Weather radio to narrow broadcast focus
By ANDREW KRUEGER
JUNEAU EMPIRE
In a climate region where a few miles can mean a world of difference, the National Weather Service this week is implementing new forecast zones to provide more accurate weather predictions.
Starting Wednesday, the weather services Juneau Forecast Office will increase the number of public or land forecast zones to 13, up from nine. The number of marine forecast zones for inner channel waters will more than double, from five to 11.
There also will be more forecast zones for Gulf of Alaska outside waters from Dixon Entrance to Cape Suckling.
Because of the terrain in Southeast Alaska, theres a multitude of local weather effects, said Chris Maier, warning-coordination meteorologist at the Juneau Forecast Office. To truly capture those in a zone forecast, we needed smaller forecast areas.
For example, in the old system, Juneau was lumped with Hoonah and Angoon under a single zone forecast. Under the new system, each of the three communities will have its own forecast. The same holds true for Haines and Skagway, and for Sitka and Pelican.
On the water, one old zone that encompassed Lynn Canal and Glacier Bay has been broken into three zones in the new system. Stephens Passage, northern Chatham Strait, southern Chatham Strait and Frederick Sound will each have its own forecast, after being combined under the old system.
The smaller forecast zones are being facilitated by new technology at the Juneau Forecast Office.
Currently, forecasters examine computer weather models and type up zone forecasts usually twice a day.
With the new technology, the Interactive Forecast Preparation System, forecasters will as before be presented with model-based forecast maps on their computer screens. But drawing from their local experience, forecasters will be able to make adjustments on the map to account for local climate subtleties creating a forecaster-enhanced graphical forecast.
Once that is completed, a computer program will automatically create text forecasts for each of the new zones by reading the forecast map. Those text forecasts are issued to the public via weather radio, commercial media and the Internet.
Instead of looking at these tools and conjuring the forecast in our minds, were adjusting the map and letting the technology read the map and put into words what we have done, said Tom Ainsworth, meteorologist-in-charge at the Juneau Forecast Office.
The automation will allow for continually updated forecasts as conditions warrant.
Under the old system, forecasts were disseminated on a scheduled basis, Ainsworth said. Now, a forecast should always be current. If there needs to be a modification, well modify the map and well issue it quickly.
Graphical forecasts for a wide range of conditions including precipitation chances, temperatures, winds and waves will be available to the public on the Juneau Forecast Offices Web site, http://pajk.arh.noaa.gov.
Experimental graphical forecasts as well as more details on the new forecast zones are currently posted on the site.
Now there are different ways of literally seeing the forecast, Ainsworth said.
The changeover to graphical forecasts is a nationwide movement, and Juneau is the first forecast office in Alaska to make the switch. Anchorage and Fairbanks are expected to change to graphical forecasts in January.
Maier and Ainsworth said the weather service is seeking opinions on the new forecast zones. Contact information can be found on the Juneau Forecast Office Web site, or the office can be reached at 790-6800.
Andrew Krueger can be reached at akrueger@juneauempire.com.