012
FXUS65 KBYZ 222123
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
323 PM MDT Wed May 22 2024

.DISCUSSION...
Today through Thursday night...

.KEY Messages...

- Heavy precipitation for lower elevations and heavy snow for
  mountains starting tonight lasting through tomorrow.

- Heavy rain could cause rises on area rivers and streams. Flood
  Watch has been issued for the Little Bighorn River at Hardin.

Today will see increasing clouds moving from west to east ahead of
our incoming storm. Starting around 18Z today showers and
possibly a few thunderstorms will begin to make their way into
our western regions. Starting overnight tonight, the boundary
layer will start to moisten creating a deep saturated layer to
300mb. This will create tall and skinny soundings indicating
favorable conditions for rainfall production. Around 12Z tomorrow,
precipitation will become more widespread across our western
regions. This will coincide with winds shifting to be out of the
north/northwest as precipitation moves across the region. As we
move into Thursday afternoon, the lower levels of the atmosphere
will start to dry out with precipitation coming to an end from
west to east with precipitation exiting into the Dakotas around
06Z Friday. Soundings indicate there will not be many
thunderstorms with this system as this should be mostly a rain
producing system. Widespread heavy precipitation is expected with
most of the region having a 50-70% chance of >1in. Locations
along the Dakotas border will see lighter precipitation with only
a 20% chance for >1in. The higher terrain will be getting heavy
snow from this event starting around 00Z this evening in the
Beartooth and Crazy Mountains and 06Z tonight for the Bighorns.
Most locations in the higher terrain have a 60-90% chance of
getting over 1 foot of snow. Winter storm warnings have been
issued for these locations.

With the heaviest precipitation (1-2in) falling in Bighorn County
and these locations seeing 150-300% of normal precipitation over
the last 30 days, there are some flooding concerns. A flood watch
has been issued for the Little Bighorn River at Hardin as it is
expected to reach around 9ft which is 1 foot above minor flood
stage.

Winds will be gusty tomorrow afternoon into evening, especially
in Sheridan County. Most of the region has a 50-70% chance of
getting a wind gust >30mph with Sheridan County having a 50-60%
chance of getting a gust >40mph.

Temperatures tomorrow will be below normal with most locations in
the low to mid 50s. Friday morning will be cool in the low 30s
with a freeze possible for most locations west of Billings.
Locations east of Billings will see temperatures in the mid to
high 30s. Torgerson




Friday through Wednesday...

Friday starts out with weak upper ridging in most of the Clusters
with the upper trough to our E. Deterministics showed weak
cyclonic flow over the area and NBM had 20-30% PoPs for showers
and thunderstorms from KBIL NW which agreed with Cluster mean
precip. Next upper trough moves in for Saturday with PoPs
increasing from W to E and near normal temps. PWAT`s will run
around average values. Highest PoPs were W of KBIL in the 60s.
Chances for .25 in of precip. or more were 20% Sat. night and
20-30% for Sunday. 40-60% PoPs continue for Sunday with weak
troughing over the region. Near normal temps continue for Sunday.
Monday will be warmer, in the low to mid 70s, as an upper ridge
builds into the area. Only have low PoPs in the NE Bighorns. High
temps climb into the low 80s for Tuesday and Wednesday with dry
conditions, until Wed. afternoon when SW flow is possible over the
area on the back side of the ridge. There is a 20-30% chance for
showers/thunderstorms from KBIL W. No fire concerns due to good
greenup and recent/expected weather systems. Arthur


&&

.AVIATION...

VFR conditions this afternoon will deteriorate to MVFR/IFR and
possibly lower from W to E tonight as a storm system moves into
the area with rain and a rain/snow mix. Mountains will become
obscured. Surface wind gusts will increase into the 30s and 40s
late tonight and Thursday morning across the area. MVFR/IFR or
lower conditions will continue over most of the area through Thu.
with mountain obscurations and gusty winds. Arthur

&&

.PRELIMINARY POINT TEMP/POPS...

    Thu     Fri     Sat     Sun     Mon     Tue     Wed
-----------------------------------------------------------
BIL 043/052 036/065 042/068 046/067 046/073 048/080 054/081
    7+/T    32/R    14/T    65/T    21/U    01/U    12/T
LVM 038/050 032/062 038/065 041/063 040/071 045/078 050/080
    89/T    12/T    16/T    65/T    11/U    01/U    12/T
HDN 043/052 034/067 039/071 046/068 043/074 045/081 051/084
    59/T    51/U    13/T    65/T    21/U    00/U    11/U
MLS 045/053 036/065 041/071 046/067 046/073 047/081 053/082
    29/T    61/U    11/B    45/R    21/U    00/U    11/U
4BQ 045/057 037/064 040/069 045/066 046/071 046/080 052/082
    28/T    81/U    01/B    45/R    21/U    00/U    00/U
BHK 043/055 034/061 038/070 042/066 043/070 044/078 049/079
    29/T    82/R    01/U    36/R    21/U    00/U    00/U
SHR 038/052 031/063 037/066 040/064 040/070 044/078 048/082
    39/T    71/U    02/T    56/T    21/U    00/U    01/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect until midnight MDT Thursday
      night FOR ZONES 67-68.
     Winter Storm Warning in effect from midnight tonight to 6 AM
      MDT Friday FOR ZONE 171.
     Winter Storm Watch in effect from Thursday morning through
      late Thursday night FOR ZONE 171.
WY...Winter Storm Warning in effect from midnight tonight to 6 AM
      MDT Friday FOR ZONE 198.
     Winter Storm Watch in effect from Thursday morning through
      late Thursday night FOR ZONE 198.

&&

$$
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