Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

August 6, 2021Ravalli County, Montana

NWS Missoula, MT issued this special weather statement at Aug 6, 2021, 1:13 AM MDT for Ravalli County, Montana. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 6, 2021, 1:13 AM MDT (07:13 UTC)
Expired
Aug 6, 2021, 2:00 AM MDT
In force
47 min
Issued by
NWS Missoula, MT
Hail
0.25 in
Wind
30

County Ravalli County, MT

The radar

The Missoula radar (KMSX), 151 km from the middle of the area, began a volume at 07:15 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 7.2 hours before the alert went out and 294 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Spokane, WA at 00:00Z on 2021-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2021-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -14 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2910 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-14 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

621 
WWUS85 KMSO 060713
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
113 AM MDT Fri Aug 6 2021
 
IDZ009-010-MTZ005-006-060800-
Eastern Lemhi County ID-Western Lemhi County ID-
Bitterroot/Sapphire Mountains MT-Missoula/Bitterroot Valleys MT-
113 AM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of northern Lemhi and
southeastern Ravalli Counties through 200 AM MDT...

At 112 AM MDT, Doppler radar was tracking a strong thunderstorm near
Gibbonsville, or 32 miles north of Salmon, moving north at 25 mph.

HAZARD...Winds in excess of 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

Locations impacted include...
Gibbonsville, Sula and Lost Trail Pass. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4575 11382 4575 11385 4578 11387 4575 11391
      4570 11391 4570 11394 4567 11393 4565 11390
      4563 11390 4562 11389 4562 11385 4560 11382
      4546 11388 4550 11413 4590 11409 4584 11371
TIME...MOT...LOC 0712Z 195DEG 22KT 4564 11397 

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

$$

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 5, 6:21 PM MDTSpecial Weather StatementMSOPowell39 min
Aug 5, 8:08 PM MDTSpecial Weather StatementMSO52 min
Aug 5, 9:12 PM MDTSpecial Weather StatementMSO48 min
Aug 6, 2:46 PM MDTFire Weather WatchMSOBeaverhead, Deer Lodge, Granite, Jefferson, Madison, Powell and 1 more22 hr
Aug 5, 9:20 PM MDTSpecial Weather StatementMSOIdaho40 min
Aug 5, 9:24 PM MDTSpecial Weather StatementMSOClearwater36 min
Aug 5, 9:38 PM MDTSpecial Weather StatementMSOIdaho52 min
Aug 6, 5:32 PM MDTSpecial Weather StatementMSOLemhi43 min

Nearby

Special Weather Statements in Montana, 2021Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.