Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 160903

Area Forecast Discussion
National Weather Service Billings MT
303 AM MDT Mon Apr 16 2018

.SHORT TERM...valid for Tdy and Tue...

Be ready for the warmest day yet of 2018 for all but our far
eastern cwa today.

Deep Pacific low along the coast will move slowly inland today and
southwest flow aloft will increase accordingly. There exists a
region of dry air in the eastern Great Basin that is surging
northward, and will spread over our central cwa this afternoon.
00z SLC/LKN raobs showed a deeply mixed and dry boundary layer
extending to 540-580mb, and this is consistent with what model
soundings are showing in our cwa today. 700mb plume to near +7C
will make its way as far north as Sheridan County. Throw in some
pre-frontal heating during the peak heating hours, and we are
looking at temps that should easily climb into the 70s across our
central cwa, with 60s in our west. Eastern areas can expect a
strengthening SE wind and very poor mixing. Baker should see wind
gusts of 40-50 mph and high temps only near 50 degrees. Sheridan
could actually push 80 degrees today if able to mix a gusty S-SW
wind along the eastern slopes of the Bighorns. The record high for
Sheridan is 82 degrees. As for convection, steep mid level lapse
rates will give us the potential for some late day thunderstorms
in west/central parts as a cold front moves in from the west, but
the dry air is a problem. High res model trends seem reasonable in
suggesting the best chance of any thunderstorms across our far
west to north central cwa.

There is a good chance of showers tonight into Tuesday as a
Pacific cold front is overrun by a period of mid and upper level
ascent as southern split of trof moves through the central
Rockies. There is an opportunity for some brief wet snow
accumulation in southern Big Horn and Sheridan Counties early
Tuesday as 850mb temps cool to a little below freezing. Along with
gusty post-frontal NW winds, this will be a dramatic change from
the very warm and dry conditions in Sheridan today. Could see 1-2
inches of snow mainly on the grass, with 3-6 inches over the
Bighorn and Pryor Mountains. Showers along baroclinic zone will
shift east and exit to the Dakotas by late afternoon. Behind this
departing system, we should see some weak diurnal showers develop
under the cold pool aloft in the afternoon. Temps on Tuesday will
be significantly colder than today with highs in the mid 40s to
lower 50s, along with the gusty winds as already mentioned.

Chance of showers will diminish Tuesday evening, but breezy W-NW
winds will continue through Tuesday night across the lower


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

No major changes with the 00Z model guidance in the extended.
Wednesday will see ridging across the area, although there is
some hint of a weak shortwave moving over the ridge and some
showers in east central Montana. Have kept the slight chance PoPs.

The next low pressure system Thursday into Friday is still mainly
to the south of Montana. Nothing has really changed with respect
to the east winds into the area with this system and the GFS is
showing some precip across mainly the southern zones. Have
continued the going PoPs. Temperatures will be cooler than normal
through the end of the work week, generally in the low to mid 50s.

Ridging will start to move into the area for the weekend which
will see temperatures start to warm into the 60s. However this
warmup may not last long as there are some hints by the start to
next week that shortwave passing north of Montana could drag a
weak cold front across the area bringing some precip and cooler
temperatures. Reimer


Expect breezy winds around KMLS through the forecast. Winds will
increase across the rest of southern Montana during the afternoon
as a cold front moves through. Gust up to 25 knots are possible. Showers
and isolated thunderstorms from KBIL west possible from 21z through
03z, with rain and snow showers spreading across the area after
03z. Some of these showers could produce MVFR to IFR conditions.


    Tdy Tue     Wed     Thu     Fri     Sat     Sun
BIL 074 036/050 032/052 032/053 033/053 034/061 035/054
    0/N 65/W    21/B    12/R    22/R    11/U    11/B
LVM 063 030/044 026/049 027/051 030/054 030/061 031/054
    3/T 63/W    21/N    12/R    32/O    11/B    22/O
HDN 075 036/050 031/051 030/053 031/053 032/059 033/055
    0/B 77/W    21/B    02/R    22/O    10/U    11/B
MLS 066 037/047 033/049 030/051 032/051 033/056 033/052
    0/N 37/W    12/R    01/B    22/O    10/U    11/B
4BQ 070 038/046 032/048 029/050 032/048 031/054 032/051
    0/N 26/W    11/B    01/B    24/O    10/U    11/B
BHK 049 031/042 031/045 027/046 030/046 031/050 033/049
    0/N 26/W    22/R    01/B    22/O    10/U    11/B
SHR 077 032/045 029/051 028/053 032/051 031/060 031/056
    0/N 58/W    21/B    02/R    33/O    20/U    11/B




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