344
FXUS63 KDLH 281615
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1115 AM CDT Tue May 28 2024

.UPDATE...
Issued at 1112 AM CDT Tue May 28 2024

Quick update to increase rain shower and thunderstorm
probabilities across the Northland for today with cold
temperatures aloft with the upper level low. Probabilities were
increased the most for the Iron Range and Arrowhead of
Minnesota. Given modest instability and weak shear, severe
weather is not expected.

&&

.KEY MESSAGES...

- Scattered showers and isolated thunderstorms today, with the
  best coverage in the afternoon. Severe weather is not
  expected.

- Dry weather for Wednesday and Thursday.

- Frost Advisory along and north of the Iron Range tonight into
  early Wednesday morning. Additional frost is possible
  Wednesday night into early Thursday morning, with the best
  chances in parts of the Arrowhead and NW WI.

- Rain and thunderstorm chances return Thursday night into
  Friday, with the return of a more active weather pattern
  continuing into early next week.

&&

.DISCUSSION...
Issued at 357 AM CDT Tue May 28 2024

Today:

Light to locally moderate rain showers are ongoing in two
batches early this morning: one batch in NW WI and a more
concentrated band from the Brainerd Lakes up to Hibbing. This
activity is associated with forcing from a shortwave trough
aloft in cyclonic flow behind yesterday`s departing surface low.

Shower activity will shift southeastward into primarily NW WI by
mid-morning. Scattered diurnally driven showers develop later
this morning and persist through early evening. Modest
instability (SBCAPE of 100-300 J/kg in N/NE MN to 300-600 J/kg
for locations south and east of a Brainerd Lakes to Twin Ports
line) will support isolated airmass thunderstorms developing
during this timeframe before diminishing past the early evening.
The best thunderstorm potential/coverage will be where
instability is highest. 0-6km bulk shear will be 20 knots or
less, so thunderstorms are not expected to be strong or severe.
Rain accumulations will generally be less than 0.2" through this
evening, though a few locally higher amounts up to 0.5" aren`t
out of the question for spots that see thunderstorms move
overhead.

Light northwest winds early this morning gradually shift to
northerly today, with gusts up to 15 to 20 mph during the
late morning and afternoon. High temperatures will be slightly
below normal in the low to mid 60s, albeit slightly cooler near
the Lake.

Tonight:

As ridging begins to approach the Northland from the west
tonight, surface high pressure sliding into the region will
bring clearing skies and light winds with it. This will result
in a favorable radiational cooling setup, with low temperatures
tonight into early Wednesday morning dipping into the mid-30s to
around 40 degrees in the Northland. The coldest locations are
expected to be along and north of the Iron Range where at least
patchy frost is looking increasingly likely. Therefore, we have
issued a Frost Advisory for those locations. Parts of inland NW
WI may also dip into the mid-30s, but expected coverage is too
limited with the current forecast to issue a Frost Advisory in
NW WI.

Wednesday - Thursday:

High pressure moves into the Northland under shortwave ridging
aloft on Wednesday and gradually slides to our east on
Thursday. This will lead to a period of dry weather and mostly
clear skies with high temperatures in the mid-60s to low-70s on
Wednesday and low- to mid-70s on Thursday. Increasing winds out
of the south will begin across north-central MN Wednesday night
and then spread across most of the Northland on Thursday with
gusts over 20 mph on daytime Thursday. Some patchy frost will be
possible again Wednesday night/Thursday morning in the
Arrowhead and portions of NW WI where lighter winds could lead
to another round of radiational cooling and low temperatures
dipping into the mid-30s.

Thursday night - Early Next Week:

Upper-level troughing cutting eastwards across the Canadian
Prairies and Montana/North Dakota on Thursday will push a few
embedded pulses of shortwave energy through the Northern Plains
and Northland. The first of these shortwaves and attendant
surface cold front will slide east across the Northland starting
Thursday night and continuing into Friday, with a 60-80% chance
of showers and thunderstorms associated with it. The second
round of precipitation chances (40-60%) are most likely to
arrive on Saturday with the second shortwave with decent
ensemble agreement with regards to precipitation timing. There
doesn`t look to be any good signal for heavy rain or severe
weather for Thursday night into early next weekend.

This more active weather pattern persists the remainder of the
weekend into early next week as additional shortwaves are
forecast to move through a more zonal flow pattern. Ensemble
spread increases late weekend into next week, so confidence in
timing and amounts of additional precipitation is lower at the
moment.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 647 AM CDT Tue May 28 2024

Ongoing light showers from KY49 to KEVM and areas south and
east. Conditions have been mainly VFR with these showers, but
there have been a few isolated pockets with MVFR visibilities.
The morning showers continue to push southeast through NW WI
into mid/late morning. Scattered diurnal showers develop again
over much of NE MN and NW WI around midday and persist into
early evening before diminishing. There is enough atmospheric
instability for a few isolated thunderstorms this afternoon.
Coverage is too limited to include as a prevailing weather
group, but did include VCTS at KDLH and KHYR for this afternoon.
May need some updates to the TAF if coverage/confidence trends
higher. Some MVFR ceilings are expected for KINL from mid
morning into early afternoon. MVFR conditions are also possible
if a more moderate shower or any thunderstorms move directly
over a terminal today.

Light northwest winds turn northerly this afternoon with gusts
of 15 to 20 knots, strongest at KBRD and KHIB. Winds turn light
to calm this evening and tonight.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 357 AM CDT Tue May 28 2024

Winds will be 15 knots or less through Wednesday night.
Northwest winds today veer northerly late this afternoon and
evening and northeasterly tonight. There may be some isolated
thunderstorms this afternoon into early evening over the far
western part of the lake. Northeast to easterly winds persist
into Wednesday. While winds are not currently forecast to get
above 15 knots for western Lake Superior, one exception on
Wednesday could be the Twin Ports due to funneling of winds
down the southwest arm of the Lake.

Easterly winds will continue into Thursday and be a bit
stronger yet as the pressure gradient increases with a departing
high pressure to our east. Generally expect 10 to 20 knots with
a few higher gusts, with the strongest winds in the Twin Ports.

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 7 AM CDT Wednesday for MNZ010>012-
     018-019-021-026.
WI...None.
MARINE...None.

&&

$$

UPDATE...PA
DISCUSSION...Rothstein
AVIATION...Rothstein
MARINE...Rothstein