Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 151756 AAC

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1256 PM CDT SAT OCT 15 2016

Issued at 1256 PM CDT Sat Oct 15 2016

Please see the new 18Z Aviation Discussion below.

UPDATE Issued at 921 AM CDT Sat Oct 15 2016

Updated to take out pre-first period and adjust temp/precip trends
based on current observations.


.SHORT TERM...(Today through Sunday)
Issued at 424 AM CDT Sat Oct 15 2016

We have very warm conditions across the area this morning, with
temperatures pushing record warm minimum values so far this
morning. Synoptically we are in the warm sector ahead of a cold
front. A surface low is over southern Manitoba, with the cold
front extending down into eastern North and South Dakota. A warm
front extends east from the low into Ontario. The southerly flow
over Minnesota and Wisconsin is keeping temperatures in the 50s
and low 60s so far this morning, about 20 degrees above normals
for this time of year. This has also brought a lot of low level
moisture and warm air advection lift into the area. It is not
quite deep enough though, and cloud bases remain above 1500 feet,
and there has not been any fog or drizzle development so far this
morning. Models depict this cold front sweeping east across the
forecast area during the day today, and developing showers and
even a few thunderstorms. As little has developed so far, most of
them are overdoing the early morning shower activity, but can buy
into the late morning and afternoon showers that develop across
the eastern half of the forecast area today and then drop
southeast ahead of the tonight. Have reduced the early morning
pops significantly and kept chance pops going for the afternoon. I
have also boosted temperatures ahead of the front, as it will not
take much to warm up with as warm as we are this morning, despite
the cloud cover. Tonight behind the cold front temperatures should
fall nicely in the evening as clouds clear from west to east. If
it was just for this morning, we would set some record warm min
temperatures, except we are going to fall into the 40s to mid 50s
by midnight tonight, setting our lows for today then instead of
this morning. Depending on the amount of lingering moisture, we
may have some patchy fog tonight and have included it in the
forecast for now. Most of Sunday should remain cool and dry, with
weak ridging moving east across the area. However, our next storm
system begins to move towards the area late on Sunday with some
potential for showers and even a few thunderstorms as the front
pushes back into our area from the southwest during the afternoon.
With the low developing to our west some strong east flow is going
to develop over Lake Superior, bringing cooler marine air onto the
North Shore and into the Twin Ports, so have cooled off highs for
those areas.

.LONG TERM...(Sunday night through Friday)
Issued at 424 AM CDT Sat Oct 15 2016

Will initially see an occluded system sweep across central Canada
late Sunday through Monday. The lows associated cold and warm
front will slide through the Northland. Decided to a mention of
thunderstorms ahead of the trailing cold front as the latest
GFS/NAM show a few hundred J/kg of CAPE. Bumped up low temps
heading into Monday as southerly flow will advect 50-60 degree
dewpoints into southern portions of the CWA. Think the GFS is
overdone bringing 50- 65 degree dewpoints to all of the Northland,
but will need to keep an eye on. If guidance trends towards the
GFS, will need to increase low temperatures heading into Monday
further. Right now there are some low 60s readings in the Hinckley
area. The coolest readings are in the Minnesota Arrowhead with
temperatures in the 40s.

After good agreement between guidance through most of Monday,
models diverge on the intensity and timing of a low that develops
across northern Wisconsin. The ECWMF/GFS are more progressive with
the feature, while the NAM/GEM are slower. Still expect some
shower and thunderstorm chances as Monday night into Tuesday as
the system moves through. Highs on Monday will be mild with
readings generally in the 60s across Minnesota and Wisconsin, a
few spots in northwest Wisconsin will see highs around 70. Lows
heading into Tuesday will fall into the 40s.

Good agreement between ECWMF/GFS aloft Tuesday through Wednesday.
A shortwave will exit the region into Quebec by Tuesday evening.
This will keep the Upper Midwest in quasi-zonal flow behind the
shortwave, while a long wave trough digs into the Northern Plains.
The trough will continue to dig on Thursday, but the GFS is a bit
slower to bring this feature along. The differences between
guidance continue late in the week as the GFS cuts off a low in
the Central Plains, while the ECMWF over the central Great Lakes.

Will see cooler temperatures from Wednesday through Friday with
highs generally in the 40s and overnight lows in the 30s and low


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1256 PM CDT Sat Oct 15 2016

Cold front stretched from southwest Minnesota into the Minnesota
Arrowhead at 18Z. The boundary will advance eastward across
northwest Wisconsin this afternoon and early this evening. MVFR
ceilings and scattered rain showers were found ahead of the front,
mainly affecting DLH and HYR. Much drier air was found behind the
boundary and ceilings quickly lift to VFR after frontal passage.
VFR conditions are expected to prevail for the remainder of the
forecast period, except at HYR where a period of MVFR fog is
possible overnight. Winds may remain higher overnight than
expected. Should winds stay up at HYR, fog potential would
diminish significantly. Winds will eventually veer northeasterly
and then easterly overnight and early Saturday. Upslope flow off
Lake Superior at DLH could result in low stratus development after
16.14Z. Not confident enough with this package to add ceiling, but
did include SCT. Overall confidence with this forecast is above


DLH  65  44  58  51 /  30   0  10  70
INL  63  40  60  49 /  10   0  20  60
BRD  65  43  64  58 /  10   0  10  60
HYR  66  44  67  58 /  40   0   0  70
ASX  66  46  61  54 /  20   0   0  70


.DLH Watches/Warnings/Advisories...


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