antecedent conditions will
likely limit the overall flooding threat but increased water in
fields and local stream rises appear likely as soils saturate.
Confidence continues to grow for hydro related impacts as ensembles
depict a stalling sfc front in the Northern Plains early next week
with the aforementioned upstream dynamics providing ample support for
heavy rainfall across the region (convective or not).

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 627 AM CDT Fri Jun 14 2024

VFR conditions prevail at all TAF sites this morning, with
occasional ground fog possible around KDVL through around 13Z.
Otherwise, look for clear skies through much of the day with mid
level clouds increasing late this afternoon and evening. Rain
and thunderstorm chances increase overnight; however, confidence
is too low in any single location to mention VCTS at this time.
Winds gradually shift to the south then to the southeast, with
wind speeds increasing into the range of 7 to 12 knots heading
into Saturday morning.

&&

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

&&

$$

UPDATE...CJ/Lynch
DISCUSSION...TT
AVIATION...Lynch