Alert archive / Washington / Flood Watches in 2011

Flood Watch 8, NWS Seattle, WA

April 1, 2011King County, Washington

NWS Seattle, WA issued this flood watch at Apr 1, 2011, 8:21 AM PDT for King County, Washington. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Apr 1, 2011, 8:21 AM PDT (15:21 UTC)
Expired
Apr 1, 2011, 8:21 PM PDT
In force
12 hr
Issued by
NWS Seattle, WA
Flood severity
None

County King County, WA

The radar

The Seattle radar (KATX), 92 km from the middle of the area, began a volume at 15:22 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

Spokane, WA (KOTX), launched 12:00Z, 3.4 hours before the alert went out and 408 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, Spokane, WA at 12:00Z on 2011-04-01Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 2011-04-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 square meters per square second.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.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1890 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Seattle, WA wrote its last area forecast discussion before this flood watch went out at Apr 1, 2:50 AM PDT, 5 hours 31 minutes earlier.

Area forecast discussion, Apr 1, 2:50 AM PDT, 5 hours 31 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 1, 2:51 AM PDTSmall Craft AdvisorySEW48 hr
Apr 1, 9:17 AM PDTSmall Craft Advisory for WindsSEW36 hr

Nearby

Flood Watches in Washington, 2011Every flood watch in 2011

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.