Alert archive / California / Flood Watches in 2018

Flood Watch 2, NWS Eureka, CA

April 5, 2018Humboldt County, Mendocino County, Trinity County, California

NWS Eureka, CA issued this flood watch at Apr 5, 2018, 12:25 PM PDT for Humboldt County, Mendocino County, Trinity County, California. It took effect at Apr 6, 2018, 5:00 AM PDT. It was in force for 23 hr.

The area

The counties it named.

The facts

Issued
Apr 5, 2018, 12:25 PM PDT (19:25 UTC)
In effect from
Apr 6, 2018, 5:00 AM PDT
Expired
Apr 7, 2018, 3:57 AM PDT
In force
23 hr
Issued by
NWS Eureka, CA
Flood severity
None

Counties Humboldt County, CA, Mendocino County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 73 km from the middle of the area, began a volume at 19:29 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

Medford/Jackson, OR (KMFR), launched 12:00Z, 7.4 hours before the alert went out and 241 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, Medford/Jackson, OR at 12:00Z on 2018-04-05Temperature 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, Medford/Jackson, OR at 12:00Z on 2018-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.19395878Sfc1 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
1103 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

146 
WGUS66 KEKA 051925
FFAEKA

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Eureka CA
1225 PM PDT Thu Apr 5 2018

...Moderate to heavy rain Friday and Friday night...

.A strong atmospheric river will bring wet weather to the area.
Rain has started to spread across the area this afternoon. This
will continue through early Saturday morning. The heaviest rain is
expected Friday night. There is a slight chance for main stem 
river flooding, stay tuned to the forecast. 

CAZ104-106-108>113-060330-
/O.NEW.KEKA.FA.A.0002.180406T0900Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
1225 PM PDT Thu Apr 5 2018

...FLOOD WATCH IN EFFECT FROM LATE TONIGHT THROUGH SATURDAY
MORNING...

The National Weather Service in Eureka has issued a

* Flood Watch for a portion of northwest California, including 
  the following areas, Mendocino Coast, Northeastern Mendocino 
  Interior, Northwestern Mendocino Interior, Southeastern 
  Mendocino Interior, Southern Humboldt Interior, Southern 
  Trinity, Southwestern Humboldt, and Southwestern Mendocino 
  Interior. 

* From late tonight through Saturday morning. The heaviest rain is
  expected Friday afternoon and Friday night.

* Rainfall amounts of 3 to 5 inches are expected with local 
  amounts up to 7 inches possible in the higher terrain.

* Small stream flooding will become swollen and fast moving. They
  may exceed their banks and cause flooding. Low lying areas may
  flood as well.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
6 follow-up statements
707 
WGUS66 KEKA 060328
FFAEKA

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Eureka CA
828 PM PDT Thu Apr 5 2018

...Moderate to heavy rain Friday and Friday night...

.Light to moderate rain will continue tonight. Moderate to heavy 
rain is expected Friday through early Saturday morning. The 
heaviest rain is expected Friday night. There is a slight 
potential for flooding Friday through Saturday morning. 

CAZ104-106-108>113-061230-
/O.EXT.KEKA.FA.A.0002.180406T1200Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
828 PM PDT Thu Apr 5 2018

...FLOOD WATCH NOW IN EFFECT FROM 5 AM PDT FRIDAY THROUGH
SATURDAY MORNING...

The Flood Watch is now in effect for

* A portion of northwest California, including the following 
  areas, Mendocino Coast, Northeastern Mendocino Interior, 
  Northwestern Mendocino Interior, Southeastern Mendocino 
  Interior, Southern Humboldt Interior, Southern Trinity, 
  Southwestern Humboldt, and Southwestern Mendocino Interior. 

* From late tonight through Saturday morning. The heaviest rain is
  expected Friday afternoon and Friday night.

* Rainfall amounts of 3 to 5 inches are expected with local 
  amounts up to 7 inches possible in the higher terrain.

* Small streams will become swollen and fast moving. They may 
  exceed their banks and cause flooding. Low lying areas and rural
  roads may also flood.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
038 
WGUS66 KEKA 060951
FFAEKA

Flood Watch
National Weather Service Eureka CA
251 AM PDT Fri Apr 6 2018

...Moderate to heavy rain through tonight...

.Light to moderate rain will increase in intensity this morning. 
Moderate to heavy rain is expected this morning through early 
Saturday morning. The heaviest rain is expected tonight. There is
a slight potential for flooding through Saturday morning.

CAZ104-106-108>113-061800-
/O.CON.KEKA.FA.A.0002.180406T1200Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
251 AM PDT Fri Apr 6 2018

...FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY MORNING...

The Flood Watch continues for

* A portion of northwest California, including the following 
  areas, Mendocino Coast, Northeastern Mendocino Interior, 
  Northwestern Mendocino Interior, Southeastern Mendocino 
  Interior, Southern Humboldt Interior, Southern Trinity, 
  Southwestern Humboldt, and Southwestern Mendocino Interior. 

* Through Saturday morning

* Rainfall amounts of 3 to 5 inches are expected with local
  amounts up to 7 inches possible in higher terrain. 

* Small streams will become swollen and fast moving. They may 
  exceed their banks and cause flooding. Low lying areas and 
  rural roads may also flood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
621 
WGUS66 KEKA 061357
FFAEKA

Flood Watch
National Weather Service Eureka CA
657 AM PDT Fri Apr 6 2018

.An atmospheric river will bring potential flooding through 
Saturday to small streams as well as low lying areas with poor 
drainage. In addition, there is a slightly enhanced potential for 
debris flow in the Redwood Valley Burn Scar area in the heaviest 
persistent showers.

CAZ104-106-108>113-062200-
/O.CON.KEKA.FA.A.0002.000000T0000Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
657 AM PDT Fri Apr 6 2018

...FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY MORNING...

The Flood Watch continues for

* A portion of northwest California, including the following 
  areas, Mendocino Coast, Northeastern Mendocino Interior, 
  Northwestern Mendocino Interior, Southeastern Mendocino 
  Interior, Southern Humboldt Interior, Southern Trinity, 
  Southwestern Humboldt, and Southwestern Mendocino Interior. 

* Through Saturday morning

* Rainfall amounts of 3 to 5 inches are expected with local 
  amounts up to 7 inches possible in higher terrain. 

* Small streams will become swollen and fast moving. They may 
  exceed their banks and cause flooding. Low lying areas and 
  rural roads may also flood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
412 
WGUS66 KEKA 062035
FFAEKA

Flood Watch
National Weather Service Eureka CA
135 PM PDT Fri Apr 6 2018

.Heavy rain is expected to continue through early Saturday morning
across much of the region, and is expected to cause small stream
and urban flooding in many areas. In addition, there is a 
slightly enhanced potential for debris flow in the Redwood Valley 
Burn Scar area in the heaviest persistent showers.

CAZ104-106-108>113-070445-
/O.CON.KEKA.FA.A.0002.000000T0000Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
135 PM PDT Fri Apr 6 2018

...FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY MORNING...

The Flood Watch continues for

* A portion of northwest California, including Southern Humboldt,
  Southern Trinity and most of Mendocino Counties. The heaviest
  total accumulations and most widespread impacts are expected
  across Western and Northern Mendocino County.

* Through Saturday morning

* ADDITIONAL rainfall accumulations of 3 to 4 inches are expected,
  with hourly rainfall rates reaching .5 inches per hour at times
  overnight Friday. STORM TOTAL rainfall amounts, some of which 
  has already fallen, will likely range from 5 to 7 inches across 
  a broad area. 

* Small streams will become swollen and fast moving. They may
  exceed their banks and cause flooding. Low lying areas and both rural
  and urban roads may also flood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
461 
WGUS66 KEKA 070350
FFAEKA

Flood Watch
National Weather Service Eureka CA
850 PM PDT Fri Apr 6 2018

.Heavy rain is expected to continue through early Saturday
morning and is expected to cause small stream and urban flooding 
in many areas. In addition, there is a slightly enhanced potential
for debris flow in the Redwood Valley Burn Scar area in the 
heaviest persistent showers.

CAZ104-106-108>113-071200-
/O.CON.KEKA.FA.A.0002.000000T0000Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
850 PM PDT Fri Apr 6 2018

...FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY MORNING...

The Flood Watch continues for

* A portion of northwest California, including the following 
  areas, Mendocino Coast, Northeastern Mendocino Interior, 
  Northwestern Mendocino Interior, Southeastern Mendocino 
  Interior, Southern Humboldt Interior, Southern Trinity, 
  Southwestern Humboldt, and Southwestern Mendocino Interior. 

* Through Saturday morning

* ADDITIONAL rainfall accumulations of 3 to 4 inches are expected,
  with hourly rainfall rates reaching .5 inches per hour at times
  tonight. STORM TOTAL rainfall amounts, some of which has 
  already fallen, will likely range from 5 to 7 inches across a 
  broad area. 

* Small streams will become swollen and fast moving. They may 
  exceed their banks and cause flooding. Low lying areas and 
  both rural and urban roads may also flood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Watch means there is a potential for flooding based on
current forecasts.

You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

&&

$$
729 
WGUS66 KEKA 071057
FFAEKA

Flood Watch
National Weather Service Eureka CA
357 AM PDT Sat Apr 7 2018

CAZ104-106-108>113-071200-
/O.CAN.KEKA.FA.A.0002.000000T0000Z-180407T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
357 AM PDT Sat Apr 7 2018

...FLOOD WATCH IS CANCELLED...

The Flood Watch for a portion of northwest California has been
cancelled. Heavy rain has exited the region, and the threat for
small stream flooding will quickly diminish during Saturday
morning.

$$

Nearby

Flood Watches in California, 2018Every flood watch 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.