041
FXUS63 KDLH 080903
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
403 AM CDT Wed May 8 2024

.KEY MESSAGES...

- Areas of dense fog clear by 8-9 AM this morning.

- Showers and drizzle this morning and afternoon, with isolated
  thunderstorm potential (20%) later this afternoon and evening
  in inland northwest Wisconsin.

- Frost is expected tonight in the interior parts of the
  Arrowhead, with temperatures down to 33 F. Freezing
  temperatures are expected in northwest Wisconsin Thursday
  night, with additional frost in northeast Minnesota.

- The next round of light rain begins Friday morning in north-
  central Minnesota and builds southeastward Friday daytime.

&&

.DISCUSSION...
Issued at 340 AM CDT Wed May 8 2024

Areas of fog, locally dense, are being observed on satellite
imagery early this morning. The most widespread coverage is in
the east-central MN to Iron Range region, and more isolated over
northwest Wisconsin. Surface observations have shown
intermittent dense fog create visibility less than 1/4 mile, but
more widespread reduced visibilities range from 1/2 to 2 miles
so far this morning. Fog will clear from 8-9 AM this morning.

Drizzle very early this morning becomes more showery in nature
as slighlty better forcing drops southward along a mid-level
backdoor front extending from a shortwave centered in northwest
Quebec from 6 AM to Noon today. In the meantime, a weak surge of
mid-level south-southwesterly flow sets up in inland northwest
Wisconsin late this morning into this evening. Model forecast
soundings show a fairly dry 700-500mb profile, but a few hundred
J/kg of elevated CAPE may allow for a couple hour period of an
isolated thunderstorm to develop. These chances last into the
evening hours for mainly Washburn through Price Counties today.
Severe weather is not expected if any thunderstorm does form.

Drier north to northeasterly flow moves southward through
tonight to scour out skies overnight tonight to partly to mostly
clear. A cold-enough air mass, progged at 850 mb temperatures
around -1 C, will help to create frost formation chances (around
80%) for east-central and northeast St Louis County and all of
the interior parts of the Arrowhead after Midnight tonight and
lasting into early Thursday morning. A Frost Advisory was issued
for these expected conditions. Any limiting factor is most
likely to be surface wind speeds (forecast 4-8 mph) in this time
period so low-lying basins in the interior Arrowhead have the
best chances of any for that frost.

Another round of frost formation is expected in northeast
Minnesota again Thursday night into Friday morning, but
widerspread coverage even down into the I-35 corridor of Pine
County and Aitkin County. Calm winds, dewpoints into the
upper-20s F and 850 mb temps around 0 C support the potential of
freezing or a few degrees below freezing for inland
Bayfield/Ashland/Iron Counties and across Sawyer and Price
Counties from late Thursday evening through Friday mid-morning.
A Freeze Watch may be necessary over coming forecasts for this
potential.

The shortwave trough that moves southeastward from the Canadian
Plains Friday morning is progged to have a bit better frontal
forcing with the 08/00Z guidance. The result is increased
confidence on most locations seeing at least some very light
rainfall begining Friday mid-morning first in far north-central
Minnesota and ending last in the Arrowhead and northwest
Wisconsin Friday evening. The one region which has the best
possibility of missing out on more than a trace would be Cass
and Crow Wing Counties in the Brainerd Lakes region.

Another shortwave trough is progged to move through the region
Sunday to keep chances of rain in the forecast, with
temperatures warming into the low to mid-70s for early next week
as zonal flow to a low-amplitude mid-level ridge sets up.


&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1225 AM CDT Wed May 8 2024

Isolated light rain showers linger along the North Shore and in
northwest Wisconsin over the next few hours, but are not
expected to impact TAF sites. IFR, locally LIFR, visibility and
ceilings are expected to form over the next two hours along the
South Shore, in Aitkin/northern Pine/Carlton Counties and near
the Twin Ports as fog of Lake Superior sets up through 12-14Z
Wednesday morning. Drizzle and isolated vicinity showers are
again expected after the fog lifts later Wednesday morning and
lasting into the afternoon mainly along and south of US Hwy 2.
Easterly winds near the lake increase again gusting to 25 knots
by 17Z Wednesday. Prevailing VFR conditions across the entire
region by 21Z and lasting into Wed night.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 255 AM CDT Wed May 8 2024

Another round of gusty northeast winds is expected first along
the far northern parts of the North Shore early to late this
morning before winds increase in the southwest arm and along the
South Shore towards mid-day today. Small Craft Advisories have
been issued for these increased northeast winds. Wave heights
will again build as well along the South Shore and at the Head
of the Lake by this afternoon and linger into the evening. As
winds decrease from north to south this afternoon and evening,
future changes to the ending time of the headlines may be
necessary. A similar setup to today is expected Thursday where
lighter winds overnight quickly give way to increasing northeast
winds and building wave heights. Another round Advisories may
also be needed Thursday daytime.

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 MNZ011-012-
     019.
WI...None.
MARINE...Small Craft Advisory until 4 PM CDT this afternoon for LSZ140-
     141.
     Small Craft Advisory from 10 AM this morning to 10 PM CDT this
     evening for LSZ142>148-150.

&&

$$

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