Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Duluth Minnesota
1110 PM CST Friday Feb 27 2015
Short term...(this evening through saturday)
issued at 312 PM CST Friday Feb 27 2015
An area of high pressure and dry air will keep the Northland precipitation
free through much of the short term period. There will be some
increase in moisture late in the period with a chance for some light
snow over western areas Saturday afternoon.
There will be some increase in high clouds tonight...mainly over far
northern areas...otherwise look for mainly clear skies. Tonights
lows will be well below zero...but not be as cold as last night.
There may be a few locales that near wind chills around 20 to 25
Clouds will gradually increase from west to east through the day
Saturday as a trough moves toward the Northland. Forcing does not
look particularly strong and moisture remains limited. We have an
area of small probability of precipitation for some snow over our far western zones...but
little accumulation is expected. Highs Saturday will range from the
upper teens to lower twenties.
Long term...(saturday night through friday)
issued at 312 PM CST Friday Feb 27 2015
A low pressure trough will move through the Northland Saturday night
and Sunday. The cloud cover and SW flow Saturday night will bolster
temperatures and put an end to the string of subzero nights. The
trough could produce a dusting of snow as it moves through the
region Saturday night and Sunday.
A clearing trend is expected Sunday night as surface high pressure
ridge moves through the Northland. Sunday night low temperatures
will be subzero or close to zero thanks to the clear skies.
The sunny skies will continue into Monday as SW flow develops in the
wake of the passing high pressure and an approaching trough in the
The models are still indicating the Northland could be affected by a
large storm system during the Monday night and Tuesday time frame. A
Colorado low will move into the plains early Tuesday and reach the
southern Great Lakes by late Tuesday evening. The GFS/ECMWF/Gem low
tracks are surprising similar...from SW Kansas to north of Detroit.
The Northland will be on the north side of the system and stands a
good chance of at least getting some light snow. The far southeast forecast
area has the best chance for the forecast area of getting snowfall.
At this time...the models suggest the Northland will escape any
substantial snowfall from this system...but the southeast forecast area
could get up to a few inches.
A strong Arctic cold front will sweep through the Northland Tuesday
and Tuesday night in the wake of the passing Colorado low.
Temperatures will drop back down to about 20 degrees below normal
for the middle of the week. The coldest night will likely be
Wednesday night when a surface ridge of high pressure moves into the
Northland early Thursday. Temperatures will likely plummet to well
below zero early Thursday. Despite the cold morning...temperatures
should recover well Thursday afternoon thanks to the sunnier skies
and...increasingly more and more powerful sun angle...and the Pine
Tree albedo effect.
The models are still indicating milder...Pacific air will move into
the upper Midwest late in the weeks. The Northland stands to benefit
from this air...and should return to closer to normal by Friday.
Aviation...(for the 06z tafs through 06z Saturday night)
issued at 1110 PM CST Friday Feb 27 2015
VFR at the outset of the forecast with high pressure nearby. Low
pressure in the western Dakotas will move eastward on Saturday with
gusty southerly winds affecting all terminals by 18z. As a surface
trough gets closer Saturday evening...light snow will
develop/approach the terminals from west to east through the end
of the forecast. MVFR ceilings will reach brd by 02z with the light
Preliminary point temps/pops...
dlh -8 20 6 22 / 0 0 20 10
inl -12 22 3 17 / 0 20 20 10
brd -7 21 5 23 / 0 10 20 0
hyr -12 18 7 25 / 0 0 20 20
asx -5 22 9 25 / 0 0 20 10