344
FXUS63 KDLH 180915
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
415 AM CDT Mon Aug 18 2025

.KEY MESSAGES...

- A couple waves of rain and thunderstorms move through the area today,
  with rain chances ending from west to east this afternoon.
  Severe storms are not expected.

- High pressure and drier conditions build into the area for Tuesday
 into Thursday morning with increasing temperatures.

- The next chance for rain and a few storms is Thursday into
  Friday, with cooler weekend temperatures.

&&

.DISCUSSION...
Issued at 403 AM CDT Mon Aug 18 2025

A stationary front remains well to our south this morning,
stretching from across the Mid Mississippi River Valley into the
Ohio River Valley. Broad surface high pressure centered south of
Hudson Bay is allowing for east to southeast winds across the
Northland, and despite dewpoints mostly in the 50s, there is plenty
of low level moisture available for cloudy skies. Messy zonal flow
aloft remains across the Northern Plains into the Great Lakes, with
broad ridging over much of the southern CONUS.

Ripples in upper level flow are kicking off a few areas of showers
and storms this morning, and expect additional development as other
weak shortwaves cross the region. The best chances for more rain
remain across northwest Wisconsin, but cannot rule out a
passing shower anywhere in the Northland. Being post- frontal
and with an easterly fetch across the Lake, the airmass is
rather stable and do not expect severe storms. Rain activity
ends from west to east through the afternoon, as upper level
ridging amplifies up the spine of the Rockies and winds aloft
become northwesterly over the Northland. This will bring a
return to drier conditions through mid week as surface ridging
settles over the area.

Ridging is dampened by a trough moving across southern Canada that
will push a cold front through the Northland Thursday into Friday.
Good moisture transport ahead of the front will push PWs above 1.5
inches. Bulk shear values of 40-50kts and lapse rates of 7degC/km
would support updrafts and the potential for strong to possibly a
few severe thunderstorms Thursday afternoon into the evening. Behind
the front, a taste of Fall, with highs in the 60s and lows in the
40s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1238 AM CDT Mon Aug 18 2025

East to southeast breezy winds continue tonight, with gusts up
to 25kts. Orographically enhanced clouds continue at DLH, with a
mix of MVFR/IFR heights. An approaching trough will bring
showers and thunderstorms to terminals overnight through Monday
morning. Currently a broken band of showers is moving eastward
through INL to HIB to DLH to HYR. Behind the line, it is
possible additional showers and a couple thunderstorms develop
overnight and also move west to east through the area. Given the
scattered nature of expected coverage, have include VCSH/VCTS
with prevailing SHRA at times. With increasing low level
moisture, cigs will fall to IFR for all terminals except HYR,
which will remain within the MVFR category. These low cigs will
persist through Monday. Wind speeds decrease through afternoon
Monday, becoming less than 5kts Monday evening.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 403 AM CDT Mon Aug 18 2025

East to southeast winds remain elevated this morning, resulting
in elevated wave heights and hazardous conditions for small
craft continuing near the Twin Ports through mid morning, and
along the North Shore through the afternoon. Wind gusts of
25-30kts remain possible with wave heights up to 5ft. Winds do
weaken through the day and begin a turn to the northeast this
evening.

A few showers or thunderstorms are possible today, with general
thunderstorm hazards possible. Drier conditions return Tuesday
and Wednesday.


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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...Small Craft Advisory until 5 PM CDT this afternoon for LSZ140-
     141.
     Small Craft Advisory until 10 AM CDT this morning for LSZ142-
     143.
     Small Craft Advisory until 7 AM CDT this morning for LSZ144-
     145.

&&

$$

DISCUSSION...HA
AVIATION...HA
MARINE...HA