Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 281732

Area Forecast Discussion
National Weather Service Duluth MN
1232 PM CDT Tue Mar 28 2017

Issued at 1232 PM CDT Tue Mar 28 2017

Updated for the new 18Z Aviation Discussion below.

UPDATE Issued at 1223 PM CDT Tue Mar 28 2017

Update to boost afternoon temps about 5 degrees in most areas.
Looks like east winds will keep things cooler near the lake.


.SHORT TERM...(Today through Wednesday)
Issued at 311 AM CDT Tue Mar 28 2017

Dry and quiet conditions expected through the short term.

A weak shortwave trough associated with an area of cyclonic
vorticity advection was located over eastern North Dakota and
southeast Manitoba early this morning. The combination of mid-
level height falls ahead of and weak warm advection behind the
trough was supporting some mid-level stratus and an area of virga
over northwestern and portions of north-central Minnesota. At 3 AM
temperatures were in the middle 20s in northeast Minnesota and
inland portions of northwest Wisconsin. to the upper 30s at
Birchdale and International Falls.

The stratus is expected to spread eastward across northeast
Minnesota this morning. The 28.00Z INL sounding indicated a very
dry layer from the surface to 700 mb, so do not expect any of the
precipitation aloft to reach the ground today. In areas where
skies remain clear, patchy fog is expected before sunrise. Think
temperatures will continue to cool into the low 20s northeast and
for inland portions of northwest Wisconsin, and the middle to
upper 30s under the stratus over the northwest. Highs today will
trend a little cooler in the north due to the cloud cover, and a
touch warmer south. Temperatures should top out in the middle 40s
northeast to around 60 degrees in central Minnesota. Areas along
the Lake Superior shore may see a lake breeze develop this
afternoon, which would limit temperatures to the low 40s within a
few miles of the lake.

A trough of low pressure is forecast to move across the Northern
Plains and into the Upper Midwest tonight and Wednesday. Clouds
will spread eastward across the Northland with the trough.
Deterministic and ensemble guidance keeps the best forcing for
ascent both north and south of the forecast area, so kept
Wednesday dry as well. Winds near the surface and aloft will veer
more southerly during the period. Clouds will arrive in our
western zones overnight, which should keep lows a little warmer.
Still trended lows a few degrees cooler than the consensus blends
in the west, and around 5 degrees cooler for inland portions of
northwest Wisconsin. The increasing cloud cover will also keep
temperatures on Wednesday a little cooler. Think the consensus
blend was too cool, however, and trended temperatures toward the
warmer guidance members, especially in northeast Minnesota and the
eastern portions of our Wisconsin zones.

.LONG TERM...(Wednesday night through Monday)
Issued at 311 AM CDT Tue Mar 28 2017

Model differences begin immediately at the start of the long
term. Models disagree on the evolution/depth of a short wave
trough in the northern stream and the amount of phasing with the
cut off low in the southern stream. The GFS is weaker with the
shortwave trough/phasing with the southern stream. The ECMWF has a
sharper trough and better phasing with the southern stream. The
GEM is similar to the GFS. Regardless, surface ridging covers the
forecast area Wednesday evening and have a dry forecast. Late
Wednesday night through Thursday morning, the ECMWF/GFS bring QPF
to the southeast corner of the area and adjusted POPs as the
system moves nearby. Thursday afternoon through Friday finds the
ridging prevailing over the region as the aforementioned system
has departed. Friday night and Saturday finds a potent shortwave
moving across the forecast area. It`s associated surface
reflection moves over northern Minnesota. This will bring a
rain/snow mix to the international border area Friday night, then
change to all rain on Saturday. The GFS is the fastest at moving
this feature off to the east, the ECMWF/GEM are slower and keep
some QPF around through Saturday night. Used a blend leaning more
heavily on the GFS solution and have a dry forecast Saturday
night. Upper level and surface ridging return Sunday while the GEM
has an area of low pressure moving along the international border
area. The GFS also has this feature, but is up to 12 hours
slower. Used a blend through Monday to account for a growing
divergence amongst the models.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1232 PM CDT Tue Mar 28 2017

High pressure will continue to promote clear skies and light wind
speeds today. Light easterly flow will develop late today and
tonight and there are some model indications there could be some
cloud cover in the 1 to 3 kft range late tonight and early
Wednesday. The RAP, NAM, and GFS models are indicating some
saturation within that layer late tonight. The KHYR has the best
chance of seeing MVFR ceilings, and my confidence is high enough
to include it within the latest forecast. The KDLH area could get
it, too, but not as confident to forecast it yet.


DLH  58  28  45  29 /   0   0  10  10
INL  53  29  51  30 /   0   0   0  10
BRD  60  30  52  32 /   0   0   0   0
HYR  57  29  51  30 /   0   0  10  10
ASX  50  25  46  28 /   0   0   0  10




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