Montana, 2021

Hail and High Wind in Montana, June 10, 2021

June 10, 2021 · NWS TFX · 4 events in 3 counties and zones

A cold front moved across Montana on June 10, bringing a few isolated thunderstorms and gusty winds to the area. One of the thunderstorms would become severe, dropping 1 inch hail near Grass Range, MT.

Where it happened

Every event with a place to put it. 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

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
4

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 TFX wrote it up.

A cold front moved across Montana on June 10, bringing a few isolated thunderstorms and gusty winds to the area. One of the thunderstorms would become severe, dropping 1 inch hail near Grass Range, MT. In addition, winds across SW Montana were quite strong near and behind a cold front, with many reports of wind gusts in excess of 50 MPH, and a few wind gusts over 60 MPH.

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 Great Falls, MT wrote its last area forecast discussion before the first event at Jun 10, 12:14 PM MST, 39 minutes earlier.

Area forecast discussion, Jun 10, 12:14 PM MST, 39 minutes before
Area Forecast Discussion
National Weather Service Great Falls MT
114 PM MDT Thu Jun 10 2021

.SYNOPSIS...

Scattered showers and thunderstorms this afternoon will move
away to the east overnight. Temperatures remain cool on Friday
before a significant warming trend begins this weekend. Expect
widespread 90s at least next Monday and Tuesday.

&&

.DISCUSSION...

A potent upper level trough and its attendant surface front is
crossing the Continental Divide this afternoon. Observations
reveal a line of showers and thunderstorms developing over
Southwest Montana. This activity will continue to spread further
east through the evening as the trough lifts from Southwest toward
Northeast. A cool and stable airmass remains in place over North-
central Montana. Only scattered light rain showers would be
expected here until the front passes through and increasing
westerly downslope winds develop. Isolated stronger thunderstorms
are possible further east, where stability and shear profiles are
more favorable for possibly severe convection. The main concern
from any severe thunderstorms (eastern Fergus and Blaine counties)
will be gusty winds and large hail. The passing cold front will
lower snow levels to around 6000 feet, so some light snow
accumulation may be possible where precipitation lingers
overnight. Furthermore, frost is likely tonight for some of the
higher elevation Southwest valleys. Skies clear out on Friday to
start the beginning of a warming trend. PN

Saturday through next Thursday...A broad ridge of high pressure
builds across the area this weekend into at least early next week,
bringing dry conditions and significant warming. Widespread 80s
are expected by Sunday, with a few 90s possible. The peak of the
next heat wave looks to occur Monday and Tuesday Tuesday, with
afternoon temperatures in the 90s for much of the CWA, and a few
100s can't be ruled out. There is fairly good agreement that on
Wednesday a Pacific cool front will move through the region,
resulting in increased winds developing. Between the anticipated
dry nature of this front and the antecedent hot and dry weather,
fire weather concerns would be on the rise. This 'cool' front may
bring some relief from the heat for Wednesday and next Thursday,
but the degree of any cool-off remains uncertain as there is
disagreement among the deterministic models and increasing spread
in ensemble probabilities. -Kredensor

&&

.AVIATION...
1130 AM MDT Thursday Jun 10 2021 (10/18Z TAF period)

Low stratus remains over KHVR/KLWT producing IFR/MVFR conditions.
These clouds are expected to thin and mix out through late
afternoon. A cold front advancing across the Continental Divide is
helping to generate a line of thundershowers. Expect increasing
coverage of thunderstorms, likely impacting KHLN/KBZN/KEKS/KWYS
(southwest Montana terminals) around 00-03Z. Skies gradually clear
overnight, with prevailing VFR conditions on Friday.

Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  40  70  45  78 /  30   0   0   0
CTB  39  66  41  70 /  30   0   0   0
HLN  40  73  48  82 /  40   0   0   0
BZN  35  71  43  83 /  70   0   0   0
WYS  27  61  33  75 /  70   0   0   0
DLN  32  67  43  80 /  50   0   0   0
HVR  44  72  46  80 /  30   0   0   0
LWT  39  69  44  79 /  50   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Jun 10, 7:31 AM MST, 5 hours 22 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
831 AM MDT THU JUN 10 2021

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

0912 PM     HAIL             7 ENE BIG SANDY         48.21N 109.97W
06/09/2021  E2.00 INCH       CHOUTEAU           MT   PUBLIC

            PICTURES FROM A SOCIAL MEDIA POST SHOWING
            1.5 TO 2 INCH HAIL REPORTED NEAR CENTENNIAL
            MOUNTAIN AREA.

&&

TP
Local storm report, Jun 10, 9:13 AM MST, 3 hours 40 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1013 AM MDT THU JUN 10 2021

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

0720 PM     HAIL             HAYS                    47.99N 108.69W
06/09/2021  E2.50 INCH       BLAINE             MT   PUBLIC

            PUBLIC REPORT FROM HAYS, MT THAT THERE WAS
            PING PONG TO TENNIS BALL SIZE HAIL WHEN THE
            FIRST SYSTEM MOVED THROUGH.

&&

TP
Local storm report, Jun 10, 9:17 AM MST, 3 hours 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1017 AM MDT THU JUN 10 2021

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

1159 PM     HEAVY RAIN       3 S LEWISTOWN           47.03N 109.42W
06/09/2021  M0.45 INCH       FERGUS             MT   TRAINED SPOTTER

            0.45 INCHES RAIN IN AN EVENING THUNDERSTORM.

&&
Local storm report, Jun 10, 9:28 AM MST, 3 hours 25 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1028 AM MDT THU JUN 10 2021

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

1005 PM     HAIL             HAYS                    47.99N 108.70W
06/09/2021  E1.00 INCH       BLAINE             MT   PUBLIC

            QUARTER SIZE HAIL REPORTED DURING THE SECOND
            SYSTEM TO PASS OVER HAYS, MT.

&&

TP
Local storm report, Jun 10, 9:31 AM MST, 3 hours 22 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1031 AM MDT THU JUN 10 2021

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

1055 PM     HAIL             HAYS                    47.99N 108.70W
06/09/2021  E1.50 INCH       BLAINE             MT   PUBLIC

            QUARTER TO PING PONG BALL SIZED HAIL
            REPORTED IN HAYS, MT WITH THE THIRD SYSTEM
            THAT TRACKED THROUGH THE AREA, GUSTY WINDS
            THAT SHOOK THE TRUCK, ESTIMATED 50 MPH
            GUSTS.

&&

TP

The radar

The Billings radar (KBLX), 135 km away, was scanning. The volume nearest the first event began at 21:33 UTC.

Open the radar archive at this moment

Event by event

3 high wind, 1 hail. Local standard time, as filed.

High Wind, Beaverhead

When
June 10, 12:53 PM MST
Where
Beaverhead forecast zone
Measured
53 kt (61 mph) measured gust
Reported by
ASOS

ASOS reports 61 mph peak gusts recorded at the dillon airport at 1:53 pm.

High Wind, Gallatin

When
June 10, 1:15 PM MST
Where
Gallatin forecast zone
Measured
55 kt (63 mph) measured gust
Reported by
Mesonet

Mesonet station mtm07 3.2 sw amsterdam (mt-meso).

High Wind, Gallatin

When
June 10, 2:00 PM MST to 8:00 PM MST
Where
Gallatin forecast zone
Measured
57 kt (66 mph) measured gust
Reported by
Trained Spotter

Winds sustained 38 to 45 mph throughout the afternoon and evening. Regular gusts into mid 50s mph. Peak gust to 66 mph at 3pm.

Hail, Fergus

When
June 10, 2:33 PM MST
Where
Fergus County, 3.34 mi NE of Grassrange
Measured
1 in hail
Reported by
Public
Coordinates
47.060, -108.740

Report of 1 inch hail from MPING.

What these are

High Wind
Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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

The same day elsewhere

More

Every storm in Montana in 2021Every state in 2021This day in weather historyWarnings in Montana, June 2021

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: 965116, 954464, 954463, 954462.