The board of directors of the Corporation for Public Broadcasting has agreed to meet tomorrow to discuss a request from National Public Radio for $1.3 million to alleviate an anticipated shortfall in private grant revenues.

In a letter sent last week to CPB President Edward J. Pfister, NPR President Douglas Bennet outlined the potential problem and formally requested a $1.3 million supplementary grant to meet the goals of the 1985 fiscal year budget and sustain current program commitments.

"It is highly likely that we will achieve our goal of $3.7 million in grants," said Deborah Weingrad, spokeswoman for NPR. "The $1.3 million is the difference between our best estimate in what we will be able to recognize as income in fiscal 1985 and what we have in hand now, $2.5 million. The grant cycle is a yearlong cycle but the later it comes in the year, the less impact it can have on the current operating budget. It is a prudent step to make the judgment about the shortfall at this time."

In response to the request, which was initially made by NPR board chairman Donald Mullally at a CPB board meeting two weeks ago, Pfister called a meeting of his board and alerted Sen. Barry Goldwater (R-Ariz.), the chairman of the senate communications subcommittee, and Rep. John Dingell (D-Mich.), chairman of the House Committee on Energy and Commerce, about the matter.

In his letter to Goldwater, Pfister said, "NPR has requested that CPB increase by $1.3 million its contribution toward existing FY 1985 program service contracts. Otherwise, NPR represents that it will be forced to undertake budget adjustments which, over the long term, could place at risk the viability of certain NPR services."

CPB, the federally funded private corporation that distributes federal funds for public broadcasting, serves as an important financial lifeline for the radio network. In fiscal 1983, NPR suffered a $7.4 million deficit and near bankruptcy, which was avoided by a loan from CPB. NPR has met the repayment schedule for that loan. Federal appropriations account for half of NPR's budget and the rest is provided by foundation grants, $1.5 million in membership fees from its stations and individual contributions.

For fiscal 1985, CPB gave NPR $10.3 million instead of an anticipated $10.6 million, a difference of $330,000, among other losses and new expenses, that led the NPR board last month to tighten its $22 million budget by $686,000. The existing programming contracts with CPB are not an issue in this shortfall.

In a letter sent Tuesday to Dingell, Pfister said, "The NPR current dilemma is due entirely to NPR's overly ambitious expectation of nonCPB grant revenue. CPB's decision regarding the supplemental funds of $330,000 and $950,000 is not related in any way to NPR's current dilemma."

CPB is expected to discuss the matter at 5 p.m. tomorrow by telephone. Weingrad said she could not comment on the impact on NPR if the request was not met. "It is in negotiation," she said.