Area Forecast Discussion
Issued by NWS Duluth, MN

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436
FXUS63 KDLH 240511
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1211 AM CDT Tue Apr 24 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 341 PM CDT Mon Apr 23 2018

A cold front was heading through northeast MN late this
afternoon. At 3 pm the front was generally from Ely to over Lake
Winnibigoshish. The front kicked up some gusty northwest winds for
a couple hours. No precipitation is expected with the front
although some cumulus did develop along and ahead of it. It will
be cooler tomorrow for a couple reasons. A vigorous upper level
vorticity maxima will move across the the region tomorrow. While
low level moisture is lacking, there will be enough to create
clouds. The cloud will hold down temperature rises. In addition,
cold air behind the front will temper temperature rises. 8h
temperatures in the single digits above zero will fall into the
single digits below zero on Tuesday.

.LONG TERM...(Tuesday night through Sunday)
Issued at 254 AM CDT Mon Apr 23 2018

Quiet throughout the extended with precipitation chances returning
Thursday before mild temperatures return this weekend.

A ridge will be situated across central portions of Canada Tuesday
evening, while ahead of it a trough will be located across the
Western Great Lakes. The trough will dig into the Central and
Eastern Great Lakes through Wednesday, while the ridge builds into
the Upper Mississippi River Valley. 850 hPa flow will gradually
shift from a northerly direction overnight to westerly flow by the
afternoon. This will result in a good setup for strong radiational
cooling due to clear skies, light winds and cold air advecting into
the region. Lowered overnight low temperatures a few more degrees
compared to the previous forecast package. Low temperatures range
from the low 20s across the Minnesota Arrowhead to the mid to upper
20s elsewhere. Temperatures will quickly rebound during the day on
Wednesday as warm westerly 0 to 5 degree Celsius 850 hPa air advects
into the region. High temperatures range from the  mid to upper 40s
immediately adjacent to the Lake Superior Shoreline, to the mid 60s
across the International Falls area. Expect it to be quite dry
across the Northland with relative humidity values bottoming out in
the 20 to 35 percent range across much of the region. A bit
concerned that wind speeds/gusts may be higher than currently
thinking, which could put portions of north-central Minnesota near
critical fire weather thresholds.

The ridge will slide into the Central Great Lakes on Thursday, while
another trough digs southeastward from central Canada into the Upper
Mississippi River Valley. At the surface a cold front will slide
across the Dakotas into and through much of the Western Great Lakes.
There are differences between the GFS/GEM and ECMWF guidance on the
strength of trough moving which impacts the strength of the cold
front. The GFS brings the most widespread precipitation to the
region, as the forcing aloft is the strongest. Suspect that this is
overdone as was the trend with this next incoming system (for
tomorrow). Think that the final solution is somewhere between the
ECWMF (driest and weakest wave) and the GEM (drier than the GFS, but
stronger wave than the ECMWF). Would like to see how things trend as
the week progresses to get a better handle on the front moving
through. Regardless of model, cooler temperatures are expected as
flow aloft becomes northwesterly and advects cold air into the
region. Expect high temperatures to be in the 50s on Thursday. A
compact shortwave will dig in behind the trough moving into the
Central Great Lakes late Thursday night into early Friday. This may
provide enough lift to generate some rain/snow showers across the
Minnesota Arrowhead, but confidence is quite low as guidance is all
over the place.

High pressure will build back in late in the week through much of
the weekend as a ridge slides from the Western US into the Central
and Northern Plains. Expect a warm up as flow becomes
southerly/southwesterly aloft through the weekend. Readings by
Sunday range from the mid 50s along the Lake Superior Shoreline to
near 70 degrees across north central Minnesota.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1211 AM CDT Tue Apr 24 2018

A cold front will make slow progress through the Northland tonight
with little sensible weather occurring with it. An upper level trough
will move southeast into the Northland late tonight and move through
on Tuesday. VFR ceilings will be on the increase ahead of this
trough and the chance for any rain is low. The gradient will tighten
late tonight into Tuesday and northerly winds are expected. The wind
will diminish quickly Tuesday evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  40  53  29  56 /  10  10   0   0
INL  36  49  25  61 /   0   0   0   0
BRD  43  57  29  60 /  10  10   0   0
HYR  36  53  27  56 /  10  10   0   0
ASX  36  52  27  54 /  10  10   0   0

&&

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

$$

SHORT TERM...CLC
LONG TERM...GSF
AVIATION...Melde



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