Vincent Gray and Natwar Gandhi are reveling in the city’s financial good times. (John McDonnell/The Washington Post)

Updated 5:15 p.m. with details from Gandhi and Gray letters

The District government is expected to take in roughly $600 million more in the coming five years than previously anticipated, including an addition $85.9 million in the current budget year, setting up another huge surplus.

Chief Financial Officer Natwar M. Gandhi said in a letter to Mayor Vincent C. Gray, and D.C. Council Chairman Phil Mendelson (D) that roughly half of the upgrades could be attributed to stronger-tan-expected income tax collections, evidence of a growing population and a city economy that has remained resilient in the face of federal spending reductions.

The current-year upgrade will almost certainly stay in the bank for now. Gray spokesman Pedro Ribeiro said the mayor has no plans to submit a supplemental spending request to the council for 2013 revenue, now expected to total $6.14 billion. That means, come final audit time next February, the city could be looking at another record windfall — approaching the $417 million reported for 2012.

But the coming budget year, which starts Oct. 1, is a different story. At least a portion of the additional $92.3 million estimated for fiscal 2014 could be obligated when the council takes its second and final vote on budget legislation Thursday.

Mendelson said Monday that he would present a proposal for spending up to $50 million of the new revenue at Wednesday’s council meeting. He declined to detail which programs or proposals might be funded.

In his initial budget request, submitted back in April, Gray included a “contingency priority list” of programs to be funded by future revenue upgrades. They included expansion of early childhood education, grants for senior programs, school-based mental health programs, commercial property tax reduction and more.

In a Monday afternoon letter to Mendelson, Gray laid out a revised list of priorities for the first $50 million in additional spending. Early childhood education ($11 million), senior grants ($5.8 million) and arts funding ($7 million) remain on the list. But Gray is adding a $23 million suggestion: A one-time funding boost for public schools, divided between the D.C. Public Schools system and charter schools.