Damaging Winds in Montana, August 30, 2023

Area Forecast Discussion
National Weather Service Billings MT
241 AM MDT Wed Aug 30 2023

.DISCUSSION...

Tonight through Thursday evening...

Currently, the low over Washington is bringing a cold front
tracking NE through MT. Winds ahead of the front (~25-30 mph)
will be out of the SW, shifting W/NW with the frontal passage.
This will bring light rain and isolated thunderstorms through
western Bighorn and northern Rosebud counties through the night as
well as areas of SE MT through the morning. Relative humidity
values will be low this afternoon with minimum values in the
upper teens to low 20s for a majority of the area. Breezy
conditions will also prevail through the day (especially at higher
elevations), both of which could be of concern for fire weather.
Will be something to keep an eye on through the period.
Q-vectors indicate accent will still be in place through this
evening, so scattered showers and thunderstorms are possible
through the day. Hi-Res models show convection associated with the
low generally developing in the afternoon NNW of Billings,
tracking east into the evening (20-40% chance). Gusty winds (30-40
mph) for Rosebud county and east will be the main concern with
any thunderstorms that form.
Thursday looks to be warm and breezy. With the jet still in place
over MT, windy conditions will prevail, especially in the
morning. Could see gusts from 25-35 mph out of the west mainly
for western and northern parts of the CWA.
Smoke could affect areas of SE MT with winds out of the west, but
this is all dependent on fire behavior through the day.
High temperatures will be in the 70s/80s for Wednesday and
Thursday. TS

Thursday Night through Tuesday...

Deepening low along the Pacific coast will allow southerly flow
aloft to redevelop, bringing warmer air and increasing monsoon
moisture thru the end of the week. The regime change will be
quick, with some showers possible over the Beartooth-Absarokas by
Thursday night. Convection Friday and Saturday should be confined
to the southern mountains and perhaps foothills as the moisture is
at least somewhat suppressed by westerly flow across northern MT
and the Dakotas. Temps should return to near 90F Friday and the
low-mid 90s Saturday.

Low to our southwest will begin to eject to the northeast Sunday,
bringing increasingly diffluent flow aloft and a much better
chance of thunderstorms across more of the area. The low will lift
thru the region Monday, continuing the very good chance of precip
(60-80%), and this is where model spread becomes significant.
Consensus is for an open wave but some ensembles show a closed mid
level low and thus higher QPF...some suggesting an inch or more
of rain somewhere depending on the exact track of the trof/low.
All of this being said, confidence is high for a cooling trend
with increasing showers and thunderstorms early next week, but low
in the details. By the way, there is a lagging Pacific wave that
will prolong the chance of showers and thunderstorms through
Tuesday. Look for temps in the 80s to lower 90s Sunday then mostly
70s Monday & Tuesday.

JKL

&&

.AVIATION...

Pre-frontal SE winds will gust to 30 knots from KMLS to KBHK
early this morning (thru ~14z)...with low level wind shear in this
area as well (southerly winds up to 45 knots off the surface).
Cold front arriving from the west will bring a shift to gusty W-NW
winds today with 30-40 knot gusts expected along the western
foothills (strongest at KHWQ). VFR will generally prevail over the
next 24 hours, but there will be a few morning showers/t-storms
then scattered evening thunderstorms (mainly east of KBIL) that
could produce local/brief MVFR along with erratic wind gusts. JKL
&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 086 057/084 055/089 061/093 064/089 060/072 052/076
    1/N 10/U    00/B    00/U    11/B    66/T    52/W
LVM 077 050/081 049/086 055/087 057/082 052/069 045/074
    1/N 10/N    11/B    10/N    13/T    67/T    42/T
HDN 087 052/087 052/090 057/095 060/090 056/075 049/078
    1/U 20/U    00/B    00/U    11/B    65/T    52/W
MLS 087 057/084 055/090 061/095 064/092 061/077 052/073
    2/W 40/U    00/B    00/U    00/U    55/T    42/W
4BQ 088 055/086 055/092 060/094 064/093 060/079 052/076
    0/U 20/U    00/B    00/U    00/U    55/T    52/W
BHK 089 053/083 050/089 058/094 061/092 058/078 050/073
    2/W 40/N    00/U    00/U    00/U    44/T    42/W
SHR 086 048/084 049/090 057/092 058/088 054/073 047/075
    0/U 10/U    00/B    00/U    01/B    65/T    42/T

&&

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

&&

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