Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 292111
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
411 PM CDT Sat Apr 29 2017

.SHORT TERM...(This evening through Sunday)
Issued at 311 PM CDT Sat Apr 29 2017

Fairly quiet conditions through the long term with the initial
wave of precipitation from the pending winter storm arriving in
the form of rain showers on Sunday.

High pressure ridging will loiter over the Northland this evening
and Sunday morning with thin cirrus and light winds expected
until late tonight. The initial wave of showers is forecast to
nose into our southern zones by sunrise, with a better chance of
rain later in the day. With clouds slow to expand northward
tonight, lowered minimum temperatures in the Arrowhead into the
middle to low 20s, a bit cooler than consensus guidance. Also
nudged RH values drier Sunday in north-central Minnesota, where
clouds will remain thin and efficient mixing is likely once again.

.LONG TERM...(Sunday night through Saturday)
Issued at 311 PM CDT Sat Apr 29 2017

A late winter storm will continue to take aim on the Northland
Sunday night, as surface low pressure reaches southwest Iowa by
00Z Monday. Rain will gradually change to snow as it moves
northward across our CWA. There are still so many questions with
regard to placement and snowfall totals, but there is enough
confidence at this point to issue a Winter Storm Watch for much of
northeast Minnesota. The Winter Storm Watch will begin at 10 PM
Sunday night, and continue to 10 PM Monday night, although snow
will likely linger beyond this time for much of the area. The low
pressure system is expected to transition to a double-barrel low
by 12Z Monday, as the upper level low lifts into the western Great
Lakes. By 00Z Tuesday, the low should reach the Upper Peninsula
of Michigan. Forecast soundings, as well as SREF and GEFS plumes
indicate the potential for locally heavy snow across much of
northeast Minnesota, especially areas west of Duluth and Grand
Marais, with WPC continuing to indicate the potential for 6 or
more inches of snow across portions of the watch area. Think when
all is said and done, snowfall amounts will be quite variable,
given the potential for mixed precipitation, and the potential for
very heavy snowfall rates due to TROWAL feature/cold conveyor
belt mesoscale banding. The GEFS and SREF plumes have actually
increased over the past run, and do indicate some 10 inch mean
snowfall amounts across the watch area. Further south and east of
the watch area, we could see some icing. Did not have enough
confidence at this point to issue a watch for other portions of
the CWA, but will have to watch carefully for the potential
elsewhere. Have coordinated extensively with the Minneapolis/
Chanhassen office and the eastern North Dakota/Grand Forks office
regarding snow ratios and expected snowfall totals. The result is
consensus snowfall amounts of around 6 inches or better for the
duration of the watch. The surface low will move off to the north
and east for the remainder of the week, although another weak
shortwave will bring a small chance of precipitation from
Wednesday into Wednesday night. A massive upper level ridge will
bring much warmer temperatures to the Northland for the latter
half of the week and into the weekend. Highs will range from the
30s across the area on Monday, to the 60s on Friday and Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 112 PM CDT Sat Apr 29 2017

High pressure will gradually lose its grip on the Northland
overnight and into Sunday, although VFR conditions are expected to
continue throughout the period. Some mid and high clouds will move
in late tonight and Sunday morning, especially in the south.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  30  41  32  36 /   0  50  90  80
INL  28  53  34  43 /   0  10  50  70
BRD  33  48  34  41 /   0  60  90  80
HYR  30  45  35  42 /  10  70  80  80
ASX  29  40  34  40 /   0  60  90  80

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Storm Watch from Sunday evening through Monday evening
     for MNZ011-012-018-019-025-026-033>036.

LS...Small Craft Advisory from 4 AM Sunday to 4 PM CDT Monday for
     LSZ121-140>148.

&&

$$

SHORT TERM...Huyck
LONG TERM...DAP
AVIATION...DAP



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