textproduct: Medford

DISCUSSION

Much like yesterday at this time, satellite image shows low clouds persisting in the Rogue, Illinois, and Shasta Valleys. Low clouds are gradually burning off in the Klamath River and Scott Valleys and the Umpqua Basin. Elsewhere it's clear and will remain clear through this evening. It's likely the low clouds will persist Rogue and Illinois Valley through the afternoon and tonight. What this will do it limit or even prevent fog from forming in these areas later tonight. However, low clouds and fog are likely again in the valleys in Douglas county, Scott, Klamath River, and Shasta Valley late this evening through Saturday morning.

Meanwhile, low clouds and fog should burn off late this afternoon in the Shasta Valley, only to re-form again late this evening and lasting through at least early Saturday afternoon.

The overall pattern is not going to change much through Saturday with strong upper ridging keeping the storm track well north of the forecast area. This means continued dry and mild weather (where low clouds and fog are absent). The low clouds and fog for the areas mentioned above will keep afternoon temperatures in check today and Saturday and they have been adjusted lower to reflect this. It's not out of the question low clouds in the Rogue and Illinois Valley will persist through Saturday afternoon as well.

The upper ridge will weaken slightly as a weak front moves in from the west Sunday. given the weak shortwave and surface front will be running into the stronger upper ridging, the most likely scenario is the front will weaken and dissipate as it reaches the coast Sunday afternoon. Per the usual the NBM solution is too bullish (meaning pops are too high and too far inland) which does not add up given the above mentioned. To further support this thinking, the majority of the individual ensemble members also show the front weakening and dissipating as it reaches the coast and inland.

Sunday is likely to end up being the last quiet day of the forecast period. The operational models and ensembles have been showing for the past few days a more active pattern setting up by the start of next week. In a relative sense, it will seem like a significant change with bouts of moderate to heavy rain and mountain snow along with moderate to strong winds possible at the coast, and east of the Cascades on Monday. However, it's not all that unusual to have active weather of this magnitude this time of the year.

The first front will arrive at the coast early Monday morning bringing rain and moderate to occasionally strong winds to the coast, north of Cape Blanco. Precipitation will move inland during the day Monday, with winds increasing east of the Cascades.

The change in the pattern is one where we'll see a parade of front moving through the area from Monday-Friday next week bringing more rain, mountain snow and moderate to occasionally strong winds.

The main issue will be the timing and exact track of of each individual system which is likely to vary from day to day.

Looking beyond next week leading up to Christmas Holiday, there's increasing 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 into Christmas week.

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...12/18z TAFs

Very little change in the pattern is likely in the next 24 hours. Areas of low stratus and fog are present in valleys west of the Cascades, including IFR in the Rogue Valley at Medford and Grants Pass and LIFR in fog in the Shasta Valley, and the Umpqua Basin, including Roseburg and Coquille valleys. These conditions will persist through 20z. Some areas, such as Medford and Grants Pass will see ceilings lift higher late in the afternoon to MVFR, but likely will not break out.

Along the coast and just offshore. VFR conditions are likely through early this evening with lower flight conditions are likely to return tonight.

East of the Cascades, Freezing fog is confined to portions of Klamath Basin, including Klamath Falls, but satellite and web cams suggest the freezing fog and vertical visibility are shallow and it could clear out within the next hour or two, with VFR conditions the rest of the day. Guidance suggest freezing fog and low vertical visibility could develop again late this evening and last for the rest of the TAF period. -Petrucelli

MARINE...Updated 100 PM PST Friday, December 12, 2025

Light to moderate north winds and a moderate west swell will persist through tonight. Winds gradually shift to southerly on Saturday then increase as the day progresses on Sunday. Conditions are likely to remain below advisory criteria through Sunday afternoon, but a brief period of steep seas is possible north of Cape Arago early Sunday.

Worsening conditions are expected early next week as low pressure deepens over the north Pacific and a cold front swings through the waters Sunday night into Monday. More widespread advisory level conditions are expected to return late Sunday into Monday, with a high probability of gales (>70%) and a period of steep to very steep hazardous seas likely by early Monday morning. Additional frontal systems will maintain weather active with elevated winds and seas through much of next week. /BR-y

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.