699
FXUS63 KDLH 292336
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
636 PM CDT Wed May 29 2024

.KEY MESSAGES...

- Frost is expected tonight in the Arrowhead, North Shore high
  terrain ridge, and across much of northwest Wisconsin and all
  of north-central Wisconsin late tonight into early Thursday.

- Multiple rounds of showers and thunderstorms begin Thursday
  night and last into early next week.

&&

.DISCUSSION...
Issued at 316 PM CDT Wed May 29 2024

Surface high pressure and a high-amplitude mid-level ridge
remain over the Northland this afternoon, creating those mostly
sunny skies and light winds across the Northland. Satellite
imagery shows an advancing lake breezing into east-central and
northeast Minnesota late this afternoon and will continue inland
for the next few hours. Expect the diurnal cumulus to dissipate
around and shortly after sunset.

Prime radiational cooling with lingering dewpoints in the
low-30s could create some frost in the Arrowhead late tonight
lasting into early Thursday morning. The better chances for
those lowest temperatures around 34/35 F late tonight are in
northwest to north-central Wisconsin. Frost remains in the
forecast for tonight and due to this Frost Advisories have been
issued for 1 AM to 9 AM Thursday. The City of Superior had
higher (60%) chance of reaching 34-36 F tonight, whereas the
Duluth side of the Ports only had a 30% chance of approaching
anything lower than 38 F so kept without an Advisory for South
St Louis and Carlton so far.

Deep low pressure over central Canada will have a few shortwave
troughs rotating through from west to east over the next few
days per deterministic global guidance. The first shift flow
southerly Thursday morning over the Northland as it crosses
through the southern Canadian Plains. A line of rain showers
moves into north-central Minnesota associated with that first
shortwave late afternoon to early evening hours tomorrow. A
fairly widespread 1/4 to 1/2 inch of rainfall is expected
Thursday night in northeast Minnesota, with lesser amounts
closer to 1/10 to 1/4 inch in northwest Wisconsin by early
Friday morning.

A lingering frontal boundary promotes continued shower chances
in the Northland for Friday daytime, especially as mid-level
impulses of energy lift northward. There is a bit uncertainty on
just where these Friday daytime rain chances setup best on
either side of the MN/WI stateline so broad PoPs work for now.

The mid-level ridge that is over us today keeps parked over the
eastern US for this weekend, but that central Canadian low
pressure slowly whittles away at the ridge into early next week.
This allows a potentially fairly wet system to setup over the
Upper Midwest Sunday into Monday as a northern US Plains low
phases with the deeper mid-level Canadian low. The deep and
moist southerly advected airmass ahead of the low later Sunday
creates the best heavy rainfall chances for late Sunday night
into early Monday morning. A third shortwave low could then
create continued every 36-48 hr rain chances again into mid-next
week.

Temperatures remain in the 70s until Sunday when fairly
widespread 80s are expected into early next week, which would
be about 10 degrees above normal for most locations.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 636 PM CDT Wed May 29 2024

VFR conditions are expected to prevail through the period.
Clouds will increase Thursday afternoon ahead of an approaching
cold front and become broken to overcast. Any showers or
thunderstorms associated with the front are not expected to push
into the far western reaches of the area until late afternoon or
early evening. Have kept out of BRD with this update, but may
need to be added in if timing is quicker. Winds will be light
and variable this evening before becoming southerly overnight
with gusts to 20 knots by mid morning.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 250 PM CDT Wed May 29 2024

High pressure over the central US keeps quiet and dry weather in
place through Thursday afternoon. Light easterly winds at or
less than 10 knots prevail through Thursday evening, except at
the head of the lake where gusts to 20 knots are possible
Thursday afternoon. Thunderstorm chances build Thursday night
and last into Friday before another rainy pattern begins.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Frost Advisory from 1 AM to 9 AM CDT Thursday for MNZ012-
     019>021.
WI...Frost Advisory from 1 AM to 9 AM CDT Thursday for WIZ001>004-
     008-009.
MARINE...None.

&&

$$

DISCUSSION...NLy
AVIATION...BJH
MARINE...NLy