Groundhog Day has its roots in an ancient Celtic celebration called Imbolog. This date is the midpoint between the winter solstice and the spring equinox. In an agrarian society that was very dependent on the weather, this was a time to celebrate having made it halfway through winter. The superstition arose that if the weather was fair on Imbolog, the second half of the winter would be cold and stormy, but if the weather was cold and overcast or stormy, the second half of the winter would be mild.
Across much of Northern and Central California there has been little if any rain this month and monthly totals will wind up at or near long term records. Below are the 15 lowest January totals for each station's period of record.
Looking at San Francisco, note that three of the five driest years are in the top five. This has brought the average for the past ten years down to 3.03, dramatically lower than the 30-year normal of 4.55 inches.
In San Francisco, January 19th begins the second half of the July 1 to June 30 rainfall season. A few other cities in Northern California reached their halfway point in the past few days and most of the state will exceed it in the next week.
Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com
jnull@ggweather.com
Happy New Year and Best Wishes for a healthy, happy and properous 2015.
December 2014 was a wet and warm month across the Golden State. Precipitation ranged from "only" 120% of normal at Eureka to 294% at Los Angeles and 297% at San Jose. December maxima were well above normal, ranging from 1.6 degrees above normal at Redding to 5.9 above normal at Sacramento; with the exception of Los Angeles whose maxima were 0.2 below normal.
December California Key City Climatology
http://ggweather.com/calif/dec2014.htm
December Max Anomaly Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc30dTxdep.gif
December Mean Anomaly Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc30dTvdep.gif
December Min Anomaly Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc30dTndep.gif
December Precipitation Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc30dP.gif
December Precipitation % of Normal Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc30dPpct.gif
July - December Precipitation Table
http://www.cnrfc.noaa.gov/awipsProducts/RNOWRKCLI.php
July - December % of Normal Map
http://www.wrcc.dri.edu/cgi-bin/anomimage.pl?wrc6mPpct.gif
Northern Sierra Nevada 8-Station Index
http://cdec.water.ca.gov/cgi-progs/products/PLOT_ESI.pdf
Southern Sierra Nevada 5-Station Index
http://cdec.water.ca.gov/cgi-progs/products/PLOT_FSI.pdf
California Snow Water Content
http://cdec.water.ca.gov/cgi-progs/products/PLOT_SWC.pdf
Jan Null, CCM
http://ggweather.com
With the recent rains I have been re-asked the eternal question: "Should I Walk or Run in the Rain?" This is a classic question that meteorologists get asked and upon which we have probably spent way too much time. So, does a person make impact with more droplets as they run faster even though they are exposed for a shorter period of time? Or do more drops hit the front of a running person than on their head and shoulders when they run instead of walk?
There have even been a number of studies to "scientifically'' calculate whether it's better to run or walk to shelter. One of the simpler studies had people wear a piece of cardboard over their heads and in front of them as they walked or ran through the rain and then the number of drops that marked the cardboard were counted. A more detailed effort from the National Climatic Data Center in Asheville, North Carolina had their experimental subjects wear identical moisture absorbing clothing as they walked 100 yards at 3 mph and then ran the same course at 9 mph. Their clothing was then weighed to find out how much water was absorbed. They found that speed helps ... the person who ran the course absorbed 40 percent less water than the walker!
And of course someone, again with way too much time on their hands, has put up a website to calculate how wet you would get based upon your size, speed and the rate of rainfall. See http://www.dctech.com/physics/notes/0006.php and http://www.dctech.com/physics/notes/0005.php.
Stay dry!
Jan Null, CCM
Golden Gate Weather Services
http://ggweather.com
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
Links referenced above:
http://www.whoi.edu/page.do?pid=50242&tid=3622&cid=207049
http://www.drought.gov/drought/content/products-current-drought-and-monitoring-drought-indicators/palmer-drought-severity-index
http://cpo.noaa.gov/sites/cpo/MAPP/Task%20Forces/DTF/californiadrought/California_Drought_2-pager.pdf
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
Compilation of 5-day rainfall statewide totals and current percent of normal.
|
|
|
|
|
|
|
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
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 |
Golden Gate Weather Services
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