Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 232255
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
555 PM CDT Thu Mar 23 2017

.UPDATE...
Issued at 556 PM CDT Thu Mar 23 2017

Forecast updated to reflect current observations and guidance.
Fine-tuned overnight temperatures, dew points, QPF, and
weather/snow/ice. In general only minor adjustments were made,
with ice amounts remaining about the same for the higher terrain
of the MN Arrowhead (and slightly increased NE of Duluth) while
ice amounts in NW Wisconsin have been reduced in most areas given
the wet bulb temps above freezing right now. Thunder probabilities
were also adjusted as a period of isolated storms is expected this
evening...impacting areas as far north as Walker.

With lower confidence in NW Wisconsin, Advisory may be trimmed
back in a later update. Will continue to monitor trends as the sun
goes down and precipitation develops. Advisory for NE MN looks
good for now. The threat for freezing rain is a limited one, but
given the extreme impacts it can have we have leaned towards more
of a worst-case scenario with regards to ice amounts. Would not
be surprised to hear of ice accumulation over a tenth of an inch
in an isolated spot or two, but most locations will see little ice
and little impacts given road surface temps around 35-36 right
now.

&&

.SHORT TERM...(This evening through Friday)
Issued at 318 PM CDT Thu Mar 23 2017

Nature is providing us a challenging forecast today, with the
potential for a wintry mixture of multiple precipitation types and
thunder. The focus remains on the freezing rain threat. It still
appears there could be anywhere from a very light glazing of ice
to up to a tenth of an inch of ice over the Arrowhead, Duluth
area, Iron Range, and parts of the eastern forecast area in
northwest Wisconsin. The greater threat is over northeast
Minnesota. The current Winter Weather Advisories seem sufficient,
but did consider expanding the advisory farther west into north
central Minnesota. However, not as confident about the potential
for freezing rain that far west.

An upper-level ridge will continue moving east through the western
Great Lakes region this afternoon and evening. Southerly flow
across the Upper Midwest brought a surge of moisture northward
into the Northland last night and today, and even more moisture
will move into the region late this afternoon and this evening.
Light rain will become more widespread across the Northland this
evening. Subtle shortwaves might lift into the Northland this
evening, and help develop elevated-based thunderstorms off the
saturated stronger flow well aloft. This thunder threat is mainly
for the southern two-thirds of the forecast area.

The cloud cover today prevented much heating, and the relatively
cool temperatures in the 30s will cool this evening. This opens
the threat to freezing rain and other wintry precipitation
tonight. The coldest surface temperatures will likely be across
the Minnesota Arrowhead, Duluth area, and Iron Range, where
temperatures will drop to near or a bit below freezing. The rain
will likely transition to freezing rain over those areas and
result in some icing overnight, possibly as much as a tenth of an
inch of ice. There could also be a period of light snow and sleet
over this area, but there will likely be little if any
accumulation. There is a threat of freezing rain in parts of
northwest Wisconsin, too. It is mainly for Iron, Price, and
Ashland Counties, but also for areas east of Hayward and over the
Bayfield Peninsula. This threat is more nebulous because
temperatures will likely take longer to reach the freezing mark,
as compared to northeast Minnesota. The Winter Weather Advisories
seem sufficient for both areas, though, even though confidence is
not as great for northwest Wisconsin, because even if air
temperatures do not quite get as cold as the freezing mark, road
surfaces may be colder than the air temperature. Other parts of
the Northland will likely maintain light rain as air temperatures
remain a bit above freezing.

The precipitation will gradually shift south and east later
tonight into Friday morning as a cool front moves through the
Northland from the northwest to southeast. The precipitation will
transition back to just rain Friday morning with the warming air
temperatures. There will be some scattering of the cloud cover
Friday, primarily over northeast Minnesota as drier air filters
into the region from the north. Rain will continue for some parts
of Wisconsin through the middle of the day, mainly near Price
County and areas to its south and east. Highs should range from
the upper 30s to middle 40s.

.LONG TERM...(Friday night through Thursday)
Issued at 318 PM CDT Thu Mar 23 2017

A cutoff low will rotate from the Central Plains into the Mid
Mississippi River Valley on Saturday, while a ridge nudges its way
into the Northland from James Bay. This will initially bring
chances of a wintry mix across portions of northwest Wisconsin per
the GFS/NAM/ECWMF and CMC. The cutoff will lift northeastward
into the Central Great Lakes late on Saturday and Sunday. This
will gradually spread rain from east to west Saturday through
Sunday. From Saturday evening into early Sunday sounding profiles
show a chance of freezing rain across northwest Wisconsin and
eastern portions of northeast Minnesota. As surface temperatures
warm, expect precipitation to change over to all rain for the rest
of Sunday.

The cutoff will move into the Eastern Great Lakes late on Sunday
and into Monday, while another trough lifts into the Mid
Mississippi River Valley on Monday. There are some model
differences in the strength of the next trough moving in with the
CMC/GFS depicting a stronger wave than the ECMWF. Regardless, it
looks like another round of wintry precipitation will be possible
late Sunday evening into early Monday from eastern portions in
northwest Minnesota through northwest Wisconsin. Precipitation
will change over to all rain across northwest Wisconsin during the
afternoon and potentially snow before things end Monday evening.
After this, high pressure will build in from Tuesday through
Wednesday as a 500 hPa ridge slides from the Northern Plains into
the Central Great Lakes. Precipitation chances return late in the
week as a cutoff low develops across the Central Plains and lifts
northward.

High temperatures on Saturday and Sunday range from the upper 30s
to the mid 40s. Warmer temperatures are expected on Monday
through Thursday with highs ranging from the low 40s to the low
50s. Low temperatures through the weekend will be in the 20s. Low
temperatures from Monday through Thursday range from the mid 20s
to the mid 30s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1257 PM CDT Thu Mar 23 2017

VFR to start at the beginning of the forecast, with a gradual
spread of MVFR ceilings as precipitation moves in. Expect
precipitation to begin around 20-23Z. As precipitation moistens up
the column, ceilings will gradually lower to IFR/LIFR at all
terminals. In addition, visibilities will gradually lower to
MVFR/IFR as heavier rain moves in. There is a chance of
thunderstorms impacting KHYR, KDLH and KBRD around 00Z, but
confidence is low and have left out for now.

Based on the NAM/RAP and HRRR soundings expect a freezing rain
threat at KDLH/KHIB and KHYR. Confidence is low as temperatures
are right on the border of a freezing rain or rain threat at these
locations. Right now the best timing is for between 00Z and 11Z.
After precipitation moves out, expect ceilings to gradually lift
to MVFR as high pressure builds in from the north. KHYR will
remain in IFR ceilings as precipitation still lingers around at
18Z.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  32  42  26  37 /  80  10  10  10
INL  29  40  23  42 /  60   0   0   0
BRD  33  47  28  45 /  80  10  10   0
HYR  34  45  28  44 /  80  40  10  10
ASX  33  43  28  40 /  80  30  10  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 10 PM this evening to 9 AM CDT
     Friday for WIZ002>004-008-009.

MN...Winter Weather Advisory until 7 AM CDT Friday for MNZ011-012-
     019>021-037.

LS...None.
&&

$$

UPDATE...JJM
SHORT TERM...Grochocinski
LONG TERM...WL
AVIATION...WL


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