463
FXUS65 KBYZ 112024
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
224 PM MDT Tue Jun 11 2024

.DISCUSSION...

Today through Wednesday night...

For today, 500 mb analysis is showing ridging building in the area
providing warm and dry conditions. High temperatures will be in
the 80s today. Into this evening, energy moving across northern MT
will increase precip chances for the region (20-50% chance).
Scattered showers with a few embedded thunderstorms will begin to
develop late afternoon over the western foothills. They will track
northeast through the night with a 20-50% chance for much of the
region. Any thunderstorms that do develop will be weak with MUCAPE
values generally remaining below 500 J/kg. Better chances for a
thunderstorm will be over the mountains with MUCAPE values closer
to 1000 J/kg. Into Wednesday, tight westerly flow and resulting
downsloping will keep the region dry and breezy. Wind gusts will
be highest along the western foothills and along the northern and
eastern borders of the region. 700 mb winds of 35-45 mph over
these locations do have the potential to mix down during the
afternoon. Across the central zones, gusts will generally be in
the 20s (mph). Winds will die down around sunset. RH values will
be low, generally 15-20% Billings north. Highs Wednesday will be
in the upper 70s to mid 80s.

The Flood Advisory for the Beartooths and adjacent foothills has
been canceled. With local gauges showing river/stream heights
slowly declining, the concern for minor flooding has greatly
decreased. TS

Thursday through Tuesday...

The extended period will begin quiet, as flat upper level ridge
builds back over the region on Thursday, with winds becoming
easterly (and much lighter than Wednesday). This quiet period will
persist through early Friday. Ridge axis shifting to our east will
allow for warmer air to advect from the southwest on Friday. Thus,
after seasonable temps on Thursday, we should see mid 80s to near
90F on Friday (consistent w/ 700mb temps near +12C). This would
also make it the first touch of 90F in 2024.

Weak energy in the southwest flow will bring a good (30-50%)
chance of afternoon and evening thunderstorms on Friday. The warm
mid levels and steep lapse rates are suggestive of a wind risk,
but low level moisture advection in our east may push dewpts close
to 60F resulting in LIs near -4C. The GEFS shows a 20-30% of
CAPEs reaching 2000 j/kg in Fallon/Carter, with enough bulk shear
(30-40kts) to support severe storms capable of producing large
hail along with strong winds. A heads up for those with travel or
outdoor plans that Friday is a day to monitor for potential strong
to severe thunderstorms.

We remain in a southwest flow regime on Saturday as a low deepens
over the PacNW. Given this is a post-frontal day there is
considerable model uncertainty in temps and instability. Western
areas could/should be cooler and more stable, but the east may see
700mb temps surge to as high as +14C. There is a 20-30% chance of
diurnal thunderstorms on Saturday, but indications are that our
east has the higher chances, and again maybe a severe risk.

Confidence is high that Sunday will be the start of a string of
cooler days, with some sort of troffing and below normal heights
over the PacNW and northern Rockies. Such a pattern would yield
daily chances of showers and thunderstorms, along with the cooler
temps, but there is plenty of spread among potential details. An
organized deep trof and upsloping by Mon/Tue could bring
widespread precip and even high elevation snow (possible impacts
to Beartooth Highway), while an open wave passage would obviously
be drier (and windier). For now, look for temps cooling to the
60s/70s early next week along with a daily chance of showers &
thunderstorms.

JKL

&&

.AVIATION...


VFR will prevail for the forecast period. Scattered showers with
a few embedded thunderstorms are possible after 00Z tonight near
KLVM, moving east to KBIL and KMLS overnight. West winds of 25-35
kts are possible at KLVM, KMLS and KBHK Wednesday afternoon. TS


&&

.PRELIMINARY POINT TEMP/POPS...

    Wed     Thu     Fri     Sat     Sun     Mon     Tue
-----------------------------------------------------------
BIL 059/085 051/080 055/088 058/085 051/073 048/067 047/074
    21/U    00/U    02/T    31/U    20/B    23/T    32/T
LVM 050/081 045/081 050/086 051/081 042/068 041/064 040/071
    10/N    00/U    03/T    32/T    21/B    34/T    43/T
HDN 057/084 051/081 055/088 057/088 050/075 048/069 047/075
    21/U    00/U    02/T    31/U    20/U    23/T    32/T
MLS 060/082 050/080 055/090 060/085 053/073 049/068 050/075
    41/N    00/U    01/B    41/U    30/U    23/T    42/T
4BQ 060/083 053/081 056/091 060/088 053/075 049/071 051/079
    20/U    10/U    01/B    40/U    20/U    32/T    42/T
BHK 056/080 047/079 050/086 057/085 052/074 046/069 047/073
    20/N    00/U    02/T    41/U    31/U    33/T    43/T
SHR 055/084 049/081 052/088 055/087 047/075 045/070 044/076
    11/U    00/U    02/T    30/U    10/U    32/T    32/T

&&

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

&&

$$
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