Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Billings Montana
328 am MST Sat Feb 6 2016
Short term...valid for today and sun...
High wind impacts are the main issue in the short term. Confidence
is low in just how things will play out as the fast moving
dynamics with approaching wave are rarely handled well by models.
That said...we will see strong winds today along and behind
frontal passage. I actually feel good for strong winds in far east
on Sunday for reasons outlined below.
The evening shift upgraded the high wind watch for much of the
west and northern tier of our forecast area. Despite weak pressure
rises on forecasts this looks prudent given best combination of
unusually steep lapses rates...mixing and impressive 700mb wind
speeds affect these areas. Harlowton has in fact already hit
warning criteria early this morning...and gap areas Livingston and
Nye are hitting advisory criteria with peak wind of 71 miles per hour at
Livingston so far.
Forecast issue then deals with remaining zones under high wind
watch. First thing we looked at was potential for mountain wave
at Sheridan. Vigorous short wave now seen on satellite moving
through into Pacific northwest will quickly push into our region by middle
to late morning. BUFKIT soundings and cross sections do not show a
critical layer low enough to affectively produce a mountain wave.
So mountain wave activity does not look likely though short term
forecasts and upstream observations will need to be monitored through
the day. Pressure rises behind front also pretty weak this far
south in in our County Warning Area. BUFKIT does indicate potential for strong
winds in the boundary layer from evening into early morning
hours. At this point we feel keeping the watch up for Sheridan
area is best and let next shift upgrade should confidence
increase through the day.
East/southeast zones...although pressure rises again are not that
impressive...initial push of front may mix down some 60 miles per hour winds
this afternoon due to very steep low level lapse rates in place.
But a more extended period of strong winds looks better for
tomorrow in far eastern zones as jet streak sets up over the area
and lapse rates again are over up to 8 c/km on WRF forecasts. 700mb
wind speeds are around 60 kts over this area as well. Will upgrade
remaining watches in these zones to High Wind Warning. Bt
Long term...valid for Monday...Tue...Wed...Thu...Fri...
Models continued in good agreement in showing a strong ridge axis
anchored west of the forecast area through Friday. The ridge will begin
to shift east on Sat. Ensembles were in good agreement until the
Friday-Sat time frame. Expect a warm and dry period with windy
conditions from kbil west. High temperatures will reach the 50s in
many locations through the week. Did not see any strong pressure
gradients that suggested possible wind highlights at this time. Of
course...in this type of pattern...there is always the possibility
of a backdoor cold front moving in from the NE so will keep
watching for this on each successive model run. Arthur
A strong cold front will sweep east across the area through early this
afternoon. The front will usher in very strong westerly surface
winds that will become northwest. Expect wind gusts of 55 to 60 knots over
Big Timber and klvm this morning. Wind gusts in excess of 50 knots
will overspread much of the remainder of the area this
afternoon...including kbil and kmls. Gusts are not expected to be
as high over kshr. Wind gusts in excess of 50 knots will affect all
terminals this evening and then winds will decrease from west to east
through the night. Expect localized to areas of mountain
obscuration through tonight. Arthur
Preliminary point temp/pops...
Today sun Monday Tuesday Wednesday Thursday Friday
bil 050 029/044 028/053 035/057 036/056 035/055 033/051
1/north 10/north 01/north 00/north 00/north 00/north 11/b
lvm 044 025/041 030/049 036/052 036/051 035/049 033/048
2/west 10/north 01/north 00/north 00/north 01/north 11/north
hdn 050 026/044 022/051 030/055 030/054 029/052 027/049
1/north 10/north 01/b 00/u 00/u 01/b 11/b
mls 051 028/042 021/046 031/052 031/051 029/049 027/043
1/north 10/north 01/b 11/b 00/u 11/b 11/b
4bq 049 026/039 021/044 030/053 031/052 028/050 028/047
1/north 10/north 01/b 11/b 00/u 01/b 11/b
bhk 049 026/037 017/041 028/048 030/047 026/044 024/039
1/north 10/north 01/b 11/b 10/u 11/b 11/b
shr 048 024/038 021/048 029/054 027/053 026/052 026/049
1/north 10/north 01/b 00/u 00/u 00/u 11/b
Montana...High Wind Warning in effect until 11 PM MST this evening for
High Wind Warning in effect from 8 am this morning to 8 PM
MST Sunday for zones 32-33.
High Wind Warning in effect from 2 PM this afternoon to 8 PM
MST Sunday for zones 36-37.
High wind watch in effect through this evening for zones
Wind Advisory in effect until 5 am MST Sunday for zones
Wyoming...high wind watch in effect through this evening for zone 99.