Area Forecast Discussion
Issued by NWS Grand Forks, ND

Home | Current Version | Previous Version | Text Only | 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 141559
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1059 AM CDT Thu Mar 14 2024

.KEY MESSAGES...

- Snow showers will occur in northeast North Dakota this morning
  through mid afternoon. Periods of reduced visibility under
  half a mile and slippery travel conditions can be anticipated.

- Windy conditions will occur Friday and Saturday. There is a 50
  percent chance for winds to gust as high as 50 mph Friday
  afternoon through Saturday afternoon.

- There is a 10 percent chance for minor winter travel impacts
  between Friday night through Sunday morning due to brief heavy
  snow showers reducing visibility with light accumulations.

&&

.UPDATE...
Issued at 1058 AM CDT Thu Mar 14 2024

Current radar depicts precipitation mostly in the form of
snow within northeast North Dakota and southern Manitoba,
forced by mid level shortwave now centered in southwest
Manitoba. Weak but sufficient instability is mingling with
synoptic forcing to allow for pockets of moderate to heavy snow
rates, with a few webcams and surface observations revealing
this.

With the shortwave forecast to slowly migrate south-southeast
into North Dakota, these snow showers will continue mainly
within northeast North Dakota based on current placement of
forcing/precipitation and expected track of forcing. Because of
the presence of higher snow rates, impacts to travel may ensue
from reduced visibility under half a mile and minor
accumulations generally under 2 inches. There is a 30% chance
accumulations range in the 3-5 inch range for a localized area,
although accumulations would mostly be confined to grassy
surfaces due to the sun`s influence on surface temperatures this
time of year.

Thus, accumulation on roadways may be harder to achieve outside
of heavy snow rates. Despite inefficiency to accumulate,
slippery conditions may still occur should heavy snow rates
reside over an area for more than 1 hour. Regardless of
accumulations, impacts to travel conditions from reduced
visibility can still be anticipated.

Issued at 650 AM CDT Thu Mar 14 2024..

A stubborn cluster of very light showers are tracking across the
central Red River Valley to the southeast. Most air temperatures
are 33-34 where these are tracking, however there are spots that
have fallen to 28-32 particularly ahead of the cluster. Amounts
from these should could vary from a non measurable trace to
0.03" of liquid based on earlier reports. If surfaces are cold
enough, slick spots could develop. After 8 AM short range
guidance supports air temperatures recovering above freezing in
all locations, however before that there is a window for impacts
to the morning commute.

&&

.DISCUSSION...
Issued at 331 AM CDT Thu Mar 14 2024

Large scale pattern shows heights and temperatures aloft falling as
troughing deepens over the Hudson Bay region of Canada placing our
region in north-northwest flow aloft. Eventually flow flattens
into more of a westerly split-zonal type pattern by the middle of
next week. There is a period of impactful weather as the initial
deeper trough moves into the region Friday into the weekend,
otherwise the probability for impactful weather is low. Temperatures
will tend to return closer to "seasonal" ranges this weekend behind
the front, but the progressive nature of weaker waves and evolution
of the pattern next week creates larger spread in potential
temperatures (tendency for above average temperatures most periods
with lack of snow pack in place).

Today: Westerly flow remains in place aloft ahead of a shortwave
trough (currently centered over southeast Saskatchewan). Disorganized
forcing and mid level saturation has helped maintain shower type
precipitation. Due to a sub-cloud dry layer immediately very shallow
BL most of the returns on radar have been virga and where
precipitation has occurred it has not measured (just sprinkles or
flurries). The main shortwave trough drops south through central ND
this morning and HREF is showing a signal for lighter snow
eventually developing which could result in a dusting mainly in the
Devils Lake Basin and west of the Red River Valley through midday.
The track may keep the better forcing/deep saturation west and right
now there is a 20-30% chance for these limited impacts.

Friday-Sunday: There continues to be a good signal in ensembles for
windy conditions and potential advisory winds (gusts 45-50 mph),
especially as the cold front drops south Friday night into Saturday
morning. Deep mixing in westerly flow as gradient increases ahead of
this front could still result in near advisory winds Friday
afternoon, and ensembles show a higher probability along and west of
the valley initially before the front arrives. However, the pressure
rise couplet and CAA with the front could still support good
momentum transfer even into forested areas in MN. Ensembles show
these winds being possible (20-50% chance) across much of our CWA
even outside of the traditional valley as the front drops south
Saturday morning.

Regarding snowfall accumulation and visibility impacts: Over the last
24hr the signal for broad snow accumulations of 1" or greater have
greatly diminished with limited probs for 1"+ of 5% now confined to
the Northwest Angle. However, there is a broader signal for light
accumulation of a dusting (0.1"+) across northeast ND and highest
chances towards northwest MN. This signal aligns well with periods
of instability (steep 0-3km level lapse rates) and the potential for
convective showers to develop. Initially I still can`t rule out
squall type features where progressive parallel frontogenesis could
briefly organized precipitation ahead of the front, but the
evolution of the pattern isn`t ideal and temperatures profiles
questionable early on. Most activity looks like it will quickly
become showery with deep vertical wind shear behind the front within
the saturated adiabatic layer supporting possible HCR type
convective bands/rolls. However the showers evolve, they could
support intense, brief, localized, high rates which could drive
visibilities to near whiteout where they occur.

Those reduced visibilities would be the primary hazard, though a
north to south orientated HCR lingering in one spot could bring
light accumulations 1"+ (duration would matter and probabilities in
ensembles are in the single digits). There remains questions on
coverage (could remain isolated considering the lack of deeper
moisture advection). The precipitation type Friday into Saturday are
also in question due to the initially above freeing lower levels,
and the coldest BL temperatures not arriving until Saturday night
when all locations should finally drop below freezing. The spotty
signal for light shower activity doesn`t end Sunday (though ensemble
measurable snow chances are lower than on Saturday). It is possible
we could continue to see localized impacts continue most of the
weekend (though coverage/location of these impacts remains highly
uncertain). This type of pattern and impacts will carry a low
predictability horizon, so we will have to monitor.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 650 AM CDT Thu Mar 14 2024

There`s some uncertainty with KDVL and its ceiling height.
Conditions may bounce between IFR and MVFR throughout the day.
Some nearby airports are reporting LIFR 200-400ft ceilings
while others are reporting MVFR/VFR conditions. KGFK/KTVF may
bounce between MVFR/VFR in the morning if fog develops. KDVL is
expected to see some flurries this morning while KGFK/KTVF will
see sprinkles both ending by 18z. KFAR and KBJI are expected to
remain VFR throughout the day as the dry layer keeps them from
dropping into the MVFR category. There`s some uncertainty with
tomorrow`s forecast on when the ceilings will lower to
potentially become MVFR/IFR ahead of the system.

&&

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

&&

$$

UPDATE...CJ/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.