textproduct: Portland

SYNOPSIS

Expect warm and sunny conditions for the 4th of July holiday. Temperatures warm up slightly tomorrow and Monday as high pressure builds, leading to localized Moderate HeatRisk. An upper-level trough moving into British Columbia Tuesday to Wednesday will cool temperatures a few degrees and bring slight chances for precipitation along the south Washington coast. Seasonable temperatures return Thursday to Friday with persistent onshore flow. Make sure to practice water safety when swimming in local rivers.

SHORT TERM...Today through Monday

Satellite imagery and surface observations as of early Saturday afternoon show sunny skies for most areas across northwest Oregon and southwest Washington as morning stratus has dissipated from daytime heating. There is still some lingering stratus along the coast, but that should gradually dissipate this afternoon and bring mostly sunny skies to the coast. Expect seasonable temperatures for the 4th of July holiday with afternoon highs peaking in the upper 70s to low 80s across interior valleys and 60s along the coast. We still have onshore flow, so can't rule out some marine clouds off the coast this afternoon and evening. By tonight, high resolution guidance suggests another return of widespread marine stratus along the coast.

Sunday to Monday, ensemble guidance continues to suggest high pressure building over the Pacific Northwest, resulting in warmer temperatures across the area. High temperatures across interior valleys are forecast a few degrees warmer tomorrow in the mid 80s, then peaking on Monday in the upper 80s. Chances for exceeding 90 degrees have decreased since yesterday - now only a 10-35% chance across the Willamette Valley, 40-50% chance across the Upper Hood River Valley, and less than 10% for the rest of the interior valleys. However, we'll still have some localized Moderate HeatRisk on Monday within the inner Portland Metro and parts of the Gorge and Upper Hood River Valley. This means this level of heat will affect those sensitive to heat, especially those without adequate cooling or hydration. Low temperatures in the 50s across the entire area should provide decent overnight relief from the heat.

It is important to remember that while temperatures will be warm this holiday weekend and next week, many local lakes and rivers remain very cold and can cause cold water shock. Also, rivers may still have swift currents in some areas, which can quickly sweep you away. Please practice water safety by wearing life jackets, visiting with a buddy, and always being aware of your surroundings. -10

LONG TERM...Tuesday through Friday

The majority of ensemble members continue to show an upper-level trough from the Gulf of Alaska moving down into British Columbia and an upper-level high in the southwest United States, resulting in zonal flow over the Pacific Northwest. Given the more northern track of the incoming trough, the majority of our area is expected to be dry. An exception would be the south Washington coast where this system favors a slight chance (15-25%) for light rain on Wednesday. Given how dry our air mass is and how weak this system would be as it passes through our area, forecast precipitation amounts are minimal (around 0.01" or less). Despite the lack of precipitation, onshore flow will increase mid-week and support temperatures cooling a few degrees closer to seasonal normals for early July. West-northwesterly winds are generally expected to be light for most areas during this time. However, will see locally breezier winds along the central Columbia River Gorge and Upper Hood River Valley, where there is a 25-45% chance for at least isolated wind gusts exceeding 40 mph Tuesday and Wednesday.

At the end of next week, most ensemble members show the aforementioned trough weakening as it moves eastward through British Columbia. At the same time, ensemble members are showing additional troughing moving down from the Gulf of Alaska into the northeast Pacific/British Columbia. There still remains uncertainty with the exact placement and magnitude of this additional troughing, thus uncertainty with any potential impacts at this time. If this pattern does pan out, this would support continued onshore flow with seasonable temperatures. -10/42

AVIATION

High pressure remains over the region keeping conditions warm and dry. Marine stratus has finally broken out and the coast is beginning to lift. Will continue to see improvement through the afternoon before clouds fill in once again overnight. Afternoon diurnally driven northerly winds expected today with gusts up to 20 kt along the coast, and sustained 10-14 kt within the Willamette Valley - especially near KEUG.

Overnight is where the challenge comes in and whether or not we will see MVFR CIGs redevelop. Some positives is that there is a weak shortwave moving in which will increase winds earlier and thus mixing aloft. However, some models continue to show areas of MVFR CIGs in the interior valleys, with high probabilities along the coast.

KPDX AND APPROACHES...VFR through the next 12 hours or so then marine stratus appears to move back in after 10Z Sun. Northerly winds increase over the afternoon after 20Z Sat, but will be strongest after 00Z Sun. Around a 70% chance of MVFR CIGs redeveloping after 14Z Sun with some models suggesting similar probability for IFR CIGs. However, due to winds remaining elevated and drier air remaining, getting these levels will be more difficult. Cannot rule it out completely though. Winds will begin to increase late in the forecast as a weak disturbance passes through. -27

MARINE

High pressure over the region result in increasing winds and building seas through Monday. Northerly winds will slowly increase through this afternoon and will result in gusts up to 20 kt by this evening. Winds will continue to strengthen with gusts up to 30 kt by Sunday. Seas will also build from 4 to 6 ft towards 6 to 8 ft by Sunday. High pressure will slowly become displaced towards the start of next week, thus easing overall conditions by Monday night/Tuesday which is expected to persist through the remainder of next week. -42

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory from 11 PM this evening to 11 PM PDT Sunday for PZZ251-271.

Small Craft Advisory from 8 PM this evening to 11 PM PDT Sunday for PZZ252-272.

Small Craft Advisory from 2 PM this afternoon to 11 PM PDT Sunday for PZZ253-273.