By Boldizsar Gyori

BUDAPEST, Aug 23 (Reuters) -Central-European currencies firmed slightly on Friday as investors waited for a key speech by U.S. Federal Reserve Chairman Jerome Powell scheduled for later today after U.S. economic data gave the green light for policy-easing.

Investors were also in a wait-and-see mode ahead of an interest-rate decision by Hungary's central bank scheduled for next Tuesday.

Hungary's forint EURHUF= was at 393.3 by 0758 GMT in rangebound trading.

"I expect the forint to trade sideways until next Tuesday's rate-decision," a local FX-trader said.

"We're also waiting for Powell's speech, although don't expect a surprise, despite voices that suggest the FED will start by a 0.50 bps cut, and not a 0.25. If this will be the case, that will be supportive for the forint."

Central bank officials from around the world have gathered in Jackson Hole, Wyoming, for the annual Economic Symposium, where investors will be focused on the timing and extent of the FED's policy easing.

A readout of the FED'S July meeting showed a "vast majority" of policymakers agreed the policy easing likely would begin next month.

Elsewhere in the region, the Czech crown EURCZK= traded at 25.06.

Czech utility CEZ dropped over 2% on Thursday after the Finance Ministry said it would drop a previously mooted idea to end a windfall tax on energy companies and banks next year, which would be one year earlier than the current law states.

CEZ is by far the largest payer of the tax, and has said it may pay around 27-34 billion crowns this year. The stock was down 0.5% after opening on Friday.

The Polish zloty EURPLN= also remained in range, trading at 4.278 to the common currency.

"The zloty is slightly stronger, basically we are trading in a range... (it is ) flow driven," a Warsaw-based currency trader said.

Meanwhile, shares in Polish supermarket chain Dino DNP.WA fell 13% after its second quarter results missed market expectations, with the Warsaw exchange index .WIG20 trading sideways.

Written by Boldizsar Gyori in Budapest; additional reporting by Jan Lopatka in Prague and Alan Charlish in Warsaw; Editing by Sharon Singleton

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