Area Forecast Discussion
Issued by NWS Duluth, MN
FXUS63 KDLH 260521
Area Forecast Discussion
National Weather Service Duluth MN
1121 PM CST Fri Nov 25 2016
.SHORT TERM...(This evening through Saturday)
Issued at 338 PM CST Fri Nov 25 2016
It has been a cloudy, gloomy day across the forecast area with weak
ridging at the surface. Most of our moisture is trapped beneath the
low level inversion, as shown on the KINL sounding from this
morning. Aloft we have cyclonic flow on the southwest side of an
upper low over northwest Ontario, with a few weaker waves within
that flow. We have just enough weak lift to generate light snow
showers/drizzle, depending on the amount of ice coming in from
aloft. Have kept enough pops around for some evening snow
showers/drizzle/freezing drizzle depending on surface temperatures,
but after midnight we should lose not only our ice from aloft but
also any weak lift that might support drizzle/freezing drizzle.
Theoretically, the freezing drizzle should be patchy enough to not
make a very widespread impact, but may be locally significant at
times this evening. Have kept to moderated min temperatures, and
have gone with a little warmer than the average guidance overnight.
Saturday we should see enough dry air and warm air advection move in
from the west to finally mix out these low clouds, only to see
stratocumulus develop shortly after the stratus breaks up. Have
gone with max temps in the mid 30s, expecting only small amounts of
sunshine. However, if we can break up more of the clouds
temperatures will be warmer than I currently have forecast. With
the upper level ridge finally building in an precipitation chances
should be gone by early morning.
.LONG TERM...(Saturday night through Friday)
Issued at 354 PM CST Fri Nov 25 2016
Chief issues during the long term period involve storm system
arriving Sunday night and lingering through much of the week.
Precipitation timing, type, and amounts are the main challenge. No
significant changes to previous forecast with this update.
Mid-level ridging will be present across the region at the start of
the period and a deep trough digging into the Intermountain West.
The approaching trough will shunt the ridge to the east through the
day Sunday. Lee cyclogenesis will yield a surface low over northeast
Colorado by early afternoon Sunday. The surface low will lift
northeastward into the eastern Dakotas by late Sunday night while
the mid-level trough transitions to a cutoff low. A strong surge of
warm air from the south continues to point to rain moving through
the Northland beginning late Sunday night or Monday morning.
Deterministic guidance maintains a ribbon of elevated instability
lifting into the area Sunday night through Monday evening, which
could result in isolated thunderstorms. Precipitation may be heavy
enough to overcome the warm low-levels with a rain/snow mix or a
brief change to all snow Sunday night and early Monday.
The stacked low will slowly wobble eastward Tuesday through the end
of the week. Temperatures will gradually cool and precipitation
type will slowly shift toward all snow. A rain/snow mix will be
possible during daylight hours for the remainder of the week. Several
inches of nuisance accumulation are possible across the area between
late Monday night and Friday.
Temperatures through the long range will remain near to much above
normal. Highs will be in the middle 30s to low 40s on Sunday,
trending warmer Monday with values in the upper 30s to near 50
degrees on Monday. Low temperatures will be in the 20s Saturday
night and the 30s Monday night. For the remainder of the period look
for highs in the 30s and overnight lows in the 20s.
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1118 PM CST Fri Nov 25 2016
IFR and LIFR ceilings and fog will prevail through day break. The
arrival of dry air will gradually erode the low clouds Saturday.
However, confident is not high all locations will clear out and
expect the low clouds and fog to quickly redevelop Saturday
.PRELIMINARY POINT TEMPS/POPS...
DLH 28 36 27 39 / 20 0 0 0
INL 28 38 24 39 / 20 0 0 0
BRD 26 38 26 40 / 10 0 10 10
HYR 28 39 25 42 / 10 0 0 0
ASX 30 40 27 43 / 20 0 0 0