textproduct: Portland

SYNOPSIS

A frontal system will continue to bring widespread rainfall to the Pacific Northwest this weekend, although snow levels remain above the Cascade passes through Sunday. Cooler and showery weather then continues Sunday night into early next week, with light snow accumulations at pass-level. A drier pattern returns midweek before rain chances increase late in the week.

LONG TERM...Monday through Friday

The cold front is expected to move through the area late Sunday evening with shower activity continuing in the post-frontal environment. Snow levels will also drop below pass level, generally 3000-4000 feet by Monday morning. Light, sub-advisory criteria accumulations are expected with a low (10-20%) of exceeding 6 inches in 24 hours through Monday evening. Models did come up slightly on these probabilities so something to keep in mind and watch for changes as the system progresses. Shower activity diminishes Monday night as drier air moves in and heights increase.

Ensembles show good agreement in a dry period Tuesday through Thursday as shortwave ridging moves in overhead. Seasonable temperatures are expected through much of the work week. Models show signs that the dry pattern breaks down again late next week and into the weekend but exact timing and precipitation details are unclear at this times. -19

AVIATION

A incoming system will continue to bring deteriorating flying conditions and widespread rain across the airspace. Expect a mixture of MVFR/IFR conditions along the coast, with around a 20% chance for periods of LIFR conditions. The current VFR flying conditions inland will persist through around 00Z Sunday, afterwards conditions are expected to become predominately MVFR. Starting around 04Z-06Z Sunday, there is a 20-40% chance for IFR conditions to develop for inland locations. Overall, expect lowered flight conditions to continue developing with predominately MVFR expected across the airspace with intermittent IFR/LIFR conditions.

Easterly winds around 10-15 kt continue in the Portland area, with gusts to 30 kt at KTTD. Expect southerly winds to slowly develop across the airspace as the front, that is bringing the rain and lowered flight conditions continue to trek eastward. Low-level wind shear up to 50 kt out of the south-southwest along the coast and KTTD are likely as the frontal boundary passes through the early afternoon for coastal locations and from the afternoon through the early evening for KTTD.

KPDX AND APPROACHES...VFR conditions, east winds and rain continue through this morning. Winds expected to become more southerly at 5-10 kt through the late afternoon. Flight conditions are expected to fall towards MVFR starting around 00Z Sunday, with these lowered flight conditions are expected to persist through at least 06Z Sunday. Starting around 05Z Sunday, there is a 10-25% chance for IFR conditions to develop at or near the terminal. /42

MARINE

A system moving through the waters tonight will keep an active conditions across all waters. As the system continues to move inland, expect southerly gusts up to 30 kt with intermittent gusts up to 40 kt possible (60-90%) through around 8PM tonight. Seas will also remain elevated around 9 to 14 ft at 12 to 14 seconds. As the system moves further inland, look for southerly winds to become westerly, before becoming easterly late tonight. A quick moving disturbance on Sunday will bring a short period of north/northwesterly winds, before returning to a more traditional westerly pattern by Monday. Seas during this time frame will also remain elevated as a fresh westerly swell returns to all waters. This will keep seas above 10 ft through at least the middle of next week. Therefore, have extended the current suite of Small Craft Advisories through at least Sunday evening.

Weak high pressure returns by the middle of the week and will provide a lull in the active weather with conditions falling below Small Craft Advisory thresholds. However, this looks to be short lived as a broad, upper level low looks to dive southward out of the Gulf of Alaska. This system currently, looks to bring elevated winds as well as seas building into the low to mid teens. /42

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.

WA...None.

PZ...Small Craft Advisory until 4 AM PST Monday for PZZ210-251>253- 271>273.