Area Forecast Discussion
Issued by NWS Duluth, MN

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186
FXUS63 KDLH 181958
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
258 PM CDT Fri Aug 18 2017

.SHORT TERM...(This evening through Saturday)
Issued at 257 PM CDT Fri Aug 18 2017

An upper level trough was over the region this afternoon with a
weak low level trough near or just west of our CWA. Isolated to
scattered showers/storms have developed over/near the Walker/Pine
River/Brainerd Lakes region with more just entering Koochiching
County as of 1950Z. MLCAPE values are between 500J/KG and 1000J/KG
over the western half of Minnesota but deep layer shear is quite
limited. Some stronger storms have developed this afternoon but
they are short-lived due to lack of organization and stronger
forcing. The chance for showers/storms will move east through the
evening continuing into the rest of northeast Minnesota into parts
of far northern Wisconsin. They should dissipate late evening or
shortly after midnight. Fog will then be possible later tonight as
skies clear and winds go light.

High pressure will move in later tonight along with an upper level
ridge. Saturday will be a dry day under partly to mostly sunny
skies. Winds will become west to southwest and highs will climb
into the upper seventies to lower eighties.

.LONG TERM...(Saturday night through Friday)
Issued at 257 PM CDT Fri Aug 18 2017

The extended forecast is highlighted by above average temperatures
for Sunday, with a bit of a cool-down Monday through Thursday, as
well as a few shots at showers and storms, with possibly the return
of severe weather Sunday night.

Saturday night looks to be dry before a cool front boundary dives
southeastward, along with a mid-level shortwave. Some enhanced 850-
700 mb FGEN and enhanced low-level convergence will provide the lift
along this boundary. The best chances of precipitation with this
cool front will be Sunday morning. Not really expecting much in the
way of precipitation due to the low-level atmospheric moisture
profiles being fairly dry per the 18.12z NAM soundings. Highs Sunday
will range from the upper 70s north to the lower 80s over northwest
Wisconsin.

The best chances for precipitation for the extended forecast period
look to be from Sunday night through Tuesday morning. The
aforementioned cool front boundary stalls along our southern
counties Sunday night, and ultimately lingers over this area. The
baroclinic zone along the boundary remains stationary through
Tuesday morning before finally exiting the region. Consensus blend
POPs have low to some low-end moderate chances of precipitation.
With 925 mb temperatures in the upper teens and lower 20 degrees C
over the southern counties, along with a corridor of better
instability, these higher chances of precipitation appear
reasonable. There is a Day 3 convective outlook, with a Marginal
Risk south of a Poplar, MN to Hayward, WI line. The bulk of the
convective activity will remain to our south and west as the
environment is progged to be more unstable compared to over the
Northland. Some of the activity may creep northward into our far
southern counties, but there`s still quite a bit of disagreement
between the synoptic models, so still much uncertainty exists.
Leaned towards the consensus blend POPs for now. Temperatures will
gradually decrease Monday and Tuesday, with highs Monday in the mid
to upper 70s, and highs Tuesday in the lower 70s. Sky cover will be
the thickest over the southern areas due to this system, but other
portions of the Northland may potentially have an opportunity to
view some of the eclipse during the early afternoon, if some brief
clearing develops.

There may be some lingering small chances of showers and storms
Tuesday afternoon, but the trend in precipitation chances should
generally be downward as high pressure makes its way into the
region, which should set up for a drier stretch of weather Wednesday
through Friday. Temperatures remain slightly below seasonal
averages, with highs in the lower to mid 70s. There could be some
pretty cool nights during this period, as lows may drop into the
lower to mid 40s in some spots across our north, especially Thursday
morning.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1235 PM CDT Fri Aug 18 2017

VFR conditions to continue for this afternoon through the evening
over all of the Northland TAF sites. High-level cirrus, with
possibly some lower cumulus clouds, should continue through the
afternoon as modest showers and storms have formed to the south
and west this morning/afternoon. A mid-level shortwave will
support at least chances of showers and thunderstorms, from KBRD
northeastward towards KINL and over the Iron Range of Minnesota.
The high-resolution models differ on the areal coverage of this
activity, so confidence is a bit low on impacts to TAF sites.
Still, continued the mention of VCSH/VCTS across most of the
sites.

A ridge of high pressure then moves into the region tonight,
leading to clearing skies over the Northland. This, coupled with
light winds, will lead to the development of MVFR/IFR fog
for all of the TAF sites, except for KDLH.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  55  80  60  80 /  30   0  20  20
INL  50  81  60  77 /  10   0  30  10
BRD  54  81  60  80 /  30   0  30  20
HYR  53  80  58  82 /  20   0  10  30
ASX  57  83  61  84 /  20   0  10  30

&&

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

$$

SHORT TERM...Melde
LONG TERM...JTS
AVIATION...JTS



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