551
FXUS65 KBYZ 042059
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
259 PM MDT Tue Jun 4 2024

.DISCUSSION...

Today through Wednesday night...

Main concern for this forecast period will be gusty winds for the
western foothills today, transitioning to SE MT tomorrow.
Following the low currently to our NE in Canada, NW flow and
ridging will build in. Trailing energy from this low and a
resultant 700 mb jet will move through this afternoon through
Wednesday morning. Areas of Big Timber up through Harlowton will
remain in a High Wind Warning for westerly gusts up to 60 mph
through noon Wednesday. The Livingston area and surrounding
foothills will remain breezy, but winds should remain below
advisory level after this evening. Use caution when driving and
consider delaying travel. Hi- Res models are in good agreement
that showers associated with this jet will move through after
midnight, moving out of the area by late morning. This increased
chance for precip (10-25%) will mainly affect areas Billings
east. 700 mb winds (50-70 kts) mixing down along with high
pressure moving though will promote wind gusts up to 60 mph. As a
result, a High Wind Warning has been issued for Custer, Fallon and
Carter counties from 6 am to 6 pm MDT Wednesday. The remainder of
the region will continue to see gusts of 30-40 mph through this
evening, picking up again tomorrow morning and lasting through
sunset. High temperatures will be in the 70s today and Wednesday
with lows in the 40s and 50s.

TS


Thursday through Tuesday...

A building upper level ridge will bring dry conditions Thursday through
early Friday.

The combination of a fairly strong ridge over the western CONUS
and weak lows off the CA coast and near Baja will allow for
monsoon-like moisture to spread northward under the ridge.
Temperatures Friday through Sunday will be above normal, but more
importantly, the mid and upper level moisture (with precipitable
water values climbing above normal) should be enough for diurnal
weak thunderstorms each of these days. The main risk will be over
our southern mountains and foothills initially, but could spread
northward to include much of our area by Sunday. We do not see a
severe risk on any of these days, per the weak flow aloft, but
gusty and erratic outflow boundaries will probably be a theme with
this convection. By Monday, we could see height falls with a weak
Pacific trof and an increased chance (30-60%) of showers and
thunderstorms. Ensemble analysis shows Monday as the favored time
for potential meaningful QPF, as well as cooler temperatures.

For Tuesday, cluster analysis shows that models are in roughly
good agreement for drier weather as upper ridging dominates over
the western US. There is a 20% chance of showers and thunderstorms
in the mountains and adjacent foothills as the ridge axis still
looks a bit to the west of the area.

The string of warmer than normal days (and above freezing
temperatures at night) will promote mountain snow melt and
increased flows on rivers and streams for the end of the week and
through the weekend. Flooding is not expected, but folks will want
to stay aware of the higher water levels.

For anyone wondering where our severe thunderstorm season is,
there are subtle signs of a more convective-looking pattern by the
middle of June, with a Pacific Northwest trough and southwest
flow extending thru the northern Rockies and high plains.

JKL/RMS

&&

.AVIATION...

VFR will prevail through the TAF period. Winds will gust 35-45 kt
from the west/northwest through early this evening then weaken
for most of the area tonight. LLWS will develop north of KBIL-K00F
after 04z Wednesday and persist for most of the night. Isolated
showers (20% chance) will be over southeast MT 06z-15z Wednesday.
Surface winds will restrengthen after 09z Wednesday with
west/northwest winds gusting to 35-50 kt through Wednesday
afternoon. RMS

&&

.PRELIMINARY POINT TEMP/POPS...

    Wed     Thu     Fri     Sat     Sun     Mon     Tue
-----------------------------------------------------------
BIL 055/076 048/082 055/084 055/081 056/084 058/081 056/083
    10/N    00/U    00/U    00/U    01/U    33/T    21/U
LVM 055/076 045/084 052/084 052/081 053/082 053/079 051/081
    10/N    00/U    01/U    11/U    13/T    44/T    22/T
HDN 054/076 045/080 052/084 054/082 054/086 056/081 054/084
    20/N    00/U    00/U    00/U    01/U    33/T    21/U
MLS 055/071 045/078 050/084 053/079 052/082 056/081 054/083
    20/N    00/U    00/U    00/U    00/U    22/W    21/U
4BQ 055/071 046/079 052/084 054/081 053/083 057/081 054/082
    22/W    00/U    00/U    10/U    01/U    23/W    21/U
BHK 051/069 043/076 046/081 049/078 048/079 050/077 051/080
    20/N    00/U    00/U    00/U    00/U    22/W    21/U
SHR 050/073 045/079 052/084 053/079 051/084 054/078 052/080
    00/N    00/U    00/U    11/U    11/U    34/T    31/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...High Wind Watch in effect from Wednesday morning through
      Wednesday afternoon FOR ZONES 31>33-37.
     High Wind Warning in effect from 6 AM to 6 PM MDT Wednesday
      FOR ZONES 32-33-37.
     High Wind Warning remains in effect until noon MDT Wednesday
      FOR ZONES 63-141-172-228.
     Wind Advisory remains in effect until midnight MDT tonight
      FOR ZONES 65-66.
WY...None.

&&

$$
weather.gov/billings