textproduct: Medford

DISCUSSION (Today through Tuesday)

Key Points:

* Today/Tonight: Minor Impacts - Moderate rainfall tapering off late this morning - Snow level continue to drop this morning - Light snowfall amounts as moisture tapers off - Cascades north of Highway 140 - Strong winds for eastside areas of Oregon * Thursday to Friday night: Moderate to Isolated Major Impacts - Snow: Heaviest Friday into Friday night - Cascades north of Highway 140 - Snow levels dropping to ~3500-4000ft Friday night - Snow amounts continue to be on the low end - Rain: Moderate to heavy rainfall for westside areas - Heaviest rainfall along and near the coast - Widepsread flooding not expected - Minor Flood: Myrtle Point (South Fork Coquille River) - Forecast to go into minor flood stage Sat. night - Wind: Strong winds for coast 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

Further Details:

The overall upper level pattern continues to show persistent troughing over/near the Gulf of Alaska with smaller pieces of energy kicking out ahead of this main low pressure area. 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.

Today, snow levels drop low enough to allow accumulations for areas at 4000 feet and above; however, we will also see QPF significantly lowering during this time. Still not expecting notable snowfall accumulations as these amounts will be relatively light. The bigger impact will likely be the strong wind speeds for eastside areas and northern California (Modoc County). Wind advisories and warnings are in place across eastside areas. Wind speeds will likely be strongest this morning with speeds dropping off through the afternoon hours. The advisories/warnings go through 4pm, but we could see hazardous conditions ending before 4pm as winds look to taper off late this morning.

Snowfall Thursday through Friday night continues to indicate relatively light accumulations, but 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, there are now indications for isolated river flooding at Myrtle Point (South Fork Coquille River) which could go into Minor Flood stage Friday night. Additionally, Powers (South Fork Coquille River) and Deer Creek at Roseburg could both go into action stage. Roseburg will be close to Minor Flood stage Friday morning. Overall, we will continue to monitor as additional rainfall could cause further fluctuations in river stages and forecast river stages. The heaviest rainfall through this stretch will be for westside areas, especially along/near the coast. 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, the probability for 0.50"/6hr will be about 70%-90% for westside areas, especially Curry, Coos, Douglas, and Josephine counties. These probabilities have increased notably from 24 hours ago. This is one of the reason why we are seeing higher forecast river stages given these higher QPF probabilities. Isolated areas in Curry County could see 4 inches of rainfall over 24-36 hours from roughly Thursday afternoon/evening through Friday evening. However, many westside areas could see 1-2 inches of rainfall through this stretch.

Regarding snowfall Thursday through Friday night, we continue to see light snowfall amounts. Ensemble data now shows a tighter spread in amounts, but there still remains some uncertainty. However, recent trends have increased confidence that impacts will remain limited/minor. In other words, not expecting any advisories or warnings for the second round of 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. Overall, not expecting any notable impacts through this stretch unless further QPF results in higher river stages or continue flood stages. That said, forecast river stages are expected to fall below any action stages Sunday into early next week, so at this time we are not seeing any secondary rises or continued flood stages.

-Guerrero

AVIATION (12Z TAFs)

Forecast soundings indicate low level wind shear is coming to an end; as a result, decided to remove this from the 12Z cycle as winds aloft ease. Otherwise, rainfall continues across the area, along with low clouds and some minor visibility restrictions. Overall, a mix of MVFR and IFR will continue through early parts of this cycle with predominately MVFR conditions expected by this afternoon. In fact, periods of VFR will be possible as rainfall comes to an end early this afternoon. Rainfall chances return tonight which will likely result in MVFR returning to the area. Lastly, low level wind shear could return Thursday morning which may be reflected in subsequent TAFs.

-Guerrero

MARINE

Updated 300 AM PST Wednesday, December 17, 2025...Active weather will continue through most this week.

A front moving through the area will shift winds to the west and gradually diminish through today. However, seas will remain very steep with a Hazardous Seas Warning continuing through tonight and into Thursday morning.

The next storm will be stronger and there's good agreement for a coastal jet forming along the coast, roughly from Port Orford north and out to 30 nm from shore early Thursday morning and lasting into Thursday evening. Probabilities from the HREF show a 90%-100% chance for at least 60 mph winds across this aforementioned area. As a a result, a Storm Watch has been issued. Where storm force winds are not expected there will be solid gales for the remainder of the waters from early Thursday morning into Thursday evening and a Gale Watch has been issued.

The front will move southeast into the marine waters Thursday night with winds shifting from south to northwest and diminishing, first over the northern waters, then towards Friday morning in the southern waters. In a relative sense, winds will be lighter later Friday morning into 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.

MFR WATCHES/WARNINGS/ADVISORIES

OR...High Wind Warning until 4 PM PST this afternoon for ORZ030-031.

Wind Advisory until 4 PM PST this afternoon for ORZ029>031.

High Wind Watch from Thursday morning through Friday morning for ORZ021-022-030-031.

CA...High Wind Warning until 4 PM PST this afternoon for CAZ085.

Wind Advisory until 4 PM PST this afternoon for CAZ085.

High Wind Watch from Thursday morning through Friday morning for CAZ085.

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

Gale Watch from late tonight through Thursday evening for PZZ350- 356-370-376.

Storm Watch from late tonight through Thursday evening for PZZ350-356-370-376.