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/


 
Posted

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/

 

Posted

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/


Posted

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/



 
Posted

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/

 

Posted

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/

 

Posted

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/

Posted

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/

 

Posted

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/

 

Posted

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

 

Posted