Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 311144
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
644 AM CDT WED AUG 31 2016

.UPDATE...
Issued at 644 AM CDT Wed Aug 31 2016

Removed the fog wording over a portion of the forecast area where
surface obs no longer show fog. Clouds are still on tap to drift
south of the international border within the next few hours. Rest
of the forecast on track.

&&

.SHORT TERM...(Today through Thursday)
Issued at 253 AM CDT Wed Aug 31 2016

High pressure was located over northwest Manitoba at 07Z/2am.
Meanwhile, an upper level trof was rotating around a closed upper
low that was exiting Ontario. This trof has plenty of moisture
associated with it, from 3500 to 7800 feet, according to the Pickle
Lake, Ontario, 00Z/7pm sounding. The associated cloud cover with
this trof was dropping southeastward and was just north of the
international border. Some erosion was noted via satellite imagery
as it reached the drier airmass over the forecast area per the 00Z
sounding from INL. Some patchy fog was also forming over portions of
the area due to the light winds and the low level moisture from the
recent rains. Have a mention of fog until 13Z/8am over much of the
region. Bumped up the cloud cover to account for the clouds which
will drop over the area as the upper trof swings through. Some of
the models are pointing to some showers developing from the
Arrowhead to near the south shore of Lake Superior. The consensus at
this time is for no showers and will leave out. There have been a
couple of showers north of Pickle Lake/CYPL and have ended. Will
have to monitor to see if a mention is needed with later updates.

Another shortwave trof is progged to drop southward over the
Arrowhead and the eastern Wisconsin zones tonight. With moisture
still in the same layer as earlier, expect a bit more cloud cover
and have adjusted. Models keep out the possibility of any showers as
the dry low levels win out and should erode anything that attempts
to form. The surface high moves into northwest Ontario with the
ridge axis virtually overhead by 12Z/7am Thursday. Went with cooler
temps, but the cloud cover may have an impact on radiational cooling.

The upper trof departs on Thursday morning, with upper ridging
moving into the area in the afternoon. The center of the surface
high moves over Hudson Bay. This results in a northeast flow over
Lake Superior into the Twin Ports and northwest Wisconsin. The
northeast wind will turn to the southeast Thursday afternoon from
the Arrowhead into the Brainerd Lakes to the Borderland. A bit more
cloud cover is expected from the Arrowhead into northwest Wisconsin.
Coolest max temps will be near Lake Superior with 60s expected, with
lower 70s well inland from the lake.

.LONG TERM...(Thursday night through Tuesday)
Issued at 253 AM CDT Wed Aug 31 2016

The extended period will start out with the Northland under the
influence of a strong upper ridge that will extend through the
Northern Plains to Hudson Bay. At the surface, an area of high
pressure will cover the area. These features will gradually shift
east of the Northland Friday night into Saturday. A southerly flow
will then develop Saturday into next week allowing for moisture to
increase and for several shortwaves to move through the region.
Tropical Depression Nine will end up having some impact on the
regions weather. As it leaves the tropics and moves northeast just
off the eastern CONUS coast, it may slow the progression of the
ridge and keep the region under the southerly flow longer.

Thursday night into much of Saturday should be mainly dry. The
increasing moist southerly flow on Saturday may be enough to cause
some showers/storms over far western areas, but a better chance will
then develop Saturday night into at least early next week. Although
there still is quite a bit of uncertainty regarding the details, the
period from Sunday into early next week could feature chances for
strong to severe storms along with some heavy rain.

Temperatures Friday and Saturday will be from the lower seventies to
around eighty with lower to mid seventies Sunday and Monday. It
should be a bit cooler Tuesday into Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1259 AM CDT Wed Aug 31 2016

Skies will remain clear with light winds overnight as high
pressure builds into the region. This along with recent
precipitation has resulted in radiation fog development. Expect
fog to develop at all terminals except for KDLH overnight.
Generally think that visibilities will remain in the MVFR range
with a few periods of IFR at KHIB/KBRD. Will see fog lift around
11Z-12Z. After this expect VFR conditions at all site for the rest
of the forecast with winds less than 10 kts. The only exception is
there will be a period between 12Z-15Z where KINL will see MVFR
ceilings due to stratus moving in from the north. Expect the
stratus ceilings to lift to around 4 kft as the mixed layer
develops.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  72  49  68  50 /   0   0   0   0
INL  70  46  73  50 /   0   0   0   0
BRD  75  52  74  53 /   0   0   0   0
HYR  73  49  70  48 /   0   0   0   0
ASX  72  51  68  48 /   0   0   0   0

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...GSF
SHORT TERM...GSF
LONG TERM...Melde
AVIATION...WL


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