Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 301243 CCA
AREA FORECAST DISCUSSION...CORRECTED
National Weather Service Eureka CA
543 AM PDT Thu Mar 30 2017
.SYNOPSIS...High pressure will build toward the coast today
resulting in dry weather conditions that will last through
.DISCUSSION...Robust northwesterly flow has developed in the
wake of vigorous mid level shortwave trough progressing eastward
over the Sierra-Cascade range as of 5am. Moist northwesterly
onshore flow in the lowest 5kft of the atmosphere may continue to
produce spotty light showers til mid morning primarily out toward
the coast and over the coastal mountains. Otherwise it shaping up
to be dry (no rain) today. The brisk northwesterly winds should
lay down by daybreak, then ramp up again this afternoon as the
land mass heats up and surface high pressure builds toward the
coast. The ARW has high boundary layer humidities advecting
onto the north coast through the day and high based low cloud
cover will probably reform as the winds increase and a high but
weak inversion develops. Winds will become northeasterly to
easterly late tonight, scouring or pushing away the low clouds.
Friday should be sunny and pleasant, except for the afternoon
sea breezes which may get locally strong for a few hours right at
the ocean-land interface.
We hoisted another frost advisory for interior Mendocino county
where late night/early morning temperatures are expected to dip
into the mid 30s. Winds will also be a factor that will keep
temperatures from rapidly falling into the mid 30s this evening.
Only a few hours of early morning readings in the mid 30s are
expected in the coldest valleys. The air mass will warm up
Friday night and another frost advisory probably will not be
necessary, though a few sites may still be close to 35F early
Saturday morning. Afternoon temperatures will warm up nicely on
Saturday in the interior. Readings should top out in the mid 70s
to lower 80s. The nice weather should continue on Sunday. There
is one fly-in-the-ointment though. The ECMWF and GFS continue to
depict a mid level shortwave trough moving into the Pacific
Northwest and then clipping northeast Trinity county with some
shower potential. The models have been inconsistent and all over
the place. Confidence is low there will be any showers. The
latest ECMWF still shows a slight possibility for Sunday. Other
than that one minor ripple on Sunday, dry and fine weather
conditions will hold into the early portion of next week as upper
level ridging remains firmly entrenched over the region. The rain
we had coming in for mid week is not looking very promising and
the chances have been cut-back. It may be another fine and warm
day for the interior on Wed as well. It does look like coastal
stratus will be making a come back early to mid next week. The
northerly flow should eventually die down and become southerly.
A front is expected to bring some rain late in the forecast
period, as late as Thu night. Confidence in the models that far
out, especially during Spring, is not high. See no reason to
get bullish and overly confident with rain chances this early in
Beach hazard and surf...There is a slight concern for sneaker
waves on Saturday as a long period westerly swell around 20
seconds hits 4 to 6 feet by Saturday evening. The greatest threat
appears to be Saturday evening. The one mitigating factor will be
shorter period wave energy from both wind waves and a mid period
west swell around 13 seconds. The swell will continue to build on
Sunday resulting in breakers possibly reaching 19 feet. For now
we have highlighted the threat in our hazardous weather outlook.
A beach hazard advisory may be necessary.
.AVIATION...VFR to MVFR conditions and moderate to moderate
and gusty winds will continue at KCEC and KACV through this
morning. The lower conditions will be due to reduced ceilings
and/or visibilities. VFR conditions and moderate and gusty winds
will prevail at KCEC and KACV this afternoon with light winds and
VFR conditions occurring overnight tonight. VFR to MVFR conditions
will continue at KUKI early this morning with light winds to calm
conditions occurring. VFR conditions and moderate and gusty winds
will occur at KUKI this afternoon and evening.
.MARINE...A weak cold front moved across the waters early this
morning. Moderate and gusty northerly winds increased behind the
frontal boundary this morning. A high pressure ridge will build
across the region today in the wake of the front. Small craft
advisories will continue in effect across the outer waters through
Friday afternoon. Small craft advisories will continue across the
near shore waters through early this morning. Another weak cold
front will move across the waters late Saturday and early Sunday.
Small craft advisories are likely across the waters this weekend
through Monday due to elevated winds and/or seas.
CA...Frost Advisory from 3 AM to 8 AM PDT Friday for CAZ110>113.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 9 AM PDT this morning for PZZ450-455.
Small Craft Advisory until 3 PM PDT Friday for PZZ470-475.
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