(let's try this again, for some reason my original reply didn't get through...)
Unless it's being discussed at higher levels of management than I'm privy to (very possible) there is no specific schedule for HD local news on channel 4. However, technical work is being done towards going HD in a reasonable amount of time. (I'm not prepared to define "reasonable"

) HD was considered in set design, and some gear has been purchased with HD in mind. (for a trivial example, the floor monitors and all the monitors you see on the air are HD, though of course showing a SD image while on air)
There is an ENORMOUS amount of work (read that, loosening of purse strings) involved in doing HD local news. Things you need to simply get HD studio cameras on the air:
- HD cameras
- (teleprompters, intercom equipment, pedestals, tally lights to match)
- HD production control switcher
- HD monitors for the control room
- HD video distribution equipment
- SD=>HD upconverters for those sources that *aren't* HD yet
- HD=>SD downconverters for those destinations that aren't HD yet (feeds to other stations, monitors buried in the set, etc.)
- HD master control switcher
- HD monitors for master control
- more HD video distribution equipment
- HD routing switcher
- racks & similar hardware to hold all this gear
- a plan to get all this done without taking the station off the air or killing the ability to do a newscast
- plastic surgery for the talent (just kidding, I hope)
(this assuming the station already has the transmission equipment to pass through HD from the network)
To do the news stories in HD you also have to have:
- HD field cameras
- Bigger storage cards (assuming you're doing solid-state recording) or more tapes or blank DVDs (if you're recording to tape or DVD. Channel 4 uses solid-state recording on cards that resemble laptop modems.)
- HD editing stations
- HD playout servers
- More hard disk space
- HD encoders/decoders for microwave trucks and receive sites
- more monitors & routers
When channel 5 went HD for their local newscasts, their GM told the Tennessean it cost them $10 million. I think that figure is a bit high but I don't think it's entirely out of touch with reality.