Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 220817
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
317 AM CDT Thu Jun 22 2017

.SHORT TERM...(Today through Friday)
Issued at 316 AM CDT Thu Jun 22 2017

The forecast area was under the influence of a col at 0730Z. High
pressure was located to the east and west of the area, with low
pressure to the north northwest and to the southwest. An occluded
front was connecting the two areas of low pressure and was just
entering the western edge of the region. First round of showers and
storms was ending and exiting. Some fog was forming where the sky
had cleared. The clearing will be short lived as more clouds
upstream in the Dakotas prepares to move into the region.

Next round of showers, with a few isolated storms will move into the
southern edge of the forecast area around 12Z/7am. This batch is
associated with a vorticity maxima moving quickly eastward in the
fast quasi-zonal flow aloft. The storms should stay south of the
area as supported by latest short term hires models through noon. In
the afternoon, some storms will likely drift along the southern edge
of the region, roughly from near Winter, WI, to Fifield and
Phillips. Additional shower activity should develop late in the
afternoon from northern Cass and Aitkin counties north to the
Borderland. This also noted in the ARW/NMM/HRRR as well as NAM/GFS
as an upper trof approaches.

Made no change to the pops for tonight as NAM/GFS indicate the
aforementioned showers will drift over the northern two thirds of
the forecast area, then mainly along the Borderland overnight in the
vicinity of an elongated/channeled area of vorticity.

On Friday, a vigorous vort max, in the base of an upper level trof,
will swing past the international border region. As the mid and
upper level flow turns northwesterly, cold air advection begins.
Some spotty showers are expected to develop as noted by the ARW/NMM.
The other deterministic models also point to some showers.
Thermodynamic profiles are borderline for the mentioning of thunder
and will leave out. Max temps on Friday will be below average.

.LONG TERM...(Friday night through Wednesday)
Issued at 316 AM CDT Thu Jun 22 2017

The Northland will be in a cool weather pattern over the weekend
into Monday. High temperatures will only be in the low to middle
60s, about 10 to 15 degrees cooler than seasonal normal. A few days
of northwest flow and passing shortwaves and upper troughs will mean
periods of showers and weak storms, especially during peak heating.
The strength of the solar heating is quite strong for this time of
the year. Combine that heating of the surface with the cool air, and
it will not be difficult to develop instability for scattered to
broken afternoon and early evening cumulus and light showers. The
GFS and NAM most unstable CAPE also suggest there may be enough
instability for rumbles of thunder in the afternoon. While large-
scale forcing does not look particularly good for generating much
thunder, those shortwaves would help generate thunder, and there are
model differences in the track and timing of the waves at this
point. Think it best to just maintain a low chance of thunder for
the afternoon and early evening hours of both Saturday and Sunday.
Drier air will likely move into the Northland Monday as high
pressure approaches from the west, but there could be enough
moisture to get light showers and storms over the eastern Arrowhead
and the far southeast forecast area in northwest Wisconsin. The
drier air will mean more sunshine for Monday, so temperatures will
at least rebound to highs closer to 70 degrees.

High pressure will likely move through the Northland Monday night
and/or Tuesday, providing a period of clear skies. Temperatures
should warm back up to near seasonal temperatures in the middle 70s.
Southerly return flow will then set up late Tuesday into Wednesday
when an upper-level ridge moves into the region and low pressure
continues to approach from the west. Both the GFS and European
indicate a potential wet and stormy period around this time, or
shortly after. However, the GFS is significantly faster than the
European, with showers and storms moving into the Northland
Tuesday night. The European holds it off until Wednesday night.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1239 AM CDT Thu Jun 22 2017

A cold front will continue to move slowly across the Northland
overnight, generating scattered showers and a few thunderstorms.
The best chance of showers and thunderstorms will be in an area
from KBRD to KDLH and into KHYR as well. High pressure will move
in behind the front, with mainly dry conditions expected for
Thursday and Thursday evening. Mainly VFR conditions are expected
throughout, although some MVFR CIG`s and VSBY`s will be possible
at times, especially at KHYR.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  73  52  66  48 /  10  20  20  10
INL  73  50  62  47 /  20  30  40  40
BRD  75  53  65  47 /  10  10  10  10
HYR  73  53  69  48 /  50  20  20  10
ASX  74  54  69  50 /  20  20  20  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

SHORT TERM...GSF
LONG TERM...Grochocinski
AVIATION...DAP/Grochocinski



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