DATE: Saturday, November 8, 1997            TAG: 9711080318

SECTION: LOCAL                   PAGE: B3   EDITION: FINAL 

SOURCE: BY STEVE STONE, STAFF WRITER 

                                            LENGTH:   90 lines

EL NINO AN UNLIKELY PLAYER IN SHAPING VIRGINIA'S WEATHER

Call it the El Nino Factor - or fiction.

Mention the winter to come and someone is bound to say Virginia is assured an Arctic gift of snow and cold; others will as quickly say Hampton Roads can expect to luxuriate in a southerly flow of insulating warmth. All thanks to El Nino.

The mother of all weather systems has become a cause cliche, blamed for everything short of the recent stock market plunge.

Truth is, El Nino - a major warming of Pacific Ocean currents off Peru that has a huge effect on global weather patterns - is hard to link to local meteorological events. And history provides no evidence of an El Nino trend for winters in Hampton Roads.

``There's no indication whatsoever that there is any useful predictability to be derived from El Nino'' in forecasting what winter holds in store for Virginia, said Jerry Stenger, research coordinator for the Virginia State Climatologist's office.

Still, folks are wondering - as they do annually - what the winter to come will bring. And even though the official National Weather Service outlook offers little in the way of excitement, El Nino has provided a tantalizing bit of spice for others who cook up seasonal forecasts.

``We've had a lot of people ask us this year how El Nino conditions are likely to affect our upcoming winter,'' said Stenger, who has done an extensive study of winter weather in Virginia during past strong El Ninos. But he found no relationship between it and rainfall, temperature or snowfall. ``As far as Virginia goes, it's not a very good predictive tool.''

Dewey Walston, a meteorologist at the Weather Service forecast office in Sterling, agrees. Periods when Pacific currents are cooler than normal - the much less heralded La Nina - actually seem to correlate more closely with significant winter weather events in Virginia. ``La Nina is a lot scarier than El Nino around here,'' Walston said.

An analysis by the National Oceanic and Atmospheric Administration of weather patterns over North America during previous strong El Nino years reaches the same general conclusion. Although it shows there is a tendency for a slightly wetter winter along the East Coast - and only a narrow corridor of coastline at that - overall, the entire mid-Atlantic region is largely unaffected in terms of precipitation or temperature.

So, what will happen this winter? Stenger has no idea. ``So far, we haven't gotten any really good clues as to what's lurking for us this winter,'' he said. ``Last year we saw some significant changes in the jet stream that led us to believe we might be in for a relatively uneventful winter - which it was.''

When the jet stream steers north of the mid-Atlantic region, that generally assures Virginia and North Carolina a warmer winter. Wet, perhaps, but usually lacking much, if any, snow.

But if the jet stream takes a more southerly track, that increases the likelihood for a colder winter with a greater threat of snow.

And place the jet stream on a track where it dips to the Gulf of Mexico and then heads north along the East Coast and you have the best setup for snow - cold air rushing down from Canada running into moist air from the South.

``At this point, however, we have not seen any development where the jet stream is locked into a persistent pattern,'' Stenger said.

Others, however, say they know exactly what is in store.

``Winter storms worst ever!'' screamed the supermarket tabloid Sun last month. It promised that snow would ``blast'' the South, burying towns under 10 feet of white stuff.

``Americans will be battered by hail the size of bowling balls, incredibly huge lightning bolts will explode houses into splinters, stranded air travelers will freeze to death in blacked-out airports and San Francisco will be split in half by a monster earthquake.''

Now, back to reality.

The Old Farmer's Almanac paints a picture of a rather dull winter for the middle Atlantic coast. While it foretells a colder than normal November and December, 1998 opens with four months of above-normal temperatures.

Snow is forecast for Dec. 10-13, Dec. 17-20, Jan. 15-17 and Jan. 23-26 - but only in western parts of Virginia, with rain to the east.

After a frosty Christmas holiday, the Blum's Farmer's and Planter's Almanac calls for the year to end with a blast. Snow is twice forecast in February, on the 8th to 11th and again on the 20th to 23rd.

The Farmer's Almanac (no kin to the ``Old'' version above) offers the most eventful winter outlook. December offers an intensifying coastal storm on the 16th-19th that ``delivers high winds and heavy precipitation,'' followed by frost. Then, as the month ends, a strengthening storm from the Southern Plains ``intensifies as it moves to the mid-Atlantic states, bringing possible heavy snowfall with up to 4 inches to 8 inches, then fair and cold in time for 1998.''

Finally, there's the official, if nowhere near as exciting or specific, version from the National Weather Service. The Climate Prediction Center's computers are calling for near normal temperatures for Virginia and North Carolina this winter with normal precipitation over most of Virginia. Southeast Virginia and much of North Carolina have a 5 percent probability of more precipitation than normal. And there's no mention of bowling ball-sized hailstones.

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