Alert archive / California / Flash Flood Watches in 2009

Flash Flood Watch 1, NWS Reno, NV

May 31, 20097 counties in Nevada; 9 counties in California

NWS Reno, NV issued this flash flood watch at May 31, 2009, 6:43 AM PDT for 7 counties in Nevada; 9 counties in California. It took effect at May 31, 2009, 1:00 PM PDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: May 31, 2009, 6:43 AM PDT (13:43 UTC)
In effect from: May 31, 2009, 1:00 PM PDT
Expired: May 31, 2009, 6:37 PM PDT
In force: 6 hr
Issued by: NWS Reno, NV
Flood severity: None

Counties Alpine County, CA, El Dorado County, CA, Lassen County, CA, Modoc County, CA, Mono County, CA, Nevada County, CA, Placer County, CA, Plumas County, CA, Sierra County, CA, Churchill County, NV, Douglas County, NV, Lyon County, NV, Mineral County, NV, Pershing County, NV, Storey County, NV, Washoe County, NV

The radar

The Reno radar (KRGX), 39 km from the middle of the area, began a volume at 13:46 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

Reno, NV (KREV), launched 12:00Z, 1.7 hours before the alert went out and 136 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 273 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 914 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 43 m²/s²
0-3 km storm-relative helicity: 49 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 flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Reno, NV wrote its last area forecast discussion before this flash flood watch went out at May 31, 2:40 AM PDT, 4 hours 3 minutes earlier.

Area forecast discussion, May 31, 2:40 AM PDT, 4 hours 3 minutes before

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Hazardous weather outlook, May 31, 6:00 AM PDT, 43 minutes before

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In the hours before

Local storm report, May 31, 6:17 AM PDT, 26 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RENO NV
617 AM PDT SUN MAY 31 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0613 AM     HEAVY RAIN       2 SE SPANISH SPRINGS    39.65N 119.69W
05/31/2009  M0.83 INCH       WASHOE             NV   TRAINED SPOTTER

            SPOTTER REPORTED 0.83 INCHES OF RAINFALL BETWEEN 500 PM
            AND 830 PM YESTERDAY EVENING.

&&

KMOZLEY

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 5:53 PM PDT	Severe Thunderstorm Warning	REV	Douglas, Lyon	37 min
May 30, 6:31 PM PDT	Flash Flood Warning	REV	Lyon	2 hr
May 31, 12:05 PM PDT	Severe Thunderstorm Warning	REV	Washoe	25 min
May 31, 1:34 PM PDT	Severe Thunderstorm Warning	REV	Lyon, Storey	26 min

Nearby

Flash Flood Watches in California, 2009 Flash Flood Watches in Nevada, 2009 Every flash flood watch in 2009

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.