Area Forecast Discussion Issued by NWS Grand Forks, ND
000
FXUS63 KFGF 091749
AFDFGF
Area Forecast Discussion
National Weather Service Grand Forks ND
1249 PM CDT Fri Jun 9 2023
.UPDATE...
Issued at 1249 PM CDT Fri Jun 9 2023
Cold front moving through southern Canada. Some very strong cells
going near the Manitoba/Ontario border, but also getting some
towers with ice developing in southern Manitoba closer to our
counties. Some widely scattered showers and thunderstorms have
developed across the area ahead of the front in the unstable (ML
CAPE of 2000 J/kg) uncapped air. Deep layer bulk shear is not
impressive but effective shear is around 30 kts, so can`t rule out
some strong to severe storms with an isolated quarter hail or 60
mph report as we head into the afternoon. Most of the haze has
mixed out for the moment over our area, but some high or even
surface level smoke will be possible as the cold front comes
through.
UPDATE Issued at 951 AM CDT Fri Jun 9 2023
Adjusted POPs for a few lingering rain showers over the Devils
Lake Basin and southern Red River Valley. Those locations will see
a few sprinkles this morning. Still think more impactful showers
and storms will be later this afternoon into tonight as a cold
front drops down. Will have to watch what happens with the smoke
as the front come into the area also. Winnipeg observation already
down to 5 miles in smoke and a couple of spots in the northern
RRV showing some HZ. Still think the best high and low level smoke
will be a bit later, but will take a look to see how models are
performing with current observations.
UPDATE Issued at 716 AM CDT Fri Jun 9 2023
Scattered showers linger within the Valley and eastern North
Dakota, and will continue to linger through the morning, favored
in the southern Valley mid to late morning.
First light on visible imagery reveals a thick plume of smoke
draped over the majority of southern Canadian Prairie Provinces.
This lends credence in smoke moving into our area behind the cold
front later today/tonight. There still remains questions on how
much of this smoke is near the surface that would advect into our
area, so still opting to omit from the forecast. However, smoke
aloft moving into our area still remains very confident.
There is a small area of dense fog near the Turtle Mountains and
surrounding area, including into portions of Devils Lake basin
like Towner County. Will monitor trends for it to either expand
and linger further into our area this morning, or if it dissipates
in the next hour or two, with the former resulting in a potential
headline.
&&
.SHORT TERM...(Today through Saturday)
Issued at 333 AM CDT Fri Jun 9 2023
Key Messages:
- Another afternoon of scattered thunderstorms are forecast today.
There is a low but present chance a few storms may briefly
become severe bringing hail up to size of quarters and 60 mph
wind gusts.
- Cold front passes through the area this evening into tonight
ushering in drier and cooler conditions, as well as breezy winds
up to 30 mph.
- Smoke will re-envelope the area behind the cold front tonight
lasting through at least Saturday.
Discussion:
Through the morning, scattered showers from yesterday evening`s decaying
thunderstorm complex will remain possible through sunrise, with
lingering cloud cover through the morning mainly in the south.
Higher than average moisture content and rain-cooled air will
allow some patchy fog to develop through sunrise, mainly west of
the Red River Valley.
This afternoon, clouds are expected to advect away and/or
dissipate allowing for yet another day of convective temps into
the mid to upper 80s being realized. There is a difference in
today compared to previous days, however. This comes in the form
of a notable cold front dipping south out of Canada ahead of a
shortwave trough moving through MB/ON. This cold front will help
spark scattered thunderstorms, best chance this afternoon into
evening between 3-9 PM. Weak to moderate instability is forecast
ahead of the front, with increasing winds aloft presenting at
least 20 kt of unidirectional shear within the storm environment.
Latest high resolution guidance has some differences in magnitude
of shear, but should storms tap succumb to its influence to
organize updrafts, a few storms may briefly become marginally severe
with hail up to the size of quarters and winds to 60 mph. A tell
tail sign storms may be trying to organize will be the tendency
for storms to split and perhaps favor a left-split given the
unidirectional shear with backing winds aloft.
Behind the front, a much drier air mass advects into the region.
The cold air advection and increasing pressure gradient will help
increase winds by Saturday afternoon into the 20-30 mph range out
of the north to northeast. Additionally, there is high confidence
in smoke from wildfires in Canada accompanying the front as well
as trailing behind it through at least Saturday. Most guidance has
this smoke aloft, although some hold varying degrees of smoke at
the surface. Opted to omit smoke within the forecast, but that
could change as confidence increases in thickness of smoke near
the surface. Cooler temperatures within the newly advected air
mass are also expected Saturday with highs remaining in the 70s.
.LONG TERM...(Saturday night through Thursday)
Issued at 333 AM CDT Fri Jun 9 2023
Key Messages:
- Trend for drier, relatively cooler conditions behind tonight`s
cold front will linger through the weekend.
- Another warming trend with additional chances for thunderstorms
comes mid to late next week.
Discussion:
The shortwave trough driving tonight`s cold front is forecast to
strengthen over the Great Lakes over the weekend. This should help
advect drier, milder air mass into our area from Canada. This also
will continue the chance for smoke from wildfires in Canada
(sourced from BC, AB, SK, and now western ON) to envelope our
region perhaps through the weekend into next week.
Ensembles generally agree the upper trough over the Great Lakes
stalls and slowly advects eastward. Eventually its influence over
our area will wane giving way to influence from upper ridging over
central Canada. This will help reintroduce warming temps mid to
late next week. However, ensembles differ on evolution of upper
troughing out of northwestern CAN driven by differences regarding
a Pacific jet out at its base. This trough will dictate how the
upper ridging will break down into late next week, with most
ensembles showing upper height falls over the Northern Plains
which would serve to increase tendency for ascent/convection.
Details beyond a general increase in chance for showers and
thunderstorms remains unclear, although at this time Thursday into
Friday is favored timeframe offered by ensembles.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1249 PM CDT Fri Jun 9 2023
Scattered showers and thunderstorms ahead and along a cold front
that will be dropping into the forecast area this afternoon and
evening, so have VCTS at most airports. Think that most sites will
remain VFR, but could see some brief reductions to visibility if a
cell directly impacts the airport. Probabilities of this are not
high enough to include even in a tempo group at this point. Behind
the cold front, winds will shift to the north and northeast,
although there will be some smoke getting mixed down to the
surface. Could see some lowered vis around 3-5SM during the early
morning hours after the frontal passage. Think smoke conditions
should improve by later in the morning, so have VFR conditions
returning after 12Z. Winds will be fairly breezy behind the front
with gusts over 20 kts from the northeast.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
SHORT TERM...CJ
LONG TERM...CJ
AVIATION...JR