Left: GEFS maximum observed coastal AR Scale analysis for the 7-day period ending 5 PM PDT 21 Mar 2026. Center: GEFS control AR Scale and IVT analyses for the 7-day period ending 5 PM PDT 21 Mar 2026 at 46.5°N, 124°W. Right: NWS Stage IV total estimated precipitation for the 6-day period ending 5 AM PDT 21 Mar 2026.

A long-duration #AtmosphericRiver produced moderate-to-heavy rainfall and flooding in portions of Washington last week.

See our latest Quick Summary for more details: cw3e.ucsd.edu/wp-content/u....

Page 1 of Quick Look. Summary of key forecast information.

Page 2 of Quick Look. Top: GFS 500-hPa geopotential height (contours) and 500-hPa geopotential height standardize anomaly (shading) forecasts valid at 5 AM PDT Fri 20 Mar (left) and 11 PM PDT Tue 24 Mar (right). Bottom: National Weather Service (NWS) experimental HeatRisk forecasts valid for Fri 20 Mar (left) and Wed 25 Mar (right).

Page 3 of Quick Look. Top: PRISM month-to-date (1-19 Mar) daily mean temperature anomalies. Middle: Basin snow water equivalent percent of 1991-2020 median valid on 1 Mar (left) and 19 Mar (right). Bottom: California-Nevada River Forecast Center (CNRFC) forecast peak runoff date for water year 2026 (left), average peak peak runoff date for 1991-2020 (center), and water year 2026 departure from average in days (right).

Page 4 of Quick Look. Top: West-WRF GFS integrated vapor transport (IVT; shading) and sea-level pressure (SLP, contours) forecasts valid at 11 PM PDT Sun 22 Mar (left) and 11 PM PDT Mon 23 Mar (right). Bottom: Comparison of IVT and SLP forecasts from West-WRF GFS (left) and West-WRF ECMWF (right) valid at 11 AM PDT Tue 24 Mar.

Unseasonably warm and dry conditions will persist over much of the southwestern US into next week, while another #AtmosphericRiver is forecast to impact the Pacific Northwest.

See our latest Quick Look for more details: cw3e.ucsd.edu/wp-content/u....

“While nobody resides in the newly declared evacuation zone, the district says the order is a precautionary measure to save lives, as the landslide is hazard is very high.” cheknews.ca/b-c-expands-... - @cheknews.ca

#AtmosphericRiver #BCFlood #BCStorm #OceanFalls

B.C. expands evacuation area due to flooding, risk of landslides A regional district on B.C.'s central coast has expanded a local state of emergency and evacuation orders because of flooding and the risk of landslides.

“An atmospheric river is currently drenching parts of B.C., and the Central Coast Regional District says the local state of emergency now covers the entire area that includes Ocean Falls.” cheknews.ca/b-c-expands-... - @cheknews.ca

#AtmosphericRiver #BCFlood #BCStorm #OceanFalls

It’s the #AtmosphericRiver of the drizzling shits in Metro Vancouver tonight.
Endless moderate drizzle soaking everything.
There’s a very sub-tropical feel to the weather tonight, too, very mild and humid.

Atmospheric river brings ‘tremendous’ amount of rain to B.C. South Coast - BC | Globalnews.ca 'We've seen some tremendous amounts of rain up on portions of the Central Coast, up in the river's inlet area,' Brian Proctor, a meteorologist with Environment Canada, said.

“An atmospheric river is now expected to stick around until Friday as heavy rain continues to soak B.C.’s South Coast.” globalnews.ca/news/1173664... - Global News

#AtmosphericRiver #BCStorm #FraserValley #HoweSound #VancouverIsland #YVR

A page with bulleted text describing the forecast atmospheric river over the Pacific Northwest and it's associated impacts in the coming days.

A page including figures that describe the progression of the AR using IVT maps and CW3E's AR Scale graphics describing the ensemble AR Scale forecasts associated with this event.

A page including CW3E's AR Landfall graphic highlighting the probability of AR conditions along the US West Coast and CW3E's QPF graphics highlighting 24-hour and 72-hour QPF forecast from the NWS WPC, with excessive rainfall outlooks overlaid on top.

A page including graphics from the NWS Northwest River Forecast Center highlighting locations forecast to experience flood conditions over the next 10 days. Also included are a median snowpack graphic and a forecast temperature map, highlighting the impacts of warm temperatures on the overall Western US snowpack.

A long-duration #AtmosphericRiver will continue to impact the Pacific Northwest through early Saturday, with flooding expected in western Washington. Check out our latest Quick Look for additional information or visit: cw3e.ucsd.edu/wp-content/u...

Original post on mastodon.social

“ by Bonny Matejowsky
Tue, March 17, 2026 at 2:31 PM : The National Weather Service announced an atmospheric river is bringing heavy to moderate rain across Western Washington this week.
Will Pierce County residents have to worry about a repeat of December’s pineapple express-fueled flooding? “ […]

Happily it looks like the #AtmosphericRiver that is aimed at Metro Vancouver isn’t as severe as initially forecast.
That said, be wary of pooling water on the roads.

A long-duration #AtmosphericRiver will bring moderate-to-heavy rainfall to portions of western Washington this week. Riverine flooding is possible due to the combination of snowmelt and rain at higher elevations.

See our latest AR Outlook for more information: cw3e.ucsd.edu/cw3e-ar-upda....

Tofino, BC - 7 Day Forecast - Environment Canada Current conditions and forecasts including 7 day outlook, daily high/low temperature, warnings, chance of precipitation, pressure, humidity/wind chill (when applicable) historical data, normals, record values and sunrise/sunset times

Orange Level Rainfall warning issued for West Coast Vancouver Island (#Tofino, #Ucluelet, #Bamfield, #Nitinat, #PortRenfrew)

weather.gc.ca/en/location/index.html

#BCStorm #AtmosphericRiver #Weather #VancouverIsland

youtu.be/2bxZC9qwCi4 #heatwave #pineappleexpress
#atmosphericriver

What makes it extraordinary? Other than it is still Winter?

Heat Wave Hits West Coast

Yikes. The forecast for the coming #AtmosphericRiver has worsened.
Up to 400 mm (40 cm) of rain for Torino, and close to 200 mm near my neck of the woods.
Beware of flooding and road washouts, especially in hilly areas.

DON’T DRIVE THROUGH FLOODED ROADS.

A radar image shows the island in green surrounded by blue water of the straights and green mainland. Overlayed is a semi transpararent light blue and green region that stretches north to south and covered the north central island in blue indicating snow and the ocean in green indicating rain

Mix of snow and rain begins on the Island. Atmospheric River event incoming. Look for ECCC to post various warnings today into tomorrow and through to Wednesday.
#bcstorm #bcsnow #portalberni #vancouverisland #atmosphericriver

Original post on socialbc.ca

Important: Special Weather Statement advising of a potentially serious spring-melt inducing Atmospheric River. West Vancover Island could see 300mm, Inland 150mm. Rivers could be dangerous due to snow melt.

The event will begin with potential snow Sunday shifting to heavy rain Monday through […]

Ensemble guidance is showing high confidence in a prolonged period of #AtmosphericRiver conditions over the PNW beginning this weekend and continuing through next week, with potential for heavy rain in WA from this event.

See our latest AR outlook for more details: cw3e.ucsd.edu/cw3e-ar-upda...

Page 1 of Quick Look. Summary of key forecast information.

Page 2 of Quick Look. Top Left: West-WRF integrated water vapor transport (IVT; shading), and sea-level pressure (SLP; contours) initialized 5 AM PT 11 Mar - F006. Top right: Same as top left but for F024. Bottom left: Same as top left but for F042. Bottom right: Same as top left but for F060.

Page 3 of Quick Look. (Top) GEFS ensemble probability of AR conditions [IVT≥250 kg/(ms)] along the West Coast of North America for the 16-day period valid 5 AM PT Wed 11 Mar through 5 AM PST Fri 27 Mar. (Bottom) CW3E 200-member West-WRF 7-day control and ensemble AR Scale and IVT forecasts for 46.5°N, 124°W (coastal southern Washington).

Page 4 of Quick Look. Top: NWS Weather Prediction Center (WPC) excessive rainfall outlooks (EROs) valid for the 24-hour periods ending 5 AM PT Thu 12 Jan, Fri 13 Jan, and Sat 14 Jan. Bottom left: WPC Total quantitative precipitation forecast (QPF) valid for the 7-day period ending 5 AM PT Sat 14 Mar. Bottom right: GEFS ensemble freezing level and WPC 6-hourly QPF forecasts in the Duwamish watershed for the 7-day period ending 11 PM PST Wed 18 Mar.

A long-duration #AtmosphericRiver is forecast to bring heavy rain and snow to portions of the Pacific Northwest this week with additional AR activity possible next week. See our latest Quick Look for more information: cw3e.ucsd.edu/wp-content/u...

Widespread Increase in Atmospheric River Frequency and Impacts Over the 20th Century Atmospheric river (AR) activity has increased broadly across the midlatitudes, rather than shifting polewards, since 1940 Increases in AR frequency enhance AR-associated precipitation and snowfal...

Read the #OpenAccess article for free over at
@wiley-stem.bsky.social!

🔗 doi.org/10.1029/2025...

#atmosphere #atmospherics #AtmosphericRiver

A low pressure system and an #AtmosphericRiver brought heavy precipitation to western Oregon and Northern California and snow over the Cascades and Bitterroot Ranges.

See our latest Quick Summary for more information: cw3e.ucsd.edu/wp-content/u....

North American Universities Support Global Expansion of Atmospheric River Science Program A program focused on key storm systems, known as atmospheric rivers, that provides students with hands-on research experience, launched its second season in January.

🌎 1️⃣ 6️⃣ teams represented by students from universities across North America are teaming up to collect observations to improve global #AtmosphericRiver forecasts. Learn more about the initiative led by @cw3escripps.bsky.social. ⤵️

Internal documents show B.C. considered buying landslide-risk properties that are now worthless, but didn't Internal documents show B.C. government explored helping homeowners stuck with landslide-risk properties deemed worthless

#UBCM #AtmosphericRiver #bcpoli #BCLocalGov #LocalGov

B.C. considered buying landslide-risk properties that are now worthless, but didn't -- vancouversun.com/news/bc-cons...

Page 1 of Quick Look. Summary of key forecast information.

Page 2 of Quick Look. Top left: West-WRF integrated water vapor (IWV; shading), sea-level pressure (SLP; contours), and 850-hPa wind (barbs) forecasts valid at 10 PM PST Mon 23 Feb. Top right: West-WRF integrated vapor transport (IVT; shading and vectors) and SLP (contours) forecasts valid at 4 PM PST Mon 23 Feb. Bottom left: West-WRF IWV (shading), SLP (contours), and 850-hPa wind (barbs) forecasts valid at 10 PM PST Tue 24 Feb. Bottom right: West-WRF IVT (shading and vectors) and SLP (contours) forecasts valid at 10 PM PST Tue 24 Feb.

Page 3 of Quick Look. Top left: West-WRF control maximum AR Scale forecasts along the coast for the 7-day period ending 4 PM PST Sun 1 Mar. Top right: West-WRF control and ensemble AR Scale and IVT forecasts at 41°N, 124°W (Humboldt County) valid for the same time period. Bottom left: NWS Weather Prediction Center (WPC) Day 1 quantitative precipitation forecast (QPF) and excessive rainfall outlook (ERO) for the 24-hour period ending 4 AM PST Tue 24 Feb. Bottom center: NWS WPC Day 2 QPF and ERO for the 24-hour period ending 4 AM PST Wed 25 Feb. Bottom right: NWS WPC total QPF for the 48-hour period ending 4 AM PST Wed 25 Feb.

Page 4 of Quick Look. Top left: Map showing the percent of total 7-day precipitation forecast to fall as rain and/or snow (shading) in different watersheds based on forecasts from the GEFS ensemble. Top right: GEFS 7-day ensemble freezing level forecasts (lines) and WPC 6-hourly mean areal QPF (bars) for the Upper Yuba watershed. Bottom left: 10-day river stage forecasts issued by the Northwest River Forecast Center (NWRFC). Bottom right: 5-day river stage forecasts issued by the California-Nevada River Forecast Center (CNRFC).

A strong #AtmosphericRiver fueled by tropical and subtropical moisture will bring heavy rain to portions of the Pacific Northwest and California today and tomorrow.

See our latest Quick Look for more information: cw3e.ucsd.edu/wp-content/u....

Following a whiplash transition from record warmth to very heavy mountain snowfall in California, yet another swing back toward anomalous warmth (first damp, then dry) - Weather West A remarkable snowy interlude during what has thus far been a record warm winter: Disruptive, and even deadly, in the Sierra Nevada Last week's snowfall in the Sierra Nevada--and also at much lower elevations, for the first time this season, into even the lower foothills and Coast Ranges--marked a dramatic shift from a nearly 40-day

New on Weather West: If we're going to see an extremely moist & warm #AtmosphericRiver this wk in NorCal that will bring rain atop recent heavy snow, why is major flooding *not* expected? It a story of (lacking) storm dynamics & snowpack resilience. #CAwx

CW3E AR Update: Confidence has increased in a long duration #AtmosphericRiver event associated with a slow-moving low-pressure system, forecast to bring heavy precip to the U.S. West Coast between Sat 21 and Wed 25 Feb.

See our latest outlook for more information: cw3e.ucsd.edu/cw3e-ar-upda...

After the #atmosphericRiver, rain droplets on the pink jasmine…

CW3E AR Update: #AtmosphericRiver conditions associated with a slow-moving low-pressure system are forecast to bring precipitation to the U.S. West Coast between Sat 21 and Thu 26 Feb.

See our latest outlook for more information: cw3e.ucsd.edu/cw3e-ar-upda....

Well, a delightful 5 minutes of hail at lunch time.
#hail
#sonoma
#atmosphericriver

Empty buildings under construction on a stormy, cloudy day

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#sf #streetphotography #rain #storm #atmosphericriver #california #city #urbangaze #architecture #palmtree #vacant

Page 1 of Quick Look. Summary of key forecast information.

Page 2 of Quick Look. Top left: West-WRF 500-hPa geopotential height (contours), absolute vorticity (shading), and wind (barbs) forecasts valid at 4 PM PST Tue 17 Feb. Top right: West-WRF integrated vapor transport (IVT; shading and vectors) and sea-level pressure (SLP; contours) forecasts valid at 4 PM PST Tue 17 Feb. Middle left: West-WRF 500-hPa geopotential height (contours), absolute vorticity (shading), and wind (barbs) forecasts valid at 1 AM PST Thu 19 Feb. Middle right: West-WRF IVT (shading and vectors) and SLP (contours) forecasts valid at 1 AM PST Thu 19 Feb. Bottom: West-WRF simulated reflectivity (shading), and SLP (contours) forecasts valid at 1 AM PST Wed 18 Feb (left) and 12 PM PST Thu 19 Feb (right).

Page 3 of Quick Look. Top: West-WRF 7-day control and ensemble AR Scale and IVT forecasts for 34°N, 118.5°W (Los Angeles County). Bottom left: NWS Weather Prediction Center (WPC) Day 1 quantitative precipitation forecast (QPF) and excessive rainfall outlook (ERO) for the 24-hour period ending 4 AM PST Wed 18 Feb. Bottom right: NWS WPC total QPF for the 72-hour period ending 4 AM PST Fri 20 Feb.

Page 4 of Quick Look. Top left: NWS total snowfall accumulation forecast for the 72-hour period ending 4 AM PST Fri 20 Feb. Top right: NWS WPC Winter Storm Severity Index for the 72-hour period ending 4 AM PST Fri 20 Feb. Bottom: West-WRF ensemble probability of AR conditions [IVT≥250 kg/(ms)] and control member maximum AR Scale forecast along the West Coast of North America for the 7-day period valid 4 PM PST Mon 16 Feb through 4 PM PST Mon 23 Feb.

Multiple winter storms and a weak #AtmosphericRiver will bring additional rain and heavy snow to California this week. There is potential for another impactful AR this weekend into early next week.

See our latest Quick Look for more information: cw3e.ucsd.edu/wp-content/u....