925
FXUS65 KBYZ 300227
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
827 PM MDT Wed May 29 2024

.UPDATE...

Cancelled all remaining counties from the Severe Thunderstorm
Watch. Area has been worked over pretty good at this point and
remaining convection moving NE over SE MT has not shown much
impetus to upscale into something strong. Upper wave and surface
front are moving through West and Central zones at this time with
a broad area of light to moderate precipitation accompanying them.
Radar showing .25 to .5 inch per hour precipitation estimates with
this activity. The stronger returns are from radar bright banding
which may be biasing the radar estimates a bit higher than
reality, but still good rainfall left to move across the area
through late tonight. Updated short term forecast for the latest
thinking, and removed mention of strong to severer thunderstorms.
Dual-Pol radar data is estimating the snow level around 7200 feet
over western zones this evening. Expect 3 to 6 inches over the
western mountains tonight. May see a dusting to an inch over the
Bozeman Pass, with the heavier 3 to 6 inches falling over the
upper reaches of the Beartooth Pass. Bighorn mountains are looking
at generally an inch or less tonight. Chambers

&&

.DISCUSSION...

Today through Thursday night...

Showers and thunderstorms are becoming more numerous this
afternoon due to a front moving across the area and above average
moisture, with PWATs around 0.75-1 inch. The SPC has from
Yellowstone county east under a slight risk for severe
thunderstorms, and the remainder of the area under a marginal risk
today. Additionally, the WPC has the region under a marginal risk
for excessive rainfall due to locally heavy rainfall possible
with storms. The main threat expected from thunderstorms today is
strong winds, with secondary threats of hail and heavy rain.

0-6 km mean wind suggests storms associated with the front will
generally track northeast through the evening. The highest CAPE
values, up to 1500-2000 J/kg, are still expected over the east.
Over western and central areas, CAPE values around 600-1200 J/kg
are expected. In contrast, the highest Shear is expected over the
western and central areas, up to 50-70 kts, and lower values
closer to 30-40 kts are expected over the east. As a result, over
the east, mostly multicell storm clusters are expected while
western and central zones may see faster moving, longer tracked
storms.

Overnight into Thursday afternoon, showers and thunderstorms will
greatly decrease, mostly lingering over the mountains and
foothills with a 30-40% chance. By Thursday morning, snow levels
are expected to fall to around 6000 ft over the
Beartooth/Absarokas. Currently, several inches of snow (6-8" over
the highest peaks) are possible over the mountains, with a 40-50%
chance of at least 4 inches. Archer

Friday through Wednesday...

Unsettled weather can be expected into early next week as
multiple shortwaves are progged to move through the region at
times bringing chances for showers/thunderstorms. A weak wave
exiting the region on Friday will bring low chances (15-25%) for
showers and thunderstorms to far southeast MT. Shortwave ridging
builds into the region on Saturday, before a Pacific wave is
progged to move in from the west Saturday night into Sunday
bringing more shower/thunderstorm chances (20-60% chance,
greatest along the western foothills/mountains). Another period of
shortwave ridging is forecast for Monday, before another, but
potentially stronger Pacific wave moves in from the west Monday
evening, bringing additional shower and thunderstorm chances into
Tuesday (20-60% chance, greatest over central and western areas).
Looking towards the middle to latter portions of the week,
ensembles are in good agreement in ridging and higher heights over
the region. Depending on the exact location of the ridge, we could see some
hotter days (see CPC`s 6-10 and 8-14 day outlooks), but a ridge
axis to our west would keep our area prone to backdoor cooling
periods even with the high heights.

High temperatures are currently forecast to range from the 60s to
lower 70s on Friday, warming into the 70s and lower 80s over the
weekend. Highs in the 70s and 80s are forecast Monday through
Wednesday, with Monday currently the warmest (middle 80s over the
east). STP

&&

.AVIATION...

Cold front is moving through central and western zones this
evening, and will push through SE Montana in the early morning
hours. Areas of showers and isolated thunderstorms will accompany
the front through the area. Expect local MVFR conditions in the
vicinity of precipitation areas. Snow level has fallen to around
7200 feet MSL over areas west of Billings based on dual-pol radar
data at 8pm MDT. Expect the snow level to drop to around 5500 feet
by sunrise. Expect mountain and pass obscurations to continue
through mid morning Thursday, especially over the
Crazy/Beartooth/Absaroka mountains. Outside of precipitation areas
and the mountains, VFR conditions will prevail tonight. Chambers
&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 045/063 043/070 045/079 052/075 054/083 055/074 052/081
    81/N    00/U    00/U    33/T    11/B    43/W    11/U
LVM 038/060 036/068 041/078 049/074 051/078 050/070 048/078
    71/N    00/U    01/B    44/T    13/T    53/W    11/N
HDN 045/064 042/070 043/082 051/077 052/086 055/076 050/083
    91/B    00/U    00/U    32/T    11/B    43/W    20/U
MLS 048/064 041/069 043/082 054/077 054/086 056/075 051/080
    70/N    01/B    00/U    21/B    11/B    32/W    10/U
4BQ 048/064 042/069 044/082 053/077 054/087 057/076 052/080
    90/U    11/B    00/U    11/B    10/B    22/W    10/U
BHK 045/064 039/067 041/079 052/077 050/084 054/075 047/078
    90/N    01/B    00/U    12/W    11/B    32/W    10/U
SHR 042/061 038/069 042/082 050/076 050/086 053/076 048/081
    81/B    10/U    00/U    12/T    11/B    32/W    20/U

&&

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

&&

$$
weather.gov/billings