All posts by Lei Zhao

NYC Weekend Weather – Apr 2, 2020

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A retrograding low will bring increasing clouds, wind and rain to end the week. This low will be blocked from moving east until late Friday. High pressure will move in Saturday and should dry things out, and bring more sun. A weak cold front is forecast to pass through Sunday. Some rain will be possible with this frontal passage. Temperatures during this period should remain at or above normal for this period in the mid-50s.

Rest of today – increasing clouds with a low retrograding west towards the area. High temperatures in the mid-50s. Winds will pick up also as the pressure gradient builds between the retrograding low and high pressure to the west. Overnight lows should be around the mid-40s.

Friday – chances for rain, mostly in the morning hours, with high temperatures in the mid-50s under mostly cloudy skies. Rain chances will diminish as this low finally pulls off to the south. Overnight lows again in the mid-40s.

  • Weather Prediction center surface forecast for 2AM Friday
  • GFS model 500 mb height, vorticity and wind forecast valid 10AM Thursday. Note the presence of the closed upper low offshore of the Northeast, with an omega blocking pattern over the eastern Atlantic (two lows, with a ridge in between, literally looks like the Greek letter for omega)

Saturday – as high pressure moves in, we’ll see a better day with partly to perhaps mostly sunny skies and high temperatures in the upper-50s. Overnight lows will be in the mid-40s.

Sunday – a weakening cold front may bring a chance for showers, but ahead of this, temperatures will be mild in the upper-50s. Overnight lows will warm into the mid-40s.

NYC Weather Update – Mar 23, 2020

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It’ll be a cloudy start to the week with possible thunderstorms later today. Rain chances continue Tuesday with a surface low in our vicinity. Once this low moves off, our weather calms Wednesday. High pressure builds in Thursday and should bring us mostly sunny skies. High temperatures start off slightly below normal in low-50s with clouds and rain, and will warm into normal ranges in the mid-50s later on.

Rest of today – energy from an upper level low will support development of a surface low around its base. Surface troughs from this low may touch off some isolated showers and thunderstorms later this afternoon with the aid of a cold pool aloft (increasing lapse rates and increasing instability). Best chances for this activity will be north of the city. High temperatures in the mid-50s with clouds and rain. Overnight lows in the low-40s.

  • GOES East Geo Color satellite image. You can see the large area of cloudiness associated with the upper level low
  • High resolution rapid refresh simulated radar showing the possibility for some convective activity associated with a cold pool later this afternoon around 5PM

Tuesday – this surface low will help move a backdoor cold front through, bringing cool, damp, northeasterly flow to the area. With this air mass, we’re only expecting high temperatures in the upper-40s. Rain chances continue with the low in our vicinity. Overnight lows in the upper-30s.

Wednesday – the low affecting our weather to open the week finally moves off. We’ll get a dry day with diminishing clouds and high temperatures around 50°F. Overnight lows around 40°F.

Thursday – high pressure builds and brings us a mostly sunny day. High temperatures rebound into the mid-50s in response. Overnight lows in the mid-40s.

NYC Weekend Weather – Mar 26, 2020

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The active weather pattern we’ve seen so far this week with alternating days of sun and rain continues with two more storms coming for the end of the week into the weekend. This time around, the rainy days will outnumber the sunny ones. We will start off with a beautiful Thursday before a weaker storm impacts the area tomorrow. A more significant system will move through later Saturday into Sunday. Temperatures during this time will range around normal to above normal in the 50s.

Rest of today – high pressure will be in control of the weather today, yielding a sunny day with temperatures steadily rising into the upper-50s. Overnight lows should be around the mid-40s.

Weather Prediction Center surface forecast for 8AM Friday

Friday – clouds will build overnight into the day and by the morning hours a weak area of low pressure will be moving through the area. We can expect some light rain with this system in the morning, rather than a full day washout. Clouds will remain through the rest of the day even after the system clears and rain stops. High temperatures around 60°F. Overnight lows will be in the low-40s as a result of radiational cooling as high pressure briefly builds.

Saturday – with high pressure positioned to our north to start, northeasterly flow will keep temperatures cool in the low-50s. A stronger storm system with origins in the lee of the Rockies will be moving towards us throughout the day. A warm front will slowly move up from the south bringing a steady rain ahead of it. Overnight lows will be in the mid-40s as rain continues.

GFS 500 mb height and relative vorticity valid 8PM Sunday. Note the presence of a closed 500 mb low over Michigan and southern Ontario generating lots of positive voriticity around it. This will provide divergence and lift at the upper levels to support the storm hitting us Sunday.

Sunday – With the warm front making its way through and flow turning towards the south/southwest, temperatures should rise to around 60°F. However, rain chances are expected to continue throughout the course of the day before tapering off overnight. Overnight lows will warm into the upper-40s.

NYC Weather Update – Mar 23, 2020

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We have an active weather pattern with two storms moving through NYC this first full week of spring. A nor’easter will pass offshore today, bringing mixed precipitation early then cold rain later. We get a lull Tuesday with temperatures rebounding into the mid-50s, before a second low hits Wednesday. This will bring another round of cold rain with temps back in the mid-40s. Temperatures rebound again Thursday after this second storm.

Rest of today – some light mixed precipitation has already moved through the region this morning. A second round of more consistent, moderate precipitation should hit around lunch. High temperatures only in the mid-40s. Overnight lows around 40°F.

  • High resolution rapid refresh simulated radar for 1PM Monday
  • Weather Prediction Center surface forecast for 8PM Monday

Tuesday – the nor’easter pulls away to the northeast and we get a brief period of calm with weak high pressure building in. Partly sunny skies expected with highs in the upper-50s. Overnight lows in the low-40s with rain chances picking up towards Wednesday morning.

Wednesday – a second storm system moves up from the south. This will bring us another round of cold rain, with highs back in the mid-40s. Overnight lows around 40°F.

GFS model 500 mb height and relative vorticity valid 2PM Wednesday. A shortwave trough is evident over the Northeast, providing upper-level divergence for the second storm to hit this week.

Thursday – similar to Tuesday with things drying out. Partly sunny skies with high temperatures in the mid-50s. Overnight lows in the mid-40s.

NYC Weather Update – Mar 9, 2020

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Near record warmth to start the week in the upper-60s to low-70s. A summer-like pattern with a strong high pressure center over the western Atlantic will keep warm, southerly winds coming our way. A cold front will approach Tuesday bringing chances for rain. Temperatures remain above normal in the 50s for the remainder of the week.

Rest of today – very warm with mostly sunny skies and highs in the upper-60s to low-70s. The record high for today at LGA is 75°F so this is definitely abnormally warm. Strong ridging over the western Atlantic is leading to very warm southerly flow coming our way. Overnight lows in the upper-40s.

Tuesday – an approaching cold front will bring clouds and some chances for rain especially later in the day. High temperatures will still be quite mild in the low-60s with continuing southerly flow ahead of the frontal passage. Overnight lows should be in the mid-40s.

Wednesday – behind the cold front, temperatures will dip into into the mid-50s, but that’s still 7-10ºF above normal for this time of year. Skies should also clear up. Overnight lows will drop into the low-40s.

Climate Prediction Center temperature outlook for Mar 14-18, showing the above average temperature trend continuing in many parts of the Eastern US while below normal temperatures are likely out west.

Thursday – similar day to Wednesday with high temperatures in the mid-50s, but with potentially more clouds as the next storm system approaches. Overnight lows in the low-40s.

NYC Weekend Weather – Mar 6, 2020

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This weekend starts of with a storm system passing well southeast of NYC Friday into Saturday. The periphery of this low offshore, a weakening secondary low tracking from the Great Lakes, as well as a weak inverted trough pivoting through will still give us a chance for rain later today and overnight into Saturday. Behind this storm, temperatures will cool to seasonable levels in the mid-40s. However, high pressure will build and quickly move southeast. The flow will turn southerly and bring a big warm up to start week in the 60s.

Rest of today – clouds have already worked their way into the are ahead of a secondary low moving east. High temperatures today should peak in the upper-40s. Rain chances increase in the afternoon as bands of precipitation develop and start pivoting around a rapidly strengthening offshore low. The secondary low will transfer energy to this offshore low and eventually be absorbed. A brief period of wet snow could happen overnight, but no accumulation is expected. Overnight lows should be around the mid-30s.

Weather Prediction Center surface forecast for 7PM Friday

Saturday – clouds should clear with high pressure starting to build in. Temperatures won’t be that much cooler behind this storm, rebounding into the mid-40s, but it will be cooler than we’ve been used to this week. The pressure gradient between the incoming high pressure and departing offshore storm should allow for some brisk northerly winds. As the high pressure continues moving overhead, winds should calm and allow for a mostly clear overnight. Overnight lows will be in the low-30s as a result of good radiational cooling from these conditions.

Sunday – by this time, the high pressure should continue to track southeast. In response, winds will being shifting to the southwest, bringing a much warmer air mass back to the region. High temperatures will likely respond by shooting back into the upper-50s. Overnight lows will be considerably warmer, in the low-40s. We jump ahead an hour as daylight saving time starts.

  • GFS model 2 meter above ground temperatures, 10 meter above ground winds for 2PM Monday
  • GFS model surface pressure and 10 meter above ground winds for 2PM Monday

Monday – the prolonged period of southerly flow as the high pressure keeps moving off to the southeast with plenty of sun at an increasing angle should result in high temperatures well into the 60s, mid-upper 60s possibly! Overnight lows will continue warming into the mid-40s.

NYC Weather Update – Mar 3, 2020

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First half of this week features much above average temps in the upper-50s slowly dropping to the low-50s after mid-week. A passing storm system could bring showers and isolated thunderstorms overnight tonight. Temperatures remain mild until later in the week. Another chance for rain/snow is possible overnight Friday into Saturday as another storm system passes by.

Rest of today – very mild, high temperatures in the upper-50s with the area in the warm sector of a low pressure system centered over northern Quebec. A secondary low will bring another reinforcing warm front through before the trailing cold front finally swings through. Rain chances increase towards the afternoon with a batch of rain possible around 3PM. A second, stronger round of rain is possible around 10PM. Overnight lows in the mid-40s.

Weather Prediction Center Surface forecast for 1AM Wednesday

Wednesday – despite the passage of a cold front, the air mass behind the front won’t be that much colder than today’s. Furthermore, downsloping westerly flow should keep things on the mild side with high temperatures expected in the mid-50s under mostly sunny skies. Overnight lows will dip into the upper-30s.

Thursday – another nice day with high temperatures still above normal in the low-50s, with mostly sunny skies. Overnight lows in the upper-30s.

Climate Prediction Center temperature outlook for Mar 8-12, showing a warm up yet again next week.

Friday – clouds build as a couple storm systems start making their way towards our area. Cloud cover and chances for rain during the day will keep temperatures closer to normal in the mid-40s. Overnight lows in the low-30s could allow for some rain to mix with snow before the storms clear our area.

NYC Weather Update – Feb 24, 2020

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Mild temperatures from this weekend carry over into the beginning of this week. High temperatures will remain in the 50s, well above normal, until the second half of the week. A couple storm systems will impact the area bringing rain, as well as a cool down in temperatures to end the week. The upcoming weekend will see temperatures drop to below normal levels with highs only in the 30s.

Rest of today – very mild, high temperatures in the upper-50s with persistent southerly flow. Increasing clouds towards the overnight hours. Rain chances increase towards day break with overnight lows in the low-40s.

Weather Prediction Center surface forecast for 7AM Tuesday

Tuesday – rain chances continue to increase as the storm above moves closer. High temperatures top out in the low-50s with mostly cloudy skies and rain chances throughout the day. Overnight lows in the low-40s with rain chances continuing.

Wednesday – rain starts to diminish but is still possible with this storm system being fairly slow to clear the area. High temperatures remain in the low-50s. Overnight lows in the mid-40s with one more slug of rain moving through.

GFS mean sea level pressure, and 10 meter above ground winds for 11PM Thursday

Thursday – clouds start to break and the rain finally clears the region. Winds will pick up as high pressure builds to the west with low pressure exiting east, creating the right pressure gradient depicted above. High temperatures dropping into the upper-40s. Overnight lows in the low-30s with cooler northwesterly winds.

NYC Weather Update – Feb 18, 2020

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Cloudy day with light rain possible to start the forecast period. Skies clear for the remainder of the week behind this storm as high pressure builds. Temperatures will dip into the 30s for a brief stretch as well before rebounding back to above normal levels in the mid to upper-40s. Looking ahead into next week, above normal temperature trend is very likely to continue.

Rest of today – Light rain possible today with a warm front passing nearby and a cold front following behind that. However, the bulk of the moisture with this storm system appears to be focused south of the region, so not expecting any heavy rainfall totals. Otherwise, mostly cloudy with highs in the upper-40s. Overnight lows around 40°F with gradual clearing towards daybreak.

Weather Prediction Center surface forecast for 7PM Tuesday.

Wednesday – mostly sunny with high temperatures in the low-40s, about average for this time of year. Winds turn to the northwest behind the cold front, which will facilitate cold air advection. Overnight lows in the mid-20s as a result with high pressure building.

Thursday – cold start to the day will likewise mean a cooler high temperature in the mid-30s with mostly sunny skies. High pressure continues to exert its influence. Overnight lows once again quite cold in the low-20s.

Climate Prediction Center temperature outlook for Feb 23-27, showing greater than 90% probability of above normal temperatures for much of the Northeast.

Friday – this pattern continues with high temperatures Friday reaching into the mid-30s under mostly sunny skies. Overnight Friday into Saturday, the high pressure finally starts moving east in earnest. Lows will range in the upper-20s.

NYC Weather Update – Feb 11, 2020

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Light rain today will fall today. This will be followed by a brief spell of sunny skies and calm weather Wednesday. Another storm system impacts the area Thursday, bringing some mixed precipitation and rain. On the back side of this system, a drastic drop in temperatures will take place going into the weekend. This will be the coldest air mass we’ve seen in many weeks with lows in the teens.

Rest of today – Light rain in the morning and cloudy. High temperatures in the upper-40s. Overnight lows in the mid-30s with gradual clearing.

Weather Prediction Center surface forecast for 7AM Wednesday

Wednesday – high pressure briefly builds in with high temperatures in the mid-40s. Mixed precipitation could begin later in the day as the next storm system approaches. Overnight lows in the upper-30s with increasing mixed precipitation then transitions to rain.

Thursday – A warm up takes place with a warm front and southerly flow overnight. High temperatures reach into the mid-50s with rain ending in the morning/early afternoon. Much cooler temperatures overnight with lows around 30°F once the cold front of this storm system moves through.

GFS model 1000-500 mb precipitation and thickness valid 5PM Friday. Note the large area of Canadian high pressure centered over Indiana.

Friday – strong Canadian high pressure builds behind the cold front mentioned above. A much colder air mass will accompany this high, with temperatures Friday only in the low-30s. The real chill takes place overnight, with lows dropping into the mid-teens as Arctic air keeps pumping in!