textproduct: Portland

SYNOPSIS

Seasonable weather continues through much of the week with a first weather system bringing chances for rain today into Monday and a second from Wednesday into Thursday. The latter part of this week looks to bring a drying trend through the weekend.

LONG TERM...Tuesday Night through Sunday

Another, broader closed upper low and its associated surface low will drop south from the Gulf of Alaska over Vancouver Island and into the Pacific Northwest Tuesday night into Wednesday morning. This will bring another round of cool temperatures and precipitation for the region through Friday. Even cooler air within the upper low will see seasonable temperatures continue, or even fall by a degree or two from earlier in the week. 850 mb temperatures look to drop towards 0C to -2 C, which will result in snow levels falling towards 3500 ft by Thursday morning. This is resulting in a 45-70% chance for another inch or more of snow at area Cascade Passes from Wednesday morning through Thursday night. At lower elevations, another 0.50-1.00 inches of rain may fall during this time. While the forecast trends drier as the upper low fills by this Saturday, it may still remain close enough to the region to support lingering rain showers for Halloween trick-or-treaters. At this point, there are 10-20% chances for light rain while temperatures fall through the 40s Saturday afternoon and evening, with higher confidence in dry weather by Sunday.

Now is the perfect time to check on any winter weather equipment and emergency supplies for your household and vehicles. /42-36

AVIATION...Through 12Z Tuesday

Moist, southwest flow will become more westerly through the day as a low pressure system slowly moves over the region. This low will maintain showery precipitation across the air space, resulting in a mixture of low-end VFR and high-end MVFR conditions with a 10-15% chance for intermittent IFR conditions at any given time through the TAF period across the airspace. MVFR conditions are expected to be the predominant flight category through the TAF period.

Southerly winds around 5-10 kt expected across the airspace with winds becoming more westerly along the coast around 20Z-22Z Monday and around 00Z Tuesday for inland locations.

KPDX AND APPROACHES...Showery precipitation through the TAF period will result in a mixture of low-end VFR and high-end MVFR conditions, with MVFR conditions expected to be the predominant flight category through the TAF period. Southerly winds will become more westerly after 00Z Tuesday. /42

MARINE

A slow-moving and steadily weakening area of low pressure will traverse waters through early this morning as it continues to slowly moving onshore through tonight. As this low pushes eastward, the currently southerly winds will slowly develop into a more north/northwest pattern as the day progresses, yielding widespread northwesterly flow by late tonight. Winds and seas will continue to ease through tonight as the low weakens and moves inland. Winds are expected to fall below 15 kt by this morning with seas of 5 to 7 ft.

A northwesterly swell begins to build late Tuesday into Wednesday as another system approaches from the Gulf of Alaska. There continues to be 5-20% chance for seas to reach or exceed 10 ft at any point Wednesday in the waters beyond 10 NM. For Thursday and beyond, winds are favored to ease below 10 kt while seas fall to 5 ft or less, with these conditions expected to persist into next weekend. /42

PQR WATCHES/WARNINGS/ADVISORIES

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