Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Duluth Minnesota
530 am CST Friday Feb 27 2015
Short term...(today through saturday)
issued at 356 am CST Friday Feb 27 2015
At 345 am...it was another morning of very cold temperatures
across the Northland. Temperatures ranged from 26 below zero at
Crane Lake to 4 below zero at Ashland. There were some very cold
temperatures in northwest WI as well...with temperatures generally in the teens
below zero. Skies were generally clear. Wind chill readings were
generally in the single digits and teens below zero...although
there were a few locations near 25 below zero.
The main focus for today is high temperatures. We have definitely
been seeing warmer than MOS temperatures for daytime highs. This is
fairly common this time of year due to the Pine Tree effect. Will
continue to go with a bit warmer than MOS temperatures across the County Warning Area
today...with highs in the middle to upper teens. Sunny skies are in
store for the County Warning Area...although some high clouds are expected to move
through at times.
Temperatures will once again fall into the single digits and teens
below zero tonight under mostly clear skies. We could again see a
period of brief wind chill values approaching 25 below zero.
Approaching low pressure will bring a gradual increase in clouds
from west to east on Saturday...although a good deal of sunshine
is expected for a fair amount of the day. Highs will generally be
in the 20s. There could even be a few snow showers across portions
of north central Minnesota during the afternoon.
Long term...(saturday night through thursday)
issued at 356 am CST Friday Feb 27 2015
The gradual warming trend continues through the weekend and into the
first half of next week. A Colorado low pressure system will lead to
a chance of snowfall late Monday through Tuesday...and while some
uncertainty in the low track exists guidance has been generally
trending northward with the system. Later in the work week
northwesterly flow will bring a return to well below normal
Confidence for the early week system has been below normal for the
past few days due to the complex nature of the middle/low level
pattern. On the synoptic scale two major features will combine to
bring a chance for decent snowfall accumulations to at least parts
of the region...but the spread of guidance is still large enough
that little to snowfall for this time period remains a possibility.
At the surface we will be watching for a Colorado low to develop in
response to deep middle-level trough across the western Continental U.S. On Monday.
This feature will lift northeastward into the Midwest with the
support of a middle-level shortwave impulse. To the north an upper low
will move east through central Saskatchewan/Manitoba with the trough
axis moving across the Northland late Tuesday night. These two
features will not line up well...and while the best large scale
forcing for northern Minnesota and northwest Wisconsin will be late
Tuesday as the stronger northerly upper level support develops...the
best low/middle level moisture will be gone. The storm that evolves out
of the Colorado low will certainly impact a large portion of the
Midwest and the eastern third of the Continental U.S....our County Warning Area will be just on
the northwest fringe.
Sat night/sun/Mon...a chance for light snow Sat night and late
Sunday due to increased moisture and some weak forcing in place.
Winds breezy Sunday and Monday afternoon...with gusts approaching
25kts on Monday as pressure gradient increases across the region due
to an area of high pressure across the Ohio Valley and low over
northern Manitoba. Partly/mostly cloudy on Sat
night/Sunday...becoming mostly sunny by Monday. Temperatures approaching
normal...with highs in the middle to upper 20s.
Late Mon/tues/Wed...increasing clouds as well as a chance for
snowfall. Best chance for snowfall Tuesday afternoon into Tuesday
evening...but guidance is all over the place as far as timing GOES.
Gem is faster than European model (ecmwf) while the GFS keeps things mainly south of
the County Warning Area. Too far out to get serious about snowfall amounts...and as
stated above there still exists a possibility that we see little to
no accumulation. Temperatures warmest on Tuesday in the upper
20s...then diving into the single digit/teens for highs on
Thursday...colder with decreasing clouds. Highs in the teens with
lows 5 to 15 below zero on Wednesday night into Thursday
morning...and a tight pressure gradient across the region could lead
to breezy conditions on Thursday.
Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 530 am CST Friday Feb 27 2015
VFR conditions through the taf period at all taf sites. Light west
to west/southwest winds today into this evening..with near calm
winds overnight as an area of high pressure moves from east to west
across the middle-Mississippi Valley. A few gusts to 15-20kts at dlh
this afternoon...but since prevailing winds will remain less than
10kts have opted to use a tempo group to depict the sporadic nature
of the higher gusts. Skies clear through the period...except for
maybe some high level cirrus across inl early this morning and very
Preliminary point temps/pops...
dlh 17 -7 21 8 / 0 0 0 20
inl 16 -13 20 1 / 0 0 20 20
brd 17 -6 21 7 / 0 0 10 20
hyr 16 -11 19 7 / 0 0 0 20
asx 18 -3 23 11 / 0 0 0 10