Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 160546

Area Forecast Discussion
National Weather Service Duluth MN
1246 AM CDT Sun May 16 2021

.DISCUSSION...(This evening through Friday)
Issued at 340 PM CDT Sat May 15 2021

Summary: Scattered showers and isolated thunderstorms are expected
to continue this afternoon before coming to an end this evening.
Another round of showers will be possible for far northern MN
tomorrow. Otherwise, expect dry conditions and very warm temps to
round out the weekend and into the first half of next week. The
next chance for widespread rain arrives Wednesday.

A shortwave will cross the CWA this afternoon, developing scattered
showers and thunderstorms. Current radar observations show a few
thunderstorms have already developed in northeast MN. In addition,
small hail has been reported with the strongest cells. Model
soundings support these thunderstorms continuing this afternoon due
to CAPE values of 100-500 J/kg. The full amount of CAPE is unlikely
to be realized though since the profiles of CAPE are long and
skinny. This will allow entrainment to reduce the amount of
instability available to the cells that have already developed.
Regardless, these weak thunderstorms capable of producing small hail
are likely to continue into the late afternoon and early evening

Expect shower and thunderstorm chances to diminish this evening as
the shortwave moves east. Low dewpoint depressions and light winds
tonight into early tomorrow morning are likely to lead to fog
development across the CWA. Following the fog, Sunday should be a
quiet day for much of the area with highs in the low to mid 70s
inland, upper 50s to mid 60s near the lake. The exception will be in
the far northern CWA, where a brief injection of vorticity could
spark off scattered showers in the afternoon.

Next week will be a dramatic change in temperature due to a longwave
ridge building over the Northern Plains. This ridge will allow for
strong warm air advection across the CWA. Expect highs for much of
the week to be in the upper 70s to low 80s. The exception will be
areas adjacent to Lake Superior, where highs will remain in the 60s.
Precip chances for the latter half of the workweek will be
plentiful, as a series of shortwaves are likely to cross the area.
This will bring a chance of rain for all areas from Wednesday
through the remainder of the forecast period.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1246 AM CDT Sun May 16 2021

The main concern for the morning hours will be fog potential. The
greatest likelihood for fog will be across northwest Wisconsin,
including HYR, and also DLH where light onshore flow from Lake
Superior may increase chances for fog. Confidence is fairly low on
timing of fog onset and how low visibilities will drop due to
model uncertainty. It is likely that the fog will be patchy and
visibility restrictions may jump up and down from VFR down to MVFR
and possibly IFR through the night until just after sunrise. Fog
will lift Sunday morning, leading to prevailing VFR conditions. A
passing short wave may bring some scattered showers to INL during
the day.


Issued at 930 PM CDT Sat May 15 2021

An easterly component to the wind will help bring patchy fog
across Lake Superior and affect the near shore waters late tonight
through Sunday morning. The fog will dissipate shortly after
sunrise. Otherwise, with high pressure nearby, winds will be less
than 10 knots and waves less than 2 feet through Monday.


DLH  42  69  48  78 /  10   0   0   0
INL  44  76  51  83 /   0  10  10   0
BRD  46  75  50  79 /   0   0   0   0
HYR  43  73  45  79 /  30   0   0   0
ASX  39  69  46  79 /  20   0   0   0




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