Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 161204

Area Forecast Discussion
National Weather Service Duluth MN
604 AM CST Thu Feb 16 2017

.SHORT TERM...(Today through Friday)
Issued at 345 AM CST Thu Feb 16 2017

A ridge of high pressure over the area early this morning is
sliding off to the east as a warm front and trough of low pressure
develops over the eastern Dakotas. Aloft, there is a significant
baroclinic zone developing over Minnesota, oriented in a north-
south fashion. Significant warm air advection is occurring along
this baroclinic zone this morning, and is expected to continue as
the zone slowly shifts east across Minnesota and Wisconsin. As
happened yesterday, the hi res models are once again picking up on
some potential for snow showers within the baroclinic zone as a
weak ripple moves through the flow. Agreement is a little better
than yesterday, so have gone ahead and included some small pops in
the forecast for portions of the area during the morning and early
afternoon, though I expect that adjustments will need to be made
as the band has yet to develop upstream. With the warm air
advection going on have gone on the warmer end of guidance, with
most locations getting up into the 30s with only some upper 20s
for the tip of the arrowhead. The baroclinic zone shifts east of
the forecast area this evening, so feel comfortable going with a
dry forecast overnight tonight, and the warm air should keep our
mins on the mild side. Of concern is the potential for stratus
clouds developing in this warm air advection regime with snow melt
going on to contribute to low level moisture, and the NAM12 has
picked up on this pretty strongly. However, it indicates stratus
should already have formed over eastern North Dakota this morning,
and since it`s not there, this is definitely overdone. Have
instead gone more with the GFS which delays stratus development
until tonight at least, which again may still be too aggressive.
Have kept cloud development minimal for now until we can get a
better handle on the if/when of them. This also leaves us with a
dry forecast and perhaps enough sunshine to boost temperatures
over what we already have in the forecast. For now have gone on
the warm end of guidance for Friday in our south where snow cover
is already pretty low, and have gone more towards consensus where
we should still have a respectable snowpack.

.LONG TERM...(Friday night through Wednesday)
Issued at 345 AM CST Thu Feb 16 2017

The upper level ridge directly over the CWA 00Z Saturday will push
off to the east, as an upper level shortwave slides along the
international border region. Contemplated adding a small chance of
precipitation to the northern quarter of the CWA for Friday night,
but will hold off at this point as it looks as if it would be very
light if anything. The shortwave will move quickly out of the region
early Saturday, allowing heights to build again in the wake of this
shortwave. Will need to watch for the continued development of
stratus and possibly some drizzle or freezing drizzle late in the
week due to warmer temperatures, and melting snow. Forecast
soundings continue to hint at that possibility, which would impact
high temperatures considerably. The development of a major trough in
the western states will result in a sharp upper level ridge by
Sunday, but the trough, and attendant Gulf moisture will start to
affect the Northland already by Monday. The models are in somewhat
better agreement concerning the evolution of what could be a fairly
decent rainfall event from Monday into Monday night. Will continue
with fairly high POP`s across the area, at least from Monday
afternoon through Monday evening. May even need to consider adding
thunder mention at some point, especially in the south. The upper
level flow will generally flatten in the wake of the Monday and
Monday night system, with dry weather and fairly small chances of
precipitation for the rest of the long term period. High
temperatures from Saturday into Monday are expected to be in the 40s
to around 50, with temperatures settling back into the 30s by next
Thursday. The highs from Saturday to Monday will generally be some
20 degrees above normal for this time of year.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 602 AM CST Thu Feb 16 2017

VFR conditions are expected across the Northland throughout the
day, as high pressure generally remains in control. There is a bit
of a question as to whether we will see the development of stratus
and light fog tonight. The NAM and to some extent the GFS do hint
at lower clouds and possible fog/drizzle developing tonight, as
moisture from melting snow is trapped beneath a low level
inversion. Will continue to mention MVFR and even localized IFR
CIG`s and VSBY`s tonight across the TAF sites.


DLH  34  26  45  31 /  20   0   0   0
INL  36  26  44  31 /  20   0   0  10
BRD  41  28  53  31 /   0   0   0   0
HYR  36  25  48  30 /  20   0   0   0
ASX  36  26  45  32 /  20   0   0   0




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