Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 272100

Area Forecast Discussion
National Weather Service Billings MT
300 PM MDT Tue Oct 27 2020


Tonight through Wednesday night...

Satellite imagery shows northwest flow over the region, with one
shortwave departing thru the northern plains and another upstream
over northern Alberta. Due to the passage of the initial wave we
are now seeing the gradient begin to relax as the isallobaric wind
is easterly. Temps in the low-mid 40s along with a gradual trend
down in gusts have ended the blowing/drifting snow risk along our
western have cancelled all remaining winter
highlights. Winds will nonetheless remain gusty (35-50 mph) along
the foothills for the next several hours. Upstream shortwave will
be followed by a push of lee side pressure rises which will
decrease the downslope surface winds further. Winds on Wednesday
will be lighter than today.

Winds aloft will back slightly ahead of the next approaching
Pacific shortwave late Wednesday night. This will allow for
another period of lee side pressure falls with gap areas likely to
become more involved than this most recent wind event. Could see
50 mph gusts at Livingston and Nye (and probably Big Timber) by
12z Thursday.

Temperatures have warmed into the 40s and even lower 50s along our
foothills today...but are cooler over the snow-covered lower
elevations. We will see the air mass cool somewhat tomorrow in the
wake of the late night front, but in reality (after a warmer
night) this should yield high temps near where they are today. No
chance of precip over the next 36 hours...only scattered to broken
high cloud cover.


Thursday through Tuesday...

Not much change to the extended forecast. Dry NW flow on Thursday
will become zonal on Friday. Pressure gradient Thu. morning
supported gusty winds in KLVM/Nye areas and Big Timber, so bumped
up winds in these areas. Also, models had a favorable pressure
gradient for gusty winds in the gap areas late Thu. night through
Friday morning, so bumped up winds in these locations. A shortwave
trough will swing through the area Fri. night, pushing a cold
front through the region. NBM continues to show no precipitation
with this front. The EC Ensemble Wind Gust Chart and the NAEFS/EC
Tables were in good agreement in showing decent wind gusts late
Friday into Saturday. NBM had a good handle on the gusts. NW flow
on Saturday will give way to strong upper ridging for Sunday and
Monday. Model clusters showed general ridging for Tuesday, but
some of the members had a slightly cyclonic flow SW of low
pressure in Canada. Pressure gradient Sun. morning and late Sun.
night again favored stronger winds in KLVM/Nye and Big Timber so
increased winds in these areas. Temps in the 40s and 50s Thu. and
Fri. will lower into the 40s behind the front on Saturday. Highs
will then warm well into the 50s by Monday. Arthur



Gusty SW-W winds will continue from KBIL westward through the
evening. Expect gusts to 40 kts at KLVM-K6S0-KHWQ, and 30 kts at
KBIL. Otherwise, VFR will prevail under scattered to broken high
clouds. JKL



    Wed     Thu     Fri     Sat     Sun     Mon     Tue
BIL 030/042 031/047 031/051 031/044 028/052 035/056 036/055
    00/B    00/B    00/U    00/U    00/U    00/U    00/U
LVM 029/048 032/053 030/055 029/050 028/057 031/059 031/059
    00/B    00/N    00/N    10/U    00/N    00/N    00/U
HDN 022/040 023/048 025/052 028/045 024/052 029/057 030/058
    00/B    00/B    00/U    00/B    00/U    00/U    00/U
MLS 026/041 024/048 027/054 031/042 024/052 031/057 034/057
    00/B    00/B    00/U    00/B    00/U    00/U    00/U
4BQ 026/042 023/050 027/055 032/043 025/052 032/057 034/058
    00/B    00/B    00/U    00/U    00/U    00/U    00/U
BHK 025/040 022/045 026/052 029/039 021/048 030/055 032/054
    00/B    00/B    00/U    00/B    00/U    00/U    00/U
SHR 024/045 025/055 027/059 029/046 024/057 030/061 031/061
    00/B    00/U    00/U    10/U    00/U    00/U    00/U




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