Missouri school officials may have another month's wait before they know how much money they'll get next year in state aid.
Lawmakers have until May 9 to pass the budget for the 2014-15 state business year that begins July 1.
The House passed its version of the 2014-15 budget on March 27. The state Senate begins its committee hearings on that budget this week.
The House-passed budget includes a $122 million increase in the state aid formula for public education, but could increase that funding to $278 million - if the state's income is higher than the Republican-led House and Senate budget officials have estimated.
Democratic Gov. Jay Nixon's office predicted a better revenue picture than the Republicans, and Nixon's plan to fully fund the formula within two years is based partly on those higher income estimates.
The state's budget for elementary and secondary schools currently is $556 million below the funding level required by the formula lawmakers adopted in 2005.
The Missouri Constitution requires the governor to, "within thirty days after it convenes in each regular session, submit to the general assembly a budget for the ensuing appropriation period, containing the estimated available revenues of the state and a complete and itemized plan of proposed expenditures of the state and all its agencies, together with his recommendations of any laws necessary to provide revenues sufficient to meet the expenditures."
But the lawmakers actually write the budget - and they're free to take whatever they want from the governor's budget proposal, or ignore it and write their own plan.
The Senate's Appropriations Committee has been meeting with state department and agency heads since the beginning of the year, to get an idea of what their budget needs and requests were, and it begins holding public hearings on the House-passed bills at 1 p.m. Monday.
The Senate can adopt the House-passed plan or amend it.
Usually, senators keep some of the House ideas and substitute their own on other parts of the budget - and the final set of bills is written by a conference committee of House and Senate members.
As with all bills, the Constitution requires both chambers to agree on the same language - in budget bills, the same numbers - before a bill can be "truly agreed and finally passed" to the governor, who can veto individual budget lines or entire bills, but cannot add to or otherwise modify, what the Legislature passes.
The Associated Press contributed information used in this story.