Area Forecast Discussion
Issued by NWS Duluth, MN
FXUS63 KDLH 021041 CCB
Area Forecast Discussion...CORRECTED
National Weather Service Duluth MN
441 AM CST Fri Dec 2 2016
.SHORT TERM...(Today through Saturday)
Issued at 407 AM CST Fri Dec 2 2016
The Northland remained between low pressure well off to the east and
weak high pressure over the Northern Plains. Plenty of low level
moisture remained under the inversion and will lead to mostly cloudy
skies today. There is a chance for a peek or two at the sun in
spots, but the majority of the region will remain mostly cloudy.
It`s possible some flurries or light freezing drizzle could occur,
but observations have not reported any precipitation so far other
than over portions of northwest Wisconsin. There has been some
lake effect precipitation in the snow belt and KPBH briefly
reported some light precipitation. We will continue a chance for
snow showers or patchy freezing drizzle over portions of the snow
belt, but we do not expect much accumulation. A spotter in Gile at
105 am reported only 0.6 inches of snow since 1030 am Thursday
bringing the total to 2.4 inches. The visibility at KIWD and
webcams suggest little additional snow has fallen since that
report. Low level flow is forecast to back through the day and
become more westerly by this evening. Expect highs today from the
mid twenties to lower thirties.
Weak ridging will move into the Northland tonight and we expect the
clouds to stick around through the night. There could again be some
light freezing drizzle or flurries in spots but coverage looks to
be too limited to include at this time other than over a small portion
of northern Wisconsin. Lows tonight will range from 20 to 25...but
there could be colder pockets should any brief clearing occur.
The ridge will continue east on Saturday into Wisconsin. It should
remain mostly cloudy although there is a better chance for a few
peeks at the sun. Highs will range from the mid twenties to
.LONG TERM...(Saturday night through Thursday)
Issued at 407 AM CST Fri Dec 2 2016
Main concerns during the long term remain precipitation chances and
types with a late weekend system, the potential for several rounds
of precipitation Monday through Thursday, and cooler temperatures.
Not much change to the going forecast this morning due to continued
low confidence in sensible weather details. A trough of low pressure
and area of surface low pressure will move across the Dakotas
Saturday night and Sunday. Southwesterly flow ahead of the trough
will advect a combination of Gulf and Pacific moisture into the
Northland. The long trajectories and precipitation forecast to occur
south of the area will limit the precip potential locally.
Maintained a chance of rain and snow showers Saturday night through
Sunday evening, with precip spreading from west to east with time.
Unseasonably mild conditions across the Plains and Upper Midwest,
and the lack of a robust reservoir of cold air to tap, continues to
play merry hob with max and min temps and resultant precip types.
Seems cold enough for all snow Saturday night with a potential for
rain advancing up the I-35 corridor during the day. By mid-
afternoon, the possibility of a rain/snow mix will span from the
Brainerd Lakes along and south of MN Highway 210 to the Twin Ports
and then across most of northwest Wisconsin. Precipitation amounts
with this disturbance appear fairly low, generally less than 0.15
inches. There should be a heat and moisture contribution from
western Lake Superior, which would enhance snow/rainfall amounts
along the North Shore due to southerly winds ahead of the low. Snow
totals less than 2 inches are expected with this system. There is
also a potential for freezing drizzle Saturday night, however this
seems unlikely as of this morning and have kept precip types simple.
A weak ridge of high pressure will slide east across the area Sunday
night and Monday morning bringing a brief reprieve from
precipitation. Another stout thermal inversion is likely with this
weak ridge, which would keep skies mainly cloudy with isolated snow
showers or pockets of freezing drizzle possible.
The next potential troublemaker is forecast to move into the
Northern Plains and Upper Midwest Monday afternoon and Monday night.
Deterministic models and GEFS members are clustered around a similar
track with the surface and low-level trough. Kinematic details
expose more variety in potential outcomes with the GFS faster and
stronger and the CMC slower and farther south. ECMWF is in the
middle of the pack by Monday evening. The GFS solution would bring a
quick-hitting burst of rain and snow showers to the Northland Monday
afternoon through Tuesday afternoon while the ECMWF focuses the
heaviest precipitation over the eastern Dakotas into Manitoba. The
CMC solution would yield the most precipitation for our area with
precip along the warm front Monday night, and wrap around
precipitation hitting my northwest zones Tuesday afternoon and
evening. Given the differences in the details, maintained a
consensus approach for now.
Beyond Tuesday night the differences in deterministic guidance and
ensemble members increase markedly. ECMWF winds up a strong system
and lifts it from the southern Mississippi Valley into the eastern
Great Lakes through Thursday night, with marginal precipitation over
the Northland from a cutoff low over the Canadian Prairies. GFS has
a similar solution but is faster with the evolution and movement of
the surface low and associated shortwave trough. GEFS members are
spread out from southern Manitoba to the eastern Great Lakes. All of
the solutions this morning would yield some precipitation for the
Northland between Wednesday night and Friday. There is still a
possibility the system could actually track farther west than this
morning`s guidance suggests. Should a more westerly track emerge,
precip amounts and intensity would be much higher. For now, am
content to maintain a consensus blend until model consistency
Temperatures will start the period slightly above normal and will
gradually cool through Friday to near to slightly below normal. The
most notable changes in the temperatures will be in the daytime
highs with readings 8 to 12 degrees below normal by Friday.
Overnight lows will remain near to slightly above normal through
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1152 PM CST Thu Dec 1 2016
Widespread MVFR ceilings and VFR visibilities as of issuance time is
expected to continue through the TAF period. Some snow showers with
MVFR visibilities possible, but their timing is uncertain and
have gone with just VCSH with lower ceilings for now.
.PRELIMINARY POINT TEMPS/POPS...
DLH 30 24 29 24 / 10 10 10 30
INL 28 21 28 23 / 10 10 10 30
BRD 30 22 30 27 / 10 10 10 30
HYR 31 24 30 24 / 10 10 10 30
ASX 33 26 32 25 / 10 10 10 20