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788
FXUS65 KBYZ 300016
AFDBYZ

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

.UPDATE...

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Severe Thunderstorm Watch has been cancelled for Rosebud and
Big Horn counties. The rest of the watch continued until 9pm MDT.
Still keeping an eye on the cluster of storms moving northeast out
of Johnson Cty Wyoming into E Sheridan Cty and eventually into
Powder River county. Stronger activity lingering over Baker is
diminishing and should not be a threat much longer. Over areas
west of Billings, enhanced radar values are due to bright banding
as freezing levels crash and snow works lower in the atmosphere
creating bigger radar returns, not stronger storms. Chambers
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&&

.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...

Approaching upper level disturbance and Pacific cold front will
bring showers and thunderstorms to the region this afternoon and
evening, with activity expected to begin as early as midday in the
west. All TAF sites are at risk of seeing a thunderstorm (or two)
along with local MVFR/IFR in brief heavy rain and erratic wind
gusts of 35+ knots. A few storms could be severe and produce large
hail and strong wind gusts, especially east of KBIL. Thunderstorm
potential will decrease from west to east in the evening but some
showers will linger overnight producing MVFR conditions at times.
Mountains may be occasionally obscured in rain/snow showers
tonight.

TS POTENTIAL TIMES TODAY:
KBIL: 19-03Z
KLVM: 17-02Z
KMLS: 22-06Z
KSHR: 20-04Z

JKL/STP

&&

.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
    91/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
    91/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
    90/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
    +0/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
    92/B    10/U    00/U    12/T    11/B    32/W    20/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
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MT...Severe Thunderstorm Watch 349 in effect until 9 PM MDT this
      evening FOR ZONES 32-33-36-37.
WY...Severe Thunderstorm Watch 349 in effect until 9 PM MDT this
      evening FOR ZONES 198-199.
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&&

$$
weather.gov/billings