Tornadoes · United States · Washington · 2018

EF2 tornado, Port Orchard, Washington, December 18, 2018

This EF2 tornado ran 1.4 miles across Kitsap County on December 18, 2018, touching down at 1:50 PM PST and reaching 285 yards wide. It killed nobody, and did $1.2 million of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mphthis tornado

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF2
Date
December 18, 2018
Touchdown
1:50 PM PST (21:50 UTC)
Lifted
1:55 PM PST (21:55 UTC)
On the ground
5 minutes
Path length
1.4 miles (2.2 km)
Path width
285 yards (261 m)
Deaths
0
Injuries
0
Property damage
$1.2 million
County
Kitsap County
Touchdown point
47.507, -122.639
Lift-off point
47.518, -122.616
Record number
1812181550-01

What the Weather Service recorded

In the wake of heavy rain, a cold unstable air mass resulted in isolated strong thunderstorms during the afternoon of December 18, 2018. The strongest storm developed over Kitsap County, WA, ultimately producing an EF-2 tornado.

At 1350PST, a tornado touched down near Port Orchard, WA. This tornado continued on the ground in a northeast direction for approximately 5 minutes. Significant structure damage was evident in the damage path, including one home where the roof was completely removed. Ultimately, 300 homes and businesses were impacted by the tornado. It resulted in 25 red-tagged (uninhabitable), and 20 yellow-tagged (habitable at own risk) homes.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 19:45 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Quillayute State, WA (KUIL), 12:00Z

9.8 hours before the tornado, 148 km from the path. December 18, 2018.

Skew-T log-pSkew-T log-p diagram, Quillayute State, WA at 12:00Z on 2018-12-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 116 joules per kilogram, CIN -1, lifted condensation level 471 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Quillayute State, WA at 12:00Z on 2018-12-18The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 227 square meters per square second, 0 to 6 km bulk shear 76 knots.1939587897117Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
116 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
76 J/kg
Mixed-layer LCL
471 m above ground
0-6 km bulk shear
76 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
227 m²/s²
0-3 km storm-relative helicity
243 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

Quillayute State, WA (KUIL), 00:00Z

2.2 hours after it, 148 km from the path. December 19, 2018.

Skew-T log-pSkew-T log-p diagram, Quillayute State, WA at 00:00Z on 2018-12-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 51 joules per kilogram, CIN -15, lifted condensation level 808 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Quillayute State, WA at 00:00Z on 2018-12-19The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 142 square meters per square second, 0 to 6 km bulk shear 46 knots.1939587897117Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
51 J/kg
Mixed-layer CIN
-15 J/kg
Surface CAPE
85 J/kg
Mixed-layer LCL
808 m above ground
0-6 km bulk shear
46 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
142 m²/s²
0-3 km storm-relative helicity
160 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
7.0 K/km

Open this sounding in Storm Lab

The radar

The Seattle radar (KATX), 76 km away, was scanning. The volume nearest the touchdown began at 21:51 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
21:50 UTCTORNADO -22 S Port OrchardKitsap Wa, NWS SEATTLE DAMAGE SURVEY CONFIRMS EF-2 TORNADO JUST SOUTH OF PORT ORCHARD. SIGNIFICANT DAMAGE TO TREES AND STRUCTURES WAS NOTED. MAX ESTIMATED WINDS 120-130 MPH. PATH LENGTH 1.4 MILES. MAX WIDTH 250-300 YARDS.
21:50 UTCTORNADO2 S Port OrchardKitsap, WANWS SEATTLE DAMAGE SURVEY CONFIRMS EF-2 TORNADO JUST SOUTH OF PORT ORCHARD. SIGNIFICANT DAMAGE TO TREES AND STRUCTURES WAS NOTED. MAX ESTIMATED WINDS 120-130 MPH. PATH LENGTH 1.4 MILES. MAX WIDTH 250-300 YARDS.
21:50 UTCTORNADO2 S Port OrchardKitsap, WATORNADO CONFIRMED VIA VIDEO, HOWEVER STRENGTH TO BE DETERMINED THROUGH SURVEY PLANNED FOR WEDNESDAY, DECEMBER 19TH.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2018 tornado in WashingtonEvery tornado in Washington since 1950Warnings in force in Washington nowThe forecast where you are

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.