Area Forecast Discussion
Issued by NWS Duluth, MN

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889
FXUS63 KDLH 181755
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1155 AM CST Wed Jan 18 2017

.UPDATE...
Issued at 1155 AM CST Wed Jan 18 2017

Updated for the new 18Z Aviation Discussion below.



&&

.SHORT TERM...(Today through Thursday)
Issued at 305 AM CST Wed Jan 18 2017

One last mostly sunny and mild day today before we start to pay for
the warmth with a prolonged period of cloudiness and light
precipitation.

On the synoptic scale a broad mid-level longwave ridge is dominant
over the northern Plains and southern Canada with an upper low
lurking over the southern Rockies. Today into tomorrow a ridge and
resulting surface high builds across the southeast, leading to the
upper low gradually lifting northeast towards the upper Mississippi
River Valley. Southerly flow ahead of the upper low at low to mid
levels will lead to increasing low level moisture, resulting in
light rain/drizzle developing within the broad area of weak large-
scale lift that develops over the mid/upper Mississippi River
Valley. While the best lift will be further south where better mid-
level PVA develops per good model consensus, some areas of drizzle
will be possible across parts of east-central Minnesota into
northwest Wisconsin come Thursday afternoon.

Highs in the mid to upper 30s today, with some locations likely
reaching into the low 40s like Hayward, Moose Lake, and a few other
spots did yesterday. (850mb temps approaching +10C aloft might
suggest even warmer highs, but a consistent inversion will mean most
locations will only mix up to around 925mb at best.) Lows tonight in
the low to mid 20s, which is warmer than our usual high temperature
near 19. And again slightly warmer ahead of the upper low on
Thursday with highs in the upper 30s to low 40s.

While at this point it doesn`t look like any records will be broken,
temperatures may approach record highs today Jan 18 (DLH record 44,
forecast 36; INL record 39, forecast 35) and especially tomorrow Jan
19 (DLH record 44, forecast 38; INL record 40, forecast 38).

.LONG TERM...(Thursday night through Tuesday)
Issued at 305 AM CST Wed Jan 18 2017

A closed low within a negatively tilted trof will lift northward
from the Central Plains Thursday night and through the forecast area
Friday night. The closed low is absorbed into the wave during this
trip. A southerly flow of moisture will inject into the system as it
passes. There are differences in the models thermal profiles which
has an impact on the precipitation type. Used a model blend for the
thermal profiles to discern precipitation types. There are also
disagreements in the amount of QPF generated. The GFS has less than
the ECMWF and GEM. The SREF favors the GFS and will lean its way. A
second cut off upper low will drift northward from the Central
Plains through Minnesota Saturday through Sunday. The models are
fairly similar with the handling of this system, except the QPF
where the ECMWF and GEM has more than the GFS. Used a blend here as
well to account for the differences. Thermal profiles continue to
suggest a mix of ptypes. However, forecast soundings from the GFS
and the ECMWF no longer support freezing rain or sleet and have
removed. Sunday night and Monday finds the next upper long wave trof
rotating through the region. The models are in general agreement
with the mass fields and the thermal profiles. Will continue to see
a mixed ptype of rain and or snow. There will be some periods of
quiet weather for much of the forecast area Monday night and
Tuesday. Where precipitation is expected to linger is over the
Arrowhead and the eastern Wisconsin zones as an upper trof affects
these areas. Will also see precipitation working back into the
Brainerd Lakes area as early as Tuesday afternoon ahead of the next
closed low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1155 AM CST Wed Jan 18 2017

The widespread clear skies and light winds across northeast
Minnesota and northwest Wisconsin will likely continue through at
least most of tonight. There is a low chance of fog late tonight.
The biggest concern is the threat of IFR/MVFR stratus moving into
the Northland from the south late tonight and Thursday morning
when a surge of moisture begins to move into the region. Not
confident yet that this stratus will reach Northland terminals by
late morning, but the best chances of this occurring by the
afternoon will be at KHYR and KBRD, followed by KDLH and KHIB. The
NAM and GFS show high humidity around 950 and 925 hpa spreading
into the region late tonight and in the morning, but have concerns
that the stratus might not develop until even deeper moisture
arrives Thursday afternoon and evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  36  24  38  31 /   0   0  10  20
INL  35  19  38  28 /   0   0   0  10
BRD  38  21  39  31 /   0   0  10  20
HYR  38  24  40  31 /   0  10  10  20
ASX  40  26  42  32 /   0   0  10  20

&&

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

$$

UPDATE...Grochocinski
SHORT TERM...JJM
LONG TERM...GSF
AVIATION...Grochocinski



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