Marine Weather and Tide Forecast for Copalis Beach, WA

SHORT TERM /TODAY THROUGH FRIDAY/
An upper level ridge will build into the Pacific Northwest today and persist over the region through Thursday, bringing warmer and and drier conditions to western Washington. With some moisture lingering in the low levels, satellite imagery this morning shows some areas of stratus developing along the North Coast and across portions of the interior. Expect stratus to persist through the early to mid morning hours, before scattering and making way for more sunshine by the early afternoon. Afternoon high temperatures today are expected to approach the upper 50s along the coast and the 60s for much of the interior.

Warm and dry conditions will continue into Thursday. While overall moisture in the low levels looks to decrease, a few spots of patchy fog will still be possible across portions of the interior by early Thursday morning. Expect any areas of fog to dissipate rather quickly once the sun comes up for clear skies to persist through the remainder of the day. Afternoon high temperatures will climb to roughly 10 to 15 degrees above normal, topping out in the upper 60s to low 70s along the coast and the 70s across the interior. A few spots along the Cascade foothills and valleys may even make it into the low 80s. The lowlands will be warm enough for widespread Minor (Yellow) HeatRisk.

The upper level ridge axis will then push further inland on Friday while an upper level trough approaches the coast. A weak frontal system will then bring the next chance of showers to the area, with rain likely approaching the coast by Friday afternoon and spreading inland late Friday into early Saturday. High temperatures will cool to near normal for areas along the coast on Friday as a result, with most spots topping out in the upper 50s. Southerly flow aloft will continue to promote warm temperatures for areas across the interior, however, where highs are still expected to climb into the upper 60s to low 70s. This will maintain Minor (Yellow) HeatRisk for lowland areas along the Sound.

LONG TERM /SATURDAY THROUGH TUESDAY/
The upper trough will split apart as it moves inland on Saturday. This will mainly bring light showers to the region, with most lowland locations only expected to pick up a few hundredths to around a tenth of an inch of rain. High temperatures on Saturday will cool into the 50s to low 60s area-wide. Showers then look to become more confined to higher terrain by late Saturday night into Sunday morning under split flow aloft.

There still remains some discrepancy in the weather pattern heading into early next week. Operational guidance continues to show another ridge nudging back into the region for warmer and drier conditions, while ensembles keep chances of showers in the forecast through the first part of the week. Have maintained chances of showers in the forecast for now, but will need to see how this trends in the coming days. 14

AVIATION
An upper level ridge will build into the region today with north to northwest flow aloft. Residual moisture will scatter out by afternoon with increasing low level northerly flow.
Areas of high end MVFR ceilings will lift to VFR by around 18Z with skies clearing this afternoon.

KSEA...Periods of high end MVFR ceilings this morning will lift and scatter out this afternoon. Surface winds light and variable early will shift northerly midday and rise to 7 to 10 knots this afternoon. 27

MARINE
Onshore flow will ease today as a surface ridge settles over the coastal waters. The ridge will weaken on Thursday in response to an approaching trough and associated frontal system over the offshore waters. A weakening front will move onshore into Western Washington late in the day on Friday with increasing onshore flow in its wake. This will likely lead to a period of headlines for winds across portions of the coastal waters and strait. Onshore flow will continue into Saturday before easing Sunday as a ridge rebuilds across the waters. 27

HYDROLOGY
No river flooding expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES
WA...None.
PZ...None.