Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 231746

Area Forecast Discussion
National Weather Service Duluth MN
1246 PM CDT Sun Jul 23 2017

.SHORT TERM...(Today through Monday)
Issued at 423 AM CDT Sun Jul 23 2017

At 4 AM, GOES 16 imagery was indicating several layers of cloud
cover across the Northland, mixed with an area of mostly clear
skies from just east of the Brainerd Lakes into portions of the
Iron Range. Stratus had consumed areas near Lake Superior this
morning, with areas of fog reducing visibilities to as low as a
quarter mile in spots. Elsewhere, it was mostly cloudy from north
central Minnesota into the Arrowhead and far northern Wisconsin.
Temperatures were generally in the 50s to around 60.

The focus for today will be cloud cover, along with a chance of
lingering precipitation. The latest HRRR, along with water vapor
imagery, indicates the upper level low and vort max is currently
over the Minnesota Arrowhead this morning. The upper level low and
vort max are expected to slide off to the southeast today, but a
weak surface trough will linger across the area. High pressure
will slowly build in from the north and northeast today, allowing
skies to become mostly sunny across north central Minnesota and
the Arrowhead this afternoon. The clouds will hang on longest from
the Brainerd Lakes, into east central Minnesota and northwest
Wisconsin. The HRRR indicates the Twin Ports area and even
northwest Wisconsin should clear about mid afternoon, while the
clouds may hold on until later afternoon in the Brainerd Lakes.
With the surface trough in the area, and lingering moisture, will
hang on to some small POP`s, although placement is a bit tough to
nail down. Will tie POP`s closely to the location of the surface
trough. Highs today will generally be in the 70s.

While skies clear by tonight, this will give us an opportunity
for rather widespread fog. Will continue to mention fog across the
area tonight. Some of the fog may be dense, and we will need to
assess during the day, whether any dense fog advisories will be
warranted at some point. Overnight lows will be on the cool side
with much of the area dropping into the 40s to lower 50s.

With plenty of sunshine on Monday under high pressure, we should
see high temperatures in the 70s.

.LONG TERM...(Monday night through Saturday)
Issued at 423 AM CDT Sun Jul 23 2017

The main concern for the long term is the potential for strong
thunderstorms Tuesday and Tuesday night.

A shortwave trough is forecast over central portions of Alberta
and Saskatchewan Monday evening. Surface low pressure will
accompany the feature over central Saskatchewan with a cool front
extending southwest into the western Dakotas. The upper trough,
surface low, and cool front will progress eastward overnight.
Showers and thunderstorms are likely along the cool front as it
moves across the Canadian Prairies and North Dakota overnight,
moving into northwest Minnesota Tuesday morning. Ahead of the
front, surface high pressure will drift away from the Northland
allowing a tongue of warm and moist air to migrate northward into
the region. The overnight storms should be weakening by the time
they move into the Northland Tuesday morning. Partly cloudy skies
are expected over central Minnesota and portions of Wisconsin
during the morning with clearing expanding across the north by
mid-day. Diurnal heating of the warm, moist airmass over the area
will lead to moderate to strong instability by late afternoon and
early evening. Convergence along the front will increase as
southerly winds strengthen during the afternoon. Thunderstorms are
expected to redevelop over northwest Ontario, northern and
central Minnesota, and eastern South Dakota during the afternoon.
Severe weather is possible and 0-6km deep layer shear of 35 to 45
knots is forecast to accompany the storms, leading to storm
organization and a potential for upscale evolution into one or
more MCS. Temperatures will be near to slightly above normal for
Tuesday with highs near 70 degrees in far northeast Minnesota and
the lower 80s in our southwest.

The shortwave trough will move into far northern Ontario on
Wednesday with the cool front continuing southeastward out of the
Northland. Showers or a few thunderstorms are possible over
northwest Wisconsin, mainly during the morning, as the front exits
the area. An amplifying upper ridge over the Rockies will place
the forecast area in a northwest flow regime by Wednesday. The
ridge axis will drift slowly eastward through Friday morning, and
gradually flatten in response to a shortwave trough cresting the
ridge Thursday. Surface high pressure will drift through the Upper
Midwest and Northern Plains Wednesday through Friday morning with
dry conditions expected and near to slightly above normal
temperatures. The passing shortwave trough will move into the
Upper Midwest on Friday and may only be marked by a slight
increase in cloud cover during the afternoon hours. Rain chances
on Friday are around 10% based on the 00Z guidance and previous

Another shortwave trough will move through the northern Canadian
Prairies Friday night and Saturday. A surface low will accompany
the trough and push eastward across northern Saskatchewan and
northern Manitoba on Friday to near Hudson Bay by Saturday
morning. A weak cool front will advance southeastward into the
Upper Midwest during the first half of the weekend, which will
contribute to a slight chance of showers and thunderstorms.
Temperatures are forecast to remain near to slightly above normal.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1246 PM CDT Sun Jul 23 2017

MVFR ceilings should gradually lift to become VFR today at all TAF
sites, with the thick stratus deck being replaced by scattered VFR
stratocumulus from north to south, just about to the Iron Range
at 18z and should reach DLH by 00z, BRD by 02z, and HYR around
04z. This stratocu will dissipate after sunset with some MVFR to
IFR visibilities due to fog possible overnight at all sites,
except INL where VFR conditions will prevail. Very light northeast
winds today less than 10 knots, becoming calm tonight. Winds
increase out of the south to southeast Monday morning.


DLH  69  52  74  57 /  20   0   0  10
INL  75  53  79  60 /  10   0   0  30
BRD  73  53  77  63 /  10   0   0  20
HYR  71  51  77  58 /  10   0   0   0
ASX  66  50  75  55 /  20  10   0   0




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