Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 262232
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
332 PM PDT MON SEP 26 2016
.SYNOPSIS...A gradual cooling trend is expected to begin on
Tuesday as an upper ridge drifts slowly east through the week.
Some light rain may develop late in the week or over the weekend.
.DISCUSSION...Northwest California is located on the western
periphery of an upper level ridge this afternoon. The thermal trough
has shifted back east allowing northwesterly winds to redevelop
along the coast. After an early jump in coastal temperatures this
morning, temperatures have fallen back to normal for this time of
year once the winds turned back out of the northwest with the sea
breeze. Meanwhile temperatures across the interior remain hot with
many areas in the upper 90s to near 100.
A gradual cooling trend is in store for the next few days as an
upper trough deepens off the Pacific Northwest coast. 1000-500 mb
thickness values will descend from near 579 dam to 550 dam on
Friday. By Friday, high temperatures across the interior will
range from the 70s in the valleys to 50s in the mountains while
coastal areas stay in the 60s throughout the week.
The upper trough will bring increasing moisture to the region Friday
into the weekend. A chance for some rain showers over the northern
half of the forecast area will begin Friday and continue through
Saturday as the trough moves inland. Secondary shortwaves behind
the trough axis will then dive southeast toward the Pacific
Northwest and Northwest California Sunday through early next week.
There remains very high uncertainty as to the trajectory and
strength of each of these shortwaves with poor model run-to-run
consistency. Still, there looks like a decent shot of at least
some rain in the northern half of the area and the potential for
rain to fall across all of Northwest California at some point
Sunday into early next week. /RPA
.AVIATION...VFR conditions and light to moderate winds will
continue at KCEC and KACV through this evening. VFR to MVFR
conditions and light winds to calm conditions will prevail at KCEC
and KACV late this evening through early Tuesday morning. The
lower conditions will be due to reduced ceilings and/or
visibilities due to stratus and/or patchy fog. VFR conditions and
light winds to calm conditions will continue at KUKI the next few
.MARINE...An offshore high pressure system will strengthen Tuesday
and interact with an inland thermal low pressure trough. The
offshore high pressure system combined with the inland thermal low
pressure trough will increase the pressure gradient across the
waters and the winds and seas will increase primarily across the
outer waters Tuesday and Wednesday. Small craft advisories will be
in effect across the outer waters Tuesday through Thursday
morning. The winds and seas will diminish Thursday and Friday in
the wake of a weak cold front which will relax the pressure
gradient across the waters.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory from 11 PM this evening to 2 AM PDT
Thursday for PZZ470.
Small Craft Advisory from 4 PM Tuesday to 2 AM PDT
Thursday for PZZ475.
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