366
FXUS63 KDLH 102328
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
628 PM CDT Mon Jun 10 2024

.KEY MESSAGES...

- Rain showers and thunderstorms will move along a cold front
  late tonight through the day Tuesday. Isolated severe storms
  are possible later in the afternoon in portions of
  northeastern Minnesota.

- Above average temperatures will be present Wednesday ahead of
  another cold front bringing another round of showers and
  storms. Severe weather is expected Wednesday.

- More chances for showers and dry conditions in between will
  follow for the late week through the weekend.

&&

.DISCUSSION...
Issued at 151 PM CDT Mon Jun 10 2024

Our beautiful day will come to an end late tonight as a weak cold
front with a closed low moves east across the Northern Plains
into the Northland. Rain showers and embedded thunderstorms are
expected, but should not be severe for this first round. As the
day continues and the first round of showers move east,
southwest flow and WAA at the surface resumes. Increasing
surface moisture from the southwest flow and/or leftover from
the morning showers and increasing instability could lead to
strong to severe storms in the afternoon in our southern area,
especially along the I-35 corridor and far northwestern
Wisconsin. MUCAPE values 1000-2000 J/kg and marginal values of
shear at 25-30 kts with good upper level forcing are expected by
the afternoon in these areas. However, this is highly
conditional that skies clear and therefore allows instability to
build behind the weak cold front. It will be close timing, as
the first line of showers are not forecasted to move passed the
area until early afternoon, and clearing 1-2 hours after the
rain ends. Storms will come to an end late Tuesday evening.

Southwest flow bringing WAA and gulf moisture transport will
start up again Wednesday morning ahead of our second system for
the week. Most of the day will feel a bit sticky, as dewpoints
will reach the upper 50s and lower 60s by the afternoon. A few
models hint at isolated showers in the morning due to the WAA,
but should not affect activity expected in the afternoon. Like
Tuesday, a weak cold front will initiate showers and
thunderstorms in the afternoon. MUCAPE values in the 1500-3000
J/kg range, lapse rates at 7-8 C/km, and strong shear upwards of
50 kts present across the Northland. Storm motion is
expected to be mostly perpendicular to the front, which will
lead to discrete supercells at the beginning of the event. The
combination of high instability and strong, unidirectional shear
above a couple kilometers are indications of large hail (2+
inches), which will be the main threat for Wednesday afternoon.
Large hail is most likely in the southern half of the area. Despite
hodographs showing good turning at the low levels and SRH > 100
m2/s2, LCLs are a bit high for tornados. However, a tornado or
two is not out of the question. As the sun goes down and we lose
daytime heating and surface instability, storms will transition
to a linear mode and the threat will shift to more of a wind
threat.

Thursday, a small shortwave and a stationary front will lead to
additional chances for showers and thunderstorms, especially in
the afternoon. Currently, shear at 40-50 kts and steep lapse
rates support severe weather, but the instability will be
lacking at <1000 J/kg.

For Friday, an upper level ridge will build in the west half of
the CONUS and only grow taller and move eastward as the day
goes on. Winds across the Northland will be mostly from the N
and NW at about 5-10 mph. While an ridge running impulse is
possible, no severe weather is expected as CAPE is practically
zero with deep moisture yet to return.

On Saturday, the ridge bulges more and continues on its
eastward trajectory. Rain and thunderstorms are possible across
the Northland starting in the afternoon due to transport of
moisture from the Gulf, bringing up 50 F dewpoints by Saturday
night. Thunderstorms are expected with the higher dewpoints and
buoyancy with forcing supplied by a wave embedded in the ridge.
Winds aloft are not fast enough to support severe weather as
the shear will not be conducive enough.

Finally, for Sunday the ridge will have moved eastward.
Temperatures into the higher 70s can be expected, some reaching
80 F with favorable mixing. There is a possibility for a strong
mid level jet south of low pressure across Canada, coupled with
Gulf moisture transported northward. Since this is so far out,
severe likelihoods are still uncertain. The timing between the
GFS and Euro models are different, but they both seem to bring a
strong mid level jet with a wave after the departing ridge
along with increasing Gulf of Mexico Moisture. CSU Machine
Learning probabilities also highlight a non-zero severe threat
late this weekend into next week with southwest flow aloft.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 613 PM CDT Mon Jun 10 2024

VFR until a crossing system brings IFR or LIFR ceilings and vsby
reductions in -ra, but also some ts possible early Tuesday
morning. High confidence in IFR or lower ceilings, but not so
much in IFR visibilities. Winds veer from the southeast to the
west through the period.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 151 PM CDT Mon Jun 10 2024

Light and variable winds today will shift to the south along the
South Shore and east along the North Shore for Tuesday. Showers
and storms are possible Tuesday afternoon, though no strong to
severe storms are expected. Ahead of another system, Wednesday
will be warm and winds will shift to the southwest and
increase, with gusts up to 20 kts. Hazardous small craft
conditions are not currently expected, but will need to be
monitored. Another round of storms Wednesday evening and
overnight may be strong to severe over western Lake Superior.

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...KML
AVIATION...Wolfe
MARINE...KML