One small squiggle on a map could mean one giant leap for Santa Fe weather warnings.

The National Weather Service will launch a reconfigured zone map of New Mexico at 3 p.m. today. The new map will better reflect terrain and climatology — and it includes a separate forecasting area for Santa Fe Metro.

The goal is to improve the accuracy of warnings issued for Santa Fe and other communities and regions across the state, said Daniel Porter, a senior meteorologist at the service in Albuquerque.

"In the past, let's say we had snows coming in to Angel Fire and Eagle Nest," Porter said. "Those areas were all grouped together with Santa Fe and the Sangre de Cristos, and so we'd have to issue a winter storm warning for all of them, even though we knew Santa Fe wouldn't get snow."

On the new map, the Sangre de Cristo Mountains have been split into four zones, and Santa Fe has been split off from them — which means if the service predicts snow for the Santa Fe Metro zone, it will actually mean it.

"Santa Fe, I would say, is probably going to be the most affected by this change," Porter said. "We've made lots of tweaks and retooled a lot of things. Santa Fe Metro will be more in line with the lower elevation sites now, like other towns in the Rio Grande Valley."

The new map likely won't change day-to-day forecasting as much as it will alter things like weather warnings for snowstorms, wind or flooding.

"Our warnings will be more detailed, and we're not going to issue warnings for big blocks of areas anymore," Porter said.

Santa Fe isn't the only spot that was subject to inaccurate warnings from the old zone maps. Farmington would often get warnings for snowstorms in southern Colorado because of its large zone, even when the service knew the storms were unlikely to reach the city, Porter said.

"Our new zone for Raton will also help a lot — that zone used to stretch to Las Vegas," Porter said. "Las Vegas would get winter snow warnings because it was grouped with Raton, and people would call us, looking up at the sky, telling us it was all clear."

Overall, the map has grown from 22 zones based somewhat along county lines into 40 zones based more on geography.

A group of forecasters and management in the Albuquerque office has been working on the change for about a year. But other than a few software tweaks and taking time to send out a lot of notifications, the change didn't cost the service much of anything, Porter said.

"A lot of this work we did on our regular shifts, when it was slow," Porter said. "It's just a lot of tweaks, but we hope it will have a big impact on the products we provide."

Contact Sue Vorenberg at svorenberg@sfnewmexican.com.

THE NEW ZONES

To see the new zones and how the mapping has changed, visit www.srh.noaa.gov/abq/zones/2009publiczones.php.