145
FXUS63 KFGF 161820
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
120 PM CDT Fri Aug 16 2024

.KEY MESSAGES...

- Will need to monitor smoke/air quality for any issues late
  today or this weekend.

&&

.UPDATE...
Issued at 1249 PM CDT Fri Aug 16 2024

Slightly adjusted PoPs and Sky grids to account for recent
trends in radar and sfc observations of reported light
rain/drizzle (or lack thereof).

Lessened cloud cover somewhat for northeast ND and northwest MN
as mentioned in previous Update Discussion.

Broadened the coverage of smoke as it enters into the region
this afternoon into tonight based on latest guidance.

Some guidance introduces the chance for weak thunderstorms this
afternoon given the cool temperatures aloft and lessening cloud
coverage leading to some diurnal heating toward convective
temps, although leaving out for now to wait to see how much
heating occurs and whether or not HCR bands mature into
consolidated into one or two convergent bands to help
initiate/focus convection.

UPDATE
Issued at 1024 AM CDT Fri Aug 16 2024

No changes to the forecast were made this update, with previous
discussion points still valid.

Starting to see some indications of sunshine making its way
through scattering clouds in northeast North Dakota, in a
horizontal convective roll-type fashion. This lends some
confidence toward at least northeast ND into northwest MN seeing
this occur by afternoon as moisture lessens and HCR processes
still develop. This in turn lends confidence toward these
locations getting well into the 70s for daytime highs.

There also has been conversation between FGF and MN Pollution
Control on potential adjustments to the Air Quality Alert that
goes into affect this afternoon for near-surface smoke impacting
air quality within the Red River Valley, with main topic about
potential extension given latest smoke guidance lingering smoke
into tomorrow amid the surface high pressure that nestles itself
into our region.

UPDATE
Issued at 647 AM CDT Fri Aug 16 2024

Low ceilings have been persistent throughout the night. With
these low ceilings sporadic mist/drizzle has been falling
on/off at random times and creating lower visibility reports as
well. The models show this light rain/drizzle ending this
afternoon and into the evening.


&&

.DISCUSSION...
Issued at 337 AM CDT Fri Aug 16 2024

...Synopsis...

Sfc low is over Bemidji at 08z with 500 mb low just to its
southwest. Concentrated area of light rain showers moving south
into SE ND and will be into parts of WC MN to start the day
along with areas of drizzle. NE ND/NW MN seeing less in the way
of precipitation to start today. High pressure moves in Sunday
then a slight warm up occurs next week as 500 mb ridge develops
with center over the 4-corners. Short wave moving on top of
ridge will bring t-storm chances Tuesday.


...Today...

Lingering light rain showers over much of the area as upper low
only slowly moves east. Higher pops to start the day into far SE
ND into WC MN (Fargo-Wahpeton-Fergus Falls) as this area will
see the most concentrated showers thru 13z. But upstream radars
do show a few showers yet over western parts of NW Ontario that
will likely move south-southwest thru the area today. Far NW
fcst area likely to remain dry....west of Langdon-Devils Lake.
Just went shower mention and no thunder for now. Not impossible
some weak thunderstorms could form if some cloud breaks will
occur. High temps today in the upper 60s to mid 70s. Light rain
showers may linger into this evening with some model consensus
in showing lingering showers from Roseau to Detroit Lakes this
evening so did keep a low pop in that area.

Looking at wildfire smoke issues...RAP/HRRR, Firesmoke.ca all
highlight the higher concentrations of near surface level smoke
into north central and northwest ND into Montana today with
lighter concentrations into NE ND. MN Pollution Control Agency
issued a air quality alert for the Red River valley of MN for
late today and Saturday, and honestly looking upstream and such
not seeing that degree of smoke push to bring in heavy surface
level smoke. Coord with BIS and used smoke tool and
concentrations of 15 mg/m3 or higher, which pretty much keeps
any smoke west of us. Will let dayshift coordinate any smoke
issues and see how things stand upstream once daylight hits.

...Weekend...
With slow upper low movement Saturday will not quite be as sunny
as prev fcst as likely considerable 850 mb moisture will remain
for CU development. Could even be a stray shower. Sunday will
see sunnier conditions as upper low moves farther east and upper
level ridging begins to move in.

...Next Week...
500 mb trough in eastern Canada and northeast US from the slow
moving upper low affecting us will allow a 500 mb ridge to build
into northern high plains of Montana, southern Saskatchewan
Sunday-Monday and it will build east thru the week. Not as warm
as could be with this ridge, but think low-mid 80s for highs
will be common. One short wave will move on top of the ridge and
give a good chance of t-storms Tuesday/Tuesday night.  GFS prog
MUCAPE of 2500 j/kg 00z Wed supports t-storm potential but 0-6
km bulk shear is 20 kts so on the borderline for any severe
potential. Machine learning info suggests no significant severe
weather threat, with some chances showing up in the high plains
into eastern MT or SW ND where temps will be warmer.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 100 PM CDT Fri Aug 16 2024


Ceiling Impacts:

Lingering aviation impacts from lowered CIGs into MVFR and IFR
categories will continue through at least 21Z for KFAR and KBJI.

Overall, low CIGs behind an exiting low pressure system will
start to scattered out as cloud layer moisture retreats with the
system. There will still be scattered cumulus and shallow
cumulus congestus before 01Z for areas that do lose CIGs.

There is uncertainty in whether or not CIGs return across the
region after 06Z tonight into Saturday morning, although
guidance indicates relatively better chance (60%) for this to
occur within MN, namely at KBJI. For this reason, decided to
maintain MVFR/IFR CIGs at KBJI throughout the TAF period.

Potential Smoke Impacts:

Smoke will spread into eastern North Dakota into the Red River
Valley out of Canada this afternoon into tonight, potentially
impacting KDVL, KFAR, and KGFK. Confidence in vsby reductions
being low enough to present impacts (ie less than 3SM) remains
low, but does remain as a potential outcome after 00Z. For now,
kept vsby reductions at 6SM for now with the anticipation of
updating/amending as needed.

&&

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

&&

$$

UPDATE...CJ/MM
DISCUSSION...Riddle
AVIATION...CJ