From the Department of Water Resources:
The Department of Water Resources has finished the April 12, 2022 Bulletin 120 (B120) forecast update. The forecast includes observed conditions through the morning of Tuesday, April 12, 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
Forecast Summary:
The projected median April-July (AJ) runoff ranges in the major Southern Cascades/Sacramento River basins from 21 percent of average for the Trinity River basin to 53 percent of average for the Pit River basin, in the major San Joaquin River basins from 24 percent of average for the Cosumnes River basin to 50 percent of average for the San Joaquin River basin, and in the major Tulare basins from 19 percent of average for the Tule River basin to 43 percent of average for the Kings River basin.
Since the April 1 B120 was issued, the AJ forecasts for most river basins have decreased between 1 and 5 percent of average due to below median precipitation in the first third of April. The Feather River basin forecast was the only to increase, rising 2 percent of average due to higher than expected flows since April 1. Forecasts in the McCloud, Pit, and American River basins remain unchanged since the April 1 B120.
Runoff:
Since April 1, daily full natural flow rates have mostly fluctuated up and down during the first week and then declined during the second week due to overcast skies and decreasing temperatures. The Trinity and Sacramento River have shown response to the recent rainfall, increasing over the past few days. The Trinity and Sacramento Region rivers are running below half of their respective April average flow rate, except for the American River which is running at 56 percent of average. All rivers in the San Joaquin and Tulare Lake basins are flowing above 60 percent of average, except for the Cosumnes, Tule, and Kern rivers which are flowing decidedly lower. The Trinity, Sacramento, Cosumnes and Tule rivers are flowing at a rate equal to or less than 30 percent of average for the month.
Unimpaired flows in Percent of Average for Water Year 2022 are as follows:
|
River |
Oct |
Nov |
Dec |
Jan |
Feb |
Mar |
Oct-Mar |
Apr (Month to Date) |
|
Trinity |
312 |
195 |
40 |
46 |
32 |
28 |
49 |
24 |
|
Shasta |
104 |
104 |
72 |
67 |
29 |
25 |
53 |
30 |
|
Sacramento at Bend Bridge |
125 |
115 |
76 |
54 |
25 |
23 |
51 |
30 |
|
Feather |
348 |
137 |
117 |
74 |
45 |
47 |
79 |
42 |
|
Yuba |
566 |
163 |
117 |
58 |
35 |
42 |
74 |
49 |
|
American |
814 |
198 |
144 |
58 |
40 |
48 |
80 |
56 |
|
Sacramento Region |
233 |
131 |
99 |
60 |
33 |
35 |
64 |
|
|
Cosumnes |
1334 |
151 |
254 |
51 |
28 |
22 |
66 |
22 |
|
Mokelumne |
732 |
234 |
135 |
58 |
49 |
58 |
87 |
74 |
|
Stanislaus |
432 |
161 |
146 |
47 |
47 |
56 |
77 |
63 |
|
Tuolumne |
384 |
176 |
143 |
45 |
39 |
49 |
74 |
73 |
|
Merced |
277 |
167 |
140 |
42 |
36 |
51 |
65 |
83 |
|
San Joaquin |
282 |
170 |
215 |
71 |
67 |
73 |
102 |
86 |
|
San Joaquin Region |
402 |
176 |
165 |
52 |
45 |
53 |
79 |
|
|
Kings |
96 |
100 |
126 |
54 |
49 |
59 |
68 |
73 |
|
Kaweah |
70 |
49 |
99 |
38 |
34 |
42 |
47 |
61 |
|
Tule |
65 |
29 |
95 |
35 |
22 |
26 |
36 |
29 |
|
Kern |
51 |
58 |
72 |
45 |
37 |
34 |
45 |
40 |
|
Tulare Region |
76 |
74 |
104 |
48 |
41 |
47 |
56 |
|
Precipitation:
As of the morning of April 14th, despite recent precipitation events, all three precipitation indices have accrued precipitation at a rate well below average for the month of April. However, significant precipitation forecast over the next week has the potential to finally end the three-month streak of well below average precipitation in the Northern and Central Sierra.
Precipitation summary for Water Year 2022 as of April 14, 2022:
|
Region |
Percent of Average |
Precipitation (inches) |
||||||||
|
Oct |
Nov |
Dec |
Jan |
Feb |
Mar |
Apr (Month to Date) |
WY to Date |
Apr (Month to Date) |
WY to Date |
|
|
Northern Sierra 8-Station Index |
453 |
58 |
144 |
14 |
4 |
16 |
16 |
73 |
0.7 |
33.9 |
|
San Joaquin |
314 |
25 |
195 |
0 |
2 |
26 |
14 |
65 |
0.5 |
22.6 |
|
Tulare Basin |
216 |
7 |
221 |
0 |
9 |
31 |
4 |
60 |
0.1 |
15.0 |
Snowpack:
The statewide snow water equivalent (SWE) based on snow sensors is 6.6 inches which corresponds to 25 percent of normal for this date and 24 percent of the April 1 average. Since April 1, the statewide snowpack has decreased by 3.7 inches. Snowmelt was high at the start of the month with increased temperatures and solar radiation but recent precipitation has added back to the snowpack over the last three days.
The regional snowpack levels as of the morning of April 14, 2022 stand at the following (based on snow sensors):
|
Region |
No. of Stations |
Avg. SWC |
Percent of April 1 |
Percent of Normal |
|
Northern |
29 |
5.0 |
18 |
20 |
|
Central |
44 |
8.2 |
27 |
28 |
|
Southern |
25 |
5.9 |
24 |
25 |
|
Statewide |
98 |
6.6 |
24 |
25 |
Weather and Climate Outlooks:
According to CNRFC 6-day forecast, significant precipitation is forecasted across the Northern two thirds of the state. The present front is expected to continue to move across the state before clearing on Sunday with another storm following behind it. The highest totals of precipitation are forecasted for the Northern Sierras and North Coastal range with potential totals in excess of 5 inches in some places. The Central Coast and Central Valley are forecast to receive up to an inch of precipitation with levels declining farther south. Freezing levels are currently at 4,000-6,000 feet in the northern basins and 6,000-7,000 feet in the southern Sierras. For the northern basins, the freezing level will increase to 7,000-8,000 feet by Sunday and then begin to decline starting Monday. The freezing elevation will increase to 9,000-11,000 by Sunday for the southern Sierras for the rest of the forecast window. Southern California freezing levels are currently 10,000-12,000 feet and will slowly rise across the forecast window.
The NWS Climate Prediction Center (CPC) one‐month outlook issued on March 31, 2022, suggests equal chances of above or below normal temperatures throughout the northern quarter of the state; it suggests above average chances for higher-than-normal temperatures in the remainder of the state. The same forecast suggests the entire state has slightly increased chances for below normal precipitation for April.
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 CPC on April 11, 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 update forecast for conditions as of April 19, 2022, will be available on Thursday, April 21st. 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 ***
