788
FXUS63 KDLH 061744
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1244 PM CDT Mon May 6 2024

.KEY MESSAGES...

- Quiet and breezy weather today with some elevated fire weather
  conditions as relative humidity falls to around 25-40%.

- Rain and thunderstorms move in late Monday night through
  Tuesday night. Rainfall amounts around a quarter to one inch
  with locally higher amounts possible. Isolated strong to
  severe storms possible (~10% chance).

- Lingering light rain and possibly some thunder (15% chance)
  Wednesday and Thursday. More rain is possible into next
  weekend.

&&

.DISCUSSION...
Issued at 402 AM CDT Mon May 6 2024

It`s a very quiet morning out there with light and variable
winds and mostly clear skies thanks to ridging aloft. This ridge
will lead to plentiful sunshine today (increasing clouds this
afternoon). Fire weather will be a bit elevated as the pressure
gradient increases this afternoon ahead of approaching low
pressure for Tuesday. East to southeast winds will gust up to
20-30 mph this afternoon and min RH is expected to fall to
anywhere from 25% to 40%. However, areas falling between that
25%-30% are expected to be isolated mainly to areas near the
International Border. With plentiful rain in the past several
days/weeks, the ground is starting to moisten up and green up.
Thus, near-critical fire weather is not expected.

Going into Monday night, a warm front and elevated frontogenesis
is expected to bring an initial round of rain through the region
as it spreads northward. This rain will be supported by PWATs
approaching 1" or so. A little instability is possible Tuesday
morning to support a thunder threat (up to ~500 J/kg; 10-15%
chance). Any morning convection should be elevated and non-
severe. With favorable synoptic forcing and marginally favorable
convective forcing possible, the bulk of the total ~0.25-1.0"
rain totals may fall Tuesday morning.

The thunderstorm threat increases Tuesday afternoon and early
evening as some surface-based heating may be realized for
convection. Models are still somewhat divergent on how much
instability there could be, but the range is from <500 J/kg to
nearly 1,000 J/kg. Low and mid-level lapse rates still look
marginal for severe storms as do shear profiles (we lose most
low-level speed shear by the afternoon). With all that
considered, we have a situation where severe weather looks
largely unlikely, but we have ~40-50% chances for storms (which
could be strong, containing small hail and gusty winds up to 50
mph) and a ~5-10% chance that a storm or two could produce 1"
diameter hail and winds gusting to 60 mph. The best timing for
thunderstorms currently looks to be about 2 PM to 8 PM, with any
severe potential around 4 PM to 8 PM or so. Depending on overall
timing of the low and attendant synoptic clouds/rain, the threat
for storms Tuesday afternoon/evening could still increase or
decrease a bit. Stay tuned to the forecast for updates!

Low pressure will move east on Wednesday into Thursday with
some lingering showers and perhaps isolated thunderstorms as
areas of cyclonic vorticity advect through aloft. Rainfall
amounts at this time look to be up to around a tenth of an inch
or so through this period.

There may be a brief window for dry weather Thursday night
before another rainy system potentially moves in from the
northwest and sticks around through next weekend, bringing
additional rain chances.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1245 PM CDT Mon May 6 2024

The pressure gradient continues to strengthen today, leading to
increasing southeasterly winds and gusts. Look for 18-25 knot
gusts this afternoon and evening, highest at BRD. Even with
these gusty surface winds, LLWS will be a concern late this
evening and tonight as a south-southeasterly low-level jet of
40-50 knots moves over the Northland. Winds turn even stronger
out of the east late tonight into Tuesday, with some gusts up to
30-35 knots at times, particularly in northeast Minnesota.

VFR conditions persist until later tonight when light to
moderate rain moves into BRD around 07-08Z from the southwest
and spreads northeast across the Northland into Tuesday morning
on the leading edge of a warm front. There may even be some
embedded thunder at BRD overnight into Tuesday morning (10-20
percent chance), but confidence was too low to include in the
TAF at this time. Expect MVFR visibility in the rain, while
ceilings quickly drop through MVFR to IFR as the main band of
rain moves over the terminals.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 1233 PM CDT Mon May 6 2024

Winds and waves are expected to strengthen from the northeast
today ahead of an approaching low pressure system from the west.
Gusts from 20 to 25 knots are expected to develop early this
afternoon, especially around the head of the lake. Breezy
conditions will continue through Tuesday before winds lighten up
Tuesday night. Small Craft Advisories are in effect.
Probabilities for gales during the period of strongest winds
around mid-day Tuesday still look to be around 40-50%, so we
will continue to monitor that potential. Rain and a perhaps a
thunderstorm or two are expected Tuesday through Tuesday night.

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...Small Craft Advisory from 7 AM Tuesday to 1 AM CDT Wednesday
     for LSZ140-147-150.
     Small Craft Advisory from 4 AM Tuesday to 1 AM CDT Wednesday
     for LSZ141-142.
     Small Craft Advisory until 1 AM CDT Wednesday for LSZ143>146.
     Small Craft Advisory from 10 AM to 4 PM CDT Tuesday for LSZ148.

&&

$$

DISCUSSION...JDS
AVIATION...Rothstein
MARINE...JDS