Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 272058
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
358 PM CDT Thu Apr 27 2017

.SHORT TERM...(This evening through Friday)
Issued at 358 PM CDT Thu Apr 27 2017

The low pressure system responsible for the past two days of wintry
precipitation is finally, slowly making its exit over eastern Lake
Superior today into central Ontario tonight towards Hudson Bay on
Friday. As the low matures and lifts north, the upper Midwest will
be within the colder northwest flow resulting in occasional snow
showers impacting parts of northeast Minnesota through Friday,
though little additional snowfall accumulation is expected. Some
sunshine Friday as the low exits with temperatures a bit warmer than
today, breaking the freezing mark for most locations in the low to
mid 40s outside of the Minnesota Arrowhead region.

.LONG TERM...(Friday night through Thursday)
Issued at 358 PM CDT Thu Apr 27 2017

The extended begins with a vertically stacked low moving into Hudson
Bay. Behind the exiting system, a low amplitude ridge will build
from the Northern Plains into the Upper Midwest. This will bring
sunny skies to the region with mild temperatures in comparison to
the past couple of days. Highs on Saturday range from the 40`s
near the Lake Superior shoreline, to the 50`s inland.

Focus then turns to the next potential winter storm on Sunday into
early next week. A positively tilted trough axis will dig from the
Intermountain West on Saturday into the Central Plains by early
Sunday. The trough will become neutrally/slightly negatively tilted
before lifting northeastward late on Sunday. In response to the
trough, a surface low will develop somewhere near OK/KS/MO/AR. The
low will move north-northeastward into the Mid Mississippi River
Valley by Sunday evening. This will spread precipitation into the
region from south to north as Sunday progresses. Initially,
precipitation will begin as light snow during the morning hours, but
will change over to all rain as temperatures rise. The low will
continue progressing northeastward on Monday into the western Great
Lakes. The low will exit into Ontario by late on Monday or early on
Tuesday. Below 0 degree Celsius 850 hPa air will advect into the
Northland Sunday evening through Tuesday. Precipitation types
continue to be a concern as the latest deterministic guidance have
varying thermal profiles, with the GFS/CMC bringing more in the way
of a snow/wintry mix and the ECMWF bringing all rain with some mix.
In addition, the track and progression of the low differ with the
GFS/CMC being much faster and farther east than the ECWMF. Suspect
that the latent heat release from convection firing across the
Southeast US/Ohio River Valley may be the cause for a more easterly
track, with more convection in the GFS/CMC compared to the ECMWF.
Based on these differences, just left mainly a rain/snow mix at this
point due to the uncertainty. However, a wintry mix of rain, snow,
freezing rain and sleet cannot be ruled out with this system. In
addition, several inches of accumulating snow is possible along with
possible icing. It is still too early to determine specific amounts,
so those with travel plans on Sunday and early next week will want
to stay tuned for future updates.

Behind the departing low another low amplitude ridge will build into
the region form the northwest mid-week bringing drier weather and
milder temperatures for Wednesday/Thursday. Precipitation chances
return on Thursday as a shortwave trough digs into northern
Minnesota from central Canada.

Temperatures will remain below normal through the extended period.
Low temperatures will generally be in the 20`s and 30`s. High
temperatures will fluctuate through the extended with the coolest
readings on Sunday and Monday. Readings on Sunday and Monday will
range from the 30`s to 40`s throughout the Northland.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1243 PM CDT Thu Apr 27 2017

A surface low will move northeastward from Lake Michigan this
afternoon into Ontario tonight. Aloft, a 500 hPa cutoff will move
into Ontario where it slowly move northeastward through the
period. This will keep the region in MVFR ceilings with borderline
IFR conditions through the forecast. Scattered snow showers will
linger across the region, but expect more widespread activity
across far northeast Minnesota. More confident in snow showers at
KINL, but less certain at KHIB as it may remain on the southern
periphery of the shower activity per the NAM/ARW/NMM/RAP. Expect
visibility reduction in the heavier snow showers, but uncertain at
this point in time how low visibilities will get. KBRD may break
out to VFR conditions Friday morning as ceilings scatter out with
high pressure building in from the Northern Plains.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  25  42  27  49 /  10   0   0   0
INL  23  41  22  53 /  50  20   0   0
BRD  26  45  27  54 /  10   0   0   0
HYR  26  46  27  52 /  10   0   0   0
ASX  25  44  29  47 /  10   0  10   0

&&

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

$$

SHORT TERM...JJM
LONG TERM...WL
AVIATION...WL


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