textproduct: Portland

SYNOPSIS

Showers are expected to diminish by sunrise this morning as high pressure begins to build over region. An upper level ridge building over the NE Pacific will yield a warming and drying trend through the week. Weak upper shortwaves may continue to track overhead as the ridge amplifies and shifts eastward, but chances for rain through the work week remain less than 5%. Probabilities for inland temperatures warming into the 80s increases to around 15-35% late this week.

DISCUSSION...Now through Saturday

A few lingering showers continue early this morning as the upper level trough shifts south, but expect dry conditions by sunrise. Despite increasing sunshine this afternoon, temperatures will still remain seasonably on the cool side, with highs expected into the mid-60s inland. An upper level shortwave ridge over the NE Pacific will slide over the region today, followed by a dry shortwave trough tonight, which will maintain slightly cooler conditions. By Monday afternoon, the upper ridge builds back over the NE Pacific with northwest flow persisting over the region through Tuesday. This should allow for mid to high level clouds to stream across the area, limiting solar heating somewhat. But, temperatures are expected to return to seasonable normals with highs around 70 degrees inland and in the lower 60s at the coast.

Cluster mean analysis of the ensembles shows good agreement of the upper ridge shifting eastward into the Pacific NW on Wednesday. This corresponds with the NBM's forecast of temperatures warming another 2-6 degrees F by mid-week. But, uncertainty in the eastward progression of the ridge axis supports increasing uncertainty in potential high temperatures later in the week. Chances to exceed 80 degrees rise to 15-35% within inland valleys on Thursday and Friday, with a more eastward ridge axis favoring a warmer solution, while a more offshore ridge axis may maintain onshore flow and cooler temperatures. Further uncertainty into early next weekend, but probs for exceeding 80 degrees does increase to around 30-50% for Saturday. 36/DH

AVIATION

Northerly flow aloft will continue to dry as the upper trough east of the Cascades drops south and high pressure builds over the region. Predominately VFR conditions are expected as showers move out of the area this morning. Though, lingering low level clouds may produce MVFR conditions briefly this morning, as there is around a 10-30% chance for MVFR CIGs through 18z, with highest probs at KTTD. As clouds continue to scatter out by Sunday afternoon, north to northwesterly winds are expected to become breezy, with gusts up to 20-25 kt at KONP and KEUG. Chances for marine stratus pushing onshore this evening increase to over 50% by 04-06z Monday at KAST.

KPDX AND APPROACHES...Predominately VFR expected through this evening. There is around a 20-30% chance for MVFR stratus with CIGs around FL025 through 18z this morning. Light winds become northwesterly around 8-10 kt this afternoon. /DH

MARINE

High pressure offshore will shift back over the coastal waters returning north to northwesterly winds today. Northerlies are expected to persist through much of next week as the summer- like pattern settles in. Strongest winds are expected during the afternoon and evening periods as a surface thermal trough strengthens over the southern Oregon coast. A Small Craft Advisory is in effect for the coastal waters south of Cape Foulweather later this afternoon through the early evening hours for gusts up to 25 kt. Similar conditions are expected on Monday. Winds are likely to increase toward the middle of the week. Seas around 8 to 9 ft this morning are expected to continue to gradually subside to around 6 to 7 ft on Monday.

The Small Craft Advisory for the Columbia River Bar remains through 8 am for a very strong ebb current expected to peak around 530 am this morning. Strong ebb currents for the Columbia River Bar are expected during the morning hours into next week, potentially yielding steep and hazardous seas for small craft crossing area bars through much of the week. /DH

PQR WATCHES/WARNINGS/ADVISORIES

OR...Winter Weather Advisory until 5 AM PDT early this morning for ORZ126>128.

WA...Winter Weather Advisory until 5 AM PDT early this morning for WAZ211.

PZ...Small Craft Advisory until 8 AM PDT this morning for PZZ210.

Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for PZZ253-273.