CW3E Scripps

A introductory slide showing the title of this article and Figure 14 from Gibson et al. 2026

CW3E Publication Notice: "Emerging trends in landfalling atmospheric rivers over the South Pacific" was recently published in npj Climate and Atmospheric Science.

Visit our website to read more about this research: cw3e.ucsd.edu/cw3e-publica...

A cover slide including the title of the article and the graphics for Figure 2 from Zou et al. (2026), Frontiers in Earth Science.

CW3E Publication Notice: "Antarctica’s uncertain future: sea-level rise from oceanic and atmospheric forcing, with a focus on atmospheric rivers" in Frontiers in Earth Science.

To read more about this research visit: cw3e.ucsd.edu/cw3e-publica...

CW3E Publication Notice: Several papers investigating the impacts of #AtmosphericRivers on cloud radiative effects in both the Arctic and Antarctic have recently been published.

Read more about these publications here: cw3e.ucsd.edu/cw3e-publica...

CW3E Publication Notice: "Antecedent moisture enhances early warning of atmospheric river flood hazards" in Nature Communications.
Read more about this research here: cw3e.ucsd.edu/cw3e-publica...

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. ⤵️

Left: Total estimated precipitation for the 5-day period ending 4 AM PST Fri 20 Feb based on the National Weather Service (NWS) Stage IV product. Center: Total estimated snowfall for the same period based on the NWS National Operational Hydrologic Remote Sensing Center (NOHRSC) snowfall analysis product. Right: NWS local storm reports received during the same period, color-coded by category.

Multiple winter storms brought heavy rain and snow to California last week. Portions of the Sierra Nevada received more than 6 feet of total snow.

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

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....

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...

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....

Observations of stream level and concurrent image classifications from field camera photos at Perry Creek from August 2017 to September 2019. Four example field camera images are shown. Field camera images were not available in 2019. From Figure 9 in Ogle et al. (2026).

CW3E Publication Notice: "Image-based classification of stream stage to support ephemeral stream monitoring" in @egu.eu's Hydrology and Earth System Sciences.

For a summary of this paper, visit: cw3e.ucsd.edu/cw3e-publica....

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....

The 2026 International Atmospheric River Conference (𝗜𝗔𝗥𝗖𝟮𝟬𝟮𝟲) is coming to Porto, Portugal!

📅 19–23 October 2026 | 📍 Alfândega Congress Centre + virtual option

Join the conversation on atmospheric rivers and their impact on water, weather extremes, and climate resilience.

Structural Similarity Index (SSIM, top) and Continuous Ranked Probability Score (CRPS, bottom) as a function of lead time for 3D U-Net model (blue) and 3D U-Net Diffusion (red), ConvLSTM (green), and Optical Flow (yellow) with 95% confidence intervals from 1000 bootstrapping. Figure 4 from Afzali Gorooh et al. (2026).

CW3E Publication Notice: "Deterministic nowcasting of geostationary satellite infrared brightness temperature using a 3D U-Net diffusion model" in @nature.com's Scientific Reports.

For a summary of this paper, visit: cw3e.ucsd.edu/cw3e-publica....

Performance metrics of 6-hourly WRF FZL, linear regression, and U-Net postprocessing (U-Net-RMSE, U-Net-GMM, and U-Net-log) forecasts during December 2016–March 2017 over the Yuba–Feather watershed: (a) Pearson’s correlation coefficient and (b) RMSE vs CNRFC observations as a function of lead time (hours). Figure 4 from Afzali Gorooh et al. (2026).

CW3E Publication Notice: "Enhancing Deterministic Freezing-Level Predictions in the Northern Sierra Nevada through Deep Neural Networks" in @ametsoc.org's Journal of Hydrometeorology.

For a summary of this paper, visit: cw3e.ucsd.edu/cw3e-publica....

Accumulated (a)–(c) total, (d)–(f) stratiform, and (g)–(i) convective precipitation during 12–15 Feb 2019 according to ERA5 (left) and WRF simulations groups using Tiedtke (center) and Grell–Freitas (right) convective schemes. Note the change in color bar between total/stratiform and convective precipitation. Figure 6 from Luna-Niño et al. (2026).

CW3E Publication Notice: "Convection Embedded in an Atmospheric River: Exploring Precipitation Sensitivity to Convective Parameterizations" in @ametsoc.org's Monthly Weather Review.

For a summary of this paper, visit: cw3e.ucsd.edu/cw3e-publica....

CW3E Winter Storm Update: Multiple winter storms are forecast to bring rain and heavy snow to California late this weekend into much of next week.

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

Page one of the quick look featuring forecast highlights.

Page two of the quick look. On top are West-WRF based on the GFS 500-hPa heights showing the progression of the troughs. On bottom are forecast comparisons between the West-WRF based on the GFS and ECMWF.

Page three of the quick look. On top is West-WRF AR Scale matrix showing low probability of AR conditions next week. On the bottom is watershed precipitation forecast for the Upper Yuba watershed in the next 10 days.

Page four of the quick look. On top is a forecast comparison between the West-WRF based on the GFS (left) and ECMWF (right) for the second trough. On bottom is EPS probability of 24+ in. of snow on the right (from Weather Bell) and on the right is GEFS freezing level forecast for the Upper Tuolumne watershed.

CW3E AR Update: There is an indication for a pair of mid-level troughs and surface low pressure systems are forecast to bring precipitation to much of California beginning this weekend and continuing through the end of next week.

Read the full Quick Look here: cw3e.ucsd.edu/wp-content/u...

CW3E is hiring a Project Scientist to join our team and work on topics related to subseasonal-and-seasonal (S&S) prediction! We are seeking a well-rounded hydroclimate scientist able to contribute to and evolve several projects. Read the job posting and apply here: apol-recruit.ucsd.edu/JPF04422

CW3E AR Update: Here is a quick look at the weak atmospheric river forecast to move over California on Tuesday and bring primarily beneficial rain and snow to the state through mid-week. Read the full Quick Look here: cw3e.ucsd.edu/wp-content/u...

Page one of the quick look featuring forecast highlights.

Page two of the quick look. On top are select GFS IVT forecasts showing the propagation of the AR this weekend. In the middle is a comparison between the GFS and EC IVT late in the event. On the bottom is a comparison between the EPS and GEFS AR Scale for a point in the central Oregon coast.

Page three of the quick look. On top is WPC 72-hour forecast precipitation on the left and the marginal excessive rainfall outlook issued over the Olympic Peninsula on the right. On bottom are freezing level forecasts watersheds in the Washington and Oregon Cascades.

Page four of the quick look. Shown are NWRFC streamflow forecasts across western Washington.

CW3E AR Update: An #AtmosphericRiver is forecast to bring moderate precipitation to the Pacific Northwest this weekend into early next week.

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

How dry? In fact, San Francisco International Airport will be dry for 31 straight days if there is no rain between today and the big game. This would only be the 9th winter since 1945-1946 in which San Francisco has recorded at least 30 consecutive dry days during the months of Dec, Jan and Feb.

The forecast for Super Bowl Sunday near Levi's Stadium is mostly dry and warm, with a slight chance of light rain in the evening. Normally, December, January and February are the three wettest months of the year in northern California, but it has been unusually dry since early January.

Left: GEFS maximum observed coastal AR Scale for the 7-day period ending 4 PM PST 1 Feb 2026. Center: GEFS control AR Scale and IVT analyses for the 7-day period ending 4 PM PST 1 Feb 2026 at 47.5°N, 124.5°W. Right: NWS Stage IV total estimated precipitation for the 6-day period ending 4 AM PST 2 Feb 2026.

A family of #AtmosphericRivers brought moderate-to-heavy precipitation to portions of Washington last week.

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

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

Page 2 of Quick Look. GFS integrated vapor transport (IVT; shading and vectors) and sea-level pressure (SLP; contours) forecasts valid at 10 AM PST Tue 27 Jan (top left), 10 AM PST Wed 28 Jan (top right), 4 PM PST Thu 29 Jan (bottom left), and 4 PM PST Sat 31 Jan (bottom right).

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 4 AM PST Mon 26 Jan through 4 AM PST Wed 11 Feb. (Bottom) GEFS 7-day control and ensemble AR Scale and IVT forecasts for 47°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 4 AM PST Thu 29 Jan, Fri 30 Jan, and Sat 31 Jan. Bottom left: WPC Total quantitative precipitation forecast (QPF) valid for the 7-day period ending 4 AM PST Mon 2 Feb. Bottom right: GEFS ensemble freezing level and WPC 6-hourly QPF forecasts in the Duwamish watershed for the 7-day period ending 4 AM PST Mon 2 Feb.

CW3E AR Update: Multiple #AtmosphericRivers are forecast to bring heavy precipitation to portions of the Pacific Northwest this week.

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

CW3E has prepared a detailed event summary discussing the multiple #AtmosphericRivers that produced heavy precipitation, significant snowfall, and widespread impacts over the US West Coast between 18–27 Dec 2025. Read our extensive analysis here: cw3e.ucsd.edu/cw3e-event-s...

We posted a quick summary of the #AtmosphericRivers that influenced precipitation across the US West Coast and led to heavy precipitation in CA this past week. Check out more here: cw3e.ucsd.edu/wp-content/u...

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

Page 2 of Quick Look. Top left: GFS integrated vapor transport (IVT; shading and vectors) and sea-level pressure (SLP; contours) forecasts valid at 10 AM PST Tue 6 Jan. Top right: GFS freezing level (shading), SLP (contours), and 10-meter wind (barbs) forecasts valid at 10 AM PST Tue 6 Jan. Bottom left: GFS IVT (shading and vectors) and SLP (contours) forecasts valid at 7 AM PST Wed 7 Jan. Bottom right: GFS 500-hPa geopotential height (contours), absolute vorticity (shading), and wind (barbs) forecasts valid at 7 AM PST Wed 7 Jan.

Page 3 of Quick Look. Top: GEFS 7-day freezing level forecasts and 6-hourly WPC precipitation forecasts for the Skykomish watershed. Color shading denotes portion of precipitation forecast to fall as rain, snow, or uncertain precipitation type. Bottom left: NWS Weather Prediction Center (WPC) quantitative precipitation forecast (QPF) valid for the 72-hour period ending 4 AM PST Fri 9 Jan. Bottom right: NWS snowfall accumulation forecast for the 72-hour period ending 4 AM PST Thu 8 Jan.

Page 4 of Quick Look. Top left: West-WRF ensemble cumulative snowfall forecasts at Snoqualmie Pass for the 7-day period ending 4 PM PST Sun 11 Jan. Top right: NWS Weather Prediction Center (WPC) Winter Storm Severity Index valid through 7 AM PST Thu 8 Jan. Bottom: NRCS basin (HUC6 boundaries) and station (dots) snow water equivalent (SWE) expressed as a percent of the 1991-2020 median as of 5 Jan.

Multiple systems are forecast to bring low-elevation rain and heavy mountain snow to the Pacific Northwest this week.

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

Check out our latest AR Quick Look discussing the #AtmosphericRiver forecast to make landfall later today and bring precipitation impacts to California into early next week. Read more here: cw3e.ucsd.edu/wp-content/u...

A pair of #AtmosphericRivers and a low-pressure system drive precipitation across California over the next week, including potentially significant snowfall over the Sierra Nevada during the second AR.

See the latest AR outlook for further details: cw3e.ucsd.edu/cw3e-ar-upda...