064
FXUS65 KBYZ 091951
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
151 PM MDT Sun Jun 9 2024

.DISCUSSION...

Today through Monday Night...

This evening around 21Z showers and thunderstorms will begin to
make their way into the southwest mountains before spreading
across southeast Montana during the overnight. ECMWF shows some
upper level energy that is ejecting itself out ahead of the main
upper trough. PWAT values will be very high with values over an
inch across the region and some areas even getting near or above
1.25 in PWATS. Bulk shear values will be high due to the upper
jet with widespread values of greater than 40kts. Tonight around
03Z, locations from Powder River and Custer County and locations
to the east will see a low level jet with 850mb winds in the 30s
to 40s knots. This will set the stage for thunderstorms during
the overnight tonight and tomorrow morning that will have the
potential to produce <1 inch hail, strong wind gusts around 50kts,
and heavy rain. This will be despite the fact that instability
will be hard to come by with HREF showing only Bighorn County
having the potential for over 500J/kg of CAPE.

Tomorrow will see precipitation mostly come to an end in the
morning though a few showers and thunderstorms can`t be ruled
out. The upper level wave will move over the region setting up
more thunderstorm potential tomorrow especially after 21Z. The
biggest thunderstorm threat will be near the Dakotas border where
CAPE and shear will combine to create potentially severe
thunderstorms. CAM models are showing the development of
thunderstorms along a cold front near the Montana/Dakotas border.
The shear profile will have a significant perpendicular component
to the front indicating discrete convection. Where these storms
initiate will be important, if they initiate early on the Montana
side of the border, parts of Fallon and Carter Counties could see
the potential for severe thunderstorms producing hail and 60kt
winds.

Temperatures tomorrow will be in the high 70s to low 80s producing
high elevation snowmelt. This will combine with convective
precipitation around 0.5 inches over the higher terrain to
produce increased runoff. This will create rivers and streams in
the foothills that will likely be near bankfull. The Clarks Fork
at Edgar and Belfry is currently forecast to crest near minor
flood stage late Monday. People with interests along these streams
and rivers should take action to protect livestock and property.
Widespread flooding is not expected. Torgerson

Tuesday through Sunday...

WPC clusters are in good agreement that Tuesday through Thursday
will see zonal downsloped flow leading to dry conditions and the
warmest temperatures of the year. Looking at ensembles, these days
will see high probabilities (>70%) for RH values less than 20%
for locations mainly northwest of Billings. Temperatures for these
areas will be about 10 degrees above normal or more combined with
winds gusting into the 20s and 30s mph. Looking at cameras, area
fuels appear green and most of the drying over the past few weeks
has been for locations near the Dakotas border. Due to these
factors, fire danger appears to be relatively low at this time.
Temperatures for the middle of the week will be in the 80s for
most with some locations getting into the high 80s.

Clusters are now in good agreement that Friday will see shortwave
ridging enter the region ahead of a Pacific trough. This will lead
to continued above average temperatures in the 80s and dry
conditions. Next weekend models want to bring the trough into
CONUS and bring precipitation chances to the region. When the
trough enters the region and precipitation potential returns are
details that have little agreement at this time. At the very
least, next weekend appears to be more active and unsettled even
tough details are not clear.

With multiple days of above average temperatures, snowmelt looks
to increase over the coming week. This could lead to increases on
area rivers and streams with some nearing bankfull. People with
interests in these areas should prepare for high flow conditions.
Torgerson


&&

.AVIATION...


A disturbance moves into the western mountains and foothills late
this afternoon. This feature will generate scattered to numerous
showers and thunderstorms moving west to east across the forecast
area through late tonight. A second disturbance will move into the
area late tonight generating an additional round of convection
into tomorrow morning. Precipitable water values are over an inch
today meaning locally heavy downpours will likely produce MVFR to
occasional IFR conditions near precipitation areas. Mountain
obscuration is likely with convection over the higher terrain as
well. Small hail and gusts over 35kts are additional threats with
convection through late tonight. In the pre-dawn areas can`t rule
out localized fog development where heavier precipitation falls. A
front drives through gusty northwest winds (20 to 30 kts) by late
Monday morning ending precipitation threat. Chambers
&&

.PRELIMINARY POINT TEMP/POPS...

    Mon     Tue     Wed     Thu     Fri     Sat     Sun
-----------------------------------------------------------
BIL 058/082 055/086 057/086 054/081 056/087 058/081 053/075
    45/W    00/U    20/U    00/U    11/B    32/T    22/B
LVM 053/077 047/083 051/083 047/082 051/085 051/078 045/070
    76/T    00/U    10/N    00/U    13/T    33/T    23/T
HDN 058/083 053/086 057/086 054/082 055/090 058/082 052/078
    64/T    00/U    30/U    00/U    11/U    32/T    32/B
MLS 060/081 052/085 059/084 054/080 054/087 061/082 055/075
    55/T    00/U    30/U    10/U    11/U    42/W    32/B
4BQ 061/081 054/085 060/085 056/082 056/090 062/083 055/078
    44/T    00/U    30/U    10/U    11/U    42/W    32/B
BHK 056/078 050/082 055/083 050/080 050/084 057/082 052/077
    37/T    10/U    10/U    10/U    12/U    43/T    32/W
SHR 055/078 051/083 055/085 053/080 053/089 057/080 051/076
    43/T    10/U    20/U    00/U    11/B    32/T    22/U

&&

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

&&

$$
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