From the Department of Water Resources:
We have finished the March 28, 2022 Bulletin 120 (B120) forecast update. The forecast includes observed conditions through the morning of Monday, March 28, 2022.
The forecasts are posted at:
- B120 Update: https://cdec.water.ca.gov/reportapp/javareports?name=B120UP
- B120 Update WY Distribution: https://cdec.water.ca.gov/reportapp/javareports?name=B120DIST
A third year of drought:
Extreme dry conditions since January 1 throughout the state and including in the major snow bearing watersheds of the Sierra Nevada and Southern Cascade mountains have resulted in a statewide snowpack that is at 39 percent of average to date. The snowpack which was once well above average around the first of the year have suffered from the driest January, February, and March on record. For the second consecutive year, California has experienced unprecedented hydroclimate conditions. The snowpack is now below the level it was at just a year ago. While the statewide snowpack has been this low or even lower (the lowest on record for April 1 conditions was 5% of average on April 1, 2015), the frequency at which the snowpack on or near April 1 is at or below 50% of average has increased since the year 2000.
During March, California has seen long periods of well above average temperatures which has increased snowmelt at levels that normally would be expected in April or May. While many foothill reservoirs have seen an increase in inflow due to this early snowmelt, the fact remains that the already low snowpack is quickly diminishing. The low snowpack and early melt are being driven by California’s warmer and drier climate, and these conditions solidify the fact that California will endure its third consecutive year of drought.
Forecast Summary:
The projected median April-July (AJ) runoff ranges in the major Southern Cascades/Sacramento River basins from 31 percent of average for the Trinity River basin to 55 percent of average for the Pit River basin, in the major San Joaquin River basins from 29 percent of average for the Cosumnes River basin to 55 percent of average for the San Joaquin River basin, and in the major Tulare basins from 21 percent of average for the Tule River basin to 50 percent of average for the Kings River basin.
Since the March 1 B120 was issued, the AJ forecasts for most river basins have decreased between 8 percent and 15 percent due to the continued dry conditions and substantial pre-April melt. Decreases have been even more significant in the Feather (19 percent), Yuba (20 percent), and American (24 percent) river basins. Decreases in snow in these three basins throughout March have been especially severe, particularly at low elevations. Since last week’s forecast update, forecasts have dropped between 1 and 7 percent.
Runoff:
Since March 22, full natural flow rates increased due to snowmelt and recent precipitation. However, over the last few days flows in most basins have begun to recede from their peak earlier this week. All rivers are running below half of their respective March average flow rate, excluding the Mokelumne, Stanislaus, and San Joaquin which are currently at 60, 55, and 71 percent of average, respectively. Five rivers (Trinity, Shasta Total Inflow, Sacramento at Bend Bridge, Cosumnes, and Tule) are flowing at a rate less than 30% of average for the month.
Unimpaired flows in Percent of Average for Water Year 2022 are as follows:
|
River |
Oct |
Nov |
Dec |
Jan |
Feb |
Oct-Feb |
Mar (Month to Date) |
|
Trinity |
312 |
195 |
40 |
46 |
32 |
59 |
26 |
|
Shasta |
104 |
104 |
72 |
67 |
29 |
63 |
25 |
|
Sacramento at Bend Bridge |
125 |
115 |
76 |
54 |
25 |
60 |
23 |
|
Feather |
348 |
137 |
117 |
74 |
45 |
93 |
45 |
|
Yuba |
566 |
163 |
115 |
57 |
35 |
87 |
38 |
|
American |
814 |
198 |
144 |
58 |
40 |
95 |
48 |
|
Sacramento Region |
233 |
131 |
99 |
60 |
33 |
75 |
|
|
Cosumnes |
1334 |
151 |
254 |
51 |
28 |
89 |
20 |
|
Mokelumne |
732 |
234 |
135 |
58 |
49 |
103 |
60 |
|
Stanislaus |
432 |
161 |
146 |
47 |
47 |
89 |
55 |
|
Tuolumne |
384 |
176 |
143 |
45 |
39 |
86 |
47 |
|
Merced |
277 |
167 |
140 |
42 |
36 |
72 |
46 |
|
San Joaquin |
282 |
170 |
215 |
71 |
67 |
117 |
71 |
|
San Joaquin Region |
402 |
176 |
165 |
52 |
45 |
93 |
|
|
Kings |
96 |
100 |
126 |
53 |
51 |
72 |
37 |
|
Kaweah |
70 |
49 |
99 |
38 |
34 |
49 |
40 |
|
Tule |
65 |
29 |
95 |
35 |
22 |
40 |
26 |
|
Kern |
51 |
58 |
72 |
45 |
37 |
50 |
33 |
|
Tulare Region |
76 |
74 |
104 |
47 |
42 |
60 |
|
Precipitation:
Even with recent rainfall, March remains well below average with none of the three indices recording more than 1.7” of precipitation. With only two days remaining in the month, all three precipitation indices are less than a third of average for March. March will conclude a three-month period of well below average precipitation.
Precipitation summary for Water Year 2022 as of March 30, 2022:
|
Region |
Percent of Average |
Precipitation (inches) |
|||||||
|
Oct |
Nov |
Dec |
Jan |
Feb |
Mar (Month to Date) |
WY to Date |
Mar (Month to Date) |
WY to Date |
|
|
Northern Sierra 8-Station Index |
453 |
58 |
144 |
14 |
4 |
16 |
75 |
1.3 |
33.2 |
|
San Joaquin |
314 |
25 |
195 |
0 |
2 |
26 |
67 |
1.7 |
22.1 |
|
Tulare Basin |
216 |
7 |
221 |
0 |
9 |
31 |
63 |
1.4 |
14.9 |
Snowpack:
The statewide snow water equivalent (SWE) based on snow sensors is 11.0 inches which corresponds to 39 percent of normal for this date. Since March 1, the statewide snowpack has decreased by 4.8 inches, with 3 inches melting in the past 7 days.
The regional snowpack levels as of the morning of March 30, 2022 stand at the following (based on snow sensors):
|
Region |
No. of Stations |
Avg. SWC |
Percent of April 1 |
Percent of Normal |
|
Northern |
31 |
8.3 |
30 |
30 |
|
Central |
42 |
13.0 |
43 |
43 |
|
Southern |
26 |
11.1 |
44 |
44 |
|
Statewide |
99 |
11.0 |
39 |
39 |
Weather and Climate Outlooks:
According to CNRFC 6-day forecast, small, scattered precipitation is forecasted for the Southern Sierras and San Gabriel mountains in totals less than a tenth of an inch over the first day of the forecast. The entire state is not forecasted to see any more precipitation except the North Coast which is expected to see a front move through on the last day of the forecast window with precipitation totals of less than half an inch. Freezing levels are expected to remain somewhat consistent over the six-day forecast with levels between 8,000-10,000 feet in the Northern Basins and 9,000-12,000 feet in the Southern Sierras and in Southern California.
The NWS Climate Prediction Center (CPC) one‐month outlook issued on March 17, 2022, suggests equal chances of above or below normal temperatures throughout the northern half of the state; it suggests above average chances for higher-than-normal temperatures in the southern half. The southern 2/3rds of the state has increased chances for below normal precipitation whereas the northern third has equal chances of above or below normal precipitation.
The CPC three-month (April-May-June) outlook, issued on March 17, 2022, suggests equal chances of above or below normal temperatures for the central coast and northern third of the state; for the rest of the state increased chances of above average temperatures are expected. The outlook also shows equal chances of above or below normal precipitation for the southern half of the state and increased chances of below normal precipitation for the northern half.
According to the latest El Niño/Southern Oscillation (ENSO) discussion issued by the Climate Prediction Center on March 28, 2022, La Niña conditions are present. Equatorial sea surface temperatures (SSTs) are below average across the east-central and eastern Pacific Ocean. The tropical Pacific atmosphere is consistent with La Niña. These conditions are favored to continue into the Northern Hemisphere summer (53 percent chance during June-August 2022), with a 40-50 percent chance of La Niña or ENSO-neutral thereafter.
Next Update:
A Bulletin 120 forecast and a Water Supply Index (WSI) forecast for conditions as of April 1, 2022, will be concurrently available on Friday, April 8th. If you have any questions regarding this forecast, please contact a member of the Snow Surveys and Water Supply Forecasting staff.
Important Links:
Full Natural Flow Data:
- Daily FNF
- Monthly FNF
- Seasonal FNF
- Tableau Dashboard – Historical FNF Comparison (Interactive Data Visualization)
- Tableau Dashboard – Daily FNF (Interactive Data Visualization)
Precipitation Data:
- Latest Northern Sierra 8-Station Precipitation Index Tabular Data
- Latest San Joaquin 5-Station Precipitation Index Tabular Data
- Latest Tulare Basin 6-Station Precipitation Index Tabular Data
- Latest Northern Sierra 8-Station Precipitation Index Plot
- Latest San Joaquin 5-Station Precipitation Index Plot
- Latest Tulare Basin 6-Station Precipitation Index Plot
Snow Data:
- Latest Snow Sensor Report
- Latest Statewide Summary of Snow Water Equivalents
- Tableau Dashboard – Regional Snow Water Equivalent Comparison (Interactive Data Visualization)
Extended Regional Forecasts:
- California Nevada River Forecast Center 6 Day QPF and Snow Level Forecast
- Climate Prediction Center One-Month Outlook Forecasts
- Climate Prediction Center Three-Month Outlook Forecasts
- U.S. Seasonal Drought Outlook
- Weather Forecast Office California Service Area-Products
- El Niño Southern Oscillation (ENSO) Conditions and Weekly Discussion (including La Niña)
- Atmospheric River Scale Forecast Products
Bulletin 120:
- Tableau Dashboard – Snow Product Comparison for WY2022 (Interactive Data Visualization) *** NEW ***
- Tableau Dashboard – Bulletin 120 Forecast Performance Over Time (Interactive Data Visualization)
- Historical Forecast Error Plots
Other Useful Links:
- California Water Watch *** NEW ***
- U.S. Department of Agriculture California Climate Hub by California State Climatologist *** NEW ***
