Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

August 5, 2021

NWS Missoula, MT issued this special weather statement at Aug 5, 2021, 8:08 PM MDT. It was in force for 52 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 5, 2021, 8:08 PM MDT (02:08 UTC)
Expired
Aug 5, 2021, 9:00 PM MDT
In force
52 min
Issued by
NWS Missoula, MT
Hail
0.00 in
Wind
40

The radar

The Pendleton radar (KPDT), 197 km from the middle of the area, began a volume at 02:08 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

Boise Airport, ID (KBOI), launched 00:00Z, 2.1 hours before the alert went out and 206 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, Boise Airport, ID at 00:00Z on 2021-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 484 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, Boise Airport, ID at 00:00Z on 2021-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 square meters per square second.19395878Sfc1 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
484 J/kg
Mixed-layer CIN
-147 J/kg
Mixed-layer LCL
3441 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

As transmitted.

125 
WWUS85 KMSO 060208
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
708 PM PDT Thu Aug 5 2021
 
IDZ006-008-060300-
Southern Clearwater Mountains ID-
Lower Hells Canyon/Salmon River Region ID-
708 PM PDT Thu Aug 5 2021

...A strong thunderstorm will impact portions of southwestern Idaho
County through 800 PM PDT...

At 707 PM PDT, Doppler radar was tracking a strong thunderstorm 9
miles south of Riggins, or 29 miles northwest of McCall, moving
northeast at 20 mph.

HAZARD...Winds in excess of 40 mph. Small hail. Heavy downpours 
         causing localized excess runoff. 

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects.

Locations impacted include...
Riggins, Pollock, Slate Creek, Riggins Hot Spring and Lucile. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also occurring with this storm and may lead to 
localized flooding. Do not drive your vehicle through flooded 
roadways.

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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4570 11639 4551 11591 4519 11630 4527 11634
      4527 11655 4528 11658
TIME...MOT...LOC 0207Z 211DEG 18KT 4529 11638 

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 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, 9:12 PM MDTSpecial Weather StatementMSO48 min
Aug 6, 1:13 AM MDTSpecial Weather StatementMSORavalli47 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.