How Much Rain Is Needed to End the California Drought? 

How Much Rain Do We Need to End the California Drought? 

 

First, drought, like beauty, is in the eye of the beholder. Each different user group has their own metric for how much is enough for them to breathe easier.  For some activities just a normal rainfall year in their local area might be enough, while much of the state needs at least 150% of normal and some users may need on the order of 200% of normal.  Of course all of these solutions are complicated by California’s complex water delivery system which means that where the rainfall is measured is not necessarily where it is used! [The Drought Monitor and Drought Termination and Amelioration pages give some insight, though both are biased by factors related to agricultural drought.]

A simplistic way to look at the water shortage in California is to look at the rainfall deficits around the state from the past four seasons, and then add in the current rainfall season. In doing so (see table below) the deficits range from almost two times normal to about three-and a half time normal.

Or to look at it another way, all but Salinas would need an all-time record rainfall year to erase the 5-year deficit.



Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

 

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Seasonal Rainfall Page

Seasonal Rainfall Page

 

I have begun producing an (almost) daily update of California Rainfall Summary, based on the long-established rainfall season of July 1st to June 30th. The data is based on the raw summary put out by the CNRFC, which unfortunately and unexplicitly changed to the October 1st water year (WY), but with the more climatologically sound July to September period added in. An example of the product is below, and the link to the actual daily summary is:  http://ggweather.com/seasonal_rain.htm

Also included on the page is a link to the Excel spreadsheet (with instructions) that you can use to create the seasonal summary yourself if I am unable and/or you are impatient. Enjoy!


Questions and comments welcome.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com
 

 

 

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Why This Isn't Really the First El Niño Storm of the Season

Why This Isn't Really the First El Niño Storm of the Season

 

Many headlines in recent days have been touting the current and upcoming rain as the first El Niño storm(s) of the year.  In reality, every weather system we have seen in California, and elsewhere, have been influenced by El Niño; going back to its strengthening in the eastern tropical Pacific last fall. And every storm will continue to have to some "El Niño DNA" in them, well into spring.

The pattern that we saw in December, with a series of colder storms from the Gulf of Alaska, were not as characteristic of El Niño, but they were certainly related as distant cousins.

The current pattern, with a series of storms moving almost directly west to east (i.e., zonal flow) across the Pacific in the middle latitudes, is what is more commonly thought of as a "typical" El Niño pattern.



This pattern is more closely related to the impact of El Niño on the jetstream pattern in the Pacific; and to extend the familial metaphor are more like brothers and sisters.  This is very reminiscent to what we saw in January through March of 1998.  It should be noted that during those months in 1998 that while there were lots of rainy days, most of the daily amounts were in the moderate category and not heavy rain days.

Jan Null, CCM
Golden Gate Weather Services

 

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December California Summary and Wet Weather Forecast Tools

December Summary and Forecast Tools

 

The December California Summary was highlighted by some stark contrasts in rainfall around the state while temperatures were pretty close to normal. In the SF Bay Area, downtown San Francisco rainfall was 14% above normal while San Jose was 15% below normal. (So the average of the two would be normal?)  Elsewhere north of the Tehachapis, rainfall was generally well above normal, with 180% of normal at Eureka, 168% at Fresno and 131% at Redding; but Sacramento was the outlier with only 50%of normal. 
 


I have put together a simple map interface to access the "sampled" GFS for locations around California. See http://ggweather.com/gfs.htm.  

While the GFS is not always the best model,especially out past about 5 days, the sampled data gives a good quick "first guess".  For example the "Total Precip" column is an easy way to see the timing of an approaching system. And if any of the values on the page are underlined, you can click through to see the associated charts. Previous QPF amounts can also be compared at http://wxweb.meteostar.com/sample/compare_qpf.shtml?text=KOAK.
 


The QPF page has been updated and hopefully all the links are working. Lots of rainfall and river resources to be aware of and hopefully used often in the coming months.
 



Happy New Year.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com 

Posted

Northern California Mid-Winter Dry Spells

Northern California Mid-Winter Dry Spells

 

On almost as regular basis as the swallows returning to San Juan Capistrano an extended period of dry weather likes to return to Northern and Central California in the middle of winter.

Based on San Francisco's daily rainfall, over the past 65 rainfall seasons (i.e., July 1 to June 30) there has been a "dry" period in December or January averaging 20 days. For practical purposes a "dry period" is defined here as consecutive dry days with no rain, or consecutive days broken by no more than two non-consecutive intervening days of very light (* i.e., ≤ 0.08 inches) rain].  The average dry period during seasons with an El Niño was 17 days, while the average rose to 19 days during "ENSO neutral" years and 21 days during La Niña.

The shortest dry spell was 8 days which occurred twice, in 1957-58 and again in 1994-95.  Both of these seasons were during El Niño events.  The longest dry spell was 56 days in 2014-2015, when there was 18.19 inches.  All of these dry periods began in December or January with the exception of the 1964-65 period which was 19 days but did not begin until February 6th.

Even the very wet El Niño seasons of 1982-83 and 1997-98 had intervening dry spells and 22 and 17 days respectively.

The bottom line is that an extended period of dry weather is the rule and not the exception in the middle of almost every winter as the atmosphere settles into a two to three week period of equilibrium dominated by high pressure.

Also posted at:  http://ggweather.com/enso/winter_dry_spells.htm
 

Season

Consecutive *Dry Days

Begin Date

*Intervening Days/Amount

San Francisco % of Average

ENSO Type

1950-51

13

17-Dec

 

111%

Weak La Niña

1951-52

12

6-Dec

1/.08

150%

Weak El Niño

1952-53

13

21-Jan

 

97%

Weak El Niño

1953-54

13

21-Dec

1/.01

66%

Weak El Niño

1954-55

16

14-Dec

 

73%

Weak La Niña

1955-56

20

28-Jan

 

126%

Moderate La Niña

1956-57

33

6-Dec

2/.03

69%

 

1957-58

8

6-Dec

 

169%

Strong El Niño

1958-59

12

12-Jan

 

48%

Weak El Niño

1959-60

13

15-Dec

 

71%

 

1960-61

36

19-Dec

1/.02

64%

 

1961-62

21

22-Dec

 

82%

 

1962-63

42

18-Dec

 

102%

 

1963-64

19

25-Dec

2/.08

57%

Moderate El Niño

1964-65

19

6-Feb

 

103%

Weak La Niña

1965-66

21

7-Jan

1/.02

75%

Strong El Niño

1966-67

30

11-Dec

1/.01

136%

 

1967-68

23

19-Jan

 

67%

Weak La Niña

1968-69

13

24-Dec

 

116%

Weak El Niño

1969-70

12

26-Dec

 

96%

Weak El Niño

1970-71

29

17-Jan

 

87%

Moderate La Niña

1971-72

21

30-Dec

 

51%

Weak La Niña

1972-73

15

24-Dec

 

159%

Strong El Niño

1973-74

11

20-Jan

 

128%

Strong La Niña

1974-75

22

5-Dec

2/.04

84%

Weak La Niña

1975-76

25

10-Jan

 

37%

Strong La Niña

1976-77

26

13-Jan

 

51%

Weak El Niño

1977-78

16

20-Jan

1/.02

124%

Weak El Niño

1978-79

15

19-Dec

 

87%

 

1979-80

26

18-Jan

 

113%

Weak El Niño

1980-81

16

5-Dec

 

71%

 

1981-82

12

6-Jan

 

171%

 

1982-83

22

24-Dec

 

176%

Very Strong El Niño

1983-84

15

31-Dec

 

104%

Weak La Niña

1984-85

11

27-Dec

 

92%

Weak La Niña

1985-86

21

8-Dec

 

132%

 

1986-87

15

7-Jan

 

64%

Moderate El Niño

1987-88

28

30-Jan

 

82%

Moderate El Niño

1988-89

11

11-Jan

 

81%

Strong La Niña

1989-90

36

26-Nov

 

66%

 

1990-91

17

20-Dec

 

65%

 

1991-92

17

8-Jan

1/.04

89%

Moderate El Niño

1992-93

14

22-Jan

 

123%

 

1993-94

20

15-Dec

1/.03

70%

 

1994-95

8

31-Jan

 

157%

Weak El Niño

1995-96

15

31-Dec

1/.02

115%

Weak La Niña

1996-97

20

27-Jan

2/.07

105%

 

1997-98

17

15-Dec

2/.03

218%

Very Strong El Niño

1998-99

21

21-Dec

2/.02

109%

Moderate La Niña

1999-00

27

14-Dec

1/.03

115%

Moderate La Niña

2000-01

22

16-Dec

1/.03

90%

Weak La Niña

2001-02

18

3-Jan

1/.02

116%

 

2002-03

19

24-Jan

 

110%

Moderate El Niño

2003-04

11

10-Dec

1/.04

95%

 

2004-05

17

9-Dec

 

147%

Weak El Niño

2005-06

14

3-Dec

1/.03

159%

 

2006-07

12

5-Jan

 

78%

Weak El Niño

2007-08

10

11-Jan

 

81%

Moderate La Niña

2008-09

18

3-Jan

 

84%

 

2009-10

12

31-Dec

1/.05

111%

Moderate El Niño

2010-11

14

31-Dec

 

133%

Moderate La Niña

2011-12

49

1-Dec

 

72%

Weak La Niña

2012-13

16

7-Jan

1/.01

77%

 

2013-14

36

12-Dec

2/.08

58%

 

2014-15

56

21-Dec

1/.07

84%

 



Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

Posted

SF Bay Area Meteorology Jobs

SF Bay Area Meteorology Jobs

 

In recent weeks a number of jobs for meteorologists in the SF Bay Area have crossed my desk that I thought I would share.  See below.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PG&E SENIOR METEOROLOGIST

Please note that Meteorology Services has a position available.  Please forward to all who may be interested in applying:

http://careers.pge.com/jobs/descriptions/senior-meteorologist-san-ramon-san-ramon-california-job-1-6013003

We are looking for a candidate with superb programming ability as the job will require at least half time building/maintaining data acquisition/dissemination and data-visualization systems.  

Please let me know any questions, 

Scott Strenfel - Supervisor, Meteorology
Applied Technology Services - Meteorology Services
3400 Crow Canyon Rd. #127, San Ramon, CA 94583
P: 925.866.5459 | C: 408.219.8136 | Weather Office: 925.244.4630

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
National Weather Service - Intern (Monterey and other locales) 

The NWS office in Monterey has an intern opening! This is a great chance for anyone who wants a job in the NWS since you will get exposure to working multiple desks plus outreach and computer programming. If there are any questions, let me know. https://www.usajobs.gov/GetJob/ViewDetails/423648100

Meteorologist (Intern)
www.usajobs.gov

This position is located in the National Weather Service Division of the National Ocean and Atmospheric Administartion.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SONOMA TECHNOLOGY

We are currently recruiting for several positions at Sonoma Technology, Inc.
(STI).

We are currently working on some very exciting projects; here are some examples:

Air Quality Forecasting and Public Outreach. STI meteorologists issue daily weather and air quality forecasts for over a dozen cities across the U.S.  These forecasts are disseminated to air quality agency websites and local and national media. STI meteorologists also develop forecast tools and provide forecast training to agencies worldwide.

Working with the U.S. EPA to Expand AirNow-International.
AirNow-International is a suite of state-of-the-art software programs based on the highly successful AirNow program (http://www.airnow.gov/). AirNow-I facilitates air quality management and promotes public awareness of air quality issues. The first implementation of the system was completed for Shanghai, China, in advance of the 2010 World Expo<https://www.youtube.com/watch?v=joljzDtA7FA>. It has since been expanded to other parts of China and Mexico.

Weather Research for Wind Energy. STI scientists are working with U.C. Davis to improve meteorological forecasts to support real-time wind energy production decisions. As part of this project, STI staff have deployed and are now operating instruments (sodars, ceilometers, radar wind profilers, and microwave radiometers) to continuously measure meteorology in the lower troposphere. Data from these instruments will be used to improve the physical parameterizations in the weather forecast models and improve initial conditions for input into the model.

Air Sensor Monitoring Program for Kids. STI is developing the Kids Making Sense<http://www.kidsmakingsense.org/> program, which enables youth to perform air quality measurements and empowers them to drive positive change in their communities.

I look forward to any questions or comments you may have about our company, projects, and staff.

Tim S. Dye<http://www.sonomatech.com/staff.cfm?uemployeeid=8>
Sr. Vice President, Meteorological and Air Quality Operations and Measurements Sonoma Technology, Inc.
1455 N. McDowell Blvd., Suite D
Petaluma, CA 94954-6503
p 707.665.9900
m 707.310.5541
tim@sonomatech.com
sonomatech.com

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GOOGLE - PROJECT LOON

I hope this email finds you well. I came across your information on LinkedIn and I was inquiring if you would have any interest in hearing about a Google - Project Loon - Atmospheric Scientist (https://youtu.be/OFGW2sZsUiQ) opportunity that I have available in the Mountain View, CA area? 

This is a contract to hire position, six months with potential to convert to full-time. 

Project Loon requires an Atmospheric Scientist's expertise in order to steer its balloon network through the Stratosphere. The goal of this project is to improve short, medium, and long-range weather forecast capabilities in support of Project Loon. 

Qualifications: 
• Degree in Atmospheric Science or related field
• Five plus of experience 
• Previous employment or experience with NOAA/ECMWF/NRL/NASA, etc.
• Intimately familiar with wind modeling and common wind models (e.g. GFS)

If you are interested and would like to see the position description please email me back and I will gladly send you the description.

Thank you and have a great day,

Intan (Lily) Lilyana 
Senior Technical Recruiter at Adecco Engineering & Technology, USA
lilyana.intan@adeccona.com

Is this storm El Niño? Or is it the next one?


Is this storm El Niño?

Yes and No! Every storm from now through winter and into spring is to some degree being influenced by El Niño. The conditions that define this strong El Niño are already in place across the eastern tropical Pacific. There are some winter weather patterns that are influenced more by this and thought of as more "typical" of El Niño, but even a cold front from the Gulf of Alaska is to some extent being impacted. The same can be said for every storm being influenced by the fact it is winter, with the tilt of the earth and its position relative to the sun being different than in summer! 



Consequently, there is no way to look at one storm (or any other weather event) and say it is or is not because of El Niño. We get storms every winter anyway and there is no DNA test to say that it is only happening because of El Niño.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

Posted

Which El Niño Index is Best?

Which El Niño Index is Best?

 

A Plethora of El Niño Indices

The November monthly Sea Surface Temperature Anomaly (SSTA) in Niño 3.4 region was a record +2.35, while the 3-month Oceanic Niño Index (ONI) for September-October-November is +2.04, second to a +2.18 for the same period in 1997.  So, is this the strongest El Niño on record or not? How about the monthly SSTA from December 1877 of +2.51?

In reality they are all correct as there is really no “best” metric. One may have elements that best describe a particular season in a particular location, while another may have the best teleconnection for a different time and place. 

A variety of different metrics are used to characterize El Niño; ranging from sea surface temperatures (SST) to sea-level pressure, surface winds, surface temperature and out-going longwave radiation. These are usually expressed in the form of an index; often in terms of the difference from long-term average (i.e., anomalies). Even indices based upon the same metric, like SST, may use different datasets, sampling periods (i.e., weekly, monthly, bi-monthly or tri-monthly) and/or different filtering techniques.

The Niño 3.4 region (map) has arguably the best teleconnections to seasonal weather in the United States and is widely used as a sampling area for SSTAs.

The Oceanic Niño Index (ONI), is the mostly widely used index in the United States to characterize El Niño events.  The ONI is the 3-month SST Anomaly (SSTA) for Niño 3.4 and calculated from moving 30-year average values. See http://ggweather.com/enso/oni.htm and http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml.

The Niño 3.4 region SST is also sampled on both a monthly (http://www.cpc.ncep.noaa.gov/data/indices/ersst4.nino.mth.81-10.ascii) and weekly (http://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for) using the ERSST4 dataset back to 1950. There is also monthly Niño 3.4 data going all the way back to 1870 using the HadISST1 dataset  (http://icdc.zmaw.de/1/daten/ocean/hadisst1.html).

The Southern Oscillation, which was identified by British mathematician Sir Gilbert Walker in the early 1900s, is a periodic "see-saw" of pressure patterns in the tropical Pacific. This pattern was later linked to occurrences of El Niño and is the SO part of the combined acronym ENSO for El Niño Southern Oscillation. It is usually expressesed as the standardized Southern Oscillation Index (SOI). See https://www.ncdc.noaa.gov/teleconnections/enso/indicators/soi/.

The El Niño Modoki (translated from Japanese for "similar but different") Index quantifies ENSO events that are warmer in the central Pacific than the typical El Niño warming in the eastern Pacific. See http://www.jamstec.go.jp/frcgc/research/d1/iod/enmodoki_home_s.html.en.

And the Multivariate ENSO Index (MEI) brings together six different elements (sea-level pressure, zonal and meridional surface wind, sea surface temperature, surface air temperature and total cloudiness). See http://www.esrl.noaa.gov/psd/enso/mei/.

An excellent technical analysis of these various indices by Anthony Barnston of IRI can be found at https://www.climate.gov/news-features/blogs/enso/why-are-there-so-many-enso-indexes-instead-just-one.

Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

Posted

All-Time Record Niño Region 3.4 Anomaly

All-Time Record Niño Region 3.4 Anomaly

 

The just updated Niño 3.4 region SST anomaly for November 2015 is +2.35.  This is the highest monthly SST anomaly (for any month) going back to the beginning of the dataset in 1950.  Previous the high was +2.33 in November 1997.



Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com

 

Posted