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000
FXUS63 KDLH 141126
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
626 AM CDT Sun Apr 14 2024

.KEY MESSAGES...

- Near critical fire weather conditions today for much of the Northland
  due to dry relative humidity and breezy northwest winds.
  Monday will also likely see near critical fire weather
  conditions due to widespread dry relative humidity.

- A slow-moving low pressure system is expected to bring rain,
  and eventually rain and light snow, chances to the Northland
  for much of this upcoming workweek.

- Total precipitation amounts and potential snowfall has been showing
  a decreasing trend in recent model runs. This trend is
  increasing confidence that impacts from this week`s slow-
  moving system will be mainly confined to strong winds on
  Tuesday and Wednesday (as well as providing some much needed
  rainfall).

&&

.DISCUSSION...
Issued at 447 AM CDT Sun Apr 14 2024

Conditions have been quiet this morning following a weak cold front
that propagated through overnight. A stalling warm front north of
the CWA in northern Ontario and Manitoba has brought light showers
to the Borderlands early this morning. Expect these showers to
dissipate over the next couple hours as dry air advection occurs.

Near critical fire weather conditions are expected today across a
large portion of the Northland. An appreciable amount of dry air
aloft originating from around 550mb will be advecting into the CWA
this morning. Hi-res model soundings are in solid agreement that
this dry layer aloft will begin to descend towards the surface.
Diurnal sfc heating from abundant sunshine across much of the CWA
today will develop a deep mixing layer in excess of 6,000ft. This
deep mixing layer is likely (70% chance) to drop min RH to 25% or
less across a large portion of the area. When combined with breezy
northwest winds gusting to 20-25 mph, this could lead to the rapid
spread of fires. A Special Weather Statement was issued for these
fire weather concerns today in most locations. This SPS excludes
parts of the Arrowhead where diurnal cumulus will likely be more
prevalent and in portions of northwest WI per coordination with
the DNR.

A similarly dry day is expected tomorrow with minimum relative
humidity of 25% or less as low-level dry air lingers for a large
portion of the CWA. Winds will not be as strong tomorrow as high
pressure briefly builds near and over the upper Midwest. This high
pressure will move downstream by Monday night as a large vertically-
stacked low pressure begins to move into the central CONUS.

This slow-moving low pressure system is expected to bring precip to
the area starting on Monday afternoon/evening and persisting on and
off into Friday. While light rain will likely begin around the
Brainerd Lakes region on Monday afternoon/evening, the heaviest
rainfall associated with this system will be from Tuesday
afternoon through Wednesday morning. In previous forecast
updates, minor flooding was a concern in areas of locally heavy
rainfall. However, recent model trends showing an overall
decrease in total QPF has lessened these concerns. In addition,
MUCAPE availability during the period of highest QPF on Tue PM
to Wed AM will be marginal at best with only 50-100 J/kg. While
thunderstorms are still possible with this limited instability,
heavier rainfall rates will be more challenging to achieve.

While the heavy precip potential is trending down, confidence in
breezy to strong easterly winds on Tuesday into Wednesday is
increasing. Probabilistic guidance from the NBM and LREF shows
a strong potential (80+% chance) for winds in excess of 35-40
mph on Tuesday into Wednesday morning. Most of the impacts from
these strong winds will be occurring over Lake Superior.
However, Wind Advisories may be needed along the North Shore
from Tuesday afternoon into early Wednesday morning if model
trends maintain status quo.

Starting Wednesday night, cooler air will begin to be advected into
the CWA as the vertically-stacked low slowly merges with another low
pressure system over northern Ontario. This CAA is likely to result
in snow mixing in with the rain, if not entirely switching over to
snow in the northern half of the CWA. Impacts from this transition
to snow are currently expected to be minimal due to accumulations
being light from a trace to 3" at most. Similar to total QPF, the
trend has been towards decreased snow amounts in the Arrowhead and
far north-central MN.

The slow-moving low pressure will be propagating downstream on
Friday and Friday night, bringing an end to the on/off precip we are
expected to see this workweek. High pressure returns to the north-
central CONUS on Saturday, ushering in a quiet start to next
weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 626 AM CDT Sun Apr 14 2024

VFR conditions will continue across the region through the 12z TAF
period. Northwest winds will become gusty this morning and remain
breezy until easing this evening. Diurnal cumulus is likely to
develop over the Arrowhead late this afternoon, but cig heights will
remain VFR.

&&

.MARINE...
Issued at 447 AM CDT Sun Apr 14 2024

Southwesterly winds are expected this morning, eventually becoming
variable to northwesterly tonight. As low pressure and rain approach
the region starting on Monday, winds will become breezy from the
northeast late Monday into Monday evening and will continue
strengthening into Tuesday. Wind gusts from 20 to 30 knots will
develop Monday night, then gales will become possible going into
Tuesday through Wednesday morning. Waves will also be building in
excess of 4 feet starting Monday night.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.

&&

$$

DISCUSSION...Unruh
AVIATION...Unruh
MARINE...Unruh