Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 161741 AAB
AFDDLH

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1241 PM CDT Mon Apr 16 2018

.UPDATE...
Issued at 1241 PM CDT Mon Apr 16 2018

Update for new 18Z Aviation Discussion below.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 356 AM CDT Mon Apr 16 2018

A broad area of synoptic light to moderate snow is diminishing
across the Northland this morning, which should only continue this
downward trend through the morning hours. The surface low that
brought the heavy snow yesterday and earlier this morning will
continue to march eastward over the Appalachian Mountains today.
However, this area of low pressure is progged to retrograde towards
the eastern Great Lakes later today, keeping the Great Lakes region
underneath the cyclonic flow of this system. While current radar
imagery shows the synoptic snow slowly diminishing, some lake effect
snow bands have developed mainly over Douglas and Bayfield counties
in northwest Wisconsin. Winds will continue to be from the northerly
direction today due to the cyclonic flow overhead. This, coupled
with 850-surface delta-T values around 15 degrees, will lead to
continued lake effect snow, albeit at a slower rate since we lose
some of the deeper saturation that we had yesterday. Due to the on-
going lake effect and synoptic snow, we will continue our headlines
as is, with the plan to have them expire at 7 AM this morning. With
that said, we may have to either continue the Winter Storm Warning,
or issue a Winter Weather Advisory, for Iron county as some heavier
lake effect snow is expected along the higher elevations of the
Gogebic Range. New snowfall totals through this afternoon should
range between 1 to 4 inches over the Lake Superior snowbelt region.
While the low pressure system churns over the Great Lakes, an upper-
level ridge will build into the region from the west. Clouds will
gradually clear up from west to east later this afternoon through
the overnight hours as this ridge builds in. With the freshly fallen
snow, and overcast skies expected across much of the Northland,
decided to decrease today`s high temperatures slightly. Today`s
highs should range from the upper 20s over the east to the upper 30s
over north-central Minnesota where the sun should peek out later
this afternoon.

Chances of lake effect snow should continue overnight and into
Tuesday morning as the 1000-850 mb winds remain from a northerly
direction. However, NAM soundings indicate a loss of dendrites over
KIWD, as well as some drier air filtering into the region, so
chances of lake effect snow will diminish Tuesday afternoon. More
abundant sunshine is expected for Tuesday, so high temperatures will
rise to the lower to middle 30s east to the lower to middle 40s west.

.LONG TERM...(Tuesday night through Sunday)
Issued at 356 AM CDT Mon Apr 16 2018

Once the ongoing winter/spring storm moves out of the area, the next
weather system of concern is Wednesday and Wednesday night.  As the
upper low with the current system moves slowly off to the east,
another upper low moves across the Rockies, ejecting a fairly strong
shortwave out over the central plains Tuesday night through
Wednesday night.  The track of this storm takes the bulk of the
resulting precipitation across Southern Minnesota and the southern
half of Wisconsin. However, several of the models spread some
stratus and light precipitation into the forecast area.
Unfortunately, this has enough warm air aloft and with the surface
cold air in place, we have a threat of freezing drizzle/rain
Wednesday morning.  Do not think we are looking at anything
significant for ice accumulations, but it is a concern that we will
have to monitor carefully.  Later in the day we are looking more at
rain/drizzle as temperatures warm, then back to snow in the evening.

Beginning Thursday the weather forecast goes relatively quiet for
the forecast area.  The upper level flow remains blocky with upper
lows over the northeast CONUS and another over the 4 Corners region
Thursday.  The western upper low slides east across the southern
Plains, leaving us out of the main storm track through the
upcoming weekend. Temperatures gradually rise to near to just
above normal for the weekend. Expect some melting of snow to
occur, perhaps we can get things looking more spring like around
here, though it would probably be best for the rivers if this
melted more slowly.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1241 PM CDT Mon Apr 16 2018

The lingering affects of the weekend storm system will continue
across the terminals today. Stratus is gradually eroding over our
western forecast area, including INL and BRD. GOES-16 visible
satellite imagery shows surface features (lakes, rivers) visible
through the stratus even though observations feature OVC or BKN
skies. Lake- effect snow will continue to affect fields in
northwest Wisconsin this afternoon into this evening, including
HYR. Farther west, ceilings will gradually lift to VFR with light
snow showers continuing. Additional cloud cover may rotate over
INL later this afternoon and linger overnight. MVFR ceilings
should return to HYR on Tuesday morning as lake-effect processes
continue.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  33  19  37  24 /  70  10  10  10
INL  36  20  43  27 /  50   0   0  10
BRD  38  19  41  26 /  20   0   0  10
HYR  32  21  38  23 /  70  20   0  10
ASX  32  25  35  24 /  80  70  20  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 1 AM CDT Tuesday for WIZ004.

MN...None.
LS...Small Craft Advisory until 10 AM CDT Tuesday for LSZ121-140>148.

&&

$$

UPDATE...Huyck
SHORT TERM...JTS
LONG TERM...LE
AVIATION...Huyck



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