Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 190346

Area Forecast Discussion...Updated
National Weather Service Billings MT
846 PM MST Sat Feb 18 2017


Southwest flow aloft with a good deal of moisture embedded will
bring periods of snow to the mountains and mostly cloudy skies to
the lower elevations tonight. Can`t rule out a few sprinkles in
the lower elevations tonight but not enough threat of
precipitation east of the divide to add pops to the zones. Snow
accumulations in the higher terrain will continue to be light with
lift being shallow and orographic in nature. Overall going forecast
in good shape. Chambers


.SHORT TERM...valid for Sun and Mon...

Stream of Pacific moisture continues to infiltrate the inter-
mountain region producing rain and snow showers over our
Absaroka/Beartooth ranges. This precipitation is generally
orographic in nature, but there is some weak impulses to aid lift
at times. Nothing heavy is expected but will keep PoP`s relatively
high at times through the short term period.

Chance of showers will increase on Sunday as northern portion of
split trof approaches from the west. Would expect some showers
with passage of mid level front in the afternoon and evening,
though limited by downslope winds. Better chance of rain will be
in our east overnight as trof lifts to the northeast, offering a
period of stronger ascent and deeper moisture closer to the
Dakota borders. Have left PoP`s as likely from Baker to Alzada
late Sunday night. Temps should stay too warm for much if any snow
accumulation in our east, even over the higher hills. Should see
a little snow accumulation over the Bighorn Mountains Sunday night
as wave passes and mid level winds turn to the NW.

Monday, trof axis exits to the east and we see some weak ridge
building over our CWA. There is still a weak stream of moisture
from the SW affecting our mountains which will continue into
Monday night. Lee-side pressure falls will lead to an increasing
pressure gradient across our foothills. Gusts above 50 mph are
likely in the usual Livingston to Big Timber corridor. We will
need to monitor for a possible wind advisory. Current local
algorithms have about a 45% probability of reaching advisory
criteria (>=58 mph) near Livingston Monday.

Above normal temps will continue into Monday with highs in the
upper 40s and 50s, along with relatively mild nights. BT

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

The main weather feature continues to be the possible winter
storm across southern Montana/northern Wyoming late Wednesday into
Friday. Some disagreement among models continues with the
placement and precipitation amounts. Models have been trending a
bit further south with the storm across eastern Wyoming into
western South Dakota. However, both the GFS and ECMWF are
consistent with keeping the northern most end of the heaviest
precip across the southern portions of Big Horn, Powder River and
Carter Counties southward into northern Wyoming. Given low
confidence with the models, no significant changes were made to
the extended forecast. We are still looking at the likelihood of
snow along and south of a Livingston-Billings- Broadus-Ekalaka
line but the event is a ways out for exact amounts at this time.

After a very warm day Tuesday with many areas in the lower to
possibly middle 60s, temperatures will begin a downward trend
Wednesday with readings in the upper 40s to lower 50s, then below
normal readings expected Thursday and Friday with 30s common.



Southwesterly Pacific flow will keep periods of snow in place over
the mountains resulting in frequent mountain obscuration. VFR
ceilings can be expected elsewhere through Sunday morning. Not
completely out of the question for some patchy fog around sunrise
in the MLS vicinity. Chambers



    Sun     Mon     Tue     Wed     Thu     Fri     Sat
BIL 037/058 034/057 040/064 034/050 027/037 020/034 018/034
    01/E    30/B    12/W    11/B    66/S    32/S    22/S
LVM 035/052 030/052 039/055 031/044 021/034 014/031 013/032
    12/W    22/W    24/W    24/W    66/S    33/S    32/S
HDN 030/054 030/055 036/063 031/049 025/038 020/035 016/034
    01/E    30/B    12/W    11/B    66/S    32/S    22/S
MLS 030/052 033/054 035/060 033/049 026/037 021/034 019/034
    00/B    41/B    12/W    11/B    24/S    22/S    12/S
4BQ 033/058 033/056 035/066 034/051 026/038 018/033 015/033
    00/B    50/B    01/B    10/B    68/S    42/S    13/S
BHK 031/054 035/052 034/061 033/048 025/034 018/031 015/031
    00/B    62/W    02/W    10/B    24/S    31/E    12/S
SHR 033/056 029/055 035/065 032/047 023/033 016/031 011/031
    00/B    40/U    01/B    13/W    88/S    43/S    13/S




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