textproduct: Portland

SYNOPSIS

Broad high pressure over the region will maintain generally dry conditions through the next several days. An upper level low offshore will bring chances for elevated thunderstorms over the Cascades today, however, some of which may track toward the Willamette Valley this afternoon and evening. A warming trend will peak on Sunday with daily record high temperatures in the forecast for some inland areas. Temperatures will cool but remain above normal into the next workweek.

LONG TERM...Monday through Friday

By the beginning of the workweek, ensemble guidance continues to favor moderating temperatures as the upper ridge axis moves inland. A southerly wind reversal will increase marine stratus coverage along the coast, with broader onshore flow cooling inland areas as well. There is general consensus in dry conditions across most of the region, however a minority of ensemble members depict very light rain or drizzle within the shallow marine layer, most likely in the overnight or early morning hours.

Late in the week, guidance favors a flattening of the upper ridge as shortwave impulses ride up and over its northern periphery. This pattern will favor temperatures cooling further toward seasonal norms, as well as supporting low (10-25%) chances for light rain across portions of the region. -36

AVIATION

Generally MVFR conditions expected to improve towards a VFR/MVFR mixture through 20Z Saturday along with an increasing probability for showers and thunderstorms for inland locations.

After 20Z Saturday, chances for showers increase along with a 15-35% chance for thunderstorms developing on the west side of the Cascade crest. Showers and thunderstorms are expected to track from the south/southeast to the northwest. Which does bring a threat of thunderstorms to most inland locations. At this time the chance for thunderstorms is 15-25%, with a start time for increased showers and thunderstorms starting around 00Z Sunday. Any showers or thunderstorms will tend to dissipate after 03Z Sunday.

North to northwesterly winds at 5-10 kt will continue through 03Z-06Z Sunday, when offshore northeasterly flow will begin to develop. As showers and thunderstorms move out of the area after 06Z Sunday, expect IFR/LIFR conditions to return to coast locations.

KPDX AND APPROACHES...Generally MVFR conditions expected to improve towards a VFR/MVFR mixture through 20Z Saturday. Slow clearing through the late afternoon will give way to an increasing showers and thunderstorm threat. Start time for increased showers and thunderstorms starting around 00Z Sunday. North to northwesterly winds at 5-10 kt will continue through 03Z-06Z Sunday, when offshore northeasterly flow will begin to develop. /42

MARINE

Northerly winds continue through the weekend, rising to diurnal peaks in the afternoon and easing overnight. A steady slackening of the surface pressure gradient will favor lighter winds through the weekend. A Small Craft Advisory remains in effect beyond 10 NM south of Cape Falcon through only 8 AM today before gusts fall below 20 kt. Seas of 5-6 ft this morning will slowly increase to 6-8 ft as a long-period northwest swell arrives through today. A further Small Craft Advisory has been hoisted for 3-9 AM Sunday within the Columbia River Bar as a strong ebb current yields steep seas of 7-8 ft.

A wind reversal on Monday will see southerly to southwesterly flow continue through Tuesday night, with increased low marine stratus and overnight drizzle or light rain across nearshore areas. More seasonable northerly flow redevelops in the latter half of the week with persistent seas of 4-6 ft. -36

CLIMATE

Daily record high temperatures for Sunday, May 3

Location Forecast Record Year

Astoria 75 81 1992, 1944 Vancouver 89 84 1944 Portland Int'l 91 89 1992 Hillsboro 89 82 2017 McMinnville 86 87 1992 Salem 86 86 1992 Eugene 83 83 1944

PQR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory from 8 AM to 11 PM PDT Sunday for ORZ108-109-111- 112.

WA...Heat Advisory from 8 AM to 11 PM PDT Sunday for WAZ204>207.

PZ...Small Craft Advisory from 3 AM to 9 AM PDT Sunday for PZZ210.