Casselton, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

953
FXUS63 KFGF 302307
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
607 PM CDT Sun Mar 30 2025

.KEY MESSAGES...

- A winter storm may develop across the region Tuesday into
  Wednesday, with heavy snow and blowing snow impacts Tuesday
  night through Wednesday evening. The highest chance (70%)
  for warning impacts from heavy snow greater than 6 inches is
  from southeast North Dakota into parts of west central and
  northwest Minnesota.

&&

.UPDATE...
Issued at 607 PM CDT Sun Mar 30 2025

There are a couple of things to keep an eye on tonight, wind
speeds and cloud cover. There is a band of clouds that extends
from western North Dakota, up into northeast North Dakota, then
over toward Flag Island in the Lake of the Woods. This band
should continue to sink southward this evening, possibly even
thinning a bit as it does so. Behind this band, skies do clear
out again. The gusty north winds will slowly decrease again this
evening, finally looking fairly light for Monday.

&&

.DISCUSSION...
Issued at 349 PM CDT Sun Mar 30 2025

...Synopsis...

One mid/upper trough is transitioning east of our area over the Upper
Midwest, with westerly flow currently trending towards shortwave
ridging Monday (warming temperatures dry conditions favored).
Southwest flow develops ahead of the next system with an initial
wave Tuesday followed by a stronger mid/upper low Tuesday night into
Wednesday. After that period of potential winter impacts there is a
transition to broad troughing to the northeast and a larger spread in
over our region ranging from split flow to northwest flow.
Additional weaker/fast moving waves may move through the region in
some clusters, but predictability is low and consensus is for dry
conditions to be favored.

...Winter Impacts Tuesday into Wednesday...

The initial period of southwest flow Tuesday bring WAA and good
moisture advection into the region, with an initial shortwave
supporting increasing precipitation chances early Tuesday morning
through the afternoon west to east. Temperatures may remain above
freezing for the daytime period and due to the high solar angle even
if we did see a change over to snow we may see significant
melting/settling. Where chance for accumulation are best Tuesday
will be early morning and late afternoon, particularly in the higher
terrain regions west of the valley and in west central MN. It would
be a slushy snow if it did accumulate (mainly on grassy/elevated
surfaces) lowering impacts. Considering the uncertainty on impacts
during the day Tuesday our greater focus is on the more
organized/stronger synoptic low pressure system arriving Tuesday
night.

Clusters are showing strong agreement in general 700MB low
center/strength, which places our south and east under a favorable
region for deformation banding and heavier precipitation rates.
There are still subtle differences in surface low track (which could
impact temps and wind Wed) and orientation of the 700MB low as it
progresses eastward (duration of banding) which still create some
uncertainty. Good instability is shown to the south and banding may
organize near the TROWL that develops as it transitions over our
area resulting in heavier rates 1"+/hr. EFI values are in the 0.8 to
0.9 and shift of tails of 2 across the southern half of our CWA,
reflecting higher chances for heavier snow. NBM probabilities for 6"+
50-80% across our south and east. Considering those trends,
confidence has increased enough to issue a Winter Storm Watch for
southeast ND and parts of west central/northwest MN Tuesday evening
through Wednesday evening.

Some notes on SLR and wind:

There is a strong signal for higher QPF values of greater than 0.75"
with this event in our south and east, and soundings show deep
riming during the periods of heaviest snow. These are both
indicators of lower snow to liquid ratios or wetter/heavier snow
characteristics. It is hard to get higher ratios that 10:1 when
moisture content is that high due to settling/weight and I accounted
for this in my adjustments.

As this is a hybrid/Colorado low type system pressure gradient will
be the main driver of wind speeds with limited to neutral CAA and
mixing playing less of a role in potential wind speeds. Winds may
occasionally gust to 35 mph, but confidence is low in frequent gusts
35 mph+ necessary for true blizzard conditions. Considering the
temperatures and most likely sustained winds, visibility impact`s are
more likley to be driven by heavier snow rates.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 607 PM CDT Sun Mar 30 2025

Like mentioned in the update section above, will be monitoring a
band of bkn040-060 clouds moving from north to south across the
area this evening, along with decreasing north winds. Once this
band moves through, skies do clear out again. Winds will
decrease this evening, finally looking much lower for Monday.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Storm Watch from Tuesday evening through late Wednesday
     night for NDZ038-039-049-052-053.
MN...Winter Storm Watch from Tuesday evening through late Wednesday
     night for MNZ002-003-009-015>017-022>024-027>032-040.

&&

$$

UPDATE...Godon
DISCUSSION...DJR
AVIATION...Godon