364
FXUS63 KDLH 171720
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1220 PM CDT Tue Sep 17 2024

.KEY MESSAGES...

- Warm and muggy again today and tomorrow with some isolated storms
  possible

- Severe storms possible Thursday afternoon and evening as a cold
  front moves in from the west.

- More seasonable temperatures look to return Sunday into next
  week.

&&

.DISCUSSION...
Issued at 344 AM CDT Tue Sep 17 2024

Current Conditions/Today:

A stalled out boundary draped along the International Border is
bringing some showers and thunderstorms across the north. Further
south a weakening low level jet has spurred some light rain moving
across north central MN. We will continue to carry some PoPs (20-
30%) through the day. High res guidance has been very little help as
it tends to struggle with weakly forced environments. However,
looking at some of the isentropic charts reveals prominent
moisture pooling and lift through the Brainerd Lakes Region and
towards the Borderlands. Another humid day will be on tap with
dewpoints in the 60s. We will manage to build out some
instability this afternoon (1000 J/kg). Shear remains weak but
a few storms can`t be ruled out.

Tonight/Tomorrow:

Overnight and Wednesday follows a similar pattern. An upper level
trough over the Great Basin propagates towards the Northern Rockies.
Meanwhile, out east a semi Rex Block weakens. Leaving us with
another strong low level jet moving moisture into the region and
allowing weak forcing for ascent. Additional chances (20-30%)
for showers and storms will populate across the MN side of the
CWA.

Thursday/Severe Threat:

On Thursday a cold front associated with a vertically stacked low
treks east across the region. Timing of the arrival and departure is
still a bit in flux. The latest update has the arrival slightly
sooner then the previous package. This would have the front
moving through MN in the afternoon and NW WI in the evening
hours. A small corridor of favorable severe parameters sets up
across our region with this FROPA. Moderate instability with
MLCAPES in excess of 1500 J/kg will combine with bulk shear
values greater than 40 kts to promote upscale storm growth.
Cells may initially be discrete before congealing into a line
through their life cycle. Mid level lapse rates of 8C/km will
aide in hail growth. There is also some indication of low level
curvature in the hodographs allowing for a small window of
tornadoes. Currently SPC has our severe weather outlook as a
slight (2 out of 5).

Friday into early next week/Cooling trend:

The system will exit through Friday with temperatures cooling
slightly into the mid 70s. We will see another cold front work in
from the west on the weekend bringing more rain chances and
some isolated storms. Behind this front temps quickly fall back
to seasonal norms on Sunday and maintain themselves into early
next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1220 PM CDT Tue Sep 17 2024

Predominantly VFR conditions continue through the TAF period.
INL may see some isolated showers and thunderstorms late this
afternoon or early this evening, but latest trends have pushed
the best chance of precipitation north of the border. Overnight,
expect an area of showers and thunderstorms to build along a
low level jet which may impact INL and BRD, with a slight chance
that showers reach HIB. The low level jet may lead to some LLWS
at DLH overnight.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 344 AM CDT Tue Sep 17 2024

Light southeast winds across the Lake with speeds of 5 to 10 kts. A
few isolated thunderstorms will be possible in the afternoon.
Overall, winds continue to remain light through with some
intermittent thunderstorms. On Thursday there will be a chance for
severe storms in the afternoon and evening. Winds and waves
currently don`t look to increase until later this weekend.

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...None.

&&

$$

DISCUSSION...Britt
AVIATION...Levens
MARINE...Britt