463
FXUS65 KBYZ 202014
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
214 PM MDT Thu Jun 20 2024

.DISCUSSION...
Tonight through Friday night...

Shortwaves and jet energy will move through WSW flow aloft
tonight. With low-level ESE flow, PWAT`s will climb to 1 inch from
KBIL S and E. Some areas showed MUCAPE of 500-1000 J/kg (elevated)
and bulk effective shear around 40 kt tonight. So with enough lift
there could be a few strong storms, mainly along the northern
tier, N of KBIL, where HREF showed a few updraft helicity tracks.
Had 20-30% PoPs much of the night over portions of the area based
on CAMS. Had higher PoPs E of KBIL late at night as second wave
moves through the area. HRRR showed fog, possibly dense, over
Carter and Fallon Counties overnight. Satellite and web cams had
low clouds moving into SE MT. Added areas of fog to the far E
overnight, with patchy fog elsewhere N and E of KBIL. Next shifts
can keep an eye out for possible dense fog advisory. It will be a
warm and humid night with lows well into the 50s.

Stronger trough moves across the area Friday through Friday night.
HREF showed a few helicity tracks S and SE of KBIL Fri. morning.
Helicity tracks become strong in the afternoon with an area of
tracks N of the forecast area and a second area over Sheridan
County and far SE MT. Northern area of tracks weakens as it moves
SE into the forecast area in the evening. MUCAPEs Fri. afternoon
and evening will be 1000-2000 J/kg and bulk effective shear will
be 30 to 50 kt with the strongest parameters from KBIL E and S.
Due to continued ESE flow, some areas showed an inversion on GFS
soundings...so this inversion along with cloud cover could inhibit
strength of some of the storms. High PWAT`s continue which will
bring heavy rainfall with the storms. So, hail, wind and heavy
rainfall will be the threats with any strong to severe storms.
Highest PoPs (50-60%) will be E of KBIL in the morning. 30-50%
PoPs in the early afternoon will increase late in the afternoon
and continue into the evening. PoPs will quickly decrease W to E
late Fri. night. Temps will be in the 70s to low 80s on Friday and
in the 50s Fri. night. Arthur

Saturday through Wednesday...

Upper level ridging will continue to build into the Northern
Rockies through the extended forecast period. Increasing heights
will result in above normal temperatures and mostly dry
conditions. The warmest day in the extended forecast will be
Sunday with highs in the mid 90s, approaching 100F. The
probability of a high temperature of 100F or greater is 20-60%
from Columbus to Busby and Miles City. There is a low chance
(10-25%) for showers and thunderstorms Sunday night as the ridging
is briefly flattened by a weak shortwave. High temperatures for
the rest of the week will be in the mid-upper 80s to mid 90s.

Rivers and streams have fallen considerably over the past week
but still have a bit to go to get down to normal summer flows. If
you head out to the rivers to cool down this weekend be sure to
wear life-vests and continue to use extra caution, especially
with children. Matos

&&

.AVIATION...

A 20-30% chance of thunderstorms will affect areas from K3HT E to
KMLS and KBHK this evening through 06Z. Some storms could be
strong with gusty winds and hail. Expect MVFR/IFR with the storms.
Otherwise, a few storms are possible around KSHR and Ekalaka.
Chances for showers and thunderstorms increase late tonight over
much of the area E of KLVM and continue into Friday morning.
MVFR/IFR or lower conditions are possible in the thunderstorms.
Kept just VCSH in KBIL, KSHR and KMLS TAFs due to uncertainty in
thunderstorm locations that far out in time, but a thunderstorm
cannot be ruled out. Expect increasing chances of strong to
severe thunderstorms with MVFR/IFR or lower conditions Friday
afternoon. Arthur

&&

.PRELIMINARY POINT TEMP/POPS...

    Fri     Sat     Sun     Mon     Tue     Wed     Thu
-----------------------------------------------------------
BIL 057/079 056/084 059/097 062/091 058/088 058/090 061/093
    24/T    31/U    00/U    11/U    10/U    11/U    12/T
LVM 049/080 050/086 054/095 056/090 052/087 053/090 056/089
    14/T    21/U    01/N    11/N    11/U    11/U    13/T
HDN 056/082 054/085 057/099 060/092 056/090 057/092 060/096
    55/T    41/U    00/U    21/U    10/U    11/U    11/U
MLS 057/078 057/082 058/096 064/089 058/087 058/090 063/093
    26/T    51/U    00/U    20/U    10/U    11/U    21/U
4BQ 058/079 057/084 058/097 066/091 059/088 060/091 063/094
    36/T    41/U    00/U    10/U    10/U    11/U    11/U
BHK 054/075 054/080 054/092 061/088 055/085 055/086 057/089
    36/T    51/B    00/U    10/U    11/U    11/U    12/T
SHR 052/080 051/083 055/097 061/092 055/087 056/091 059/093
    37/T    31/U    00/U    10/U    10/U    11/U    11/U

&&

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

&&

$$
weather.gov/billings