038
FXUS65 KBYZ 071949
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
149 PM MDT Fri Jun 7 2024

.DISCUSSION...
Today through Saturday Night...

Today will see a weak low pressure system moving through the
region bringing a cold front through. Winds have already turned
more northwesterly across most of the area with locations near the
Dakotas border expected to get the shift soon. This shift will
bring cold air advection and act to limit high temperatures today
with peak temperatures coming early in the afternoon. Most
locations will top out in the mid 70s to low 80s. Winds today
will be breezy with low level lapse rates in the 7-8C/km range
mixing down 700mb winds in the 30s kts. NBM is giving the entire
region a >50% chance of seeing a wind gust over 30mph today. As we
head toward evening, winds will lighten up from west to east and
become easterly.

Tomorrow will see continued cyclonic flow leading to the potential
(10%) for some showers across much of the region. This
precipitation is not being captured by the NBM but is being shown
in some of the Hi-Res models leading to its inclusion in the
forecast. There is currently a surface high pressure system with
cool temperatures to our north. This will slowly drop south
bringing cooler temperatures tomorrow in the low to mid 70s for
most. Winds will be calmer tomorrow as upper level winds will be
much weaker than today.

Warm temperatures and snowpack that is ready to melt is leading to
water rises on area streams and rivers. Got some reports this
morning from Sheridan County about ongoing minor flooding on Big
Goose creek. A flood advisory was issued for these areas. No gauge
site is currently forecast to exceed flood stage but some are
forecast to some close. People should use caution around area
waterways and be on alert for potential rises. A hydrologic
outlook has been issued for this hazard. Torgerson


Sunday through Friday...

Sunday will see the surface high pressure continue to drop south.
How far south it drops will determin what temperatures will be
like. The deterministic GFS wants to bring it near the
international border keeping temperatures down into the low to mid
60s, while others keep it farther to the north with temperatures
in the low to mid 70s. This leads to a lot of uncertainty in the
high temperature forecast for Sunday which is also seen in the
ensembles.

The upper low bringing cooler temperatures will be fairly
stationary until it gets kicked out by an upper level wave that
will bring the chance for thunderstorms late Sunday into Monday.
Overall, it seems models have cut back on precipitation from this
wave. There is significant disagreement on the location of the low
with the GFS taking it farther south and the Canadian farther
north through Montana with the ECMWF somewhere in the middle. The
ECMWF brings by far the most precipitation to the area of around
0.8 inches for Billings. However, looking at the ECMWF ensembles
the deterministic is an outlier above the 90th percentile. There
is a common theme in the ensembles with the mean values being much
higher than the medians, in some cases even being around the 75th
percentile. This indicates some of the higher solutions are
dragging the mean values unrealistically high. Overall, the NBM is
giving a 25-45% chance of getting greater than 0.1 inches of
precipitation with higher numbers around 60-70% for the southwest
mountains. GFS soundings for Monday are showing CAPE values around
500J/kg with effective layer shear values being around 40kts. With
support from an upper wave and PWATS near 0.9, there will likely
be thunderstorms even without great instability. Thunderstorms
will also lead to more hit or miss precipitation.

Through the middle of the week, ensembles are showing a mostly
downsloped pattern with waves running over the top leading to a
warm and dry pattern. Towards the end of the week there is good
cluster agreement that a Pacific trough will form off the coast.
Exactly when this will happen and what impact it will have on the
weather is not clear at this time.

After a cool Sunday temperatures will rise through midweek with
low to high 80s by Tuesday. Temperatures will remain in the 80s
through the rest of the work week. These higher temperatures will
continue to create hazards on area rivers and streams from
snowmelt. People in these areas should be prepared for possible
rises. Torgerson


&&

.AVIATION...


VFR conditions will prevail for the next 24 hours. Isolated
showers are possible tonight into early Saturday morning as a
disturbance crosses the region. Chambers
&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 052/076 051/068 051/074 053/085 058/086 054/082 055/083
    11/U    00/B    34/T    10/U    11/U    11/U    11/B
LVM 047/078 048/068 048/075 049/082 051/083 048/080 050/080
    11/U    02/W    56/T    11/U    11/U    11/U    12/T
HDN 052/077 051/071 051/074 050/086 056/086 053/083 056/085
    12/W    00/B    33/W    10/U    21/U    10/U    11/B
MLS 053/073 049/065 050/069 048/083 058/085 054/082 054/084
    12/W    11/B    23/W    10/U    20/U    10/U    21/B
4BQ 053/076 052/068 052/073 049/083 058/085 055/084 056/085
    11/U    11/B    23/T    20/U    20/U    10/U    22/T
BHK 046/072 044/065 046/067 046/080 054/084 051/081 051/082
    01/B    01/B    23/T    20/U    10/U    10/U    22/W
SHR 048/076 048/071 050/073 048/082 054/085 053/082 053/084
    12/W    11/B    23/T    20/U    11/U    10/U    12/T

&&

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

&&

$$
weather.gov/billings