560
FXUS65 KBYZ 250811
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
211 AM MDT Thu Apr 25 2024
.DISCUSSION...
Today through Friday night...
A more active weather pattern will overtake southern Montana and
northern Wyoming today and last through the weekend. This pattern
will bring cooler temperatures and an increasing chance of low
elevation rain and high elevation snow.
Water vapor imagery was showing a flat upper ridge over the
forecast area at the moment, with an upper low over southern
Nevada and a deepening trough over British Columbia. The ridge
will slide east today and open the area up to the influence of
southern Nevada low, and increasing moisture and energy. Weak
showers were already forming over the west early this morning and
these are progged to increase as the day wears on. Capes reach
around 200j/kg with effective bulk shear around 30kts over the
western half of the area, so would expect showers to fill in, with
a few thunderstorms, but nothing terribly strong. Precipitable
water amounts increase to around 0.60 inches, so showers shouldn't
be terribly heavy. Have high PoPs (50-70%) in the place for
locations west of Columbus, along the foothills and in the
mountains. Snow levels will be around 9 thousand feet today but
lower tonight and Friday. The probability of 0.20 inches of rain
is 20% for today and tonight for locations west of Columbus, with
a 5% chance in Billings. The mountains and foothills have a 30-50%
chance of 0.20 inches for that time period.
The east (mainly Carter and Fallon counties) will have potential
for a strong storm this afternoon, but it appears the risk for
severe weather has slide east a bit for today. Highest capes
(above 500j/kg) have pushed into the western Dakotas. HREF does
initiate a couple of stronger cells over these two counties around
22z (and this makes sense with an inverted surface trough in
place there), then pushes activity into the Dakotas by 01z, so
there may be short window of opportunity. Cape was weak through,
which limits potential, and given that the highest capes have
pushed east, will not mention severe in the that area today. SPC
keeps the marginal just southeast of Carter county. Expect pulsing
storms there today with small hail potential and locally heavy
rain, with PWATs around 0.80 inches. The probability of 0.25
inches of rainfall over the east is 20% for today and tonight over
Fallon and Carter counties.
Friday will be cooler with northerly surface winds, with a better
chance of showers for the entire area. The chance of showers rise
to 60-90% from Billings westward (highest over the mountains and
foothills), with a 60% chance of showers over eastern zones.
Precipitable water amounts rise to around 0.70 inches, so showers
will be a little heavier with locally heavy rain in play. Models
want to focus on locations west of Billings for the heaviest
showers, with the GFS putting down around 0.75 inches Friday. NBM
is not quite as heavy with the precip, placing a 40% chance of
0.25 inches Friday west of Columbus. At any rate, showers will be
more widespread Friday, especially west and over the mountains and
foothills, with brief and local heavy rain possible.
Snow levels will fall to around 7 thousand feet Friday, lowering
to around 6500 feet Friday night. So the mountains above 7
thousand feet will get a strong shot of wet snowfall. Upwards of a
foot is expected Thursday night through Saturday night above 7
thousand feet. NBM is projecting upwards of 15 inches through
Saturday night, while WPC was giving upwards of 18 inches. NBM
probabilities of 8 inches was still at 80%, with 60% chance of 12
inches. Will upgrade the Winter Storm Watch to a Warning, and run
it through Saturday night. TWH
Saturday through Thursday...
A Winter Storm Warning will continue for the Absaroka/Beartooth
Mountains and Crazy Mountains until Sunday morning. Adverse
travel conditions are expected and those in the high country
should be prepared for heavy accumulating snowfall.
Saturday, another closed low will eject through the Four Corners
into the Plains, following a prior low moving into the northern
Midwest. There will be lingering snow and precipitation into
Sunday morning, with a the western mountains picking up a few more
inches of snow. As for the rest of the forecast area, precip
chances will be highest into Saturday afternoon, with 50-90%
probabilities from Sheridan to Judith Gap and west. As for
locations east of this line, up to 40% prob for precip, with the
lowest chances in the northeastern areas. QPF amounts for the
weekend range from only a few hundredths in the east, to several
tenths, highest amounts for the mtns.
Chances for precipitation will persist through at Tuesday with
low to moderate chances. Another wave of energy will bring
moderate to high chances Sunday afternoon/evening, with a 50-90%
chance for west of Billings. QPF amounts aren't very high with
this quick shot, with the mountains seeing up to a 0.1". Lower
elevations will have chances for rain showers and a few hundredths
of QPF. Broad troughing will move into the region Monday, models
are once more depicting another round of low to moderate precip
chances, 30-60%, through the day.
Tuesday, zonal flow and some weak ridging will begin to settle in,
persisting through the week. With this pattern, warmer temps and
drier conditions are forecasted for the area. Highs in the 50s/60s
Saturday and Sunday, 60s to 70 Monday and Tuesday, and 70s/80s
Wednesday and Thursday.
Matos
&&
.AVIATION...
VFR conditions will prevail for the majority of the period.
Chances for precipitation and thunderstorms will increase
today. Sites with the best chances for thunderstorms today are
KLVM and KBHK, beginning around 20Z. Periods of MVFR are possible
with heavier showers and any thunderstorms. Mountain obscurations
are likely, with snow showers through the period.
Matos
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Fri Sat Sun Mon Tue Wed
-------------------------------------------------------
BIL 069 048/061 045/059 041/064 043/066 042/067 043/073
2/W 46/W 55/W 35/W 25/T 53/W 12/W
LVM 065 042/051 040/056 039/060 040/061 036/063 038/069
6/T 79/T 87/W 55/T 26/T 43/W 12/T
HDN 071 046/066 043/061 040/066 041/069 042/069 041/076
1/B 34/W 55/W 24/W 24/T 53/W 21/B
MLS 073 046/070 045/059 037/061 039/068 043/067 043/075
2/W 13/W 32/W 11/B 12/W 41/U 11/B
4BQ 074 047/066 045/057 038/059 038/067 042/068 042/076
3/T 24/T 54/W 22/W 12/W 31/B 11/U
BHK 075 044/064 041/054 033/056 034/065 039/064 039/071
5/T 46/T 42/W 12/W 12/W 32/W 11/B
SHR 068 044/061 042/055 035/059 037/065 039/066 039/075
3/W 45/W 77/W 34/W 23/T 42/W 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Warning in effect from midnight tonight to 6 AM
MDT Sunday FOR ZONES 67-68.
WY...None.
&&
$$
weather.gov/billings
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