Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 250552 AAC

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1252 AM CDT Sun Jun 25 2017

Issued at 1252 AM CDT Sun Jun 25 2017

Update for new 06Z Aviation Discussion below.

UPDATE Issued at 936 PM CDT Sat Jun 24 2017

Embedded pieces of energy are rotating through the forecast area
and will do so through the night. Periodic showers are expected
through the night and have adjusted pops to reflect trends from
latest radar, as well as short term hires models. Rest of the
forecast in good shape.


.SHORT TERM...(This evening through Sunday)
Issued at 248 PM CDT Sat Jun 24 2017

The Northland will remain under the influence of an upper-level
trough tonight and through the day Sunday. A mid-level trough with
a concentrated positive vorticity maxima will translate to the
east- southeast this evening away from the region, and the low-
level band of frontogenesis will also begin to pivot to the west.
By Sunday morning, a band of channeled vorticity associated with a
secondary shortwave trough will enter the Northland. This will
once again bring more chances of showers and possibly a
thunderstorm for Sunday. Lift will be enhanced as a corridor of
low-level frontogenesis will once again be present due to a
baroclinic zone developing ahead of a push of cold air advection.
More chances of thunderstorms will be possible as low-level lapse
rates steepen during the late morning and afternoon hours.
However, just like today, instability looks to be pretty meager,
with values of MUCAPE between a few hundred up to 1000 J/kg,
depending on the model. Model soundings show some shallow and thin
CAPE profiles, so again a thunderstorm cannot be ruled out, but
not expecting anything severe. However, there could be some
occasional lightning and small hail possible for Sunday, given the
low freezing level. This wave will eventually move off to the
east by the evening and overnight hours Sunday.

With the cold air advection and abundant cloud cover,
temperatures will once again be well below seasonal average for
Sunday, with high temperatures ranging from the upper 50s over the
BWCA and Minnesota Arrowhead regions, to the lower to mid 60s
over north-central Minnesota and across our southern areas,
including northwest Wisconsin. This is about 10 to 15 degrees
below average, so temperatures will once again be close to record
low highs Sunday.

.LONG TERM...(Sunday night through Saturday)
Issued at 248 PM CDT Sat Jun 24 2017

The pattern will shift from northerly flow aloft over the region
to quasi-zonal by mid-week as several shortwaves move through in
the northern stream. Upper troughing is forecast to move into the
central CONUS late in the week into Saturday.

The models are in better agreement in general but do show
significant timing and track differences with the various
shortwaves which will have an impact on the Northland`s weather.
The best agreement comes early, Sunday night into Wednesday. A
shortwave will continue to move through the Northland with showers
and a few thunderstorms continuing Sunday night with chances
highest over far eastern areas. High pressure over the Northern
Plains Sunday night will slowly move east toward western Minnesota
on Monday. A weak shortwave/trough may still cause some showers
on Monday, mainly over the Arrowhead and parts of northern
Wisconsin. It`s possible we may have to spread some low POPs
further west but will hold off on that for now. Highs Monday will
be in the sixties to around seventy.

The high will pass east of the Northland Monday night into
Tuesday morning allowing the low level flow to become southerly.
This will bring in warmer air and should also result in more
sunshine. We expect highs in the seventies.

A stronger shortwave and low pressure system will move through
the Northern Plains Tuesday night into Minnesota on Wednesday then
continue east Wednesday night. We ramp up POPs from west to east
Tuesday night into Wednesday. There remains a chance for some
strong storms Tuesday night with strong/severe storms possible
Wednesday into Wednesday evening.

There will be periodic chances for showers/storms Thursday
through next weekend as several more shortwaves are forecast to
affect the region. There will likely be some dry periods but with
all the model uncertainty, it`s too difficult to determine when at
this time. Temperatures will be near or below normal.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1252 AM CDT Sun Jun 25 2017

A few lingering showers are present across the region, in
particular KINL. Focus for the next six hours are on a shortwave
feature moving into the forecast area that will impact the
majority of sites with rain, reduced visibility, and lower
ceilings. Many sites will get down into MVFR or IFR conditions and
the consensus blend of short term guidance was handling the
ceilings best as of late. Concerned with the ceilings at KHIB
getting down to LIFR so added a TEMPO for overcast at 300 ft. Some
gusty winds are possible Sunday, particularly in the afternoon
across multiple sites.


DLH  49  60  46  68 /  40  70  50  10
INL  49  60  43  69 /  80  70  20  10
BRD  49  64  45  70 /  30  20  10   0
HYR  48  63  45  68 /  40  70  40  20
ASX  49  63  46  69 /  60  70  50  10




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