tag:ggweather.posthaven.com,2013:/posts Golden Gate Weather Services 2019-06-28T15:32:25Z Jan Null tag:ggweather.posthaven.com,2013:Post/1425463 2019-06-28T13:58:42Z 2019-06-28T15:32:25Z 2018-2019 California Rainfall Season - Good but not Great This Sunday, June 30th, marks the end of the 2018-2019 California rainfall season. Below are summaries of rainfall across the state. An important takeaway, despite "record-setting" headlines, is that for the vast majority of the state it was only a "good" above-normal year and not even in the top 20% of the wettest seasons. [Data also at https://ggweather.com/ca2018rain.htm and https://ggweather.com/water/]



San Francisco
POR begins 1849-1850
2018-19: 25.50, 109%
Rank: 40th of 170 seasons

San Jose
POR begins 1892-1893
2018-19: 16.63, 112%
Rank: 36th of 127 seasons

Eureka
POR begins 1886-1887
2018-19: 41.00, 102%
Rank: 50th of 133 seasons
 
Redding
POR begins 1892-1893
2018-19: 39.92, 115%
Rank: 38th of 127 seasons
 
Sacramento
POR begins 1940-1941
2018-19: 24.57, 133%
Rank: 12th of 70 seasons
 
Fresno
POR begins 1881-1882
2018-19: 11.44, 99%
Rank: 32nd of 138 seasons
 
Los Angeles
POR begins 1876-1887
2018-19: 18.82, 126%
Rank: 39th of 143 seasons
 
San Diego
POR begins 1850-1851
2018-19: 12.41, 120%
Rank: 36th of 169 seasons
 
8-Station Index
Northern Sierra Nevada
POR begins 1921-1922
2018-19: 68.44, 126%
Rank: 19th of 98 seasons
 
5-Station Index
Central Sierra Nevada
POR begins 1913-1914
2018-19: 49.79, 117%
Rank: 22nd of 106 seasons
 
6-Station Index
Southern Sierra Index
POR begins 1922-1923
2018-19: 37.06, 122%
Rank: 23rd of 97 seasons


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather


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Jan Null
tag:ggweather.posthaven.com,2013:Post/1408925 2019-05-14T14:13:30Z 2019-05-14T17:47:11Z May Rainfall Climatology

 

With the rain looking likely over the next week or so, below is some May rainfall climatology for the Bay Area and California.






 Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather


]]>
Jan Null
tag:ggweather.posthaven.com,2013:Post/1406035 2019-05-06T17:43:50Z 2019-05-06T17:46:28Z El Niño keep chugging along

  

For the past 5 months, the Oceanic Niño Index (ONI) has been stuck in the middle of the Weak El Niño category (i.e., +0.50 and +1.0) and the models are keeping it in that range through the end of the year!  Going back to 1950 (https://ggweather.com/enso/oni.htm) there are only three back-to-back years with kind of similar patterns, but none close enough in my estimation to be reasonable analogs. They were 1968-69 to 1969-70, 1986-87 to 1987-88, and 2014-15 to 2015-16.  California precipitation patterns related to El Niño years can be found at https://www.ggweather.com/ca_enso/ca_elnino.html


 


Current SST Temperatures with Niño Region insets


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather






 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1404077 2019-05-01T17:06:40Z 2019-05-01T17:13:07Z A Dry April, but Still Looking Good

 

After well above normal February and March rainfall, percentages in April across most of California dropped to well below normal. However, season-to-date numbers are still mostly above normal, and in many locations their seasonal (July 1 to June 30) normals have already been reached. See https://ggweather.com/seasonal_rain.htm and https://ggweather.com/water/.





Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1386098 2019-03-15T18:08:14Z 2019-03-15T19:04:15Z "Storm" - Still relevant after almost 80 years


“ STORM” by George R. Stewart, should be REQUIRED READING if you are a meteorologist, meteorology student, deal with or communicate California weather on a regular basis, or anyone whose day-to-day activities in California are impacted by the weather.  I have just finished rereading it for probably the 5th time and couldn’t put it down.

I first read “Storm” when I was an NWS meteorologist intern in 1975 and identified with one of the characters in the book, the Junior Meteorologist (JM) at the Weather Bureau in San Francisco. Over the years, I have given or loaned copies to over a dozen friends and colleagues and even though it was written in 1941, the meteorology is still sound and incredibly insightful. Likewise, the impact of a storm across California for 12 days in a winter where there had been early talk of a drought resonates strongly with this year’s headlines. Interwoven throughout the book are the interactions between the weather, the utilities, railroads, commerce, the airlines and people, which are just as relevant today as they were almost 80 years ago.



Please, do yourself a favor and track down a copy. It’s in many libraries, plus I often find copies squirreled away in used bookstores and there are numerous versions available on Amazon. (And when you finish “Storm”, read Stewart’s “Fire” which looks at another timely topic, the impact of a wildfire in the Sierra Nevada.)

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1384834 2019-03-12T17:22:20Z 2019-03-12T17:31:39Z Comparison of the 2018-2019 Winter Outlooks to Reality?

 

How did the 2018-2019 Winter Outlooks that were issued last fall compare with reality? This year, in addition to looking at the CPC forecasts, several outlooks from the private sector were added for comparison. In all of the outlooks I see big-time errors; begging the question is there "skill" and "value" in these products? See http://ggweather.com/cpc/2019/


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1382709 2019-03-07T17:36:38Z 2019-03-07T17:39:37Z California Rainfall and Reservoir Update

 

2018-2019 CALIFORNIA WATER BY THE NUMBERS

It's should be no surprise that abundant rainfall this season has translated into a pretty bright picture for water supplies across the Golden State. 

The latest Drought Monitor shows California with its least amount of drought-impacted area since 2011. With only 0.60% in the Moderate Drought category (D1) and 9.56% in D0 (Abnormally Dry), California is at its most drought free since 8-30-2011. 

 The latest California Precipitation Snapshot shows rainfall already approaching or above normals for the entire is rainfall season (July 1 to June 30).

Of particular note is the 8-Station Northern Sierra Index, with state's largest reservoirs, which is now at 128% of normal and just 2.33" shy of their seasonal normal of 54.52".

  
And all of the above translates into California reservoir levels close to or exceeding historical averages for this time of year. 


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1370421 2019-02-04T19:25:15Z 2019-02-04T19:27:05Z February 5th Bay Area Snow; But Not like 1887 or 1976


Historically, February 5th is the snowiest day of the year in San Francisco and the Bay Area. Of the 11 days when snow has been recorded near sea level in San Francisco, twice before on February 5th. In 1887 and again in 1976. (https://www.ggweather.com/sf/snow.htm)


The event on February 5, 1887, was the snowiest on record with over 3 inches in the downtown area of the City.  This is well documented in Mark McLaughlin's wonderful  "San Francisco Snowstorms" document (http://thestormking.com/Sierra_Stories/San_Francisco_Snowstorms/san_francisco_snowstorms.html)


And the last time there was an accumulation of snow near sea level in San Francisco was on February 5, 1976, with up to an inch downtown and 5" on Twin Peaks. (Spectacular photograph below: Art Frisch, SF Chronicle), 



The forecast conditions for tomorrow, February 5, 2019, do NOT look like a repeat of either one of the previous snow events. But the combination of much colder air moving into the region and continued bands of showers overnight should at least whiten the hills above 2000' and in some areas, especially inland possibly down to into the 1000' to 1500' range.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather


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Jan Null
tag:ggweather.posthaven.com,2013:Post/1364319 2019-01-17T17:47:23Z 2019-01-17T17:49:03Z Significant Rainfall Gains Statewide


The first 16 days of January have seen great rainfall recoveries across California from recent storms. Most locales have jumped by about 20% versus their Jan. 1st %-of-normal numbers. The very important 8-Station N Sierra Index (8SI) has jumped to 89% of normal while both Redding and Sacramento are now just above normal. For others see below or https://www.ggweather.com/water/.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather



 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1357709 2018-12-27T21:21:28Z 2018-12-27T21:22:08Z California Rainfall Update and Odds

 

With no rain in the forecast through the end of the year, here are some updates on where California stands precipitation-wise. Most of the state north of the Tehachapis is about 75% of normal, while to the south it is averaging from near to slightly above normal.

Through Dec 31, San Francisco will be at 5.95 inches or 65% of normal. This is the 63rd driest out of the 170 seasons dating back to 1849. Looking at the 30 seasons that had this value plus/minus an inch, the corresponding end of the rainfall season (Jul 1 through Jun 30) totals ranged from 11.06" to 27.86". This breaks down further with 6 seasons at < 60% of normal, 11 seasons at 61-80% of normal, 8 seasons at 81-100% and 5 seasons in the 100 to 120 percent of normal. 

https://www.ggweather.com/water/
 





Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1347307 2018-11-25T21:20:44Z 2018-11-25T21:21:49Z Significant Rainfall Gains

Last week's rains made a significant dent in California rainfall deficits, pushing many northern California areas from around 10% of their normal late November rainfall to over 50% of normal. And forecast charts continue to show at least moderate rain at times this week in the Tuesday through Thursday timeframe. See https://www.ggweather.com/seasonal_rain.htm and https://www.ggweather.com/water/









 

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1339280 2018-11-02T14:09:55Z 2018-11-02T14:11:53Z A dry start to the SF rainfall season; What does it mean?

 

So far, the 2018-2019 rainfall season has been pretty dry, with only 0.21” having fallen in downtown San Francisco. But it is far from the driest, with 26, out of 169 previous July 1st to October 31st totals having lesser amounts.

Looking at the 47 seasons that ranged from 0.00” to 0.42” for teh first 4 months of the rainfall season:
25 (53%) ended with less than 80% of normal by June 30th,
15 (32%) ended with between 80% and 120% of normal, and
7 (15%) of the seasons finished with more than 120% of normal.

It is interesting to note that both San Francisco’s all-time driest and wettest seasons began dry. The driest was 1850-1851 with a July to October total of 0.33” and a final seasonal total of just 7.42”. Conversely, 1861-1862, after having only 0.02” through October, finished with a fantastic (except for the flooding) record season of 49.27”.

List of the 48 driest beginnings to the SF rainfall season:

 

 

 

End of Season

Rank

Season

Jul-Oct

Total

% Normal

1

1855-1856

0.00

21.66

92%

2

1905-1906

0.00

20.42

86%

3

1929-1930

0.01

16.28

69%

4

1932-1933

0.01

14.93

63%

5

1861-1862

0.02

49.27

208%

6

1915-1916

0.02

27.12

115%

7

1917-1918

0.02

11.48

49%

8

1863-1864

0.03

10.08

43%

9

1870-1871

0.03

14.11

60%

10

1880-1881

0.05

29.86

126%

11

2002-2003

0.05

23.87

101%

12

1995-1996

0.06

24.89

105%

13

1928-1929

0.07

15.21

64%

14

1955-1956

0.07

27.17

115%

15

1952-1953

0.08

21.10

89%

16

1871-1872

0.09

30.78

130%

17

1859-1860

0.10

22.27

94%

18

2003-2004

0.10

20.54

87%

19

1866-1867

0.11

34.92

148%

20

1980-1981

0.11

14.63

62%

21

1868-1869

0.15

21.35

90%

22

1872-1873

0.16

15.66

66%

23

1903-1904

0.17

20.59

87%

24

1949-1950

0.18

16.78

71%

25

1978-1979

0.19

18.70

79%

26

2015-2016

0.20

23.26

98%

27

2018-2019

0.21

??

??

28

1958-1959

0.21

10.46

44%

29

1875-1876

0.24

31.19

132%

30

1867-1868

0.24

38.84

164%

31

1946-1947

0.27

14.89

63%

32

1966-1967

0.27

29.41

124%

33

1911-1912

0.28

14.06

59%

34

1887-1888

0.30

16.74

71%

35

1914-1915

0.31

27.41

116%

36

1961-1962

0.33

17.65

75%

37

1850-1851

0.33

7.42

31%

38

1890-1891

0.33

17.58

74%

39

1948-1949

0.33

18.28

77%

40

1993-1994

0.33

15.22

64%

41

1864-1865

0.35

24.73

105%

42

1971-1972

0.35

11.06

47%

43

1990-1991

0.36

14.08

60%

44

2008-2009

0.36

18.11

77%

45

1893-1894

0.39

18.47

78%

46

1906-1907

0.40

26.17

111%

47

1953-1954

0.41

14.27

60%

48

2017-2018

0.42

17.53

74%

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Twitter: @ggweather
 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1333918 2018-10-19T17:56:56Z 2018-10-19T17:59:16Z CPC Winter Outlooks and an Updated El Niño Forecast

 

 

With the latest NOAA 2018-2019 Winter Outlook just released, here's how the previous three CPC Winter Precipitation Outlooks "verified". At least here on the West Coast they seem to have pretty much missed the mark.



And the just updated IRI/CPC Oceanic Niño Index (ONI) forecast is significantly warmer than last month's; pushing the winter months into the moderate El Niño category.

However, even in the moderate El Niño category there is still a large range of solutions and little predictive value. See https://www.ggweather.com/ca_enso/ca_elnino.html for the California and https://www.ggweather.com/enso2016/us_elnino.html for the US.



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Web: http://ggweather.com
Twitter: @ggweather
 

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1327940 2018-10-01T20:04:40Z 2018-10-01T20:05:42Z New & Improved El Niño (and La Niña) California Precipitation Climatology


The Climate Prediction Center (CPC) currently has an El Niño Watch for this coming Fall and Winter, though they have been gradually decreasing its probability of occurrence in recent months.


I have put together a new & improved comprehensive California Precipitation climatology for ENSO (i.e., El Niño and La Niña) events. See 
https://www.ggweather.com/ca_enso/ca_elnino.html and https://www.ggweather.com/ca_enso/ca_lanina.html.



The climatology is based upon the 10 California Hydrologic regions (map) and generated with the updated (and excellent) Western Region Climate Center's California Climate Tracker tools.

As always, corrections, comments and corrections are greatly appreciated.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com
Facebook: Golden-Gate-Weather-Services
Twitter: @ggweather

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1320787 2018-09-11T19:39:31Z 2018-09-11T19:41:20Z PG&E and SoCal Edison Mesonets

In recent months both Pacific Gas & Electric (PG&E) and Southern California Edison (SCE) have been installing extensive weather station networks. Primarily mounted on utility poles they gather wind, temperature and humidity data every 10 minutes. Currently PG&E has about 100 stations online and SCE about 70 stations; and it is my understanding that more are being installed. (San Diego Gas & Electric (SDG&E) has had a similar mesonet of about 150 stations for about 5 years) The data is available on MesoWest and on via NWS graphical interface. However, neither MesoWest or the NWS page let's one parse out just these mesonets, so I have put together a couple pages, both in tabular and map/graphical form.

PG&E: Table, Map 
SCE: TableMap
SDG&E mesonet
These have both been added to the Mesonet section on my Meteorologist Links page.

Enjoy and please let me know of any comments or suggestions.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/




 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1318314 2018-09-04T16:15:38Z 2018-09-04T16:20:49Z California Summer Temps Mostly Above Average - Recap

 

Meteorological summer (i.e., June, July, August) has ended and most of the Golden State ended up with above normal temperatures. The biggest anomalies were over the southern half of the California and over the northern interior.  



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1314773 2018-08-24T15:55:15Z 2018-08-24T15:58:08Z San Francisco still a month away from average hottest day


San Francisco is still a month away from their normal hottest day of the year! Conversely, most other cities around California and the nation are well past their normal hottest day, which typically occurs about a month after the Summer Solstice. But a few locations, especially along the West Coast, wait until August and even September to peak. And San Francisco is certainly the latest of any major United States city by not reaching its normal highest maximum temperature of 70.4 until September 24t.
Source: http://ggweather.com/normals/daily.htm 

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 
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Jan Null
tag:ggweather.posthaven.com,2013:Post/1312116 2018-08-15T18:08:42Z 2018-08-15T18:11:31Z El Niño Rainfall Climatology


With the eastern tropical Pacific warming and most forecasts leaning toward at least a weak El Niño event this coming winter I have put together a new climatology looking at early-August conditions relative to the subsequent rainfall season.  I have also updated several previous ENSO climatologies with regards to rainfall and temperatures.

 

New: Early August Comparative Weak/Moderate El Niño Seasonal Rainfall Climatology 



Updated: US Winter Precipitation & Temperature Climatologies: El Niño  |  La Niña
Updated: California El Niño Precipitation Climatology
Updated: California La Niña Precipitation Climatology 

Updated links to all of the above and more at EL NIÑO / LA NIÑA RESOURCE PAGE


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Jan Null
tag:ggweather.posthaven.com,2013:Post/1298095 2018-06-29T13:53:20Z 2018-06-29T13:54:35Z Summary of California 2017-2018 Rainfall Season Ending Tomorrow

The California 2017-2018 rainfall season ends tomorrow with totals across the state below normal and on the order of half of the totals recorded in 2016-17. See http://ggweather.com/ca2017rain.htm and http://ggweather.com/ca2016rain.htm.



See also the Precipitation Snapshot at http://ggweather.com/water/



Also the Western Region Climate Center's Precipitation Anomaly maps from https://wrcc.dri.edu/anom/cal_anom.html



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 
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Jan Null
tag:ggweather.posthaven.com,2013:Post/1284918 2018-05-18T17:10:56Z 2018-05-18T17:13:01Z Updated Resource Pages; Tioga Pass by the Nummbers


I have updated the following Weather Resource pages for 2018. But please let me know of any errata, suggestions or additions. Enjoy.

2018 Thunderstorm and Tornado Resource Guide

2018 Hurricane Resource Guide

2018 Fire Weather Resource Guide


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

With Tioga Pass due to open Monday (5/21/2018) here are some historical records going back to 1980.



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/


 
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Jan Null
tag:ggweather.posthaven.com,2013:Post/1269640 2018-04-06T18:09:13Z 2018-04-06T18:10:48Z Beware Daily Weather Records!!

 

During big rain events, a particular rainfall amount may be touted as record rainfall for the date, just as during hot weather the temperature may be proclaimed a daily maximum record. Ideally, meteorological data should be based on where we are in our orbit around the sun and not a particular calendar day. This is because our calendar is slightly flawed when it comes to specific days as it takes 365.25 days to circle the sun giving us a leap day every four years.

Consequently, the dates in a leap year after February 29th, are all displaced by one day. That is, April 6th in 2017, 2018 and 2019 is the 96th day of the year, while April 6th in a leap year (i.e., 2016, 2020) is the 97th day. So, if a record event for a particular date happened in a leap year versus a non-leap year we are actually comparing different days based upon of position relative to the "solar year".

For example, the largest rainfall amount for San Francisco for April 21st is 1.39” in 1880, a leap year so it was the 112th day of that year. But the record for April 22nd, is 0.43” in 2007, not a leap year so it is also the 112th day of the year!
Which is correct?  The bottom line is that neither is really right all of the time!
 

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com 
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1268998 2018-04-04T23:19:27Z 2018-04-04T23:21:02Z 1 & 2-Day SF Bay Area April Rainfall Records

  

1 and 2 Day SF Bay Area April Rainfall Records

 

One Day Record

Two Day Record

 

 Name

Rain (in.)

Date

Rain (in.)

Date

Since

ALAMEDA COUNTY

 BERKELEY

2.49

 1896-04-24 

4.04

 1958-04-02 

1893

 FREMONT

0.96

 2003-04-13 

1.62

 2003-04-13 

1996

 HAYWARD AIR TERMINAL

0.98

 2012-04-10 

1.65

 2003-04-13 

1998

 LIVERMORE

1.80

 1958-04-03 

2.10

 1958-04-04 

1903

 LIVERMORE MUNICIPAL AP

1.14

 2003-04-12 

1.79

 2003-04-13 

1998

 NEWARK

1.41

 2003-04-13 

1.46

 2003-04-14 

1906

 OAKLAND INTL AP

2.03

 1974-04-01 

2.24

 2012-04-13 

1948

 OAKLAND MUSEUM

2.07

 1974-04-01 

2.10

 1974-04-02 

1970

 TRACY PUMPING PLANT

1.10

 1983-04-28 

1.70

 1983-04-28 

1955

 UPPER SAN LEANDRO FILTERS

2.20

 1974-04-02 

3.12

 1974-04-02 

1948

CONTRA COSTA COUNTY

 CONCORD BUCHANAN FIELD

0.97

 2012-04-12 

1.54

 2017-04-07 

1999

 CONCORD WASTEWATER PLANT

1.20

 2017-04-07 

1.91

 2017-04-08 

1991

 MARTINEZ WATER PLANT

1.50

 2003-04-13 

1.81

 2017-04-08 

1970

 MOUNT DIABLO JUNCTION

2.35

 1958-04-03 

2.90

 1958-04-04+

1952

 RICHMOND

2.32

 1953-04-27 

2.48

 1982-04-11 

1950

MARIN COUNTY

 KENTFIELD

4.95

 1935-04-07 

5.31

 1935-04-08 

1902

 SAN RAFAEL-CIVIC CENTER

4.39

 1896-04-25 

5.24

 1958-04-02 

1894

MONTEREY COUNTY

 BIG SUR STATION

4.50

 1982-04-11 

6.37

 1982-04-11 

1915

 CARMEL VALLEY

1.60

 2006-04-05 

2.27

 2006-04-05 

1959

 KING CITY

1.58

 1982-04-10 

2.25

 1912-04-10 

1902

 MONTEREY

2.11

 1974-04-01 

2.36

 1912-04-11 

1906

 MONTEREY PENINSUL AP

1.23

 1969-04-05 

1.47

 1969-04-06 

1968

 MONTEREY WFO

1.45

 2006-04-04 

1.68

 2006-04-04 

1995

 SALINAS AP

2.15

 1974-04-01 

2.15

 1974-04-02 

1930

 SALINAS NO. 2

2.09

 1974-04-01 

2.58

 1974-04-02 

1958

NAPA COUNTY

 ANGWIN PACIFIC UNION COL

3.08

 1982-04-11 

3.82

 1982-04-11+

1940

 CALISTOGA

2.65

 1911-04-05 

5.26

 1996-04-02 

1906

 MARKLEY COVE

2.64

 1982-04-11 

2.94

 1982-04-12 

1970

 NAPA COUNTY AIRPORT

1.07

 2017-04-06 

1.85

 2017-04-07 

1998

 NAPA STATE HOSPITAL

2.66

 1996-04-01 

3.23

 1958-04-03 

1893

 SAINT HELENA

3.52

 1927-04-01 

5.64

 1926-04-05 

1907

 SAINT HELENA 4 WSW

2.20

 2010-04-12 

2.88

 2017-04-08+

1948

SAN BENITO COUNTY

 HOLLISTER 2

1.43

 1981-04-19 

1.63

 1981-04-20 

1948

 PANOCHE 2 W

1.14

 1958-04-03 

1.24

 1957-04-18 

1949

 PINNACLES NM

2.17

 1958-04-03 

2.39

 1958-04-04 

1937

SAN FRANCISCO COUNTY

 SAN FRANCISCO DOWNTOWN

3.45

 1853-04-16 

3.59

 1853-04-17 

1849

 SAN FRANCISCO OCEANSIDE

1.45

 1978-04-15 

1.50

 1978-04-16 

1948

SAN MATEO COUNTY

 HALF MOON BAY

2.36

 1941-04-04 

2.54

 1953-04-27 

1939

 REDWOOD CITY

2.54

 1958-04-02 

3.90

 1958-04-02 

1906

 SAN FRANCISCO INTL AP

2.30

 1958-04-02 

3.21

 1958-04-02 

1945

 SKYLINE RIDGE PRESERVE

2.75

 2003-04-13 

2.96

 2003-04-13 

1995

SANTA CLARA COUNTY

 GILROY

3.65

 1958-04-03 

4.07

 1958-04-04 

1906

 LOS GATOS

3.70

 1901-04-29 

5.89

 1958-04-02 

1893

 MOFFETT FEDERAL AIRFIELD

1.17

 1958-04-02 

1.73

 1983-04-28 

1945

 MOUNT HAMILTON

1.87

 1965-04-09 

3.38

 1965-04-10 

1948

 SAN JOSE

1.46

 1983-04-28 

2.06

 2006-04-04 

1893

 BEN LOMOND NO. 4

5.35

 1941-04-04 

7.15

 1958-04-02 

1937

 SANTA CRUZ

3.75

 1923-04-04 

4.05

 1923-04-05 

1893

 WATSONVILLE MUNICIPAL AP

1.51

 2006-04-04 

2.24

 2012-04-13 

1945

 WATSONVILLE WATERWORKS

2.85

 1983-04-28 

3.15

 1983-04-29 

1908

SONOMA COUNTY

 BODEGA 6 WSW

2.28

 2010-04-11 

2.42

 2010-04-12 

2008

 CLOVERDALE

2.80

 1982-04-11 

4.20

 2010-04-12 

1950

 FORT ROSS

4.23

 1953-04-27 

5.36

 1953-04-27 

1895

 GRATON

4.00

 1953-04-27 

4.61

 1926-04-05 

1926

 HEALDSBURG

3.25

 1953-04-27 

4.57

 1927-04-02 

1893

 OCCIDENTAL

5.20

 1953-04-27 

5.49

 1953-04-28 

1943

 PETALUMA AIRPORT

2.45

 1941-04-04 

4.40

 1926-04-05 

1893

 SANTA ROSA

3.06

 1926-04-04 

5.99

 1926-04-05 

1902

 SANTA ROSA SONOMA CO AP

2.36

 2017-04-06 

2.77

 2017-04-07 

1998

 VENADO

4.68

 2006-04-12 

5.29

 2017-04-08 

1948



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/


]]>
Jan Null
tag:ggweather.posthaven.com,2013:Post/1267808 2018-04-01T20:47:30Z 2018-04-01T20:48:43Z California April 1st Precipitation Update

 

March rainfall and snowfall across California saw the most significant gains in the Sierra Nevada Precipitation Indices where the average percentage of normal jumped from 41% of normal-to-date to 69% of normal. See http://ggweather.com/water/



Also http://ggweather.com/seasonal_rain.htm and 


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/



 
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Jan Null
tag:ggweather.posthaven.com,2013:Post/1264166 2018-03-22T19:01:54Z 2018-03-22T19:03:43Z California March Rainfall Summary - No Miracle 


As rainfall begins to taper off in many parts of the state, the historical context is that this is more of a Mediocre March than a Miracle March!  Rainfall today and a few showers over the weekend will add a little bit to the numbers below but in general the models have a pattern shift to high pressure and dry weather for next week. The bottom line is that while there have been good gains in rainfall statewide this month, most of California has a near zero chance of reaching normal for the season. 


The March 2018 values above are through midnight March 21.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com   
Web: http://ggweather.com 
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1262080 2018-03-16T17:14:37Z 2018-03-16T17:19:42Z March 15th California Rainfall Deficits

 

The table below shows the current rainfall to date, the amount of rain (i.e., deficit) to reach the June 30 normal, and what the amount of "normal" rainfall is between now and June 30. For example, San Francisco is 11.22", which means we would need another 12.43" between now and June 30, BUT normal between now and then is just another 3.76"; so we would need over 3.3 times normal!
 

 

CALIFORNIA RAINFALL DEFICITS

Northern California

Rain thru

Deficit to End of

Normal

15-Mar

Season Normal

Mar 16-Jun 30

Crescent City

35.62

28.41

14.19

Eureka

27.27

13.06

8.43

Ukiah

16.23

21.12

6.79

Montague/Siskiyou

4.84

13.63

4.82

Alturas

6.81

7.36

4.64

Mount Shasta City

14.72

28.49

8.83

Redding

13.89

20.73

6.82

Sacramento Exec AP

11.18

7.34

3.22

Sacramento - CSUS

11.68

8.59

3.55

Blue Canyon

34.78

29.84

13.80

Santa Rosa

17.63

18.65

5.71

San Francisco Downtown

11.22

12.43

3.76

SFO Airport

10.28

10.37

3.16

Oakland Airport

10.18

10.63

3.61

Livermore

7.83

7.88

2.61

Mountain View - Moffett

6.64

8.04

2.56

San Jose

6.49

9.33

2.92

Nrn Sierra Index - 8SI

28.94

25.58

11.78

Central California...

Rain thru

Deficit to End of

Normal

15-Mar

Season Normal

Mar 16-Jun 30

Stockton

6.27

7.79

2.57

Modesto

4.84

8.27

2.62

Merced

4.18

8.32

2.53

Madera

3.69

8.33

2.29

Fresno

3.53

7.97

2.54

Hanford

3.05

7.05

2.01

Bakersfield

2.75

3.72

1.35

Bishop

0.22

4.96

0.87

Salinas

3.74

9.09

2.40

Paso Robles

4.94

7.84

2.00

Santa Maria

3.64

10.31

2.49

Cntrl Sierra Index - 5SI

18.66

23.91

9.66

Srn Sierra Index - 6SI

10.17

20.33

6.72

Southern California

Rain thru

Deficit to End of

Normal

15-Mar

Season Normal

Mar 16-Jun 30

Sandberg

5.60

6.73

1.81

Palmdale

1.55

6.75

1.21

Lancaster

1.85

5.53

0.95

Santa Barbara

5.52

12.24

2.77

Camarillo

3.04

12.18

1.81

Burbank - Bob Hope

4.80

12.51

2.72

LAX Airport

2.90

9.92

1.72

Los Angeles Downtown

3.37

11.56

2.22

Long Beach

2.94

9.32

1.61

Fullerton

2.72

11.16

1.77

Irvine - John Wayne

1.43

11.90

1.68

Oceanside

3.89

9.77

1.96

Ramona

5.44

10.60

2.78

San Diego - Lindbergh

2.99

7.35

1.74

Ontario

3.00

12.04

2.07

Riverside

4.12

8.28

1.69

Palm Springs

3.66

2.08

0.42

Thermal

1.76

1.44

0.22

Campo

4.23

11.50

2.37

Barstow-Daggett

1.13

2.93

0.48

Needles

1.24

3.38

0.57


Season to date percent of normal rainfall.


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1257225 2018-03-05T17:10:38Z 2018-03-05T17:11:39Z Sierra Snow: Great for Skiers, Less so for Water Supply

Despite impressive snow depths of the past week's storms, the more important metric in terms of California's water supply is the amount of water equivalent. And here, all that fluffy powder fell short with its ratios of between 16 and 25 inches of snow to an inches of water. consequently the important Sierra Indices (below) only showed modest increases.  




Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

]]>
Jan Null
tag:ggweather.posthaven.com,2013:Post/1254678 2018-03-01T15:31:01Z 2018-03-01T15:34:04Z Don't Count on a Miracle March (or April) to Save the Day

  

Despite this morning's soggy San Francisco beginning to the month of March, the historic odds of even getting close to normal are near zero; even with an above normal March AND April.

After late evening rain on February 28th, San Francisco doubled their monthly total from 0.21" to 0.42". This pushed them down (up?) to the 16th driest out of 169 years in SF February rainfall records. It also pushed the 8-month total for the rainfall season to date (i.e., July 1 to Feb. 28) to 9.03", the 17th lowest on record.

A look at San Francisco's rainfall seasons following such a dry first eight months shows that it has never recovered, even with substantial March and April rains, to even close to normal. Of all the years that saw less than 11 inches of rain in this period, only one (1898-99) made it to 71% of normal by the end of the season with 16.87".

For seasons with only between 8" and 10" of rain on March 1st, the average March-April totals have been just 3.08", or 65% of normal for the two-month period.  



Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1250922 2018-02-21T20:58:14Z 2018-02-21T20:59:59Z San Francisco's Dismally Dry Days Continue

  

Today (Wed, 2/21) marks the 27th consecutive winter day that San Francisco has NOT had measurable rainfall this season. (The last day of rain in the City was January 25th.) This makes it the 13th longest winter dry spell beginning in December, January or February over San Francisco's 169 season history.

Probably the first real "chance" of rain is next Monday, which would make the streak 31 days and tied for the 5th longest. 


Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com  
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1244536 2018-02-08T17:17:30Z 2018-02-08T17:19:21Z San Francisco Winter Dry Spells


As of today, February 8, there has been no measurable rainfall (i.e., 0.01" or greater) in San Francisco for 14 days and no rain in the forecast for at least another week. Mid-winter dry spells are NOT unusual (see http://ggweather.com/enso/winter_dry_spells.htm ), but how far would we need to go extend the current dry streak to make it into record territory? Actually a lot farther!

If we had no rain in the next two weeks, that would bring the total number of consecutive dry days to 28, the 9th longest streak in SF's 169 year period of record. And if extended through the end of the month that would bring the total to 34 days or 4th longest.

Note in the table below that the winter of 2014-2015 had two of the top six dry spells with a 43 day period from late December into February (43 days), almost immediately followed by a 30 day dry spell into early March! 



Jan Null, CCM
Adjunct Professor of Meteorology
San Jose State University
Phone: (408) 379-7500
Email: jan.null@sjsu.edu

 

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Jan Null
tag:ggweather.posthaven.com,2013:Post/1243992 2018-02-07T16:51:59Z 2018-12-28T16:57:13Z Defining Drought ... It's Not Just Rainfall


Defining Drought … It’s Not Just the Rainfall

It seems that whenever California is beginning to see areas with below normal rainfall, even before the halfway point of the rainfall season, the D” word starts making its way into many media articles. But, what exactly is constitutes a “drought”. There is no simple answer and it certainly depends on who ask and where they live.

The American Meteorological Society defines drought as “A period of abnormally dry weather sufficiently long enough to cause a serious hydrological imbalance”. The important takeaway from this broad brush definition is the use of term “hydrological imbalance” and not rainfall deficit. This is especially true in California where the State’s diverse infrastructure means water falling in the northern half of the state strongly impacts hydrologic imbalances many hundreds of miles away in the south.

Broadly, drought can be subdivided into four categories: meteorological drought, hydrological drought, agricultural drought, and socioeconomic drought.

Meteorological drought is a measure of the “degree of dryness” resulting from rainfall and snowfall deficits. There is additionally a very important temporal aspect which impacts the other types of drought by its dependence on not only the degree of deficit but also its longevity. These deficits can be measured as the number of days without rain or the percent of an average amounts of precipitation over days, months, years of even decades.

Hydrological drought is a measure of water supply available from rivers, reservoirs and groundwaters; and the infrastructure to distribute that water. The temporal aspect is even more important with hydrological drought as there can be significant time lags between when precipitation occurs and it impacts surface or subsurface supplies. [This is one of the reasons that meteorologists in California and the West use July 1 to June 30 rainfall season as opposed to the hydrologist’s October 1 to September 30 water year (http://ggweather.posthaven.com/rainfall-season-vs-water-year)]  

Agricultural droughts operate on a short time scale as a precipitation deficit during even a short growing season can have significant impacts. These impacts are exacerbated (or mitigated) by crop type, the availability of stored water (i.e., hydrologic drought) plus soil type and moisture.

Socioeconomic drought is the impact on human activities and the related economies and is a function of all the previous three types of drought as well as metrics like population change and water usage patterns.

A variety of indices and other metrics have been developed to attempt to quantify drought, though one that is good for agricultural drought may not be as adept at capturing socioeconomic impacts.

The bottom line is that drought has many intersecting layers and the effects of any or all of these drought types is dependent upon the user and his location. Drought is complicated!

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Phone: (408) 379-7500
Email: jnull@ggweather.com 
Web: http://ggweather.com
Twitter: https://twitter.com/ggweather
Facebook: https://www.facebook.com/Golden-Gate-Weather-Services-151100414926621/


Additional Resources:
American Meteorological Society (AMS) https://www.ametsoc.org/ams/index.cfm/about-ams/ams-statements/archive-statements-of-the-ams/meteorological-drought/
National Drought Mitigation Center (NDMC)
http://drought.unl.edu/DroughtBasics/TypesofDrought.aspx
National Center for Environmental Information (NCEI)
https://www.ncdc.noaa.gov/monitoring-references/dyk/drought-definition
Western Region Climate Center (WRCC)
https://wrcc.dri.edu/Water/drought.php

 

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Jan Null