Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 282234
Area Forecast Discussion
National Weather Service Eureka CA
334 PM PDT SAT MAY 28 2016
A ridge of high pressure will build across our region early
next week. Dry conditions will prevail with temperatures
gradually warming over the next few days, especially for interior
locations.The weather pattern could become more interesting by
(Tonight and Sunday)
The weather looks like it`ll cooperate with your plans for any outdoor
activities this Memorial Day weekend. Northwestern California
remains "sandwiched" between the northern branch of the jet
stream, located near the Canadian border, and a shortwave
trough crossing SOCAL. With no real disturbance in the flow
affecting our area, mainly clear skies will persist with winds
gradually diminishing this evening, and lighter winds expected
compared to the past few days. Near to slightly above seasonal
values are expected during this time.
(Sunday evening through next Saturday)
The numerical models remain in good agreement through the middle of
next week. An upper-level ridge of high pressure will build across
the region, with the center of this high passing over northern
portions of the state in the Memorial Day/Tuesday time frame.
Heights will continue to rise, peaking in the 582 dkm (GFS) to
584 dkm (ECMWF) range during the day Tuesday. With the center of
the high passing overhead/nearby, winds will be light with dry
weather persisting, perfect for any outdoor plans that you may
Thereafter, model disagreement increases substantially. One of the
biggest discrepancies lies between the GFS/ECMWF models with regard
to the mid/upper-level patterns. The GFS wants to bring a shortwave
(and associated jet stream) into our area on Wednesday, displacing
the ridge axis farther east. Conversely the European model (ECMWF)
deflects more of this energy to our north, allowing the ridge axis to
remain closer to our neck of the woods, providing more influence
on our weather. Given the pattern in place preceding the mid-week
system, a slower displacement/more dominant ridge seems the best
way to go at this point, as models typically break down high-
amplitude ridges too fast.
The real question of interest is what will happen next weekend.
Here, model discontinuity really increases, with the GFS portraying
a less amplified pattern. That model shows a trough positioned to
our north off the northern Oregon/Washington coast, a mid-level
low near San Diego around 582 dkm, and not much change in these
mid- level heights from that low to our area. It then takes this
low due east along the northern Mexico/Desert Southwest border,
allowing the trough to dip south into the state. Meanwhile, the
European model has a much more amplified forecast, as it develops
an Omega blocking pattern with a 594+ dkm ridge centered over
eastern Nevada, and a stronger area of low pressure aloft (574 dkm
by Monday morning) heading towards San Francisco. The latter
solution would bring increasing moisture to the forecast area with
a good chance of shower and thunderstorm development, especially
across interior locations. Granted this is several days out,
but...it`s something to keep an eye on. /PD
.AVIATION....High pressure continues to bring clear skies across the
area this afternoon. This is combining with the thermal low over the
central valley and bringing gusty northwest winds to the coast and
near coastal areas. Gusts around 30 kt have been reported at
Crescent City. These winds are expected to persist through this
evening. Tonight offshore flow looks weaker than last night so a few
clouds are possible with the best chances around Humboldt Bay and up
the Eel river valley. Sunday clouds are expected to clear by mid to
late morning and another sunny day is expected. Winds will be gusty
once again, but will be lighter than today.
.MARINE...Strong high pressure over the northeastern Pacific and a
thermal low over the central valley of California is bringing gusty
northerly winds and steep short period waves to the waters this
afternoon. Models still indicate borderline gale force winds in the
southern outer waters through this evening. Later tonight winds look
to diminish a bit more so will not extend the gale warning. Sunday
winds and waves will be slightly weaker as a weak trough moves by to
Winds will decrease and steep waves will diminish early next week as
the ridge offshore breaks down and allows the gradient to relax.
Winds and seas are expected to be more subdued overall by mid to
late next week, however, uncertainty in the track of an approaching
weak low pressure system is resulting in below average confidence in
both wind speed and direction.
Meanwhile, model guidance continues to hint at a long period south
swell moving through the waters Wednesday. This will bring larger
sets of wave activity to south facing beaches and anchorages with
only minor impacts expected. MKK/KML
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 3 AM PDT Monday FOR PZZ450.
Small Craft Advisory until 3 AM PDT Tuesday FOR PZZ470.
Small Craft Advisory until 3 AM PDT Monday FOR PZZ455.
Gale Warning until 9 PM PDT this evening FOR PZZ475.
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