textproduct: Eureka

SYNOPSIS

Dry weather expected through Thursday. Rainshowers with interior thunderstorm chances increase Friday through Sunday.

DISCUSSION

Low pressure off the coast of southern California continues to cause subjectively "pleasant" weather. Windy afternoons after morning stratus is forecasted for coastal areas with interior areas to have continued slightly breezy, variable winds with valley high temperatures ranging from 70-80F through the rest of today and again Thursday. This weather pattern is expected to change come Friday however.

As the low pressure off SoCal begins to move eastward, an upper level trof will dip down into the PacNW. This trof will advect moisture into the area. PWAT values remain ample for rainshowers, with values between 0.7-1.0". In addition to moisture, high resolution model data is showing CAPE developing over the interior for Friday afternoon through Sunday. CAPE values of 250J/kg up to 1000J/kg are possible. The T-Storm possibility looks more likely for Friday and Saturday with NBM showing around a 10-15% probability of lightning developing over the northern interior areas each afternoon. Forecast confidence for Sunday will be available with new model runs. For areas that are not likely to get thunderstorms, a chance of wetting rain (>0.10") is possible (20-30%) to fall each afternoon. These rainshowers chances continue into next week. Each morning, valley fog/stratus is also possible as increased moisture enters the area. @DS

AVIATION

Skies have cleared across the entire region with VFR prevailing. Northerly winds will be gusty along the coast this afternoon. As temperatures cool overnight, cloud cover will likely once again redevelop over the coastal waters and expand into the near coast river valleys. MVFR to possible IFR ceilings will be possible at the coastal terminals overnight into Thursday morning. Gusty north winds over the waters will mix out the clouds through the day with a return to VFR and gusts in excess of 20 kt by the afternoon for the coastal terminals. Inland winds will remain light with VFR primarily through the forecast period. /RPA

MARINE

Northerly winds have increased over the coastal waters and seas spiked briefly at the buoys to around 8 to 9 feet. Seas have since subsided slightly, but are likely still elevated over the outer water zones. Thus, with gusty northerlies solidly in small craft criteria to near gale today through Saturday morning, seas are expected to continue to build and be very steep in the outer water zones. Considering only brief periods of gale are expected over that time, the gale watch has been cancelled and a hazardous seas warning has been issued in its place, starting immediately this afternoon. Seas will be a little less steep near the coast, only exceeding small craft criteria, resulting in only the need for a small craft advisories for those waters. To simplify the forecast, with the hazardous seas warning issued into the day Saturday, the small crafts for the inner water zones were also extended to Saturday as well despite that being a little beyond our typical policy.

Winds and seas will subside significantly over the weekend as an upper trough dives down toward the region, possibly resulting in a cut-off low spinning over the area for a few days. This will likely result in a weak pressure gradient and variable wind directions into early next week. /RPA

EKA WATCHES/WARNINGS/ADVISORIES

CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 9 AM PDT Saturday for PZZ450-455.

Hazardous Seas Warning until 9 AM PDT Saturday for PZZ470- 475.