587
FXUS63 KDLH 091727
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1227 PM CDT Tue Jul 9 2024

.KEY MESSAGES...

- Several more days of afternoon/early evening pop up showers before
drier conditions become more prevalent mid week.

- Steadily warming temperatures through the week and into the
weekend. Above normal low and high temperatures expected leading to
increased heat risk. A Heat Advisory may be needed for portions of
the Northland.

- Some smoke from Canadian wildfires moves across the region through
midweek, a little is expected to make it to the surface.

- High water persists across the Rainy River Basin and a Flood
  Advisory is in effect, now until Friday. See Hydro discussion
  for more details.

&&

.DISCUSSION...
Issued at 324 AM CDT Tue Jul 9 2024

Another calm and quiet early morning across the Northland with
patches of fog becoming steadily more widespread. Expect areas of
widespread thin fog and some patches of dense fog by the time the
sun is coming up, but this should burn off fairly quickly through
the morning hours.

Our upper level troughiness persists over the Upper Mississippi
Valley and northern Great Lakes today and tomorrow, but steadily
becomes weather. This will correlate to routine chances of afternoon
showers, but decreasing in coverage and strength each day. Today,
the best chance for showers should be over north-central Minnesota
and portions of the MN Arrowhead, where the better moisture and low
level lapse rates are expected. Wednesday, the best chances are
across the MN Arrowhead, down the Iron Range, and wrapping around
into the St. Croix and Chippewa river basins. A northeast wind over
Lake Superior Wednesday should deliver a light lake breeze
circulation, keeping most showers away from the coastal areas. Some
thunderstorms could be possible, but no severe weather expected. The
chances of strong storms are also decreased.

With this northwesterly flow, some smoke from Canadian wildfires
(originating from northern British Columbia and Alberta) is making
its way across the Northland. Higher concentrations are currently
modeled to stay aloft and further north, but some lighter
concentrations could make it to the surface, especially with an
assist from afternoon thunderstorms mixing the lower atmosphere.
MPCA and WI DNR currently forecast much of NE MN and NW WI to
increase to high end moderate AQI (still below the "unhealthy for
sensitive groups" category however) through Wednesday, and is being
closely monitored for the potential to higher AQIs.

Into Thursday we should be looking at some upper level ridging
bringing some drier conditions Thursday and most of the day Friday.
Global models have a shortwave moving over the border and northern
Great Lakes Saturday/Sunday but still some uncertainty on timing and
exact placement for this.

WAA will be picking up into the weekend, with some of the warmest
temperatures of the summer so far moving in. Widespread temperatures
in the mid to high 80s are likely and some temperatures nearing 90F+
could be possible. Current HeatRisk shows much of the area in a 2
out of 4 level late Friday through Sunday - this level of heat
affects most individuals sensitive to heat, especially those without
effective cooling and/or adequate hydration. This is further
emphasized by overnight lows warming as well, largely staying in the
60s overnight. On Sunday, portions of the area rise into a 3 - this
level of heat affects anyone without effective cooling and/or
adequate hydration. Current ensemble guidance shows that afternoon
heat indices could rise to near 100F for portions of the region.
These above normal temperatures may continue through mid to late
month, per latest CPC outlooks.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1226 PM CDT Tue Jul 9 2024

Diurnally driven cumulus clouds are starting to show growth this
afternoon on satellite. It is another similar set up as the previous
day with pop up storms scouring the Northland with activity waning
after sunset. No severe weather expected put some brief heavy
downpours with small hail will be possible. Some patchy fog will
also be possible (20-40%).

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 324 AM CDT Tue Jul 9 2024

Largely calm conditions expected to persist. Patchy dense fog is
possible this morning, but should burn off quickly through the
morning hours. Afternoon showers and thunderstorms are largely
expected to stay away from the lake today and tomorrow, but an
isolated one could break through the lake breeze. Southerly winds 5-
10 knots through this afternoon, then winds become 5-10 knots out of
the north to northeast through Thursday. Wednesday afternoon, some
stronger northeast wind gusts up to 15 knots could be possible,
especially in the Twin Ports where some waves up to 2 feet could be
possible. Next best chance for widespread rain and thunderstorms
across Western Lake Superior arrives this weekend.

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

&&

.HYDROLOGY...
Issued at 324 AM CDT Tue Jul 9 2024

A Flood Advisory continues across portions of the Rainy River
Basin, extending as far east as Lac La Croix and as far west as the
Rainy Lake outlet. This advisory has been extended through Friday,
but as levels in waterways further east crest, it may be trimmed in
its areal extent through the week. However, for areas further west
the Advisory may need to be extended in time. Lingering high water
from rains in June continue across the Rainy River Basin. The
Vermilion River continues to fall and the River Flood Warning was
cancelled yesterday. This has allowed the lake level increases on
Crane Lake to slow considerably, with less than an inch of rise in
the last 24 hours. Crane Lake may crest sometime in the next few
days, with minimal additional rises. Lac La Croix levels are
cresting and should begin to slowly recede through this week.

All this high water continues to lead to steady rises on downstream
lakes, notably Namakan/Kabetogama (Nam/Kab) lakes where minor
flooding continues, and on Rainy Lake where levels have just exceed
the rule curve. Past events have shown there is a lag between the
crest at Lac La Croix and the crest on Namakan lake of anywhere from
3 to 10 days (the longer coming from events when rain fell around
peak waters). As water levels upstream crest and begin to come down,
rates of rise on Nam/Kab should begin to slow and eventually crest,
possibly by late this week or this weekend. Rates of rise have
slowed to 1-1.5"/day over the weekend and in the last 24 hours there
was only about a 0.5-1" rise on Kabetogama/Namakan as inflows are
decreasing. Until peak, another 3-8 inches of rise could be possible
(estimate, not an official forecast), with the high end of that
range probably being a worst case scenario. This could bring Nam/Kab
just over 1120 feet with a peak level somewhat similar to the high
water during the summer of 2014. This is still 2 feet or more below
the high water levels of Spring 2022 - we are nowhere close to that
level of flooding and extreme rises to that point are currently not
expected. As is usual for this basin, water will move slowly and
recessions will happen at glacial speeds with some flavor of high
water possibly continuing through the month. However, peak should
happen sooner rather than later, based on latest observations.
Additional rainfall may cause brief rises in tributaries and extend
the period of high water in core lakes. Boaters should expect high
water, potentially hidden underwater hazards (including submerged
docks), and strong currents in constricted areas. Generally light
winds are expected, except for possible brief erratic gusts out of
thunderstorms, so wave heights should remain fairly minimal.

&&

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

&&

$$

DISCUSSION...Levens
AVIATION...Britt
MARINE...Levens
HYDROLOGY...Levens