Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 202337

Area Forecast Discussion
National Weather Service Duluth MN
637 PM CDT Fri Oct 20 2017

.SHORT TERM...(This evening through Saturday)
Issued at 334 PM CDT Fri Oct 20 2017

The Northland`s warm, southerly flow will continue through tonight
and into Saturday. A strong low-level jet (40 to 50 knots) will
develop tonight in advance of a mid/upper trough advancing across
the western US and a cold front moving into the Dakotas overnight.
The southerly flow will pump in a lot of moisture overnight, with
precipitable water values increasing from this afternoon`s 0.5"
to 1.0 to 1.25" by Saturday morning. Cloud cover will develop with
saturation overnight. Passing shortwaves could provide forcing
for some showers, and maybe a few thunderstorms. The model
soundings though suggest there may be some capping that could make
it difficult to realize the up to several hundred J/kg of most
unstable CAPE in the models. The winds and cloud cover will prop
up temperatures tonight, so it will only get down to the middle
50s to near 60 degrees for most areas.

Saturday looks cloudy and humid. The cold front will move into the
central and north-central MN in the late afternoon and early
evening. Showers and storms are possible during the morning and
afternoon across the whole Northland, but the chances for rain
will really ramp up across northeast MN in the very late afternoon
and early evening when the front begins moving into the region.
While it will be a breezy day, expect stronger gusts up to 35 mph
to be mixed down with any showers or storms considering the
strong flow aloft.

There is a low risk of strong to severe storms in the afternoon
and evening across northwest Wisconsin. There could be up to
around 1000 J/kg of most unstable CAPE and 30 to 35 knots of 0-6
km wind shear, so some storms could become supercells. The
strongest storms could produce hail, strong wind gusts, and brief
heavy rain.

.LONG TERM...(Saturday night through Friday)
Issued at 334 PM CDT Fri Oct 20 2017

Showers and even a few thunderstorms will linger into Saturday
evening, as a strong cold front and upper level trough moves
across the Northern Plains and Upper Midwest. A few of the storms
may be strong to severe, especially across northwest Wisconsin
Saturday evening. The precipitation will gradually end from west
to east Saturday night and early Sunday with generally dry weather
expected on Sunday. The dry weather will be short-lived, though,
as another shortwave pushes across the region from the Dakotas
into the Lake Superior region Sunday night and Monday. The upper
level trough will amplify across the western Great Lakes Monday
and Monday night, with upper level shortwave energy bringing
unsettled weather to the Northland. Some snow showers will even be
possible Monday night and early Tuesday, as colder air pours into
the area from Canada. This upper level low and amplifying trough
will dominate the weather across the Great Lakes region at least
into midweek. The GFS and ECMWF start to diverge considerably by
Wednesday, with fairly low confidence in any particular solution
at that time range. It appears the best chance of precipitation
throughout the long term period will be on Thursday and Thursday
night. High temperatures throughout the period will range from the
50s to lower 60s on Sunday and Monday, to the 40s and lower 50s
from Tuesday through Friday. Lows will fall from the 40s early in
the period, to the 20s later in the long term period.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 629 PM CDT Fri Oct 20 2017

A low pressure system over eastern Montana this afternoon will
move up into Saskatchewan and then on to northern Ontario through
the TAF period. Ahead of this system strong low level winds will
bring LLWS to the terminals for the first several hours of the
terminals, then diminishing in the 04z-12z time range. Lowering
clouds will come streaming into the area from the south, with MVFR
ceilings and rain showers moving in from south to north beginning
around 12z. Once the MVFR ceilings begin, they should continue
through the end of the TAF period. Some clearing is expected from
west to east afterwards.


DLH  56  63  46  58 /  40  70  80  10
INL  58  64  43  59 /  30  60  60  10
BRD  60  65  42  60 /  30  70  60   0
HYR  58  65  48  60 /  20  70  90  10
ASX  58  68  49  61 /  20  50  80  20


LS...Small Craft Advisory until 11 AM CDT Saturday for LSZ121-148.



SHORT TERM...Grochocinski
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