Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Eureka California
429 am PDT Wednesday may 27 2015
Synopsis...dry and warmer weather will prevail across the
interior through the week. Coastal areas will continue to see
night and morning low clouds with partial afternoon clearing.
Discussion...an upper low over eastern Washington and Idaho will
slowly track eastward today as an upper ridge near 130w builds
closer to the California coast. There will be much less
instability over the interior today. The nam12 continues to
indicate weak cape and instability over The Horn of Trinity and
yolla bollys this afternoon for the possiblity of isolated
showers. The soundings continue to show too much middle layer
stability for significant cumulus convection today. Nam12 and GFS
continue to show higher cape values and decreasing stability on
Thursday and Friday. Both models generate spotty precipitation over the
mountains. Once again conditions will be too stabe for thunderstorms. A
few showers certainly seem possible. Overall dry and warmer
weather conditions will continue to be the rule for most of the
area most of the time through Sat as a broad Flat Ridge holds over
the area. The stratus forecast will be based largely on
persistence. Warming aloft over the next few days may smash the
marine layer depth and allow faster clearing to the coastline in
the afternoon. However the flow will remain strongly onshore and
any clearing will be brief.
Both the GFS and European model (ecmwf) have been consistent on bringing an upper
trough toward the coast sun into Monday. Both models generate some
precipitation as well. Precipitation chances have been beefed up across the
board. Rain chances may need to be increased more if the models
remain consistent. It does not look like a rain out on sun or
Monday. Some showers will be possible...however the timing and
coverage are still very uncertain.
Aviation...morning pics from space showing another deep marine
layer thus not anticipating much clearing again today. Although
ceilings should lift into marginal VFR later this afternoon. Interior
valleys looking better in terms of a lack of morning clouds and
any clouds that do develop will likely dissipate by middle morning
leaving VFR for the remainder of the taf cycle.
Marine...northerly winds will continue through the week as a
ridge of high pressure remains stationed just offshore. Small
craft advisories were extended last night over the outer waters
mainly due to residual short period waves. Steep seas will persist
in response to the fresh winds. Otherwise a south, southwest wave
group will impact the waters as a low pressure system approaches
California and a northwest swell will diminish through the week.
Northwest California coastal waters...
Small Craft Advisory until 3 am PDT Thursday for pzz470-475.
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