Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 210530
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1230 AM CDT Thu Sep 21 2017

.SHORT TERM...(This evening through Thursday)
Issued at 255 PM CDT Wed Sep 20 2017

High pressure building behind a cold front is leading to clear skies
today and should result in a sunny and mild day on Thursday. Like
the cold front ahead of it, this area of high pressure will be quick
to build eastward towards eastern Ontario resulting in southerly
flow returning tomorrow. With full sunshine and mixing to around
900mb breezy southeast winds will prevail in the afternoon with the
southerly flow not only resulting in warm air advection but also low
level moisture return; dew points will return to the low/mid 60s by
tomorrow afternoon.

Late this afternoon there is a low probability for a thunderstorm
to develop along the cold front boundary seen on radar/satellite
given around 1000 j/kg MLCAPE ahead of the front. However, there
is only a very narrow corridor of clearing skies ahead of the
front due to the extensive stratus across northeast WI and the
U.P., so the possibility for any storms developing within our CWA
late today seems increasingly low.

Tonight as skies clear out, fog is possible given rainfall last
night into this morning. Best chance for dense fog will be northwest
Wisconsin (mainly east of Ashland to Hayward) where clouds will not
clear until the late afternoon today, but otherwise at least some
shallow ground fog is possible across the rest of the Northland as
winds go near calm for a period of the night. Lows tonight in the
40s to perhaps as cool as the upper 30s across inland portions of
northeast Minnesota such as across parts of the Iron Range and up
the Gunflint Trail.

Sunny and warmer Thursday. Southeast winds 10-15 mph with gusts
around 20-25 mph possible, except in the Twin Ports where a strong
northeast winds off Lake Superior may result in a more easterly wind
direction. Highs in the 70s, except for the mid 60s along the north
shore due to winds off Lake Superior. While guidance was a bit
warmer in previous days, model trends have fallen a bit cooler.
Still, temperatures will be above normal with highs as warm as the
upper 70s across the I-35 corridor in Pine county east across
northwest Wisconsin away from Lake Superior. Increasing clouds from
south to north late in the afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 255 PM CDT Wed Sep 20 2017

The Northland will enter a extended period of potentially wet and
stormy weather the latter half of this week through early next week.
An area of high pressure over the eastern US and eastern Canada will
blocked from shifting east late this week and over the weekend
because of drifting tropical storm/depression Jose. This will leave
the Northland in a prolonged period of warm and relatively humid
south to southwesterly flow. Precipitable water values will be about
1.5 to maybe up to 2 inches, quite high for this time of the year.
Multiple shortwaves could lift through the region, providing forcing
to trigger showers and thunderstorms. Also, a quasi-stationary front
will slowly shift eastward through the Northland this weekend
through Tuesday, providing another mechanism for precipitation. Days
of showers and storms, tapping into this deep moisture, could result
in very saturated soils and some flooding. It is too soon to narrow
down the flooding risk to any particular area, but we will be
keeping on eye on the flooding potential. Much of it will depend on
where and how much rain falls from thunderstorms with reach round.

Temperatures late this week will be very warm, 15 to 20 degrees
above seasonal normal on Friday, and about 10 to 15 degrees above
normal for much of the forecast area Saturday. Highs on Friday are
forecast for the middle 70s to middle 80s, with the warmest weather
in northwest Wisconsin and areas of nearby Minnesota. Temperatures
will return to near seasonal normal early next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1229 AM CDT Thu Sep 21 2017

High pressure will remain in control of the Northland`s weather
overnight and into Thursday, although an area of low pressure and
frontal boundary will approach the region, and start to impact our
weather by Thursday night. Gusty southerly winds ahead of the
system will develop on Thursday. VFR conditions are expected
through Thursday, with some local IFR/MVFR CIG`s and VSBY`s
overnight in fog, and again on Thursday evening. Scattered
showers and thunderstorms are expected to develop Thursday
evening, but especially during the overnight hours Thursday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  46  69  59  78 /   0   0  50  30
INL  44  73  58  74 /   0   0  30  40
BRD  47  75  65  85 /   0  10  50  20
HYR  44  77  66  86 /   0  10  30  20
ASX  44  75  62  87 /   0   0  40  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 10 AM this morning to 10 PM CDT this
     evening for LSZ121-146>148.

     Small Craft Advisory from 10 AM this morning to 5 AM CDT Friday
     for LSZ140>145.

&&

$$

SHORT TERM...JJM
LONG TERM...Grochocinski
AVIATION...Melde/DAP


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