Plaincast
What the forecast actually says — NWS Area Forecast Discussions, decoded into plain English.
Revised in 16 passages since the 3:15 PM discussion. See every revision.
Moderate to heavy rain and strong gusty south winds across much of the area throughout Friday.
Very large surf Saturday with breaking waves over 25 feet is possible. This will increase beach erosion and possibly bring some coastal flooding.
Additional rain and wind possible over the weekend and into early next week.
A strong cold front passage will create gusty winds with moderate to heavy rain starting early Friday morning. Rain showers and thunderstorms are possible Friday afternoon. A brief break in the rain expected Saturday before another system with more rain and winds arrives Saturday night and Sunday morning.
A troughing pattern has set up over the Pacific Northwest, persisting through early next week. Two cutoff low pressure systems are projected to affect Northwest California as this pattern takes hold. The frontal boundary associated with the first cutoff low will begin to impact the region by late tonight causing strong southerly winds through mid-morning Friday along with widespread moderate to heavy rain tomorrow morning. The next frontal boundary with the next cutoff low will approach the area late Saturday and bring more southerly winds and moderate rain, but is anticipated to be weaker than the first.
With this first front, southerly winds have already been recorded with gusts between 30-50mph as of 12:30am. These winds are expected to increase, starting first at coastal headlands and higher elevations near the coast of Del Norte and Humboldt counties. Several high-resolution models show 55-65 knot winds aloft (at 925mb and 850mb) as the front moves into Humboldt and Del Norte counties. Lower levels of the atmosphere could be unstable enough this morning allowing these stronger winds to mix down to the lower elevations, especially along the coast where topographic friction is limited. The strongest winds are forecast for Del Norte County along with the King Range in Humboldt County. As this frontal boundary moves eastward, the higher elevations of Mendocino and Lake county are expected to have wind speeds between 40-50mph through the morning as well. Multiple warning and advisories have been issued for the forecast area through this morning.
In addition to the wind hazards, moderate to locally heavy precipitation is expected through the morning Friday. Friday afternoon after the initial frontal boundary passage, showers and even a few localized thunderstorms are expected into Saturday morning. and the potential for another bought of moderate rainfall on Sunday. Light rain has already begun in the King Range. The heavier, main band of rain is forecast 2 to 3 hours before sunrise or around ~4-5am this morning. The National Blend of Models (the blend-of-models forecast)indicates over an 85% chance of total rainfall amounts of 2 inches or more for Del Norte, most of Humboldt, northern and western Trinity, and northern Mendocino and over a 75 percent chance for 1.5 inches or greater during the same time period for central eastern Trinity, southern Mendocino, northwestern Lake counties with southeastern Lake most likely seeing close to an inch. The Humboldt Bay region has about a 65 to 75 percent chance of rainfall totals of 2 inches due to a rain shadow effect caused by southerly winds interacting with the King Range.
Behind the initial band of heavy rain, showers are expected, especially in Humboldt, Del Norte and northern Mendocino counties. The more heavy showers may bring close to an additional inch of rain with them. There is even the potential for some thunder with these showers as well due to increase atmospheric instability and colder air aloft entering the area. The the blend-of-models forecast thunder probabilities have come down slightly, but are still around 15 to 20 percent for the coast and 10-15% for inland areas.
Generally dry weather is expected on Saturday, although there may be some localized lingering showers or drizzle in the morning for mountainous areas. This calm period will be short-lived however as the next weather system moves in Saturday night into Sunday morning. This storm is expected to have lighter winds and rain, yet rainfall amounts of a half inch in Lake county to nearly two inches in the mountains of Humboldt and Del Norte counties is possible. Drier weather is possible Monday afternoon into Tuesday. Forecast ensembles continue to show a storm arriving mid week likely causing additional strong winds and rain for the area, yet details are limited and uncertain as of now. DS
This is the plain-text edition, decoded without AI so it loads anywhere. The full Plaincast experience — plain-English summaries beside the annotated original, with the forecast changelog — loads automatically with JavaScript, or open the interactive edition.
Data from the National Weather Service. Translated by Claude. About · For developers & agents · Subscribe: RSS feed for this office · Source on GitHub