textproduct: Portland

SYNOPSIS

Low pressure moving over the area will send a weak cold front through the area tonight. Expect near average daytime highs through the week. Ridging builds back into the area early next week, increasing temperatures back into the mid to upper 80s across the interior lowlands.

DISCUSSION...Tonight through Friday

An upper level trough will continue to progress northeast tonight, sending a weak cold front through the area. As the low moves further inland, zonal flow aloft will develop on Sunday. Zonal flow will maintain seasonal temperatures across the forecast area. Looking ahead through the early next week, ensemble clusters favor ridging over the central CONUS which will spread into the PacNW. As the ridge builds over the area, warmer temperature are expected to return Monday and Tuesday. There remains some uncertainly as to how warm the start of next week will be as the 10th-90th percentiles for daytime highs range from the mid 80s to low 90s for the interior lowlands on Monday and Tuesday. Clusters favor another trough influencing the region by mid-week but exact timing and upper level pattern are uncertain but onshore flow and seasonable or below average temperatures would be favored. When looking at Wednesday and Thursday, the 10th-90th percentiles range from the low 70s to low 80s. There is also no clear signal for any precipitation associated with the mid week trough. approximately 15-25% of members show very light rain possible during the Thursday-Friday timeframe but nothing significant at this time. /42-19

AVIATION

An upper-level low currently offshore continues moving north/northeast. This low has resulted in a mixture of MVFR and VFR conditions along with southerly winds across the airspace. Southerly winds are expected to persist, with the MVFR/VFR mixture inland continuing to slowly improve to predominately VFR conditions for all inland locations. These VFR conditions inland are expected to persist through at least 04Z-06Z Sunday. Afterwards, MVFR conditions are expected to return across all inland locations.

Coastal locations will maintain generally MVFR conditions through the TAF period. There is a low probability (10-20%) that brief periods of VFR conditions will continue to occur along the coast from through 00Z Sunday. Gusts approaching 25 kt expected along the coast through around 06Z Sunday.

KPDX AND APPROACHES...MVFR conditions will improve towards VFR through 22Z Saturday. Southerly winds expected to persist through the TAF period. Around 05Z-08Z MVFR conditions are expected to return and persist through the remainder of the TAF period. /42

MARINE

South to southwest winds continue through tonight as a low pressure system moves over the northeast Pacific. A cold front moves across all waters this evening, bringing a 50-80% chance for maximum wind gusts up to 25 kt for the inner waters and the Columbia River Bar. As a result, a Small Craft Advisory has been issued for the inner waters and the Columbia River Bar through 5 PM tonight. For the outer waters, chances are 20-40% with the highest values of that range between 10 and 30 NM.

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 5 PM PDT this afternoon for PZZ210- 251>253.