Heat Advisory 4, NWS Eureka, CA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
425 AM PDT Sun Aug 27 2017

.SYNOPSIS...Hot conditions can be expected again throughout the
interior today, with another round of warm temperatures and sunny
skies along the coast as well. Temperatures will remain well above
normal across the interior through Tuesday, with modest cooling by
mid-week. More hot temperatures are expected this weekend.

&&

.DISCUSSION...Another few days of hot and dry conditions can be
expected throughout the region as high pressure aloft continues
unabated. Conditions today will likely be very similar to what
occurred yesterday, with interior temperatures likely to reach
near and slightly above 100 degrees in many areas. Along the
coast, mid-level temperatures continue to warm with the assistance
of developing southeast flow aloft, and the marine layer remains
very shallow. As a result, coastal locations can expect to see
another warm and cloudless day, and likely even a few degrees
warmer than what was seen yesterday. As a result, today may very
well end up being one of the warmest days of the calendar year in
some coastal cities. In fact, temperatures in downtown Eureka and
Arcata may very well reach into the low 70s, with some outer
neighborhoods like Cutten and Fieldbrook climbing to near 80
degrees. If this occurs, it will be the first time that
temperatures at the weather station on Woodley Island have reached
70 degrees since November 7 of last year...a streak of 289 days.

As for the smoke...generally light winds will persist again
today, with gradually increasing westerly onshore flow during the
day, and light offshore flow overnight. Prevailing winds aloft
have also turned to the south-southeast, which will likely begin
to carry some of the higher level smoke northward into Oregon.
However, folks will continue to see smoke in the Klamath and
Trinity River valleys, with some improvement from mid to late
afternoon as the inversion breaks and smoke is allowed to
disperse.

Temperatures will once again be well above normal tomorrow and
Tuesday throughout the interior, although a steadily deepening
marine layer will result in steadily cooling temperatures along
the coast. This deepening marine layer will also bring the return
of coastal stratus, likely arriving by tomorrow morning. by mid-
week, the upper level ride will weaken slightly and allow for a
brief period of modest cooling Wednesday and maybe Thursday...with
an emphasis on "modest." Even during this time period temperatures
will remain near to slightly above normal. Heat will return with a
vengeance toward the end of the week and weekend as an even
stronger ridge of high pressure builds off the coast and spreads
onshore. With current model projections as they are, much of
northern CA and Oregon can expect to see another several days of
well above normal temperatures Friday and beyond. /BRC

&&

.AVIATION...Clear skies were observed across much of the region
early Sunday morning, with patchy ground fog developing along the
Humboldt/Del Norte coast. Marine stratus appears unlikely at this
time due to a very shallow moist layer in the low-levels of the
atmosphere...and model guidance indicates these conditions will
persist through the next 24 hours. However, reduced ceilings and
visibility will possible over Del Norte county this morning due
to smoke spreading westward from inland wildfires. Conditions may
improve slightly during the afternoon as onshore winds develop.
Otherwise, VFR conditions are expected over interior Mendocino
county in the vicinity of KUKI.

&&

.MARINE...A period of weak north-northwesterlies and average seas is
forecast to persist through early next week. Thereafter, surface
high pressure will likely build over the northeastern Pacific during
Thursday, which will aid in strengthening northerly winds, with
occasional gale force gusts occurring over the outer waters. The
increase in wind speeds will yield steep seas from 7-11 feet over
the outer coastal waters. These conditions are forecast to subside
by Saturday afternoon.

&&

.FIRE WEATHER...Hot and very dry conditions are expected once
again today throughout the region. As expected, overnight
humidity recoveries have been poor from the mid-slopes upward
within the thermal belt, and by mid afternoon many areas will once
again plummet into the low teens and single digits. Temperatures
will also be well above normal, likely reaching near to slightly
above 100 degrees. Winds will gradually shift from the east and
southeast to westerly as onshore flow develops late morning into
the afternoon, with an added upvalley contribution near peak
heating. While these winds will be mostly light, some erratic
gustiness is expected, particularly by mid afternoon.

Meanwhile, a very shallow marine layer will result in
exceptionally warm and dry conditions very near the immediate
coast. While low lying coastal areas will not be as hot as the
interior, many areas will see the warmest temperatures of the
year with very low humidity relative to normal.

Temperatures will remain above normal through Tuesday, with
continued low humidity. However, the marine layer will gradually
deepen, providing some relief for coastal areas. After some modest
cooling Wednesday and Thursday, even more hot temperatures are
expected Friday and beyond.

As for smoke dispersion, continued light low level winds will
likely result in similar local smoke conditions to what was seen
yesterday. However, increasing southerly winds aloft will likely
begin to carry the higher level smoke off to the north. /BRC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...Red Flag Warning until 5 PM PDT this afternoon for CAZ203-204.

NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&

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Hazardous Weather Outlook
National Weather Service Eureka CA
336 AM PDT Sun Aug 27 2017

CAZ101-103-109-281045-
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
336 AM PDT Sun Aug 27 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...Today 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.

CAZ104-106-108-110>113-281045-
Southwestern Humboldt-Southern Humboldt Interior-Southern Trinity-
Northwestern Mendocino Interior-Northeastern Mendocino Interior-
Southwestern Mendocino Interior-Southeastern Mendocino Interior-
336 AM PDT Sun Aug 27 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

Above normal temperatures can be expected today, likely reaching or
exceeding 100 degrees. A moderate risk of heat related illness is
expected.

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

Above normal temperatures will continue through Tuesday, resulting
in a low to moderate risk for heat related illness.

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

CAZ102-105-281045-
Del Norte Interior-Northern Humboldt Interior-
336 AM PDT Sun Aug 27 2017

...RED FLAG WARNING IN EFFECT UNTIL 5 PM PDT THIS AFTERNOON...

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

A Red Flag Warning is currently in effect for extremely low
humidities.

Above normal temperatures can be expected today, likely reaching
near 100 degrees. A low to moderate risk of heat related illness is
expected.

Smoke may also periodically result in degraded air quality.

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

Above normal temperatures will continue through Tuesday, resulting
in a low to moderate risk for heat related illness.

Smoke may also periodically result in degraded air quality.

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

CAZ107-281045-
Northern Trinity-
336 AM PDT Sun Aug 27 2017

This hazardous weather outlook is for northwest California.

.DAY ONE...Today and tonight.

Above normal temperatures can be expected today, likely reaching or
exceeding 100 degrees. A moderate risk of heat related illness is
expected.

Smoke from wild fires in Siskiyou county may also periodically
result in degraded air quality.

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

Above normal temperatures will continue through Tuesday, resulting
in a low to moderate risk for heat related illness.

Smoke from wild fires in Siskiyou county may also periodically
result in degraded air quality.

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