Area Forecast Discussion
Issued by NWS Eureka, CA
FXUS66 KEKA 271054
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
354 AM PDT TUE SEP 27 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...Overnight pics from space showing a growing layer
of stratus off the coast...even more than what the visual imagery
showed yesterday afternoon. So the return of marine influence
(clouds and fog) should be well intact as onshore flow gains
strength. This and 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. Nonetheless there still 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/JT
.AVIATION...Fog and low clouds have been producing LIFR conditions
at both KACV and KCEC through the night. Conditions should improve
some by this afternoon as the land mass heats up, however confidence
is not high the clearing will be complete or last long. Northerly
winds offshore will result in more low cloud and fog generation by
this evening. Conditions will deteriorate quickly and VSBYS and
ceilings may fall below minimums again this evening. VFR will
continue at KUKI through the period.
.MARINE...ASCAT pass Monday evening indicated north winds around
20-25 kt across the outer waters. Wind reports from the buoys were
not as strong. Combined seas will build to 10 ft today and remain
elevated through Wed night. SMALL CRAFT ADVISORIES for both winds
and combined seas are in effect for the outer waters. North winds
and seas will start to ease on Thu and then fall off even more on
Fri as a front approaches the offshore waters.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 AM PDT Thursday for PZZ470-475.
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