Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 271534

Area Forecast Discussion...Updated
National Weather Service Billings MT
934 AM MDT Mon Mar 27 2017

Weak energy working through central zones this morning producing
a few weak showers east of Billings. Have added low PoPs in to
cover these hanging around a little longer than expected. Other
than that and accounting for cloud cover, current forecast in good
shape with no other changes. TWH


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

Water vapor imagery shows weak shortwave lifting through the area
in SW flow aloft. There are some modest echoes showing up on BLX
radar to the northeast of Billings, i.e. east of surface trof.
Cloud bases are high enough such that this is likely virga or
perhaps sprinkles, but have added an isolated early morning pop.
Otherwise, our attention then turns to deeper Pacific trof which
will dig thru the Great Basin toward the 4-Corners over the next
24 hours.

Instability along inverted trof east of Billings could be a focus
of isolated showers this afternoon as daytime heating allows for
up to 100-200 j/kg of cape. Have expanded afternoon pops east to
cover this. Greater coverage of showers, of course, will be to our
west as ascent from trof and a surface cold front move in during
the late afternoon and evening. A good chance of showers exists
from west to east across the cwa tonight and Tuesday with this
trof passage, and eastern areas will be aided by a weak
circulation lifting thru WY tomorrow. Rainfall of a quarter to
half inch is expected at Sheridan and across far SE MT. Though
this system is not overly dynamic, the combination of fairly steep
mid level lapse rates and deep/moist upslope flow should yield
several inches of snow over the Bighorn Mountains. Have issued a
winter wx advisory for 5-10 inches of snow in the Bighorns from
this evening to Tuesday evening. Most lower elevations will stay
as rain, but foothill locations as low as 4500 feet could mix with
wet snow late tonight into tomorrow morning. Surface temps should
stay warm enough to prevent any real travel impacts, but reduced
visibility could occur on I-90 near Livingston and over Aberdeen
Hill toward Sheridan. Places like Red Lodge and Story could see a
little slushy accumulation.

System will track east and drying will spread in from the west
Tuesday afternoon and night.

Temperatures will be well above normal today with highs in the
upper 50s to mid 60s most places. Tuesday will be cooler of
course, with highs in the mid 40s to mid 50s, coolest down toward
Sheridan. JKL

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

Wednesday will generally be warm and dry as the area is under
ridging. Going into Thursday things will change to colder and
wetter again as the next low moves into the Intermountain West.
The GFS has continued its trend towards a wetter solution similar
to the ECMWF runs the past several days. The EC on the other hand
is taking the low farther to the southwest, with some energy
breaking off the main wave and cutting across northern Montana.
This results in less upslope into the mountains. While there would
be some precip with this solution, it would not have many
impacts. The GFS solution keeps the energy with the main wave and
places the low with better diffluent flow over southern Montana.
This solution has a better potential for some accumulating
snowfall in the mountains. Have continued to trend temps down for
Friday with the rainfall, closer to the raw consensus. For PoPs
have leaned more towards the GFS solution given that it is the
more consisten solution.

Going into the weekend things will be drying out with more
ridging across the area. Temperatures will warm back up upper 50s
to middle 60s. Early next week models have high variability so
have just gone with a blend of solutions. Reimer



VFR conditions will continue today. A few weak showers will
linger around KMLS this morning. A disturbance will work through
the area this afternoon and tonight, bringing scattered showers.
The best chance of showers will be west of KBIL and impact the
mountains and KLVM. Flying conditions will lower to MVFR over the
west tonight as these showers move in and the mountains will
become totally obscured. The mountains will pick up a shot of
steady snow tonight into early Tuesday. TWH



    Tdy Tue     Wed     Thu     Fri     Sat     Sun
BIL 062 041/055 035/063 041/058 040/050 034/059 038/060
    2/W 66/W    11/B    14/R    66/R    21/B    11/B
LVM 055 032/054 029/060 038/051 033/049 030/059 034/061
    5/W 83/W    11/N    26/R    75/O    21/B    12/W
HDN 064 039/053 032/064 038/061 039/051 033/060 035/062
    2/W 56/W    10/U    13/R    56/R    21/U    11/B
MLS 065 041/056 036/064 040/063 042/053 035/060 038/063
    2/W 26/W    40/B    12/R    44/R    21/B    01/B
4BQ 065 041/050 035/062 038/063 041/052 034/057 036/061
    2/W 37/W    61/B    01/B    45/R    31/B    11/B
BHK 062 037/055 036/061 037/062 039/053 033/056 034/060
    1/B 26/W    61/B    11/B    33/R    20/B    11/B
SHR 061 035/046 030/058 034/059 038/048 031/056 034/059
    1/B 68/W    20/U    13/R    66/R    31/B    10/B


WY...Winter Weather Advisory in effect from 6 PM this evening to 9
      PM MDT Tuesday FOR ZONE 98.


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