Area Forecast Discussion
Issued by NWS Portland, OR
Issued by NWS Portland, OR
087 FXUS66 KPQR 062220 AFDPQR Area Forecast Discussion National Weather Service Portland OR 220 PM PST Mon Jan 6 2025 .SYNOPSIS...A ridge of high pressure will bring dry conditions through most of the week. One exception is Tuesday night into Wednesday morning, where a weak front may bring some light precipitation to the coast and southwest Washington. Otherwise, conditions should remain dry and at seasonably normal temperatures until Thursday night. Expect rain to return early Friday morning as a low pressure system moving towards Alaska/British Columbia drags an extended frontal system towards the Pacific Northwest. && .DISCUSSION...Today through Sunday...A ridge of high pressure builds into the region, bringing benign weather with dry and seasonably normal temperatures. Expect for this ridge pattern to dominate through most of the week, keeping max temperatures in the low 50s through Thursday. Tonight, winds in the Columbia Gorge will begin to increase, with gusts around 35-40 mph until late Tuesday afternoon, gusting up to 45 mph Tuesday morning. One exception to the expected dry pattern this week will be Tuesday night, where a weakening front will bring light precipitation to most of the coast and southwest Washington. Rain conditions should end Wednesday morning before morning commute. With an increase in insulating cloud cover due to this weakening front, expect high temperatures in the mid to upper 40s for Tuesday. Thursday, a low pressure system will shift northeastward towards Alaska/British Columbia, dragging an extended frontal system towards the Pacific Northwest. Timing of arrival still remains uncertain, with yesterday suggesting arrival time late Thursday and today suggesting arrival time around early Friday morning. This system is expected to bring rain through Friday into Saturday, with snow/rain in the Cascades. Furthermore, this weekend will slightly cool, with high temperatures in the mid to upper 40s expected. ~Hall && .AVIATION...Generally VFR conditions are overhead this afternoon as the last of the low stratus in the southern Willamette Valley is beginning to clear. We`ll continue to maintain VFR conditions this evening, however, for locations sheltered from easterly winds through the Columbia River Gorge we`ll need to keep an eye out for sunrise fog formation and thus LIFR conditions. Based on HREF guidance confidence is highest for fog formation in the central and southern Willamette Valley, but given the setup fog is possible in the Tualatin Valley(KHIO) as well. As the morning goes on any fog likely transitions to a low stratus deck before dissipating midday/early afternoon - VFR conditions return. Lowest confidence on the timing of fog dissipation in the southern Willamette Valley (KEUG) which may take until the mid afternoon hours. PDX AND APPROACHES...VFR conditions likely persist through the TAF period. Expect mainly easterly winds less than 7-15 knots, although late tonight into sunrise Tuesday morning they may become more variable with a northwesterly component. -Schuldt && .MARINE...High pressure now presides across the region facilitating offshore winds and calmer conditions across the inner and outer waters. Expect these offshore winds to generally persist through the day Tuesday. Gusts will be sporadic at times but remain less than 20-25 kts - highest around the coastal gaps. Seas hold around 7-9 ft with a higher period of 16-18 seconds although there may be a brief period this evening where significant wave heights approach 10 feet across the outer waters thanks to the arrival of a fresh westerly swell. Due to the marginal nature of this set-up have opted to forego issuing any small craft advisories. Then late Tuesday into Wednesday morning a weak weather system passing to the north will clip the waters, switching winds briefly southerly and bringing another fresh westerly swell that will increase seas to 9-12 ft through Wednesday afternoon. After a break on Thursday the next weather system looks to be Friday, bringing Small Craft winds and seas near 13-16 ft at 13-15 seconds. -Schuldt/HEC && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...None. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland