809
FXUS65 KBYZ 210849
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
249 AM MDT Fri Jun 21 2024

.DISCUSSION...

Today through Saturday night...

Low level east to northeast winds were advecting stratus and
patchy fog into the area early this morning, greatest over eastern
areas. At the same time, shortwave energy moving in from the
southwest and elevated instability over the region was allowing
isolated to scattered showers and isolated thunderstorms over
portions of the area. Heading into the morning hours, expect
shower and thunderstorm chances to increase over central and
eastern areas (40-70%) as a shortwave moves in from the southwest.
Thunderstorms will be capable of small hail and pockets of heavy
rain through the morning hours.

Heading into the afternoon and evening, shower and thunderstorm
chances increase over the west and central areas (40-60%) and
decrease over the east as another shortwave moves through the
region. Lingering stratus over eastern areas will keep cooler
conditions in place along with more convective inhibition. MUCAPE
values are progged to increase towards 2,000 J/kg over the
central and west, with deep layer shear (0-6km) values of 30-40
kts. Currently, the SPC has a Slight risk for severe thunderstorms
over western and central areas, decreasing to a marginal over the
east. Greatest threats with the thunderstorms will be large hail,
strong winds and heavy rainfall (PWATS near 0.90 to 1.0 inches).
Thunderstorms will decrease from west to east during the late
evening and night hours.

Drier conditions move into the area on Saturday as ridging builds
over the region. High temperatures are expected to range from the
lower 70s to the lower 80s today, coolest over the east. Highs in
the 80s can be expected for Saturday, with ridging building into
the region. STP

Sunday through Thursday...

Upper level ridging in place will provide hot and dry conditions
with several locations nearing record highs. High temperatures
will be in the 90s for much of the region with locations along
the river valley most likely to hit 100 degrees (30-70% chance).
Ridging will slightly breakdown late Sunday as shortwave
troughing over NW MT is forecasted to move over northern MT. Weak
perturbations from troughing will allow for some weak, high-
based, isolated showers and thunderstorms Sunday afternoon and
evening. Westerly flow will be in place Monday before ridging
builds back in for the rest of the period with highs expected to
be in the 80s/low 90s. TS

&&

.AVIATION...

Fog/low stratus is possible for all TAF sites overnight until
around 14Z leading to MVFR/IFR. Scattered showers with isolated
thunderstorms will begin to develop just before 12Z for KBIL, KSHR
and KMLS, tracking east into the early afternoon. Brief MVFR
conditions are possible under any thunderstorms with heavy rain.
TS

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Sat     Sun     Mon     Tue     Wed     Thu
-------------------------------------------------------
BIL 079 056/084 058/097 061/090 057/085 057/091 061/091
    3/T 41/U    01/U    11/U    00/U    00/U    01/U
LVM 080 050/086 054/094 056/089 050/086 052/091 055/087
    3/T 31/U    01/N    11/N    00/U    01/U    12/T
HDN 081 054/085 057/099 060/091 055/087 056/093 059/093
    5/T 41/U    01/U    21/U    10/U    00/U    11/U
MLS 077 056/082 057/096 065/088 056/085 057/090 061/091
    6/T 51/U    00/U    20/U    10/U    00/U    11/U
4BQ 076 055/083 057/097 066/090 058/086 058/093 062/092
    7/T 21/U    00/U    10/U    10/U    01/U    11/U
BHK 073 053/080 054/092 062/088 054/084 053/088 057/087
    6/T 31/U    00/U    20/U    10/U    01/U    11/U
SHR 078 051/083 055/097 061/092 054/086 055/093 057/093
    7/T 51/U    00/U    11/U    10/U    01/U    11/U

&&

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

&&

$$
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