174
FXUS63 KDLH 092058
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
358 PM CDT Fri May 9 2025

.KEY MESSAGES...

- Near-critical fire weather conditions through early this
  evening across parts of northeastern Minnesota away from Lake
  Superior.

- Sprinkles and chances (10-20%) for a few showers and perhaps a
  rumble of thunder, mainly across northwestern Wisconsin
  through early this evening.

- Unseasonable warm and dry conditions persist through the
  weekend and into early next week. A Fire Weather Watch remains
  in effect for Sunday with additional fire weather headlines
  possible Monday and Tuesday.

- Relief from hot temperatures and the drier conditions arrives
  later next week as precipitation chances return and
  temperatures cool closer to normal.

&&

.DISCUSSION...
Issued at 357 PM CDT Fri May 9 2025

Rest of Today - Tonight:

A surface cold front located in east-central MN to the Twin
Ports and up the North Shore as of 3PM CDT continues sweeping
southeast across NW WI through the remainder of the afternoon
into early evening. While there have been occasional reports of
sprinkles/isolated brief rain showers as the front moves
through, most precipitation has been evaporating before
reaching the ground. Can`t rule out a rumble of thunder or two
in NW WI late this afternoon and early evening given some weak
instability that develops, but chances are less than 20%.

Very dry air in the lower levels of the atmosphere has led to
relative humidities in the 20s ahead of the front in NW WI and
subsidence/mixing of RH into the low to mid-20s (%) behind the
front. Areas of the front see brief improvement in RH to the
upper 20s to low 30s. Combined with increasingly breezy
northwest winds in the wake of the front, near-critical fire
weather conditions are expected to persist for the remainder of
the afternoon into early evening for most of NE MN where a
Special Weather Statement is in effect with the exception of the
North Shore. There has also been some haze from Canadian
wildfire smoke mixing down to the surface for a few hours
behind the front, but there hasn`t been much visibility
reduction with it. Relative humidities should improve this
evening as temperatures cool around and after sunset.

Saturday - Saturday Night:

Surface high pressure moving across Ontario tonight and Saturday
and then to the east Saturday night will lead to another round
of easterly winds off of Lake Superior and a lake breeze to push
inland. Locations near Lake Superior should see highs in the
50s, with 60s to low/mid 70s farther inland where more
southeasterly to southerly flow develops during the latter half
of the day. The airmass will still be dry on Saturday, though
perhaps a few percentage points higher for minimum relative
humidity. Still should see some areas drop into the 20-25%
relative humidity range, mainly for areas inland from the lake
breeze in north- central/NE MN and inland NW WI creating
additional near- critical fire weather conditions. Winds gusts
should generally remain under 20 mph most of the day, though
should start to pick up with return flow in north-central MN
later Saturday afternoon into Saturday night.

Sunday - Tuesday:

Upper-level ridging builds into the region for Sunday, but some
weak upper-level vorticity along the edge of the ridge may lead
(10-20% chance) to a few showers along the International Border
Saturday night into early Sunday along a warm front, though
most of this activity looks to remain north of the International
Border. Little to no accumulation expected from the rain.

The pattern shifts to hot and dry for Sunday into at least
Tuesday and possibly Wednesday of next week as the upper-level
ridge lingers over the region. Strong warm air advection from
gusty south-southwesterly to southerly winds each day will cause
high temperatures to soar well above average to near record
territory in the 80s. Some locations in north-central MN could
even touch 90 degrees Sunday-Tuesday. Nightly lows will also
remain warm in the 50s to low 60s. See the "Climate Section" of
the discussion below for more details on record temperatures
that could be approached or broken Sunday into early next week
for both high and low temperatures. Areas in the immediate
vicinity of Lake Superior should stay less hot, primarily along
the North Shore due to southerly winds.

Of big concern for Sunday into early next week will be a drier
airmass remaining in place along with the gusty southerly winds
and hot temperatures. Portions of the area--particularly in the
MN portion of the Northland--will likely see relative
humidities drop to 20-25%, though some of these lower relative
humidities could bleed over into portions of NW WI as well,
especially on Sunday and Monday. Combined with the gusty winds,
near-critical to critical fire weather conditions are possible
and Red Flag conditions could even occur Sunday and Monday, and
to a lesser extent on Tuesday. A Fire Weather Watch is in
effect for most of north-central and northeastern MN for
Sunday, and additional fire weather headlines may also be
needed on Monday and Tuesday.

Mid - Late Next Week:

Global ensemble guidance continues their fairly good agreement
of the ridging aloft breaking down for the Upper Midwest later
Wednesday through late this week as, with an upper-level trough
across the western CONUS pushes northeast across the Northern
Plains and Upper-Midwest. The pattern shift with this system
would favor temperatures returning closer to normal values and
increasing precipitation potential. Precipitation/thunderstorm
chances with this system will depend on the amount of
instability and moisture return, but machine-learning based
severe model guidance still shows some of a signal for severe
weather potential late week if favorable atmospheric conditions
line up.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1221 PM CDT Fri May 9 2025

A weak cold front is moving southeast through the region this
afternoon and evening, bringing scattered to broken VFR clouds
as well as a few showers, though most precipitation is falling
as virga and not reaching the ground. Shower potential does get
a little better (20 percent chance) mid-afternoon into early
evening in northwest Wisconsin, and a few rumbles of thunder
there cannot be ruled out, but the potential is very low (less
than 20 percent chance). There is also some Canadian wildfire
smoke immediately behind the front that could produce MVFR
visibility for a few hours after the front passes through. Winds
will be breezy with gusts to 20-25 knots, particularly behind
the cold front as winds veer to northwesterly this afternoon
into evening before weakening overnight.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 357 PM CDT Fri May 9 2025

Northwest winds this afternoon veer to northerly this
evening/tonight behind a passing cold front, which could produce
a short window of evening gusts along the North Shore up to 25
knots. A short-duration Small Craft Advisory has been issued for
Silver Bay to Grand Portage to cover this threat. High pressure
on Saturday will turn winds easterly to northeasterly with gusts
of 10 to 20 knots, highest in the western arm of the lake.
Breezy southwesterly winds are then forecast for Sunday into
early next week with gusts to around 25 knots which may lead to
hazardous conditions for small craft depending on how far the
winds can extend into the stable layer of Lake Superior.

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

&&

.CLIMATE...
Issued at 357 PM CDT Fri May 9 2025

Record High Temperatures:

May 11:
KDLH: 83/1991
KINL: 83/1993
KBRD: 92/1900
KHIB: 83/1991
KASX: 85/1992

May 12:
KINL: 86/1991
KBRD: 88/1940

May 13:
KINL: 87/1977

Record High Minimum Temperatures:

May 12:
KDLH: 56/1991
KINL: 55/2023
KBRD: 60/1991
KHIB: 53/1944
KASX: 58/1894

May 13:
KDLH: 54/1991
KINL: 55/1987
KHIB: 52/1987
KASX: 58/1987

May 14:
KINL: 58/1977
KBRD: 62/1998
KHIB: 54/1998

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Fire Weather Watch from Sunday morning through Sunday evening
     for MNZ010-011-018-019-025-026-033>038.
WI...None.
MARINE...Small Craft Advisory from 7 PM this evening to 1 AM CDT
     Saturday for LSZ140>142.

&&

$$

DISCUSSION...Rothstein
AVIATION...Rothstein
MARINE...Rothstein
CLIMATE...Rothstein