textproduct: Medford

UPDATE

Aviation Discussion Updated.

AVIATION (00Z TAFs)

An upper level low off the California coast will keep bringing high clouds to the region tonight. We still expect valley fog with LIFR visibilities and ceilings to develop for valleys west of the Cascades overnight and persist into Wednesday morning, and for some areas into the afternoon. Roseburg and Grants Pass may see LIFR conditions through the TAF period. Medford is expected to see fog and LIFR develop in the early morning on Wednesday. East of the Cascades expect VFR conditions. Along the coast, areas of fog are expected overnight and into Wednesday morning with LIFR ceilings and a mix of IFR/LIFR visibilities. These conditions will lift in the afternoon Wednesday.

PREV DISCUSSION

/Issued 235 PM PST Tue Jan 20 2026/

DISCUSSION...Persistent high pressure aloft remains over the eastern Pacific just offshore of the BC coast today, and this has essentially kept the storm door closed to the West Coast. Dry conditions will continue through the forecast period with the majority of ensemble members maintaining these dry conditions until the last few days of the month. Overall, only subtle changes in the day to day conditions are expected for the next week.

While we won't completely lose the ridge pattern, a subtle pattern change is expected tomorrow, which could be considered the start of an overall breakdown of this persistent ridging pattern. A weak low pressure system will undercut the strong ridge that has been in place for the past week or more and gradually move south and eastward toward the California Coast. We'll be on the northern/northeastern periphery of this low and we'll see some increased mid-level moisture push into the region. Expect some increased cloud cover on Wednesday as well a slight tick upward in daytime humidities for the midslopes/ridges. Additionally, there should be some better mixing by Wednesday afternoon, which could bring at least a slight improvement to the stagnant conditions across West Side Valleys tomorrow. We'll be letting the Air Stagnation Advisory expire Wednesday afternoon for West Side Valleys, but have decided to extend for another day for valleys east of the Cascades as mixing doesn't really improve much until Thursday afternoon. Nightly rounds of fog/freezing will continue to redevelop in the same places each morning, and we've gone ahead with another freezing fog/dense fog advisory for tonight into Wednesday morning.

What little effects we get from this low pressure system will dwindle as this low move off to the south an east by Thursday afternoon. The region will remain in north to northwest flow through the weekend as the ridge rebuilds over the eastern Pacific, albeit weaker this time. Some weak shortwaves will slide down the backside of this ridge. We don't expect much to amount from these shortwaves, but expect some increased cloud cover, slightly cooler temperatures and at least slightly improved air quality as mixing remains somewhat improved. This ridge will remain in place into early next week, but stronger systems approaching from the west will continue to weaken the ridge pattern. Ensembles continue to show the potential return to active weather towards the latter half of next week (January 28th-30th) into early February.

MARINE...Updated 300 PM PST Tuesday, January 20, 2026...Below advisory seas remain in the forecast for area waters through Wednesday. Winds turn dominate from the north on Wednesday, and speeds will increase Wednesday night through Thursday. These strong northerly winds will generate some steep wind waves Thursday night south of Port Orford and beyond 10 nm from shore. Seas will be relatively lower farther inland and to the north. These steep wind waves are expected to reach 10 feet at about 7 to 8 seconds Thursday night. These seas will likely remain hazardous to small crafts into Saturday morning.

-Smith

MFR WATCHES/WARNINGS/ADVISORIES

OR...Air Stagnation Advisory until 4 PM PST Wednesday for ORZ023-024- 026-029>031.

Dense Fog Advisory until 10 AM PST Wednesday for ORZ023.

Freezing Fog Advisory until noon PST Wednesday for ORZ024.

CA...None.

PACIFIC COASTAL WATERS...Hazardous Seas Watch from Thursday afternoon through late Friday night for PZZ376.