Special Weather Statement, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
255 PM PDT Mon Jun 12 2023

.SYNOPSIS...Isolated to scattered showers and slow-moving
thunderstorms will continue to develop across the interior this
afternoon. More isolated storms are possible Tuesday afternoon, but
drier weather is expected for the remainder of the week. Slightly
warmer temperatures are expected across the interior through the end
of the work week, with cooler temperatures expected late in the
weekend and early next week.

&&

.DISCUSSION...An upper low over the Great Basin will gradually fill
as it drifts ENE. Monsoonal moisture from this feature will continue
to decrease, but a weak, elongated trough will persist over S CA
through the rest of the week. N of the trough, a weak ridge will set
up from the E Pacific over N CA, which will bring a respite from
interior afternoon thunder by mid-week.

The marine layer has gradually deepened from the S today with several
coastal eddies bringing S flow along the immediate coast. A few
showers and storms have already developed over portions of Trinity
County this afternoon, and this will likely continue into the early
evening hours. Storm motion has continued to be to the SW, but models
indicate motion will gradually slow into the evening hours, with
locally heavy rainfall still possible beneath stronger or more
persistent storms.

Instability will rapidly wanes and precipitable water levels will begin
to drop Tuesday as moisture is shunted SE of the region. Recent
guidance has delayed this drying, giving us the possibility of a few
more storms Tuesday afternoon. However, this will likely be
relegated to only the highest elevations of the Yolla Bollies and
Trinity Alps. The mid levels of the atmosphere will then
significantly dry out Wednesday and Thursday with weak ridging aloft,
stifling interior shower development.

Temperatures will gradually increase across the interior over the
next several days, with daytime highs 5-10 degrees above normal
across the interior and nighttime lows about 5 degrees above normal.
Cluster ensemble guidance is nearly unanimously indicating the ridge
aloft breaking down sometime during the weekend, with a large trough
then dropping over the West Coast by early next week. Several of the
global models drop some anomalous weak storm systems into the Pacific
NW during this period, with the potential of some light rainfall
entering the extreme N portion of our area. /TDJ&SEC

&&

.AVIATION...The Bodega Bay profiler continues to show the marine
layer maintaining its deepened state, and even deepening further.
Visible satellite reversal several southerly return flow eddies just
offshore along the coast. Ceilings have lifted to IFR, but is
remaining embedded over the coast despite small patches of clearing
within the eddies. Not much change to the pattern through the 18Z
TAFs, with a return to LIFR CIGs, and TEMPO lower VIS into Tuesday
morning. The deep marine layer is once again expected to spill over
into the Ukiah Valley early this morning, with a IFR to possible LIFR
ceiling lingering at KUKI through the first half of the morning.

&&

.MARINE...Stronger northerly winds have pulled farther offshore
today while the lingering short period seas are subsiding. There will
only be a short break in advisory level conditions before the
northerlies increase again Tuesday morning. Gale force sustained
winds will occur in the northern outers Tuesday afternoon, followed
by expansion of gale winds and gusts into portions of the surrounding
waters by late Tuesday night. Winds will slowly begin weakening late
Thursday and Friday.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 4 PM this afternoon for PZZ470-475.
     Gale Watch from Tuesday afternoon through Thursday afternoon
      for PZZ470.

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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
244 AM PDT Mon Jun 12 2023

CAZ101>115-130945-
Coastal Del Norte-Del Norte Interior-Northern Humboldt Coast-
Southwestern Humboldt-Northern Humboldt Interior-
Southern Humboldt Interior-Northern Trinity-Southern Trinity-
Mendocino Coast-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
244 AM PDT Mon Jun 12 2023

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

Isolated to scattered showers and slow- moving mainly wet
thunderstorms are forecast to occur across much of the interior this
afternoon.

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

Isolated to scattered showers and slow- moving mainly wet
thunderstorms are forecast to occur across the highest elevations of
the Yolla Bollies and Trinity Alps Tuesday afternoon.

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

Special Weather Statement
National Weather Service Eureka CA
305 PM PDT Mon Jun 12 2023

CAZ107-122230-
Northern Trinity CA-
305 PM PDT Mon Jun 12 2023

...A strong thunderstorm will impact portions of central Trinity
County through 330 PM PDT...

At 305 PM PDT, Doppler radar was tracking a strong thunderstorm near
Helena, or 10 miles northwest of Weaverville, moving south at 5 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Helena.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4092 12313 4092 12302 4073 12300 4077 12322
TIME...MOT...LOC 2205Z 019DEG 5KT 4087 12310

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

ZVS

Special Weather Statement
National Weather Service Eureka CA
317 PM PDT Mon Jun 12 2023

CAZ107-108-122245-
Southern Trinity CA-Northern Trinity CA-
317 PM PDT Mon Jun 12 2023

...A strong thunderstorm will impact portions of central Trinity
County through 345 PM PDT...

At 316 PM PDT, Doppler radar was tracking a strong thunderstorm near
Hayfork and highway 3, moving south at 5 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hayfork and Junction City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4076 12315 4074 12301 4049 12306 4053 12328
TIME...MOT...LOC 2216Z 019DEG 5KT 4062 12310

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

ZVS

Special Weather Statement
National Weather Service Eureka CA
345 PM PDT Mon Jun 12 2023

CAZ107-108-122315-
Southern Trinity CA-Northern Trinity CA-
345 PM PDT Mon Jun 12 2023

...A strong thunderstorm will impact portions of southwestern Trinity
County through 415 PM PDT...

At 345 PM PDT, Doppler radar was tracking a strong thunderstorm over
Hayfork and highway 3, moving south at 5 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hayfork and Peanut.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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 4066 12325 4065 12303 4044 12305 4048 12335
TIME...MOT...LOC 2245Z 019DEG 5KT 4059 12315

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

ZVS