886
FXUS65 KBYZ 251952
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
152 PM MDT Sat May 25 2024

.DISCUSSION...

Today through Sunday night...

Today will see precipitation chances and more active weather
return to the region. A couple upper waves will move across the
region creating a low pressure system to the north of us. A weak
cold front will move across the region bringing showers and
thundestorms along and behind it starting around 21Z this
afternoon. CAPE values will be low with values generally below
500J/kg limiting updraft potential. Shear will also be limited
with 0-6km bulk shear values being in the 20-30kt range. Looking
at soundings, there will be speed shear in the atmosphere but
directional shear will be almost nonexistent. The speed shear
could tilt some updrafts and prolong some thunderstorms but
overall thunderstorm potential looks limited. Due to these
factors, the Storm Prediction Center has the region in a general
thunderstorm risk for today. These showers and thunderstorms will
persist through the overnight before exiting into the Dakotas
tomorrow morning. Most locations west of Billings have a 50-80%
chance of getting >0.10 inches of precipitation while locations to
the east have a 20-40% chance. Sunday will see gusty westerly
winds come in behind our system as pressures start to rise. Most
of the region will see wind gusts into the 30s kts throughout the
day. Increasing 700mb winds into the 30s kts and steep low level
lapse rates in the 8-9C/km range leading to efficient mixing will
be the main reasons for this. Most of the region will have a
30-60% chance for a wind gust over 30mph with higher chances for
western gap areas and lower chances for area near the Dakotas
border. Temperatures today and tomorrow will be in the mid 60s to
low 70s fo most. Torgerson


Monday through Saturday...

An upper ridge will build and move eastward over the Northern
Rockies Monday into Monday night. As this pattern evolves,
temperatures aloft will warm and with some downsloping flow will
help to warm surface temperatures to the 60s and 70s.

On Tuesday, upper ridge will move farther eastward so that the
ridge axis will approach the MT/Dakota border. Low-level winds
will turn more south-southeasterly which will facilitate further
warming with high temperatures in the 70s to lower 80s. In the
afternoon and evening, areas west of Billings will be under some
cyclonic southwesterly flow with a 20-40% chance of showers and
thunderstorms in the western mountains and foothills.

With the warming temperatures and recent snowfall in the
mountains, there is concern for snow melt to cause waterways to
run high. Any property and/or recreation on waterways should be
considered during this warm period.

Wednesday, a cold front will cross the area from west to east.
South/southeasterly winds east of the front will encourage
instability over southeast MT with NBM showing a 30% chance of
CAPE reaching 1000 J/kg over far eastern MT. However, shear will
be lacking so not expecting much in the way of severe weather at
this time. There will be isolated-scattered showers and
thunderstorms (20-40% chance) in southeast MT from the front. Then
behind the surface front, an upper air disturbance moving
northeastward over Montana will bring large scale ascent and 700
mb frontogenesis and a 60-90% chance of showers and isolated
thunderstorms to south central MT. NBM shows mean precipitable
water values range from ~0.6 to ~0.9 inches Wednesday evening
with the highest PW values over southeast MT. However, greatest
dynamics are over south central MT. So if a thunderstorm were to
form over southeast MT it could drop some localized heavy
rainfall. Otherwise, over south central MT, NBM shows a 20-50%
chance (greatest in mountains) of receiving at least 0.50 inches
of rain from this system. Snow is also expected Wed. night above
8500 feet with 1-2 inches of accumulation.

Model solutions begin to differ on Thursday with 2 clusters
showing a deeper upper trough over the Pacific Northwest while 2
other clusters place the upper trough more to the north in
western/central Canada. The deeper trough over the PacNW would
mean wetter weather for our area while the more northern placement
and eventual upper ridging would mean drier weather. Given these
differences NBM has a 20-50% chance of showers and thunderstorms
each day Thursday-Saturday. Precipitation should be in the form of
snow above 7500-8500 feet but currently snowfall amounts look light.

High temperatures will generally be in the 70s and 80s Wednesday
then 60s to 70s Thursday through Saturday. TS/RMS

&&

.AVIATION...

Showers and thunderstorms are beginning to make their way into
the region and will continue through the overnight. These storms
are not expected to be severe. Mountain obscurations will be
likely. Winds will be gusty tomorrow with most locations gusting
into the 30s mph. Torgerson

&&

.PRELIMINARY POINT TEMP/POPS...

    Sun     Mon     Tue     Wed     Thu     Fri     Sat
-----------------------------------------------------------
BIL 047/066 044/073 047/080 054/079 049/065 045/067 046/073
    52/R    00/U    00/U    15/T    64/T    33/T    22/T
LVM 040/063 038/071 044/080 051/075 042/060 038/065 041/071
    70/N    00/U    01/U    38/T    65/T    34/T    22/W
HDN 046/067 040/073 044/082 052/081 049/068 044/068 044/075
    74/R    10/U    00/U    14/T    63/W    33/T    22/T
MLS 048/066 045/071 045/080 055/083 051/070 046/069 046/074
    53/R    10/U    00/U    11/B    52/W    32/T    22/W
4BQ 047/066 045/069 046/080 054/085 051/071 046/067 046/074
    44/R    00/U    00/U    01/U    42/W    32/T    22/T
BHK 044/065 042/068 042/077 050/081 050/071 044/067 044/072
    44/R    10/U    00/U    01/U    52/W    32/W    22/W
SHR 041/064 041/069 044/080 051/082 047/068 041/066 041/073
    46/T    10/U    00/U    03/T    53/T    32/T    22/T

&&

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

&&

$$
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