Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Eureka California
434 am PDT Wednesday may 6 2015
Synopsis...an upper trough will slowly sink south over
California this week however conditions will remain mostly dry
with only a few isolated showers over the interior mountains.
Temperatures should continue to be seasonal over the next few
Discussion...water vapor shows the upper level trough over the
Pacific northwest starting to sink south this morning. This is
keeping winds elevated across the area...mainly out of the
northeast and with the strongest winds on the ridges. For this
reason temperatures have been slow to fall this morning some
areas. Protected areas will likely be frosty this morning. Some
clouds persist around Humboldt Bay this morning...but the
offshore winds should clear them out quickly this morning. This
afternoon there is a chance for a few showers over eastern Trinity
County. For now kept the forecast dry...but this will need to be
watched. The lapse rates are fairly good...but only up through 400
mb or so. Also the moisture looks a bit limited.
Tonight temperatures will be fairly similar to this morning so
another frost advisory is possible. Winds may remain elevated
again like this morning...although temperatures aloft drop a bit
more as the upper level low sinks south.
Thursday models remain fairly consistent with dropping the low
down the state. Depending on the timing and strength this may
bring some thunderstorms to Trinity and eastern Mendocino
counties. For now have just showers in the forecast. The GFS has
better lapse rates aloft than the NAM so confidence is low on
thunder. Friday the low continues to move south so there is still
a possibility for showers and/or thunderstorms...however the
chance is lower so have left them out of the forecast.
Saturday the ridge of the high pressure looks to build over the
area briefly. This looks to be the warmest day of the week with
the ridge overhead. Skies are expected to be mainly clear. Later
in the weekend coastal stratus is likely as the ridge starts to
break down. Sunday through Tuesday model solutions start to
diverge as another cut off low starts to move down the coast. The
GFS remains stronger and farther south...while the European model (ecmwf) is slower
and weaker. The pattern looks to see continue seasonable
temperatures with some rain showers possible. Mkk
Aviation...VFR conditions and light winds to calm conditions will
continue at kuki through this morning. The winds will become
moderate and gusty during the afternoon at kuki with VFR conditions
continuing. VFR to MVFR conditions and light winds to calm
conditions will continue at kcec through this morning. The lower
conditions will be due to reduced ceilings and/or visibilities. The
winds will become moderate and gusty at kcec later this morning
through this evening with VFR conditions prevailing. MVFR conditions
and light winds to calm conditions will continue at kacv through the
early morning due to reduced ceilings. The winds will increase
becoming moderate and gusty later this morning through this evening
with VFR conditions occurring at kacv.
Marine...a strengthening offshore high pressure ridge interacting
with an inland low pressure system has increased the pressure
gradient across the waters. Subsequently the winds and steep seas
have increased. Small craft advisories will continue across the
northern outer waters and southern near shore waters through early
Friday morning due to the increasing winds and seas. A Gale Warning
is in effect across the southern outer waters through early Friday
morning. A Small Craft Advisory will be necessary across the
northern near shore waters this afternoon through early Friday
morning. Winds and seas will diminish Friday and Saturday in
advance of a weak cold front which will move through the region
frost advisory until 8 am PDT this morning for caz003-004-076.
Northwest California coastal waters...
Small Craft Advisory from 3 PM this afternoon to 3 am PDT Friday
Small Craft Advisory until 3 am PDT Friday for pzz470.
Small Craft Advisory until 3 am PDT early this morning
Gale Warning until 3 am PDT Friday for pzz475.
Small Craft Advisory until 3 am PDT Friday for pzz455.
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