Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 241547

Area Forecast Discussion...Updated
National Weather Service Billings MT
947 AM MDT Sun Sep 24 2017


Patchy areas of locally dense fog over central zones this morning,
particularly along the Musselshell river valley. This should
dissipate/lift over the next hour or so. Low clouds over central
and western zones will likewise break up as we go through the day,
though cumulus development in areas that do break out will prevent
mostly sunny conditions in most locations. Cloudy and drizzly
conditions can be expected east of a Forsyth to Sheridan line
today. Very weak ascent is probably not enough to produce much
measurable rainfall in this area, but periods of drizzle will keep
the ground wet this afternoon. Stronger forcing moves in from the
south this evening for a better shot at accumulating rain tonight
in these areas. Where we do see some sun this afternoon
temperatures will push into the mid 50s, otherwise 40s look
reasonable for high temperatures today in most locations. Chambers


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

We have an unusual difference in model solutions that has
developed for the short term forecast. The GFS proggs are on the
dry side this morning over our eastern sections. Other models keep
the precipitation coming this morning. 00Z run of the GFS seems
like the odd man out and with the cyclonic pattern and jet
placement as it is on satellite, we will side with the wetter
solutions today.

That said...central Rockies upper low will continue to dominate
our weather pattern over the next couple of days as it slowly
shifts northeast and fills in. Best chance for precipitation will
be today east of a Miles City to Sheridan line as stronger jet
dynamics slice across the region. Most of the precipitation may be
on the lighter side by this afternoon as lapse rates will not be
quite as steep as recent days, but some narrow bands or pockets of
moderate rain are still possible due to the jet dynamics aloft.

Despite upper low shifting through to the northeast we will still
be in a cyclonic pattern with increasing northwest flow in the mid
levels by the latter part of Monday. This means we will be slow to
warm up to seasonal norms until later in the work week. BT

The Winter Weather Advisory for the Bighorn mountains continues,
mainly above 7500 feet through tomorrow. Otherwise any snow
accumulations will amount to a dusting in the foothills or higher
ridges. BT

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

An upper low can produce isolated showers over far eastern MT
Tuesday morning. Forcing is very weak so any rainfall would be
light. Then as this low moves northeastward into North Dakota, E
MT will have a dry afternoon. Northwest flow behind the upper low
can bring a few showers to the higher terrain in the afternoon
mainly west and north of Harlowton.

The rest of the extended period looks mild and dry as an upper
ridge builds in from the west and dominates our weather. High
temperatures will generally be in the 60s Tuesday through Thursday
and then reach the lower 70s Friday and Saturday. RMS



Patchy fog and lower cigs producing LIFR to MVFR conditions this
morning will gradually burn off and lift with MVFR to VFR
conditions expected across western and central areas by the
afternoon. Showers and light drizzle will remain possible today,
generally east of a KBIL to KSHR line where IFR to MVFR conditions
look to continue. Mountain obscurations can be expected. STP



    Tdy Mon     Tue     Wed     Thu     Fri     Sat
BIL 052 038/058 039/065 044/066 044/068 044/070 046/071
    1/B 11/B    01/B    11/B    11/U    00/U    00/U
LVM 052 030/058 035/063 035/065 037/066 037/070 040/069
    1/B 11/U    01/B    11/B    10/U    00/U    00/N
HDN 052 038/057 037/067 042/068 042/070 042/072 043/072
    2/R 22/W    11/B    11/B    11/U    00/U    00/U
MLS 051 040/054 039/065 042/069 045/068 044/071 045/072
    3/R 22/W    21/B    00/U    11/U    00/U    00/U
4BQ 047 040/052 038/063 040/067 042/067 042/069 044/070
    3/R 35/W    21/B    11/U    11/U    00/U    00/U
BHK 049 039/052 039/061 040/067 042/067 040/067 043/069
    3/R 23/W    22/W    00/U    10/U    00/U    00/U
SHR 045 036/052 035/062 037/064 037/067 039/069 041/069
    3/R 43/W    21/B    11/B    11/U    10/U    00/U




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