Area Forecast Discussion
Issued by NWS Duluth, MN
FXUS63 KDLH 172144 AAA
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
344 PM CST Fri Feb 17 2017
.SHORT TERM...(This evening through Saturday)
Issued at 342 PM CST Fri Feb 17 2017
At 330 PM...There was a pronounced upper-level ridge over the
Upper Midwest, western Great Lakes, and Ontario region, which was
maintaining clear skies under the ridge. An area of low pressure
was over northwest Manitoba, and its cool front stretched south to
the border area between Minnesota and the Dakotas. There was very
unseasonably warm air across the western Great Lakes region. The
850 hpa temperature in the southerly flow, ahead of the
approaching cool front, were 10 to 14 degrees Celsius, including
across the Northland. The Northland had temperatures in the 50s
(about 25 to 30 degrees above seasonable normal high temperatures)
with light southerly winds.
Tonight...The upper-ridge will shift east through the Great
Lakes, and the cool front will swing through the Northland. There
have been concerns that fog and low-level stratus would develop
tonight, but think models are once again overestimating low-level
moisture. For instance, the GFS, which is suggesting stratus
across northern Minnesota tonight, has that stratus depicted
upstream over south-central Canada, where there is mostly clear
skies right now. Also, while there has been plenty of melting snow
today, which would obviously add some moisture into the boundary
layer, think there will be too much wind (about 5 to 10 mph) and
boundary layer mixing tonight to result in any significant fog.
Took the patchy fog out of the forecast, but not saying its
impossible, just very unlikely. Overall, think most of the
Northland should see clear skies tonight, but there could be some
stratus across the far northern Arrowhead. The winds and
relatively warm air will help bolster the temperatures, so
temperatures will only fall to near the freezing mark.
Saturday...The Northland should have another fairly sunny day
with light westerly flow. A surface ridge will be approaching from
the west, and upper-level cloud cover will likely begin to spread
into the Northland in the middle to late afternoon. Even though
the overall atmosphere will be cooler (850 hpa temperatures of 2
to 4 degrees Celsius), we still expect highs to reach the well
into the 40s given the sunshine and relatively good head start to
temperatures in the warming.
.LONG TERM...(Saturday night through Friday)
Issued at 342 PM CST Fri Feb 17 2017
Unseasonably warm temperatures will continue through the long
term with two storm systems moving through the region Monday and
early Tuesday and again Thursday and Friday.
Quiet and warm conditions will continue Saturday evening with an
upper-level ridge building across the Upper Mississippi Valley
overnight and Sunday. With southerly winds and expected snow melt,
look for areas of fog to develop overnight.
Attention then shifts to a deep trough advancing eastward through
the Rockies and into the Plains Sunday night and Monday. Lee
cyclogenesis will occur over northern Colorado and southern
Wyoming by Sunday evening. The ridge axis will shift farther
eastward opening a return flow of Gulf moisture into the region.
The low is expected to move northeastward into Manitoba and far
northern Ontario by Tuesday morning, lifting a warm front
northeastward through the area Monday afternoon and evening. A mix
of rain and snow is forecast to spread into the Northland Monday
morning, changing to all rain during the day, then back to a mix
in our northern zones Monday night. With the surge of warm and
moist air aloft, a broad area of non-zero MUCAPE will evolve over
Minnesota and Wisconsin. Have expanded the mentions of
thunderstorms with this afternoon`s package. There is certainly a
potential all of the Northland may hear a rumble or two of
thunder. Rainfall amounts of one-quarter to one inch are possible.
The recent warm temperatures will ripen the snowpack across the
Northland and melt some of the snow by Monday. Forecast rainfall
will contribute to the melting process and will likely raise
stream and river levels. There is some reserve capacity in the
system, but we will continue to keep a close eye on area hydrology
through the weekend.
Another fast-moving clipper will graze the Northland Tuesday
night and early Wednesday bringing a few rain or snow showers to
areas north of the Iron Range. Attention then shifts to another
potential storm system for Thursday and Friday. An upper-level
trough will move across the Intermountain West Tuesday night and
Wednesday, and will emerge onto the Plains Thursday. Deterministic
and ensemble guidance has come into better agreement in handling
this system during the past 24 hours. While consensus generally
breeds confidence, the extremely warm conditions over the past
several weeks leave some doubts. Based on this afternoon`s
consensus, there is a potential for a swath of accumulating snow
from the eastern Dakotas across much of Minnesota and Wisconsin.
Anyone with travel plans late next week and into the weekend is
encouraged to keep up with the forecast through the week.
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1157 AM CST Fri Feb 17 2017
VFR conditions to continue into tonight as high pressure drifts
farther east and a modified Pacific cool front moves through
northern Minnesota. An area of low pressure will move through
northern Manitoba and into far northern Ontario tonight. Moisture
remains quite limited and there may be an increase in VFR cloud
cover overnight. Airmass over the region is much drier than
forecast models suggest. With the lack of stratus last night and
early this morning, am not convinced the BUFR soundings from the
GFS and NAM actually reflect the amount of moisture available for
tonight. Kept a mention of FEW and SCT around 1kft overnight and
Saturday morning. Introduced some BR at HYR and maintained the 6SM
BR at BRD. There`s certainly a potential for lower-half MVFR or
IFR CIGS overnight, but think the odds of stratus developing is
quite low. Models seem to think there is a more snow to our south,
which would be melting today and increasing low-level moisture.
Behind the cool front winds will veer westerly and wind speeds
aloft will increase sharply. Added LLWS at all sites overnight
through much of Saturday morning. Confidence in this forecast
package is above average.
Issued at 340 PM CST Fri Feb 17 2017
Record Highs for February 17...
Duluth................ 52 in 1981
International Falls... 52 in 1907
Record Warmest Lows for February 18...
Duluth................ 35 in 1981
International Falls... 35 in 1981
Record Highs for February 18...
Duluth................ 53 in 1981
International Falls... 49 in 1954
Record Warmest Lows for February 19...
Duluth................ 35 in 1930
International Falls... 32 in 2016
Record Highs for February 19...
Duluth................ 51 in 1930
International Falls... 47 in 1994
Record Warmest Lows for February 20...
Duluth................ 33 in 1954
International Falls... 32 in 1915
Record Highs for February 20...
Duluth................ 54 in 1877
International Falls... 48 in 1990
Record Warmest Lows for February 21...
Duluth................ 33 in 1878
International Falls... 29 in 1981
Record Highs for February 21...
Duluth................ 57 in 1877
International Falls... 50 in 2000
Record Warmest Lows for February 22...
Duluth................ 35 in 1930
International Falls... 32 in 1998
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 45 28 46 / 0 0 0 0
INL 32 42 25 44 / 0 0 0 0
BRD 31 47 30 52 / 0 0 0 0
HYR 31 46 28 52 / 0 0 0 0
ASX 34 48 29 50 / 0 0 0 0