Area Forecast Discussion
Issued by NWS Grand Forks, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KFGF 131147
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
647 AM CDT Wed Mar 13 2024

.KEY MESSAGES...

- There is a 20 percent chance for a light freezing rain leading
  to a light glaze of ice in the Devils Lake Basin and northern
  Red River Valley near the US/Canada border late tonight into
  Wednesday morning. This may impact the morning commute before
  10 AM.

- There is a 10 percent chance for winter travel impacts between
  Friday night and Sunday morning due to light accumulating
  snow and blowing snow.

&&

.UPDATE...
Issued at 647 AM CDT Wed Mar 13 2024

Radar continues to show light showery returns across eastern ND
and northwest MN, but other than a few reports of very light
sprinkles most activity has remained virga. The lowest
temperatures are ahead of this where skies remained clear in
northwest MN with temperatures generally 33-43 where the light
sprinkles are occurring. The far northern counties in northeast
ND and northwest MN remain areas to monitor the next few hours
as that`s where temperatures are hovering near freezing as
these light showers are moving east. For now impacts (if any)
will remain very localized, but chances aren`t zero through 10
AM (when all locations should be above freezing).

&&

.DISCUSSION...
Issued at 358 AM CDT Wed Mar 13 2024

Today: A mid level shortwave is moving over southern Canada
(circulation in WV imagery near southeast Saskatchewan/US border),
with more diffuse forcing ahead of this across eastern ND and
northwest MN where steep mid level lapse rates are in place.
Regional radars show a lot of showery returns, however a substantial
sub-cloud dry layer (shown on RAP soundings) has been limiting light
precipitation reaching the surface (mainly virga with only isolated
reports of sprinkles). There are some showers with slightly higher
returns that might be capable of brief light accumulations, but
where this activity has been tracking air/surface temperatures have
remained above freezing (34-41F). There is still a window through 10
am where a light shower could occur where surface temperatures are
near or below freezing creating slick travel near the US/Canada
border, but confidence in impacts is low based on current trends.
Ahead of the mid level clouds there has been a shallow saturated
layer and few pockets of dense ground fog, but webcams show limited
impacts in the northern Red River Valley and improvement should occur
as the clouds fill in over those areas.

Friday-Sunday: We are still tracking the evolution of a clipper type
system with all ensemble solutions at this point keeping the
strongest portion of the mid-upper low well east of our region.
There is a subset of ensembles that show a secondary shortwave
possibly dropping south farther west, but this is farther removed
from better moisture advection and isn`t resolved to produce more
than light QPF (0.01-0.05") if it were to occur. There remains
within the ensemble data sets probabilities for 0.25" QPF towards
northwest/north central MN which would be closer to the main upper
low (25%) and if this were snow could correlate to 2-3" snow
amounts considering the wetter/lower snow ratios expected.

Temperature profiles are a complication though as near surface
temperatures are favored to remain above freezing until the stronger
front arrives Saturday (and forcing/moisture aloft is decreasing at
that time). These temperature trends also lower confidence in blowing
snow impacts despite the strong wind signal highlighted by ensembles
behind the front (would need to occur with falling snow).

There is a signal for strong frontogenesis parallel to the frontal
zone and very steep low level lapse rates as the front passes with
upright instability (positive 0-3 KM ML CAPE) in the prefrontal
environment. As would be expected, the snow squall parameter is
positive along/behind this frontal zone raising the potential
for these types of features.

The most likely scenario for this pattern is a light rain/snow mix
and lighter snow accumulations of a dusting to 1" (90% chance).
However, there are reasonable scenarios where either intense snow
showers develop with locally higher rates leading to localized 1-3"
totals (reflected in 24hr ensemble probs in north central MN), or
even snow squall type features bringing brief whiteout conditions as
the front passes Friday night-Saturday morning.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 647 AM CDT Wed Mar 13 2024

VFR conditions are expected to continue through the evening. Winds
will stay between North-Northeast through tonight. By 06z a stratus
deck will move over the Devils Lake Basin with the potential
development of fog. If fog develops KDVL may become IFR (10% chance)
in the early morning but should return to MVFR/VFR shortly after
sunrise.

&&

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

&&

$$

UPDATE...DJR
DISCUSSION...DJR
AVIATION...MM/DJR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.