“Cry me a(n) Atmospheric River” over Southwest California and the Baja

Meteorologists are still in amazement over the heavy rainfall event the beginning of the workweek.

From before sunrise Monday and for the next 24 hours, a very significant “atmospheric river” event brought heavy rain to the western 2/3rds of San Diego County, the Inland Empire, the Riverside County Mountains, and Coachella Valley. Heavy rain extended south of the border with flooding reported in Tijuana and as far south as Ensenada.

Rainfall in San Diego County approached 9 inches at Palomar Mountain, near 6 inches in the Mt. Laguna area, and ranged from 2 to 4 inches across much of the coast and inland valley areas. Riverside County saw totals to around 4 inches in the mountains, 2 to 3 inches Inland Empire. The Palm Springs area even saw rains around 1 inch, an uncommon event.

Down south into the Baja, rainfall amounts were likely in the 2 to 3 inch range.

See CNRFC graphic for US rainfall totals.


Rainfall totals from the Monday February 27 to Tuesday February 28 Rain event (From NOAA/NWS/CNRFC)

This is an example of an event researchers have termed an Atmospheric River. While the term is descriptive, it is overused by the media. Forecasters look for a persistent (more than 24 hours), wide, deep “ribbon” of high atmospheric moisture , especially at the lower levels of the atmosphere. This ribbon of moisture is pulled from the tropics by a approaching weather system and lifted, producing abundant widespread heavy precipitation.

This ribbon can be seen in computer weather forecasts. Shown below is the Global Ensemble Forecast System (GEFS) forecast for water vapor transport for later Monday morning into the afternoon, 2/27. The area in green outlined by red shows where large amounts of tropical moisture are being transported into southern California.


GEFS Model Output valid 1800 UTC (1000 PST) Monday, February 27

Unfortunately this event was not forecast by the computer models well in advance. While some similar events this winter in northern California were evident to forecasters 3 to 5 days (or more) in advance, this event only became evident about 12 hours before it occurred, and was more focused on far southern San Diego County and the Baja.

Jim Purpura CCM’s presentation at Wavelength Brewing Company


On Friday, January 6th, 2017 Jim Purpura CCM of WeatherExtreme Ltd. gave a presentation at the Wavelength Brewing Company in Vista CA. In his presentation, he discussed a new program in Malawai developed by the United Nations (UN) through the World Meteorological Organization (WMO) which aims to create a network of weather watchers who can share forecasts and warnings via cell phone. Below is photo and video from the event. In the video, he gives a brief demonstration of the current communication system being used for weather alerts.




Tornado near Sheridan California 1/9/2017

Monday’s storm system managed to generate a mini-supercell northeast of Sacramento, Ca. This is the first tornado of the year in California.
Fox 40 from Sacramento reported on it in this video…

The National Weather Service issued a storm report and called this a funnel cloud. But the rotating winds are clearly extending to the ground, making it a tornado.

The Base Reflectivity and Storm Relative Velocity are shown from 2:00 pm Monday, January 9. The Reflectivity shows hints of a supercell, including a rear flank downdraft wrapping into the storm. The Storm Relative Velocity at the same time indicates rotation in the updraft above the ground. These are signs to the warning forecaster the storm could produce a tornado.

Although a brief tornado was produced, there were no reports of any damage as this occurred in an open field.

Jim Purpura, CCM

Base Reflectivity of Tornadic Storm near Sheridan, CA
Storm Relative Velocity image of Tornadic Storm near Sheridan, CA

Jim Purpura of WeatherExtreme Ltd. is guest speaking at Wavelength Brewing Company January 6th.


Jim Purpura CCM, Meteorologist at WeatherExtreme Ltd., will be guest speaking at Wavelength Brewing Company on Friday January 6th at 8:00PM in Vista CA. He will be discussing a new program in Malawai developed by the United Nations (UN) through the World Meteorological Organization (WMO) which aims to create a network of weather watchers who can share forecasts and warnings via cell phone. . The project will merge two systems now being put in place across 9 nations in southern Africa: The Severe Weather Forecast Demonstration Project (SWFDP) and the Southern African Region Flash Flood Guidance (SARFFG) system.

For information on the upcoming event, click here to view the event on Facebook.

Snow falls in Sahara for First time in 37 years

The Algerian town of Ain Sefra, deep in the dry, hot Sahara desert was hit by a freak snowfall on December 19. It’s the first time snow has fallen in the region in 37 years. View the incredible photos of the town’s sand dunes capped with white snow:

Photo Credits: Karim Bouchetata