236
FXUS63 KDLH 140847
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
347 AM CDT Fri Jun 14 2024

.KEY MESSAGES...

- Sunny and mild weather today.

- Rain and thunderstorm chances return Saturday and linger into
  next week.

- There`s a chance (~5%) for strong to severe thunderstorms on
  Sunday and potential for heavy rain at times Sunday through
  Tuesday that could lead to some flooding issues.

&&

.DISCUSSION...
Issued at 244 AM CDT Fri Jun 14 2024

Today
_______________________________________________________________
Skies are mostly clear out there this morning except for an
area of clouds in northwest Wisconsin, which will move southeast
through the morning. There is some patchy fog out there, which
will diminish shortly after sunrise. With high pressure in
place, we`re looking at a sunny day with mild high temperatures
in the 70s. Some afternoon cumulus clouds will probably develop,
but it should be too dry for any showers today. Today will be a
good day for everyone to take a few deep breaths as we enjoy
some sunshine and a brief break from all the showers and
thunderstorms!

Tonight
_______________________________________________________________
Tonight, expect increasing clouds from southwest to northeast as
we get southerly flow and an upper-level wave promoting some
showers and storms. With this initial round of rain out ahead of
a warm front well to the southwest, there won`t be much
instability to work with, so this is more likely to be a
synoptically-driven rain (~80% chance) with perhaps some
embedded thunder here-and-there, but certainly no storms strong
to severe. PWATs will be increasing to around 1.25", and this
borders around 90th percentile of climatology. With this
potentially being a somewhat long duration (~12 hour) rainfall
for many areas, there`s a ~5-15% chance for excessive rainfall
(per WPC) that could lead to some flooding issues (most likely minor)
Saturday afternoon and night, mainly in northwest Wisconsin.

Sunday
_______________________________________________________________
The trough aloft and attendant rainfall will continue east
Sunday morning. There are timing differences in the models on
how quickly this rain could move out, and this will have
potential implications on how storm chances end up for Sunday
afternoon. Right now, there are a few ingredients in favor of
and in opposition of the potential for some strong to severe
storms popping up Sunday afternoon. Let`s talk about the less-
favorable ingredients first. The upper level pattern does not
appear to be very supportive for convection overall with
potentially weak ridging aloft and an upper level jet to the
west, putting the Northland in the less-favorable right exit
region (i.e. sinking air). Model soundings also suggest
potential for a pretty strong capping inversion aloft with an
elevated mixed layer, and if the timing of the morning rain`s
exit is later, it`ll be more difficult to bust the cap in the
afternoon. With all that said, the warm air advection regime
won`t be going away, and in fact we will have some steep mid to
upper level lapse rates and potentially 2k+ J/kg of MUCAPE to
work with. 0-6 km shear may be offset with higher values to the
west, but perhaps 30-40 kt of shear in the highest instability,
which would be enough to promote strong to severe storms if they
can bust that aforementioned cap. With all that said, there`s a
lot of uncertainty for Sunday, and something we`ll have to keep
an eye on. There`s certainly a marginal chance for some severe
weather (right now ~5% per SPC`s Day 3 outlook), mainly in
northwest Wisconsin.

Sunday night into Tuesday
_______________________________________________________________
There may be somewhat of a break in precipitation Sunday night,
but things get more interesting Monday into Tuesday as a large
upper-level trough deepens over the western CONUS and a warm
front sets up over the northern Plains. Strong warm air and
moisture advection will set up in this period, and the pattern
is looking increasingly favorable for a warm front to become
nearly stationary Monday into Monday night. Severe weather
potential for Monday seems to have dropped off some with higher
stability and moisture near the surface ahead of the warm front.
Nevertheless, there should be at least some instability for
storms, though severe threat is marginal at best. Instead, the
heavy rain threat for this period seems the most concerning.
Models are all over the place for where this warm front and
attendant rain could settle, ranging roughly from southern MN to
eastern ND. Those details will have to be worked out in the
next few days, but for now, there`s increasing concern that PWAT
values rising up into the 1.5"-1.75" range for a good portion
of the region (between 90th and 99th percentile of climatology)
could combine with a potentially stalled front to bring some
locally heavy rainfall and perhaps some flooding or flash
flooding. Again, there`s a lot of disagreement among models yet,
but enough to at least bring up the discussion for the
potential for heavy rainfall.

Tuesday through Friday
_______________________________________________________________
The warm front is expected to eventually lift north through
Tuesday with low pressure developing somewhere in the northern
Plains. Storm chances will likely continue into Tuesday, and
potentially a cold front moving through going into Wednesday to
clear most rainfall out of the region briefly. Models become
increasingly divergent from Wednesday onward, but the upper-
level pattern looks to remain somewhat amplified, so
rain/thunder chances will probably continue through the late-
week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1235 AM CDT Fri Jun 14 2024

The main challenge through the night is fog potential. We have
mostly clear skies and nearly calm winds, which are ideal for
fog formation. Temperature and dew point depressions are still a
few degrees apart around the region, so fog has been slow to
develop. Models are not in good agreement for any particular
terminal, with most suggesting no fog (which doesn`t seem likely
given current conditions). The best potential may be at HIB/DLH,
and possibly at INL/HYR where some models suggest at least some
fog. Most likely, for terminals that see fog develop over the
next few hours, visibility will likely jump up and down between
VFR/MVFR/IFR over short durations. After sunrise, fog should
quickly diminish, leading to very quiet and sunny weather. There
will be potential again for fog Friday night, but confidence is
too low to include in any TAFs at this time.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 244 AM CDT Fri Jun 14 2024

Light and variable winds become northeast this afternoon from
5-10 kt, gusting perhaps up to 15 kt late in the afternoon.
Winds decrease in speed tonight, then increase again Saturday
from the east to southeast from 5-15 kt, gusting to 20 kt
especially around the head of the lake. Winds remain east to
southeasterly Saturday night with rain and storms moving in
(70-80% chance).

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...JDS
AVIATION...JDS
MARINE...JDS