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NYC Weather Update – Dec 28, 2015

December 28, 2015Freezing Rain, NYC, Outside of NYC, Rain, Snow, Storms, Tornadoes, Weather Updateblizzard, cold front, freezing rain, ice, new york city weather, new york city wx, nyc wx, rain, sleet, snow, tornadoes, warm front, weather, winter weatherLei Zhao

After an absurdly warm start to the winter, we are about to get a dose of proper weather for this time of year. While temperatures this week and the first half of January will still above normal in many cases, they will be considerably cooler than December and be closer to normal than not. This week, we start with a messy and complex storm (the same that spawned deadly tornadoes in Texas and has brought blizzard conditions to New Mexico, and an ice storm to Oklahoma) that affects the area tonight into Tuesday with a mix of rain, sleet, freezing rain, and snow, depending on how far north you are. Yet another round rain and snow further north from the city is possible Wednesday.

Rest of today – seasonably cool with high temperatures only in the low-mid 40s. Increasing clouds ahead of a warm front that will be the focus for the precipitation later tonight. Things get interesting overnight as precipitation begins to spread over the area from southwest to northeast. Near the coast, surface temperatures are expected to remain warm enough (upper-30s) to largely preclude the possibility of significant wintry precipitation, however, sleet could mix in with rain to at the start of this storm before things shift over to all rain. Further west and north will be another story, with areas expecting anything between .25″ of ice to 2-4″ of snow/sleet accumulation before rain starts falling.

Tuesday – as temperatures warm with daybreak, wintry precipitation should transition entirely to rain. Rain is expected to last throughout most of the morning into the early afternoon hours. East winds ahead of the warm front mentioned above will be in the 15-20mph range before shifting to the north. High temperatures in the city are expected to hit the upper-40s to around 50ºF.

Wednesday – we’ll get another shot at rain as the cold front railing the warm front pictured above pushes through late on Wednesday into the overnight hours. Despite increasing clouds, forecasts still call for high temperatures in the low-50s.

Thursday – a lingering chance of rain remains on the backside of the cold front. High temperatures are expected to be about the same as Wednesday near 50.

NYC Weather Update – Mar 22, 2015

March 22, 2015Climate, NYC, Rain, Weather Updateclimate prediction center, cold front, new york city weather, nyc weather, nyc wx, spring, spring weather, warm front, warm sector, weather, winter, winter weatherLei Zhao

This upcoming week will feature some big swings in temperature, with high temperatures increasing steadily up through Thursday, when highs could 60 before a cold front swings through. Following the passage of this cold front, we dip back into the mid-40s and continue cooling into the lower-40s this weekend. The temperature trend in the medium term remains below normal, potentially well below normal even through the first week of April, as a series of cold fronts continue to allow cold Canadian air to enter the area.

Monday – an area of high pressure will yield a sparkling sunny day, but will also permit cold, Arctic air back into the region. Northwest winds combined with noticeably cold overnight lows will produce uncomfortably cold conditions. High temperatures Monday may barely break freezing. It’ll be one of the coldest day we’ve had this month.

Tuesday – also gets off to a chilly start, but high temperatures are expected to push up to around 40 (which is more than 10ºF colder than normal).

Wednesday – a clear start, but clouds will be building ahead of a warm front that will pass over the region late Wednesday. Temperatures will steadily climb to near 50, especially after the warm front passes. There will be a slight chance for rain later Wednesday in conjunction with this frontal passage.

Thursday – highs will near if not break 60, however, it is anticipated to be a overcast day with periods of rain possible throughout the day. After the warm front passes Wednesday, we’ll be firmly within the warm sector, between the warm front to our east and the approaching cold front from the west. This setup favors the influx of warm, moist air from the Gulf riding in on persistent southwesterly winds, before a dramatic shift following the cold front passing, with winds becoming west-northwest and a drop in temperatures.

Friday – high temperatures drop back in to the mid-40s, as clouds break apart and colder, dry air takes hold behind the cold front.

Below Normal Start to April

It’s close to a sure bet (70% probability) that we’ll end the month of March and start April with below normal temperatures, taking a look at the Climate Prediction Centers forecasts below. I know we’re all sick of this seemingly endless winter, but we’re still not out of the woods in terms of temperatures.

6-10 temperature outlook from the Climate Prediction Center

8-14 temperature outlook from the Climate Prediction Center

NYC Weather Update – Mar 18, 2015

March 18, 2015Climate, NYC, Snow, Weather Update, Weekendmarch, march snow, new york city weather, nyc weather, nyc wx, snow, spring, weather, winter, winter weatherLei Zhao

Just when we thought winter was on its last legs, and spring was on its way. Unfortunately, as the Climate Prediction Center forecast a couple weeks ago, a cool down is in the cards to end the month of March. In fact, it will get so cold that snow could accumulate Friday into Friday night. After a brief warmup, another shot of colder than normal air will return to grip the area to end off the month.

Thursday – a below normal, but dry day with plenty of sun and high near 40.

Friday – (ironically, first day of astronomical spring) a coastal low moving offshore of the Carolinas will then track north. Enough cold air will be in place Friday, along with a persistent northerly flow with counterclockwise circulation around the low pressure center that snow is looking likely during the course of the day. Current forecast snow accumulations are on the light side, no more than 3-4″. If temperatures are even a few degrees warmer than currently forecast, we could get away with little accumulation.

Saturday – things clear up quickly on Saturday with high temperatures back near normal in the mid-upper 40s.

Sunday – a dry cold front moves through Sunday, leading to a drop in temperatures to below normal in the upper 30s.

Cool Off Coming Up

The climate prediction center continues to point to cooler than normal temperatures for the last two weeks of March. One can only hope that the temperatures are not so cold as to allow for more snow, but I wouldn’t rule this possibility entirely out given some of the longer term forecast models.

NYC Weather Update – Mar 2, 2015

March 2, 2015Freezing Rain, NYC, Rain, Snow, Storms, Weather Updatecold front, nyc weather, nyc winter weather, rain, sleet, snow, storms, warm front, winter, winter weather, winter weather nyc, winter wxLei Zhao

March will start off with quite an active, messy week for us. During the middle of the week, we’ll see snow, rain, and then more snow, before we end off the week with temperatures well below normal once again.

Tuesday – clouds will begin to increase throughout the day with chances for snowfall increasingly steadily as well. Not much in the way of accumulating snow is expected during the day Tuesday. High temperatures around 30.

Wednesday – overnight Tuesday into Wednesday, temperatures will actually rise as a warm front pushes through. This will allow temperatures on Wednesday to top 40. Snow early on will give way to sleet, then eventually transition to all rain. This period of rain should melt some of the existing snowpack, and there could be some minor/nuisance flooding of poor drainage areas as this occurs.

Thursday – once the cold front depicted above pushes through late Wednesday, cold air will rapidly fill in behind it and allow for temperatures to drop back into the mid-20s. As this occurs, a second wave of low pressure is expected to form over the Mid-Atlantic and move over the area. This may lead to enough precipitation to warrant a Winter Storm Warning, with 6″ of snow possible by Thursday afternoon. Highs will be near 30.

Friday – as these storms finally move away, Friday will be a sunny day, but with Arctic air back in place over the area, we’ll be once again welcoming high temperatures in the mid-20s, which at this point is over 15 degrees below normal.

NYC Weather Update – Feb 24, 2015

February 24, 2015Climate, NYC, Rain, Snow, Storms, Weather Update, Weekendarctic, arctic air, arctic cold, cold, cold front, new york city weather, nyc weather, nyc wx, snow, winter, winter weather, winter weather nycLei Zhao

After that brief “warmup” during the weekend, we’re once again mired in Arctic cold air. This cold trend continues with a reinforcing shot of cold air as a cold front sweeps through Wednesday. Behind that, high pressure builds in over the area for the end of the week and into the weekend, ensuring another prolonged stretch of chilly, much below normal temperatures.

Wednesday – ahead of what will a dry cold front passing through, high temperatures may be able to climb to just about the freezing mark under mostly sunny skies.

Thursday – once the cold front moves offshore, an area of low pressure will strengthen, but remain well offshore of the area. However, precipitation may still make its way over the region, especially the far eastern areas. There’ll be a chance for snow flurries further west in the city. Temperatures will be back in the mid-20s again in the wake of that cold front.

Friday – clearing skies will be accompanied by stagnant cold temperatures with highs again in the mid-20s.

Saturday – as you’ll se below, a strong 1040mb area of high pressure will be parked over the Ohio Valley will be responsible for the sunny, but cold temperatures through at least Saturday night. Highs Saturday may approach 30ºF. Normal highs for this time of the year are closer to 40ºF.Looking Ahead

814temp.new — Climate Prediction Center’s 8-14 day temperature outlook for March 4th to March 10th, with our region in an area expected to experience below normal temperatures.

The beginning of next week looks to feature a fairly active pattern, with two storm systems passing through, one on Monday, and another on Wednesday. With the current track of the second storm, it looks like we are going to be on the south side of the low pressure center. This would allow for warmer air to wrap into the area. We could top 40ºF again, but the tradeoff will be a slushy, wet day maybe with some mixed precipitation to start. Once this second storm passes through, we return to cold temperatures once again.

NYC Weather Update – Feb 16, 2015

February 16, 2015Climate, Freezing Rain, NYC, Snow, Weather Updatearctic air, arctic airmass, cold, cold front, extreme cold, freezing rain, high pressure, low pressure, snow, weather, winter weatherLei Zhao

Sunday night’s lows were the coldest of the year thus far, indicative of the coldest airmass to hit the area in recent memory. Again, according to climatology, the last time New York City itself hit a low of zero was in January 1994. Unfortunately, the cold snap does not show any signs of abating during the week, although the first half of the week will see daytime high temperatures in the mid-upper 20s as opposed to the teens. We’ll finish the week off back into the teens before a warmup to above freezing with an approaching storm system this weekend. Behind that – you guessed it, another round of arctic air and abnormally cold temperatures.

Rest of today – cold and overcast, with high temperatures not even getting to 20 in the city. Snow should begin falling overnight, with generally light accumulations by daybreak.

Tuesday – slightly warmer with high temperatures in the mid 20s, but also with a chance for snow as a storm system now dumping snow across a vast swath of the South passes well to the south of us. We could still end up picking up 2-5″ of snow in the city, with higher amounts along the south facing shores of Long Island and minimal accumulation north of I-84.

Wednesday – a weak cold front will pass through Wednesday, and may give us a small chance for light snow, otherwise, expecting cloudy skies with high temperatures in the mid-upper 20s.

Thursday – behind that cold front, we get our next shot of Arctic air, with overnight lows into Thursday struggling to hit 10 in the city, and zero and below in outlying inland areas. Daytime highs will only be in the mid-teens despite ample sun. Thursday night, we might get another shot at low temperatures hitting zero in the city, with lows below zero across most inland locations.

Friday – basically a repeat of Thursday, sunny but with brutally cold temperatures in the mid-teens.

Over the weekend – watching for the development of a storm system that could bring some wintry mix/freezing rain to the area, but finally give us a break from below freezing temperatures.

More Cold on Tap to End February

After the weekend storm, we get yet another reinforcing blast of Arctic air to end the month of February. Below, you’ll see the Climate Prediction Center‘s 8-14 day outlook spanning February 23 – March 1. We’re in a region with a greater than 60% probability of experiencing below average temperatures for this period.

Climate Prediction Center 8-14 day outlook for Feb 23 - Mar 1 — Climate Prediction Center 8-14 day outlook for Feb 23 – Mar 1

NYC Weekend Weather – Feb 12, 2015

February 12, 2015NYC, Snow, Weather Update, Weekendarctic, cold, cold front, new york city weather, nyc weather, nyc wx, snow, snow showers, weather, wind chill, winter weatherLei Zhao

The main headline for the upcoming weekend and into next week will be the very cold airmass that will be spreading over the region, bringing with it what will likely be the coldest temperatures we’ve seen thus far this year. The coldest period over this stretch will be overnight Sunday into Monday, when low temperatures in the city could touch zero. If that does happen, it would be the first time the city has hit zero or below since January of 1994, according to National Weather Service records!

Friday – there will be a noticeable difference in daytime temperatures versus today. High temperatures are going to struggle to even hit the upper teens in the city, once the cold front responsible for the off and on flurries today passes through tonight. Overnight lows will again be in the low teens in the city, and colder in outlying suburbs.

Saturday – another clipper-type system will move quickly through the area on Saturday, setting off a period of snow showers that could end up dropping 1-2″ across the region. High temperatures will warm up slightly – if you can call a high near 30 a warm up! Overnight, winds will begin to pick up, with wind chills between -5ºF to -15ºF.

Sunday – a stiff northwest wind will pick up. The clipper system that passes Saturday will rapidly intensify as it moves over the Atlantic. This will set up an increasingly tight pressure gradient with a high pressure center over the Great Lakes. This setup will swing the door wide open for Arctic air to blast into the region. High temperatures Sunday will be in the mid-teens in the city, and overnight lows may be as cold as zero or just below zero. Regardless, the sustained northwest winds will yield wind chill values between -15ºF to -25ºF.

Monday, President’s Day – sunny skies, but that Arctic airmass will still be very much in control, with temperatures struggling to hit 20.

Tuesday – a return to temperatures near freezing again with an approaching low pressure system that will deliver our next chance at precipitation late Tuesday into Wednesday.

NYC Weather Update – Feb 8, 2015

February 8, 2015Freezing Rain, NYC, Snow, Weather Updatearctic, arctic cold, cold, freezing rain, ice, icing, nyc weather, nyc wx, snow, snowfall, weather, winter, winter weather, wintry mix, wxLei Zhao

Another messy start to the work week is in store for us tonight and into Monday night as we endure a long duration, though relatively light intensity winter storm. Luckily for us, the storm track means we’ll avoid the worst impacts of heavy snow (New England will get the worst of it again). There’s some concern for icing again, although the impact should be slightly less serious than last Monday. The rest of the week will be precipitation free, with the exception of some snow showers possible Thursday. Following these snow showers, another shot of brutally cold Arctic air is expected by week’s end, such that highs will only be in the low 20s and even upper teens.

Monday – as you can see from below, the snowfall totals for the southern portion of the NYC area are on the very low end, only 1-2″ expected in NYC and in Long Island. The higher snowfall totals will be north of I-84 and into Connecticut, with the far northern suburbs getting a chance at over 6″. Bear in mind, the snow is expected over an extended period starting tonight through Monday night.

Ice is a bigger concern for the immediate coastal areas that will see less snow. High temperatures during the day Monday be below freezing, so freezing rain is expected and could deposit between 0.15″-0.25″ of ice when all is said and done. The majority of this is expected to fall Monday morning before temperatures cool off at the coast and precipitation switches back to all snow.

Tuesday – high temperatures should be right around freezing with clouds diminishing through the day as the storm system from Monday pulls to the east.

Wednesday – a sunny day expected with highs again near freezing.

Thursday – we get our next chance at snow, on the light side, with a passing low pressure system forming over the Great Lakes and moving east towards us high temperatures will be again around freezing.

Friday – a sunny, but frigid day with highs expected to only be in the upper teens and low 20s. As you can see from the chart above, to the west of the low affecting our area on Thursday, there is an area of high pressure which will usher in that reinforcing blast of Arctic air.

NYC Weather Update – Feb 3, 2015

February 3, 2015NYC, Snow, Storms, Weather Updatearctic front, cold, cold front, nyc weather, nyc wx, stationary front, weather, winter, winter weather, wxLei Zhao

The low overall snowfall totals for NYC yesterday wasn’t so much a problem as the significant icing that resulted from an extended period of freezing rain. Ironically, a week the city government took criticism for shutting down the transit system for blockbuster blizzard that did not come to pass here, it was 1/4″ coating of ice that wreaked havoc on the entire transit system (the hours long complete suspension of the 7 train was an extreme example of this). We do get a couple more shots at snow, once tomorrow night into Thursday, and then again during the weekend, but at this time neither event looks to be nearly as high impact as what we’ve experienced the last two weeks.

Wednesday – will be comparatively mild in the context of the rest of the week and the weather we’ve had recently. High temperatures may actually even hit 40 (slightly above normal). However, as a cold front approaches from the west, we’ll have an increasing chance for snow showers, which maybe mixed with rain at the coast during the earlier part of the evening.

Thursday – chance for snow showers continues along the vicinity of the frontal boundary as it passes over us. Following the passage of that cold front, temperatures take a serious drop as northwest winds allow for Arctic air to make a comeback into the area. Lows overnight Thursday could be as low as the single digits for the city and below zero for outlying suburbs. Coupled with a northwest wind of 15-20mph, this would produce dangerously cold wind chill values.

Generally low snowfall totals expected across the region from this event

Friday – high pressure builds in briefly for Friday, giving us the only guaranteed dry day through the forecast period. It will still be cold with highs only in the low 20s.

Saturday – an arctic front will be approaching during the day Saturday, and ahead of the front, we’ll actually about normal temperatures in the upper 30s due to southwest flow. Clouds build in and the chance for snow showers builds during the later part of the day into the overnight.

Sunday – the arctic front mentioned above moves over us but then it looks like it will stall in our vicinity for an extended period from Sunday into Monday. High temperatures will cool to around freezing in the wake of that frontal passage.

At this time, it’s too early to know exactly how much snow we would pick up. It does appear that the precipitation with this system will be generally on the lighter side, except as the low pressure center depicted over southern Illinois in the graphic below approaches the coast. Once it arrives just west of the coast, it could draw in some moisture off the ocean as the counterclockwise cyclonic flow around the eastern periphery of the low induces an extended period of onshore flow (like a sea breeze, except in this case, the air over the water is actually warmer than it is over the snowpack on the land). If this onshore flow is robust enough, it could warm coastal areas up enough to get some rain out of the storm.

You can see the distinct separation between warm and cold airmasses demarcated by the stationary front depicted in the image above - the front separates the areas with the blue dotted lines from the areas of the warm dotted lines. — You can see the distinct separation between warm and cold airmasses demarcated by the stationary front depicted in the image above – the front separates the areas with the blue dotted lines from the areas of the warm dotted lines.

NYC Blizzard Update – Jan 26, 2015

January 26, 2015Noreaster, NYC, Snow, Storms, Weather Update2015 northeast blizzard, blizzard, heavy snow, new york city blizzard, noreaster, nyc blizzard, nyc weather, nyc wx, snow, thundersnow, wind, wind gusts, winter storm, winter weather, wxLei Zhao

A major nor’easter will be bringing a high impact blizzard throughout the NYC region tonight through Tuesday midday. Beginning this evening, snowfall will increase in coverage from south to north. Periods of heavy snow are expected with snowfall rates of 2-4″ per hour, with thundersnow occurring in the heaviest bands of snow. Extended periods of high winds, with sustained winds at least 35mph and gusts over 40mph (even up to 60mph) will lead to blowing and drifting snow, blizzard conditions, and near-zero visibility. Widespread snowfall totals of between 18″-24″ possible throughout the area, with locally higher amounts.

Snowfall Totals

Since yesterday afternoon, forecast models have backed off a bit on the overall total accumulations. At this point yesterday, the quantitative precipitation forecast (liquid water equivalent total) was as high as 2.7-2.8″ and broadly over 2.5″ across much of the area. As seen below, those liquid water equivalent numbers have gone down by about half an inch.

This decrease in overall precipitable water has led to a corresponding downgrading of the overall snowfall totals. Using a 12:1 snow to water ratio, a drop in precipitable water by half an inch translates to a decrease in snow totals by 6″. Indeed, the National Weather Service has decreased the likely totals from 27″+ for many places to closer to 20-22″.

Highest probabilities for snowfall totals in excess of 18" during the 48 hour period ending 7AM Wednesday now rests over Southern New England, with the bullseye setting up right over Boston and immediate suburbs. — Highest probabilities for snowfall totals in excess of 18″ during the 48 hour period ending 7AM Wednesday now rests over Southern New England, with the bullseye setting up right over Boston and immediate suburbs. Here in NYC, we are in the range of 30%-50% probability of receiving over 18″ – notice how abruptly the probability goes up as you go further north and east.

Timing

Light snow has already begun falling over the area, however the heaviest snow will not be occurring until after 8PM tonight. The most intense period of this storm is expected overnight tonight, as a deformation banding feature forms and begins moving slowly inland. Based on the simulated radar loop below from the NAM (North American Model), the peak intensity of snowfall looks like it will occur between 1AM-7AM overnight into Tuesday. Snow appears to taper off over NYC by 1PM tomorrow.

It does appear that a secondary set of banding snow will linger over eastern areas of the metro region throughout the afternoon Tuesday until as late as 4PM tomorrow.

By the way, part of the reason the main area of highest snowfall totals is now shifting to Southern New England and Boston is because it is anticipated that these areas will see moderate to heavy snow for much longer than we will here.

NAM model simulated radar output for this storm

Impacts

Snow, heavy at times, beginning in earnest this evening especially after 8PM. Some thundersnow possible, with the most intense snow occurring overnight. Strong sustained winds up to 35mph with gusts over 40mph and as high as 60mph will lead to blizzard conditions with blowing and drifting snow cutting visibilities down to near zero.

Caveats

Forecasters have been pointing out that there continues to be some slight disagreements between different models even though this storm is imminent. Snowfall total forecasts for storms like this one are notoriously difficult to predict with a high degree of accuracy prior to the event itself. This is due to the fact that the exact placement, movement, and intensity of the deformation banding feature on the northwest flank of the low pressure center is hard to foresee until the storm is ongoing. With snowfall rates as high as 2-4″ per hour within this banding feature, a difference of a couple hours under it could translate to 4-8″ difference in overall accumulation in any one location. Same thing with location, as one location that misses the most intense portion of the banding feature could easily miss out on 6″+ in total accumulation. Furthermore, a slight change in the thermal profiles within this type of storm could alter the snow to water ratio to be higher, and of course, a change from 12:1 to 15:1 would result in a dramatic difference in totals.

LZ | Weather

Weather updates & posts for NYC region