Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 18, NWS Las Vegas, NV

July 19, 2017San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 19, 2017, 7:53 AM PDT for San Bernardino County, California. It was in force for 3 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 19, 2017, 7:53 AM PDT (14:53 UTC)
Expired
Jul 19, 2017, 10:45 AM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 101 km from the middle of the area, began a volume at 14:55 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

Las Vegas, NV (KVEF), launched 12:00Z, 2.9 hours before the alert went out and 177 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, Las Vegas, NV at 12:00Z on 2017-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 539 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, Las Vegas, NV at 12:00Z on 2017-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -39 square meters per square second.1939Sfc1 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
539 J/kg
Mixed-layer CIN
-200 J/kg
Mixed-layer LCL
2329 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-39 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

590 
WGUS55 KVEF 191453
FFWVEF
CAC071-191745-
/O.NEW.KVEF.FF.W.0018.170719T1453Z-170719T1745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
753 AM PDT WED JUL 19 2017

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  Eastern San Bernardino County in southern California...

* Until 1045 AM PDT

* At 751 AM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain on National Trails Highway just west of Essex. Flash 
  flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Essex...National Trails Highway...Route 66 south of Fenner.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 3486 11506 3480 11505 3473 11525 3483 11527

$$

Morgan
2 follow-up statements
199 
WGUS75 KVEF 191629
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
929 AM PDT WED JUL 19 2017

CAC071-191745-
/O.CON.KVEF.FF.W.0018.000000T0000Z-170719T1745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
929 AM PDT WED JUL 19 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 AM PDT FOR
EASTERN SAN BERNARDINO COUNTY...

At 924 AM PDT, Doppler radar indicated the heavy rain has diminished 
but runoff and flooding from the earlier rain is expected through 
1045 AM PDT. 

Some locations that will experience flooding include...
Essex.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 3486 11506 3480 11505 3473 11525 3483 11527

$$

Czyzyk
442 
WGUS75 KVEF 191738
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1038 AM PDT WED JUL 19 2017

CAC071-191746-
/O.EXP.KVEF.FF.W.0018.000000T0000Z-170719T1745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
1038 AM PDT WED JUL 19 2017

...THE FLASH FLOOD WARNING FOR EASTERN SAN BERNARDINO COUNTY WILL
EXPIRE AT 1045 AM PDT...

The heavy rain has ended and any flood waters should have receded. 
Therefore the flash flood warning will be allowed to expire at 1045 
AM PDT. Please continue to heed any remaining road closures.

LAT...LON 3486 11506 3480 11505 3473 11525 3483 11527

$$

Czyzyk

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 6:01 PM PDTFlash Flood WarningVEFSan Bernardino3 hr
Jul 18, 7:58 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Jul 19, 8:53 AM PDTFlash Flood WarningVEFSan Bernardino3 hr
Jul 19, 9:57 AM PDTFlash Flood WarningVEFSan Bernardino3 hr

Nearby

Flash Flood Warnings in California, 2017Every flash flood warning 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; radar from the NEXRAD Level II archive.