Marine Weather and Tide Forecast for Etna, CA

FXUS66 KMFR 222154 AFDMFR

Area Forecast Discussion National Weather Service Medford OR 254 PM PDT Tue Apr 22 2025

DISCUSSION
Northwest flow aloft continues to support seasonable temperatures and uneventful conditions across northern California and southern Oregon this afternoon. A weak upper trough will pass over the area this evening and through the day Wednesday. Winds may be a little breezier than normal this evening, but nothing remotely hazardous is expected. There will be some moderate shower chances (20-40%) across Modoc, eastern Siskiyou, and southern Lake counties through the day Wednesday. Any showers that do form will be isolated or scattered. Rainfall will be measured in the hundreths of an inch, if it even reaches the ground. Instability will be weak, with periods of 200-300 J/Kg at most on Wednesday evening. Lightning is not widely expected, but a stray strike or two is not impossible.

Conditions calm through the day Thursday as the pattern changes with an approaching upper level low pressure system. Southerly flow aloft along the leading edge of the system will allow for initial slight precipitation chances (15-30%) over the Siskiyou ranges and the Cascades on Thursday afternoon. Cooler daytime temperatures are forecast for Friday and continue through the weekend. With the low expected to pass to the south, gusty winds are not a concern through the weekend.

Widespread precipitation chances (40-80%) are forecast for Friday as the low passes to the south. Southerly flow aloft on Friday will bring more showers to areas west of and along the Cascades as well as northern Klamath and Lake counties. Higher terrain could see between 0.5 to 1.0 inches of rainfall, with 0.3 inches or less of rainfall for lower elevation areas. Snow levels of 5000 feet west of the Cascades will allow for 2-4 inches of snowfall over southwestern Siskiyou County peaks and ridgelines. Snow levels of 5500-6500 feet along and east of the Cascades will keep unremarkable snowfall to the highest terrain. Rainfall over Modoc and southern Lake and Klamath counties will generally be 0.1 inches or less.

40-80% precipitation chances continue across the area on Saturday, but flow aloft will be more easterly as the low passes over California. This will bring higher precipitation amounts to Lake and Modoc counties. Amounts are still unimpactful, with one-fourth of an inch or less of rainfall forecast for east side basins. Snow levels along and east of the Cascades will drop slightly to 5000-6000 feet, allowing for 4-8 inches of snowfall over Warner Mountain peaks through the day. Bly Mountain and the Cascades may see 2-4 inches of snowfall at the highest elevations. These amounts are not near product thresholds, but extra caution traveling through these areas on Saturday would not hurt. Rainfall over west side valleys will generally be 0.1 inches or less.

Activity starts to decrease late Saturday night, with any Sunday showers limited to the Cascades and easternmost Lake and Modoc counties. High pressure over the Pacific Ocean will bring generally drier conditions and seasonal temperatures through next week.
Meteogram guidance for both the ECMWF and GFS show occasional weak and brief precipitation signals, as well as wide ranges in daytime highs across ensemble members. How the high develops will be important for resulting conditions next week, but impactful or hazardous conditions currently look unlikely in the long-term.
-TAD
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