Alert archive / California / Special Weather Statements in 2017

Special Weather Statement, NWS Eureka, CA

June 25, 2017Trinity County, California

NWS Eureka, CA issued this special weather statement at Jun 25, 2017, 4:37 PM PDT for Trinity County, California. It was in force for 38 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
Jun 25, 2017, 4:37 PM PDT (23:37 UTC)
Expired
Jun 25, 2017, 5:15 PM PDT
In force
38 min
Issued by
NWS Eureka, CA

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 109 km from the middle of the area, began a volume at 23:38 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, 11.6 hours before the alert went out and 155 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 2017-06-25Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 12:00Z on 2017-06-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
2576 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
61 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Eureka, CA wrote its last area forecast discussion before this special weather statement went out at Jun 25, 3:11 PM PDT, 1 hour 26 minutes earlier.

Area forecast discussion, Jun 25, 3:11 PM PDT, 1 hour 26 minutes before
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
311 PM PDT Sun Jun 25 2017

.SYNOPSIS...Isolated thunderstorms will continue through the
remainder of the afternoon across portions of the mountainous
interior...particularly Trinity county. This will again be
possible near the Trinity horn tomorrow and Tuesday afternoon. Hot
temperatures will cool back to near normal values tomorrow through
the remainder of the week.

&&

.DISCUSSION...After several days in a row of well above normal
temperatures throughout the area, a pattern shift is underway that
will provide relief for a large portion of Northwest California.
Just offshore an upper level low pressure system is slowly
approaching the coast, and as a result, the upper level ridge that
has persisted along the west coast is beginning to weaken.
Temperatures today will end up falling only a few degrees cooler
than previous days, but Monday and beyond will see high
temperatures fall into the 80s and 90s...a bit more tolerable and
closer to normal. Meanwhile along the coast, a steadily deepening
marine layer has allowed stratus to move farther into coastal
valleys, and has persisted much of the afternoon in many areas.
This is expected to continue for the next several days, with
cloudy drizzly nights and a slow dissipation of clouds during the
late morning and afternoon hours.

As for thunderstorms, the previously mentioned upper low has
brought southerly flow and increased mid-level moisture to the
region. As a result, thunderstorms have begun to fire early this
morning across Siskiyou county, and as of 3 PM are beginning to
develop across parts of Trinity county as well. These showers will
likely be capable of producing cloud to ground lightning strikes
and perhaps some gusty winds. However, dry sub-cloud layers will
likely result in significant rainfall evaporation, and many
valleys will not likely see much rain if any. Thunderstorms will
again be possible near the Trinity Horn Monday and Tuesday
afternoons, but most of this activity will be focused farther to
the north and east. Dry conditions will prevail through the
remainder of the week.

&&

.AVIATION...Very widespread marine stratus this morning that
stretched from WA/OR border all the way down to the Bay Area and
point south. FOr us in the Redwood Coast, the stratus hangs around
in KCEC and KACV throughout the day. Both locations were reporting
LIFR this morning. Conditions gradually improved to MVFR/IFR.
However, do not expect the improved conditions to last long. With
continuing SW-ly onshore flow, that is going to bring in a deeper
marine layer into the area. Do expect conditions to worsen to
IFR/LIFR this evening, and then gradually improve tomorrow morning.
KUKI should stay VFR overnight, but there is a potential where some
stratus can sneak in overnight and potentially lower the conditions
down to MVFR. It will be back up to VFR during the day for KUKI.

&&

.MARINE...Light winds and low seas into Monday. A trough of low
pressure remains off the coast of California through tomorrow. This
allows the pressure gradient to remain relaxed. Do expect light
winds and resultant low seas through Monday.

We will return to a strong northerly wind regime starting on Tuesday
as the East Pacific High re-establishes itself. With tight northerly
pressure gradient, the strong northerly wind regime will persist
through most of the week. Gale force wind gusts will be likely
starting middle of the work week.

Forecast is still on track. Little changes were made to the previous
forecast package. GFS is used to update the forecast package.

&&

.FIRE WEATHER...Isolated to scattered thunderstorms have developed
across Siskiyou county this afternoon, and a few are beginning to
develop across central Trinity county as of 3 PM as well. This
activity is expected to continue to mature through the remainder
of the afternoon, with isolated lightning strikes and erratic
gusty winds expected. Dry sub-cloud layers will also limit the
amount of rain that reaches the lower elevations as well. However,
fuels remain marginal for large fire growth in the northwestern
mountains at this time...although fuels have dried considerably
over the past week. Isolated storms will be possible again
tomorrow afternoon and Tuesday afternoon near the Trinity Horn.
/BRC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&

Visit us at http://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
http://www.facebook.com/NWSEureka
http://www.twitter.com/nwseureka

For forecast zone information
see the forecast zone map online:
http://www.weather.gov/eureka/zonemap.png
Hazardous weather outlook, Jun 25, 2:57 PM PDT, 1 hour 40 minutes before
Hazardous Weather Outlook
National Weather Service Eureka CA
257 PM PDT Sun Jun 25 2017

CAZ102-105-107-108-111-262200-
Del Norte Interior-Northern Humboldt Interior-Northern Trinity-
Southern Trinity-Northeastern Mendocino Interior-
257 PM PDT Sun Jun 25 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...This afternoon and tonight.

Isolated thunderstorms are possible across interior mountainous
areas today with scattered thunderstorms possible across northern
Trinity County.

Interior valley temperatures will likely reach the upper 90s and low
100s by mid afternoon as well.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Isolated thunderstorms are possible over the Trinity horn on Monday
and Tuesday afternoons and evenings.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.

CAZ101-103-104-106-109-110-112-113-262200-
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Southern Humboldt Interior-Mendocino Coast-
Northwestern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
257 PM PDT Sun Jun 25 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.

In the hours before

Special weather statement, Jun 25, 4:37 PM PDT, 0 minutes before
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Nearby

Special Weather Statements in California, 2017Every special weather statement 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.