For LI, rain comes in name only

It rained last night in Upton, the home of Brookhaven National Laboratory, where the wildfire that ravaged more than 1,000 acres of Long Island pine barrens is believed to have started on Monday.

That rainfall, forecasters at the National Weather Service in Upton said, was more a technicality than anything -- since it rained just five-hundredths of an inch overnight Wednesday into Thursday.

"Just a trace," meteorologist Mike Layer told Newsday, explaining that the "rain" was more like a morning dew.

In fact, though scattered showers are possible Thursday in Nassau and Suffolk, with forecasts calling for a 30 percent chance of rain in Manorville and Ridge, where the wildfire burned 1,124 acres on earlier in the week, authorities said the real need is for some significant rainfall -- and none is in our immediate future.

"Any little bit helps," Layer said. But, he said Thursday, "Overall, we're going to need a decent amount of rain to get rid of the fire threat."

And, he said, even with showers possible Thursday and again on Saturday and Sunday -- and with a potential rain-carrying system brewing in the Rocky Mountains that could arrive by the middle of next week -- nothing indicates a game-changing rain.

Records show Long Island has had the driest March on record in Islip, with just 0.99 inches of rain. The previous record was 1.08 inches in 2006. Currently, the Island is mired in the second-driest April on record with just 0.31 inches of rain so far. The driest was 1991, when 0.02 inches fell in April.

Records have been kept in Islip since 1984. Precipitation records for Brookhaven National Lab, kept since 1949, show that the driest March on record also was 2006 -- with 0.89 inches. The driest April was 2010, with 0.74 inches. The average precipitation for March is 4.78 inches, for April 4.27.

Though the weather service canceled a red flag warning on Tuesday -- such warnings are issued when conditions are conducive to spawning wildfires, brush fires and forest fires -- authorities said Thursday that Long Island is not out of the woods -- and might not be anytime soon.

The criteria required to issue a red flag warning -- or, a fire watch warning -- are sustained winds or frequent wind gusts greater than 25 mph, a relative humidity of less than 30 percent and rainfall of less than one-quarter inch in the previous three days.

Long Island had only light winds on Tuesday, Wednesday and Thursday, the only reason a red flag warning was not in effect, forecasters said.

Winds on Thursday are expected to be in the 11 to 15 mph range and in the 8 to 11 mph range on Friday, forecasters said.

"If we look out through the next week, there might be a weather system coming through the middle of next week," Layer said. A low-pressure system is originating off the Rockies, would cross the Plains, the Great Lakes region and move from east to northeast across Nassau and Suffolk no later than Wednesday, he said.

But will it bring rain?

"It's a possibility," Layer said. "A possibility."