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000
FXUS65 KBYZ 210806
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
206 AM MDT Sun Apr 21 2024

.DISCUSSION...

Today through Monday night...

Ridging over the area for the first part of the day will flatten
this afternoon as a strong upper low moves across southern Canada.
850mb temperatures rising to around 15c will lead to highs in the
mid to upper 60s. Abundant sunshine (aided by precipitable water
values below 0.50) will lead to humidity falling into the teens to
mid 20s in the afternoon. Winds are not expected to be that
strong ahead of a cold front, with 10-20mph most places. A cold
front arrives in the evening and snaps the wind direction to the
northwest and north, with some gusts 25-35mph. A line of showers
will develop along and behind the front, developing over western
and central zones late afternoon, moving east into southeast
Montana overnight. GFS was putting down a tenth of an inch of QPF
over parts of the southeast zones overnight. Instability is
limited with capes 100-300j/kg, so will keep any lightning near
the slopes were cape is progged the highest.

The deep upper low over southern Canada drops southeast into
northern North Dakota by Monday afternoon. This will bring a dry
slot across the forecast area in the early afternoon with humidity
falling into the teens to lower 20s. 850mb winds increase to
30-40kts (strongest over the east). NBM has a 65% probability of
Baker hitting 40+mph gusts with a 25% chance at Miles City.
Billings will be gusty too, but 850mb winds were weaker over
central and western zones, but there is still a 30% chance of
gusts of 30+mph at Billings Monday afternoon. Temperatures will be
cooler than Sunday (about 5-10 degrees) with highs in the mid 50s
to around 60 degrees (which is seasonal). Minimum humidities are
progged to stay above 20 percent in the east (where the winds will
be the strongest). That and the fact that temperatures will be
cooler (highs only in the mid 50s at Baker) leads to holding off
on any fire weather highlights for Monday. Will brief the day crew
about a potential Rangeland Fire Danger Statement for Monday over
the east, but overnight showers and cooler temperatures could
greatly inhibit that. Winds decrease Monday night. TWH

Tuesday through Sunday...

An active weather pattern is shaping up next week. Be sure to
monitor the forecast over the coming days.

Tuesday through Wednesday morning will see the quietest weather
of the week as upper ridging moves across the region. Temperatures
will respond accordingly, with highs in the upper 50s to lower
60s Tuesday and lower to mid 70s Wednesday. By Wednesday
afternoon, we could see showers move back into the west as upper
level flow backs to the SW, allowing Pacific moisture and
shortwave energy to move in (20-60% chance, highest over the
mountains). This will kick off the start of a potentially active
second half of the week and weekend.

On Thursday, a developing trough along the west coast will
contribute to height falls and more unstable weather developing
across our area. At this time, the NBM has a 15-80% chance for
precipitation Thursday, with the highest chances over the
mountains and foothills and lowest chances north and east of
Billings. This precipitation will be aided by increased
precipitable water values streaming in from the Gulf of Mexico, so
heavy rain with a few thunderstorms is not out of the question.
Outside of precipitation, Thursday will still be warm with highs
generally in the upper 60s to lower 70s, but this will mark the
beginning of a cooling trend for temperatures back near to
slightly below normal for Friday into the weekend (normal is mid
to upper 50s).

Periods of wet, unsettled weather will likely continue Friday
through at least Sunday (25-80% chance for precipitation, once
again highest over the mountains and foothills and lowest over
Custer and Fallon Counties). Unfortunately, the exact when and
where of precipitation is still uncertain. Cluster analysis shows
a lot of the uncertainty lies in the development of the organized
upper low projected to form over the west this weekend. A more
organized and north low would provide more precipitation to the
region, whereas a split or south low would provide less. If the
significant precipitation does materialize, we are still looking
at mid level temperatures cooling enough for higher elevation snow
instead of the more problematic rain-on-snow scenario. Arends

&&

.AVIATION...

VFR conditions will prevail today as clouds increase from the
west. These clouds will be associated with a cold front that will
move through from west to east late this afternoon into this
evening, between 23Z and 06Z. This front will bring a wind shift
from S/SW to N/NW with wind gusts in the 15 to 30 kt range. Along
with the winds, scattered showers look to accompany the front,
potentially impacting all TAF sites. While the chance for a
thunderstorm remains low, we could see a thunderstorm or two
develop off the Beartooth/Absarokas this afternoon/evening,
potentially bringing a vicinity thunderstorm to KLVM and KBIL.
Arends

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Mon     Tue     Wed     Thu     Fri     Sat
-------------------------------------------------------
BIL 068 037/060 034/062 039/074 047/069 046/061 043/058
    1/B 50/N    00/U    01/B    25/T    34/R    36/R
LVM 066 030/057 029/061 038/071 043/065 040/054 039/052
    2/W 20/N    00/B    03/R    36/T    45/R    46/R
HDN 071 036/061 032/065 037/077 045/071 045/065 042/061
    1/B 60/N    00/U    01/B    34/R    33/R    35/R
MLS 068 038/059 035/060 039/073 046/071 046/065 042/061
    0/U 40/N    00/U    00/B    12/R    22/R    12/R
4BQ 069 039/058 035/061 040/075 046/072 047/062 042/061
    0/U 41/N    00/U    00/B    12/R    33/R    23/R
BHK 065 036/056 032/057 035/070 042/070 043/061 038/060
    0/U 31/N    00/B    00/U    13/R    22/R    12/R
SHR 067 034/058 031/061 036/074 043/068 042/059 038/057
    0/U 51/N    00/U    01/B    25/T    55/R    46/R

&&

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

&&

$$
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