textproduct: Medford

DISCUSSION

A shortwave trough passing to the north of the CWA is helping to lower temperatures. The Umpqua, Rogue, and Illinois valleys will see some cooler daytime temperatures today as that shortwave trough starts to flatten an upper ridge. A cooling trend continues into Monday, when all areas should approach seasonal norms. Coastal areas and east side valleys look to be in the mid to high 40s while west side valleys will generally be in the low 60s. Similar temperatures continue into Tuesday. A slight shift to a more southwest flow aloft could bring enough moisture to allow for light showers east of the Cascades into early Wednesday morning. Snow levels in this timeframe are high enough that only areas peaks and ridgelines should see light snow showers. Overall, the start of the week is somewhat uneventful.

A low pressure system looks to drop down from the Gulf of Alaska and move over the area through Wednesday and Thursday. Widespread rainfall is expected, with coastal cities forecast to see 1.5 to 25 inches of rainfall through these two days. Coastal ranges could see up to 3 inches of rainfall. The Illinois and Umpqua valleys could exceed an inch of rain, while other west side valleys look to remain between 0.5 and 1 inch overall. Areas east of the Cascades may see some light rainfall on Wednesday morning and afternoon. With an absence of existing snowpack, river flooding is not a concern. Local small stream or urban flooding may be possible, especially in areas with poor drainage.

Snow levels look to drop through Wednesday and Thursday, making mountain snowfall a concern through this period. Snow levels drop to 5500-6000 feet by Wednesday evening, which would keep snow to higher terrain in western Siskiyou County and along the Cascades. The highest Cascades passes may start to see snow snowfall in this timeframe. Snow levels are forecast to reach 5000 feet by Wednesday night and 2500-3000 feet by Thursday afternoon. That Wednesday evening period is concerning, as continuing moderate to heavy precipitation could bring snowfall rates of 1 inch per hour over Cascades passes. Those lower snow levels on Thursday will support continuing snowfall over the Cascades as well as light snowfall over some I-5 passes. Current forecasts have 1 inch or less of snowfall over Siskiyou Pass and between Weed and Dunsmuir, with 1 to 2 inches of snowfall around Snowman Summit on Highway 89. Snowfall east of the Cascades would generally be limited to Thursday morning and easing into the afternoon. Areas between Crescent and Chemult could see 3 to 6 inches of snowfall. East side valleys and basins are forecast to see 1 to 3 inches of snowfall, with 6 to 12 inches possible over Bly Mountain and the Warner Mountains.

Gusty winds are also expected over area terrain, especially east of the Cascades. Southerly winds will flow into the Shasta Valley, with current forecasting approaching but just short of Advisory speeds. Winds east of the Cascades look more likely to reach Advisory criteria, with gusts over Winter Rim and the Warner Mountains having a 70-90% chance to exceed 40 mph per NBM probabilistic guidance.

Please stay tuned to upcoming forecasts, as this system is currently just outside of high-res data availability. While some combination of Winter and Wind products look possible, that high-res information will help to fine-turn the timing and expected conditions.

A broad picture is present for the long-term forecast, but the details are coarse. Behind the low pressure system, Thursday night looks to have the coldest temperatures of the forecast period. An upper ridge looks to build in the wake of the low pressure system, bringing warmer temperatures and dry conditions to end the week and into the weekend. Long-term meteogram guidance shows activity is possible into next week, but the timing and pattern is scattered in associated imagery. -TAD

AVIATION...29/18Z TAFs

Marine stratus is burning off in the next hour or so, and there will be VFR with low VFR ceilings possible as light showers move in this afternoon. Northwest winds will pick up across the area today, with gusts of 20-30 kt possible this afternoon. The shower activity will come to west side valleys later this evening and into the overnight hours. -Hermansen

MARINE...Updated 200 PM PDT Sunday, March 29, 2026

Steep building seas and stronger north winds will continue through Monday night. This includes a possibility of gale force gusts in the outer waters south of Cape Blanco.

Brief improvement is likely on Tuesday ahead of a strong cold front. Active weather Tuesday evening into Wednesday is forecast to bring rain with building south to southwest winds likely reaching gale force, and seas possibly becoming very steep. The outlook is for steep to very steep seas to build to a peak on Thursday, but also persist late next week.

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Tuesday for PZZ356-376.

Small Craft Advisory from 8 PM this evening to 5 AM PDT Tuesday for PZZ350-370.