Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS Hanford, CA

July 31, 2021Kern County, California

NWS Hanford, CA issued this flash flood warning at Jul 31, 2021, 4:08 PM PDT for Kern County, California. 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 31, 2021, 4:08 PM PDT (23:08 UTC)
Expired
Jul 31, 2021, 6:30 PM PDT
In force
2 hr
Issued by
NWS Hanford, CA
Area
Storm-based polygon
Flood severity
None

County Kern County, CA

The radar

The Edwards AFB radar (KEYX), 84 km from the middle of the area, began a volume at 23:12 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

Vandenberg AFB, CA (KVBG), launched 12:00Z, 11.1 hours before the alert went out and 242 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, Vandenberg AFB, CA at 12:00Z on 2021-07-31Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Vandenberg AFB, CA at 12:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1862 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

943 
WGUS56 KHNX 312308
FFWHNX
CAC029-010030-
/O.NEW.KHNX.FF.W.0014.210731T2308Z-210801T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Joaquin Valley CA
408 PM PDT Sat Jul 31 2021

The National Weather Service in Hanford CA has issued a

* Flash Flood Warning for...
  Northeastern Kern County in central California...

* Until 530 PM PDT.

* At 404 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between three quarters to one 
  inch of rain has fallen over the last hour. Flash flooding is 
  ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, highways, as well 
           as other drainage and low lying areas.

* Some locations that will experience flooding include...
  Onyx, and state route 178 east of of Onyx.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 3575 11810 3571 11805 3568 11805 3562 11811
      3563 11817 3568 11818 3572 11816 3574 11814

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...one half to one inches IN the next hour.
$$

CMc
2 follow-up statements
074 
WGUS56 KHNX 010018
FFWHNX
CAC029-010130-
/O.EXT.KHNX.FF.W.0014.000000T0000Z-210801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Joaquin Valley CA
518 PM PDT Sat Jul 31 2021

The National Weather Service in Hanford CA has extended the

* Flash Flood Warning for...
  Northeastern Kern County in central California...

* Until 630 PM PDT.

* At 512 PM PDT, Doppler radar indicated additional thunderstorms 
  producing heavy rain moving into the warning area. Between one to 
  one and a half inches of rain has already fallen over the last 
  hour. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, highways, as well 
           as other drainage and low lying areas.

* Some locations that will experience flooding include...
  Onyx and state route 178 east of of Onyx.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Remain alert for flooding even in locations not receiving rain.
Arroyos, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.

&&

LAT...LON 3575 11810 3571 11805 3568 11805 3562 11811
      3563 11817 3568 11818 3572 11816 3574 11814

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...one half to one inches IN the next hour.

$$

CMc
209 
WGUS76 KHNX 010121
FFSHNX

Flash Flood Statement
National Weather Service San Joaquin Valley CA
621 PM PDT Sat Jul 31 2021

CAC029-010130-
/O.EXP.KHNX.FF.W.0014.000000T0000Z-210801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kern CA-
621 PM PDT Sat Jul 31 2021

...THE FLASH FLOOD WARNING FOR NORTHEASTERN KERN COUNTY WILL EXPIRE
AT 630 PM PDT... 

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

LAT...LON 3575 11810 3571 11805 3568 11805 3562 11811
      3563 11817 3568 11818 3572 11816 3574 11814

$$

CMc

The office that day

Everything else NWS Hanford, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 31, 12:59 PM PDTSpecial Weather StatementHNXMariposa46 min
Jul 31, 2:01 PM PDTSpecial Weather StatementHNXMadera44 min

Nearby

Flash Flood Warnings in California, 2021Every flash flood warning in 2021

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.