Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Eureka California
440 am PDT Wednesday Jul 1 2015
Synopsis...very hot conditions will continue across the interior
valleys through Thursday. Seasonal conditions will persist along
the coastal plains. Monsoonal moisture will bring a chance of
thunderstorms to the mountains late in the week and over the
Discussion...upper level ridge continues to extend from Utah across
north California. The center of the 594-596 dam upper high will shift west-northwest
today and be centered over extreme north California and northwest Nevada before weakening
on Thursday night. As a result...inland high temperatures today are
expected to be near or slightly above the hot values from Tuesday.
As forecast temperatures have remained basically unchanged from
previous package...have maintained the heat advisory for our east
zones. Best chances of advisory conditions are this afternoon with
warm temperatures continuing into tonight. The heat advisory area
shrinks for Thursday...mainly remaining over a small part of the north
coast interior zones and portions of Trinity County. Although the
upper high will remain strong through most of the day Thursday...monsoonal
moisture will spread into the area from the S and southeast...with
increases in cloud cover...as well as isolated showers and
thunderstorms. This may prevent maximum temperatures from reaching
advisory levels...but uncertainty remains high and don't want to
lower advisory only to have to raise it again. Low clouds and
patchy nighttime and morning fog will continue affect coastal
areas...with improving conditions most afternoons.
The ridge will continue to gradually break down into the
weekend...to be replaced by a weak trough. An upper low is prognosticated
to develop well SW of north California late in the week...then gradually shift
NE closer to the coast. This will bring gradually cooler
temperatures for inland sections along with isolated to low end
scattered probability of precipitation for the interior. /Sec
Aviation...extensive stratus was covering the coast this morning.
Expect the stratus to meander near or at the coastline through the
day then press slightly into the coastal river valleys tonight.
Marine...cancelled the Gale Warning in the northern outer waters
and replaced it with a hazardous seas warning until 5pm this
afternoon. The thinking is that the coverage of gale force gusts has
not been sufficient to warrant a continuation of the warning. Nwps
and enp indicate seas remaining near 10 feet at 8 seconds through this
afternoon. The coverage will be about half of the zone...over the
western and northern portions of pzz470. Northerly winds over the
outer waters will continue to generate hazardous seas for small
craft through the week. Northerly winds will ease up over the
weekend with a corresponding decrease in seas. Broad low pressure
will develop over the area Sat and sun with southerly winds surging
northward along the entire coast.
California...heat advisory from 1 PM this afternoon to 1 am Thursday for caz076.
Heat advisory from 1 PM this afternoon to 1 am Friday
Northwest California coastal waters...
Small Craft Advisory until 9 am this morning for pzz450.
Hazardous seas warning until 5 PM this afternoon for pzz470.
Small Craft Advisory until 5 am Thursday for pzz475.
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