Special Weather Statement, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
246 PM PDT Fri Aug 9 2019

.SYNOPSIS...Cooler than normal inland temperatures will continue
through Saturday. Scattered thunderstorms, some potentially
strong, will be possible across primarily Trinity County Friday
afternoon and evening. Additional isolated showers and
thunderstorms will be possible in other areas overnight Friday
through Saturday. A warming and drying trend is expected next
week.

&&

.DISCUSSION...An anomalously deep upper low is currently centered
over the E Pacific near 40.5N/130.1W. This low is presently
moving ESE toward NW CA. The low is expected to reach the NW CA
coast Saturday morning before turning to the NE and filling
Saturday afternoon.

The marine layer has mostly broken up today. Mid and high
cloudiness covered portions of the area this morning, but most of
this cloudiness has shifted N of the area. Cumulus clouds have
been developing across mostly Trinity County over the past few
hours. A small thunderstorm recently developed over the tip of the
Trinity Horn and produced a cloud-to-ground lightning strike.

Thunderstorm chances across portions of NW California will
increase for the remainder of the afternoon as the low approaches
and upper forcing increases. The greatest chances of storms will
be across interior mountain ranges, but a few showers and
thunderstorms will also be possible across Humboldt and Del Norte
counties as the center of the low moves inland into early
Saturday.

Some storms may be strong over N Trinity County with gusty winds
near 40 mph and small hail possible. Stronger storms will be found
a bit farther to the N. Thunderstorms will be moving N at around
30 mph this afternoon, but storm motions will be slowing down
considerably overnight at the upper low moves nearly overhead and
winds throughout the atmospheric column drop off.

Rainfall totals during this event may exceed a tenth of an inch
over the N with locally higher amounts beneath slower moving
thunderstorms.

Rain chances will come to an end Saturday night with dry
conditions forecast into the middle of next week. Temperatures
over the interior will return to near to slightly above normal as
well. /SEC

&&

.AVIATION...Approaching upper level low is leading to VFR conditions
area wide this afternoon. A thunderstorm and a few showers have been
observed across primarily Trinity County this afternoon. The threat
for thunderstorms across Trinity County will continue through this
evening with the main threats being gusty winds, small hail, and
frequent lightning. The threat for primarily showers (albeit a few
thunderstorms will remain possible through early tomorrow morning)
will expand area wide late tonight and persist through early
tomorrow morning. These showers will lead to brief drops in ceilings
and visibilities into the MVFR range as well as the potential for
some gusty and erratic winds. /WCI

&&

.MARINE...A weakening surface pressure gradient in response to the
approaching upper low will yield light winds and generally calm seas
across the coastal waters through Sunday morning. Flat short period
seas will subsequently leave a small long period southerly swell as
the primary wave group in the short term portion of the forecast.
Thunderstorms will be possible over the waters this afternoon into
Saturday morning as the low moves overhead. These storms will be
capable of producing locally gusty winds and frequent lightning.

Northerly winds and steeper seas will start to trend upward again on
Sunday in the wake of the low, with the next round of Small Craft
Advisories likely to be needed across at least the outer zones by
early to mid next week. Moderate to locally strong northerly breezes
will then remain in the forecast through much of next week.
/CB&WCI

&&

.FIRE WEATHER...Multiple rounds of thunderstorms will be possible
across NW California between this afternoon Saturday afternoon.
The best chances for stronger storms capable of producing numerous
lightning strikes are likely to occur late this afternoon and
evening, and primarily across portions of Trinity County and
farther to the north across Siskiyou County and points north.
While the stronger storms are likely to produce wetting rain
within their cores, they may also produce significant lightning,
and will likely move quickly to the north. Given the locally dry
fuels present, numerous lightning-caused fire starts will be
possible in areas that avoid significant rain from thunderstorm
cores. A Red Flag Warning continues for fire weather zones 283
(mainly N half) and 204 (mainly in Siskiyou County) through
Saturday morning.

After the initial round of scattered thunderstorms this afternoon
and evening, additional showers and isolated thunderstorms will
continue to be possible tonight through Saturday afternoon. These
later storms are expected to move more slowly and be wetter,
cutting down on the threat of lightning starts. /SEC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...

CA...Red Flag Warning until 8 AM Saturday for CAZ204-283.
NORTHWEST CALIFORNIA COASTAL WATERS...None.

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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png

Hazardous Weather Outlook
National Weather Service Eureka CA
337 AM PDT Fri Aug 9 2019

CAZ101-103-104-109-101045-
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Mendocino Coast-
337 AM PDT Fri Aug 9 2019

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

There is a slight chance of thunderstorms this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

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

CAZ110-112-113-101045-
Northwestern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
337 AM PDT Fri Aug 9 2019

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

There is a slight chance of thunderstorms this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

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

CAZ102-101045-
Del Norte Interior-
337 AM PDT Fri Aug 9 2019

...RED FLAG WARNING IN EFFECT FROM 1 PM THIS AFTERNOON TO 8 AM PDT
SATURDAY...

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

A Red Flag Warning is in effect after 1 pm this afternoon. Isolated
to scattered showers and thunderstorms will develop this afternoon
and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

A Red Flag Warning is currently in effect through 8 am Saturday.
Isolated thunderstorms will be possible on Saturday.

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

CAZ106-111-101045-
Southern Humboldt Interior-Northeastern Mendocino Interior-
337 AM PDT Fri Aug 9 2019

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

There is a slight chance of thunderstorms this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

There is a slight chance of thunderstorms on Saturday.

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

CAZ105-107-108-101045-
Northern Humboldt Interior-Northern Trinity-Southern Trinity-
337 AM PDT Fri Aug 9 2019

...RED FLAG WARNING IN EFFECT FROM 1 PM THIS AFTERNOON TO 8 AM PDT
SATURDAY...

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

A Red Flag Warning is in effect after 1 pm this afternoon. Scattered
showers and thunderstorms will develop this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

A Red Flag Warning is currently in effect through 8 am Saturday.
Isolated thunderstorms will be possible on Saturday.

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

Special Weather Statement
National Weather Service Eureka CA
647 PM PDT Fri Aug 9 2019

CAZ107-108-100200-
Southern Trinity CA-Northern Trinity CA-
647 PM PDT Fri Aug 9 2019

...SPECIAL WEATHER STATEMENT...

At 647 PM PDT, Doppler radar was tracking a strong thunderstorm over
Junction City, or near Weaverville, moving north at 20 mph.

Pea size hail will be possible with this storm.

Locations impacted include...
Weaverville, Hayfork, Junction City and Helena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 4061 12300 4062 12313 4092 12314 4089 12284
TIME...MOT...LOC 0147Z 190DEG 19KT 4069 12305

Special Weather Statement
National Weather Service Eureka CA
858 PM PDT Fri Aug 9 2019

CAZ107-100430-
Northern Trinity CA-
858 PM PDT Fri Aug 9 2019

...SPECIAL WEATHER STATEMENT...

At 857 PM PDT, Doppler radar was tracking a strong thunderstorm near
Douglas City, or 7 miles south of Weaverville, moving north at 20
mph.

Half inch hail will be possible with this storm.

Locations impacted include...
Weaverville, Douglas City and Lewiston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4057 12282 4056 12294 4086 12312 4090 12277
TIME...MOT...LOC 0357Z 170DEG 18KT 4062 12290

Special Weather Statement
National Weather Service Eureka CA
904 PM PDT Fri Aug 9 2019

CAZ107-100445-
Northern Trinity CA-
904 PM PDT Fri Aug 9 2019

...SPECIAL WEATHER STATEMENT...

At 903 PM PDT, Doppler radar was tracking a strong thunderstorm over
Douglas City, or near Weaverville, moving north at 20 mph.

Half inch hail will be possible with this storm.

Locations impacted include...
Weaverville, Douglas City and Lewiston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4057 12282 4056 12294 4086 12312 4090 12277
TIME...MOT...LOC 0403Z 170DEG 18KT 4065 12290