textproduct: Medford

DISCUSSION (Today through Wednesday)

Key Points:

* Change/New Development: Between now and 8am - Freezing Rain/Drizzle potential: - Highway 138 between Diamond Lake and Highway 97 - Highway 97 north of Highway 138 in Klamath County - 10-20% chance for very light icing (0.01"-0.02") - Hazardous driving conditions for morning commute * Today thru Friday night: Moderate to Isolated Major Impacts - Snow: Heaviest Friday into Friday night - Snow levels dropping to ~3500-4000ft Friday - Snow locations/amounts dont warrant advisories/warnings - Rain: Moderate to heavy rainfall for westside areas - Heaviest rainfall along Cascades and west - Widepsread flooding not expected - Minor Flood: Myrtle Point (South Fork Coquille River) - Forecast to go into minor flood stage Fri. night - Wind: Strong winds for coastal areas and eastside areas * Sunday - Monday - Moderate rainfall: coastal areas, northern Cali, and eastside - Light Snowfall for elevations mainly above 4500ft: - Mainly Cascades and northern California * Dec 24th/25th: - Snow levels dropping to around 4500 - Heavy rain potential for northern California - Heavy Snow potential for Mount Shasta and western Siskiyou

Further Details:

A notable change has occured from previous forecast. There is a very small chance for freezing rain/drizzle with light ice accumulations (0.01"-0.02") around Crater Lake (Highway 138) and areas north along highway 97 from Highway 138 (Klamath County). Any ice accumulation will create hazardous driving conditions. While this is a low end chance, it is a notable update given the risk of ice on roads. The surface temperatures will be the biggest factor in accumulations. Forecast soundings do show a warm nose above surface temperatures that briefly drop to around freezing; however, surface temperatures will be the biggest limiting factor here for ice accumulations. Surface temperatures are expected to be above freezing for these areas by late morning, so the window of opportunity is small. Nevertheless, felt worthy of discussion given the potential impacts with increased travel for the holidays.

We continue to see persistent troughing over/near the Gulf of Alaska with smaller pieces of energy kicking out ahead of this main area of low pressure. This will continue to bring rounds of precipitation across the region which may result in moderate to isolated heavy rain, light snowfall, and strong wind speeds/gusts. A pattern change could evolve around middle of next week.

Snowfall Thursday through Friday night continues to indicate relatively light accumulations at the forecast elevations and therefore limited impacts. However, rainfall amounts will still be notable as another atmospheric river event begins to unfold across the region. While widespread flooding is not anticipated, there may be isolated areas of nuisance type flooding as rivers are currently running low. That said, indications continue for minor river flooding at Myrtle Point (South Fork Coquille River) which could go into Minor Flood stage Friday night (~10pm). Additionally, Powers (South Fork Coquille River) could go into action stage (below Minor Flood stage). The forecast for Roseburg at Deer Creek has decreased significantly, and is no longer forecast to go into action stage. The heaviest rainfall through this stretch will be for westside areas, especially along/near the coast, as well as the Cascades before the switch over to snow. Timing for highest amounts will be Thursday night through Friday afternoon. Rivers may take a while to "react" to rainfall, so we could see delays in some river rises.

During this stretch (Today-Friday night), probabilities for 1.00" or greater over 6 hrs is roughly 60%-95% for all of Curry County, western Josephine County, most of Coos County, higher elevations of Douglas County (outskirts near county line), and Cascades before switch over to snow Fri/Fri night. Fortunately, this is over a long period, and our rivers are running low, so flooding potential will remain low with only isolated river flooding expected. If rivers were running higher, and this rainfall came in a shorter time period, we may have a different story on our hands.

Regarding snowfall Thursday through Friday night, we continue to see light snowfall amounts. Ensemble data continues to show a tighter spread and these trends have increased confidence that impacts will remain limited/minor. In other words, not expecting any advisories or warnings for snowfall Thursday/Friday.

Thereafter, moderate rainfall amounts expected Sunday into Monday, especially northern California. Snow amounts through this stretch do not look impactful and will be limited to higher elevations.

Around Christmas Eve/Christmas, there is increasing confidence for impactful rain in addition to potential snowfall across northern California. This will coincide with the pattern change as a stronger upper low develops off the coast of California. There will be an associated strong surface low as well. Models are in pretty good agreement here, so we could have travel concerns around this timeframe for heavy rain. At this time, it doesn't look like impacts for snow will be too concerning given snow levels around 4500 feet, but that is not certain at this time.

-Guerrero

AVIATION18/18Z TAFs

Along the coast and just offshore. A strong storm will bring moderate to strong winds along the coast and offshore. Winds aloft are very strong and there is enough difference in wind speed and direction for low level wind speed and directional shear to continue through this evening. Moderate to strong winds are likely to continue through 12z tomorrow, but winds aloft should gradually diminish late this evening and tonight. Ceilings will see saw back and forth between IFR and MVFR for most of the TAF period. The exception is at North Bend where VFR ceilings are expected for the start of the TAF period, then lowering this afternoon and tonight.

Inland, west of the Cascades, moderate to strong winds aloft will result in low level wind speed and directional shear despite the stronger surface winds at Roseburg. Stronger winds are likely to surface at Medford, but not until later this afternoon with gusts up to 30 kts possible this evening (3-5z). With the core of the heavier rain to the north, ceilings will remain VFR through this evening, then lowering from north to south. Medford could remain VFR for most of the TAf period, but have kept in the lower conditions towards 15z.

East of the Cascades, strong winds will be the main concern this afternoon through tonight for most locations, including Klamath Falls, guidance shows southwest wind gusts peaking out just over 30 kts this evening, but suspect this is underdone and we'll keep gusts at 35 kts in the Klamath Falls TAF. Winds should back towards the south late this evening and tomorrow and gradually diminish. Ceilings will remain VFR, although the higher terrain could end up partly obscured this afternoon, and more likely late tonight into tomorrow morning. -Petrucelli

MARINE...Update 330 AM PST Thursday, December 18, 2025

A strong front will move through the region late today/tonight, and conditions will quickly deteriorate today through Friday. Winds will quickly ramp up to widespread gales, with storm force winds developing from Gold Beach northward within 40 nm from shore. Expect widespread south winds of 30 to 40 kt with gusts around 50 kt, with storm force winds of 40 to 45 kt and gusts around 60 kt. Wind driven seas will become very steep and chaotic at 18 to 24 ft. A Storm Force Warning remains in effect this morning through Thursday evening, with a Gale Warning in effect for all other areas.

The front will move southeast over the marine waters tonight with winds shifting from south to northwest and diminishing, first over the northern waters, then in the southern waters by Friday morning. Wind speeds will be much weaker Friday morning behind the front (compared to today) and will remain relatively lighter through the weekend. Seas are expected to remain elevated Friday morning, then they will also gradually diminish later Friday afternoon into the weekend. Lastly, It's also worth noting, moderate to heavy rain will accompany both fronts resulting in limited visibility.

BEACH HAZARDS/HIGH SURF

A strong storm will bring storm force winds to the marine waters and strong damaging winds to the coast today. These winds will build very steep ocean waves that will result in large breaking waves of 20 to 25 ft in the surf zone. This will lead to hazardous beach conditions today for area beaches from Port Orford northward. If you have plans to visit area beaches today, stay away from the surf zone during this time as beaches and shorelines will become dangerous places. Jetties, rocks and logs are NOT safe. Inundation of low lying areas is possible and this could result in beach erosion or damage to exposed infrastructure.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Wind Advisory from 1 PM this afternoon to 4 AM PST Friday for ORZ023>025-029>031.

High Wind Warning from 10 AM this morning to 4 PM PST Friday for ORZ021-022-030-031.

High Surf Advisory from 10 AM this morning to 10 PM PST this evening for ORZ021.

CA...Wind Advisory from 1 PM this afternoon to 4 AM PST Friday for CAZ081-084-085.

High Wind Warning from 10 AM this morning to 4 PM PST Friday for CAZ085.

PACIFIC COASTAL WATERS...Hazardous Seas Warning until 4 AM PST early this morning for PZZ350-356-370-376.

Gale Warning until 1 AM PST Friday for PZZ350-356-370-376.

Storm Warning until 7 PM PST this evening for PZZ350-356-370- 376.