Category Archives: Weather Update

NYC Weather Update – Feb 3, 2020

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The groundhogs were unanimous in their proclamation of an early spring, but do their predictions jive with climate forecasts? Either way, the first week of February will be an active one with multiple storms impacting the area. Temperatures are forecast to start much above normal in the mid-50s, then taper down to being a touch above normal in the low-40s. Most of the precipitation that falls should be in the form of rain, though overnight periods could produce mixed precipitation.

Rest of today – Early clouds should give way to more sunny skies later in the day. High temperatures will be mild, in the mid-50s as a stationary front slowly lifts north as a warm front into the overnight hours. Overnight lows in the low-40s.

Tuesday – High temperatures in the low-50s. The warm front mentioned above stalls out, then returns as a cold front. This pattern brings the potential for some light rain showers. Overnight lows in the low-40s.

Wednesday – high pressure builds in briefly, and should give us some reprieve from rain, however, north winds will cool things off with highs in the low-40s. Overnight lows drop into the low-30s as a second, stronger storm system takes aim at the area. This one could start off as wintry mix and sleet overnight for NYC.

Thursday – any accumulation of wintry mix should get washed away as this second storm system lingers and produces rain during the course of the day Thursday. Mostly cloudy otherwise as highs climb into the low-40s. Temperatures currently forecast to remain steady for the most part overnight with onshore flow.

Are the Groundhogs Right?
Climate Prediction Center’s temperature outlooks for the second half of February and the entire month suggest that the groundhogs might be on to something – at least for the eastern part of the US (especially the southeast), where above normal temperatures are being forecast. That isn’t as much the case for the western US, as you can see below.

  • Climate Prediction Center temperature outlook for Feb 8-12
  • Climate Prediction Center temperature outlook for Feb 10-16
  • Climate Prediction Center temperature outlook for the whole month of February

NYC Weekend Weather – Jan 31, 2020

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Rain to start this weekend leads to a dramatic pattern change with anomalous ridging taking place by late in the forecast period. Temperatures throughout the period range from a few degrees above normal in the mid-40s to the mid-50s by Monday. The warmth continues into the middle of next week.

Rest of today – mostly cloudy with high temperatures in the mid-40s. A relatively weak coastal low will develop and move towards our area overnight. The best chances for rain are in the early overnight hours. Overnight lows in the mid-30s.

Saturday – rain chances will diminish quite a bit as the core of the low continues exiting to the northeast. Mostly cloudy with high temperatures in the mid-40s. Overnight lows in the the mid-30s. Some snow could mix in overnight as lingering chances for precipitation continue.

Sunday – things will dry out as the low continues to distance itself from us. Mostly sunny with high temperatures in the mid-40s. Overnight lows in the upper-30s.

Monday – the synoptic scale pattern shifts as strong ridging at the mid-levels occurs. This will translate to warm high temperatures in the mid-50s on Monday with mostly sunny skies and southerly flow. Overnight lows in the mid-40s.

NYC Weekend Weather – Jan 16, 2020

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This weekend coming up will see a dramatic contrast from last weekend’s record-breaking warmth. Temperatures during the next few days will be average to below normal. Overnight lows in the low-20s for this period. A “warm up” will happen as we enter the warm sector of a passing storm Saturday going into Sunday, but reinforcing cold air arrives to start next week.

Rest of today – partly sunny with strong northwesterly winds. Temperatures will drop from around 50ºF into the low in the mid-20s overnight. A trough extending west from a departing area of low pressure that’s bringing the strong winds may touch off some rain.

Friday – a cold, sunny day with high temperatures starting off in the low-20s and only expected to reach 30ºF under the continuing influence of northwesterly winds .

Saturday – a large storm system will move through. Temperatures starting off in the low-20s will warm into the upper-30s with southerly flow ahead of the main cold front associated with this low. Thermal profiles will support snow to start, with a light accumulation possible before temperatures warm enough at the coast to transition to all rain overnight. Overnight lows aren’t expected to move much, dropping into the mid-30s.

  • GFS model 500 mb height anomalies for 7AM Monday
  • GFS model 300 mb heights and winds for 7AM Monday – the orientation of the jets stream mirrors the position of 500 mb height anomalies

Sunday – improving conditions with high temperatures in the upper-30s and partly cloudy skies. Overnight lows in the low-20s as a second and stronger blast of Arctic air flows in behind Saturday’s storm.

NYC Weekend Weather – Jan 10, 2020

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The weather story for this weekend in NYC will be the near record-breaking warmth we’ll have with temps at or above 60°F Saturday and Sunday. A storm system sweeps through overnight going into Sunday, and should clear by Sunday afternoon. Behind this, temperatures will drop back to the upper-40s, which is still almost 10ºF above normal for this time of the year! Enjoy this rare occurrence of near record warmth that isn’t accompanied by a washout.

Rest of today – mostly cloudy with high temperatures in the low-50s. A strong area of high pressure offshore southeast of our area will be steadily pumping warm, moist air into the region. Looking at the chart below, you’ll see southerly winds blowing at large angles across temperature contours that increase going south – this is an ideal set up for persistent warm air advection and will set the stage for the warmth we see this weekend. Overnight lows in the mid-40s. With moisture advecting into the area, we could see areas of fog develop overnight.

GFS 2-meter temperature with contours and 10-meter wind barbs.

Saturday – very mild with temperatures in the low-60s. Mostly cloudy with a southerly breeze and some fog possible. Overnight lows in the mid-50s. Rain chances increase particularly late overnight going into Sunday morning.

Sunday – elevated convection could bring a rumble of thunder Sunday morning, with rain chances peaking in the early morning hours. High temperatures should remain quite mild, in the mid-60s (and possibly higher with downsloping westerly winds for a period with clearing skies, following the passage of a prefrontal trough and before a cold front closes in). Overnight lows dropping into the low-40s – which is actually still above normal for what a daytime high temperature should be this time of year.

NAM high resolution model output of 1000-500 mb thickness, surface pressure, and precipitation valid for 5AM Sunday

Monday – high temperatures similar to Friday near 50ºF, partly sunny skies. Overnight lows in the low-30s.

NYC Weather Update – Jan 7, 2020

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A quick hitting storm system brings possible light snow to the region overnight into Wednesday. High pressure builds behind this storm, with winds shifting to the northwest bringing a cool down midweek. Another storm approaches towards the end of the week. Ahead of this, temperatures surge back above normal, approaching 60°F, as southwesterly winds instigate warm air advection.

Rest of today – increasing clouds with high temperatures in the mid-40s. A coastal low passes east of the area, bringing some potential for light snow accumulations (1″ or so). Precipitation will start off as rain, though, then transition to snow briefly overnight. Overnight lows drop to around 30°F.

Weather Prediction Center surface forecast for 7PM Tuesday

Wednesday – snowfall may be enhanced by a second fast-moving arctic front. Behind this front, high pressure builds. Decreasing clouds, with winds picking up from the west then veering northwest towards overnight hours. High temperatures in the low-40s. Overnight lows will plummet quickly into the upper-20s with an Arctic air mass and northwesterly flow. Winds may gust above 30 mph during the overnight hours.

Thursday – expecting a calm, bright, sunny day with high temperatures in the low-30s, below normal for this time of year. High pressure will be moving right over us during this time. Overnight lows in the low-30s.

GFS model 500 mb height anomalies for 1AM Friday. Note the strong positive height anomaly over the Northeast, with a corresponding strong negative height anomaly over the Rockies.

Friday – high pressure will move offshore to the east, setting up warm southwesterly return flow between the western periphery of the high and an incoming storm system. High temperatures expected in the upper-40s. Temperatures should in fact warm up overnight, through the upper-40s.

NYC Weekend Weather – Jan 3, 2020

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The first weekend in the new year starts off wet and mild with a complex storm system moving over the Eastern US. Things will settle down by Sunday with a cool down coming behind this storm system. Temperatures start to rebound early next week. In general, high temperatures will trend above normal for this time of year by 5°F, topping out in the mid-40s or higher.

Rest of today – periods of drizzle during the afternoon before a second round of steadier precipitation possibly later this evening. High temperatures in the low-50s with the warming influence of westerly flow ahead of the second frontal boundary shown below. Overnight lows in the mid-40s.

Saturday – rain chances continue during Saturday. Like Friday though, the best dynamics and moisture for heavy rain seem to bypass NYC itself. This may result in more periodic rainfall on the light side. Onshore flow from the northeast should continue to keep temperatures mild, around 50°F. Overnight lows will drop into the low-30s as the storm clears and winds turn to the north and northwest.

Sunday – a mostly sunny day expected with breezy northwesterly winds. High temperatures cooler, in the low-40s. Overnight lows remain in the low-30s.

Looking ahead into next week, the above normal temperature trend for much of the Eastern US appears to persist.

Monday – high temperatures in the mid-40s with mostly sunny skies and continuing windy conditions. Overnight lows in the low-30s.

NYC Weekend Weather – Dec 20, 2019

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We’ll enjoy a prolonged period of calm weather that should take us through the week of Christmas. Temperatures should warm from below average in the 30s to above average near 50°F by the start of next week. The above average temperature trend looks like it will extend through the week. No white Christmas this year. I’ll be taking some time off and won’t have another update until closer to the new year unless something significant shapes up.

Rest of today – clear conditions with high temperatures already peaking around the low-30s. Overnight lows in the low-20s with an Arctic air mass still hanging around.

Weather Prediction Center surface forecast for 7AM Saturday

Saturday – the high pressure responsible for the cold, but calm and sunny conditions progresses east and return flow should start taking hold, with winds veering south later in the day. High temperatures should be similar to today in the low-30s. Overnight lows will be warmer than tonight in the upper-20s with milder westerly downsloping flow.

Sunday – high temperatures continue to climb into the mid-40s as more southwesterly flow takes hold. Overnight lows likewise continue a warming trend to about the freezing mark.

  • GFS model output for 500 mb vorticity, wind and heights valid 6AM Tuesday, showing a flat, zonal flow set up
  • Climate Prediction Center temperature outlook for December 25-29, calling for warmer than average temps over much of the Eastern US.

Monday – the warming continues with high temperatures forecast in the upper-40s to near 50°F. Overnight lows in the mid-30s.

Next week, it appears that we’ll be in a mostly zonal (flat westerly flow) regime at the upper-levels. That should help keep things calm and uneventful.

NYC Weather Update – Dec 17, 2019

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A soggy and messy start to the week will give way to a blast of Arctic air, leading to an extended period of below normal high temperatures only in the 30s for the most part. Temperatures do look to rebound over the weekend towards more seasonable levels. The next chance for precipitation happens Wednesday as an arctic front, harbinger of these much colder temperatures, crosses the area and brings possible snow squalls.

Rest of today – periods of rain during the day with high temperatures in the mid-30s. Rain tapers off and ends early this evening as the low pressure responsible for the stormy conditions moves off to the east. Overnight lows drop to around 30°F.

GFS model 500 mb height anomalies for Wednesday at 7PM, note the strong negative height anomaly over the Northeastern US and St. Lawrence Valley

Wednesday – should be a mostly sunny day, though as an arctic front hits us late in the day and in the early evening, a few snow squalls/snow bands could hit. These would be brief in nature but could impinge on visibility, making travel difficult. High temperatures should be similar to today in the mid-30s. Overnight lows will plummet quickly into the upper-teens with an Arctic air mass and northwesterly flow.

Thursday – northwesterly flow continues as strong Arctic high pressure builds. This will keep temperatures only in the upper-20s for highs under mostly sunny skies. Overnight lows in the low-20s.

Weather Prediction Center surface forecast for 7AM Friday

Friday – temperatures moderate a little bit, with highs in the low-30s as the high starts moving east. Overnight lows in the low-20s.

NYC Weekend Weather – Dec 13, 2019

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Mild temperatures in the mid-50s are on the way along with long duration drenching rains to start the weekend. Rain tapers off Saturday evening and conditions improve Sunday with a return to more seasonable temperatures in the 40s. A chance of wintry mix or snow is possible late Monday.

Rest of today – mostly cloudy with chances for rain increasing by the afternoon. Steady rain expected overnight. High temperatures around 50°F. Temperatures actually rise overnight with southeasterly onshore flow aiding warm advection.

  • NAM 2-meter temperature and 10-meter winds at 11PM Friday
  • NAM precipitable water for 7AM Saturday

Saturday – rain continues through the day Saturday with high temperatures peaking in the mid-50s as a warm front passes and persistent onshore flow from the southeast, backing briefly to the northeast then veering south continuously advects warmer air off the ocean to the area. Overnight lows are a different picture dropping into low-40s as winds turn to the west behind a cold front.

Sunday – as the parent low bringing this rain moves north of the area and continues gathering strength, winds will pick up from the west. This will bring cooler air to the area resulting in highs in the mid-40s under partly sunny skies. Overnight lows continue a cooling trend to about the freezing mark.

Weather Prediction Center surface forecast for 7AM Sunday

Monday – another storm system will impact the area starting late in the day. Temperatures will be cold, topping out in the mid-30s. Precipitation starting late on Monday should begin as snow or a wintry mix given the currently forecast temperature profile. As is the case going into Saturday, a change in wind direction accompanying a warm front should help temperatures actually rise overnight into the upper-30s, allowing precipitation to transition to rain.

NYC Weather Update – Dec 10, 2019

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Very mild air at the start of the week gives way to a much colder air mass as a cold front finally sweeps through later today. Drenching rains from yesterday should give way to lighter precipitation today, however, with temperatures dropping we could see some light accumulating snow by Wednesday morning. Temperatures will rebound into normal to above normal ranges after a dip into high temperatures in the 30s mid-week.

Rest of today – mostly cloudy with high temperatures peaking in the upper-50s. Long duration southerly flow ahead of an slow moving cold front has brought in a much warmer air mass to the region. Rain chances pick up in the afternoon with the front nearing and continues into the overnight hours with a couple breaks. Behind this front, much colder air rushes in with overnight lows dropping to near freezing. With precipitation continuing, this should allow for a transition to all snow. Light accumulation of around 1″ is possible, though not a lock since the ground has been quite warm for a couple days now with all the rain.

Weather Prediction Center probabilistic forecast for 1″+ accumulation of snow by 7AM Wednesday

Wednesday – snow winding down in the morning. High temperatures in the upper-30s, about 10°F below normal for this time of year. Skies clearing later in the day with overnight lows in the mid-20s.

Thursday – with a chilly start to the day, high temperatures will have a tough time getting out of the low-30s. Mostly sunny otherwise. Overnight lows in the upper-20s.

Friday – high pressure that fills in behind the cold front passing Tuesday and giving us the sunny weather Thursday eventually moves off to the northeast. Onshore flow should help moderate highs into the upper-40s. Rain chances increase with the next storm system – a possible coastal low – moving up overnight. Overnight lows in the mid-40s.