FXUS63 KDLH 172346
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
646 PM CDT Sat May 17 2025

.KEY MESSAGES...

- Frost and freezing temperatures tonight, along with lingering
  scattered light rain/snow showers.

- A widespread freeze is expected Sunday night.

- Cool weather to start next week with rain chances mainly south
  of US-2 and dry weather for much of northeast Minnesota.

&&

.DISCUSSION...
Issued at 311 PM CDT Sat May 17 2025

Plenty of clouds linger this afternoon as low pressure departs
to the east. Shower activity has been sparse, but there are a
few out there. A weaker upper level wave will pass across the
Arrowhead tonight, bringing a better 20-40% chance for light
rain showers. Some snowflakes may mix in late tonight into
Sunday morning, but any accumulations will be limited to a light
dusting at best in the higher terrain of the Arrowhead.

There is some uncertainty on how low temperatures may fall
tonight with plenty of clouds around, but in northeast
Minnesota, anything ranging from around freezing to 36 degrees
is expected. Frost Advisories have been expanded to cover most
of northeast Minnesota, though it is possible that many areas
stuck in the clouds may not see frost tonight. Aside from the
tip of the Arrowhead where a Freeze Warning has been issued, the
next best chance for frost will be around the Brainerd Lakes,
where skies have the best chance of clearing out a bit. Winds
are not expected to calm completely tonight either, which could
keep frost somewhat minimized, but the fact that a colder air
mass is moving in is enough to justify the advisories.

High pressure will settle in up north in Canada going into
Sunday, which will cause winds to become more northeasterly by
Sunday morning. Lingering light showers may persist along the
North Shore Sunday morning as winds switch to northeasterly,
then ending everywhere during the afternoon.

A more widespread freeze is expected Sunday night with skies
clearing out more, especially to the north.

Monday through Wednesday, broad high pressure sets up to the
north in Canada while a potent low passes by somewhere in the
vicinity of the MN/IA border. Track differences exist, and one
of the bigger questions that remains is how far north the rain
will be able to make it with dry air intruding in from Canada.
From a pattern recognition standpoint, spring setups like this
often seem to keep precipitation further south with dry air
reinforced by cool/dry onshore flow from Lake Superior. Thus,
southerly model solutions are favored. Unfortunately, this means
that a prolonged period of dry and breezy east to northeasterly
winds are expected roughly along and north of US-2 in northeast
Minnesota where wildfires are still ongoing. Near-critical fire
weather conditions will be possible due to the dry and breezy
weather, though temperatures will remain on the cool side with
broad onshore flow from Lake Superior.

The bulk of the rain associated with the low is expected to stay
to our south, but a few hundredths to tenths of an inch of rain
are possible towards Hinckley/Hayward/Prentice. A few rumbles of
thunder can't be ruled out, though the bulk of that should
remain to our south.

Temperatures gradually warm up towards the end of the week as
more broad ridging develops. Some intermittent shower/storms are
possible.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 643 PM CDT Sat May 17 2025

Widespread MVFR ceilings with some scattered to isolated light
rain/sprinkles persist through the evening due to lingering
low-level moisture on the back side of low pressure to the east
of the region. Don't expect visibility reductions from the
precipitation. Some of this rain (20-40% chance) may linger in
the Minnesota Arrowhead down to DLH into Sunday morning. The
signal for MVFR fog at INL/HIB/DLH remains less than 40%
tonight, so opted for some 6SM to cover the patchy fog
potential, though winds may stay elevated enough to stave off
fog production entirely. Can't rule out some VFR ceilings
tonight at BRD if skies scatter out enough, but for the moment
they look to only become broken MVFR ceilings, then improve
back to VFR on Sunday afternoon. Expect all other terminals to
see ceilings dip to IFR tonight into portions of Sunday morning
before returning to MVFR later tomorrow morning and afternoon.
DLH and HIB also have a 20-30% chance to see LIFR ceilings
develop tonight in the 08-14Z timeframe. Winds turn lighter out
of the north tonight and then veer northeasterly for much of
Sunday.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 646 PM CDT Sat May 17 2025

North-northwesterly winds along the North Shore have seen gusts
weaken to below 20 knots, so Small Craft Advisories are no
longer in effect. Winds become northeasterly going into Sunday
and will gradually increase in speed going into Monday and
Tuesday as an area of low pressure passes by to the south.
Expect gusty winds to develop Monday for all nearshore waters
and there is a 40-60% chance of gales on Tuesday.

For the open water discussion, refer to the NWS Marquette Area
Forecast Discussion at weather.gov/mqt.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Frost Advisory from 1 AM to 9 AM CDT Sunday for MNZ010-011-018-
     019-025-026-033>036.
     Freeze Warning until 9 AM CDT Sunday for MNZ012-021.
WI...None.
MARINE...None.

&&

$$

DISCUSSION...JDS
AVIATION...Rothstein
MARINE...Rothstein