282
FXUS63 KDLH 011746
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1246 PM CDT Mon Jul 1 2024

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms this morning
  over mainly central to northern Minnesota.

- A better chance for showers and thunderstorms late afternoon
  into tonight with a risk for heavy rain possibly leading to
  areal/flash flooding. An isolated severe thunderstorm is also
  possible this evening into the early morning hours.

- Another low pressure system will bring more rain, possibly
  heavy, later Thursday into Friday.

&&

.DISCUSSION...
Issued at 350 AM CDT Mon Jul 1 2024

A few showers with an occasional thunderstorm were moving east
into our western area early this morning. This is in response to
warm air and moisture advection. This activity has been handled
poorly by most of the models and even the HRRR has struggled to
catch on. We do push POPs further east into northeast Minnesota
and far northwest Wisconsin this morning but we think coverage
will wane as it pushes further east closer to the high and with
time. We have 20-40% POPS through the morning then diminish them
for a time.

An upper trough will replace the upper ridging that is over the
Northland. 500MB height falls of 50-100M are forecast this
afternoon into tonight. Increasing southerly flow will draw more
moisture north and PWAT values will rise to around 1.75 inches
by this evening which is in the 97-99th percentile. A low level
jet will also strengthen to 40-50 knots this evening. Marginal
instability is forecast today/tonight, partially due to expected
cloud cover and some capping. Little MLCAPE is forecast and
MUCAPE as high as 500-1000j/kg is forecast by the RAP. Effective
shear is marginal. The ECMWF is much lower with forecast MUCAPE.
There may be an isolated severe storm this evening into the
early morning hours. The main severe threat will be hail to an
inch in diameter and perhaps damaging wind to 60 mph.

A bigger threat will be heavy rain. Deep layer winds, 2-7km,
are south-southwest which will support training showers/storms
which could lead to localized heavy rainfall. We`re forecasting
a half to 1.5 inches of rain through Tuesday evening, highest
over north-central Minnesota and the North Shore and most
falling late afternoon/tonight. There is potential for even
higher values as seen in the HREF with pockets of 2"+. We will
continue the Flood Watch for northern Minnesota but did delay
the start by a few hours. Showers and thunderstorms are expected
to ramp up in coverage late afternoon into the overnight hours
then are expected to diminish from west to east later tonight
into Tuesday morning as the low level jet shifts east.

More showers and thunderstorms are forecast for Tuesday. A
surface front will still be west of the Northland in the
morning and will move through Tuesday into Tuesday night. A
strong thunderstorm will be possible Tuesday afternoon into the
evening with MLCAPE ~500 j/kg and supportive shear. Shower and
thunderstorm coverage is expected to be lower than what occurs
tonight.

Most will be dry on Wednesday but we do carry chances for more
showers/storms Wednesday in northern Minnesota which is closer
to an upper shortwave.

Yet another shortwave and surface low arrive Thursday and
departs Friday evening. Another round of showers/storms are
expected and there will a risk of heavy rain, especially from
central Minnesota into the Twin Ports and over northwest
Wisconsin.

Northwest flow aloft will send periodic shortwaves southeast
through the region with more rain/storm chances this weekend
into early next week. These later chances should be more
progressive and feature lower PWAT values reducing the heavy
rain threat.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1242 PM CDT Mon Jul 1 2024

VFR conditions will prevail into tonight before widespread
showers and thunderstorms are expected to move into the region.
A few showers and perhaps a thunderstorm will be possible at INL
over the next few hours, but any impacts are expected to be
brief and minimal. Timing for tonight`s rainfall has been pushed
later with activity not expected to start until midnight or
later. The threat for any strong storms has diminished and are
no longer expected. Ceilings will lower to IFR tonight and
remain there through the remainder of the period. Visibilities
will drop to MVFR overnight with fog looking to linger through
the remainder of the morning hours once rainfall ends. A low
level jet will move across part of the region tonight as well.
The core of the jet has shifted east with the latest model runs
and is only expected to impact HIB, DLH and HYR with low level
wind shear during the early morning hours.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 350 AM CDT Mon Jul 1 2024

Most will see winds at or lower than 15 knots today, with the
Twin Ports having the best chance at them being a bit higher.
Winds will increase a bit tonight, especially along the South
Shore. Gusts of 20 to around 25 knots are expected. We issued a
Small Craft Advisory late Monday night into Tuesday afternoon
from Chequamegon Bay to Saxon Harbor. It`s possible additions to
the advisory may be needed as far west as the Twin Ports but
confidence is lower there. There will be thunderstorms tonight
with the main threat small hail and lightning.

The wind will become more southerly for most of the nearshore
waters on Tuesday with then from 10 to 20 knots with a few
higher gusts. A few more thunderstorms will be possible Tuesday
into Tuesday evening.

Stronger west or southwest winds will occur Wednesday with them
from 15 to 20 knots with higher gusts. Small Craft Advisories
may be needed.

For the open water discussion, refer to the NWS Marquette
Area Forecast Discussion at weather.gov/mqt.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Flood Watch from 5 PM CDT this afternoon through Tuesday
     evening for MNZ010>012-018>021.
WI...None.
MARINE...Small Craft Advisory from 4 AM to 3 PM CDT Tuesday for LSZ121-
     148.

&&

$$

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