Strong winds, snow and rain from a large atmospheric river to the west coast

On November 19, 2024By Littum

A large atmospheric river will hit the West Coast, from Washington to California, by midweek. Forecasts show a large influx of moisture arriving Tuesday night and lingering through the end of the week, possibly into the weekend.

SEATTLE – A powerful one bomb cyclone associated with a major atmospheric river is expected to drench the West Coast, from Washington to California, this week and potentially lead to life-threatening flooding and blizzard conditions.

The term “bomb cyclone” comes from the meteorological term “bombogenesis” or “explosive cyclogenesis”. This happens when a storm system’s central pressure drops by at least 24 millibars within 24 hours.

This storm could be of historic strength. According to NWS Seattle, the lowest pressure recorded off Washington was on October 24, 2021 at 942 mb (27.81 in). Model forecasts indicate the storm will approach this pressure level Tuesday night, according to the FOX Weather Center.

WHAT IS A ‘BOMB CYCLONE’?

A three-hour radar loop showing where showers and thunderstorms are underway. Severe thunderstorm warnings are indicated in yellow. Tornado warnings are indicated in red, while tornado warnings with a confirmed tornado are indicated in purple. Flood warnings are indicated in green, while emergency flooding is indicated in pink.
(FOX Weather)

‘High risk’ flood threat for Northern California

A large influx of moisture is set to arrive Tuesday night and stick around for the end of the week, possibly into the weekend, according to the FOX Forecast Center.

The system will bring steady, moderate rain for several days. This will likely lead to flooded roads, streams and even larger rivers.

HOW TO SEE FOX WEATHER

Forecasts show a large influx of moisture arriving Tuesday night and lingering through the end of the week, possibly into the weekend.

(FOX Weather)

Northern California will be the outer eye of this atmospheric river. From Wednesday through Friday, some areas could see 2-4 inches of rain daily, with even higher amounts possible in the mountains.

This has prompted the Weather Prediction Center to issue a rare “high risk” flood area for Northern California on Thursday.

WHY RARE “HIGH RISK” FLOOD DAYS SHOULD BE TAKEN SERIOUSLY

Daily rainfall amounts of 2-4 inches are expected over several days.

(FOX Weather)

80 mph winds possible

Strong winds will also begin to blow Tuesday night as the storm moves in. Gusts of 60-70 mph are expected in exposed areas such as ridges, headlands and parts of the coastal plains, the FOX Forecast Center said. The worst winds will develop Tuesday night and taper off Wednesday.

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Strong winds will also kick in Tuesday evening as the storm moves in.

(FOX Weather)

Snowstorm in the mountains

In the Cascades, winds will combine with heavy snow to create dangerous blizzards. Travel is expected to become impossible Tuesday night into Wednesday morning. Like most atmospheric rivers, this one will dump feet of snow in the Cascades and Sierra Nevada. But the warmer Pacific air drawn in by high winds will raise snow levels higher than normal.

Blizzard warnings have been issued for all of the Cascades from late Tuesday afternoon through Wednesday morning. This is where high winds are most likely to overlap with snow and reduce visibility to a quarter mile or less for at least three consecutive hours.

WHAT IS A BLIZZARD?

This atmospheric river will dump feet of snow in the Cascades and Sierra Nevada.

(FOX Weather)

Snow will likely begin around 3,500 feet, with the heaviest amounts above 4,000 feet, covering mountain ranges with several feet of snow.