657
FXUS63 KDLH 120849
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
349 AM CDT Wed Jun 12 2024

.KEY MESSAGES...

- Showers and a few thunderstorms this morning

- Severe storms ignite this afternoon and evening with hail up to 3"
  diameter possible. Damaging winds and a possible tornado can`t be
  ruled out as well. Severe risk level has increased to 3 out of 5

- Quiet weather for Friday before activity increases for the
  weekend.

&&

.DISCUSSION...
Issued at 337 AM CDT Wed Jun 12 2024

Current conditions/This morning:

A jet maxima at 500mb is moving across NW MN this morning with
speeds of 55kts aloft. Within this corridor some showers and storms
have developed within a sector of weak MUCAPE. Another area of
interest is developing over west central MN where storms are
beginning to initiate as the EML interacts with low level
moisture advection. Southeasterly flow will take all this
activity across the region through the morning hours.

This afternoon/evening:

The aforementioned showers and storms will move into NW WI by late
morning allowing for ample time for the environment to recover for
another round of storms this afternoon and evening. Moisture vectors
ramp up significantly out of the SW as a low level jet accelerates
to near 40kts. PW values of 1.3" were observed across KS this
morning and ALPW supports the movement of this moisture up into the
Northland. Warm air advection will overrun the region with highs
climbing into the 80s. Dewpoints will also increase into the lower
60s. Our environment will become very unstable by the afternoon
hours with MLCAPE of 2000-3000 J/kg. Bulk shear is also in excess of
50 kts further supporting the development of supercells.

The only potential "bust" scenario for severe weather looks to be a
line of storms that could develop later this morning along the
ND,SD,MN border. A few CAMs have these storms surging southeast
through the morning which could limit the amount of moisture
available to advect into the Northland. However, initiation of these
storms continues to be delayed in subsequent model runs and with the
strong theta-e advection expected today severe weather still seems
likely.

An EML will move in from the west early this afternoon and likely
act as the catalyst to start firing discrete storms across northern
MN. Mid level lapse rates of 8C/km will promote rapid upscale growth
and the favorable tilt in the storms will lead to longer residency
times for hail stones to grow. Large hail up to 3" in diameter will
be possible. There is a brief window (5-7pm) where low level helicity
and hodographs look favorable for a few tornadoes to develop.
Confidence is still on the low side for tornadoes as the LCL heights
are a little on the high side (2000ft). Additionally, steep low level
lapse rates with DCAPE values over 1000 J/kg indicate a threat for
damaging winds upwards of 70 mph. Overall, SPC has upgraded us
to a level 3 out of 5 for severe weather today.

A cold front moving across the region will help to usher activity
along as we head into the evening hours with most CAMs seeing a
decrease in activity after 11PM.

Thursday/Friday:

Cooler temperatures in the wake of the cold front from the previous
day with highs in the 70s. A broad upper level trough will be
situated over the Northland. With the help of diurnal heating we
could see some scattered showers and storms. Some strong storms will
be possible as we retain some decent bulk shear (40 kts) but
instability will be limited (MLCAPES ~100 J/kg). Anything that does
manage to develop will quickly diminish after sunset. As we move
into Friday high pressure builds in overhead suppressing PoPs and
allowing highs to climb into the upper 70s.

Weekend:

Guidance begins to vary as we head towards the weekend. Cluster
analysis supports a ridge over central CONUS with a subtle wave
embedded across the Plains. We currently have PoPs returning on
Saturday and Sunday. The 00Z suite of guidance is leaning
towards a cold front sweeping in for Sunday that could bring
some strong to severe storms. Still quite a ways out to really
toss out any more details.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1225 AM CDT Wed Jun 12 2024

Mostly clear skies to start the forecast period. There is some fog
development over HYR that should dissipate later this morning.
Satellite does show some rain showers moving into northwest MN that
will eventually spread across the region through this morning. A few
embedded storms will be possible in the later morning hours. After
this first wave of activity a more severe weather day will be on tap
for the afternoon and evening hours. Large hail in excess of 2" will
be possible as well as damaging winds and some isolated tornadoes.
This activity is expected to diminish west to east as a cold front
moves across the region through the evening hours.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 337 AM CDT Wed Jun 12 2024

Southwest winds today with gusts up to 20 kts. There is some patchy
fog primarily along the North Shore this morning that will clear up
a few hours after sunrise. A few showers and storms will be possible
through the morning hours. This afternoon and evening will see
severe storms develop across MN and move east into the Lake.
These storms will be capable of hail up to 3" in diameter and
damaging winds gusts up to 70 mph. This activity will continue
into the evening with storms weakening and exiting western Lake
Superior after 11 PM. Enhanced westerly winds could lead to
hazardous conditions for small vessels on Thursday.

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...Britt
MARINE...Britt