538
FXUS65 KBYZ 220049
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
649 PM MDT Fri Jun 21 2024

.UPDATE...
Have cancelled all counties from a Severe Thunderstorm Watch.

A few factors greatly hindered our convection today: the low
stratus w/ capping, dry mid level air in our west, and a lack of
forcing. That said, there is a very weak mid level wave
approaching our west, and as a result we have seen some weak
convection develop just recently near the Crazy Mountains and
south of Billings. The potential for showers and non-severe storms
will continue thru the evening, and even a bit overnight in our
east, but the severe risk is greatly diminished at this point. JKL

&&

.DISCUSSION...

Through tonight...

Severe Thunderstorm Watch has been issued through 02Z for
Wheatland, Golden Valley and Musselshell Counties. Watch may be
extended further S later this afternoon. Good setup for severe
weather with strong trough overhead, surface CAPES of 1000-2000
J/kg, Bulk Effective Shear 35 to 50 kt and PWAT`s around 1 inch
with higher values over SE MT. Main threats are wind gusts to 70
mph and large isolated hail of 2 to 3 inches in diameter. A
tornado or two cannot be ruled out, but 0-1 km SRH has been
decreasing with successive HRRR runs, so this is a very isolated
threat. Watch may be extended S into Yellowstone and nearby
counties later this afternoon as low clouds scatter out.

Watch also issued for Sheridan County and Big Horn County til 03Z
given an uptick in activity there. Main threats are damaging
wind gusts to 70 mph and large hail with diameter up to 2 inches.
Arthur

Saturday through Thursday...

Upper level ridging will settle in over the Northern Rockies on
Saturday, resulting in 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 (40-80% chance). A brief shortwave
will flatten out the ridging Sunday evening, bringing the chance
for isolated showers and thunderstorms. Westerly flow and ridging
will rebuild into the new week with high temperatures in the upper
80s and low to mid 90s. Latest ensemble runs show a broad trough
dipping into the PNW on Thursday. With this, high temps closer to
normals are forecasted and an increase in the chance for
precipitation (20-40%).

Matos/TS

&&

.AVIATION...

Isolated showers and thunderstorms will impact the area thru the
evening, and even a bit overnight in the east, but the risk of
severe thunderstorms has greatly diminished. Local MVFR is
possible in any stronger showers or storms. Fog is possible
overnight, especially east of the foothills, though there is only
a 10-20% chance of fog impacting a TAF site. VFR will prevail on
Saturday. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 056/085 058/098 062/091 057/085 057/091 061/089 060/080
    21/U    01/U    11/U    00/U    00/U    11/B    23/T
LVM 051/085 053/094 056/089 051/087 052/091 055/087 053/077
    21/U    01/N    11/N    00/U    01/U    13/T    34/T
HDN 054/085 057/101 061/092 055/086 056/093 059/092 058/082
    41/U    01/G    21/U    10/U    00/U    11/U    33/T
MLS 056/082 058/096 065/088 058/083 057/090 061/090 060/083
    50/U    00/U    20/U    10/U    10/U    11/U    32/T
4BQ 056/083 058/098 066/091 058/084 057/093 061/094 061/085
    40/U    00/U    10/U    10/U    10/U    11/U    22/T
BHK 055/081 055/093 063/087 054/083 053/088 057/089 058/085
    41/U    00/U    10/U    10/U    11/U    11/U    32/T
SHR 051/083 054/096 061/094 054/085 055/091 058/092 055/084
    52/T    00/U    11/U    10/U    00/U    11/U    22/T

&&

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

&&

$$
weather.gov/billings