textproduct: Portland

SYNOPSIS

Expect a break between weather systems today as weak high pressure quickly passes overhead. Steady rain returns on Monday followed by a transition to off-and-on showers Monday evening. These showers linger into Tuesday and Wednesday maintaining cooler than normal temperatures. Beyond this point much drier and warmer summer-like conditions come roaring back into focus June 11-15 with increasing heat related concerns next weekend, especially across the inland valleys.

LONG TERM...Thursday through Saturday

Conditions are expected to dry out with temperatures trending towards seasonal normals on Thursday as high pressure slowly builds into the area from over the eastern Pacific. In stark contrast to the short term period, our focus shifts to a significant warming and drying trend Friday through next weekend. Cluster analysis for June 11-15 for 500 mb heights generally suggest upper level ridging will gradually amplify over the region. This will bring a prolonged stretch of dry weather, with temperatures likely warming each day before peaking sometime early the following week (Sun/Mon). However, there is still uncertainty in regards to exactly how warm temperatures will get, which could wind up anywhere in the mid 80s, 90s, or even near 100 for inland valleys. That said, confidence continues to increase for high temperatures of at least 90 degrees or warmer June 13-15. By June 15, probabilities for highs above 90 degrees peak near 60-80% for inland valleys per the latest NBM guidance, and less than 10% at the coast. With the increase in both daytime and nighttime temperatures, there is a 5-25% chance for major HeatRisk or higher Saturday June 13, a 20-50% chance Sunday June 14, and a 20-55% chance Monday June 15. Those who plan on swimming in lakes or rivers to cool down should be mindful of the dangers that come with cold water temperatures this time of year and/or swift currents. Anyone who is sensitive to heat and/or has outdoor plans June 12-15 should continue to pay attention to the forecast over the coming days as it continues to get refined and impacts further realized. -99/23

AVIATION

Largely VFR flying conditions are expected through the period. Low clouds this morning will tend to break up through the afternoon, while high cloud coverage will increase ahead of an approaching frontal system. Light winds this morning will rise to 5-10 kt out of the west to northwest along the coast, and out of the north inland, then ease below 5 kt again tonight. Cigs lower overnight before rain arrives from the west by 12-15z Mon, with southerly winds rising to 5-10 kt ahead of the frontal boundary. Chances for MVFR cigs will increase to 25-45% along the coast and 15-25% at inland terminals after 15z Mon.

KPDX AND APPROACHES...VFR conditions expected throughout the period. Low cloud coverage will tend to decrease by this afternoon while high cloud coverage increases from the west, followed by rain beginning by 13-15z Mon. North to northwest winds around 5 kt today will ease overnight, then rise out of the south near 5 kt Monday morning ahead of the frontal boundary. Chances for MVFR cigs increase to 20-25% by 17-18z Mon. -36

MARINE

Headed through the middle of the week a progressive weather pattern facilitates periods of rain and increased winds at times before high pressure returns towards the weekend. However, for much of today the coastal waters remain in a lull between frontal systems as a shortwave ridge of high pressure passes overhead. Starting this evening, southerly winds begin to increase ahead of our next weather disturbance with wind gust up to 20-30 knots peaking Monday morning. Thus, Small Craft Advisories have been issued for both the inner and outer waters through Monday afternoon/evening. Seas of 4-8 ft at 8-10 seconds continue during this time period with a dominant westerly swell. A secondary frontal system Monday night into Tuesday leads to a switch to west-northwesterly winds and gusts generally hold between 13-20 knots into wednesday.

Beyond midweek, there is high confidence that high pressure will build offshore, turning winds northerly over the coastal waters. Diurnal winds will peak in the afternoon and evening, reaching 15-25 kt with wind gusts near 30 kt, especially for locations off the central Oregon coast. Seas of 6-8 ft at 10 seconds with a dominant westerly swell look to continue as well. -99

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.

WA...None.

PZ...Small Craft Advisory from 5 AM to 5 PM PDT Monday for PZZ251.

Small Craft Advisory from 5 AM to 11 PM PDT Monday for PZZ252- 253.

Small Craft Advisory from 11 PM this evening to 5 PM PDT Monday for PZZ271.

Small Craft Advisory from 11 PM this evening to 11 PM PDT Monday for PZZ272-273.