textproduct: Medford

UPDATE

A strong and moist front is moving inland tonight and will bring widespread rain and higher elevation snow along with areas of strong, gusty winds. Overall, the forecast remains on track and have only made a couple adjustments. High resolution models and guidance show south winds gusting to 60 mph in the southern Shasta Valley this evening and tonight. So have upgraded the wind advisory (NPWMFR) to a high wind warning in the Shasta Valley. High wind warnings remain in effect for the coast and areas east of the Cascades and a wind advisory remains in place for portions of Jackson, Josephine and eastern Curry County.

Then, for snow expect snow levels to fluctuate tonight between 4000 and 5000 feet. This will bring some moderate snow to the mountains and some areas east of the Cascades. A winter weather advisory remains in effect for portions of the Cascades and mountains and higher passes in western/southern Siskiyou County. We have added a winter advisory for snow in northern/eastern Klamath and western Lake counties, this includes areas north of Chiloquin along Highway 97 and between Dairy and Lakeview along Highway 140. Snow may briefly change to rain or a rain/snow mix overnight as the front moves through, then expect additional snow showers Thursday morning. Shower activity decreases in intensity and coverage Thursday afternoon but then another strong and moist front arrives Thursday evening and night with additional snow. Gusty winds is also expected during the periods of snow and may create low visibilities at times. Travelers should be prepared for winter travel, take extra time when traveling or delay travel plans during the worst of the conditions. See the WSWMFR for additional details.

Additionally, moderate to heavy rain (around 1 to 3 inches) is expected tonight into early Thursday morning for areas along the coast and just inland across Coos, Curry, western Siskiyou, southwest Josephine and portions of Douglas County. There is expected to be a brief break with scatter showers late Thursday morning and afternoon, then another strong and moist front arrives Thursday evening and night with additional heavy rain and gusty winds. More fronts follow Friday into the weekend. This will create a potential for river and stream flooding, especially for areas along the coast but also inland into areas west of the Cascades. See the ESFMFR for details on the hydrologic outlook.

AVIATION...26/00Z TAFS

Mainly VFR weather early this evening over the MFR forecast area with terminals getting windier and precipitation enhancing on radar. Expecting conditions from the Cascades westward to become mountains obscured with MVFR ceilings and vsby in rain through daybreak. In addition, strong storm bringing increasing upper winds will pose wind shear threat to all terminals with south by southwest winds at 2kft AGL of 50-65kts. Wind shear abates west of the Cascades by 15z and thunderstorm threat develops in coast vcnty with ongoing MVFR conditions in widespread showers.

East of the Cascades including KLMT, windy from the south and LLWS will be prevalent through the night with areas of 3-5SM in light snow with MVFR cigs developing after 06z. Winds decrease late morning with ongoing MVFR prevalent in light snow showers through afternoon. Stavish

MARINE...Updated 200 PM PST Wednesday December 25, 2024

Winds continue to ramp up as the latest in a seemingly endless parade of fronts approaches this afternoon. We've already seen gusts over 50 KT in the northern waters, and seas remain extremely steep and chaotic. Widespread southerly storm force winds are expected by early evening which will continue into the night, and a storm warning remains in effect for all waters.

Pressure gradients peak overnight as the front moves through, after which winds will become more westerly and gradually ease. There will be a brief break with lower wind speeds tomorrow, but seas remain extremely high, steep, and hazardous. The next front brings south gales (at least) back to all areas tomorrow evening, and to avoid confusion and excessive headlines, the hazardous seas warning was dropped and replaced by a gale warning from tomorrow morning through Friday morning. Just understand that even though winds die down briefly tomorrow, it is not going to be safe out there. The combination of background swell and fresh swell will continue to produce large, chaotic seas, especially in the the surf zone and bars where breaking waves may reach 35 feet.

The parade of fronts looks to continue with one right after another every day and a half or so right on into the new year. -Wright

BEACH HAZARDS...Updated 200 PM PST Wednesday December 25, 2024

Seas will continue to build as the latest in a seemingly endless parade of fronts approaches this afternoon. This will result in continued extremely hazardous conditions on local beaches. Conditions will be particularly dangerous just behind the fronts as seas become west swell dominated and during the time of high tide - this occurs both tomorrow morning and behind another front Friday morning. Breaking waves may reach 35 feet both mornings. The high surf warning remains in effect through Friday.

During these events, extremely large breaking waves will create very hazardous and dangerous conditions along beaches and area shorelines. Waves will inundate beaches and surge into normally dry areas. Infrastructure damage and significant beach erosion can be expected. Stay away from area beaches during this period of active weather. -Wright

PREV DISCUSSION

/Issued 214 PM PST Wed Dec 25 2024/

DISCUSSION (Today through Tuesday)...

Overview:

Our active pattern continues across the forecast with impacts likely through this weekend and into early next week. Our next system is starting to move on shore today, and this will produce widespread impacts from the coast through the Cascades and over into the Eastside. Snow impacts will be mainly above 5000 feet, but there is a short window of snow levels around 4000 feet down around the Mount Shasta area and Marble Mountains early tonight. Snow levels will quickly start to rise late Friday morning. Wind speeds will be strong through Friday, so even light snowfall amounts could cause at least some visibility restrictions on top of hazardous road conditions. There will be another lull after this system, but another system will be quickly on the heels of this one, and we could see more wind, heavy rain, and snow impacts across the forecast area through this weekend. We will need to pay special attention to how rivers react to this system, so we can hopefully get a better gauge on potential river flooding expected this weekend. Please see the hydrologic outlook for further information.

Further Details:

Current H5 trough and associated surface low over the Gulf of Alaska are starting to impact the region early this afternoon with light precipitation moving through the area. Precip intensity will pick up this afternoon and will result in heavy rain (especially along and near the coast) tonight, higher elevation snow (mainly above 5000 feet), and wind impacts across the area. The biggest uncertainty is how low will snow levels drop because there is a short window of 4000 feet possible before precipitation really starts to ramp up tonight. This means some areas (mainly eastside) could see light snowfall amounts outside of the current advisory, especially areas above 5000 feet that are not in the advisory. Mount Ashland could see around 10-12 inches over 36 hours. Fairly decent probabilities (85%) for snowfall amounts 12.0" or greater in 24 hours for areas in and around Crater Lake. Probabilities decrease south towards Lake of the Woods for a foot or more of snowfall. Those areas around Lake of the Woods have a 10% chances of 12.0" or greater, but those probabilities increase to around 40% for 6.0" or greater in 24 hours for areas around the lake--all of which are a decrease from 24 hours ago for areas around Lake of the Woods. A combination of mixing and the pressure gradient will result in strong wind speeds near the coast and midslopes/higher elevation of the eastside where a High Wind Warning is in place. Gusts upwards of 70 mph will be possible in locations of the High Wind Warning. Strong winds will result in blowing snow and reduced visibilities during our snowfall windows, and we could have two distinctive periods of peak snowfall rate thanks to two different kicker lows coming out of the main cyclonic flow. The first peak would be around 4am-8am tomorrow morning when strong omega values exist within the dendritic growth zone with elevated CAPE noted, albeit only around 50-100 J/kg. The combination of instability and strong forcing could lead to snowfall rates around 1.5" per hour. There could be another peak Friday morning as well as another kicker wave comes out, but rates would only be around 0.5" per hour for the second peak. Again, wind speeds could create reduced visibilities, especially during high snowfall rates, but it doesn't take much snow to create visibility issues given the forecast wind gusts of 50-70 mph for some higher elevations.

There will be another storm system this weekend with more rounds of heavy rainfall, higher elevation snowfall, and wind hazards. This next system over the weekend could be closely on the heels of the current one, yet we could see much higher snow levels, so we will need to monitor river rises from heavy rain and snow melt through this weekend. After this week's parade of storm systems, we are seeing signs of potential flooding for some our of rivers and tributaries. A lot of uncertainty here with river forecasting. We will be taking a closer look at this over the coming days, especially after this system which could paint a clearer picture once we see how the rivers react.

-Guerrero

MFR WATCHES/WARNINGS/ADVISORIES

OR...Winter Weather Advisory until 10 AM PST Friday for ORZ027-028- 030.

High Wind Warning until 7 AM PST Thursday for ORZ021-022-030- 031.

High Surf Warning until 4 PM PST Friday for ORZ021-022.

Wind Advisory until 4 AM PST Thursday for ORZ024-026.

CA...Winter Weather Advisory until 10 AM PST Friday for CAZ080-082- 083.

High Wind Warning until 7 AM PST Thursday for CAZ081-085.

PACIFIC COASTAL WATERS...Storm Warning until 10 AM PST Thursday for PZZ350-356-370-376.

Gale Warning from 10 AM Thursday to 10 AM PST Friday for PZZ350- 356-370-376.