Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 191739
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1239 PM CDT FRI AUG 19 2016

.SHORT TERM...(Today through Saturday)
Issued at 356 AM CDT Fri Aug 19 2016

Some changes made to this forecast as guidance ever so slightly
trends towards the outlier NAM solution for this weekend, which
has repeatedly depicted rapid intense cyclogenesis with a surface
low much further west than other guidance resulting in more
rainfall across the Northland. While a high amount of skepticism
remains with regards to the NAM, these changes have resulted in
increased precipitation amounts on Saturday. Otherwise forecast
remains on track for today/tonight period with showers possible
along the frontal zone across east-central Minnesota and
northwest Wisconsin today, with a few thunderstorms possible given
the elevated instability in place. As drier air works its way in
from the northwest behind the front skies will be on a clearing
trend across north-central Minnesota, with clear skies already
evident on infrared satellite in northwest Koochiching county as
of 3:00am this morning. With cooler air advecting in aloft behind
the front, afternoon cu are anticipated which will result in
partly sunny skies over parts of northeast Minnesota this morning,
cloudy elsewhere in east-central MN and NW Wisconsin. Highs in the
low to mid 70s with dew points gradually falling behind the front.
The Twin Ports will be right on border for precipitation chances,
with a few light rain showers possible through the course of the
day. Tonight increasing clouds with precipitation chances
increasing towards Saturday morning as a low pressure deepens
across the mid- Mississippi valley tracking northeastward towards
the Upper Peninsula by Saturday evening resulting in widespread
rainfall with a few embedded thunderstorms possible. Rainfall
amounts Saturday are expected to be around a half to one inch
across the north shore, south to the I-35 corridor, and east
across all of northwest Wisconsin...but higher amounts are
certainly possible depending upon the intensity and track of the
low.

On the synoptic scale the driver of the outlier NAM appears to stem
from its upper level fields. Up through the 500mb level the NAM
appears to follow model consensus through Sat 12z, but higher up its
jet field depicts a stronger and farther south 100 knot jet streak
across the eastern Dakotas into central and northern MN, thus
kicking off cyclogenesis stronger and earlier than other guidance.
While guidance has trended towards a slightly further west and
stronger surface low, the model consensus remains for the low to be
over the U.P. by Sat 00z while the 00z NAM places it over north-
central Wisconsin. The only guidance with such a far west track is
the 00z Canadian Global and Regional models, which while notable
because this guidance comes from a different center (thus completely
different initialization compared to NCEP suite), this is the first
run both models have exhibited this trend. Compounding evidence that
the 00z NAM is an outlier, the SREF (basically an ensemble of NAMs)
has the mean sfc low in between the model consensus and 00z NAM
solution, and now as the 06z NAM comes in it is MUCH further east
and weaker than the 00z version.

All that said, it sure looks like a dreary day Saturday across
northwest Wisconsin and likely the north shore/Twin Ports. Highs
cooler in the mid to upper 60s with north winds breezy along the
south shore of Lake Superior. An embedded thunderstorm cannot be
ruled out, but given the synoptically-driven nature of the precip
think the 0-500 j/kg MUCAPE will only result in a few rumbles of
thunder at best. Precipitable water values will only be 1.25 to 1.75
tops, which is above average - heavy rain possible at times, but
rainfall rates should not be intense enough to raise any flood
concerns.

.LONG TERM...(Saturday night through Thursday)
Issued at 356 AM CDT Fri Aug 19 2016

The low pressure area will pull out of the region Saturday night
ending most of the precipitation by midnight.  However, there could
be some lingering showers across NW WI Sunday morning before skies
become partly to mostly sunny as high pressure builds into the
region.  High temperatures sunday will be mainly in the 60s.  The
ridge will dominate the weather across the area through Tuesday
with temperatures rising into the 70s on Monday and near 80 on
Tuesday.A warm front will move north through the forecast Tuesday
afternoon through late Tuesday.  there will be a chance for
thunderstorms with the front late Tuesday into Wednesday morning.
A cold front will move through the region Wednesday afternoon
through Thursday morning causing another possibility of showers
and thunderstorms.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1238 PM CDT Fri Aug 19 2016

A boundary across northwest Wisconsin was helping to cause showers
over that area this afternoon. Drier air was working its way south
though and the showers will dissipate over KHYR later this
afternoon. Most areas will remain VFR into tonight, but there will
be some brief IFR or MVFR conditions in the stronger showers.

A stronger low pressure system will move into the region tonight
and impact the area into Saturday. Showers will increase in
coverage later tonight into Saturday and conditions will lower to
IFR or MVFR for most areas.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  73  57  65  49 /  40  70  90  60
INL  74  56  65  46 /   0  30  30  10
BRD  74  58  67  47 /  20  50  70  20
HYR  74  59  66  50 /  70  80  90  60
ASX  74  60  67  53 /  50  80 100  70

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

SHORT TERM...JJM
LONG TERM...Stewart
AVIATION...Melde



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