Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 162034
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
334 PM CDT Sat Sep 16 2017

.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 18Z TAFS through 18Z Sunday afternoon)
Issued at 1243 PM CDT Sat Sep 16 2017

MVFR to LIFR conditions observed across the Northland TAF
terminals, except for KHYR, as we remain underneath sfc low
pressure. A cold front boundary is slowly moving through the
Northland this afternoon, which should spark some showers and
thunderstorms later this afternoon and evening. There is some
uncertainty regarding the areal coverage of this activity as there
is a good bit of disagreement between the HRRR/NAMNest/NMM/ARW
guidance, so used some VCSH/VCTS where applicable. Some drier,
but cooler, air will move in once the cold front passes overnight.
MVFR fog is expected to develop as surface dew point depressions
upstream behind the front are rather small, so fog potential does
exist. The highest confidence of vsby reductions remains over
KINL, KHIB, and KDLH.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  50  60  45  62 /  80   0   0  20
INL  45  56  40  65 /  30  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...Beach Hazards Statement until 8 PM CDT this evening for WIZ001.

MN...Beach Hazards Statement until 8 PM CDT this evening for MNZ037.

LS...Small Craft Advisory from 1 AM to 7 PM CDT Sunday for LSZ121-
     143>148.

     Small Craft Advisory until 4 PM CDT this afternoon for
     LSZ141>143.

     Small Craft Advisory from 4 AM to 7 PM CDT Sunday for LSZ140>142.

&&

$$

SHORT TERM...Stewart
LONG TERM...JTS
AVIATION...JTS



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