Not Necessarily the Worst Drought in 1200 years!

In the past week there has been extensive media coverage and headlines about "the worst California drought in 1200 years". This was based on a paper to be published in Geophysical Research Letters by the AGU. However a thorough reading of that paper,"How unusual is the 2012-2014 California drought?", indicates that this "worst" declaration should have at least a few asterisks. The article is not inaccurate but it takes only a limited view at looking at the current California drought.


- The study defines drought using the Palmer Drought Severity Index (PDSI). This is an agricultural index, based on soil-moisture as a function of both temperatue and precipitation. While, agriculture is incredibly important in California, it is not necessarily the best metric for the state's overall water deficit and its impacts.


- The paper also does not look at all of California. Instead it only examines the PDSI for central and southern California (i.e. NCDC California Climate Divisions 4, 5, 6, 7). This methodolgy gives a skewed prespective since much of the water used throughout the entire state originates in northern California (i.e., Climate Divisions 1,2,3) and the 3-year deficit has been less there than in the sampled southern two-thirds of the state. [For additional context see the just released NOAA California Drought Assessment.]


The bottom line is that the paper really only speaks to agricultural drought in central and southern California while both the Ranked 3-year Precipitation and PDSI show that currently the drought in northern California is only on the order of the 4th or 5th driest in the past 120 years; certainly not the driest in the past 1200 years statewide.

Jan Null, CCM
Golden Gate Weather Services


Posted

Impressive California 5-Day Totals

Compilation of 5-day rainfall statewide totals and current percent of normal.

 
...Northern California...

 

 

 

 

 

5-day

Season-

Current

 

29-Nov

30-Nov

1-Dec

2-Dec

3-Dec

Total

to-Date

% Normal

Crescent City

0.22

0.00

T

0.06

0.24

0.52

14.05

85

Eureka

0.76

T

0.00

0.10

0.27

1.13

12.16

125

Ukiah

0.11

0.37

0.18

0.30

1.67

2.63

9.05

121

Redding

M

0.29

0.08

0.12

1.30

1.79

11.02

137

Sacramento Exec AP

M

0.13

0.01

0.71

2.20

3.05

5.22

143

Sacramento - Csus

M

0.10

0.00

0.53

1.82

2.45

4.65

112

Santa Rosa

0.21

0.37

M

M

1.23

1.81

6.43

85

San Francisco

0.06

0.29

0.00

1.45

1.79

3.59

6.79

137

SFO Int'L Airport

T

0.29

T

1.55

1.55

3.39

5.86

152

Oakland Airport

0.02

0.22

T

1.18

1.06

2.48

5.05

121

Livermore

T

0.44

0.02

1.40

1.01

2.87

4.18

127

Mtn View - Moffett

0.34

0.46

0.12

1.14

1.84

3.90

5.08

190

San Jose

0.70

0.56

0.01

1.13

1.17

3.57

4.94

164

 

 

 

 

 

 

 

 

 

...Central California...

 

 

 

 

 

5-day

Season-

Current

 

29-Nov

30-Nov

1-Dec

2-Dec

3-Dec

Total

to-Date

% Normal

Stockton

0.04

0.43

0.00

1.10

0.17

1.74

3.62

121

Modesto

0.37

0.25

0.00

0.87

0.09

1.58

2.99

121

Merced

0.16

0.03

0.00

0.66

0.06

0.91

2.08

87

Madera

0.00

0.00

0.00

0.49

T

0.49

1.32

55

Fresno

0.00

0.01

0.00

0.42

T

0.43

1.51

75

Hanford

0.00

T

0.00

0.37

0.00

0.37

1.18

67

Bakersfield

0.00

0.00

0.00

0.44

0.00

0.44

1.1

97

Salinas

0.02

0.07

T

0.89

0.07

1.05

3.05

130

Paso Robles

0.00

0.17

T

0.66

0.07

0.90

2

95

Santa Maria

0.00

T

0.00

0.71

0.02

0.73

2.05

90

 

 

 

 

 

 

 

 

 

...Southern California...

 

 

 

 

 

5-day

Season-

Current

 

29-Nov

30-Nov

1-Dec

2-Dec

3-Dec

Total

to-Date

% Normal

Sandberg

0.00

0.04

0.00

1.32

0.49

1.85

2.75

159

Palmdale

0.00

T

0.00

1.18

0.01

1.19

1.37

73

Lancaster

0.00

T

0.00

1.10

0.07

1.17

1.54

111

Santa Barbara

0.00

T

T

2.06

0.22

2.28

3.72

127

Camarillo

0.00

0.07

0.00

1.15

0.12

1.34

2.13

93

Burbank - Bob Hope

0.00

0.43

0.00

1.06

0.04

1.53

2.32

92

LAX Int'L Airport

0.00

0.22

0.00

1.05

0.17

1.44

2.14

102

Los Angeles / Usc

0.00

0.21

0.00

1.15

0.20

1.56

2.19

102

Long Beach

0.00

0.05

0.10

0.90

0.40

1.45

2.58

128

Fullerton

0.00

0.03

0.01

0.58

0.22

0.84

1.86

81

Irvine - John Wayne

0.00

0.02

0.00

0.29

0.09

0.40

0.78

33

Oceanside

0.00

0.00

0.00

0.09

0.35

0.44

1.75

75

Ramona

0.00

T

0.00

0.06

0.31

0.37

2.27

86

San Diego - Lindbergh

0.00

0.00

0.00

0.02

0.26

0.28

1.13

59

Ontario

0.00

0.16

0.00

0.84

0.16

1.16

2.96

121

Riverside

0.00

T

0.00

0.05

0.04

0.09

0.69

39

Palm Springs

0.00

0.00

0.00

0.13

0.03

0.16

1.62

82

Thermal

0.00

0.00

0.00

T

0.01

0.01

0.46

43

Campo

0.00

0.00

0.00

0.08

1.14

1.22

3.76

108

 

Jan Null, CCM
Golden Gate Weather Services

Posted

Biggest 2-day and 3-day Rain Events in San Francisco

Through 7 am San Francisco had received 1.36" of rainfall since midnight, which combined with 1.61" received yesterday gives a 2-day total of 2.97".  With more rain on the way this looks to be the rainiest 2 days in San Francisco since at least January 2008.

The table below has the rainiest 2-day and 3-day events since 2000.

It should be noted that the one-day record in San Francisco is 5.54" on Nov. 5, 1994.  http://ggweather.com/sf/top%2020%20wettest.html 

 

    2-day 3-day
1/18/2010 0.99    
1/19/2010 1.24 2.23  
1/20/2010 1.03 2.27 3.26
       
2/15/2009 2.18    
2/16/2009 0.79 2.97  
2/17/2009 0.87 1.66 3.84
       
1/25/2008 3.19    
1/26/2008 0.38 3.57  
1/27/2008 0.38 0.76 3.95
       
12/17/2005 1.14    
12/18/2005 2.15 3.29  
12/19/2005 0.20 2.35 3.49
       
12/16/2004 0.84    
12/17/2004 2.61 3.45  
12/18/2004 0.31 2.92 3.76
       
12/13/2002 2.99    
12/14/2002 0.81 3.80  
12/15/2002 0.42 1.23 4.22
       
2/11/2000 1.23    
2/12/2000 0.53 1.76  
2/13/2000 2.08 2.61 3.84
 Jan Null, CCM
Golden Gate Weather Services
Posted

California Drought - Good News, Bad News

Great soaking rain across much of California and we will see many rainfall season-to-date percent of normal rainfall jump significantly.  Some to above normal. (see http://www.cnrfc.noaa.gov/awipsProducts/RNOWRKCLI.php  which is reissued daily at 6 PM).  This is all good and every inch of rain helps ease the drought.


But, looking at the broader picture of the deficits from the last 3 seasons (2011-12, 2012-13, 2013-14) shows what a long uphill battle it will be.  For example, the 3-season deficit for San Francisco at the beginning of the rainfall season was 26.07 inches. If you add that to the 23.65 inches needed for this season to ultimately reach normal we would need 49.73 inches to be at "normal".  The all-time rainiest season in SF history was 1861-62 when there was 49.27".  Or for every 1 inch of rain in San Francisco we will only erase about 3% of this long term deficit!


Below is a table of the rainfall to date (through 6 pm last night) for the combined last 3 seasons plus this season-to-date, thge deficit and the percent of normal.

 

3+ seasons to date

 

Rain

Normal

Deficit

% Normal

...Northern California...

 

 

 

 

 

 

 

 

 

Crescent City

161.95

208.18

-46.23

78%

Eureka

105.93

130.18

-24.25

81%

Ukiah

79.01

119.21

-40.20

66%

Redding

79.23

111.53

-32.30

71%

Sacramento Exec Airport

39.46

59.02

-19.56

67%

Sacramento - Csus

42.23

64.77

-22.54

65%

Santa Rosa

69.81

116.13

-46.32

60%

San Francisco

48.27

75.63

-27.36

64%

SFO Int'L Airport

37.75

65.60

-27.85

58%

Oakland Airport

41.68

66.44

-24.76

63%

Livermore

28.37

50.31

-21.94

56%

Mountain View - Moffett

25.31

46.59

-21.28

54%

San Jose

25.43

47.63

-22.20

53%

 

 

 

 

 

...Central California...

 

 

 

 

 

 

 

 

 

Stockton

27.96

45.05

-17.09

62%

Modesto

26.85

41.70

-14.85

64%

Merced

21.34

39.82

-18.48

54%

Madera

21.59

38.40

-16.81

56%

Fresno

19.72

36.43

-16.71

54%

Hanford

13.05

32.03

-18.98

41%

Bakersfield

11.15

20.49

-9.34

54%

Salinas

27.40

40.72

-13.32

67%

Paso Robles

19.49

40.36

-20.87

48%

Santa Maria

21.75

44.02

-22.27

49%

 

 

 

 

 

...Southern California...

 

 

 

 

 

 

 

 

 

Sandberg

16.18

38.63

-22.45

42%

Palmdale

10.00

26.74

-16.74

37%

Lancaster

8.57

23.48

-14.91

36%

Santa Barbara

29.01

56.10

-27.09

52%

Camarillo

19.44

47.87

-28.43

41%

Burbank - Bob Hope

20.90

54.34

-33.44

38%

LAX Int'L Airport

19.80

40.47

-20.67

49%

Los Angeles / Usc

21.40

46.83

-25.43

46%

Long Beach

19.88

38.69

-18.81

51%

Fullerton

17.60

43.86

-26.26

40%

Irvine - John Wayne

15.19

42.31

-27.12

36%

Oceanside

19.88

43.25

-23.37

46%

Ramona

28.85

50.64

-21.79

57%

San Diego - Lindbergh

20.04

32.84

-12.80

61%

Ontario

20.57

47.49

-26.92

43%

Riverside

13.17

38.91

-25.74

34%

Palm Springs

7.73

19.15

-11.42

40%

Thermal

5.97

10.64

-4.67

56%

Campo

29.78

50.56

-20.78

59%

 

Jan Null, CCM
Golden Gate Weather Services

Wettest SF Day Since ?

Through 8 am this morning downtown San Francisco had received 1.13 inches of rain.  Below are the 25 rainiest days (midnight to midnight) in downtown SF since July 1, 2009.  The current total would make it the only the wettest day since last February, BUT with rain continuing to fall today's total should climb rapidly up the list.

rank

date

rain

1

10/13/2009

2.48

2

2/15/2009

2.18

3

3/14/2012

1.47

4

1/20/2012

1.41

5

12/19/2010

1.27

6

2/22/2009

1.24

7

1/19/2010

1.24

8

3/24/2011

1.24

9

4/12/2012

1.24

10

3/24/2012

1.23

11

12/28/2010

1.21

12

11/7/2010

1.18

13

4/17/2010

1.17

14

12/25/2012

1.15

15

2/8/2014

1.15

16

2/9/2014

1.13

17

3/19/2011

1.12

18

2/28/2014

1.12

19

12/2/2012

1.06

20

2/19/2011

1.05

21

2/17/2011

1.04

22

1/20/2010

1.03

23

12/8/2010

1.02

24

12/23/2012

1.00

 

Jan Null, CCM
Golden Gate Weather Services

Posted

November California Rain and Temperature Summary

Despite the recent rain, California ended up with below normal rainfall in November 2014. Precipitation ranged from 82% of normal at Redding to 48% at Sacramento in northern California, 93% at San Jose to 37% in Fresno in central California and from 46% in Los Angeles to 37% in San Diego.


In terms of the droughtit is important to note, that even reaching "normal to date" rainfall for this season does not address the carry-over deficits from the past two seasons.

Temperatures were universally above normal, ranging from 1.8 above normal at Redding to 5.3 above normal at San Diego.


See http://ggweather.com/calif/nov2014.htm 

 Jan Null, CCM
Golden Gate Weather Services

Posted

Was a Strong 2014 El Niño Really Ever Forecast?

Given the headlines and breathless commentators in the Spring and early Summer of 2014 there seemed to have been wide expectations of a strong El Niño beginning about now.  But was a strong El Nino really ever forecast for this winter?

 

A look at the monthly IRI mid-month forecasts beginning in February would argue, with the exception of a blip in April into the low-moderate category, that the 25 models represented in the IRI "plume" have consistently been portraying a weak event.  [That blip and some of the April hypebole may have been the result of the extensive sub-surface pool of anomalously warm water being transported eastward by a large Kelvin wave at the time.] 


The values portrayed in the graph below are the averages for the forecast members from the dynamic and statistical model categories and then the overall average.  But even looking at individual members, there was no month with mone than one member into the strong category, and most had none.

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

 If you have trouble viewing the image below, it can also be found at:  http://ggweather.com/enso/fcsts.jpg 

 

Posted

1962 SF World Series Rainout

With the  possibility of some scattered showers lingering into gametime (5 pm pdt) of the 4th game of the World Series on Saturday, here are some links looking back to a much more dramatic event.  In 1962, the 6th game of the World Series between the Giants and Yankees was washed out by the infamous "Columbus Day Storm".


Historic Newsreel Footage of 1962 Storm
http://ggweather.com/1962storm.MP4 


Summary of 1962 Storm from Mark McLaughlin
http://thestormking.com/tahoe_nuggets/Nugget_151/nugget_151.html 


Summary of Columbus Day Storm Review
http://oregonstate.edu/ua/ncs/archives/2012/oct/fifty-years-later-legacy-columbus-day-storm-still-stands 


Bay Area Storm Index - 2nd Strongest Bay Area Storm
http://ggweather.com/basi.htm

 

Jan Null, CCM

Posted

Alternate Satellite Imagery Sites

Most National Weather Service satellite images (produced by NESDIS) continue to be unavailable with no estimated ETA.  Here are some alternate sources:

Univ of Wash
http://www.atmos.washington.edu/data/ 

San Jose State Univ
http://www.met.sjsu.edu/weather/sat2/ 

Oregon State Univ
http://www.ocs.orst.edu/goes-images 

San Franciscos State Univ
http://virga.sfsu.edu/crws/satimg.html 

Univ of Wisconsin
http://www.ssec.wisc.edu/data/geo/index.php?satellite=west&file=jpg 

Navy Research Lab
http://www.nrlmry.navy.mil/sat-bin/epac_westcoast.cgi 

Penn State Univ
http://mp1.met.psu.edu/~fxg1/SAT_WEST/recentir.html 

IPS
http://wxweb.meteostar.com/models/noaaport_loop.php?PATH=/var/www/leads_images/satellite/SYS/COMP/ 

Unisys
http://weather.unisys.com/satellite/index.php 

 

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

Posted

Warm and Wet California September...Except Where It Wasn't

See:  http://ggweather.com/calif/sep2014.htm 

Most of California ended the month with above normal temperatures, with average maxima ranging from 1.4 above normal at Sacramento to 5.1 above normal in San Diego (one of their warmest on record).  The exceptions were San Francisco and San Jose, the victim of June gloom that has over-stayed its welcome, which had anomalies of -0.3 and -1.9 respectively.

Northern and Central California posted some gaudy monthly percent of normal (PoN) rainfall numbers, due in part to the relatively low normal rainfall amounts and to the over-producing storm on the the 25th.  Eureka led the pack with 520% and Redding was close behind at 505%.  Totals dropped off from north to south with Fresno at just 106% of normal, while the South Coast was close to zero.  

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

FYI - I am posting less via this email server and relying more on Twitter for short quick messages.  Please follow me there:  @ggweather

 Jan Null, CCM 

 

Posted