Marine Weather and Tide Forecast for Willapa, WA

SHORT TERM
Now through Wednesday Night...A stretch of cool and unsettled weather is underway across southwest Washington and northwest Oregon, thanks to a broad low pressure system moving through the region. Many areas are seeing off and on showers today, and there is a slight chance for isolated thunderstorms this afternoon and evening, especially inland.
While conditions of the atmosphere are not entirely favorable for frequent thunderstorms (long skinny CAPE), there is a 15-30% chance for enough cool air aloft and modest atmospheric instability to support a few lightning-producing cells. Any thunderstorms that do develop are expected to be brief and not particularly intense, but a few may produce very small hail (less than a quarter inch in size) and could create slick spots on roads or sidewalks for short periods.

Rainfall totals today will differ greatly over the area as showers have been stalling, weakening, and then redeveloping over nearby locations. In general, expect totals around 0.10 to 0.30 inches in the valleys and along the coast, with locally higher amounts up to 0.60 inches possible in the Cascades.

By Tuesday, showers will start to fade as the system shifts off to the southeast. A weak ridge of high pressure will begin to build in behind it, helping to dry things out slightly and bring more stability. A few lingering light showers could still pop up Tuesday, especially in the interior valleys and Cascades, but accumulations should be minimum - less than 0.05 inches in most lower elevation areas and up to 0.20 inches in the mountains.

Wednesday will mark a noticeable break in the wet pattern. With the ridge in place, expect drier conditions, a bit more sun, and a slight bump in temperatures.

LONG TERM
Thursday through Sunday...Another system is expected to swing through Thursday, bringing renewed chances for light precipitation across the region. However, temperatures should stay slightly above average for this time of year, especially inland. Forecast models suggest that as we head toward next week, high pressure may start to build over the eastern Pacific and push into the western US, favoring a shift toward drier and more stable conditions.

For now, expect coastal highs to stay in the 50s and inland highs to rise into the 60s through the latter part of the week and into the weekend.
~Hall

AVIATION
An upper level low over the region will continue to bring scattered showers and isolated thunderstorms to northwest OR and southwest WA through 00-03z Tuesday before convection diminishes after 03-06z Tuesday. Until then, any stronger shower or thunderstorm that does develop will have the potential to produce brief heavy downpours, small hail around the size of peas or smaller, and brief IFR to MVFR cigs and/or visibilities. Away from stronger showers and storms, conditions will generally remain VFR through 09-12z Tuesday. After 12z Tuesday, chances for MVFR cigs increase to 80-90% at the coast and 40-60% inland. Note thunderstorm probabilities are too low to justify a PROB30 group at any given TAF site.

PDX AND APPROACHES...Off and on rain showers will continue through 00-03z Tuesday before diminishing thereafter. There is also a 15-20% chance of thunderstorms until then. Any stronger shower or thunderstorm that moves over the terminal will have the potential to produce brief heavy downpours, small hail around the size of peas or smaller, and brief IFR to MVFR cigs and/or visibilities. Away from convection, conditions will generally remain VFR until approximately 09-12z Tuesday when MVFR cigs below 3000 ft will likely develop (40-60% chance). -TK

MARINE
Northwest winds will increase over the coastal waters this evening into tonight as low pressure moves inland. Expect gusts up to 20-25 kt over the outer waters and up to 15-20 kt over the inner waters. In addition, a northwesterly swell will increase to 8 to 10 ft at 10 seconds by Tuesday morning. Given the increasing seas and winds, have issued a Small Craft Advisory for the outer waters from this evening through Tuesday night and for the inner waters from Tuesday afternoon through Tuesday evening.
Have also issued a marginal Small Craft Advisory for the Columbia River Bar to cover a strong ebb current Tuesday morning and another ebb current Tuesday evening. Expect seas as high as 9-10 ft during both ebb currents.

Winds and seas gradually fall Wednesday through Thursday as high pressure builds in, bringing weaker northwest winds and seas below 6-8 ft. -TK



PQR WATCHES/WARNINGS/ADVISORIES

OR...None.
WA...None.
PZ...Small Craft Advisory from 3 AM to 11 PM PDT Tuesday for PZZ210.

Small Craft Advisory from 11 AM to 11 PM PDT Tuesday for PZZ251>253.

Small Craft Advisory until 5 AM PDT Wednesday for PZZ271>273.