Alert archive / Washington / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 193
The Storm Prediction Center issued this severe thunderstorm watch at May 4, 2017, 4:05 PM PDT for 7 counties in Oregon; 9 counties in Washington. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- May 4, 2017, 4:05 PM PDT (23:05 UTC)
- Expired
- May 4, 2017, 11:00 PM PDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Clackamas County, OR, Douglas County, OR, Hood River County, OR, Lane County, OR, Linn County, OR, Marion County, OR, Multnomah County, OR, Chelan County, WA, Clark County, WA, Cowlitz County, WA, Douglas County, WA, Grant County, WA, Lewis County, WA, Pierce County, WA, Skamania County, WA, Thurston County, WA
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 5%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 4:11 PM PDT | Severe Thunderstorm Warning | SEW | King, Pierce | 34 min |
| May 4, 4:14 PM PDT | Severe Thunderstorm Warning | SEW | Lewis, Thurston | 31 min |
| May 4, 4:16 PM PDT | Severe Thunderstorm Warning | PQR | Clark, Cowlitz, Skamania | 29 min |
| May 4, 4:23 PM PDT | Severe Thunderstorm Warning | SEW | Lewis | 37 min |
| May 4, 4:31 PM PDT | Severe Thunderstorm Warning | PQR | Clackamas | 29 min |
| May 4, 4:45 PM PDT | Severe Thunderstorm Warning | SEW | Pierce, Thurston | 30 min |
| May 4, 5:03 PM PDT | Severe Thunderstorm Warning | PQR | Clark, Cowlitz, Skamania | 27 min |
| May 4, 5:20 PM PDT | Severe Thunderstorm Warning | SEW | Lewis | 25 min |
| May 4, 6:15 PM PDT | Severe Thunderstorm Warning | MFR | Douglas, Jackson | 45 min |
| May 4, 6:51 PM PDT | Severe Thunderstorm Warning | MFR | Douglas, Jackson | 24 min |
| May 4, 7:20 PM PDT | Severe Thunderstorm Warning | PQR | Cowlitz, Wahkiakum | 29 min |
| May 4, 7:29 PM PDT | Severe Thunderstorm Warning | PQR | Lane | 46 min |
| May 4, 7:54 PM PDT | Severe Thunderstorm Warning | MFR | Douglas, Jackson, Klamath | 36 min |
| May 4, 8:13 PM PDT | Severe Thunderstorm Warning | MFR | Douglas, Klamath | 17 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Salem/Mcnary, OR (KSLE), launched 12:00Z, 11.1 hours before the alert went out and 193 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.
- Mixed-layer CAPE
- 6 J/kg
- Mixed-layer CIN
- -555 J/kg
- Mixed-layer LCL
- 1172 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 12 m²/s²
- 0-3 km storm-relative helicity
- 79 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 3:34 PM PDT | Mesoscale Discussion | SPC | Clackamas, Columbia, Douglas, Gilliam, Hood River, Jefferson and 8 more | 86 min |
Nearby
Severe Thunderstorm Watches in Washington, 2017Severe Thunderstorm Watches in Oregon, 2017Every severe thunderstorm watch in 2017
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.