Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 140228

Area Forecast Discussion...Updated
National Weather Service Billings MT
828 PM MDT Tue Mar 13 2018

Upper ridge and dry airmass continued over the forecast area this
evening per water vapor imagery. Chances for overnight and early
morning fog will be confined to the Yellowstone River Valley
around KMLS where humidities will be high. The HRRR hinted at
possible fog in this area as well. Warm advection will bring 850
mb temperatures to +8 degrees C by 12Z Wednesday. These
temperatures will be higher than they were back at 12Z this
morning, and surface temperatures were running higher than this
time last night. Dewpoints were in the 20s this evening. The above
factors supported higher min temperatures than what occurred last
night, and guidance was in good agreement with the min
temperatures. Mostly clear skies will continue through the night
with just some high clouds over the SW part of the area. Only
forecast adjustment was to bring winds more in line with ADJLAV
guidance which had captured the observed easterly component well
this evening. Arthur


.SHORT TERM...valid for Wed and Thu...

The rest of the today will be quiet. There could be some more
localized fog in the east again, mainly in the river valleys.
Given that the snowpack is providing some boundary layer moisture
and then letting temperatures cool off at night cannot rule it
out. Tomorrow an initial wave energy moving through during the
afternoon bringing some snow showers to the mountains, and some
rain to the lower elevations. There will be a bit of a break
during the day Thursday before more energy works into the area,
with a deformation zone beginning to setup from Miles City west.
There is some decent QPF overnight with some areas over a quarter
of an inch. The cold air is in by the time the precip starts, so
this will likely fall as snow, but given the much warmer
temperatures to start with, it is going to be a fairly wet snow.
This will still result in 1 to 2 inches of new snowfall by Friday
morning. Reimer

.LONG TERM...valid for Fri...Sat...Sun...Mon...Tue...

Models have come into alignment on wet snow event Thursday night
through Friday. An upper trough over the western United States
kicks energy out into the midwest Thursday night. This sets up a
prolonged period of diffluence over the forecast area. Cold air
will get pulled down as a surface low deepens over Wyoming, with
850mb temperatures falling to -3c. A deep period of upslope will
develop. Have raised PoPs and snow amounts for Friday. A
significant accumulation of snow is possible with this storm
(mainly over south central Montana and Sheridan county Wyoming)
and will have to keep a close eye on this for potential

The main low moves out of the western United States and slides
into the northern Rockies Saturday night and Sunday. This could
generate another wet snow event. The impacts on this event could
be farther east than the previous one, hitting southeast Montana
harder than south central. Models were still struggling with
timing and placement of the low kicking out, so will keep PoPs
scattered for now. Confidence was growing on temperatures
remaining below normal this weekend, into early next week. TWH


Dry, high pressure aloft will dominate our weather with clear
skies and light winds. Areas of fog is possible for areas from
KBIL east, and will continue until around 18z. Local visibility
will be very poor at times, LIFR to VLIFR, but the fog may not
impact any terminals. AAG



    Wed     Thu     Fri     Sat     Sun     Mon     Tue
BIL 026/049 029/048 029/039 026/044 025/040 024/041 023/044
    00/U    76/R    88/O    31/B    35/O    54/O    11/U
LVM 031/057 034/050 030/043 028/047 027/042 027/043 025/046
    03/W    76/R    56/O    21/B    45/O    43/O    11/U
HDN 020/048 024/048 024/039 023/045 022/040 020/041 017/045
    00/U    53/R    88/O    41/B    34/O    54/O    11/U
MLS 017/040 025/039 023/035 021/037 020/036 019/034 016/037
    00/U    23/J    75/S    31/B    25/S    64/S    21/B
4BQ 023/047 027/049 025/038 024/044 024/037 021/038 018/042
    00/U    33/W    88/O    31/B    26/S    75/S    11/B
BHK 020/042 021/037 022/033 022/038 021/036 018/033 015/037
    00/U    22/J    42/S    11/B    25/S    72/S    11/B
SHR 023/053 032/052 029/041 026/046 025/039 023/041 020/044
    00/U    42/R    88/O    31/B    34/O    54/O    11/U




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