723
FXUS65 KBYZ 032038
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
238 PM MDT Fri May 3 2024

.DISCUSSION...

Tonight through Sunday night...

The Northern Rockies region is under cyclonic, northwesterly flow
at 500 mb this afternoon, with considerable cloud cover and a few
isolated rain/snow showers. Changes are in store though,
beginning tonight.

Tonight into Saturday night, the 500 mb trough that has been
affecting our weather the past few days will move eastward enough
to allow shortwave ridging to move into our area from the west.
This ridge will bring dry weather and partly to mostly sunny skies
to the area. We will also experience some warming as surface high
pressure moves into the northern/central Plains and low-level
southeasterly winds on the western side of the surface high
facilitate compressional warming and warm air advection. A
corridor of wind gusts to 30-35 mph will exist from Wheatland
County to southern Carbon County on Saturday.

Sunday, a 500 mb low will move from the OR/CA/NV area to southern
ID/northern NV. This system will bring clouds to the area, and an
increasing chance of showers from west to east. For Sunday
afternoon, PoP values are 20-90% over south central MT and
western Sheridan County, WY. Isolated thunderstorms are possible
as well (20% chance). The greatest PoP values are in the Crazy
and Beartooth/Absaroka Mountains.

Furthermore, continued low-level southeasterly flow will cause
additional warming on Sunday. Over southeast MT and Sheridan
County, WY, southeasterly winds will gust to 35-45 mph. Minimum
relative humidity values should drop to around 20% Sunday
afternoon. So, the combination of warm temperatures, gusty winds
and low relative humidity will create elevated fire weather
concerns Sunday in southeast MT and the lower elevations of
Sheridan County, WY, wherever a greenup has not yet occurred.

Sunday night, the 500 mb low will move into western WY and bring a
40-90% chance of showers (with a 20% chance of thunderstorms) to
the area with the highest PoP values in the mountains and areas
west of Billings. Models generally agree up to this point in the
forecast (through Sunday night) that the greater precipitation
amounts, generally 0.10 to 0.50 inches, will be west of southeast
MT. In addition, a cold front will cross the area Sunday evening,
bringing cooler air to the area but still warm enough to support
rain in the lower elevations. Snow levels will fall from
9,000-10,000 feet Sunday evening to 6,000-8,000 feet by Monday
morning.

Low temperatures will generally be in the 20s to lower 30s
tonight, then 30s-40s Saturday night and Sunday night, with Sunday
night the warmer night. High temperatures will mainly be in the
60s Saturday and 60s-lower 80s Sunday (warmest in southeast MT and
Sheridan County, WY).  RMS

Monday through Friday...

By Monday, ensembles place an upper level low will over western
Wyoming tracking east into eastern MT and western Dakotas by
Monday night. This low will linger over the western Dakotas
through Wednesday bringing multiple rounds of precipitation as
well as strong northwest winds. There is still much spread amongst
models on total QPF as well as the timing of the heaviest
precipitation. Mon through Wed night, the region has about a
60-85% chance of getting at least a half an inch with about a
50-70% chance of at least an inch for southeast MT (areas east of
Billings). For this same time period, the Absaroka/Beartooths and
Bighorns have about a 40-60% chance of getting at least a foot of
snow. Snow levels will generally be around 5000-6000 ft. With
that, locations along the foothills could see a few inches of snow
with Red Lodge at about a 40% chance of getting at least 3
inches. With regards to winds Monday, the strongest gusts will be
off the western foothills along 1-90 as well as the high hills in
southern Big Horn Co. These areas have about a 40-60% chance of
getting wind gusts of at least 50 mph. Windy conditions will
persist through Wednesday with gusts into the 30s and 40s.
Precipitation chances start to diminish Thursday into Friday. Keep
an eye on the forecast as placement of timing and amounts are
likely to chance. Also be aware of changing cool and wet
conditions for young livestock.

High temperatures will be in the 50s through the week, possibly
reaching the 60s by Friday. TS

&&

.AVIATION...

Isolated showers will be possible through this afternoon. VFR
conditions will prevail through the period. TS

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 030/065 040/074 047/058 043/055 041/051 040/057 042/067
    00/U    02/W    78/R    45/R    67/R    66/R    33/R
LVM 028/063 042/066 040/053 037/050 036/048 036/052 036/062
    00/B    17/T    98/T    46/O    67/O    55/O    23/R
HDN 028/068 039/080 046/059 041/056 039/051 039/058 040/067
    00/U    02/W    69/R    56/R    77/R    76/R    43/R
MLS 028/063 041/081 050/060 042/052 038/052 041/061 042/067
    10/U    01/N    59/T    76/R    78/R    75/R    32/R
4BQ 028/065 043/080 049/059 040/053 038/049 039/056 041/063
    00/U    01/N    59/T    65/R    67/R    76/T    33/R
BHK 025/060 038/074 048/060 038/050 034/051 037/058 037/063
    10/U    01/N    59/T    87/R    77/R    65/R    33/R
SHR 026/066 039/077 042/055 038/056 036/050 035/052 037/061
    10/U    02/W    69/T    66/R    77/R    77/R    44/T

&&

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

&&

$$
weather.gov/billings