Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 170540 AAB
AFDDLH

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1240 AM CDT Sun Sep 17 2017

.UPDATE...
Issued at 1240 AM CDT Sun Sep 17 2017

Update for new 06Z Aviation Discussion below.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 333 PM CDT Sat Sep 16 2017

Concern for short term is showers and thunderstorms this evening
through early morning.

current surface analysis indicate are of showers and isolated
thunderstorms moving northeast through Aitkin and Pine Counties.
This is associated a shortwave moving through the region. A cold
front across northern MN is slowly moving south at forecast time.
Ahead of it, temps are in the 70s and dewpoints in the 60s. Behind
it, temps are in the 40s and 50s with dewpoints in the lower to
middle 50s. This front will be the focus of the last round of
showers and thunderstorms this evening. With the movement of the
front the low pressure approaching the area, it looks
thunderstorms will develop along the front as it moves east. SPC
has a narrow area in a marginal risk where the dynamics will be
the strongest.

The precipitation will finally end Sunday morning as an area of
high pressure builds into the region. Skies will be partly sunny
with temperatures cooler than today with highs in the middle 50s
to middle 60s.

.LONG TERM...(Sunday night through Saturday)
Issued at 333 PM CDT Sat Sep 16 2017

The extended forecast period continues to feature a few chances
of showers and thunderstorms through next week, along with
temperatures slightly warmer than seasonal averages.

Sunday night and early Monday morning looks dry as sfc high
pressure lingers over the Northland. Temperatures could decrease
rapidly while conditions are favorable for radiative cooling
before moderating as cloud cover increases ahead of a weak
shortwave trough, which could bring chances of showers Monday.
Models are showing a diffuse precipitation field, so expecting
more isolated or scattered activity. Also, any appreciable
instability appears to be lacking with very little, if any,
MUCAPE. The best chances of showers will be over northwest
Wisconsin as better isentropic upglide will be present there. Mid-
level flow becomes more zonal, bringing dry conditions to the
Northland. Sfc pressure gradient is progged to tighten, especially
over our western counties.

A more potent shortwave trough, and an associated sfc cold front,
will provide support for showers and thunderstorms Wednesday. The
16.12Z GFS is indicating MLCAPE values of 500 to 1000 J/kg at 06Z
Wednesday, with the best instability located over the Brainerd
Lakes. Deep layer shear should strengthen as the low-level jet
intensifies ahead of the front, so some storms could be strong.
Not too confident in severe potential at this point due to the
lack of robust instability, but cannot rule it out entirely.

An upper-level low will develop and continue to churn over the
Alberta/Saskatchewan/Montana region, which will continue to bring
chances of showers and possibly some thunderstorms Friday and
Saturday. These chances of precipitation will also be associated
with a lee cyclone that develops out of Colorado, placing the
region within the warm sector of the low. Temperatures should be
warmer than normal due to southerly flow, with highs in the upper
60s and lower 70s, with perhaps some lower to mid 70s on Friday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1240 AM CDT Sun Sep 17 2017

A cold front will continue to move eastward across the Northland
overnight, eventually ushering in cooler and drier high pressure
as the night wears on. Low clouds, and a few thunderstorms will
continue to linger for a time overnight, but those conditions will
gradually improve from west to east as the night wears on. A mix
of MVFR and IFR CIG`s and VSBY`s should give way to VFR conditions
area-wide on Sunday, as the high pressure builds in. It should
become a bit gusty at times on Sunday, especially during the time
of peak daytime heating.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  50  60  45  62 /  70   0   0  20
INL  45  56  40  65 /  70  10   0  10
BRD  48  61  45  66 /  30   0  10  10
HYR  54  63  43  65 /  70  10   0  40
ASX  55  64  43  66 /  70  10   0  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 7 PM CDT this evening for LSZ121-
     143>148.

     Small Craft Advisory from 4 AM early this morning to 7 PM CDT
     this evening for LSZ140>142.

&&

$$

UPDATE...Huyck
SHORT TERM...Stewart
LONG TERM...JTS
AVIATION...DAP



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