Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 281137

Area Forecast Discussion
National Weather Service Duluth MN
637 AM CDT Fri Jul 28 2017

.SHORT TERM...(Today through Saturday)
Issued at 426 AM CDT Fri Jul 28 2017

A large ridge of high pressure over Lake Superior early this morning
is expected to drift slowly south over the next 24 hours. The tight
upper low over Michigan that brought evening showers and
thunderstorms to the area has shifted far enough east that I expect
a dry afternoon and evening today, though we should have a decent
cumulus field with bases around 6 to 9kft.  Of greater concern in the
next few hours is the fog. A few locations, including Brainerd,
Ashland and Longville have been reporting dense fog, with several
other locations reporting 1 to 3 miles.  On the GOES-16 night-micro
data as well as the classic fog product there is a band of
stratus/fog that has developed over northwest Douglas county, likely
along the terrain ridge there. Some of this is onshore flow from the
lake, but all the rest of it is radiational fog. The higher clouds
drifting across our southwest may help dissipate some of the fog,
but otherwise I expect worsening conditions towards dawn.  May need
to issue a dense fog advisory if it gets any more widespread.

Tonight the surface ridge shifts only a little farther south, so
expect another radiational fog night, though likely with less dense
fog than this morning.  Lows to be slightly warmer than this morning
as well.

Saturday the southerly flow increases over the area as the surface
ridge shifts farther east.  A cold front will slowly develop out
over the Dakotas and up into Manitoba late tonight and into
Saturday. This feature should cause a plume of instability and
convergence to form over the eastern Dakotas and far western
Minnesota on Saturday. This may produce some showers and
thunderstorms that may move into the far western forecast area as
early as Saturday afternoon, but do not have very much confidence in
that and have kept pops low.

.LONG TERM...(Saturday night through Thursday)
Issued at 426 AM CDT Fri Jul 28 2017

Overall a fairly quiet weather pattern on tap for the end of July
into early August. A few low chances for showers and storms -
Saturday night into Sunday, then again Monday night into Tuesday -
but no significant widespread chances for precipitation in the long-
term pattern. Temperatures slightly above normal this weekend into
early next week, then a bit cooler with temperatures closer to
seasonable mid to late week.

On the synoptic scale there will be a pair of mid-level shortwave
troughs that move east across southern Canada this weekend into
early next week responsible for aiding in large-scale lift as
associated surface fronts build east/southeast into the area.
Neither scenario looks to produce much of a risk for strong to
severe storms nor widespread measurable precipitation. Temperatures
warmer than normal through the weekend into early next week with
highs in the low to mid 80s Sunday through Tuesday, except cooler
along the north shore.

Late week a broad area of high pressure builds in across the Great
Lakes region resulting in near normal temperatures and little chance
for precipitation, though afternoon cu and a few showers/storms much
like what happened yesterday and the day before cannot be ruled out.
Highs in the 70s, except cooler along the north shore on


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 638 AM CDT Fri Jul 28 2017

Morning fog will quickly dissipate this morning resulting in
mostly sunny skies and VFR conditions through much of the TAF
period at all sites. Some mid and high level VFR clouds possible
today with a light and variable wind due to high pressure to the
east. Tonight patchy fog is possible in a few spots, most likely
to impact HYR with MVFR to IFR visibilities towards midnight or


DLH  79  56  81  60 /   0   0   0  10
INL  82  58  84  61 /   0   0  20  30
BRD  81  59  81  61 /   0   0   0  20
HYR  81  54  82  57 /   0   0   0  10
ASX  79  54  83  59 /   0   0   0  10




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