Area Forecast Discussion
Issued by NWS Billings, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS65 KBYZ 230941

Area Forecast Discussion
National Weather Service Billings MT
341 AM MDT Sun Apr 23 2017

.SHORT TERM...valid for Tdy and Mon...

Deep trough moving onto the Pacific northwest coast this morning.
Mid level flow has backed with moisture at 700mb level increasing
over western zones. Shortwave energy is progged to eject out of
the trough as it moves inland today. Showers were increasing over
Idaho into far western Montana early this morning. Shortwave
energy will kick across western zones this morning and into
central zones this afternoon and produce scattered showers. Not a
great deal of surface cape available for thunder today, but enough
mid level cape present, so will keep thunder in the forecast.
Will keep the higher chance of showers over western and northwest
zones. Highs will be warmer today, but may be tempered by
increasing cloud cover.

More energy, albeit weaker, will stream across the area for a
continued chance of showers tonight. A stronger wave organizes for
Monday and Monday night and this will bring the best chance of
showers to western and central zones. The GFS was very robust with
QPF amounts over the west, mainly along the foothills, with over
an inch of QPF Monday trough Monday night. NAM was also heavy with
rain totals, but the ECMWF was much lighter. Will side with the
GFS as the EC seems strangely light on rain amounts given the
upslope component and QG forcing available. Looks like the
mountains could receive a hefty amount of snow with this system
should the GFS verify. Will keep the HWO running, along with the
weather story, but will hold off on a Watch for now given the
light QPF amounts of the EC. Should the EC move in the GFS
direction, may need to consider a Winter Storm Watch for the
mountains. Some wet snow will likely mix in over the foothills for
light accumulations Monday night, but it appears to be mainly a
rain event for locations below 6 thousand feet. TWH

.LONG TERM...valid for Tue...Wed...Thu...Fri...Sat...

Extended forecast begins with continued lower elevation rain and
mountain snow on Tuesday as models bring upper trough over the
region. Low-level upslope flow is expected for much of Tuesday,
indicating that rain should hang on most of the day. Some wet snow
is possible over Fallon and Carter Counties as northeasterly
winds advect cooler air into that area. For now think that ground
is warm enough to limit snow accumulations.

Semi-zonal, cyclonic flow takes hold behind the departing upper
trough. This pattern can produce more showers over the lower
elevations and snow in the mountains. A more organized upper low
is progged to track over UT and CO later in the week, which should
keep most of the heavier precipitation south of our area...but if
the track were to shift northward we could have another
widespread rain/mountain snow event affecting the area in the
Thursday night-Friday night timeframe.

High temperatures should generally be below normal, in the 40s
and 50s, for Tuesday-Friday.



Patchy fog is possible this morning over southeast Montana
possibly impacting KMLS and KBHK. Otherwise VFR will prevail. A
cold front will approach the area from the west this afternoon,
bringing scattered showers and isolated afternoon thunderstorms
with MVFR/IFR conditions. The precipitation will be mainly west of
KMLS today. Obscurations will increase over the
Beartooth/Absaroka and Crazy Mountains today. RMS/TWH



    Tdy Mon     Tue     Wed     Thu     Fri     Sat
BIL 066 042/058 038/049 036/053 037/051 036/051 036/056
    2/T 65/T    77/W    35/W    54/W    33/W    33/W
LVM 061 037/055 033/053 033/052 032/050 030/050 029/054
    5/T 67/T    76/T    46/T    45/W    54/W    33/W
HDN 069 042/061 038/051 035/057 038/053 036/053 036/057
    2/T 45/T    77/W    24/W    54/W    34/W    43/W
MLS 066 040/058 035/049 033/054 036/051 036/053 037/057
    1/B 42/W    36/W    13/W    34/W    23/W    32/W
4BQ 070 041/059 036/048 030/051 033/049 034/049 034/055
    0/B 33/W    58/W    13/W    24/W    34/W    33/W
BHK 058 035/053 028/046 026/050 030/050 032/051 033/055
    0/E 52/W    22/W    12/W    23/W    33/W    33/W
SHR 068 040/056 036/047 033/052 035/049 034/047 032/050
    1/B 37/T    88/W    24/W    44/W    45/W    33/W




$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.