Alert archive / Nevada / Flash Flood Warnings in 2018

Flash Flood Warning 13, NWS Reno, NV

July 22, 2018Lyon County, Nevada

NWS Reno, NV issued this flash flood warning at Jul 22, 2018, 3:43 PM PDT for Lyon County, Nevada. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 22, 2018, 3:43 PM PDT (22:43 UTC)
Expired
Jul 22, 2018, 6:04 PM PDT
In force
2 hr
Issued by
NWS Reno, NV
Area
Storm-based polygon
Flood severity
None

County Lyon County, NV

The radar

The Reno radar (KRGX), 131 km from the middle of the area, began a volume at 22:46 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, 10.7 hours before the alert went out and 139 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, Reno, NV at 12:00Z on 2018-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 74 joules per kilogram.LCLLFCEL10008507005003002001001 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, Reno, NV at 12:00Z on 2018-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 square meters per square second.193958Sfc1 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
74 J/kg
Mixed-layer CIN
-161 J/kg
Mixed-layer LCL
1763 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

465 
WGUS55 KREV 222243
FFWREV
NVC019-230115-
/O.NEW.KREV.FF.W.0013.180722T2243Z-180723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Reno NV
343 PM PDT SUN JUL 22 2018

The National Weather Service in Reno has issued a

* Flash Flood Warning for...
  South central Lyon County in west central Nevada...

* Until 615 PM PDT.

* At 341 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Radar estimates up to 0.70 inc 
  hes of rain have fallen just east of Sweetwater Summit in the last 
  hour. Additional amounts of up to 0.50 inches are possible in the 
  next hour. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Sweetwater Summit.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 3867 11924 3866 11917 3855 11908 3845 11918
      3857 11929

$$
2 follow-up statements
220 
WGUS75 KREV 222338
FFSREV

Flash Flood Statement
National Weather Service Reno NV
438 PM PDT SUN JUL 22 2018

NVC019-230115-
/O.CON.KREV.FF.W.0013.000000T0000Z-180723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lyon NV-
438 PM PDT SUN JUL 22 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM PDT FOR
SOUTH CENTRAL LYON COUNTY...

At 437 PM PDT, light rain continues in the Sweetwater Summit area, 
but the heaviest rain has shifted to the south. Run off from recent 
heavy rains may still pose a threat of debris flows through the next 
couple of hours. 

Some locations that will experience flooding include...
Sweetwater Summit.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 3867 11924 3866 11917 3855 11908 3845 11918
      3857 11929

$$
293 
WGUS75 KREV 230104
FFSREV

Flash Flood Statement
National Weather Service Reno NV
604 PM PDT SUN JUL 22 2018

NVC019-230114-
/O.CAN.KREV.FF.W.0013.000000T0000Z-180723T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lyon NV-
604 PM PDT SUN JUL 22 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL LYON COUNTY IS
CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3867 11924 3866 11917 3855 11908 3845 11918
      3857 11929

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 6:32 PM PDTFlash Flood WarningREVWashoe2 hr
Jul 21, 6:40 PM PDTFlash Flood WarningREVPershing, Washoe2 hr
Jul 22, 8:13 AM PDTFlash Flood WatchREVDouglas, Lyon, Storey, Washoe13 hr
Jul 22, 4:59 PM PDTSevere Thunderstorm WarningREVStorey46 min

Nearby

Flash Flood Warnings in Nevada, 2018Every flash flood warning in 2018

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.