Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Billings Montana
801 PM MDT Friday Oct 24 2014
made some minor tweaks to the winds...especially around
Livingston. Otherwise the forecast trends look good. Reimer
Short term...valid for Sat and sun...
Stronger westerly flow aloft will get pushed north tonight as an
upper level ridge briefly strengthens over the region. A few
showers along the Crazy Mountains towards the Musselshell river
will continue to slowly shift north. This activity will linger in
to the evening hours so added isolated probability of precipitation but these showers are
fast moving and producing little moisture.
Upper level ridge builds into the region on Saturday and shifts
eastward which brings warmer temperatures aloft and allows some
pressure falls over northern Montana to bring a favorable pressure
gradient for mixing. Should see another 70 degree today with lots
of sun and winds relatively light for such a warm fall day. This
will be the 13th 70 degree day of October 2014 after 2013 having
no 70 degree days in October.
Pressure falls continue Saturday night to keep mild conditions in
place as a strong wave moves into the Pacific northwest.
Accelerating middle level flow will line up with pressure gradients
to bring increasing winds along the foothills but a couple of
factors may be limiting strength of winds. Not sure how strong
mountaintop inversion will be given some weak lift approaching
the area and also not sure if the surface pressure gradient
orientation wil be favorable given how far into southeast Montana
it is expected to extend. Did raise winds along the foothills and
the Livingston area around daybreak Sunday.
Shower activity will move into southwest Montana early Sunday and
will push into the plains Sunday afternoon. Models do indicate a
cold front working through the area but wind shift may not be all
that noticeable as the front jumps into the preexisting leeside
trough. Relatively light winds for a fall frontal passage since
cold air advection behind the front is not dramatic. Timing of the
front looks to be near day break for western areas and around noon
for southeast Montana...so there is a chance for some daytime
Models hint at frontogenesis along the Montana/Wyoming border as the main
disturbance approaches. WRF shows this as having a convective
component which may be over doing the developmental aspect of this
feature given that the instability does not look to be that deep.
Will definitely be a cooler night with winds decreasing late.
Long term...valid for Monday...Tue...Wed...Thu...Fri...
The GFS/Canadian models remain in fairly close agreement whereas
the European model (ecmwf) has shown run to run inconsistency. Have trended the
forecast toward the GFS.
Cool and unsettled weather pattern setting up for Monday as an
unstable northwest flow sets up behind exiting trough of low
pressure. Upper wave will drive a cold front across the area which
will bring snow showers to the mountains and also our far western
zones...mainly from Livingston to Harlowton. Rain showers will be
possible over the central and eastern zones. High pressure ridge
begins to build across the region Monday night and will bring dry
weather through Tuesday. This upper ridge will quickly flatten out
on Wednesday as by more energy will be moving in from the West
Coast. Strong jet moving across the area which will bring some
weak q vector forcing for scattered showers. The better chance for
precipitation will be confined to the Southwest Mountains. Drying
to take place Thursday and Friday as another ridge of high
pressure builds in over Montana. This will push temperatures back
to above normal for this time of the year. Richmond
VFR conditions expected the rest of tonight and tomorrow across
the area...with wind remaining generally less than 10 knots.
Preliminary point temp/pops...
Sat sun Monday Tuesday Wednesday Thursday Friday
bil 041/070 047/062 037/052 031/055 037/059 035/058 034/061
00/u 03/west 33/west 11/b 13/west 21/b 10/b
lvm 039/069 041/055 032/046 029/051 034/054 034/055 032/054
10/north 13/west 33/west 11/b 23/west 22/west 10/b
hdn 037/073 039/065 035/053 030/056 033/060 033/058 032/062
00/u 03/west 33/west 11/b 12/west 21/b 10/b
mls 038/070 041/066 037/050 029/054 033/059 031/055 030/059
00/u 02/west 22/west 11/b 12/west 11/b 10/b
4bq 038/071 043/068 037/050 029/054 032/059 033/056 033/062
00/u 02/west 42/west 11/b 12/west 11/b 10/b
bhk 034/065 038/067 036/046 027/048 029/056 029/051 029/059
00/u 02/west 32/west 21/b 12/west 11/b 10/b
shr 037/073 041/067 032/050 028/054 029/059 029/057 030/058
00/u 02/west 44/west 11/u 12/west 22/west 10/b