Category Archives: NYC

NY Weather Update – Mar 19, 2018

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It sounds like a broken record at this point, but another week, yet another nor’easter with a chance of snow, arriving on the second day of spring no less! As with previous storms, how much snow we get will hinge critically on the storm’s track and proximity to shore. Looking ahead past the storm, temperatures remain subdued and below normal for this time of year.

Rest of today – sunny, high temperatures in the low-40s.

Tuesday – increasing clouds, with a chance for rain snow mix later in the day. High temperatures in the upper-30s.

Wednesday – snow developing overnight and continuing through the day. Accumulating snow currently forecast to be light in the 1-3″ range. This could increase though, based on current forecast ensemble totals ranging 5-6″. The caveat is that blacktop will probably be largely snow free due to the high sun angle.

Thursday – conditions improving overnight and mostly sunny skies with highs in the mid-40s. Snow should melt quickly with the high sun angle and temperatures.

NYC Weekend Weather – Mar 16, 2018

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An uneventful, though kind of cold weekend is in store for the NYC area. Great news for those of you going out for St. Patrick’s Day festivities. Looking ahead into mid-week next week, we have the potential for yet another nor’easter impacting the region with, you guessed it, the possibility for more snow.

Rest of today – partly sunny to mostly cloudy skies with a high near 40°F.

Saturday (St. Patrick’s Day) – warmer, sunny, with a high in the mid-40s, pretty much ideal conditions for the parade.

Sunday – sunny, high in the low-40s. High pressure will be in control of the area.

Monday – mostly sunny with highs in the mid-40s.

Why Seemingly Unending Conveyor Belt of Nor’easters?

The simple answer: The Greenland Block. You may have heard the term “blocking high” mentioned in regards to the anomalously active and cold weather pattern over the Northeast this month. In essence, what’s happened is that a strong ridge of persistent high pressure has formed over Greenland this month. Very cold air over snow-covered landmasses like Greenland is often quite stable. Colder, denser air, also increases surface pressures.

Cyclonic flow around such an area of strong high pressure can wreak havoc with the polar jet stream – diverting its normal flow around the high. This can (and has in our case) lead to the polar jet diving far to the south, allowing large intrusions of Arctic air into the Eastern US. Jet streams can also enhance storms via upper level divergence, lowering surface pressures. Lastly, the blocking high can slow the normal eastward progression of storm systems, causing storms to linger over areas and extended periods of precipitation and coastal impacts in the case of nor’easters.

The Greenland Block is correlated with an index called the North Atlantic Oscillation. When values of this index are negative, it’s more likely that such a blocking pattern arises. Lucky for us, it appears that we may finally get a break in this pattern towards the end of the month.

 

 

NYC Weather Update – Mar 12, 2018

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Another week, another nor’easter! Luckily, this time around, the storm will stay outside of the notorious 40ºN 70ºW benchmark, meaning that impacts for NYC should be relatively light. On the backside of this storm, weather should be fairly innocuous and average for this time of the year.

Rest of today – increasing clouds ahead of this incoming storm. High temperatures in the mid-40s. Temperatures drop to near freezing overnight in the city, setting the stage for snow overnight as the storm approaches and rapidly strengthens.

Tuesday – lingering snow from overnight ends quickly in the morning or transitions to rain. When all is said and done, we might pick up 2-4″ of snow in the city. Temperatures will be marginal at best and the snow will probably have difficulty sticking to blacktop. There is an outside chance of more than 6″ but this probability is low. As you can see from the preceding graphics, the bulk of the storm, and its center will be tracking quite far southeast of the area. Winds will be shifting towards the northwest around 20 mph and high temperatures will only be around 40ºF due to the combination of wind, clouds, and precipitation.

Wednesday – an unsettled regime continues into Wednesday with some slight chance for a couple snow showers. Mostly cloudy with high temperature in the mid-40s.

Thursday – partly sunny, high in the mid-40s.

NYC Weekend Weather – Mar 9, 2018

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This weekend, we’ll be watching for development of yet another nor’easter that could impact the region to start off next week. This would mark the third nor’easter in as many weeks, and put an exclamation point on a very active weather pattern. We also set our clocks forward with daylight saving time overnight between Saturday and Sunday. Enjoy more sun in the evenings!

Rest of today – clods and sun with a possibility for a spot flurry later in the day. High temperatures in the mid-40s.

Saturday – mostly sunny with high temperatures around average for this time of year in the mid-40s.

Sunday – another average day with sunny skies and high temperatures in the mid-40s.

Monday – things could get interesting as a developing low off the North Carolina coast works its way up the Eastern Seaboard. There’s a good deal of uncertainty at this time about the eventual storm track. Some models take this storm too far offshore to affect us, but notably the GFS has been on the western end of the forecast envelope. Some of its solutions would bring another significant storm with the possibility for more snow to the area Monday. Needless to say, this is situation that will bear monitoring over the weekend. High temperatures Monday will be impacted by the proximity of this storm. For now, forecasts call for a high around 40ºF with a chance of rain/snow.

NYC Weather Update – Mar 5, 2018

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The second week of March brings another nor’easter. The week will start off calmly with temperatures about average for this time of year. Tuesday night into Wednesday, a nor’easter will impact the region. This time around, the primary threat will be possible heavy snow rather than high winds. There are signals for yet another nor’easter next Tuesday as well!

Rest of today – decreasing clouds, high temperatures in the mid-40s with winds diminishing.

Tuesday – the veritable calm before the storm, a mostly sunny day with high temperatures in the mid-40s again.

Wednesday – a low pressure system that tracks east from the Great Lakes will spawn a secondary coastal low offshore of North Carolina. This coastal low will steadily gather strength, aided in part by the presence of an upper-level jet streak and the divergence provided within the exit region of this jet. At this time, two main camps of models have the storm tracking either close to the coast or over the 40N 70W benchmark. The former solution would mean higher precipitation amounts but more potential for mixing at the coast due to the influence of warmer marine air wrapping in. The latter solution would likely yield all snow, but with less total precipitable water. Currently, forecasters are calling for between 5-10″ of snow and a winter weather advisory is in effect.

Primary low moving east from the Great Lakes region, secondary low formation off of the coast of the NC/VA border

High temperatures should top out in the upper-30s. The main snow event would occur Wednesday afternoon and overnight. Based on the NAM and GFS ensembles, it appears as of now that the highest confidence is for a 5-6″ event. Again, this could change with a shift in the storm track, and we won’t know where the heaviest bands of snow set up until the event begins.

NAM ensemble plume forecasts for snowfall totals in LGA
GFS ensemble plumes forecast for snowfall totals at LGA

Thursday – unlike the last storm, this one will exit relatively quickly. This reduces the overall impacts for wind and coastal flooding. Thursday should be a day of improving conditions with partly sunny skies and high temperatures back in the mid-40s.

NYC Weekend Weather – Mar 2, 2018

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March arrives as a roaring lion this year with a powerful nor’easter impacting the region during the first half of the weekend. A variety of hazards from snow to high winds to coastal flooding will affect the area before this nor’easter meanders its way out to the open ocean. Behind this storm, the large scale pattern shifts and much cooler air rushes in, displacing unseasonable warmth with more average temperatures for the week to come.

Rest of today – rain and snow mixing. Little to no accumulation expected. Winds increasing from north to northeast winds 20-25 mph to 30-35 mph with gusts as high as 60 mph near the coast possible later today. Moderate coastal flooding possible over multiple tide cycles tonight, and Saturday. These tides will be higher than normal since they are falling on the full moon (spring tides). Temperatures will hold steady in the upper-30s.

Overnight, an inland low and coastal low consolidated offshore of the Northeast and the coastal low has already rapidly strengthened to a minimum pressure of 984 mb this morning. Two branches of the polar jet have phased together, providing the energy for this robust storm. As the storm continues to deepen, the pressure gradient between it and an area of high pressure over the Upper Midwest will continue to increase, leading to stronger winds. Onshore flow of these winds from the north and northeast over an extended period of time are expected to bring coastal flooding. Periods of moderate to heavy rain could lead to flooding in general. Although the cold, northwest flank of the storm as it exits to the east will support snow (with its cold conveyor belt), accumulations at the coast should be limited. This is another story inland where heavy snow is expected in the Lower Hudson Valley.

Saturday – periods of moderate to heavy rain with snow mixing in continue overnight, but should taper off by the morning. Winds will diminish from the 30 mph range with gusts up to 55 mph overnight but will remain stiff in the 20-25 mph range from the north. Much colder feel with highs in the mid-40s under partly sunny skies.

Sunday – much nicer day, winds finally abating with high temperatures in the mid-40s and mostly sunny skies.

Monday – sunny, with high temperatures in the mid-40s.

NYC Weather Update – Feb 26, 2018

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A wet and windy Sunday gives way to a week of mild and drier conditions. Temperatures this week will range about 10F above normal. While not remotely close to the record-breaking highs set last week, this should still result in pleasant conditions. Dry weather should hold up until late in the week when our next chance for rain arrives.

Rest of today – decreasing clouds with high temperatures in the mid-50s.

Tuesday – sunny, high temperatures again in the mid-50s after a colder start to they day.

Wednesday – mostly sunny with high temperatures in the mid-50s as an area of high pressure continues to dictate sensible weather in the area.

Thursday – as this high pressure moves off to the east, increasing clouds will build ahead of the next storm system. Chances for rain will increase through the day with cooler temperatures in the upper-40s.

 

NYC Weekend Weather – Feb 23, 2018

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A wet and unsettled weekend is coming up for NYC after a week that saw record-breaking warmth and large temperature swings. Back-to-back mid-latitude cyclones with their attendant warm and cold fronts will move through the area bringing a cloudy, gloomy feel, and plenty of chances for rain.

Rest of today – multiple rounds of rain showers possible through the morning and afternoon hours ahead of a warm front advancing from the southwest. Rain chances diminishing after around 6PM this evening. Overcast otherwise with a high temperature in the low-40s.

Saturday – overnight temperatures warming due to warm advection ahead of that warm front. We’ll end up in the warm sector of the first of these two mid-latitude cyclones on Saturday with high temperatures rising into the mid-upper 50s under mostly cloudy skies. Some chance for a scattered shower more likely later in the day as some post-frontal rain develops with a cold front exiting to the east.

Sunday – slightly cooler, high temperatures in the upper-40s. Another cloudy day, with rain continuing from overnight Saturday as first a warm front then a cold front moves through with this second storm system.

Monday – finally a dry day with mostly sunny skies and high temperatures in the mid-50s after this chain of storms!

NYC Weekend Weather – Feb 16, 2018

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This holiday weekend will feature some wild swings in temperature. We’ll bookend the weekend with chances for rain, but in between, we may see some decent accumulating snow. So much for an early spring.

Rest of today (Lunar New Year) – the year of the dog arrives on a cloudy day with temperatures dropping through the course of the day on the heels of a couple cold fronts pushing through. We have a break in the rain right now, but more will arrive later in the day. Winds turn to the northwest behind the front and increase in speed, bringing in a much colder air mass that will set the stage for snow on Saturday.

Saturday – much colder with temperatures topping out around 40°F after a very cold start. Increasing clouds as an area of low pressure developing off the Mid-Atlantic coast brings us the chance for accumulating snow. This coastal storm should be fairly fast mover, but forecasters think it will still bring enough precipitation to warrant a winter storm watch. The official forecasts are calling for a range of 4-8″ overnight Saturday into Sunday. Based on current forecast ensembles, I’m inclined to side with the lower end of that range and call for 4″ at best. As usual, the exact timing and track of this storm could still change a bit before the actual event. A slightly slower or slightly more northerly track would result in higher totals, and conversely a faster and more southerly track would result in only minor accumulations.

Sunday – warmer with high temperatures in the mid-40s and decreasing clouds. Whatever snow we get will begin to melt almost immediately.

Monday (President’s Day) – warmer still with high temperatures in the low-50s and chances for rain as a warm front approaches.

 

 

 

 

NYC Weather Update – Feb 12, 2018

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After a soaking rain this weekend, we start the week off with cooler, drier conditions. Temperatures ramp up going into mid-week before the next chance for precipitation hits us Thursday.

Rest of today – decreasing clouds as high pressure builds behind the cold front that passed through earlier today. High temperatures in the low-40s dropping through the course of the day.

Tuesday – mostly sunny with high temperatures in the mid-30s.

Wednesday – milder with high temperatures in the upper-40s and increasing clouds late in the day.

Thursday – a surge of warm air ahead of the next cold front to hit the area will raise temperatures well into the 50s, possibly as high as 60°F but with a chance for showers and mostly cloudy skies.