Name: Wildfire in Montana, September 2 to 28, 2020
Start: 2020-09-02T11:00
End: 2020-09-28T17:00
Location: Montana

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS BYZ wrote it up.

The BobCat fire was detected on September 2nd on private lands approximately 7 miles southeast of Roundup east of MT Highway 87. The fire burned in tall grass, intermixed with ponderosa pine stands and sagebrush. Primarily wind-driven, the fire spread to the southeast from the origin. The total number of personnel working the fire was 104. Total acreage burned was 30,030. The Musselshell County DES reported that a structure assessment found 14 primary and 34 secondary/outbuildings were lost in the fire.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Billings, MT wrote its last area forecast discussion before the first event at Sep 2, 7:41 AM MST, 3 hours 19 minutes earlier.

Area forecast discussion, Sep 2, 7:41 AM MST, 3 hours 19 minutes before

Area Forecast Discussion
National Weather Service Billings MT
841 AM MDT Wed Sep 2 2020

.UPDATE...

Made a quick update this morning to adjust winds across the west
to account for a quicker than expected transition to strong and
gusty westerly winds.

Winds have already shifted to westerly in Livingston, with gusts
to 50 mph, and Billings is already gusting to about 30 mph. This
is at least a couple of hours early for Livingston, and a few
hours early for Billings. Otherwise, the inherited forecast
appears in good shape, with strong and gusty winds expected to
persist through the day. Gilstad

&&

.DISCUSSION...

Today through Thursday night...

Hot and dry day today as water vapor pointing to a low to mid
level pocket of dry air over western Montana heading into southern
Montana and northern Wyoming. As this occurs, a surface trough
will slide across northeast Montana and increase mid level flow
which will add downslope warming. Highs in the low to mid 90s look
on track. Humidity levels should drop to around 10 percent with
impressive downslope drying today. 850-700mb winds of 40-45kts
should be able to mix to the surface this afternoon, for gusts of
40-50mph, with a stray gust or two of 55mph not out of the
question. Will have to watch the area from Livingston to Big
Timber to Harlowton, as models indicate 50kt winds right around
700mb that may be able to surface for a gust of 60mph. Gradient
looks good too, but for only a brief moment in the early to mid
afternoon. Still, would not be surprised to see a gust of 60mph in
this corridor. Red Flag Warnings look in really good shape. Be
careful out there today, as this is a potentially dangerous fire
weather day.

A strong cold front drives through this afternoon and early this
evening. Winds snap to the north, and strong surface pressure
rises behind the front, will push winds to 50mph across a large
portion of the area. Winds may be able to touch 55-60mph briefly
with the frontal passage as dry air will help accelerate things.
The front will come through dry and winds should decrease behind
the frontal passage by about 2-4 hours. Thursday will be cooler
and less windy. Highs will be in the low to mid 80s Thursday. TWH

Friday through Tuesday...

Upper ridging will bring more dry weather with warming
temperatures and light winds on Friday.

Saturday will be a hot, dry and breezy day. A cold front will
cross the area at some point Saturday afternoon into Saturday
night (models differ on timing) and cause winds to turn
northerly. The combination of hot/dry/breezy conditions will
produce fire weather concerns, and a potential daytime frontal
passage would add to the concerns. In addition, the dry air looks
to preclude any precipitation from developing Saturday and
Saturday night.

Northwesterly flow aloft will dominate the weather Sunday through
Tuesday. On Sunday, the Northern Rockies will largely be in
between weather systems, which will give dry conditions with
cooler air. Then Sunday night into Monday night, models bring a
potent shortwave trough southeastward from western Canada into
Montana. This system should bring another cold front across the
area Sunday night, cooling temperatures further on Monday from
Sunday's expected highs. It should also provide large scale ascent
to produce a widespread, steady rainfall over much of the region
during the day Labor Day. Snow levels look to drop to around 9000
feet on Monday so the Beartooth Pass could be impacted.
Conditions should mostly dry out on Tuesday, though a few isolated
showers are possible.

High temperatures will generally be in the upper 80s to lower 90s
Friday and 90s on Saturday. Ensemble model solutions are then
indicating increased uncertainty in the temperatures for Sunday-
Tuesday. Our forecast reflects a blend of solutions and projects 70s
east and 80s west Sunday, 60s on Monday and 50s to lower 60s on
Tuesday. Stay tuned for forecast updates. RMS

&&

.AVIATION...

VFR conditions will prevail today. LLWS will be over southeast MT
and north central WY this morning. Surface winds have begun to
increase across western routes, including KLVM and KBIL, with
gusts in KLVM of 45 kts, and KBIL gusting to 25 kts. Strong and gusty
winds will overspread all of southeast MT through the morning,
with gusts to around 40-50 kts by this afternoon. Gusty winds
will continue into this evening. A dry cold front will bring a
wind shift later today, from west/southwest most of the morning to
northwest this afternoon and evening. Winds will decrease
tonight. Gilstad/RMS

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Thu     Fri     Sat     Sun     Mon     Tue
-------------------------------------------------------
BIL 094 051/085 053/088 058/095 056/077 049/064 039/058
    0/N 10/U    00/U    00/U    11/B    24/W    53/W
LVM 092 044/086 049/092 053/095 051/082 044/066 034/061
    0/N 00/U    00/U    00/U    11/U    24/W    43/W
HDN 094 048/083 050/088 054/096 054/077 046/064 037/057
    0/N 10/U    00/U    00/U    11/B    24/W    53/W
MLS 093 050/078 051/085 056/093 054/074 047/063 038/058
    0/N 10/U    00/U    00/U    11/U    34/W    53/W
4BQ 094 050/080 052/085 056/094 056/077 047/062 037/055
    0/N 00/U    00/U    00/U    11/U    34/W    54/W
BHK 091 046/075 048/082 053/090 051/073 044/061 035/055
    0/N 10/U    00/U    00/U    11/U    34/W    53/W
SHR 093 044/082 049/087 053/095 053/080 044/063 033/055
    0/N 00/U    00/U    00/U    11/U    35/W    65/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Red Flag Warning in effect until 6 PM MDT this evening FOR
      ZONE 117.
     Red Flag Warning in effect until midnight MDT tonight FOR
      ZONES 123>133.
WY...Red Flag Warning in effect until midnight MDT tonight FOR
      ZONES 274-284.

&&

weather.gov/billings

In the hours before

Local storm report, Sep 2, 7:39 AM MST, 3 hours 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
839 AM MDT WED SEP 02 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0720 AM     NON-TSTM WND GST 3 ENE LIVINGSTON        45.69N 110.50W
09/02/2020  M56.00 MPH       PARK               MT   DEPT OF HIGHWAYS

&&

VERTZ

Local storm report, Sep 2, 8:05 AM MST, 2 hours 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
905 AM MDT WED SEP 02 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0851 AM     NON-TSTM WND GST 6 ENE LIVINGSTON        45.70N 110.45W
09/02/2020  M55.00 MPH       PARK               MT   ASOS

&&

VERTZ

Local storm report, Sep 2, 9:07 AM MST, 1 hour 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
1007 AM MDT WED SEP 02 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0912 AM     NON-TSTM WND GST 17 NE WILSALL           46.16N 110.38W
09/02/2020  M58.00 MPH       PARK               MT   MESONET

0952 AM     NON-TSTM WND GST 6 ENE LIVINGSTON        45.70N 110.45W
09/02/2020  M63.00 MPH       PARK               MT   ASOS

&&

VERTZ

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 wildfire. Local standard time, as filed.

Wildfire, Musselshell

When: September 2, 11:00 AM MST to September 28, 5:00 PM MST
Where: Musselshell forecast zone
Reported by: County Official
Coordinates: 46.497, -108.398 (the zone’s center; the record gives no point)

The BobCat fire was detected on September 2nd on private lands approximately 7 miles southeast of Roundup east of MT Highway 87. The fire burned in tall grass, intermixed with ponderosa pine stands and sagebrush. Primarily wind-driven, the fire spread to the southeast from the origin. The total number of personnel working the fire was 104. Total acreage burned was 30,030. The Musselshell County DES reported that a structure assessment found 14 primary and 34 secondary/outbuildings were lost in the fire.

What these are

Wildfire: A fire burning in wildland vegetation, with its acreage and damage where known.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Montana in 2020 Every state in 2020 This day in weather history Warnings in Montana, September 2020

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 919027.