Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 170533
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1233 AM CDT Thu May 17 2018

.SHORT TERM...(This evening through Thursday)
Issued at 316 PM CDT Wed May 16 2018

A cold front was moving through northeast Minnesota at 19Z with
plenty of cumulus clouds ahead of it. Showers and a few
thunderstorms were also forming in an area of FGEN from 1000-850mb
along the south shore of Lake Superior. This was in concert with
MUCAPE values approaching 1000 J/kg. However, some MLCIN up to 150
J/kg was also in the vicinity and should keep the storms in check.
Effective bulk shear was 25 knots which will keep the storms moving
along. The storms will move into northwest Wisconsin and diminish
over northeast Minnesota by 7pm, then end in northwest Wisconsin by
10pm as forcing diminishes with loss of daytime heating.

The cold front becomes a warm front late tonight and begins to lift
back to the northeast. The front will be located from northwest
Minnesota to the Twin Ports and along the south shore by 4am. This
will be in an area of FGEN in the 850mb layer. Latest short term
models are pointing toward some thunder, but not enough agreement
amongst models to warrant a mention.

The 850mb layer of FGEN remains over far northern Minnesota through
the day Thursday. Meanwhile, the warm front slowly pushes north. A
ridge of high pressure begins to nose its way through western Lake
Superior while stabilizing the atmosphere near the lake. Mid level
ridging also begin to work over the area in the afternoon. This
combination will lead to the best chance of rain occurring along and
north of U.S. Highway 2 in Minnesota. Elsewhere, small chances as
the best forcing has moved on and will largely be driven by diurnal
heating. Max temps will be cooler Thursday as the flow turns
easterly as the high pressure ridge becomes anchored over Lake
Superior. May see some thunder late in the afternoon from the
Brainerd Lakes to the Pine City area.

.LONG TERM...(Thursday night through Wednesday)
Issued at 316 PM CDT Wed May 16 2018

Thursday night will find the Northland on the northwest periphery
of a mid-level ridge as a shortwave trough kicks northeastward
from the Dakotas across northern Minnesota. Isentropic ascent is
forecast over the frontal surface aided by low-level confluent
flow and divergence aloft. The frontal boundary will lift
northward into Ontario Friday morning with isentropic ascent and
convergence will linger over northwest Minnesota and portions of
northwest Ontario. Rain showers, and possibly a few
thunderstorms, can be expected from Thursday night into Friday
morning, mainly over our western and northern zones, where ascent
will be strongest. The confluent flow in the low levels, with
divergence aloft will continue through Friday and Friday night
keeping a chance of rain in the picture. Another shortwave trough
will move through the northern Canadian Prairies and through
northwest Ontario late Friday night and Saturday, which will push
the precipitation chances farther east. Continued a consensus
approach to POPs/QPF through Saturday night.

High pressure builds into the Northland as the mid- and upper-
level ridging moves into the region Sunday. Thunderstorms are
forecast over the Plains early next week. The GFS and GEM are
latching onto that potential and produce convectively driven
perturbations which grow upscale and drift eastward toward the
Mississippi River Valley. The initial development and eventual
evolution of any convectively driven disturbances is suspect, but
there is a slight chance of a few showers Sunday night through
the middle of next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1227 AM CDT Thu May 17 2018

A cold front draped east to west across MN and WI south of the
terminals has produced a field of northeast winds across the
terminals, sustained in the 10-15kt range with VFR conditions
through at least 18z. After 18z the front moves back north again,
serving as a focus for more showers and thunderstorms. This
convection is expected to affect mainly KDLH, KHIB and KINL. For
now have included only VCTS and will have to wait to see how
things develop before including more details.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  41  54  39  70 /  20  30  10  10
INL  40  63  42  73 /   0  40  50  40
BRD  48  73  50  78 /   0  20  10  10
HYR  46  74  48  79 /  30  20  10   0
ASX  40  56  40  76 /  30  20  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 4 AM early this morning to 4 AM CDT
     Friday for LSZ142-143-146-147.

     Small Craft Advisory until 4 AM CDT Friday for LSZ144-145-148.

&&

$$

SHORT TERM...GSF
LONG TERM...Huyck
AVIATION...LE



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