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
FXUS65 KBYZ 271524

Area Forecast Discussion
National Weather Service Billings MT
924 AM MDT Thu Oct 27 2016

Dry and very mild conditions on tap for today as we remain under
the influence of strong ridging aloft, with Pacific trof along the
coast. We are seeing quite a bit of high cloud spread over the
high plains ridge, and while this may hold temps back slightly
today, it should be noted that the airmass itself is very warm
with 700mb temps near +9c in our S/SE. This should translate
easily to the 70s and would not be surprised to see places like
Sheridan and Broadus push 80 degrees. This would still be a few
degrees short of record highs for the date. Livingston`s record of
75F seems to be the most achievable of all of our climate sites.
Regarding wind, Livingston has been gapping above 40 mph at times.
Winds should remain quite gusty into the afternoon as mixing taps
into 40+ kt winds in the 850-700mb layer along the western
foothills. Have made some adjustments to sky cover and wind for
today. JKL


.SHORT TERM...valid for Tdy and Fri...

Upper level ridge centered over the forecast area this morning
being overrun by a strong plume of moisture in advance of a
splitting trof along the Pacific Coast. Weak shortwave energy
breaking down the apex of the ridge over Canada today will
maintain downslope pressure gradients while the splitting trough
begins to shift the deeper moisture northward into Canada.
Combination will favor unseasonably warm conditions today
supported by mostly sunny skies.

Combination of factors work to flatten the ridge overnight which
shifts the surface trough eastward and allows the moisture tap
from the orphaned southern part of the trough split to begin
moving back towards the area. Still enough downslope to keep
overnight temperatures mild especially for western areas as clouds
begin to return to the ara.

On Friday a weak front slides through the area from the northwest
but which brings cooler temperatures primarily by cutting off the
downslope low level flow. The moisture increases over the area as
the the southern portion of the trough moves through the Great
Basin and it begins to tap into some moisture from Hurricane
Seymour. Though upper level dynamics are not favorable until
Friday evening for shower activity across the plains the mountains
will begin picking up mainly orographic precipitation by midday
Friday and low level upslope will aid some of these showers
shifting over the western half of the forecast area during the

Arrival of the shortwave Friday evening brings a strong chance for
rain for south central Montana with lesser chances of
precipitation north of the Bull Mountains and over southeast
Montana. This is the area with the best mid level temperature
gradient with mid level winds southwesterly so expect isentropic
lift. This will be aided over the foothills where low level
upslope will continue to play a role so heaviest amounts of
rainfall expected south and west of Billings. Models showing
precipitable waters approaching .75 inches for the area with
saturation from the surface to 500mb so expect the rain fall to be
fairly efficient even if its only over a given area for 6 hours as
the band of favored rain shifts from the foothills north and east
overnight. Snow level primarily above 8000 feet but some
accumulations near 6 inches could be seen in some areas. borsum

.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...

Saturday, low pressure system sliding east will leave some
lingering showers and snow in the high country through the morning
hours, although meaningful accumulations are not expected at this
time. Things clear out for a day or two until the next upper-
level disturbance moves in Sunday night into Monday bringing
another round of wet weather. Pressure gradient tightens as system
moves east of the area on Tuesday. For this reason, keeping an eye
on the trend toward stronger wind gusts from Livingston to Nye.
Near normal temperatures expected through the mid part of next
week. Walsh



VFR will prevail over the area through tonight. Isolated to
scattered showers will move into the region, from KBIL W, Friday morning.
MVFR conditions are possible in the showers over KLVM late Fri.
morning. Expect areas of mountain obscuration beginning tonight
and increasing on Friday. Gusty SW surface winds with gusts to 35
kt will occur over KLVM through this evening. LLWS is possible
overnight in KMLS. Arthur



    Tdy Fri     Sat     Sun     Mon     Tue     Wed
BIL 073 050/059 040/054 041/065 043/055 036/053 034/053
    0/B 02/W    74/W    12/W    53/W    11/B    11/B
LVM 073 048/057 038/055 042/062 039/052 035/053 034/054
    0/N 24/W    74/W    15/W    54/W    11/N    11/B
HDN 077 046/062 040/056 037/067 041/055 034/056 032/054
    0/B 02/W    74/W    11/B    53/W    11/B    11/B
MLS 074 047/062 040/052 038/063 043/052 034/054 029/050
    0/B 01/B    55/W    11/B    43/W    11/B    11/B
4BQ 077 047/065 040/054 039/068 043/054 033/056 029/053
    0/B 01/B    74/W    01/B    23/W    11/B    01/U
BHK 073 045/061 036/049 036/061 040/050 031/052 027/049
    0/B 01/B    46/W    11/B    33/W    11/B    11/U
SHR 077 046/063 037/055 036/067 039/054 030/055 029/055
    0/B 03/W    74/W    11/B    22/W    10/B    11/B




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