888
FXUS63 KDLH 210820
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
320 AM CDT Sat Sep 21 2024

.KEY MESSAGES...

- Scattered to numerous showers and thunderstorms this morning
  over portions of the Northland. The storms are not expected to
  be severe this morning.

- Additional thunderstorms will develop this afternoon into the
  evening as a cold front moves through the region. Strong to
  severe storms will be possible, mainly over portions of
  northwest Wisconsin.

- Cooler temperatures develop Sunday into Monday then they will
  warm a few degrees through the week. A mostly dry period is
  expected Sunday through late week.

&&

.DISCUSSION...
Issued at 319 AM CDT Sat Sep 21 2024

A low level jet, as seen at 850mb, of 35 to 45 knots is
forecast by the RAP from eastern South Dakota into central
Minnesota. Area VWPs support this forecast as seen at KFSD/KMPX.
The warm air advection and convergence with the low level jet
has caused showers and thunderstorms to expand in coverage
early this morning with a larger area from around Walker south
and east toward Siren, WI. This is more widespread than the CAMS
and much of the guidance is struggling this morning. We`ve
increased POPs quite a bit and pushed chances this morning
further north and east and increased values using the low level
jet as guidance. Additional short term adjustments will likely
be needed over the next few hours and we`ll monitor radar
closely.

The bulk of these showers/storms should either lift north and
east or diminish later this morning as the low level jet
continues north and east. A shortwave, as seen on water vapor
imagery, will move from the northwest North
Dakota/Manitoba/Saskatchewan border early this morning into
northwest Minnesota by early afternoon then continue
east/northeast brushing northern parts of Minnesota. A surface
cold front will also push east today through central to northern
Minnesota by early afternoon and through far eastern Minnesota
and far northwest Wisconsin by late afternoon finally clearing
the rest of northwest Wisconsin early to mid evening.
Instability will build this afternoon ahead of the front,
especially from east- central Minnesota into northern Wisconsin
with PWAT values rising to around 1.3". Deep layer shear will be
30-35 knots with mid-level lapse rates from 7-7.5 C/km. These
parameters along with the forcing from mainly the cold front
will be enough to produce some strong to severe thunderstorms
from mid to late afternoon through about 02Z this evening. SPC
has a marginal risk, 1 out of 5, over parts of northwest
Wisconsin. The main risks are hail to 1 inch in diameter and
damaging wind to 60 mph. The showers/storms will end overnight
with cooler temperatures moving in on gusty west to northwest
winds.

A quiet stretch of weather is expected from Sunday through most
of next week. An upper ridge will move onto the West Coast early
in the week progressing east toward the Northland mid-late week.
A weak shortwave is forecast to move through the region Tuesday,
but it should not produce much for precipitation and we kept
the forecast dry. Nearly all 80 ensemble members of the
ECMWF/GFS keep Tuesday dry. Temperatures will be closer to
normal Sunday/Monday then warm a bit through the week. Some
frost will be possible in spots Sunday night.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1246 AM CDT Sat Sep 21 2024

Area radar shows scattered showers/thunderstorms from near the
Brainerd Lakes east southeast into northwest Wisconsin. This
activity was occurring with warm air advection and a low level
jet. The showers/storms should impact or be near all TAF sites
tonight. The low level jet will lead to some low level wind
shear into Saturday morning.

The showers/storms tonight will eventually lift north and east
of the area but more will be possible along and ahead of a cold
front today into this evening. Instability will build,
especially from east-central Minnesota into northwest Wisconsin
this afternoon. A few strong to severe thunderstorms will be
possible this afternoon into early evening over parts of
northwest Wisconsin. Winds will switch behind the front to west
then northwest and become gusty. There are some indications that
some lower ceilings, MVFR, will occur right along or behind the
front for a time. For now, we left these low ceilings out of
the forecast.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 319 AM CDT Sat Sep 21 2024

The wind is expected to become easterly for a time today from 5
to 15 knots ahead of a cold front. Winds will switch to west
then northwest behind the front, increasing in speed to 10 to 20
knots with gusts around 25 knots tonight. Thunderstorms will be
possible today into this evening with the main threats cloud to
surface lightning and gusty and erratic wind. We issued a Small
Craft for all areas from Saturday evening into the Sunday
morning.

The wind will be lighter on Sunday, roughly from 10 to 15 knots.

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 from 10 PM this evening to 7 AM CDT
     Sunday for LSZ121-140>142-147-148-150.
     Small Craft Advisory from 10 PM this evening to 4 AM CDT
     Sunday for LSZ143>146.

&&

$$

DISCUSSION...Melde
AVIATION...Melde
MARINE...Melde