textproduct: Portland

SYNOPSIS

Temperatures cool off tonight after a hot spring day. The upper level pattern shifts east tonight and supporting cooler but still above average temperatures to the area through the week. Uncertainty increases late in the week with the ridge pattern possibly breaking down toward the weekend.

LONG TERM...Monday through Sunday

Temperatures are expected to moderate back into the 60s along the coast and in the higher terrain and 70s elsewhere on Monday and through much of the workweek as the ridge axis shifts inland. Highs will still run 5-10 degrees above normal for this time of year. Winds turn southerly with the ridge shifting eastward which will help support chances for marine stratus to develop along the coast. Ensembles show a strong consensus for dry conditions through the workweek for much of the area. However, there is a low (10-20%) chance for a pop-up shower or thunderstorm over the Lane and Linn county cascades both Monday and Tuesday afternoon. Could also see some light drizzle along the coast if the marine stratus is thick enough.

Cluster analysis favors the ridge flattening out toward the end of the week as a shortwave rides over the ridge. This could lead to a pattern shift back to cooler temperatures and low chances for light rain. The current forecast maintains temperatures slightly above normal next weekend, however, there is a decent amount of uncertainty in the forecast. -19

AVIATION

VFR conditions prevail at all NW OR and SW WA terminals on Sunday under high pressure. Winds along the coast expected to be northwest to westerly less than 10 kts. Chances for showers and thunderstorms continue over the western slopes of the central Oregon Cascades, but confidence in terminal impacts remains very low. The more likely scenario is convective outflow debris in the form of high cloud cover may develop in the late afternoon to early evening.

After 03-06z Mon, a wind reversal will see low-level flow turn southerly across the region, spreading from south to north through 12z Mon. At coastal terminals, a renewed push of marine stratus will most likely see a return to MVFR/IFR cigs, returning by 03-06z Mon at KONP and 09-12z Mon at KAST. This marine push looks strong enough reach inland to KEUG and the southern Willamette Valley by 09-12z Mon with a 70-80% chance of MVFR conditions and 50-60% chance of IFR conditions. Additionally, there's a 30-40% chance MVFR cigs reach as far north as KSLE and a 15-20% chance they reach KPDX and surrounding terminals. Expect inland locations to improve to VFR by 18-21z Mon.

KPDX AND APPROACHES...VFR conditions expected throughout the period beneath largely clear skies. Northeasterly flow around 5-8 kt will turn northerly around 00z Mon, then ultimately southerly by 10-12z Mon. Convective debris in the form of high cloud cover may increase this afternoon and evening, but no terminal impacts are anticipated. There's a 15-20% chance of marine stratus with MVFR conditions impacting KPDX and surrounding terminals after 12-16z Mon. -03/36

MARINE

North winds continue this afternoon with occasional gusts up to 18-20 kts possible north of Cape Foulweather, calming this evening. A southerly wind reversal begins this evening south of Cape Foulweather, with the wind transition spreading from the southern waters to the northern waters overnight. A period of elevated south winds form along the inner waters late tonight through Monday morning with gusts up to 18-20 kts. South winds continue into Tuesday and will bring a resurgence of marine stratus tonight through Tuesday night which could result in overnight or early morning drizzle or light rain. Seas around 6-8 feet through Monday, falling to 4-5 feet on Tuesday. Northerly winds return towards the latter part of the week with persistent seas of 4-6 ft. -03

CLIMATE

Daily record high temperatures for Sunday, May 3

Location Forecast Record Year

Astoria 78 81 1992, 1944 Vancouver 90 84 1944 Portland Int'l 91 89 1992 Hillsboro 91 82 2017 McMinnville 86 87 1992 Salem 86 86 1992 Eugene 83 83 1944

PQR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory until 11 PM PDT this evening for ORZ108-109-111- 112.

WA...Heat Advisory until 11 PM PDT this evening for WAZ204>207.

PZ...None.