Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 13, NWS Hanford, CA

July 30, 2021Mariposa County, California

NWS Hanford, CA issued this flash flood warning at Jul 30, 2021, 4:33 PM PDT for Mariposa County, California. It was in force for 57 min. 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 30, 2021, 4:33 PM PDT (23:33 UTC)
Expired
Jul 30, 2021, 5:30 PM PDT
In force
57 min
Issued by
NWS Hanford, CA
Area
Storm-based polygon
Flood severity
None

County Mariposa County, CA

The radar

The San Joaquin Valley radar (KHNX), 158 km from the middle of the area, began a volume at 23:35 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

Oakland, CA (KOAK), launched 12:00Z, 11.6 hours before the alert went out and 230 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, Oakland, CA at 12:00Z on 2021-07-30Temperature 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, Oakland, CA at 12:00Z on 2021-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1819 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
28 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.

212 
WGUS56 KHNX 302333
FFWHNX
CAC043-310030-
/O.NEW.KHNX.FF.W.0013.210730T2333Z-210731T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Joaquin Valley CA
433 PM PDT Fri Jul 30 2021

The National Weather Service in Hanford CA has issued a

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

* Until 530 PM PDT.

* At 432 PM PDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. 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, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that will experience flooding include...
  Yosemite Valley, Yosemite Glacier Point, Yosemite Valley Vistor
  Center, North Pines Campground, Camp 4 Campground, Lower Pines
  Campground and Upper Pines Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3777 11952 3766 11958 3771 11966 3778 11964

FLASH FLOOD...RADAR INDICATED

$$

Andersen
1 follow-up statement
493 
WGUS76 KHNX 310023
FFSHNX

Flash Flood Statement
National Weather Service San Joaquin Valley CA
523 PM PDT Fri Jul 30 2021

CAC043-310033-
/O.EXP.KHNX.FF.W.0013.000000T0000Z-210731T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mariposa CA-
523 PM PDT Fri Jul 30 2021

...THE FLASH FLOOD WARNING FOR NORTHEASTERN MARIPOSA COUNTY WILL
EXPIRE AT 530 PM PDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Runoff may continue over the next hour. Please continue to 
heed any remaining road closures.

LAT...LON 3777 11952 3766 11958 3771 11966 3778 11964

$$

Andersen

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 5:20 PM PDTFlash Flood Warning Considerable damage threatHNXMadera3 hr
Jul 30, 2:52 PM PDTFlash Flood WarningHNXFresno, Madera38 min
Jul 30, 3:30 PM PDTFlash Flood WarningHNXFresno, Madera, Mariposa60 min
Jul 30, 4:02 PM PDTFlash Flood WarningHNXMariposa, Tuolumne116 min
Jul 30, 4:08 PM PDTSpecial Weather StatementHNXMariposa22 min
Jul 30, 4:20 PM PDTSpecial Weather StatementHNXTuolumne40 min
Jul 30, 4:30 PM PDTSpecial Weather StatementHNXMariposa45 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.