WHO TURNED OFF THE HEAT? SUMMER COOLEST IN YEARS.

Byline: Phillip W. Browne Staff Writer

Despite a few triple-digit scorchers recently, the summer of 1999 will take its place in the history books as the coolest since at least 1990 - by a downright frosty 4 degrees, forecasters said Thursday.

The average daily temperature at the Los Angeles Civic Center between June and August hovered at a mild 70 degrees - a significant drop from the average 74 degrees this decade, the National Weather Service said.

And temperatures for June, July and August have not been as low since 1908, 1944 and 1914, respectively, forecasters said.

``This is really unusual. It's been quite a bit cooler. A 3-1/2-(degree) to 4-degree drop is really very significant,'' said NWS meteorologist Gary Ryan.

Exactly why Los Angeles is shivering through a record-cool summer is not clear enough for forecasters to reach a consensus, but each said that the global weather gal, La Nina, plays a role.

Regardless, don't expect it to heat up for Labor Day, the traditional end of summer. ``It's going to be cooler, but the drawback is we may not see that much of the sun,'' Ryan said.

Beachgoers should bring a sweater, as temperatures are expected to dip into the 70s on Saturday along the shore and reach into the 80s the rest of the weekend, Ryan said.

A thick marine layer is expected to linger throughout the weekend, mostly in the morning hours. The haze is expected to linger all day Saturday, but it could burn off in the afternoons Sunday and Monday, Ryan said. Temperatures could creep into the low 90s in the San Fernando Valley, he said.

Cool time, summer in the city

Dani Madrid and Cheryl Hanks, both 18-year-old Woodland Hills residents, said they are surprised that the summer of 1999 is cooler than normal.

``It seems like it's been hot to me. But I guess it hasn't been as hot as before. I haven't needed the air conditioning as much,'' said Madrid, sitting outside a Woodland Hills deli.

``You know, I don't think I've sweated that much this summer, so I guess it has been cooler,'' Hanks said. ``I remember days a few years ago walking around school just wanting to pass out.''

The 1999 summer is a far cry from the devil-hot months in the early '80s - the hottest ever on record. Temperatures during the three-month periods in 1981, 1983 and 1985 reached about 10 degrees hotter on average compared with this year.

While Weather Service forecasters said there is no simple reason for the drop, other meteorology experts blame La Nina, which has caused a pool of cooler-than-normal water to bump up against the West Coast. La Nina essentially acts as a pump that sends cold air into Los Angeles, experts said.

``Because of La Nina, the Pacific has been cooler by about 3 degrees compared to its normal average 67 degrees,'' said Larry Riddle, a climatologist for the Scripps Institute in San Diego. ``The temperature of the air above the water, which is the air that comes on shore, is about 3 degrees higher than the water, so by default the air temperature will be cooler.''

The heavy, cold air from the Pacific flows into Los Angeles and heats up when it gets to the desert, Riddle said. When it heats up, the air rises, opening up pockets for more cool air to flow into the region.

Mark Tobin, a meteorologist for AccuWeather in Pennsylvania, said La Nina also is responsible for the heavy storms in the Pacific Northwest that pushed the unusual rainfall into Los Angeles in June.

``The cold La Nina air changed the pattern of the jet stream, pushing storms further south,'' Tobin said. ``We had talked about this summer being cooler, but I didn't know it would set records like this.''

Los Angeles residents had to turn up the heat and get out the woolens in early June when record rainfall fell, snow peppered Mt. Wilson in the Angeles National Forest, hail pelted Santa Clarita and a funnel cloud hovered over San Pedro. NWS experts could not remember the last time mercurial weather hit` in June.

Not only was the heat down this summer, but so was electrical usage.

An average summer day in Los Angeles usually pulls about 4,500 megawatts with the extra burden of whizzing air conditioners, said Darlene Battle, spokeswoman for the Los Angeles Department of Water and Power.

The average megawatt usage Thursday was 3,810, Battle said.

``We have definitely seen a reduction,'' Battle said. ``It's a huge difference from the El Nino summer last year when in September we reached our all-time peak at 5,650 megawatts.

``People must be much cooler this year,'' she said.

The travel industry has neither benefited nor lost from the cooling trend, maintaining an average of 7.5 million visitors to Los Angeles this summer.

``It's the same amount we've had the past few years. The growth has been flat - same as the past couple of years,'' said Carol Martinez, director of media relations for the Los Angeles Visitors and Conventions Bureau.

``Los Angeles has never really been a weather destination. People come here for the attractions. A 4-degree change is not going to keep people away,'' Martinez said.

CAPTION(S):

photo, chart

Photo: Tracy Greenberg, 11, shivers under the water spray at Will Rogers State Beach on an overcast Thursday morning. The thick marine layer is expected to linger throughout the weekend, especially in the mornings, and beach temperatures will stay in the 70s and 80s.

Charlotte Schmid-Maybach/Staff Photographer

Chart: Cold summer

Los Angeles historical average temperatures for summer months