Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS Hanford, CA

July 28, 2021Madera County, Mariposa County, Tuolumne County, California

NWS Hanford, CA issued this flash flood warning at Jul 28, 2021, 5:23 PM PDT for Madera County, Mariposa County, Tuolumne County, California. It was in force for 82 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 28, 2021, 5:23 PM PDT (00:23 UTC)
Expired: Jul 28, 2021, 6:45 PM PDT
In force: 82 min
Issued by: NWS Hanford, CA
Area: Storm-based polygon
Flood severity: None

Counties Madera County, CA, Mariposa County, CA, Tuolumne County, CA

The radar

The San Joaquin Valley radar (KHNX), 161 km from the middle of the area, began a volume at 00:23 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 00:00Z, 0.4 hours before the alert went out and 227 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: 16 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 3287 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 60 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

208 
WGUS56 KHNX 290023
FFWHNX
CAC039-043-109-290145-
/O.NEW.KHNX.FF.W.0005.210729T0023Z-210729T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Joaquin Valley CA
523 PM PDT Wed Jul 28 2021

The National Weather Service in Hanford CA has issued a

* Flash Flood Warning for...
  Northeastern Mariposa County in central California...
  Southeastern Tuolumne County in northern California...
  Northeastern Madera County in central California...

* Until 645 PM PDT.

* At 522 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the higher elevations of Yosemite National Park. 
  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 and 
           low lying areas.

* Some locations that will experience flooding include...
  Merced Lake High Sierra Camp, Morraine Dome Campground, Vogelsang
  High Sierra Camp, Sunrise High Sierra Camp and Merced Lake Ranger
  Station.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3788 11938 3780 11928 3772 11938 3767 11932
      3761 11943 3769 11948 3777 11951

FLASH FLOOD...RADAR INDICATED

$$

KD

1 follow-up statement

517 
WGUS76 KHNX 290053
FFSHNX

Flash Flood Statement
National Weather Service San Joaquin Valley CA
553 PM PDT Wed Jul 28 2021

CAC039-043-109-290145-
/O.CON.KHNX.FF.W.0005.000000T0000Z-210729T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mariposa CA-Tuolumne CA-Madera CA-
553 PM PDT Wed Jul 28 2021

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM PDT FOR
NORTHEASTERN MARIPOSA...SOUTHEASTERN TUOLUMNE AND NORTHEASTERN MADERA
COUNTIES...

At 551 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. Moderate to heavy
rain will continue for the next 30 minutes or so with an additionl
half inch to three quarters of an inch possible. 

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...
Merced Lake High Sierra Camp, Morraine Dome Campground, Vogelsang
High Sierra Camp, Sunrise High Sierra Camp and Merced Lake Ranger
Station.

Additional rainfall amounts of up to three quarters of an inch 
is possible in the warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3788 11938 3780 11928 3772 11938 3767 11932
      3761 11943 3769 11948 3777 11951

FLASH FLOOD...RADAR INDICATED

$$

KD

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 5:07 PM PDT	Flash Flood Warning	HNX	Madera, Mariposa, Tuolumne	3 min
Jul 28, 7:00 PM PDT	Special Weather Statement	HNX	Tulare	45 min
Jul 29, 9:38 AM PDT	Flash Flood Watch	HNX		58 hr
Jul 29, 1:51 PM PDT	Special Weather Statement	HNX	Mariposa	39 min
Jul 29, 1:52 PM PDT	Special Weather Statement	HNX	Mariposa	38 min
Jul 29, 2:03 PM PDT	Flash Flood Warning	HNX	Madera, Mariposa	117 min
Jul 29, 2:24 PM PDT	Special Weather Statement	HNX	Tuolumne	36 min
Jul 29, 3:07 PM PDT	Special Weather Statement	HNX	Mariposa	38 min
Jul 29, 3:21 PM PDT	Flash Flood Warning	HNX	Mariposa, Tuolumne	84 min
Jul 29, 3:46 PM PDT	Flash Flood Warning	HNX	Mariposa	119 min
Jul 29, 4:41 PM PDT	Areal Flood Advisory	HNX	Mariposa, Tuolumne	64 min

Nearby

Flash Flood Warnings in California, 2021 Every 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.