From his office in Silver Spring, Maryland, the director of the National Weather Service closely monitored the arrival and development of Thursday’s snowstorm as it affected Long Island.

In a tweet, Louis W. Uccellini praised his weather service team for such an on-target forecast — made days in advance, also remarking: “Wish I could be there.”

That’s not just because he’s been smitten with snow since he was a toddler. It’s also because, as a Long Island native, it was snow around his Bethpage home that first caught his eye.

The day before Thursday’s storm, Uccellini outlined the scenario, noting the expected fast switch from mixed precipitation to all snow, with “very heavy snowfall” for the morning rush.

Indeed, the “threat” for the Island had been predicted as far back as Sunday, he said. And forecast tools since Monday had been pointing to the potential for thunder snow — thunder and lightning that come with snow instead of rain — which, sure enough, arrived right on cue.

Since 2013, Uccellini, 67, has been director of the weather service, which is charged with forecasting such events with an eye to keeping people and property safe.

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He spoke with Newsday recently, shedding some light on his career choice and giving his take on “the spiritual aspect” of snow.

Q. What features of Long Island make for challenging snowstorm forecasting?

A. First, Long Island is perched right next to the ocean, “moist and relatively warm, so any slight deviation in track of the storm and slight weakness in the cold air pattern allows warm air to come back in,” he said, “meaning precipitation events could be warm events.” That, of course, means rain, not snow.

Also, New England, an especially cold area of the country, is just to the north. Having “warmer waters to the south and colder air to the north” sets up a “significant temperature gradient,” leading to a sharp cutoff to the precipitation shield along the north border and a very sharp rain-snow line. The temperature gradient is also a reason for the Long Island area’s “intense winds that accompany the coastal storms — rain or snow — increasing the impact of these storms.”

Q. How is it that some snow forecasts are pretty much spot on, while others carry uncertainty right up to the day before?

A. For reasons yet to be determined, “some storms are more predictable than others,” Uccellini said. With last year’s January blizzard, “there was consistency in numerical predictions from run to run” six, seven, eight days in advance, he said. That remained the case even as the storm was approaching Long Island, where the Northeast Regional Climate Center says it dropped 23.7 inches of snow at Long Island MacArthur Airport in Ronkonkoma.

Of course, he said, there are also times when “model forecasts don’t line up with that kind of agreement days in advance.” He points to the blizzard of January 2015, which was “especially difficult to pin down for New York City and Long Island, even 24 hours in advance.” That was related to the “sharp western boundary between heavy snow and light snow, which lined up right over New York City.”

That time, MacArthur Airport saw 24.9 inches, while Central Park recorded 9.8 inches, which was much less than what had been forecast.

Q. The lesson learned from that 2015 blizzard?

A. “We didn’t communicate the uncertainty well enough earlier on,” he said, so moving forward the practice has been to emphasize “how and where things could change with major consequences for where and when the heaviest snowfall will occur.”

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That’s with an eye to helping “people understand the consequences of a shift in a forecast where 20- to 25-mile differences in the snow/no snow line can result in major differences in exactly where the heavy snow will occur.”

Q. What are the major tools/resources for forecasting snowstorms?

A. He points to “sophisticated numerical weather models that are fed data on the oceans and atmosphere from around the globe” as becoming “an essential component.”

And, “global satellite observing systems have become the backbone of the global data fed into the models, along with other data sets like observation balloons launched twice a day from stations around the globe and, increasingly, data from commercial aircraft.”

He said a forecast for Long Island, say, three to seven days in advance, “depends on the observations over Asia, over the Pacific, over the North Pole and at the equator,” and not just at the surface but also at varying levels of the ocean and atmosphere.

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Supercomputers are a further component, he said, with “a big boost” last year in capacity for the weather service, that now allows for running models at a higher resolution. That leads to “better representation of all the physical process that contribute to extreme weather events, like nor’easters.”

Q. Many people see snow as an annoyance. What’s its appeal to you, and how did it set you on the path to your career?

A. “It’s just something, an amazing thing to behold when it’s falling and how it changes the landscape in front of you,” said Uccellini, who holds bachelor’s, master’s and doctorate degrees from the University of Wisconsin.

Even as a toddler, he was smitten, he said, cajoling his parents for a look out the window when those flakes were falling.

Those snowstorms and tropical cyclones sparked his imagination, as well as his scientific curiosity, he said, regarding how snow is formed and why, say, New Jersey would sometimes get snow while Long Island ended up with rain.

Q. How about a nod to that spiritual element?

A. Uccellini pointed to two poems that he feels especially “capture the impact that snowstorms have on the human spirit.”

One is John Greenleaf Whittier’s “Snowbound,” which is excerpted in the introduction to “Northeast Snowstorms,” a two-volume reference guide that he co-authored with fellow snow enthusiast and former Long Islander Paul J. Kocin, a meteorologist with the Environmental Modeling Center, a part of the weather service, which is under the umbrella of the National Oceanic and Atmospheric Administration.

The second poem is Mary Oliver’s “Walking Home from Oak-Head,” which speaks of:

“waiting,

as for a gift,

for the snow to begin

which it does

at first casually,

then, irrepressibly.”

Q. How did you come to partner up with your co-author Paul Kocin?

A. Even though Kocin grew up in Syosset, not far from Uccellini’s home in Bethpage, the two didn’t meet until around 1980, when Kocin came to work as a contractor at NASA’s Goddard Space Flight Center’s Laboratory for Atmospheres.

That’s where Uccellini was heading up an analysis and modeling science team. One storm of special interest was a surprise system that hit the mid-Atlantic to New York City area on Presidents Day, Feb. 19, 1979.

Uccellini, who assigned Kocin to help with that storm’s analysis, recalls Kocin saying early on that, “I can’t believe you’re paying me to do this job. This is all I’ve wanted to do.” At which point, Uccellini said he realized “we were both cut from the same piece of cloth.”

They’re now at work on volume three of “Northeast Snowstorms.”