814
FXUS63 KFGF 151755
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1255 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- Severe risk 1 out of 5 over parts of northwest Minnesota and
  eastern North Dakota Monday late afternoon and evening.

- Threat for heavy rain this week.

&&

.UPDATE...
Issued at 1255 PM CDT Sun Sep 15 2024

Getting a decent amount of stratocumulus clouds across portions
of the Red River Valley into northwestern Minnesota. Satellite
and web cams show fairly flat other than around Marshall county
where there is a bit more depth. SPC has some SB CAPE in that
area, although shear is nil, so will have to keep an eye out and
see if anything develops.

UPDATE
Issued at 943 AM CDT Sun Sep 15 2024

Showers have mostly moved northeast of our area, although some
clouds linger in portions of western Minnesota. Adjusted POPs
and sky grids to reflect current trends. Otherwise pretty quiet
this morning with south winds and temps in the 60s and low 70s.
Temps still seem on track to top out in the 80s.

UPDATE
Issued at 650 AM CDT Sun Sep 15 2024

Shower area progressing as expected with rain showers Grand
Forks to north of TRF attm. Still showers to exit by 15z. Did
add in some low pops for a cluster of showers that formed near
the ND/SD/MN border area moving northeast toward Fergus Falls.

Otherwise no need to alter temps, wind or sky attm.

&&

.DISCUSSION...
Issued at 341 AM CDT Sun Sep 15 2024

...Synopsis...

500 mb southwest flow will be over the area this week. This
will bring unsettled weather with periodic chances for showers
and thunderstorms. Very moist environment with dew pts in the
60s to low 70s (locally higher) will mean potential for heavy
rain where storms develop and track over the next 7 day period.

...TODAY....

850 mb warm and moist advection over the area tonight into
Monday morning. With this is an area of elevated instability and
a weak short wave moving into east central ND at 08z. Small area
of showers (and at times isold thunderstorms) in between
Jamestown and Grand Forks moving northeast. This activity will
move northeast and exit NW MN by 15z according to latest HRRR.
So used that timing for the grids.

Otherwise clearing will work in today and the afternoon should
see a good deal of sun for eastern ND at least with lingering
cloud cover in MN.

Dew pts to increase today into the upper 60s over the mid and
southern Red River valley this aftn. Highs will be in the 80s,
with upper 80s possible in the southern valley.

...TONIGHT AND MONDAY...

Various short term models develop some scattered showers in an
area from Bemidji to Fergus Falls this evening with potential
for a few storms. Looks to be along a weak surface boundary.
Confidence on this occurring is low attm.

Higher confidence is that a short wave will move northeast from
western South Dakota into central ND by 12z Monday.
Thunderstorm development is likely to occur near the Missouri
River tonight in area of 850 mb jet of 35 kts and in an area of
elevated instability. A complex of storms may form and move into
parts of northeast ND Monday morning, with chances along the
Intl border thru the day. Meanwhile south-southeast sfc winds to
pick up over SE ND into WC MN Monday aftn with dew pts rising
into the low 70s potentially and what appears to be a weak
surface boundary setting up between the cooler air with
potential storminess north and the hotter airmass south.
Consensus of most 00z guidance is to have a weak sfc boundary in
the Roseau-Grand Forks-Cooperstown area and if this would occur
there could be a pooling of dew pts and therefore higher CAPE
along it. SPC mentions this has a potential area for severe
t-storm development in the late aftn/eve. A lot has to come
together to support this and but if model data is correct I
could see severe storms as SPC mentioned. 00z HREF has some UH
tracks just north of the sfc boundary GFK area late in the day.
SPC has marginal risk for area near the frontal boundary.

...Tuesday and beyond...

There will be an unstable airmass with rich low level moisture
thru the week into next weekend. One upper low will move into
Saskatchewan Wednesday and a potential sfc trough moving into
the area then with t-storm chances and then potentially another
500 mb system more in our local area for the weekend. Threat for
heavy rain is present in this pattern and may end up being the
main hazard to mention.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1255 PM CDT Sun Sep 15 2024

Stratocu has brought some MVFR ceilings to KFAR and KTVF, and
right to the edge of KGFK. This will continue for a good chunk
of the afternoon and then should dissipate around sunset. Could
see a few showers and thunderstorms develop around KBJI around
00Z, with enough confidence to put in some VCTS but not
prevailing. Additional convection could move into northeastern
ND from the west later tonight into tomorrow morning, but less
confident in placement of that activity so will leave out of the
TAFs for now. Winds will shift from their current southwesterly
direction and become light and variable, then pick up again out
of the southeast at 10 to 12 kts.

&&

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

&&

$$

UPDATE...Riddle/JR
DISCUSSION...Riddle
AVIATION...JR