Category Archives: Storms

NYC Weekend Weather – Jan 29, 2021

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An arctic chill with bitterly cold winds kicks off the weekend as strong high pressure moves in. Overnight lows in the teens and high temperatures in the 20s will range 10-15ºF below normal for this time of year. This cold air could set the stage for a nor’easter bringing significant snowfall to the region, with totals > 6″ possible Monday into Tuesday. As usual, track details on this storm will be pivotal, and are not clear at this time.

Rest of today – mostly clear, cold, and windy with high temperatures in the low-20s. A strong arctic high and a departing low will create a tight pressure gradient that ushers in stiff northwesterly winds 20-25 mph. Wind chills will hover around 0ºF. Overnight temperatures drop into the mid-teens with wind chills likewise dropping below zero.

Weather Prediction Center surface forecast for 7AM Saturday. A strong area of high pressure is parked over much of the Eastern US.

Saturday – winds abate with high pressure moving more directly overhead. Sunny, but still cold with high temperatures around 30ºF. Overnight lows will be in the upper-teens under increasing cloud cover.

Sunday – mostly cloudy as the next storm system starts to work in. High temperatures around 30ºF. Overnight lows in the upper-20s with the possibility of snow developing overnight into Monday morning.

  • GFS model total snowfall accumulation as of 7AM Tuesday
  • ECMWF model total snowfall accumulation as of 7AM Tuesday
  • UKMET model total snowfall accumulation as of 7AM Tuesday

Monday – stiff northeasterly winds developing along with snow. High temperatures in the low-30s. The storm possibly bringing us significant snow came ashore over the west coast yesterday and will be transiting the country the next couple days. It is eventually forecast to spawn a coastal low, bringing a nor’easter into our region. Even though cold air will precede this storm, offshore waters are still mild, in the low 40s-50s, and with the storm likely to bring southerly/northeasterly flow at the outset, we could see enough warming to mix to rain at the coast. Storm track and strength will be vital to the eventual snowfall totals. Models seem to signal a very tight banding feature bringing heavy snow – you’ve heard this before but these bands are notoriously difficult to pinpoint even a day ahead of the event. If the optimal scenario plays out, we could see a storm with similar or possibly bigger totals than the one in December. Overnight lows Monday shouldn’t budge much, in the low-30s, with some warm advection associated with portions of the storm.

NYC Weekend Weather – Jan 22, 2021

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A cold and breezy start to the weekend with a cold front ushering in below average temperatures mostly in the mid-30s. High pressure builds and keeps things dry during the weekend. However, the upper-level pattern shifts to allow a shortwave trough to push through early next week, leading to a storm that could bring some accumulating snow overnight Monday into Tuesday.

Rest of today – partly cloudy with high temperatures in the low-40s. A moisture-starved cold front will work its way through the region. The main impact of this front will be to induce a shift in winds to the northwest, and trigger some decent cold air advection. This will lead to overnight temperatures plummeting into the mid-upper 20s.

Weather Prediction Center surface forecast for 7AM Saturday

Saturday – high pressure builds in behind the cold front, giving us a mostly sunny day. This high pressure and a low off to the northeast over the Canadian Maritimes will lead to a fairly tight pressure gradient, and the result should be breezy winds from the northwest, sustained in the range of 15-20 mph at least. So despite the sun, the cold start to the day will lead to temperatures in the low-30s and a much colder feel with wind chills around 20ºF. Overnight lows will be the coldest in quite some time, in the low-20s.

Sunday – windy conditions continue at least part of the day with high temperatures in the mid-30s. Once the center of the high moves over us, winds should subside. Overnight lows in the mid-20s with clouds building in.

GFS model 500 mb height and vorticity animated loop valid 7PM Sunday through 7PM Monday, showing a de-amplifying shortwave trough ejecting from the southwest towards our region.

Monday – as the high pressure eventually moves off, a shortwave trough will be progressing towards our region. The accompanying surface low will bring mostly cloudy skies. Temperatures should peak in the mid-30s. Overnight, the storm is positioned to possibly bring us some light accumulating snow. Currently, it’s hard to pin down a total, but the following images from GFS and ECMWF models suggest something on the order of 3-5″ is possible. Low temperatures in the upper-20s should support all snow during this event, so storm track will be key here.

  • GFS model 24 hour snowfall total ending 1AM Wednesday
  • ECMWF model total snowfall ending 1AM Wednesday

NYC Weekend Weather – Jan 15, 2021

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Our extended period of calm weather comes to an abrupt end this weekend. A low pressure system with its attendant vigorous cold front sweeps through overnight bringing moderate to heavy rain. We could see as much as 1-1.5″ of rain with this event. Behind this front, windy conditions prevail Sunday as the low exits but continues to deepen. Next week, we’ll see a return to normal temps around 40ºF.

Rest of today – mostly cloudy with high temperatures in the mid-40s. Rain chances increase as the storm system approaches us. Warm air advection associated with the warm front of this storm will result in little movement on overnight lows, which will hover in the mid-40s. Moderate to heavy rain is likely after 9PM tonight and into the overnight hours.

High Resolution Rapid Refresh simulated radar for 1AM Saturday.

Saturday – as the storm pulls off to the east in the morning, rain chances should decrease, ending by noon. Isolated wrap around showers are possible. Temperatures will decrease during the day with cold air advection, dropping into the low-40s. Overnight lows in the mid-30s as skies clear.

Sunday – mostly sunny with high temperatures in the low-40s. Breezy with west winds in the 15-20 mph range and stronger gusts due to a large pressure gradient around the exiting and intensifying low. Overnight lows in the mid-30s.

Weather Prediction Center surface forecast for 7AM Sunday. The low affecting us this weekend is seen in the upper right corner, with a tight clustering of isobars around it, indicating a large pressure gradient.

Monday – an upper level low will affect the area pushing a cold front through our region, but this front should be moisture starved. Partly sunny with highs around 40ºF. Overnight lows around 30ºF.

NYC Weather Update – Dec 29, 2020

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Messy weather ahead going into the New Years holiday for NYC. We start with high pressure moving overhead. This then gives way to a frontal system tomorrow night. After a brief lull, another storm, similar in some ways to the Christmas storm comes in Friday. Both these precipitation will be rain in the city. Temperatures during this period will generally be above normal in the 40s, warming into the mid-upper 40s.

Rest of today – partly cloudy with high temperatures around 40ºF. Clouds will be streaming in from the northwest, originating from the Great Lakes as lake effect snow showers. These clouds will tend to thin out as northwest flow downslopes dries out across the higher terrain north and west of the city. This northwest flow could also result in some strong wind gusts. With strong high pressure forecast to move nearly directly overhead tonight, winds should calm with skies becoming mostly clear. This will favor good radiational cooling, leading to cold overnight lows in the mid-20s.

GOES Geostationary Satellite visible imagery this morning showing clouds streaming off the surface of the Great Lakes towards the East Coast.

Wednesday – partly cloudy with high temperatures again around 40ºF. Overnight, a warm front passes, followed by a cold front. This will result in an increase in temperatures overnight from the mid-30s as well as rain.

Thursday – a mild day despite the passage of the cold front mentioned above, with forecasters noting the air mass behind the front being of milder Pacific origin. High temperatures around 50ºF. Rain chances should diminish quickly after the morning passage of the cold front. The respite will not last too long as the next storm system follows up quickly. Overnight temperatures dropping into the low-30s.

  • ECMWF “Euro” model 24 hour quantitative precipitation forecast ending 7AM Saturday, about .70″.
  • GFS model 24 hour quantitative precipitation forecast ending 7AM Saturday, close to 1″.

Friday – high temperatures in the mid-40s with another storm system approaching. Rain chances increase going into the overnight hours. This storm, like the Christmas storm, is expected to deliver some moderate to heavy rain. However, since it’s forecast to be weaker overall, the winds and precipitation totals shouldn’t be nearly as robust as the last storm. Overnight should shape up to be similar to Wednesday, where temperatures may actually increase into the upper-40s with the passage of a warm front and corresponding warm air advection.

NYC Weather Update – Dec 14, 2020

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A quick hitting storm passes south of the city today bringing some rain and mixed precipitation, with no accumulating snow expected. Colder temperatures then take hold in the mid-30s behind this storm Tuesday as a strong area of high pressure builds over Quebec. This sets the stage for a potentially significant snowstorm developing Wednesday into Thursday with 8″+ totals possible along the I-95 corridor (with higher amounts north and west). However, there is still a good deal of uncertainty with the eventual track of this storm that could result in large differences in outcomes.

Rest of today – temperatures dropping through the low-40s into the 30s with mostly cloudy skies and a steady, chilly rain, possibly mixing with some wintry precipitation. No accumulation is expected. Overnight lows around the freezing mark with precipitation ending as high pressure begins building in.

Weather Prediction Center surface forecast for 1PM Monday. An area of low pressure is seen exiting the east coast, bringing us a period of rain and possible mixed precipitation, with snow further inland.

Tuesday – proverbial calm before the storm as high pressure dominates, giving us a mostly sunny day with high temperatures around 40ºF. Overnight lows again in the upper-20s with cold northerly winds flowing around the east side of this high.

Wednesday – high pressure yields to a developing coastal storm. Partly sunny to start with increasing clouds. High temperatures in the mid-30s. Overnight lows drop into the mid-20s. The big story is the potential for a significant snowstorm with accumulations possibly over 8″. GFS and the Euro model have come into agreement for much higher totals, 14-15″. However, NAM shows a warmer scenario with warmer air working further north, thus cutting into overall totals (only 7″). It’s also possible that the low tracks close enough to shore that we end up with a good deal of rain mixing in at the coast, cutting snow totals even further.

Part of the energy fueling this storm is coming all the way from a shortwave with origins over the Pacific Ocean. This has only just made landfall in the US today. As this energy gets sampled by upstream soundings (weather balloon launches) and other means, the forecast models should get a better sense for how this storm will evolve. At this time, there’s enough uncertainty in the forecast to still not buy into any specific totals. If you look below, you can see there’s a lot of spread in the models in terms of the track of this storm. This then translates to a wide range in ensemble forecast totals. In addition, with a coastal storm like this, where there’s a lack of deep, Arctic cold air ahead of the storm, there’s a sharp gradient between areas where the event would be all snow vs. a mixed event. If you see the 24 hour probabilities of > 8″ accumulation, you can see that a 50 mile shift in the storm track further south and east would give us much higher chances for big snowfall totals, while a shift the other way could result in a bust on snow totals. Suffice to say, this storm will bear close monitoring today and tomorrow as more data comes in and models have a chance to digest it.

  • ECMWF “Euro” model surface pressure, precipitation and type for 1AM Thursday
  • ECMWF total snow accumulation at 7AM Thursday, showing 14″ of snow in NYC.
  • GFS model surface pressure, precipitation and type for 1AM Thursday
  • GFS total snow accumulation at 7AM Thursday, showing 15″ of snow in NYC.
  • NAM model surface pressure, precipitation and type for 1AM Thursday
  • NAM total snow accumulation at 7AM Thursday, showing 7″ of snow in NYC.
  • Weather Prediction Center probabilities of > 8″ total accumulation in 24 hours leading up to 7AM Thursday
  • Weather Prediction Center storm track forecasts, note the cluster of blue crosses associated with a surface low near the Delmarva Peninsula. This is the storm that could bring us snow.
  • GEFs ensemble model plumes showing a huge range of possible snowfall totals at LGA during this storm. The mean is 7.83″.

Thursday – depending on the speed and track of the storm, we could see precipitation lingering into the morning hours, with additional accumulation possible. Highs should hover around the freezing mark. Overnight lows drop into the mid-20s with reinforcing cold air advection on the backside of the departing storm.

NYC Weather Update – Jun 22, 2020

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The first official week of summer brings us warm temperatures in the upper-80s (low-90s interior). Early in the week, there will be chances each day for scattered showers and thunderstorms, particularly over inland areas. South facing shorelines should enjoy cooler temperatures with the possibility of sea breezes developign. A cold front passes Wednesday, bringing chances for more organized precipitation. Behind this, skies should clear up but temps remain warm.

Rest of today – mostly sunny with high temperatures around 90ºF. Chance for scattered showers and thunderstorms in the afternoon. Coverage would be spotty at best but with plenty of moisture available, any storms could produce heavy rain. Overnight lows around 70ºF.

Weather Prediction Center surface forecast for 8PM Tuesday.

Tuesday – similar to today, with high temperatures peaking near 90ºF and mostly sunny skies to start, then more clouds and some scattered showers and thunderstorms possible later in the afternoon. Overnight lows in the low-70s.

Wednesday – a cold front approaches from the west and brings us a better chance for organized showers and thunderstorms later in the day. These storms may be weakening as they hit the area if they arrive late in the day with sunlight diminishing. High temperatures again around 90ºF. Overnight lows in the low-70s.

GFS model 500 mb height, relative velocity, valid for 2PM Thursday.

Thursday – behind the cold front, skies should clear up as high pressure builds. However, temperatures will remain warm in the mid-80s with downsloping westerly winds. Overnight lows around 70ºF.

NYC Weather Update – Jun 8, 2020

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High pressure will be the main story this week, providing plenty of sun and summery weather. A chance for rain comes later with the extratropical remnants of Tropical Depression Cristobal. The timing of this is rain not entirely certain, but it looks like this will be Thursday for now. Temperatures this week should be ranging slightly above normal with high temperatures in the low-mid 80s.

Rest of today – mostly sunny with high temperatures around 80ºF. Just a beautiful day with comfortable temperatures and low humidity. Overnight lows in the mid-60s.

Weather Prediction Center surface forecast for 8AM Tuesday.

Tuesday – temperatures warm up into the mid-80s with lots of sun as the high pressure center shifts gradually off to the southeast and we see southerly flow take hold. Humidity still overall not that bad, so it shouldn’t feel muggy. Overnight lows in the upper-60s.

Wednesday – high temperatures back down into the low-80s though clouds could be on the increase. Overnight lows in the upper-60s with rain chances possibly increasing.

GOES visible satellite loop of Tropical Depression Cristobal the morning of June 8, 2020, after it made landfall as a tropical storm this weekend over Louisiana

Thursday – a cold front associated with the extratropical remnants of Tropical Depression Cristobal could bring some rain and thunderstorms to the area. Otherwise, mostly cloudy with high temperatures in the low-80s. Overnight lows in the upper-60s.

NYC Weather Update – Jun 2, 2020

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A stretch of slightly above normal temperatures in the low-80s is in store for us as we kick off the month of June. Temperatures and humidity will pick up noticeably tomorrow with a warm front passing through. Some thunderstorms are possible with the trailing cold front. Weather improves Thursday then rain chances increase again later in the week. The tropics have been active, too, with Tropical Depression Three forming in the Bay of Campeche.

Rest of today – mostly cloudy with high temperatures in the mid-70s. Overnight lows in the low-50s with a chance of showers developing.

Weather Prediction Center surface forecast for 8AM Wednesday.

Wednesday – rain chances continue into the day Wednesday with a warm front passing through early in the day. Temperatures will warm up into the low-80s in response to southerly flow. Some break in the clouds possible between the warm front and a trailing cold front. Clouds increase again later with this cold front. Some thunderstorms could pop up. Overnight lows in the mid-60s with rain chances diminishing and clouds clearing.

Thursday – high pressure briefly builds in with temperatures in the low-80s and mostly sunny skies. Overnight lows in the mid-60s with rain chances increasing again as another frontal system moves in.

Friday – mostly sunny with high temperatures in the low-80s. Chances for scattered showers and thunderstorms in the afternoon. Overnight lows in the upper-60s.

In the tropics

The 2020 Atlantic Hurricane Season is forecast to be an active one, and is living up to this forecast so far. A tropical depression formed yesterday in the Bay of Campeche, and if it organizes into a named tropical storm before Thursday, it will break a record for the earliest time for a third named storm to form. For now, this storm poses little risk for the US, but will bring heavy rain to a wide swath of southeastern Mexico and Central America. Later in the forecast period, this storm could track out into the open waters of the Gulf of Mexico and head towards the Gulf Coast.

GOES visible satellite loop of Tropical Depression Three in the Bay of Campeche this morning.

NYC Weather Update – May 18, 2020

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While it looked earlier this weekend that this would be a rainy week, it now appears that strong high pressure will keep two storm systems largely at bay. One of these will be the post-tropical remnants of Tropical Storm Arthur that formed this weekend. The tradeoff is that this high of Canadian origin will bring cooler than normal temperatures in the 60s. This pattern breaks up by late this week, yielding warmer temperatures in the 70s by this weekend.

Rest of today – mostly cloudy though no rain expected with high temperatures around 70ºF. Clouds from the two storm systems below will remain throughout the day. Overnight lows in the mid-50s as skies gradually clear.

In this GOES geocolor visible satellite loop, you can clearly see two centers of circulation – one over the Midwest associated with a maturing mid-latitude cyclone, and one over the Atlantic – Tropical Storm Arthur.
Weather Prediction Center surface forecast for 8AM Tuesday.

Tuesday – high pressure continues building, and blocks the northward and northeastward progress of both storms. Temperatures cool into the mid-60s despite more sun with northeasterly onshore winds. Tropical Storm Arthur is expected to have undergone extratropical transition by this point, and potentially strengthened due to baroclinic forcing. The proximity of this storm to the high pressure will produce a tight pressure gradient resulting in stronger winds during the day Tuesday. Overnight around 50ºF.

Wednesday – high pressure remains in place, producing sunny skies. High temperatures still cooler than normal in the mid-60s. Overnight lows in the mid-40s.

Climate Prediction Center temperature outlook for May 23-27: temperatures appear ready to rebound going into this weekend to above normal levels.

Thursday – sunny with high temperatures in the mid-60s still. Overnight lows in the low-50s.

NYC Weekend Weather – Apr 9, 2020

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We have a stormy start to the forecast period with the Storm Prediction Center putting us under a slight risk for severe weather this afternoon. Behind this storm, windy conditions will prevail Friday with the pressure gradient tightening between an incoming high pressure and the departing low. This pressure gradient eases Saturday as high pressure moves more directly overhead. Decent weather continues Sunday before another storm rolls in Monday. Above normal temperatures for Thursday in the low-60s. Temperatures drop below normal in low-50s this weekend before picking up Monday into the upper-60s.

Rest of today – lighter stratiform rain in the morning hours with a warm front moving through. This will be followed up by a possible round of strong to severe thunderstorms in the afternoon hours (most likely around 1-2PM). The primary risk for severe weather comes from the potential for damaging wind gusts, with very fast winds aloft potentially mixing down to the surface. High temperatures in the low-60s. Overnight lows around 40ºF as gusty winds bring in strong cold air advection. See this detailed forecast for more info about today.

Storm Prediction Center convective outlook for Thursday, showing us in a slight risk area for severe weather later today.

Friday – despite a high in the low-50s, strong winds around a deepening low will make it feel significantly cooler. Clouds should gradually diminish during the day. Overnight lows cool, in the upper-30s.

Weather Prediction center surface forecast for 8AM Friday. A strong low pressure cetner is indicated tracking northeast out of Maine.

Saturday – winds ease as an area of high pressure moves more directly over us. High temperatures should range in the mid-50s with plenty of sun. Overnight lows will be in the mid-40s.

Sunday – clouds increasing with high temperatures in the upper-50s. Overnight lows will warm into the low-50s.