textproduct: Medford

DISCUSSION

The first in a series of fronts is moving into the area bringing rain to the coast and coastal mountains and gusty winds. Strongest north of Cape Blanco. Precipitation will spread farther inland, with winds increasing east of the Cascades. The bulk of the precipitation will be along the coast, coastal mountains and Cascades. Satellite image and radar are showing moderate to occasionally heavy precipitation with a few lightning strikes which is partially being aided by an upper level jet moving towards southwest Oregon. Isolated thunderstorms should remain confined to the south Oregon coast and inland in Curry and western Josephine County into early this evening.

Most of the Rogue Valley could end up dry during the day Monday with not much more than occasional showers late this afternoon and early evening due to the non-favorable southwest flow. East of the Cascades will likely get little to rainfall, but it will be windy into early this evening.

More fronts will follow the rest of the week into next weekend bringing more rain, moderate to strong winds and higher elevation mountains snow. Detail's on the timing mentioned below could vary with each individual storm, so be on the lookout for updates to the forecast in the days to come.

A second and stronger system will arrive Tuesday night into Wednesday brining moderate to heavy rain to the coast, coastal mountains and Cascades. Moderate to occasionally strong winds are possible at the coast. Not all of the ingredients are there for a winds to reach high wind warning criteria at the coast, but they do for east of the Cascades, especially near and at the ridges. guidance shows 700 mb winds between 60-70 kts Tuesday night through Wednesday morning, then decreasing some Wednesday afternoon. Given the above, the High Wind Watch has been upgraded to a High Wind Warning for the higher terrain in Lake, Modoc and potions of Klamth County. At the same time a Wind advisory has been issued to cover the remainder of Lake, Modoc and to include more of Klamath County. Please see NPWMFR for more details.

Snow levels will be between 7000-8000 feet Tuesday, then lowering between 4500-5500 feet Wednesday. Therefore we'll see rain change over to snow late Tuesday night into Wednesday morning with 3-5 inches possible up towards Willamette Pass, and 2-4 inches around Diamond and Crater Lake by late Wednesday morning.

Precipitation will gradually diminish later Wednesday morning through the afternoon and we'll catch a relative break in the action from Wednesday afternoon into most of Wednesday night.

A stronger storm will arrive Thursday and last through Thursday night bringing another round of moderate to heavy precipitation and strong winds. Strong winds will be a concern Thursday, especially east of the Cascades where some of the guidance shows 700 mb winds between 70-80 kts over a large chunk of real estate east of the Cascades. It's also worth noting, strong winds east of the Cascades could be of longer duration (12-18 hours).

Although not as high of a concern, moderate to strong winds will be a concern in the Shasta Valley. However the wind direction in the Shasta Valley has a westerly component which could put a cap on the magnitude of the winds. Guidance shows the Medford to Redding gradient between 8-9 mb. So it's something we'll have to keep a close watch on.

The coast is another story. Current gradients between Arcata and North Bend peak out at almost 10 mb Thursday afternoon and night which is significant enough for high winds, and guidance shows an enhanced area of strong winds close to 70 kts Thursday afternoon from about Cape Blanco north.

Thre's good agreement the storm that arrives Thursday will have an atmospheric river (AR) component, with a long fetch of moisture extending southwest towards 160W, with the source region coming from the tropics. Additionally, there is favorable upslope flow along the coastal mountains and Cascades. The net result could be a prolonged period (24-36 hours) of heavy precipitation for these areas along with moderate to occasionally heavy rainfall elsewhere. Given the lack of rain the last few weeks, rivers are pretty low, but they will come up over time and we could be looking at potential flooding on the Coquille towards the end of the week. Another factor that could put a cap on the flooding concerns is little to no snowpack. Therefore there will be no additional contribution from snowmelt going into the rivers. Another item worth noting is there are some indications the core of heavier precipitation could shift north of the Umpqua Divide for a brief period of time Thursday afternoon into Thursday night before shifting south over southern Oregon and Northern California Friday. Keep in mind the details could change, so keep a eye out for updates in the days to follow.

Looking into next week leading up to Christmas Holiday, there's strong evidence that's being supported by the ECMWF, GEFS ensemble means and clusters, we'll be heading into a colder and wet pattern with storms originating from the Gulf of Alaska as we get towards the following weekend through at least Christmas Day.

These typically result in colder temperatures, and precipitation with lower snow levels. The pattern shows below normal 500 mb anomalies with a stronger upper troughing in the western U.S. with ridging and above normal 500 mb anomalies in the northeastern part of the U.S. The anomalies being shown are pretty significant this far out which is unusual since they tend to "wash out" and lean more towards climatology.

This is a almost the opposite of the pattern we have experienced for almost the last three weeks, with stronger ridging in the western part of the U.S. and deep upper troughing in the northeastern part of the U.S. In other words, the switch basically gets flipped as the overall pattern changes. -Petrucelli

AVIATION...15/18z TAFs

The main concern ion the short term will be low level wind speed shear along the coast into early this afternoon, including North Bend. Stronger winds should surface at North Bend early this afternoon, and at the same time winds aloft will be diminishing, thus ending the concern for low level wind speed shear. MVFR and occasional IFR ceilings are expected in precipitation through the TAF period, although could not rule out brief periods of VFR ceilings this evening and tonight as the bulk of the precipitation shifts south, but confidence is not high enough to include improving conditions in the TAF.

Inland west of the Cascades, VFR ceilings are being observed and should last for most of the afternoon, the exception will be in Roseburg as the front moves south bringing lowering ceilings and partial mountain obscuration north of the Umpqua Divide between 21- 22z. The medford terminal should remain VFR through 0z, then ceilings will lower as the front moves in. Once the front moves south, there could be enough clearing along with a more stable atmosphere and ample low level moisture for low clouds and fog to develop late tonight into Tuesday morning for the Valleys, including the Roseburg and Medford terminals. The timing of when the lower conditions develop in the TAF could change, so watch for updates.

East of the Cascades, VFR conditions are expected through the TAF period, although the higher terrain could be partly obscured towards 0z, with ceilings possibly hovering towards 3000 feet at Klamath Falls for a few hours this evening. -Petrucelli

MARINE...Updated 100 PM PST Monday, December 15, 2025

The first round of south gales north of Cape Blanco is winding down this afternoon. Very steep and hazardous seas will remain elevated, but become less steep as they transition to swell dominated this evening and persist through much of Tuesday. The next front is expected late day Tuesday, bringing another round of southerly gales that quickly switch to the northwest, and remain strong, late Tuesday night. This will build seas again, becoming very steep and hazardous Tuesday night across all waters, with gales expected north of Cape Blanco.

Winds ease late Wednesday morning, but seas will remain steep through Wednesday night. Another, more persistent front will take aim at the coast late Wednesday night/early Thursday morning, bringing a longer duration of strong winds. Strong gales are likely with this system, with a 20-40% chance of storm force (>55kt) gusts possible north of Cape Blanco on Thursday morning. Winds will gradually ease from north to south late Thursday night into Friday morning, but seas are likely to remain steep to very steep through Friday. Moderate to heavy rain will accompany each front this week. /BR-y

MFR WATCHES/WARNINGS/ADVISORIES

OR...High Wind Warning from 10 PM Tuesday to 4 PM PST Wednesday for ORZ030-031.

Wind Advisory from 10 PM Tuesday to 4 PM PST Wednesday for ORZ029>031.

CA...High Wind Warning from 10 PM Tuesday to 4 PM PST Wednesday for CAZ085.

Wind Advisory from 10 PM Tuesday to 4 PM PST Wednesday for CAZ085.

PACIFIC COASTAL WATERS...Hazardous Seas Warning until 4 PM PST this afternoon for PZZ350-356-370-376.

Small Craft Advisory until 4 PM PST Tuesday for PZZ350-356-370- 376.

Gale Warning until 4 PM PST this afternoon for PZZ350-370.