Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Billings Montana
338 am MST Thursday Nov 27 2014
Short term...valid for today and Friday...
Transition to a warmer couple of days beginning this morning as a
energetic flow aloft GOES through subtle backing and allows a warm
front to continue progressing through the region. Western zones
and higher elevations already reflect this transition with
temperatures in the 4os while cold air lingers as far west as
Reedpoint and Harlowton. Vwp profile in Billings shows 20 to 25 knots
westerly winds 2kft above the ground so transition to warmer
temperatures will pretty fast when it begins to occur around daybreak for
central areas. The substantial moisture received today is causing
fog in sheltered areas like Livingston or where local upslope is
occurring like Billings. This should dissipate around 12z when the
mixing begins to strengthen.
Further east the isentropic lift is stronger and light
precipitation is showing up on radar but coverage is limited. This
should be maintained for the morning hours but will dissipate by
afternoon as the strong warmfront blows through the region.
Despite snow cover many areas will see middle to upper 40s.
Weather story will be wind for the next 48 hours along with
temperatures climbing into the 50s. Leeside troughing due to the
strong winds aloft and high pressure over southeast Idaho will
support strong gap flow winds for a long duration. Current Wind
Advisory looks good extending all the way into Saturday.
Friday is going to be a warm day and in the 50s which could
approach records. Moist ground with some evaporative cooling could
hold temperatures into the middle 50s with upper 40s over extreme
southeast Montana. Heights falling over the western zones begin to
allow an increase in mountain shower activity.
Friday night looks mild early but an Arctic front will begin
moving into the northern zones after midnight and reach Billings
around 4 am. This is a much more potent cold front then the last
system from a temperature perspective. Precipitation does look to
lag into the colder air so expect Friday night to be dry. Borsum
Long term...valid for Sat...sun...Mon...Tue...Wed...
Blast of cold along with some snow accumulation coming for this
weekend. Very high confidence exists in this initial phase of the
extended period...with much more uncertainty beyond Monday.
Cold air currently pooling in northern British Columbia/Alberta will push
southward and reach our County Warning Area Saturday. Snow will develop behind the
frontal passage and continue into Sunday...with a tapering off by afternoon
as upper trough weakens and pushes east. Uncertainty exists with the
frontal passage timing but favor the faster European model (ecmwf)/Canadian which suggest
arrival into Billings around 12z Sat morning. Strong cold
advection will commence and greatest threat of precipitation should lag
the front by several hours...and this should greatly reduce any
potential for a fast freeze of wet roads. Have also favored the
European model (ecmwf) with regard to the strength of the upper trough...with a bit
more amplification and dynamics lasting into Sunday...so have
adjusted probability of precipitation into Sunday in our south to account for this.
Dendritic layer will be deep in the initial stages of snowfall
but as temperatures turn colder the snow should become finer...ie late
Sat night into Sunday. Overall looks like a few inches of snow
especially for our west and south...along with temperatures falling hard
to near zero Saturday night. Could even see some issues with wind
chills in our east by late Sat night as core of surface high not
expected to arrive until during the day on Sunday. Temperatures on Sunday
will be only in the single digits and teens.
Surface high will retreat quickly Sunday night and Monday allowing for
a moderation in temperatures...but todays models not quite as aggressive
with downslope warming/winds on Monday with more energy moving in
quickly from the northwest...keeping ridging somewhat suppressed. Models
diverge a great deal beyond Monday night clipper...with the GFS
taking weak energy from the Pacific coast through the central rockies and
the European model (ecmwf) building a ridge ahead of a weakening Pacific low. Either
way do not see anything too dynamic in the Tuesday-Thursday time frame...
and we should see gradual moderation with temperatures returning to near
normal by the middle week.
Areas of fog...low clouds and light precipitation will produce MVFR or
lower flight conditions east of the foothills early this morning.
A transition to VFR conditions can be expected through the morning
from west to east as drier downslope winds develop off the mountains
expect improvement at kbil and kshr by 11-13z...then kmls and
kbhk by 18z. VFR will prevail across the area tonight. Mountains
will be obscured occasionally over the next 24 hours.
Winds along the foothills will be strong today and tonight with
gusts likely to exceed 50 kts at klvm. Wind gusts to 30 kts can be
expected at kbil.
Preliminary point temp/pops...
Today Friday Sat sun Monday Tuesday Wednesday
bil 049 037/054 027/029 902/010 004/031 019/035 015/033
1/north 01/east 16/S 75/S 10/b 22/j 11/b
lvm 052 043/053 033/035 002/016 007/033 025/037 017/036
1/north 11/north 37/o 74/S 11/b 22/j 11/b
hdn 050 031/054 024/030 901/010 001/031 014/035 012/034
1/east 02/west 14/S 74/S 10/b 22/j 11/b
mls 044 032/048 019/020 903/008 901/026 014/027 007/028
3/r 11/east 25/S 52/S 10/u 12/j 11/b
4bq 050 031/053 025/039 002/009 901/031 016/035 011/033
1/east 11/east 12/S 53/S 10/b 12/j 11/b
bhk 038 029/046 022/024 902/006 903/024 014/026 006/026
4/r 11/east 14/S 52/S 00/u 11/b 11/b
shr 050 032/052 028/039 003/011 000/034 019/037 013/036
1/north 01/east 12/S 76/S 10/b 22/j 11/b
Montana...Wind Advisory in effect until noon MST Saturday for zones