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
FXUS65 KBYZ 161627

Area Forecast Discussion
National Weather Service Billings MT
1027 AM MDT Sun Oct 16 2016


Increased PoP chances from Rosebud County eastward for the next
few hours as light showers ahead of a cold front push eastward
through the Plains. Showers over the Beartooth foothills are
generating gusty winds around 50 mph along the Interstate 90
corridor from Reed Point to Billings. Forecast looks on track for
this afternoon with gusty winds 40 to 50 mph over the foothills
during the early afternoon and potentially stronger gusts at the
Mountain elevations above 6000 feet. Walsh


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

Main forecast concern today is gusty winds. Mid level trof moves
eastward across the area today supported by a 150kt kt jet stream
pushing into Wyoming, and dragging a weak pacific cold front
through the area this morning. Strong pressure falls ahead of the
front around sunrise should be enough to produce 40 to 50 mph wind
gusts over the western foothills...and models hinting at a
moderate mountain wave set up for the eastern Beartooth Foothills
and eastern Bighorn foothills as well. Winds in the mountains
above 6000 feet could reach 70 mph this morning as this mountain
wave develops...with gusts in the 40+ mph range possibly reaching
into the Red Lodge and Sheridan areas before mid day. These
mountain wave features are tough to pin down though so kept wind
speeds below the max potential but well above the normal light
wind conditions common to those areas. Further out into the plains
wind gusts of 30 to 40 mph look to be common along and behind the
front as 850mb cold advection and deep subsidence work to mix and
push stronger winds aloft to the surface. HRRR is hinting at a few
gusts in the 50 mph range around noon so will keep a close eye on
wind trends through the day for potentially stronger gusts.

Precipitation today will be mainly in the morning hours as energy
associated with the upper trof and the surface cold front move
through. West facing mountain slopes continue to see the brunt of
the precipitation with the consistent Pacific flow. Snow levels
continue to stay above 8000 feet so Cooke City has seen mainly
rain the past few days and should continue to today. Across the
lower elevations a couple of bands of light shower activity will
move through but any precipitation is expected to be brief and
light in nature. Should see some significant clearing by mid day
as subsidence builds into the area for a mostly sunny afternoon in
most locations. Temperatures will be mainly in the 60s today but
the gusty winds will make it feel cooler.

Tonight and Monday...The aforementioned jet stream, which extends
way out into the northern pacific south of Alaska, will bring a
period of divergence aloft to the area tonight through Monday as
jet streak tries to break off to the north of the main jet. This
energy combined with a couple of vorticity max will produce
significant lift over northern wyoming this evening that shifts
northward into the area overnight into Monday morning. Biggest
impacts will continue to be in the Mountains with this system
given the continued downslope winds into the lower elevations.
However, the broad lift will provide a better chance for
precipitation in the lower elevations and eastern foothills. Snow
levels drop to around 6000 feet in the western mountains, and
around 7000 feet in the Bighorns late tonight. Expect 4 to 8
inches in the western mountains and 2 to 4 inches in the Bighorns
above those elevations. Cooler air aloft along with showers and
cloud cover will keep temperatures in the 50s for most locations
Monday afternoon. Chambers

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

Made only a few changes to the extended forecast based
on the latest model trends. The models were not in good agreement
toward the end of the period.

A broad shortwave trough will be over the region on Tuesday and
gradually move through the area through Wednesday. Downslope flow
will accompany the trough, keeping precipitation chances generally
low over the plains. There will be just a few inches of snow over
the mountains. Temperatures will be a few degrees below normal.
Upper ridging will become anchored over the region Thursday
through Friday with drier and warmer conditions.

Model disagreement begins on Saturday when the GFS brings
shortwave energy through the region while the ECMWF continues
general ridging. Some moisture will move through the flow on both
models. Since the models kept the area generally dry, have kept
the forecast mainly dry for now. The GFS plunges a cold front
through the area Sat. night with QPF, and has a colder airmass
over the area than the ECMWF for Sunday. Went with slight chance
PoPs for Sat. night and had some Climo QPF over the mountains on
Sunday due to the uncertainty. Went with a model blend for
temperatures on Sunday.

Increased gap flow is possible Thu. through Friday. Arthur



Expect strongest winds across the area through early afternoon
with much of the region seeing gusts of 40 to 50 mph. Shower
activity will be fast moving and impacts will be short lived but
brief MVFR conditions are possible. Mountain obscurations possible
through the period. Expect decreasing winds and clearing skies
this evening. borsum



    Tdy Mon     Tue     Wed     Thu     Fri     Sat
BIL 064 044/057 040/057 038/056 035/058 042/064 042/061
    1/N 04/W    21/B    32/W    11/B    00/B    01/B
LVM 056 038/051 034/051 032/050 032/056 040/061 039/060
    2/W 17/W    23/W    32/W    11/N    01/N    01/N
HDN 066 042/058 039/059 037/057 034/060 038/066 039/062
    2/W 14/W    21/B    22/W    11/U    00/B    01/B
MLS 068 041/060 039/058 036/055 035/059 040/065 042/062
    2/W 03/W    31/B    12/W    11/U    00/B    11/B
4BQ 071 041/061 038/059 036/055 033/061 038/068 040/064
    2/W 03/W    21/B    12/W    11/U    00/U    01/B
BHK 069 038/060 038/056 033/053 031/057 036/063 038/060
    2/W 03/W    31/B    12/W    11/U    10/N    11/B
SHR 065 039/058 034/056 033/054 030/059 035/067 037/062
    3/W 24/W    21/B    22/W    11/U    00/U    01/U




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