Storm battering California sets record low pressure mark

One of the most powerful low pressure systems since record keeping began in the 1800s slammed the West Coast yesterday with hurricane-force wind gusts, large hail, and torrential rains that have created flash floods and dangerous debris flows. The storm, centered just offshore near the Oregon/California border this morning, set an all-time record for the lowest pressure ever recorded along the southern Oregon coast yesterday. Medford, Oregon hit a pressure of 978 mb (28.88") yesterday afternoon, beating their old lowest ever pressure of 28.93" set in 1995. Northern California came close to setting a new record for lowest pressure as well, as Eureka, California hit 980 mb (28.93"), nearly matching the old record of 979 mb (28.91") set on Feb 22, 1891.


Figure 1. Huge waves up to fifteen feet high slam ashore yesterday on Agate Beach, in Northern California. Image credit: wunderphotographer Tsurai.

The storm, the latest and strongest of a series of El Niño-fueled storms to assault California this week, is expected to bring heavy rains of 1 - 3 inches over much of of the state today, wind gusts of up to 45 mph near the coast, and heavy snows of 1 - 2 feet to the Sierras. Arizona is expected to receive heavy rains of up to five inches from the storm. The storm will wind down by Friday, and California will have brief respite Saturday, before the next storm hits on Sunday and Monday. Sunday's storm should be much weaker, and the state will get a chance to dry out Wednesday and Thursday. However, another parade of storm is forecast to impact the state beginning on Friday the 29th, according to the latest long-range forecasts of the GFS and ECMWF models.

Severe weather in central California
The cold front associated with the strong low swept inland yesterday afternoon over central California, triggering heavy thunderstorms that brought hail and heavy rains in excess of two inches to some locations. A rare tornado warning was issued for Morgan Hill in the San Francisco Bay area at 2:02pm, when Doppler radar revealed a rotating thunderstorm. No touchdown of a tornado occurred, though 1-inch hail was observed in Morgan Hill. The Storm Prediction Center (SPC) has placed Los Angeles and San Diego in the "Slight Risk" region for severe weather today. The primary severe weather risk will be damaging thunderstorm winds, though a few tornadoes and waterspouts may also occur.

Snowfall amounts of 1 - 2 feet were recorded in the Sierra Mountains yesterday, with up to 4 1/2 feet of snow expected to fall by the time the storm ends on Saturday. Some precipitation amounts from the storm, for the 4-day period ending at 4am PST today:

Major Cities:

Los Angeles 2.80
San Francisco 3.49
Sacramento 2.35
Eureka 2.78
San Diego 1.65
Fresno 1.33

Sierra Nevada sites:

Chilkoot Meadow 7.08
Kaiser Point 6.60
Tenaya Lake 6.54
Graveyard Meadow 5.64
Tamarack Summit 5.36
Yosemite Village 4.04

Tornadoes, severe weather in the South
Tornadoes tore through Texas and Louisiana yesterday, with one twister destroying several homes and businesses near in Waskom, Texas, near the Louisiana border. Fourteen tornado reports were received yesterday by the Storm Prediction Center (SPC). SPC has placed portions of Alabama, Georgia, Mississippi, Tennessee, and Florida under their "Slight Risk" region for severe weather today. Already, there have been tornado warnings posted this morning for the Florida Panhandle, and southern Georgia.


Figure 2. Radar reflectivity from the Shreveport, LA radar last night shows the classic hook echo of the tornado that tore through Waskom, Texas.

Portlight successfully gets much-needed water filtration systems and medical supplies into Haiti
Portlight.org, the disaster-relief charity that has sprung up from the hard work and dedication of many members of the wunderground.com community, has successfully shipped medical equipment and a water filtration unit capable of supplying the needs of 3,500 people per day to the Dominican Republic, where was trucked to Haiti via road. These supplies have now made it to the earthquake zone, and have been targeted to go to those with disabilities, or who are living in areas where the main aid efforts have forgotten. Portlight is working through the local Catholic Church, which is probably best positioned to deliver private aid donations to those in need. Paul Timmons, leader of the Portlight relief efforts, wrote this to me yesterday:

Thanks to Wunderground blogger Dak Simonton (Dakster) we were made aware of Richard Lamarque, a Haitian expatriate and 15 year veteran of the Miami Police Department who was planning to go back to Haiti this week to look for family members and to help with recovery efforts. Our on scene coordinator, Richard Lamarque, will be leaving for Haiti in a few days. He is from there, is well connected there, and has a skill set and life experiences which will be invaluable to our work there.

We want this to be a uniquely Weather Underground community initiative. We will place WU signage on the truck...and we will be able to post photos of it at work in Haiti.

The Weather Underground community has been the genesis of our efforts. And the WU truck will be a long term, tangible symbol of the generosity of the WU community.



Figure 3. Walkers and medical supplies for Haiti getting ready to ship from the Portlight warehouse in Atlanta.

Thanks to the generosity of its donors, Portlight has been able to fund purchase of the truck for Richard Lamarque. Please visit the Portlight.org blog to learn more. Floodman's blog has the latest info on Portlight's plan for Haitian relief. The Reeve Foundation, founded by Christopher and Dana Reeve has awarded Portlight Strategies a $10,000 Quality of of Life grant to assist in the relief efforts in Haiti. This is very big and will allow Portlight to pursue more aggressive relief efforts over the course of the next few weeks.

For those of you more interested in helping out with the long-term rebuilding of Haiti's shattered infrastructure from the quake, I recommend a contribution to Lambi Fund of Haiti, a charity that is very active in promoting reforestation efforts, use of alternative fuels, and infrastructure improvements at a grass-roots level in Haiti. I've developed a great respect for the work they do in the country in the five years I've been a supporter.

Next post
My next post will be Friday.

Jeff Masters