Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 131728

Area Forecast Discussion
National Weather Service Duluth MN
1228 PM CDT Tue Mar 13 2018

Issued at 1222 PM CDT Tue Mar 13 2018

Updated for the 18z Aviation Discussion below.


.SHORT TERM...(Today through Wednesday)
Issued at 308 AM CDT Tue Mar 13 2018

It will be another couple days of relatively mild and sunny
weather. High pressure will move through the Northland today,
warmer air will move in from the west, and a weak cold front will
move through the Northland late tonight and Wednesday morning.
There will lingering light lake effect downwind of Lake Superior
in northern WI this morning. Leaned on the warmest model guidance
for high temperatures today and tomorrow since it is that time of
the year where sunshine on the pine trees can result in
substantial warming and models tend to underestimate that warming.
Highs should generally range be in the 30s today, and upper 30s
and low 40s Wednesday.

.LONG TERM...(Wednesday night through Monday)
Issued at 308 AM CDT Tue Mar 13 2018

Wednesday evening and early Thursday some lingering Lake Effect
snow showers may affect the south shore of Lake Superior east of
Ashland. A ridge of high pressure will slowly build into the area
on Thursday, gradually shutting off the Lake Effect snow showers.
Otherwise the weather should be quiet with temperatures near

For the last few days we have been watching the development of a
large upper low off the west coast. This feature is beginning to
finally get close enough to the coast to begin sampling it with
the upper air network, so we have finally seen an improvement in
the model spread for this upcoming weekend. By Friday morning a
leading wave will eject out of that upper low out across the
Central Plains, bringing what will undoubtedly be a few days of
active weather late this week for Kansas, Oklahoma and the Mid
Mississippi/lower Ohio river valley area. However, this system
will stay too far south to affect us and ridging will build in at
the surface for Friday and Saturday. Have increased the diurnal
range both Friday and Saturday as I expect some sunshine and our
trees to bump up daytime highs, and the surface ridging should
produce enough radiational cooling to drop overnight lows into the
10-20 degree range.

The main upper low is not done puzzling us though, as it moves
across the Rockies and moves out onto the plains late Sunday and
Monday there are some differences in speed and track, some of
which may bring some precipitation chances to the area for Monday
and Tuesday, though most of the models are sticking to a more
southerly track in the wake of the preceding wave. Thus, have kept
some small chance pops going for Monday and Tuesday, but do not
have a lot of confidence in these. Have also kept temperatures
close to guidance and near normal.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1228 PM CDT Tue Mar 13 2018

VFR conditions will continue through the 18z TAF period as surface
high pressure lingers over the Dakotas. Winds should be gusty over
KHYR this afternoon, but should diminish by the evening as the
high pressure approaches. A mid-level shortwave trough and
associated cold front will dive southward over the region by late
Wednesday morning, which could bring some lower ceilings near the
end of the TAF period. Model guidance is uncertain if these
ceilings will lower to MVFR categories, so left them out for now.
Low-level wind shear will be possible for some TAF sites as the
front moves through, as surface winds weaken.


DLH  36  19  39  16 /   0   0   0   0
INL  40  18  39  10 /   0   0  10   0
BRD  39  18  41  16 /   0   0   0   0
HYR  35  16  42  16 /   0   0   0   0
ASX  32  18  39  18 /  30   0   0  20




SHORT TERM...Grochocinski
AVIATION...JTS is the U.S. government's official web portal to all federal, state and local government web resources and services.