Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 241131
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
631 AM CDT Fri Mar 24 2017

.SHORT TERM...(Today through Saturday)
Issued at 412 AM CDT Fri Mar 24 2017

Freezing rain, drizzle, sleet, rain and even thunder have been
observed in the forecast area overnight, supporting the earlier
opinion of a difficult forecast. This morning temperatures for
areas generally south of a line through Leech Lake and the Twin
Ports, with warmer temperatures also extending along the North
Shore close to the lake, and all of northwest Wisconsin. The only
accumulating precipitation is generally south of a line from
Ironwood through Hayward, where temperatures are in the mid 30s.
Some drizzle is happening, but this should be producing little if
any icing. Icing from overnight is still probably on the ground or
elevated surfaces, but no more is being generated. Thus, I have
canceled or allowed the winter weather advisories to expire this
morning.

The synoptic set up this morning shows a strong surface low over
southeast Colorado, with a warm front extending up into Nebraska
and Iowa, with a trough extending up across northern Wisconsin. A
very weak cold front/wind shift extends from another strong low
over James Bay southwest across Ontario to drape across North
Dakota. Today the inverted trough over the forecast area is going
to shift only slowly to the southeast, and should serve as the
focus for continued precipitation chances over portions of
northwest Wisconsin, as it is also associated with a tight
baroclinic zone at 850mb. Clouds should be slow to clear out of
the remainder of the forecast area, and expect drizzle and fog to
continue this morning as well. In fact, with northeast winds
developing over Lake Superior, the Twin Ports will likely be
socked in with clouds much of the upcoming 24-36 hours. Highs
today to rise into the upper 30s to upper 40s even with the north
winds beginning to develop. Tonight the clearing should allow mins
to fall into the 20s. By Saturday, wind off of Lake Superior is
going to give us a fairly typical spring temperature pattern, with
highs near the lake only in the 30s, with low to mid 40s
elsewhere.

.LONG TERM...(Saturday night through Thursday)
Issued at 412 AM CDT Fri Mar 24 2017

Upper level and surface ridging covers much of the forecast area
Saturday evening. A piece of upper level energy will rotate from
east to west around a vertically stacked system drifting through the
Central Plains. This will bring a small chance of a mix of rain and
freezing rain to a portion of northwest Wisconsin, mainly east of
Highway 63. This system will meander into the eastern Great Lakes by
12Z Monday. Additional pieces of energy will rotate across primarily
northwest Wisconsin through this period. This will result in periods
of mixed precipitation from rain, to freezing rain, to a rain and
snow mix, with just snow over the Arrowhead. This mixed
precipitation will occur primarily at night. During the day, thermal
profiles will warm enough so that just rain will occur. No
precipitation elsewhere during this time. An upper level long wave
trof will move over the forecast area on Monday with more
possibilities for light rain in northwest Wisconsin. This is where
the best source of moisture will be found for the trof to work with.
The trof departs Monday night which is replaced by upper level and
surface ridging. The ridging prevails through Tuesday night. On
Wednesday, model differences begin to reveal themselves. The ECMWF
and GFS hang onto the ridging, while the GEM has a negatively tilted
upper wave affecting the area, with its associated surface low
moving through south central Canada. Used a blend which gives a nod
to the GEM and places pops over the western two thirds of the
region. A rain/snow mix is expected in the morning before changing
to all rain by mid morning and through the afternoon. Another
vertically stacked system will travel across the Southern Plains
Wednesday night and Thursday. Model differences continues with the
GEM moving the aforementioned surface low across the forecast area,
while the ECMWF/GFS have ridging nearby. Maintained the blended
approach to settle the differences. Temps will be running above
normal.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 631 AM CDT Fri Mar 24 2017

Widespread IFR/low end MVFR cigs and vsbys with fog as the
terminals are between a surface trof over northwest Wisconsin, and
a cold front near INL at the start of the forecast. Some patches
of LIFR where also nearby. The trof and cold front are progged to
move through the area today. This will bring a gradual improvement
in cigs and vsbys into the high end of the MVFR range, then VFR by
late afternoon. There is a potential for a return to IFR cigs
toward the end of the forecast when the wind diminishes and a
northeast wind aids in the development of the low clouds.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  42  26  36  27 /  10  10  10  20
INL  40  24  43  25 /  10   0   0   0
BRD  47  28  46  29 /   0   0   0  20
HYR  45  28  45  30 /  30   0  10  30
ASX  43  28  40  29 /  10  10  10  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 10 PM this evening to 4 AM CDT Sunday
     for LSZ121-140>148.

&&

$$

SHORT TERM...LE
LONG TERM...GSF
AVIATION...GSF



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