640
FXUS63 KFGF 230445
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1145 PM CDT Sun Sep 22 2024

.KEY MESSAGES...

- There is a low chance for patchy frost late tonight into
  Monday morning, mainly across portions of west-central
  Minnesota.

&&

UPDATE
Issued at 1002 PM CDT Sun Sep 22 2024

Thinner high clouds continue to stream into the region, but
there are noticeable gaps of clearing. Surface high pressure
has already shifted farther east and south-southeast winds are
starting to develop in ND. Where winds are calm Tds are
generally in the 39-43 range, and as the pattern continues to
shift tonight that will likely be representative of most of the
temperatures in our MN counties where winds remain lighter. A
few lower values still can`t be ruled out in west central MN
(like we saw in the previous morning temps), but that would be
very localized. The general forecast remains on track, so only
minor adjustments were needed.

UPDATE
Issued at 636 PM CDT Sun Sep 22 2024

High clouds are increasing from the west-northwest currently and
adjustments were made to better reflect this in the near term.
Otherwise, forecast remains on track with a window for patchy
frost (low chance) and patchy fog in west central MN (very
localized). "Warmer" temperatures in ND and the RRV of northwest
MN due to increasing winds/mixing late.

&&

.DISCUSSION...
Issued at 240 PM CDT Sun Sep 22 2024

...Synopsis...

Look for a continuation of cooler temperatures through tonight and
into Monday morning as H5 troughing prevails across the central
CONUS. H5 heights begin to increase late Monday into Tuesday as
ridging builds into the area from the west. As this happens, a
shortwave traverses the gradient late Monday evening into Tuesday
morning, bringing a chance for mainly scattered showers across the
area. Warmer temperatures enter the forecast for mid-week, with
widespread 70s to low 80s for highs Wednesday through Friday.

...Patchy Frost Possible Tonight...

There is a 15 percent chance for patchy frost tonight into Monday
morning, primarily in portions of west-central Minnesota.
Temperatures are expected to fall into the upper 30s to low 40s,
with a few cooler spots possible. Further west, look for middle to
upper 40s across much of the central and northern Red River Valley,
as well as the Devils Lake basin.


Scattered Showers Monday evening and Tuesday morning:

Ensemble guidance is in relatively good agreement regarding the
development of a shortwave Monday into Tuesday. As this moves
southeastward, out of southern Manitoba, winds are expected to
increase out of the south to southwest. While there will be some
moisture return, this will be limited by the forward speed of the
system as well as a somewhat unfavorable source region for moisture.
As such, QPF is expected to be rather light, with the best chances
for rain occuring in the Devils Lake area, where there is a 50
percent chance of 0.10 inch or more precipitation. Elsewhere, dry
air at the surface is likely to inhibit much of the precipitation
from reaching the surface, there is generally less than a 30 percent
chance of 0.10 inch or more precipitation for the central Red River
Valley and northwest Minnesota.

Wednesday through Next Weekend:

Ridging prevails starting around mid-week, with a moderately strong
ridge developing and moving into the Northern Plains (H5 heights of
2-3 sigma above average). As a result, temperatures are expected to
be well above average for late September. Precipitation is not
expected Wednesday through Friday. Our next chance for precipitation
will be late Friday night into Saturday morning; however, this will
depend on the development of low pressure in the Southern Plains
late this week. Ensemble agreement is low at this point (20-30
percent of members show development), thus confidence is rather low
heading into Saturday and Sunday.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1145 PM CDT Sun Sep 22 2024

VFR conditions should prevail through the TAF period across
eastern ND and northwest MN. There is still a window for
patchy fog development in west central MN through sunrise, but
there are no indications in guidance of this at this time
(KBJI would be the one TAF site we will monitor based on surface
high position where light winds should persist).

Southerly winds increase above 12kt during the late
morning/daytime period Monday as pressure gradient strengthens
ahead of the approaching low pressure and associated front
(gusts 20-25kt most common in eastern ND). This system is shown
to bring chances for high based light showers (30-40% chance),
with better chances at KDVL Monday evening (less confidence
east).

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...Lynch
AVIATION...DJR