Alert archive / Washington / Special Weather Statements in 2021

Special Weather Statement, NWS Spokane, WA

August 3, 2021

NWS Spokane, WA issued this special weather statement at Aug 3, 2021, 6:17 PM PDT. It was in force for 73 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, 6:17 PM PDT (01:17 UTC)
Expired
Aug 3, 2021, 7:30 PM PDT
In force
73 min
Issued by
NWS Spokane, WA

The radar

The Seattle radar (KATX), 136 km from the middle of the area, began a volume at 01:20 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

Quillayute State, WA (KUIL), launched 00:00Z, 1.3 hours before the alert went out and 286 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, Quillayute State, WA at 00:00Z on 2021-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Quillayute State, WA at 00:00Z on 2021-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.1939Sfc1 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
1439 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

399 
WWUS86 KOTX 040117
SPSOTX

Special Weather Statement
National Weather Service Spokane WA
617 PM PDT Tue Aug 3 2021
 
WAZ042-040230-
East Slopes Northern Cascades WA-
617 PM PDT Tue Aug 3 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL CHELAN AND WEST
CENTRAL OKANOGAN COUNTIES UNTIL 730 PM PDT...

At 615 PM PDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Stehekin, or 38 miles east of Darrington, moving
northeast at 20 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm. Winds could also cause damage to trees or tree limbs

Locations impacted include...
Washington Pass, Klipchuck Campground, Rattlesnake Campground, Rivers
Bend Campground, Lone Fir Campground, Ballard Campground and Harts
Pass Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also possible 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.

&&

LAT...LON 4853 12082 4851 12080 4853 12071 4858 12069
      4859 12072 4858 12076 4860 12078 4869 12071
      4869 12069 4872 12067 4860 12043 4828 12082
      4835 12094
TIME...MOT...LOC 0115Z 218DEG 16KT 4838 12080 

$$

COTE

The office that day

Everything else NWS Spokane, WA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 3, 6:13 PM PDTSpecial Weather StatementOTXDouglas62 min
Aug 3, 6:58 PM PDTSpecial Weather StatementOTXDouglas62 min
Aug 3, 8:12 PM PDTSpecial Weather StatementOTXOkanogan78 min
Aug 4, 1:53 PM PDTRed Flag WarningOTX31 hr
Aug 3, 10:57 PM PDTSpecial Weather StatementOTXLatah48 min

Nearby

Special Weather Statements in Washington, 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.