Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 272009
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
209 PM MDT Wed Mar 27 2024

.DISCUSSION...
Tonight through Friday night...

Cumulus field has developed over the forecast area this afternoon
under steep lapse rates ranging from 7 to 9 deg C/km. Not
expecting any showers due to downslope flow and large temp/dew
point spreads. Lee trough was in place over the western forecast
area and temps were in the 40s to lower 50s, except in the 30s E
of KMLS due to areas of prolonged low cloud cover and snow on the
ground. Did an update earlier to raise temps central and W, and to
increase gust speeds based on observations.

Upper ridge will move E across much of the area tonight. It will
be dry expect for a 40% chance of snow in the SW mountains. 700 mb
winds at 06Z were progged to be WSW 30-35 kt per the NAEFS.
Surface pressure gradient was not overly strong, and NBM did a
good job of putting in wind gusts of 40-45 mph in the KLVM area.

Ridge moves off to the E on Thursday and forecast area will be
under SW flow with energy in the flow. It will be a prefrontal day
over most of the area with deep mixing and downslope flow over the
central and W. Given the above, have blended NBM high temps with
the 75th percentile, resulting in highs in the 50s to mid 60s.
Kept temps lower in the far W due to frontal timing. Strongest
frontogenesis will be to the N of the area, and QPF will not be
too high with the front, with probabilities showing a 39% chance
of 0.10 in or higher through 06Z Thu. night. KBIL will have a 33%
chance and KSHR a 15% chance. PoPs will spread W to E into
Rosebud County by 00Z Friday and will generally be 50-70% from
KBIL W. Precipitation type will be rain, with snow in the
mountains. Expect gusty SE winds over KBHK and Ekalaka, due to a
tight pressure gradient. Moderate to high PoPs will spread E
through the entire area Thu. evening behind the front, with rain
mixing with snow W of KBIL. KLVM will have a slight chance of a
thunderstorm early Thu. evening. Airmass will dry out late Thu.
night with some lingering PoPs over and near the mountains and
over the far NE zones. Chances of 6 or more inches of snow in the
Beartooths/Absarokas from 12Z Thu.-12Z Friday will be 20-40%.

Cold front will push into the area from the N on Friday bringing
low chances of rain and snow from KBIL-KSHR W. It will be cooler
with highs mainly in the 40s. 20-30% chances of rain and snow
continue Fri. night. Arthur

Saturday through Wednesday...

Unsettled Spring pattern will persist through the extended
period. A shortwave drops in from the northwest and combines wil
energy moving north from a Great Basin system Saturday into
Sunday. Models are squeezing out some decent precipitation with
this pattern, especially the ECMWF ensembles over our southern
zones. There are a good deal of drier solutions within the
ensembles (especiall along and north of a Livingston to Ekalaka
line) but also several higher end precipitation producing
solutions. However the system as its portrayed in the
deterministic models (split flow) shows a good deal of mid level
convergence and downslope northwesterly flow which would advocate
for a drier forecast than what is currently advertised in the
deterministic NBM solution.

Monday looks like a dry day with ridging building overhead and
lasting into Tuesday afternoon. Another system begins to impact
the area sometime in the late Tuesday to mid day Wednesday period
depending on model version. Most ensemble solutions are putting
down precipitation over the forecast area by Wednesday mid-day.

Snow is possible during the overnight and early morning hours with
both of these systems. However daytime temperatures are warm,
especially next week, so not expecting much impact in the lower
elevations. Snow in the mountains will be a positive, adding much
needed water to the current low snowpack. Chambers

&&

.AVIATION...

VFR conditions will prevail through tonight. West to northwest
winds will be gusty through 01z this evening, with gusts 20 to
30kts at times, locally a bit stronger possible. Gusts in the
western foothills around Livingston will increase this evening,
approaching 40 to 45 kts at times through tonight and into
Thursday morning. A few light rain/snow showers are possible in
the Bighorn mountains and foothills this afternoon through 01z.
Additional light shower chanced develop for the western foothills
and mountains before sunrise Thursday. This precipitation activity
should not impact flight categories. Chambers
&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 034/062 032/050 029/043 029/042 025/054 035/064 040/061
    15/R    52/R    34/O    46/S    31/B    01/U    24/R
LVM 035/050 027/048 028/044 027/043 025/052 032/061 036/056
    17/R    53/O    34/O    35/S    21/B    01/U    24/R
HDN 028/064 030/051 027/045 028/043 025/053 030/065 036/063
    14/R    72/R    24/O    47/O    42/S    11/U    24/R
MLS 025/060 030/045 024/040 026/040 025/048 029/060 038/060
    10/B    40/B    13/O    23/O    21/B    01/U    22/R
4BQ 026/064 033/048 027/045 028/041 026/048 030/060 038/061
    01/B    20/B    14/O    35/O    42/S    01/U    22/R
BHK 019/053 026/043 020/039 023/038 023/045 026/057 033/058
    11/B    41/B    13/S    34/S    31/B    01/U    12/R
SHR 027/062 027/047 026/047 026/042 025/047 027/060 033/060
    02/R    43/R    34/O    47/O    62/S    11/U    23/R

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
weather.gov/billings


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