textproduct: Portland

SYNOPSIS

Warm and dry conditions continue through at least Monday. An upper level low is expected to develop off the PacNW coast during the latter half of the weekend. Uncertainty remains in the forecast heading into Tuesday regarding the position of the upper low. Confidence is higher that conditions turn cool and wet on Wednesday.

LONG TERM...Monday through Friday

The aforementioned trough will slow its eastward progression on Sunday, eventually pinching off from the main upper level flow into a closed low off the PacNW coast on Sunday. This feature becomes more influential heading into the next work week. Cluster analysis shows increased agreement for Monday with the center of the closed low remaining off northern California. That said, increasing cloud cover is still expected as heights aloft decrease over the area. Mild temperatures are still expected with highs in the upper 60s to low 70s inland and upper 50s to low 60s along the coast.

Come Tuesday, there remains some uncertainty among the ensembles. Trends point toward the upper low beginning to shift onshore which would bring cooler temperatures and increasing PoPs over the region. However, there is still a ~70-30 split among the ensembles favoring this progression which means there is still chance for mild and dry conditions. Locations farther south and west will see the transition to cooler, wetter conditions earlier given the location of the upper low. There is much better agreement for Tuesday night into Wednesday being cool and wet. Cluster analysis shows good agreement in the closed low moving east and becoming an open wave. Ridging begin building back into the region Thursday and Friday, supporting a warming trend along with drier conditions. -19

AVIATION

High pressure will maintain widespread VFR flight conditions through 18Z Sunday with scattered high clouds around 20-25 kft. Winds will remain light and variable less than 5 kt, with one exception. Easterly winds at KTTD will remain breezy through at least 20-21Z Saturday with gusts up to 20-25 kt before east winds decrease in strength between 21-00Z. KPDX will also see a light easterly wind at times through 21-23Z Saturday before winds become light and variable again thereafter. Expect easterly winds to restrengthen a bit between 12-18Z Sunday at both KTTD and KPDX, beginning at KTTD first.

KPDX AND APPROACHES...Scattered high clouds with cigs above 20-25 kft will maintain VFR flight conditions through 18Z Sunday. Expect light easterly winds under 7 kt through 21-23Z Saturday before winds become light and variable under 5 kt. Expect easterly winds to restrengthen towards 17Z Sunday with sustained wind speeds approaching 10 kt. -23

MARINE

Benign conditions continue through the weekend. Southerly winds up to around 10 kt expected today with seas remaining less than 5 ft.

There is higher forecast uncertainty for winds and seas early next week as an area of low pressure offshore approaches the coast. The placement of the low will determine the conditions across the waters, with the forecast at this lead time favoring increasing onshore flow through Wednesday, when WNW gusts may reach 20-25 kt beyond 30 NM. Higher winds and a freshly arriving NW swell may push seas to 10-12 ft Wednesday into Thursday.

Very strong ebb currents will continue across the Columbia River Bar each morning through Tuesday. With seas expected to build slightly by early next week, a steep ebb chop may necessitate Small Craft Advisories in the hours around peak flow each day. -19/36

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...None.