Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 212103

Area Forecast Discussion
National Weather Service Billings MT
303 PM MDT Wed Mar 21 2018

.SHORT TERM...valid for Thu and Fri...

Billings has reached 50 degrees today...the first time since late

Building upper ridge bringing warmer temperatures today, and the
warming trend will continue tomorrow. Increasing easterly winds
along with large snow field over our eastern cwa will have its
usual cooling affect, but should see 50s to lower 60s along the
foothills on Thursday. Other issue to think about is if
fog/stratus develop/advect into our east late tonight. This could
keep temps cooler tomorrow across our east. NAM seems much too
cool/moist at the surface, as usual, but high res models beginning
to show fog near the Dakotas border by 12z. Have added fog to the
eastern valleys and in Fallon/Carter Counties from 06-18z.

Deep Pacific low will move inland, and shortwave embedded in a
deep moisture plume will bring a good chance of mostly rain and
high elevation snow to our region Thursday afternoon and night.
Have raised pops a bit more over our western mountains, which
should see several inches of snow above 9kft...but snow levels
will remain seasonably high. To the east of deepening surface
trof, easterly winds will increase through the day tomorrow
especially from Baker to Ekalaka. Cannot rule out a slight risk of
mixed precip (i.e. freezing rain) as precip develops in our east
Thursday evening, but current indications suggest precip should
stay rain with temps in the mid-upper 30s. Something to watch over
the next 24 hours. For precip amounts, looks like up to a tenth
to quarter inch in our far northeast.

Shortwave exits to the east by midday Friday, and a somewhat
cooler and more stable airmass will settle over eastern MT. Best
chance of showers Friday afternoon and night will be across our
west. A chilly night w/ a hard freeze is expected across our east
Friday after a period of increased snow melt Thu/Fri,
there should be a long period of sub-freezing temps Friday night.
Will need to keep monitoring streams/rivers for ice jams and
potential low-land flooding.


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

Main concern in the extended (outside of ice jams and snow melt)
is regarding split Pacific trof as it finally kicks through the
central Rockies early next week. Medium range models are in fair
agreement here, but differ in important details. GFS/ECMWF show an
opportunity for ascent from the central Rockies low to lift into
our cwa, especially south central and southeast parts. There is
also a chance that we will stay dominated by a drier westerly
flow with ascent suppressed to our south. At this time, there is
some consensus among models/ensembles tha we will see energy from
the south lifting to our southern cwa, and for potential wet
snowfall over a 12-24 hour period Sunday night and Monday. Upslope
areas on the east side of the Bighorn mountains could see
accumulating snowfall (i.e. Sheridan), as could higher hills
across southeast MT. Still a great deal of uncertainty but
something to keep an eye on. Beyond Monday, looks like drying into
Tuesday then a potential Canadian clipper by midweek, as upper
ridge sets up along the Pacific coast. Temperatures look coolest
Sunday/Monday (highs in upper 30s to mid 40s) followed by what
should be warming by midweek.




VFR conditions will prevail through the TAF period. Patchy fog is
again possible across eastern routes, including KMLS and KBHK, in
the early morning hours Thursday. Otherwise, isolated snow
showers and increasing cloud cover can be expected over the
Beartooth/Absaroka Mountains through overnight. Occasional
mountain obscuration is possible with showers. AAG



    Thu     Fri     Sat     Sun     Mon     Tue     Wed
BIL 032/054 037/052 030/050 029/043 026/043 026/049 029/049
    00/E    32/W    12/W    23/O    43/O    10/U    12/W
LVM 034/060 037/055 031/050 026/043 023/043 023/049 026/050
    14/W    62/W    24/W    23/O    43/O    10/U    12/W
HDN 027/052 034/051 027/051 026/043 023/043 022/048 026/048
    00/E    22/W    12/W    23/O    44/O    10/U    12/W
MLS 025/042 034/043 023/046 026/040 023/039 023/042 026/043
    00/E    43/R    01/B    22/O    23/S    10/U    11/B
4BQ 025/047 036/047 024/053 028/042 024/040 022/044 025/046
    00/E    23/R    01/B    23/O    45/S    20/U    02/W
BHK 022/040 034/041 023/043 028/039 023/038 022/042 024/044
    00/N    64/R    11/B    22/O    23/S    10/U    01/B
SHR 029/058 038/054 028/055 028/043 023/040 021/047 025/047
    00/E    23/W    02/W    24/O    55/S    20/U    02/W




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