Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

August 3, 2021

NWS Missoula, MT issued this special weather statement at Aug 3, 2021, 8:55 PM MDT. It was in force for 65 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 3, 2021, 8:55 PM MDT (02:55 UTC)
Expired
Aug 3, 2021, 10:00 PM MDT
In force
65 min
Issued by
NWS Missoula, MT
Hail
0.00 in
Wind
40

The radar

The Pendleton radar (KPDT), 187 km from the middle of the area, began a volume at 02:58 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, 2.9 hours before the alert went out and 208 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 2021-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 819 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 2021-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 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
819 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
3167 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

946 
WWUS85 KMSO 040255
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
755 PM PDT Tue Aug 3 2021
 
IDZ006-008-040400-
Southern Clearwater Mountains ID-
Lower Hells Canyon/Salmon River Region ID-
755 PM PDT Tue Aug 3 2021

...A strong thunderstorm will impact portions of southwestern Idaho
County through 900 PM PDT...

At 754 PM PDT, Doppler radar was tracking a strong thunderstorm 8
miles south of Imnaha, or 23 miles east of Enterprise, moving east at
20 mph.

HAZARD...Winds in excess of 40 mph.

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...

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 4532 11668 4542 11659 4544 11659 4547 11656
      4551 11656 4555 11652 4558 11648 4560 11646
      4566 11650 4573 11610 4517 11606 4520 11631
      4527 11634 4527 11668
TIME...MOT...LOC 0254Z 264DEG 15KT 4544 11680 

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 4, 1:21 PM MDTRed Flag WarningMSOBeaverhead, Deer Lodge, Flathead, Granite, Jefferson, Lewis and Clark and 7 more35 hr
Aug 4, 3:57 PM MDTSpecial Weather StatementMSOPowell48 min
Aug 4, 5:30 PM MDTSpecial Weather StatementMSOFlathead30 min
Aug 4, 5:35 PM MDTSpecial Weather StatementMSOLake25 min
Aug 4, 5:50 PM MDTSpecial Weather StatementMSOLake25 min
Aug 4, 5:55 PM MDTSpecial Weather StatementMSOFlathead35 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.