051
FXUS63 KDLH 041139
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
639 AM CDT Thu Jul 4 2024

.KEY MESSAGES...

- Active pattern continues with a chance for moderate rain this
  afternoon through Friday. The greatest chance of 0.5-1.5
  inches is mainly south of a line from the Brainerd Lakes to
  Moose Lake to Ashland, WI.

- Another system will bring additional chances of rain this
  weekend.

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

&&

.DISCUSSION...
Issued at 416 AM CDT Thu Jul 4 2024

A nearly stationary front stretched from central Nebraska to
southwest Minnesota to near Green Bay, WI to eastern Upper
Michigan early this morning. A weak area of low pressure was
positioned near Sioux City, IA. A modest baroclinic leaf
signature was noted on GOES-East IR imagery from western Iowa
into northeast Minnesota. A 90-100 kt jet streak was located
upstream over Idaho and Wyoming. Cyclogenesis is forecast to
continue as the jet streak rounds the base of an upper-level
trough and propagates into the Midwest. Look for the surface low
to strengthen through today as it move eastward along the
front. Increased ascent will lead to widespread showers and a
few thunderstorms over southern Minnesota initially spreading
northward into central Minnesota and northwest Wisconsin this
afternoon.

Modest instability is forecast with tall, skinny MLCAPE of
750-1250 J/kg forecast. Deep layer shear will be low, around 20
to 25 knots. This pattern will support mainly pulse storms which
may be capable of small hail to around half an inch in
diameter. Relatively deep warm cloud depths and ample moisture
through the column suggest a potential for locally heavy
rainfall where storms develop. In our area, the greatest threat
of locally heavy rain will be from the Brainerd Lakes east into
northwest Wisconsin and mainly this evening. Weak inflow layer
winds of 10 knots or less will limit moisture transport. The
surface front will remain south of our area, so the greatest
risk of heavy rain will likely develop farther south across
central and southern Minnesota into central and southern
Wisconsin. The WPC Excessive Rainfall Outlook highlights that
area clearly. Areas along the International Border have the
lowest chance of precipitation over the next 48 hours.
Temperatures today will top out in the middle to upper 70s.

The surface low is forecast to slowly advance east-
northeastward on Friday keeping rain chances over northwest
Wisconsin and the I-35 corridor to wrap up the week. Partial
clearing and weak cold air advection over Minnesota will support
a chance of showers and storms developing during the afternoon
over north-central and central Minnesota, including
International Falls, Grand Rapids, and Brainerd. Small hail will
be possible once again with any storms that develop along with
a chance of locally heavy rainfall.

The slow-moving system is forecast to pull away from the
Northland Friday night and Saturday. Lingering cold air
advection aloft will support a few isolated showers or storms
Saturday afternoon and evening. A shortwave trough will move
into the region from the northwest Saturday night and Sunday
which will support additional shower and storm chances through
the weekend.

Cool air aloft will persist into early next week keeping a
diurnal threat of showers and storms in the forecast until late
next week. Temperatures will generally remain near normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 640 AM CDT Thu Jul 4 2024

Rain showers and a few thunderstorms will spread northeastward
today and affect BRD and HYR this morning. They will arrive
later at DLH and HIB. Latest CAMs suggest a 1-2 hour window of
storm potential at BRD and HYR so I narrowed the timeframe for
VCTS with this update. MVFR to IFR ceilings develop at HYR
tonight and may also affect DLH.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 416 AM CDT Thu Jul 4 2024

Light westerly winds this morning will back northeasterly by
this afternoon and gradually strengthen in response to
developing low pressure over southwest Minnesota. Conditions may
become hazardous for small craft in the southwest arm of Lake
Superior, particularly near the Twin Ports. Look for winds to
strengthen to around 10 to 15 knots with gusts as high as 20
knots. Waves will build to 1 to 3 feet. If winds and waves trend
higher than currently forecast, a Small Craft Advisory may
become necessary. Winds and waves will gradually weaken on
Friday as the low pressure pulls away from the Northland. Expect
relatively light winds of 5 to 10 knots with gusts as high as
15 knots through the weekend.

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

&&

.HYDROLOGY...
Issued at 416 AM CDT Thu Jul 4 2024

A Flood Advisory remains in effect across portions of the Rainy
River Basin, extending as far east as Lac La Croix and as far
west as the Rainy Lake outlet. Lingering high water from rains
in June continue to be present across the Rainy River Basin. Far
headwaters gauges on the Kawishiwi River, Basswood River, and
Lake Vermilion have crested and indicate that the flood wave or
peak water levels are slowly making their way through the basin.
However, rises continue on the Vermilion River and Lac La Croix
and downstream of those points. This has led to high water and
some minor flooding on Crane Lake and Namakan/Kabetogama
(Nam/Kab) lakes, as well as lake levels increasing on Rainy
Lake. Per the latest IJC water level bulletin, dam operators
have pulled all logs at Kettle and Squirrel Falls, and continue
pulling logs at International Falls as conditions allow in order
to maximize outflow through the basin. However, the sheer
volume of water moving through the basin will still result in
rises on these lakes due to the natural constriction of the
flow. Vermilion River is forecast to crest late this week and
then begin slow recessions. Water level rises further downstream
on Nam/Kab are likely to continue (latest rates of rise have
been an inch or two a day, this is likely peak rates of rise and
should begin to slow by the weekend), with peak water level
early to mid next week. As is usual for this basin, water will
move slowly and recessions will happen at glacial speeds.
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, and
strong currents in constricted areas. Some northerly winds are
possible Friday, but are not expected to be strong, so wave
heights should be minimal. The Flood Advisory currently extends
through next Wednesday, but may need to be extended based on
observed conditions.

&&

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

&&

$$

DISCUSSION...Huyck
AVIATION...Huyck
MARINE...Huyck
HYDROLOGY...Huyck/Levens