Portland, North Dakota Weather Forecast Discussion

277
FXUS63 KFGF 181724
AFDFGF
Area Forecast Discussion
National Weather Service Grand Forks ND
1224 PM CDT Thu Sep 18 2025
.KEY MESSAGES...
- Prolonged period of showers spreading north today and pulling  out
  Saturday. 70 percent or higher chance of 1 inch or more of  rain
  in southeast North Dakota thru Friday night.
&&
.UPDATE...
Issued at 1225 PM CDT Thu Sep 18 2025
Showers continue lifting north and west this afternoon. Most
activity thus far has been relatively light, with only
occasional moderate showers across the southern Red River Valley
and southeast North Dakota. The forecast remains on track this
afternoon.
UPDATE
Issued at 658 AM CDT Thu Sep 18 2025
Weather is behaving as expected to I see no need for changes to
the grids. Dry slot is working north into northeast SD and under
it are low clouds and some fog. Moisture feed this morning not
great but it is allowing for showers to continue to form in
west central and central MN and move WNW. Next wave near Kansas
City and do look for that wave to spread heavier rainfall into
the area later tonight/Friday.
&&
.DISCUSSION...
Issued at 315 AM CDT Thu Sep 18 2025
...Synopsis...
The focus the next 48 hours will be movement, development of 500
mb low over the N Plains and rainfall amounts. Overall it is not
looking like rainfall amounts spread out over 48 hours will be
enough to cause any impacts in terms of flooding or river
flooding. Impacts due to general wet weather present due to
impacts to ongoing harvest, depending on crop, and also impacts
to outdoor activities.
Early this Thursday morning, 500 mb low is slowly moving south
and near Saskatchewan Montana border and overall in the past day
it has tracked southwest. Meanwhile 500 mb low is seen in
central south central South Dakota with deformation zone
rainfall in south central ND into west central SD. During the
course of the day today as the upper low in Montana/Sask border
region drops south and upper low in South Dakota moves north and
then tonight into Friday eventual consolidation with upper low
in south central or northeast SD. Rain showers will continue to
advance north and then west around the upper low today as as the
upper low in SD moves north there will be a gradual north
advance of showers. Dry slot mid level working up into southeast
and east central SD and southwest MN may move into southeast
fcst area and for a time this afternoon or evening limit
precipitation. But also expect at that time likely lower clouds
and potential drizzle in that dry slot area. There is some 500
j/kg CAPE in the dry slot area near the ND/MN/SD border region
at 00z so a few t-storms are possible. I dont foresee any
strong or severe storms. Anytime you have an upper low nearby
having a brief funnel cloud isnt unusual.
Models in agreement in taking a separate short wave in Kansas
early this morning northeast into western Iowa and then
northward tonight into Friday, and with this will be a surge of
deeper moisture and increased rainfall rates spreading into the
area later tonight into Friday.
Upper wave does seem to be more northeast now into NW Ontario
with showers Saturday focused in northern MN into NW Ontario
and eastern Manitoba. Rain chances may linger into Sunday in
north central MN.
Next week is indicating an upper trough moving into B.C. with a
broad upper ridge building into south central Canada and north
central US on the north side of an upper low Tues-Thu period.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1225 PM CDT Thu Sep 18 2025
MVFR to IFR conditions prevail at most sites this afternoon as
an upper low continues to approach the area. Scattered showers
and perhaps an isolated thunderstorm can be expected through
much of the TAF period, with northeast winds at 10 to 15 knots.
Heading into Friday morning, LIFR ceilings are possible as the
upper low slowly moves closer to the area, bringing low stratus
and BR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Lynch/Riddle
DISCUSSION...Riddle
AVIATION...Lynch

NWS FGF Office Area Forecast Discussion