917
FXUS63 KDLH 120905
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
405 AM CDT Mon Aug 12 2024

.KEY MESSAGES...

- Scattered rain showers and isolated thunderstorms are possible
  (15 - 30 percent chance) Monday and Tuesday in the afternoon
  and evening.

- Rain chances increase to 50 - 70 percent later Wednesday and
  last into Friday

- Temperatures in the upper 70s to low 80s through Wednesday
  decrease into the low to mid 70s Thursday onward.

&&

.DISCUSSION...
Issued at 405 AM CDT Mon Aug 12 2024

Water vapor satellite imagery early this morning shows an
upper-level boundary draped over northwest Minnesota into north-
central Wisconsin and extending through southern parts of Lower
Michigan. Surface high pressure immediately under this boundary
is promoting very little winds aloft and clear skies overnight
tonight. A plume of more moist air will remain situated over the
Borderlands, Arrowhead and into the South Shore during the
daytime today. After morning diurnal destabilization, anywhere
from 300-700 J/kg of CAPE build into that more moist airmass
aloft part of the Northland to kick off another round scattered
rain showers and isolated thunderstorms later today. The 10
knots or less of low to mid-level flow will allow for pulse
general thunderstorms that can break a mid- level cap. This very
weak steering flow will also mean that storms stall out over
locations and could bring some moderate rainfall along and
northeast of US Hwy 2 in northeast Minnesota. Very localized
amounts of 0.25-0.5 inches of rainfall are expected for a few
locations from late afternoon to early evening today.

A drier airmass is progged to move over the rest of the
Northland from tonight into Tuesday and further limit the
already widely scattered shower potential on Tuesday.
Temperatures under a seasonal airmass will be in the upper-70s
to low-80s for the first few days of this work week.

The ridge axis that is slowly moving through the Northern
Plains today and Tuesday passes east of the Upper Midwest
Tuesday evening to setup southerly return flow. The more moist
airmass helps to limit overnight surface temperatures from
dropping out later this week compared to the upper-40s and
fifties that are being observed and expected for the first
couple of night this week.

Low pressure centered in the Central Canadian Prairies Wednesday
drapes a warm front over the northern US Plains Wednesday that
moves the Northland beginning Wednesday night. In the meantime,
an area of surface low pressure deepens over the Lower Midwest
Thursday morning and further increases the chances of moderate
rainfall in the Northland by Thursday afternoon. The highest
chances of any very localized heavy rainfall would be northwest
Wisconsin into east-central Minnesota along an occluded front.
Temperatures decrease by late this work week down into the low
to mid-70s F. As the Central Canadian deeper low passes to the
north of the Northland, a trailing cold front helps to decrease
rainfall chance Friday night onward as the low pressure to the
south moves eastward. Wrap around cold core rain showers remain
possible (20-30 percent chance) though into the weekend under
northerly flow aloft.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1230 AM CDT Mon Aug 12 2024

After a night of patchy fog creating periods of LIFR to MVFR
visibilities, Monday will feature another day of light surface winds
under 10 knots. A pool of mid-level moisture under a stronger
cap aloft will help to trigger diurnal scattered rain showers
and isolated thunderstorms in the afternoon and early evening
hours Monday. The better chances are for more terminals outside
of the Brainerd Lakes region. A VCTS may be needed in place of
the current VCSH in future TAF amendments tomorrow for any area
thunderstorms.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 320 AM CDT Mon Aug 12 2024

Southwest winds 5 to 15 knots today and Tuesday are forecast
with afternoon scattered rain showers and isolated
thunderstorms. Winds shift to easterly Wednesday and are
expected to build to 15 to 20 knots at the head of the lake by
later Wednesday and create wave heights around 2 feet.

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