Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 032108

Area Forecast Discussion
National Weather Service Billings MT
308 PM MDT Fri Apr 3 2020

Tonight through Saturday night...

Satellite imagery and upper air analyses show a large upper low
over southwest Canada with below normal heights extending through
the northern Rockies and high plains. A shortwave is rotating
southeastward through southern BC. Ahead of this energy, and in a
region of steep lapse rates, we have seen scattered snow/rain
showers develop over our western mountains and foothills this
afternoon. Web cams suggest rapidly fluctuating visibility with
the snow showers, so a heads up if you are traveling on I-90 from
Livingston to Bozeman, or US-191 from Big Timber northward through
Judith Gap, over the next few hours.

Ascent from upstream shortwave, along with the instability, will
allow some snow showers to persist thru the night mainly
northwest of Billings. For the most part these should remain
insignificant, but could produce brief/local snow accumulation.
The Crazy Mountains will likely see a couple inches. By early
Saturday, shortwave will slide across northern MT, perhaps
allowing some light showers or flurries to spread east of Roundup
briefly. After the wave passes, subsidence will bring dry weather
through the remainder of the day, with a breezy northwest wind
developing across our east.

Deepening trof along the Pacific coast will kick a weakened
shortwave thru the northern great basin late Saturday night,
perhaps bringing a little light snow to our western mountains.

Forecast lows for tonight are tricky given the spotty snow cover.
Have dropped lows a few degrees in parts of our east and the
Sheridan area (should see teens). Warming trend will continue
tomorrow with temps getting to the mid 40s to low 50s most places.


Sunday through Friday...

Warming trend Sunday and Monday with a bit of a pattern shift on
Tuesday. Sunday and Monday will have southwesterly flow aloft as
the region is between ridging over the central US and an upper low
along the northern California coast. The southwest flow aloft
brings some shower activity mainly to the mountains but for
Monday afternoon the airmass looks a bit more unstable so lower
elevations near and west of Billings could see a shower or even a

By Tuesday an upper low forming over northern Alberta delivers a
shift to a northwest flow aloft but this is actually a shift to a
drier pattern as moisture from the CA low is cut off. Looks like
a cold front will slide across the area Tuesday night with little
to no precipitation ahead of or behind it. The northwest flow
aloft brings high pressure into Montana for Tuesday night and
Wednesday which produces weak mixing and cuts temperatures a few

For Thursday, high pressure will move eastward to south central
Canada and the north central US, which will provide a south-
southeasterly flow in the lower levels of the atmosphere and
warming temperatures over our area.

A cold front is progged to move southeastward over the area
sometime in the Thursday night-Friday timeframe but uncertainty
remains with the timing of the frontal passage. This front could
lower temperatures by 10 degrees or so from Thursday`s expected
high temperatures and bring another round of snow to the
mountains and rain and snow showers to the lower elevations.



Isolated to scattered snow showers will produce occasional
mountain obscurations and brief MVFR conditions at lower
elevations late this afternoon and tonight west of KBIL-KRPX.
Otherwise, VFR will prevail tonight and Saturday. KLVM will see
periodic gusts of 20-30 kts tonight. JKL



    Sat     Sun     Mon     Tue     Wed     Thu     Fri
BIL 028/051 028/056 034/061 038/064 035/058 035/066 039/057
    00/U    00/B    02/T    21/B    11/B    11/U    23/R
LVM 027/050 027/053 034/055 037/058 035/058 035/062 037/054
    21/B    11/B    26/T    21/N    11/B    11/U    23/O
HDN 021/051 025/057 031/063 036/064 034/059 033/067 037/058
    00/U    01/B    02/T    21/B    11/B    11/U    33/R
MLS 019/049 026/055 030/059 035/060 032/055 031/062 035/057
    01/M    01/B    00/E    11/B    10/U    11/U    22/R
4BQ 019/049 025/055 029/064 036/061 033/055 030/063 035/058
    00/U    01/B    00/E    11/B    10/B    01/U    22/R
BHK 018/048 023/050 028/055 033/057 029/052 027/058 033/055
    00/U    01/B    00/E    10/B    00/U    01/U    22/R
SHR 016/049 024/056 031/063 034/061 033/056 031/063 035/056
    00/U    00/B    00/B    11/B    11/B    11/U    23/R




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