The "short" session of the Virginia General Assembly will convene at noon on Wednesday, and it will be unusually busy. The Commonwealth's constitution, as revised in 1970, provides for a 60-day session in even-numbered years and a 30- day session in odd-numbered years. The General Assembly has the constitutional authority to extend each session up to an additional 30 days by a two-thirds vote of each house.

The leadership has agreed to recommend to extend the 1983 session by 16 days for a total 46 days. Ever since the Commonwealth went to annual sessions, the "short" sessions have been extended for additional 15 or 16 days. Moreover, the number and nature of bills considered in the "short" sessions seem to increase and become more complex.

Some members of the General Assembly, recognizing that Virginia either will have to remove the constitutional limitations to its legislative sessions or find a way to limit the number and type of bills that can be considered in the "short" sessions, proposed a constitutional amendment to provide a means for such limits. This proposal was looked upon by some as a choice between a citizen legislature, such as we have enjoyed since the 17th century, or a professional legislature, such as those in New York and California.

The Post editorially opposed the proposed amendment, as did other newspapers throughout the state, and it was resoundingly defeated in the November elections. So what can we expect for the next two months?

To start with, because of high unemployment and unfavorable business conditions, state revenues are projected to be $305 million less than had been projected when the biennial budget was adopted in 1982.

Last fall, Gov. Charles Robb ordered a 5 percent cut for selected state agencies. Higher education was affected, but aid to localities, including public education, was exempted. At that time, the shortfall was estimated to be approximately $100 million. The cuts now will very likely be across the board and deeper.

Never before in modern times has a Virginia General Assembly been faced with such a problem. Add to that the fact that, for the first time since going to annual sessions, the members of the House of Delegates have just been elected in a special court-ordered election, with campaign promises to be delivered. This is further compounded by the entire legislature's being up for election in 1983. Legislators typically consider it important to have a record on which to run. Short sessions in the past have been hectic. Look for this one to be hectic and chaotic.

Other issues that will be addressed in approximately 1,600 bills:

Drinking Age--Look for the legal drinking age to be raised. The pressure is to raise it to 21, although some legislators are expected to propose that it be increased in steps that would take three years to make the legal age 21 for both on-sale and off-sale drinking.

Conflict of Interest--The state attorney general has drafted a tougher conflict-of-interest bill, structured in a way to make it more understandable and accessible to local and state elected and appointed officials. 10 4 Insanity Plea--It is expected that one or more bills will be introduced to provide for a finding of guilty but mentally ill in criminal cases--a sequel to the Hinckley verdict.

The Robb Anti-Crime Program includes multi-jurisdiction grand juries; wiretap information control; relaxing the exclusionary rule; prohibiting the sale of armor-piercing ammunition; and other important anti-crime measures. The speaker has already indicated opposition to part of the program, and the American Civil Liberties Union has also raised objections.

Uranium Mining--In 1982, the legislature enacted a moratorium on uranium mining until July 1, 1983. A study commission is expected to recommend extending the moratorium for another year for further study.

Interbasin Transfer of Water-- This has been under study for years. Tidewater--Virginia Beach, in particular--is pressing for a solution to its fresh-water shortage. The pros and cons are complex and emotional.

Coal Slurry Pipeline--Vepco is seeking statutory authority to exercise eminent domain in the construction of a coal slurry pipeline. The railroads are bitterly opposed. The cost of the lobbying effort on both sides will surpass anything Virginia has ever seen.

Yes, Virginia, we do have problems. They will all surface in this election year 1983, come Wednesday at noon.