006
FXUS65 KBYZ 190057
AFDBYZ

Area Forecast Discussion...Updated
National Weather Service Billings MT
657 PM MDT Fri Sep 18 2026

.KEY MESSAGES...

- A few strong thunderstorms are possible over southeast Montana
  this evening.

- Flood Watch this evening through Sunday for much of the area.
  Widespread precipitation this afternoon through the weekend,
  with potential for locally heavy rainfall through Saturday
  night.

- Widespread 50-95% chance of an inch of rainfall. 50-80% chance
  of two inches of rainfall for portions of south central Montana.

&&

.DISCUSSION...

Today through Thursday...

Showers and embedded thunderstorms will move in from the
southwest this afternoon and evening, with an area of showers
developing over South Central Montana overnight and continuing
into the weekend. Heavy rain is anticipated, particularly tonight
through Saturday, and a Flood Watch is in effect this evening
through Sunday afternoon for South Central Montana, much of
Southeast Montana, and portions of Wyoming, including Sheridan
County. Over northern Wyoming into Southeast Montana, occasional
rounds of precipitation are expected before an area of stronger
showers and thunderstorms move through Saturday afternoon. Recent
burn scars will be highly susceptible to flash flooding and
debris flows. Those living near recent burn scars should have a
plan of action to seek safety should heavy rainfall develop in
those locations. Stay aware of the directions of local officials
and any Flash Flood Warnings that may be issued.

Currently, there is a widespread 50-95% chance (highest
where there is a Flood Watch) of at least 1 inch of precipitation
and a 50-80% chance of at least 2 inches from east of Livingston
through Miles City through Sunday evening. Locally higher amounts
of 4+ inches will be possible for areas where slow moving
thunderstorms develop or where thunderstorms repeatedly move
through.

The risk for severe thunderstorms today is low, although a
stronger storm or two may develop late this evening over Southeast
Montana. The main threat remains heavy rain, and wind gusts up to
50 mph will be possible with any stronger storm.

Snow levels fall to around 11 kft by Saturday afternoon, allowing
a few inches of snow over the highest peaks. During the overnight
hours tonight and Saturday night, a dusting of snow (30% chance)
may fall on the Beartooth Pass.

After the system exits the region Sunday, conditions trend warmer
and drier. Highs over the weekend will generally be in the 60s,
increasing to low 70s by Monday and near 80 by midweek. Archer

.AVIATION...

00z update:
A fall weather system will bring precipitation and low to mid
level clouds to much of the area tonight into this weekend.

Scattered showers and isolated thunderstorms have developed and
will move northeastward this evening. Showers will then become
more widespread tonight into Saturday, with occasional embedded
thunderstorms mainly during the day on Saturday. Look for showers
to gradually diminish through the day Sunday. The main concern
with thunderstorms this weekend is heavy rain, though gusty winds
are possible this evening. Along with the precipitation, broken
to overcast low to mid level clouds are expected to develop
tonight into Saturday. With this, a period of MVFR to IFR
conditions are forecast across much the area Saturday. During this
time, expect mountain obscurations to occur as well.

Outside of the precipitation, areas of fog should develop in far
southeast MT, east of KMLS-K00F, after 06z Saturday and then begin
to diminish after 14z Saturday. The fog will reduce visibility to
less than 1/2 mile in this area. LA/RMS

&&

.PRELIMINARY POINT TEMP/POPS...

    Sat     Sun     Mon     Tue     Wed     Thu     Fri
-----------------------------------------------------------
BIL 056/061 053/063 050/072 050/078 053/078 053/079 053/080
    ++/T    98/T    10/B    00/U    11/U    00/U    00/B
LVM 049/059 046/066 043/075 046/078 048/078 048/080 049/080
    +9/T    84/T    10/U    00/U    10/U    00/U    00/B
HDN 054/064 050/064 047/073 046/080 048/080 047/081 049/082
    9+/T    98/T    20/B    00/U    10/U    00/U    00/B
MLS 058/064 054/063 051/071 051/078 054/080 054/081 055/082
    79/T    99/T    21/B    00/U    01/U    10/U    00/B
4BQ 059/065 054/062 050/068 051/077 054/079 054/081 055/082
    88/T    +9/T    51/B    00/U    12/T    10/U    02/W
BHK 052/065 048/061 046/067 046/075 049/080 051/082 051/081
    48/W    99/W    21/E    00/B    01/B    10/U    10/B
SHR 051/065 047/063 043/071 042/078 047/079 046/081 047/082
    8+/T    98/T    42/W    00/U    11/U    01/U    01/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Flood Watch in effect through Sunday afternoon FOR ZONES
      29>32-34-36-40-42-56>58-63>68-138-139-141-169>173-228-235.
WY...Flood Watch in effect through Sunday afternoon FOR ZONES
      198-199.

&&

$$
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