Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 281509

Area Forecast Discussion
National Weather Service Billings MT
909 AM MDT Fri Oct 28 2016

Weak Canadian cold front oozing into our cwa with a recent shift
to north winds at Billings, but fairly strong SW winds remain at
Livingston and along the foothills as of 9 am. Have adjusted winds
and temps along the foothills, with current temps at or above
forecast highs after another very mild night. Cold advection will
deepen across the cwa thru the day as Canadian surface ridge
settles in. As for precipitation, showers today will be isolated
to scattered as we await stronger forcing associated with area of
PV which is over central CA. There remains quite a bit of model
spread regarding where greatest frontogenesis will exist tonight
into early Saturday, but overall trend is further north compared
to yesterday`s model runs, and this seems reasonable as energy is
still well upstream and will allow for a northward shift once
Pacific shortwave in north central MT passes. Will examine 12z
runs as they come in today. Overall must continue to stress that
this is a very warm system for late October, and lower elevations
will see just rain. JKL


.SHORT TERM...valid for Tdy and Sat...

Weak frontal boundary across the region currently generating a
few spotty showers over the Beartooths through northeastern
Montana. This front is aiding gap winds through Livingston with
some 50 mph gusts which have finally begun to weaken this morning.
As this front slides southward through the morning a few isolated
showers will develop from the Beartooths through Billings and eastward
to Miles City during the day. Upper-level impulse moves closer by
late afternoon. Upper impulse interacts with stalled surface
boundary and produces widespread shower activity which spreads
across the region from southwest to northeast during the early
evening hours on Friday.

Fringe of the rain shield appears to set-up somewhere near the
Billings area through the night so not completely sold on some of
the higher rainfall totals that have been advertised by ECMWF. Will
keep values between 0.25-0.50 inches through Saturday. This value
is much closer to the SREF means, NAM, and ARW models.

Rain will change over to snow generally above 8500 feet Friday
evening. Adjusted snowfall amounts up slightly over the Bighorns
to the 4-6 inch range. QPF amounts could support values above
that, but given the tropical nature of the system have kept snow
ratios and totals lower and more in line with HPC`s forecast.
Colder air makes it`s way into the Beartooths a little earlier on
Friday night which will increase totals to 6 to 10 inches along
the highest peaks.

Colder air filters in on Saturday morning and a dusting or
rain/snow mix is possible along the foothills and areas from
Harlowton to Columbus. Anticipating highs to only reach the low
50s on Saturday. Walsh

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

Overall, southwest flow will prevail over the area with several
shortwaves shifting through. The first shortwave is expected
Sunday night into Monday with the second wave Tuesday into Tuesday
night. The first system does appear to the be the strongest of the
two and gives the best chance of moisture. Both systems will
provide a quick shot of accumulating snow in the high country.
Lower elevations should be warm enough to pick up rainfall with
temperatures remaining above seasonal averages. Raised PoPs for
Sunday night and Monday over the west with the first piece of
energy sliding in. Model disagreement increases from Wednesday and
beyond and did not make many changes to these periods because of
such. TWH



Gusty southwest winds at KLVM will decrease by midday as a
Canadian cold front works through the area. Ceilings will
gradually decrease thru the day as a system approaches from the
southwest. Mountains will become obscured, and lower elevations
will see flight categories reduce to MVFR-IFR tonight into
Saturday morning as precipitation becomes widespread. Expect rain
at lower elevations and snow over the high country with this
system. JKL



    Tdy Sat     Sun     Mon     Tue     Wed     Thu
BIL 061 041/052 041/064 044/057 038/056 036/058 038/060
    3/W 72/W    12/W    55/W    11/B    01/U    00/B
LVM 061 038/053 042/061 041/055 036/055 034/057 037/059
    5/W 72/W    24/W    66/W    11/B    11/U    10/B
HDN 063 040/054 037/066 042/059 036/059 033/060 034/061
    3/W 73/W    11/B    44/W    11/B    01/U    00/U
MLS 062 039/051 039/064 044/055 036/058 034/058 034/060
    2/W 32/W    11/B    44/W    10/B    00/U    00/U
4BQ 067 040/052 039/068 044/059 035/059 033/061 035/064
    2/W 85/W    11/U    44/W    11/B    00/B    01/U
BHK 062 036/048 035/060 041/053 033/057 032/058 032/060
    1/E 32/W    00/B    44/W    11/U    00/B    01/U
SHR 065 038/052 036/065 039/058 032/058 029/060 032/062
    3/W 85/W    01/B    44/W    10/B    10/B    01/B




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