Bill Commons

CA SB 599

enacted

Atmospheric rivers: research: forecasting methods: experimental tools.

California · 2025-2026 Regular Session · upper

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Quick answers

Did CA SB 599 pass?

Yes. CA SB 599 has been enacted into law. Latest recorded action (2026-09-27): Chaptered by Secretary of State. Chapter 650, Statutes of 2026.

What is CA SB 599 about?

Existing law establishes the Atmospheric Rivers Research and Forecast Improvement Program: Enabling Climate Adaptation Through Forecast-Informed Reservoir Operations and Hazard Resiliency (AR/FIRO) Program in the Department of Water Resources. Existing law requires the department to operate reservoirs in a manner that improves flood protection, and to reoperate flood control and water storage facilities to capture water generated by atmospheric rivers. Existing law requires the department to research, develop, and implement new observations, prediction models, novel forecasting methods, and tailored decision support systems to improve predictions of atmospheric rivers and their impacts on water supply, flooding, post-wildfire debris flows, and environmental conditions. This bill would, for novel forecasting methods researched, developed, and implemented by the department, require the department to include the use of experimental tools that produce seasonal and subseasonal atmospheric river forecasts, as defined.

Who sponsors CA SB 599?

Caballero is the primary sponsor of CA SB 599.

Description

Existing law establishes the Atmospheric Rivers Research and Forecast Improvement Program: Enabling Climate Adaptation Through Forecast-Informed Reservoir Operations and Hazard Resiliency (AR/FIRO) Program in the Department of Water Resources. Existing law requires the department to operate reservoirs in a manner that improves flood protection, and to reoperate flood control and water storage facilities to capture water generated by atmospheric rivers. Existing law requires the department to research, develop, and implement new observations, prediction models, novel forecasting methods, and tailored decision support systems to improve predictions of atmospheric rivers and their impacts on water supply, flooding, post-wildfire debris flows, and environmental conditions. This bill would, for novel forecasting methods researched, developed, and implemented by the department, require the department to include the use of experimental tools that produce seasonal and subseasonal atmospheric river forecasts, as defined.

Introduced
2025-02-20
Latest action
2026-09-27 — Chaptered by Secretary of State. Chapter 650, Statutes of 2026.
Bill type
bill
Last updated
—

Subjects

Sponsors

  • Caballeroauthor

Committees

Not provided by source.

Action timeline

Newest first

  1. 2026-09-27

    Chaptered by Secretary of State. Chapter 650, Statutes of 2026.

    became-law

  2. 2026-09-27

    Approved by the Governor.

    executive-signature

  3. 2026-08-27

    Enrolled and presented to the Governor at 4:30 p.m.

    executive-receipt

  4. 2026-08-19

    Read third time. Passed. Ordered to the Senate.

    passage,reading-1,reading-3

  5. 2026-08-19

    (Corrected August 21).

  6. 2026-08-19

    In Senate. Ordered to engrossing and enrolling.

    committee-passage

  7. 2026-08-19

    Read third time. Passed. (Ayes 78. Noes 0. Page 6261.) Ordered to the Senate.

    passage,reading-1,reading-3

  8. 2026-08-04

    From inactive file.

  9. 2026-08-04

    Ordered to third reading.

    reading-1,reading-3

  10. 2026-08-03

    Notice of intention to remove from inactive file given by Assembly Member Aguiar-Curry.

  11. 2025-09-10

    Ordered to inactive file on request of Assembly Member Aguiar-Curry.

  12. 2025-09-02

    Read second time. Ordered to third reading.

    reading-1,reading-2,reading-3

  13. 2025-08-29

    From committee: Do pass. (Ayes 15. Noes 0.) (August 29).

    committee-passage,committee-passage-favorable

  14. 2025-07-16

    July 16 set for first hearing. Placed on APPR. suspense file.

  15. 2025-07-01

    From committee: Do pass and re-refer to Com. on APPR. with recommendation: To consent calendar. (Ayes 12. Noes 0.) (July 1). Re-referred to Com. on APPR.

    committee-passage,committee-passage-favorable,referral-committee

  16. 2025-06-05

    Referred to Com. on W. P., & W.

    referral-committee

  17. 2025-05-29

    In Assembly. Read first time. Held at Desk.

    reading-1

  18. 2025-05-29

    Read third time. Passed. (Ayes 38. Noes 0. Page 1328.) Ordered to the Assembly.

    passage,reading-1,reading-3

  19. 2025-05-27

    Ordered to special consent calendar.

  20. 2025-05-23

    Read second time. Ordered to third reading.

    reading-1,reading-2,reading-3

  21. 2025-05-23

    From committee: Do pass. (Ayes 6. Noes 0. Page 1206.) (May 23).

    committee-passage,committee-passage-favorable

  22. 2025-05-16

    Set for hearing May 23.

  23. 2025-05-05

    May 5 hearing: Placed on APPR. suspense file.

  24. 2025-04-29

    Set for hearing May 5.

  25. 2025-04-24

    Read second time and amended. Re-referred to Com. on APPR.

    amendment-passage,reading-1,reading-2,referral-committee

  26. 2025-04-23

    From committee: Do pass as amended and re-refer to Com. on APPR. with recommendation: To consent calendar. (Ayes 6. Noes 0. Page 839.) (April 22).

    amendment-passage,committee-passage,committee-passage-favorable,referral-committee

  27. 2025-04-04

    Set for hearing April 22.

  28. 2025-04-02

    Re-referred to Com. on N.R. & W.

    referral-committee

  29. 2025-03-24

    From committee with author's amendments. Read second time and amended. Re-referred to Com. on RLS.

    amendment-passage,committee-passage,reading-1,reading-2,referral-committee

  30. 2025-03-05

    Referred to Com. on RLS.

    referral-committee

  31. 2025-02-21

    From printer. May be acted upon on or after March 23.

  32. 2025-02-20

    Introduced. Read first time. To Com. on RLS. for assignment. To print.

    introduction,reading-1,referral-committee

Versions

  • 02/20/25 - Introduced — 2025-02-20Compare
  • 03/24/25 - Amended Senate — 2025-03-24Compare
  • 04/24/25 - Amended Senate — 2025-04-24Compare
  • 08/20/26 - Enrolled — 2026-08-20Compare
  • 09/27/26 - Chaptered — 2026-09-27Compare
  • SB599Compare
  • (document, no version)Compare

Documents

Votes

  • Do pass as amended, but first amend, and re-refer to the Committee on [Appropriations] with the recommendation: To Consent Calendar

    2025-04-22 · pass · 6-0

    Member-level votes (7)
    • Allen: yes
    • Stern: yes
    • Limón: yes
    • Grove: yes
    • Laird: yes
    • Seyarto: yes
    • Hurtado: other

  • Placed on suspense file

    2025-05-05 · pass · 7-0

    Member-level votes (7)
    • Richardson: yes
    • Grayson: yes
    • Seyarto: yes
    • Caballero: yes
    • Dahle: yes
    • Cabaldon: yes
    • Wahab: yes

  • Do pass

    2025-05-23 · pass · 6-0

    Member-level votes (7)
    • Caballero: yes
    • Seyarto: yes
    • Wahab: yes
    • Cabaldon: yes
    • Richardson: yes
    • Grayson: yes
    • Dahle: other

  • Special Consent

    2025-05-29 · pass · 38-0

    Member-level votes (40)
    • Smallwood-Cuevas: yes
    • Grayson: yes
    • Grove: yes
    • Dahle: yes
    • Rubio: yes
    • Jones: yes
    • Umberg: yes
    • Weber Pierson: yes
    • Wiener: yes
    • Stern: yes
    • Padilla: yes
    • Arreguín: yes
    • Caballero: yes
    • Pérez: yes
    • McNerney: yes
    • Gonzalez: yes
    • Durazo: yes
    • Cortese: yes
    • Archuleta: yes
    • Blakespear: yes
    • Laird: yes
    • Strickland: yes
    • Choi: yes
    • Valladares: yes
    • McGuire: yes
    • Niello: yes
    • Allen: yes
    • Richardson: yes
    • Hurtado: yes
    • Cervantes: yes
    • Seyarto: yes
    • Menjivar: yes
    • Wahab: yes
    • Becker: yes
    • Alvarado-Gil: yes
    • Ochoa Bogh: yes
    • Ashby: yes
    • Cabaldon: yes
    • Limón: other
    • Reyes: other

  • Do pass and be re-referred to the Committee on [Appropriations] with recommendation: To Consent Calendar

    2025-07-01 · pass · 12-0

    Member-level votes (13)
    • Jeff Gonzalez: yes
    • Caloza: yes
    • Bennett: yes
    • Alvarez: yes
    • Rogers: yes
    • Ávila Farías: yes
    • Hart: yes
    • Celeste Rodriguez: yes
    • Tangipa: yes
    • Papan: yes
    • Boerner: yes
    • Bains: yes
    • Macedo: other

  • Do pass.

    2025-08-29 · pass · 15-0

    Member-level votes (15)
    • Ta: yes
    • Elhawary: yes
    • Pellerin: yes
    • Fong: yes
    • Pacheco: yes
    • Tangipa: yes
    • Calderon: yes
    • Arambula: yes
    • Dixon: yes
    • Mark González: yes
    • Sanchez: yes
    • Wicks: yes
    • Caloza: yes
    • Ahrens: yes
    • Solache: yes

Related bills

No related bills recorded for this bill.

Official source

http://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260SB599

Attribution

Data from openstates_api_sync, retrieved 2026-09-30T15:54:55.732407Z

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