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Category: Science

  • About that ‘White Christmas’ dream, and other snowy thoughts at the solstice

    About that ‘White Christmas’ dream, and other snowy thoughts at the solstice

    With a predictable precision that may forever elude meteorology, at 10:03 a.m. Philadelphia time Sunday, the sun will beam its most direct light of the year on the Tropic of Capricorn and the astronomical winter will begin in the Northern Hemisphere.

    Sunday indeed is going to be the shortest day of 2025, with just over nine hours and 23 minutes between sunrise and sunset.

    On the bright side for those who have about had their quotas of premature darkness, the day length would be a mere one second shorter than Saturday’s, and on Monday, we gain two more seconds. On the dark side, Sunday’s sunset is a full three minutes earlier than that of Dec. 12. (And don’t ask about sunrise.)

    Plus, in two weeks the night skies will become considerably brighter with the rising of the last of four consecutive “super moons,” which will peak on Jan. 3.

    Whether the brightness would be enhanced by snow cover is another matter: Meteorology has a long way to go to catch up to astronomy in terms of predictability.

    In the early going, Philly is more than halfway to last winter — with 4.2 inches of snow, vs. 8.1 for the entire winter of 2024-25.

    In the short term, this is a peak time for a perennial question.

    Is it going to be a white Christmas?

    “No” almost always is a safe answer in Philly, and all along the Northeast Corridor from Washington to Boston. And “no” it is this year, says Bob Larsen, senior meteorologist at AccuWeather Inc.

    With a white Christmas defined as an inch of snow on the ground at Philadelphia International Airport on Dec. 25, the National Oceanic and Atmospheric Administration officially posts about a 1-in-10 chance that it will happen in any given year in Philly.

    So why the fascination? Blame Irving Berlin, composer of “White Christmas,” and Bing Crosby, who crooned the most famous version, but probably a bigger impetus was the poem “A Visit from St. Nicholas,” published in 1823 and credited to Clement Moore.

    The poem cast Santa Claus as personally delivering gifts via his sleigh. This predated Amazon Prime. That pretty well cemented the Christmas/snow relationship.

    Philly gets most of its major bigger snowstorms from nor’easters, which tap the moisture of the Atlantic Ocean. The onshore winds can also import warm air from the ocean, and this time of year ocean temperatures still are well into the 40s. That’s why snow changes to rain so often around here early in the winter. It takes time for the ocean and the snow-making upper atmosphere to cool, and the snow season peaks in late January into February.

    That doesn’t mean a storm can’t pop before then.

    A very snowy anniversary

    It so happens that next month is the 30th anniversary of Philly’s record 30.7-inch snowfall of Jan. 7-8.

    It was so unbelievable that the record wasn’t verified officially until four years later, after NOAA commissioned a federal investigation. It turned out that the snow was not actually measured, but inferred from the liquid content of the melted snow and the air temperatures.

    The investigators — David Robinson, the Rutgers University professor who is the longtime New Jersey state climatologist and an international snow authority, and Jon Nese, who then was the Franklin Institute meteorologist — affirmed the total.

    They concluded that the snow reports in neighboring towns were close enough to support PHL’s.

    Snow is a weighty matter

    Large snowflakes fall as pedestrians make their way in Center City. Flakes come various shapes and sizes … and weights.

    In the standard language used by the National Weather Service and commercial outfits, that certainly qualified as a “heavy” snowfall.

    But it was the antithesis of “heavy,” at least in terms of relative weight. Snow comes not only in different shapes, but also in very different weights, depending on the snow-to-liquid ratios. On average around here, an inch of liquid yields about a foot of snow, a 12-1 ratio.

    However, when temperatures are close to freezing as they were last Sunday, the snow has a higher liquid content and is thus heavier. On Sunday, 5 inches may have felt more like 8 to the average shovel. That’s heavy snow.

    When it’s cold, as it was on Jan. 7, 1996 — temperatures were in the teens during the day — the flakes are way drier. The ratio for the storm was closer to 20-1, and overall the flakes were a whole lot lighter.

    “Heavy” snow “applies to visibility ratios,” said Jim Eberwine, longtime meteorologist with the National Weather Service local offices, adding it might be time to reconsider the use of that adjective.

    “Some things should be updated,” he said.

    How about: Snowfall rates can be intense at times?

    Snow: It’s a Northern Hemisphere thing

    It’s Janaury in the Miami of South America, Punta del Este, Uruguay. It doesn’t snow much there in their winter either.

    The solstice also marks the beginning of the astronomical summer in the Southern Hemisphere, so residents south of the equator probably won’t be using snowblowers for the next several months.

    In fact, they won’t be seeing a whole lot of snow there during the winter. It snows robustly in the Andes and other mountain regions, but not in major population centers, the AccuWeather people note.

    NOAA’s National Center for Environmental Information doesn’t bother to track snow cover in the Southern Hemisphere, for a couple of reasons, including that it’s 80% covered by climate-moderating water.

    Plus its major cities are located at latitudes where snow is scarce.

    How much for Philly this winter?

    The Butler family finds a (small) hill to sled on in Wallworth Park in Cherry Hill after last Sunday’s snowfall. The 4.2 inches meashred in Philly was more than half of what fell all last winter.

    By contrast, the Northern Hemisphere has a plentiful supply of metropolitan areas that experience ruler-worthy snowfalls, including Philadelphia.

    Making seasonal snow forecasts in this region isn’t quite like picking lottery numbers, but reasonably close. Seasonal totals have varied from 78.7 inches in 2009-10 to nothing in 1972-73. NOAA’s Climate Prediction Center doesn’t touch the stuff.

    The guesses for this year are in, and here is a partial list with what’s out there: The “normal” season total is 23.1 inches.

    Fox29 — 16 inches

    AccuWeather/6abc — 14 to 18 inches

    CBS3 — 18 to 24 inches

    Arcfield Weather — 22 to 26 inches

    WeatherBell Analytics — 22 inches

    One prediction they all have in common: The winter of 2025-26 will out-snow that of 2024-25.

    That won’t be hard.

  • Soaked ground and 60-mph wind gusts could cause outages and commuting woes around Philly

    Soaked ground and 60-mph wind gusts could cause outages and commuting woes around Philly

    What’s left of the season’s first snowfall is all but gone with the wind — and the heftiest rains since October. And having done its best to disrupt Friday’s morning commute, the weather evidently is executing an afternoon encore.

    After backing off for a few hours, the winds came back with a vengeance Friday afternoon. A thunderstorm gust of 62 mph was recorded at Philadelphia International Airport at 2:35 p.m.

    The weather service’s wind advisory for the entire region remains in effect until 1 a.m. Saturday, and conspiring with snow melt to saturate the soils, SEPTA is particularly concerned about the potential for uprooted trees along its Regional Rail lines, said media relations director Andrew Busch.

    “The recipe for problems is there,” he said. “We will have crews stationed across the system to respond quickly.”

    Peco heard the rumors, and while the utility is “not expecting impacts, we’re going to continue to monitor conditions,“ said Candice Womer, senior communications specialist.

    The deciduous trees are mostly bare, so winds can sail through branches that are not weighed down with leaves, but the weather service advises that “some power outages” are possible.

    About 16,500 outages were reported at midafternoon.

    An additional concern was the predicted wind shift during the day, from southerly in the morning to westerly in the afternoon, and how that might stress vulnerable trees, Womer said.

    The strongest winds will occur during the afternoon

    The gusts are likely to be “widespread” during the afternoon, said Paul Fitzsimmons, a lead meteorologist at the weather service’s Mount Holly office. That would be after the rain-producing front crosses through the region and winds become westerly, peaking in time for the afternoon commute. Gusts to 50 mph are possible.

    Rain totals in the Philly area are expected to be in the 1-to-1.5-inch range, Fitzsimmons said.

    No stream flooding is anticipated, however, as levels are quite low. Despite the snow and a decent soaking on Dec. 2, precipitation the last two months is only about 75% of normal throughout the region, according to the National Oceanic and Atmospheric Administration’s Middle Atlantic River Forecast Center.

    How dry we’ve been

    The gusts aside — not a trivial omission — this system should produce a “beneficial rain,” the weather service notes.

    A drought warning remains in effect for all of New Jersey.

    Water levels are so low that computer models show only about a 10% chance of streams reaching even the preflood “action” phase.

    In the interagency U.S. Drought Monitor map posted Thursday morning, most of Philadelphia, adjacent South Jersey, and Chester County were in the “severe drought” category, along with portions of Bucks, Delaware, and Montgomery Counties.

    Most of Pennsylvania and New Jersey were in at least “abnormally dry” conditions.

    The forecast for the weekend

    After the winds die down Friday evening, the region should be in for a dry but chilly weekend.

    Temperatures during the day Friday are forecast to dive from a high in the 50s in the morning to the 30s by nightfall, and they won’t get out of the 30s on Saturday.

    Sunday’s forecast high in the mid-40s would be close to normal for the date.

    Peeking ahead, the prospects of a white Christmas are not especially promising.

    The region may have to settle for a wet one. Rain is possible Christmas Day with highs in the 40s. That’s not quite what Irving Berlin had in mind.

  • Trump officials say they will dismantle ‘global mother ship’ of climate and weather forecasting

    Trump officials say they will dismantle ‘global mother ship’ of climate and weather forecasting

    The Trump administration said Tuesday it was breaking up one of the world’s preeminent earth and atmospheric research institutions, based in Colorado, over concerns about “climate alarmism” — a move that comes amid escalating attacks from the White House against the state’s Democratic lawmakers.

    “The National Science Foundation will be breaking up the National Center for Atmospheric Research (NCAR) in Boulder, Colorado,” wrote Russell Vought, the director of the White House Office of Management and Budget on X. “This facility is one of the largest sources of climate alarmism in the country.”

    The plan was first reported by USA Today.

    The NCAR laboratory in Boulder was founded in 1960 at the base of the Rocky Mountains to conduct research and educate future scientists. Its resources include supercomputers, valuable datasets, and high-tech research planes.

    The announcement drew outrage and concern from scientists and local lawmakers, who said it could imperil the country’s weather and climate forecasting, and appeared to take officials and employees by surprise.

    NCAR’s dismantling would be a major loss for scientific research, said Kevin Trenberth, a distinguished scholar at NCAR and an honorary academic in physics at the University of Auckland in New Zealand.

    Trenberth, who joined NCAR in 1984 and officially retired in 2020, said the research center is key to advanced climate science discoveries as well as in informing the climate models that produce the weather forecasts we see on the nightly news.

    Colorado Gov. Jared Polis said in a statement that the state had not received information about the administration’s intentions to dismantle NCAR.

    “If true, public safety is at risk and science is being attacked,” said Polis. “Climate change is real, but the work of NCAR goes far beyond climate science. NCAR delivers data around severe weather events like fires and floods that help our country save lives and property, and prevent devastation for families.”

    The action comes as Republicans have escalated their attacks on Polis and others in the state for their handling of a case involving Tina Peters, a former county clerk in Colorado who was convicted in state court on felony charges related to efforts to overturn the 2020 presidential election. President Donald Trump announced last week that he is pardoning Peters, who is serving a nine-year sentence, but it is unclear whether Trump has that authority, because she was not convicted in federal court.

    In a joint statement, Colorado’s two Democratic senators, John Hickenlooper and Michael Bennet, and Rep. Joe Neguse (D., Colo.) slammed the move and vowed to fight back against it.

    In his social media post, Vought said that “any vital activities such as weather research will be moved to another entity or location” — but did not specify further.

    “The Colorado governor obviously isn’t willing to work with the president,” said a White House official, who spoke on the condition of anonymity because they were not authorized to discuss the matter publicly.

    The official declined to cite any specifics about how Polis is refusing to cooperate, from the administration’s perspective, but denied that the move was in response to the state’s refusal to release Peters from prison.

    The facility “is not in line with the president’s agenda,” the official added, noting that it had “been on the radar” of the administration “for a while.”

    The National Science Foundation, the federal science agency that funds the center, was blindsided by the announcement, according to a person familiar with NSF operations who spoke on the condition of anonymity to avoid retribution. But they said facilities managers at NSF will need to be involved in moving assets or capabilities. An NSF spokesman did not immediately respond to questions about the plan to dismantle NCAR.

    Antonio Busalacchi, the president of the University Corporation for Atmospheric Research, which oversees NCAR, said it was aware of reports to break up the center but did not have “additional information about any such plan.”

    “Any plans to dismantle NSF NCAR would set back our nation’s ability to predict, prepare for, and respond to severe weather and other natural disasters,” Busalacchi said.

    An internal email obtained by the Washington Post, sent Tuesday night, emphasized the critical work NCAR does for “community safety and resilience.”

    Busalacchi wrote that the news had come as a shock, and the institution had reached out to NSF for more information. “We understand that this situation is incredibly distressing, and we ask that you all continue doing what you have done so well all year — provide support for one another as we navigate this turbulent time,” Busalacchi wrote.

    The center is “quite literally our global mother ship,” Katharine Hayhoe, a Texas Tech University professor and chief scientist for the Nature Conservancy, wrote on X. “Dismantling NCAR is like taking a sledgehammer to the keystone holding up our scientific understanding of the planet.”

    NCAR plays a unique role in the scientific community by bringing together otherwise siloed specialists to collaborate on some of the biggest climate and weather questions of our time, Caspar Ammann, a former research scientist at the center, said in an email.

    “Without NCAR, a lot could not happen,” he said. “A lot of research at US Universities would immediately get hampered, industry would lose access to reliable base data.”

    Ammann added that around the world, weather and climate services use NCAR modeling and forecasting tools.

    The Colorado-based center draws scientists and lecturers from all over the world, and through its education programs has helped produce future scientists, Trenberth said.

    He said he feared not just for the discoveries and data that would be lost if the center were to close, but for the early careers that could also be affected or destroyed.

    “If this sort of thing happens, things will go on for a little while,” he said. “But the next generation of people who deal with weather and science in the United States will be lost.”

  • Saturn’s moon Titan may not have a buried ocean as long suspected, new study suggests

    Saturn’s moon Titan may not have a buried ocean as long suspected, new study suggests

    CAPE CANAVERAL, Fla. — Saturn’s giant moon Titan may not have a vast underground ocean after all.

    Titan instead may hold deep layers of ice and slush more akin to Earth’s polar seas, with pockets of melted water where life could possibly survive and even thrive, scientists reported Wednesday.

    The team led by researchers at NASA’s Jet Propulsion Laboratory challenged the decade-long assumption of a buried global ocean at Titan after taking a fresh look at observations made years ago by NASA’s Cassini spacecraft around Saturn.

    They stress that no one has found any signs of life at Titan, the solar system’s second-largest moon spanning 3,200 miles and brimming with lakes of liquid methane on its frosty surface.

    But with the latest findings suggesting a slushy, near-melting environment, “there is strong justification for continued optimism regarding the potential for extraterrestrial life,” said the University of Washington’s Baptiste Journaux, who took part in the study published in the journal Nature.

    As to what form of life that might be, possibly strictly microscopic, “nature has repeatedly demonstrated far greater creativity than the most imaginative scientists,” he said in an email.

    JPL’s Flavio Petricca, the lead author, said Titan’s ocean may have frozen in the past and is currently melting, or its hydrosphere might be evolving toward complete freezing.

    Computer models suggest these layers of ice, slush, and water extend to a depth of more than 340 miles. The outer ice shell is thought to be about 100 miles deep, covering layers of slush and pools of water that could go down another 250 miles. This water could be as warm as 68 degrees Fahrenheit.

    Because Titan is tidally locked, the same side of the moon faces Saturn all the time, just like our own moon and Earth. Saturn’s gravitational pull is so intense that it deforms the moon’s surface, creating bulges as high as 30 feet when the two bodies are closest.

    Through improved data processing, Petricca and his team managed to measure the timing between the peak gravitational tug and the rising of Titan’s surface. If the moon held a wet ocean, the effect would be immediate, Petricca said, but a 15-hour gap was detected, indicating an interior of slushy ice with pockets of liquid water. Computer modeling of Titan’s orientation in space supported their theory.

    Sapienza University of Rome’s Luciano Iess, whose previous studies using Cassini data indicated a hidden ocean at Titan, is not convinced by the latest findings.

    While “certainly intriguing and will stimulate renewed discussion … at present, the available evidence looks certainly not sufficient to exclude Titan from the family of ocean worlds,” Iess said in an email.

    NASA’s planned Dragonfly mission — featuring a helicopter-type craft due to launch to Titan later this decade — is expected to provide more clarity on the moon’s innards. Journaux is part of that team.

    Saturn leads the solar system’s moon inventory with 274. Jupiter’s moon Ganymede is just a little larger than Titan, with a possible underground ocean. Other suspected water worlds include Saturn’s Enceladus and Jupiter’s Europa, both of which are believed to have geysers of water erupting from their frozen crusts.

    Launched in 1997, Cassini reached Saturn in 2004, orbiting the ringed planet and flying past its moons until deliberately plunging through Saturn’s atmosphere in 2017.

  • After more icy mornings in the Philly region, the snow may disappear in a hurry Thursday

    After more icy mornings in the Philly region, the snow may disappear in a hurry Thursday

    That icy glaze that has appeared on streets, sidewalks, and driveways this week reappeared Wednesday and will make an encore Thursday morning as water continues to ooze from the snowpack by day and freeze at night.

    So-called black ice — ice that masquerades as harmless wetness — is especially dangerous, officials warn, and conditions are ripe for a harvest, given the generous snowpacks.

    “Refreezing and black ice are definitely a concern,” said PennDOT spokesperson Brad Rudolph. “We will continue to treat areas as needed.”

    SEPTA advised commuter to watch out for ice on platforms, walkways, and in parking lots.

    Temperatures early Wednesday fell into the teens throughout the region — save for Philadelphia International Airport where the low was 26 — and on Thursday are due to drop into the 20s region-wide.

    But along with that winter landscape, the atmosphere over the region is going to undergo radical changes by the end of the workweek, forecasters say, with a rapid but short-lived warmup, and something that’s been missing around here lately — a soaking rain.

    As for more snow, the atmospheric scientists are saying it’s probably safe to put away the shovels for a while, and not just in the Philly region.

    “In my opinion, cold looks hard to come by for most of the United States through the remainder of December,” said Amy Butler, research scientist at the NOAA Chemical Sciences Laboratory.

    In short, prepare for a more typical Philadelphia December.

    “With the pattern changing, we’re kind of getting closer to where we should be this time of year,” said Mike Lee, a lead meteorologist at the National Weather Service Office in Mount Holly.

    The forecast for the rest of the week

    Wednesday should be at least partially sunny with some substantial melting as temperatures are due to crack 40 degrees by early afternoon.

    Then after one more overnight with readings dropping into the melt-freezing 20s, Thursday is forecast to become the first day with above-normal temperatures in Philadelphia since the Wednesday before Thanksgiving.

    As temperatures rise through the 40s, several hours of soaking rain are forecast to begin in the early evening with the potential for up to an inch.

    Throughout the region the snowpack contains about a half inch of water that will be heading to local storm sewers and local waterways, said the weather service’s Lee.

    In addition to the rain, the high moisture content of the air is one of nature’s most-efficient snow-removal tools. When warm, moist air comes in contact with snow, it gives off a latent heating effect that accelerates melting.

    “We’ll have to watch for the possibility of some localized flooding,” said Paul Dorian, a meteorologist with Arcfield Weather.

    For now, Lee said, the weather service isn’t contemplating flood advisories. Precipitation the last 90 days has been substantially below normal throughout the region, and a drought warning remains in effect for New Jersey.

    The outlook for the weekend and beyond

    Friday’s forecast high in the mid-50s is likely to occur in the early morning hours, and then temperatures are forecast to crash, with wind gusts to 40 mph possible.

    Saturday is expected to be dry but chilly, with readings in the low 40s, warmer than it’s been but still several degrees below normal, and in the mid-40s Sunday, closer to the long-term averages.

    The polar vortex, the persistent low pressure system that spins around the Arctic and confines the cold air to the ice box of the planet, has been strengthening, said Butler.

    It’s possible that it would undergo “stretching” and allow cold air to sink into parts of the contiguous United States, but “it’s not a signal that is very robust,” she said.

    For now, she said no obvious dominant feature is emerging that would define the winter.

    La Niña conditions continue in the tropical Pacific, where vast expanses of the sea surfaces are about a degree below normal. La Niña can have powerful effects on west-to-east winds that ferry weather to the United States.

    In this case, however, La Niña is currently weak, meaning that its influence over global seasonal patterns is also weak, said Emily Becker, scientist with the University of Miami/Cooperative Institute for Marine & Atmospheric Studies.

    For now, it would be prudent to savor what’s left of the snow cover, and it wouldn’t hurt to spread a little sand or gravel on the driveway or the front steps before going to bed.

  • The snow and ice are sticking around the Philly region after an unusual storm

    The snow and ice are sticking around the Philly region after an unusual storm

    What have become the glacial remnants of a picturesque and a meteorologically unusual snowfall that tufted the trees and bushes with a cottony whiteness are likely to stay around for a few more days.

    In what has been quite a chilly December, with not a single day of above-normal temperatures, readings tumbled into the teens for the second consecutive morning on Tuesday and not make it out of freezing in the afternoon.

    Expect more ice and stealth “black ice,” re-frozen snow melt that forms on driveways, sidewalks and other surfaces, again Wednesday morning.

    But if you’re getting tired of salting and chipping ice after those overnight freeze-ups, you’re about to get some help.

    A warm-up is forecast to get underway Wednesday, and come Thursday, which is slated to be the warmest day since before Thanksgiving, the atmosphere is expected to train its snow-removal guns on the region.

    Forecasters see a surge of snow-erasing warmth and a significant — and badly needed — rainfall Thursday night that should restore the landscape to a condition more familiar to Philadelphians and ease precipitation deficits.

    As for the prospects of a winter-wonderland encore, nothing is on the horizon in the near term, said Nick Guzzo, meteorologist with the National Weather Service in Mount Holly.

    Said Matt Benz, senior meteorologist with AccuWeather Inc, “For folks looking for more snow, this might have been it.”

    At least for now and perhaps until after Christmas, or later. But, “Winter’s not done yet,” Benz said.

    Willow, a West Highland, is with Amanda and David York on a walk in Maria Barnaby Greenwald Memorial Park in Cherry Hill on Sunday morning.

    The warmup in Philly is expected to be brief

    Temperatures could go as high as 55 degrees Thursday, Benz said. Then after a cold front passes through, temperatures will fall during the day Friday.

    This won’t be an Arctic front like the one that gave Philly its coldest day of the season on Monday, with a high of 28. However, the forecasts call for readings to be no higher than the 30s on Saturday, and mid-40s on Sunday, which is close to the longer-term normal high, followed by several degrees chillier on Monday.

    What’s expected for the next two weeks

    In its updated extended outlooks on Monday, NOAA’s Climate Prediction Center had just about the entire country with above-normal temperatures through Dec. 29, with a notable exception — the Northeast, including Philadelphia.

    Predicted upper-air conditions in the Arctic and the North Atlantic would argue against above-normal temperatures around here during the period, climate center forecaster Thomas Collow said.

    The center wisely eschews the snow-forecasting business.

    Philly just had quite the unusual snow event

    Regardless of what happens the rest of the way, the winter of 2025-26 will be snowier than at least seven others in the period of snow records that date to the winter of 1884-85.

    The 4.2 inches measured officially at Philadelphia International Airport Sunday is a half-inch above the long-term average for the season to date.

    How much snow fell near you, mapped

    Granted almost any substantial snowfall would seem exceptional these days around here, but this one truly was, said the weather service’s Zach Cooper, a meteorologist in the Mount Holly office.

    Most of Philly’s significant snows are the result of coastal storms that mine moist air from the ocean.

    That wasn’t the case Sunday.

    ”In some ways it was a bit of a unique situation for us, especially to get the amounts that we did,” he said.

    The snow was generated by a weak “clipper system,” a storm that dives out of southwestern Canada and usually has minor impacts around here, and a disturbance in the upper atmosphere.

    Totals generally ranged from 4 to 8 inches across the region. Totals were less around the city in part because temperatures took their good, old time dropping below freezing.

    Marginal temperatures also were a factor in the spread of accumulations. They added some extra weight and heft to the flakes that glommed on the branches and what remains of the foliage with tenacity.

    While the show will have a limited run, the region learned anew that snow and ice may be a pain, but nothing decorates like nature.

  • How much snow fell near you, mapped

    How much snow fell near you, mapped

    The Philadelphia region’s first snowfall of the season ended up having quite a March-like quality.

    Totals generally ranged from 4 to 8 inches, but the snow literally was so heavy that the average shoveler may have had a hard time discerning the difference.

    “When I was shoveling my car out, it felt rough,” said Michael Silva, meteorologist at the National Weather Service Office in Mount Holly. Silva lives in Mount Laurel, where an unofficial 7 inches was reported.

    The snow was so weighty because it had a high liquid content, the result of temperatures close to the freezing mark, as so often happens in March. The borderline temperatures also would help explain the range in accumulations, he said.

    The snow glommed onto the trees, weighing down branches. In fact it took down a branch outside the Mount Holly office that damaged a federal car (sorry, taxpayers).

    The highest amounts, just over 8 inches, were recorded in Chester and Bucks Counties.

    Officially, at Philadelphia International Airport, where temperatures didn’t get below freezing until midmorning Sunday, 4.2 inches was measured.

    By contrast, Boston has measured only 3.1 inches so far.

    Here are the snowfall totals posted by the weather service as of 10 a.m. Monday.

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  • Snow is a near certainty in Philly this weekend, and it won’t melt quickly

    Snow is a near certainty in Philly this weekend, and it won’t melt quickly

    The first measurable snowfall of the winter of 2025-26 evidently is all but a done deal for Philly this weekend, and it has a chance to be the biggest in two winters — not that the bar is ultra-high in a period when snow has been mightily lacking.

    The National Weather Service has issued a winter storm warning for 3 to 5 inches of snow across the region, with a near 100% likelihood of at least an inch of snow.

    That was in line with the AccuWeather Inc. outlook.

    The weather service has a 76% chance of at least 4 inches and 43% of 6 or more.

    With the caveat that timing and duration of precipitation aren’t in the wheelhouse of atmospheric science, the weather service is expecting snow or snow mixed with rain to start late Saturday night.

    If it’s a mix at the outset it would quickly become all snow as temperatures fall below freezing, and continue into midmorning.

    The snow would be generated primarily by an upper-air disturbance, said Matt Benz, senior meteorologist for AccuWeather. It’s possible that the storm may regroup off the coast, however, that “probably will form too late to have any impact.”

    In a forecast discussion, the weather service said inch-an-hour snowfall rates are possible early Sunday.

    “There is a potential for a concentrated area of 4-5 inches of snowfall somewhere near the I-95 corridor and immediately south and east,” the forecasters said.

    They noted a 20% to 30% chance that some places get over 5 inches.

    And the snow is likely to stick around until at least midweek, with high temperatures Sunday, Monday, and Tuesday expected to be around freezing or lower and the sun angles about as low as they get.

    After that February storm, the temperature climbed to near 50 a day later, and the strengthening sun made quick work of the snow cover.

    That February snow turned out to be the biggest of a season in which the 8.1-inch total at Philadelphia International Airport barely bested the 8 inches of New Orleans. That winter, the I-95 corridor found itself in a snow hole, and Philly a snow hole within a snow hole. The highest total in the winter of 2023-24 was 4.6 inches during a snowy January week.

    Snow fell to the north, west, and south, and that trend has continued in the early going. With 6 inches so far this winter, Richmond, Va., now has measured 22.8 inches since last December, nearly triple the Philly total.

    Official totals at Philadelphia International Airport have been less than half of normal for four consecutive winters. The normal for a season is 23.2 inches.

    The meteorological winter, which began Dec. 1, certainly is off to a wintry start, with temperatures averaging more than 6 degrees below normal.

    It is not off to a particularly wet start, however, and whatever falls this weekend isn’t expected to exceed a half inch of liquid.

    In its long-term outlooks through Dec. 26, NOAA’s Climate Prediction Center is on the fence regarding whether precipitation will be above or below normal.

    With high confidence it is calling for a national warm-up.

    In any given year, the odds are greatly against Christmas snow in Philly or elsewhere along the I-95 corridor.

    But it does look like the region is about get a white Sunday.

  • Snow, up to 5 inches, is a near certainty in Philly this weekend, and it won’t melt quickly

    Snow, up to 5 inches, is a near certainty in Philly this weekend, and it won’t melt quickly

    The first measurable snowfall of the winter of 2025-26 evidently is all but a done deal for Philly this weekend, and it has a chance to be the biggest in five winters — not that the bar is ultra-high in a period when snow has been mightily lacking.

    The National Weather Service Saturday has issued a winter storm warning for 3 to 5 inches throughout the region, listing a 98% likelihood of at least an inch.

    The AccuWeather Inc. forecast was similar.

    The weather service foresaw a 76% chance of 4 inches in the immediate Philly area, and a 43% chance of 6 or more.

    With the caveat that timing and duration of precipitation aren’t in the wheelhouse of atmospheric science, the weather service is expecting snow or snow mixed with rain to start late Saturday night.

    If it’s a mix at the outset it would quickly become all snow as temperatures fall below freezing, and end around daybreak. As the weather service pointed out, the timing couldn’t be much better for minimizing disruption.

    However, snow showers and wind chills in the teens are expected when the Eagles host the Oakland Raiders in South Philly.

    The accumulating snow would be generated primarily by an upper-air disturbance, said Matt Benz, senior meteorologist with AccuWeather. It’s possible that the storm may regroup off the coast; however, that “probably will form too late to have any impact,” Benz said.

    The weather service said inch-an-hour snowfall rates are possible in the early morning hours of Sunday.

    And the snow is likely to stick around until at least midweek, with high temperatures Sunday, Monday, and Tuesday expected to be around freezing or lower and the sun angles about as low as they get.

    After a 3.1-inch snowfall in February, the temperature climbed to near 50 a day later, and the strengthening sun made quick work of the snow cover.

    That February snow turned out to be the biggest of a season in which the 8.1-inch total at Philadelphia International Airport barely bested the 8 inches of New Orleans. That winter, the I-95 corridor found itself in a snow hole, and Philly a snow hole within a snow hole. The highest total in the winter of 2023-24 was 4.6 inches during a snowy January week.

    Last season, snow fell to the north, west, and south, and that trend has continued in the early going. With 6 inches so far this winter, Richmond, Va., now has measured 22.8 inches since last December, nearly triple the Philly total.

    Official totals at Philadelphia International Airport have been significantly below normal for four consecutive winters. The normal for a season is 23.1 inches.

    The meteorological winter, which began Dec. 1, certainly is off to a wintry start, with temperatures averaging more than 6 degrees below normal.

    It is not off to a particularly wet start, however, and whatever falls this weekend isn’t expected to exceed a half inch of liquid.

    In its long-term outlooks through Dec. 26, NOAA’s Climate Prediction Center is on the fence regarding whether precipitation will be above or below normal.

    With high confidence it is calling for a national warm-up.

    In any given year, the odds are greatly against Christmas snow in Philly or elsewhere along the I-95 corridor.

    But it does look like the region is about to get a white Sunday.

  • 2 to 4 inches of snow expected this weekend in the Philly region

    2 to 4 inches of snow expected this weekend in the Philly region

    The odds are almost always stacked against a white Christmas around here, but it is looks like the region will experience a white Dec. 14.

    The National Weather Service on Friday said Philadelphia was all but certain to get at least an inch of snow during the weekend, with a general 2 to 4 inches expected, said Joe DeSilva, a meteorologist in the Mount Holly office.

    The weather service issued a winter-weather advisory for the entire region from 7 p.m. Saturday through 1 p.m. Sunday.

    A storm forming along an Arctic front combined with a strung idsturbance in the upper atmosphere were forecast to begin shaking out snowflakes very late Saturday night or early Sunday. It’s possible that the snow may be mixed with rain, at least at the outset, especially south and east of the city.

    And while this may be shocking, computer models continue to tweak outcomes, leaving “still a little bit of uncertainty how this low is going to track,” said DeSilva’s colleague Eric Hoeflich.

    However, recent model runs overall have been a shade more bullish on snow amounts than they had been, and the U.S. model has bumped up amounts slightly, said DeSilva.

    Timing and duration issues remained to be resolved, and snow could cause commuting issues in the morning. In addition to church-goers, tail-gaters will be commuting commuting to the Eagles game at Lincoln Financial Field in South Philly, and supermarkets typically experience brisk traffic in the run-up to Eagles’s games.

    The snow, however, is forecast to end well before kickoff at the Linc, scheduled for 1:15 p.m., DeSilva said.

    Some flakes were evident Thursday in the region, with Philadelphia International Airport, where winds gusted past 30 mph, reporting its third “trace” of the season.

    The renegade flakes were flying from lake-effect snows, said Bill Deger, senior meteorologist with AccuWeather Inc.

    The winds have shut off, and both Friday and Saturday were expected to be tranquil with daytime temperatures mostly in the 30s.

    And this time, that holiday least-favorite, the “wintry mix,” wouldn’t be in the mix.

    How much snow for Philly?

    AccuWeather Inc. was calling for up to 3 inches.

    If the storm is a quick mover, expect the inch, but if slows down and ripens a bit, it could be as much as 3, said AccuWeather senior meteorologist Bill Deger.

    The weather service was pretty much on board with that estimate.

    It painted 3 nches for Philly on its Friday morning snow map.

    One near-certainty: This will change.

    What time would the snow start?

    It is likely to begin very late Saturday night or very early Sunday and continue until mid- or late morning, forecasters say.

    Temperatures throughout the day are not expected to get past 30, with wind chills in the teens.

    It might feel even colder if the Eagles lose to the lowly Las Vegas Raiders.

    Regardless, everyone should be able to make it home.

    “We’re not talking a major snowstorm,” Hoeflich said.

    But this would be something a little bit different compared with recent local snow history.

    Hoeflich noted that, as happened last winter, generous snow has fallen to the north, south, and west, leaving “a giant snow hole” over the Philadelphia area.

    “It looks like that’s going to change.”