Category Archives: Storms

NYC Weather Update – Nov 17, 2014

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The main headline for weather this week will be bitterly cold temperatures that are highly abnormal (in fact, possibly record setting) for this time of the year. We’re talking lows on Wednesday morning in the low 20s in the city, teens and even single digits north and west, and wind chill values in the single digits with a stiff west wind. The cold air finally breaks this weekend, though, with the arrival of a storm system that will push warm air in from the southwest.

Tuesday – high temperatures tomorrow will only be in the mid-30s under sunny skies following the passage of a cold front that’s currently right at our doorstep. Behind this front, breezy west winds between 20-25mph will pick up with wind gusts as high as 35mph. That will translate to wind chill values in the 20s for most of the day tomorrow.

Wednesday – we could break some records for lowest maximum and minimum temperatures Wednesday. Lows overnight Tuesday into Wednesday morning may only be in the low 20s, and with a west wind still kicking around 20mph, wind chill values will be in the low teens by daybreak. Temperatures won’t rebound much during the day either, with a high temperature forecast to be barely at the freezing mark.

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Thursday – temperatures should rebound considerably with the passage of a warm front late Wednesday and prior to another cold front passing later Thursday. High temperatures should reach the mid-40s. This front will be moisture-starved, so we’re not anticipating any precipitation.

Friday – temperatures will slide back into the upper 30s and low 40s after the cold front.

Warmup this Weekend

We finally snap this bitter cold spell with an influx of warm air from the Gulf streaming ahead of a storm system that will move in next Monday. This weekend should feature gradually warming temperatures, and by next Monday we could hit 60 briefly.

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NYC Weekend Weather – Nov 14, 2014

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You can feel the chill in the air now. This cold will continue Saturday, but we’ll get a slight warmup Sunday and Monday ahead of a low pressure system moving in from the southwest. Behind that low pressure system, we get a reinforcing blast of arctic air that will be entrenched through the rest of next week. I’m also monitoring the potential for a Nor’easter just in time for the busy travel day Wednesday and through Thanksgiving.

Saturday – a cold day on tap despite ample sunshine. High temperatures will be generally in the lower 40s. There’ll be a noticeable northwest wind making it feel like it’s in the 30s.

Sunday – a milder day with warm air flowing in ahead of a low pressure system, but by warm, I mean highs only around 50. Clouds will increase throughout the day and there could be some rain Sunday night.

Monday – rain will be falling for the majority of the day, with highs in the city in the mid-40s. Monday night gets interesting with the potential for a rain/snow mix in the city, and all snow in interior regions north and west. Depending on the timing of the main slug of precipitation with this system, we could actually get some accumulating snow in the city also (the later in the night the main body of precipitation falls, the colder it will be, and the better the conditions for snow).gfs_namer_075_1000_850_thickTuesday – cold air rushes back in behind this storm on Monday and we drop back into high temperatures hovering in the low 40s.

Potential Thanksgiving Nor’easter?

In looking ahead at the long-term GFS model output, I’m noting the possibility for a possible high-impact Nor’easter that would be timed to coincide with the busiest travel day right before and then during Thanksgiving. Of course, this far out, there’s still considerable uncertainty to the forecast, so this scenario could not pan out, or the storm track could be nowhere close to where it needs to be to produce a high-impact Nor’easter. Still, it’s worth watching, as it could be a major headache for folks if it does materialize.gfs_namer_276_1000_850_thick (1)

NYC Weather Update – Nov 4, 2014

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Election Day features temperatures much above normal for this time of year, with high temperatures in the mid-60s under mostly sunny skies. Wednesday continues the warm trend but with increasing clouds. We’ll see another stormy end to the week before conditions improve this weekend.

Tuesday – the remainder of the day will feature high temperatures in the mid-60s reminiscent of early October and not November. This is all thanks to a warm front that passed through (you can see this in the diagram below for Wednesday, up and to the right of NYC demarcated by the red line). Go out and enjoy this while you can, and don’t forget to vote!

Wednesday – we’ll see an even warmer day despite the increase in cloud cover ahead of an approaching cold front. Southwesterly flow will allow warm, tropical air to surge into the area from the Gulf. This plume of warmth and moisture will also prime the atmosphere ahead of Thursday’s storm. The cold front itself will weaken as it passes, so we’re not anticipating any rainfall. High temperatures will be generally in the upper 60s.noaad2

Thursday – a storm system with its origins in the Great Lakes/Ohio Valley area will form a secondary low near the offshore waters of the Northeast. Despite being only 2 days out, there’s still some uncertainty to the ultimate track of this storm system. The general pattern will be somewhat similar to last week, with the coastal storm forming and then slowly making its way northeast. The availability of deep moisture suggests the possibility of bouts of heavy rain during the day Thursday into Thursday night. When all is said and done, we could be looking at rainfall totals in the 1.5″-2″ range across the area, depending on the final track of the storm. The further west the track, the further west the highest impact areas will be, and the inverse for tracks further east. High temperatures will remain mild until after the storm departs to the northeast, with high temperatures in the low 60s.

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GFS model output for Thursday

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Friday – rain should end early Friday as the low lifts to the northeast. Winds will pick up and shift towards the north, resulting in much cooler high temperatures only in the mid-50s.

We get a  cool but sunny Saturday before another chance of rain Sunday.

 

NYC Weekend Weather – Oct 24, 2014

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We are still feeling the impacts of that Nor’easter that passed through Wednesday and Thursday. There will be some lingering showers east of NYC this morning, before gradual things begin to dry out and skies gradually clear from west to east. High temperatures will be in the mid-60s, but with a north wind blowing, it will still feel quite cool. We’ve got an excellent, fall weekend on tap.

Saturday – we’ll get sunny skies again, and high temperatures will remain in the mid-60s.

Sunday – much the same as Saturday.

Monday – high pressure will continue to build to our south. This will mean a shift in winds to the south and southwest, which will open the door for warmer air to stream in from the south. High temperatures in the mid-upper 60s, under sunny skies.

gfs_namer_093_1000_850_thickTuesday – as that high pressure strengthens, we’ll get another day of even warmer temperatures Tuesday with highs near 70. We’ll be watching for another storm system approaching from the west that could bring us a chance of rain Wednesday.

NYC Weather Update – Oct 14, 2014

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Apologies for the lapse in posts last week. There was plenty to talk about with the formation and dissipation of Hurricane Fay, and with Hurricane Gonzalo developing. Gonzalo won’t be a threat to the U.S. mainland, but may wreak havoc in the vicinity of Bermuda as a low end Category 3 storm with 115-120mph sustained winds. This storm has the potential to hit Category 4.

Back to our region:

Today – we get to enjoy a very warm day for this time of the year with highs in the mid-upper 70s and sunny skies! Unfortunately, clouds will begin spreading over the area in a few hours time ahead of a system described in detail below.

Wednesday – there will be a chance of light rain in the morning, with the chance for more substantial rainfall increasing in the afternoon. Temperatures will remain mild in the mid-70s with persistent southeasterly flow channeling in warm, moist air from the south ahead of the cold front and storm system that was responsible for a severe weather outbreak in parts of the Midwest and Southeast earlier this week.

Thursday – will be the main event. Lucky for us, the storm system coming at us won’t be bringing severe weather, however, a thunderstorm or two is not out of the question. The main issue for us will be the risk of flooding from this slow moving system. Forecast models show training of storm cells, meaning the same areas will get hit repeatedly or continuously with moderate rain showers. Rain will likely be falling throughout the entirety of the day Thursday with little or no breaks. Rainfall totals of nearly 2″+ could lead to some minor flooding. However, the rain is welcome since we are nearly 3″ below average for rainfall. Temperatures should again remain on the warm side with highs in the mid-70s.

NAM high resolution model output for Thursday, Oct 16 @5PM
NAM high resolution model output for Thursday, Oct 16 @5PM – note the bright blue and purples stretched over the area, indicating bands of heavier rain
Precipitation total forecast for 8PM Wednesday-8PM Thursday. Nearly 2" for the NYC area.
Precipitation total forecast for 8PM Wednesday-8PM Thursday. Nearly 2″ for the NYC area.

Friday – things settle down quickly as a brief window of calm weather enters the picture. Temperatures will be cooler in the wake of the cold front with west winds and highs in the lower 70s.

NYC Weekend Weather – Oct 2, 2014

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Friday and Sunday will be the sunny and pleasant bookends to what will be a stormy and rainy Saturday this weekend.

Today – we’re looking at sunny skies and high temperatures in the low 70s. Clouds will begin to build back in later in the evening as the storm maker for Saturday begins to move in from the west.

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NAM high resolution model output for Saturday at 10AM EDT
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Weather Prediction Center forecast map for Saturday

Saturday – a negatively tilted frontal system will be moving over the area Saturday, with the worst of the rain coming between about 10AM-3PM. We will be in the vicinity of a triple point (junction between a cold, stationary, and occluded front, this feature is common with mature mid-latitude cyclonic systems) that will be draping south from a strengthening low pressure center that will be moving northeast into Ontario during this timeframe. A thunderstorm is not out of the question given the atmospheric dynamics. Temperatures should hover around the 70 degree mark despite the cloud cover and rain because of the potential for us to briefly enter a warm sector between the stationary front and cold front.

Sunday – we get a crisp blast of autumn air behind the frontal system passing through Saturday. Sunshine returns just in time for the annual BikeMS NYC, which yours truly will be participating in. Cool temperatures will be only in the mid-upper 60s.

Monday – good weather sticks around for the start of the work week with high temperatures around 70.

Our next chance for precipitation should come Tuesday-Wednesday. The low pressure center responsible for the rain Saturday is forecast to close off and retrograde (move west instead of east, with prevailing upper level winds) over central Canada. An impulse of energy will rotate around this center and lead to another cold front passing through our area.

 

NYC Weather Update – Sept 30, 2014

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The skies look gloomy today, but there’s not a high chance of precipitation as the best dynamics for showers remain mostly offshore and to the east. High temperatures will be a bit above average with high temperatures in the low 70s.

Wednesday the chance for scattered showers will remain with a stationary frontal boundary slow to push south through our region. The best chance for precipitation will again lie to the east, likely well away from the city. High temperatures will be somewhat cooler around 70 with mostly cloudy skies.

Thursday – following the passage of the frontal boundary above, high pressure will build in from the north. Cloud cover should decrease gradually though not entirely clearing, but northeast and easterly wind will lead to cooler temperatures with highs only nudging the 70 degree mark.

Friday should be much the same as Thursday, with high temperatures right around 70 and clouds & sun.

GFS model output for Saturday, Oct 4, 2014
GFS model output for Saturday, Oct 4, 2014

Saturday – the forecast models are unambiguous in anticipating the passage of a negatively tilted cold front through the region (negative tilt in the northern hemisphere would correspond to a frontal boundary where the northern end lies to the west of southern end of the boundary, these types of fronts are often associated with higher levels of instability). Temperatures will be cool in the upper 60s to around 70, with a period of steady showers likely at some point during the day, right now it’s looking like this will be during the morning hours.

NYC Weekend Weather – Sept 12, 2014

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Although the passage of a cold front yesterday didn’t bring any precipitation with it, you can definitely feel its impact in the form of much cooler and drier air today. Temperatures will be in the low 70s today with crisp, clear skies above.

Saturday – cloud cover will build tonight as an area of low pressure originating from the Tennessee Valley area slides along the frontal boundary that’s now located offshore to our east. This low pressure system will bring a solid chance at rain tomorrow especially later in the day into the evening hours. High temperatures will be cool, around 70, under cloudy skies.

NAM high resolution model output for Saturday evening at 8PM
NAM high resolution model output for Saturday evening at 8PM

Sunday – luckily, this storm system will exit rather quickly to our east, making Sunday an excellent day for outdoor activity of all varieties. Temperatures will be on the cool side, with highs in the low 70s under partly cloudy skies.

Monday – this week begins a trend towards cooler, fall-like temperatures as an upper air pattern favoring the intrusion of a cool, Canadian airmass takes hold. Highs on Monday will again only be in the low-70s, about 5 degrees cooler than average for this time of the year.

Tuesday – brings us our next shot at rain, as a weak impulse of energy passes through. The rest of the week after Tuesday looks like it will be uneventful, albeit on the cool side with the aforementioned arrival of a Canadian airmass and high pressure.

GFS 500mb vorticity and height model output. Note the two areas of very strong vorticity and closed heights in the Atlantic and Eastern Pacific corresponding to two tropical systems.
GFS 500mb vorticity and height model output. Note the two areas of very strong vorticity and closed heights in the Atlantic and Eastern Pacific corresponding to two tropical systems.

NYC Weekend Weather Update – Sept 4, 2014

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We’re still in the grips of a warm and humid airmass, despite some cooling off last night due to the passage of a weak cold front. This warm trend will not break until a stronger cold front passes through the region on Saturday.

Friday – expect high temperatures once again in the mid-upper 80s, albeit with increasing cloud cover as stratus cloud decks start to filter in ahead of the aforementioned cold front.

GFS model output for 2PM EDT Saturday
GFS model output for 2PM EDT Saturday

Saturday – unfortunately, the timing of the cold front above does mean it will bring adverse impacts to our weekend plans. Showers and thunderstorms are likely to precede and accompany this frontal passage, particularly later in the day Saturday into Saturday evening. High temperatures ahead of the front will remain warm in the mid-80s, somewhat cooler near the shore. There will be a noticeable cooling with this round of storms.

Sunday – Clouds will diminish through the course of the day Sunday as a much cooler regime works its way into the area. High temperatures will only be in the upper 70s for Sunday and the beginning of the weak.

Monday – Skies will be mostly clear, and temperatures will be much cooler in comparison to Labor Day, with highs only in the upper 70s (~10 degrees cooler than Labor Day). High pressure building over us will lead to an onshore wind flow, bringing in a cool, maritime polar airmass.

Cool onshore flow due to high pressure Monday
Cool onshore flow due to high pressure Monday

 

NYC Weather Update – Jul 21, 2014

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This will be my last weather update for the next 3 weeks as I will be traveling to Costa Rica during that time.

Tuesday – things will heat up on Tuesday as the high pressure center responsible for the what has been a refreshingly cool and fair stretch of weather moves to the southeast. This will allow warm, tropical air to move back into the area, setting the stage for high temperatures to climb well into the mid-upper 80s under partly cloudy skies.

Wednesday – the hot weather will intensify Wednesday as temperatures near or top 90 with a noticeable increase in humidity as well. Warm, humid air will be sandwiched between the Bermuda high and an approaching cold front. Scattered showers and thunderstorms are possible later in the day Wednesday. Inland areas to the west of NYC are most likely to see precipitation Wednesday.

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Thursday – the aforementioned cold front will move further east, giving the city itself its best chance of a soaking rain on Thursday. Given the humidity and amount of water available for storms Thursday, flash flooding is possible within the heaviest downpours, otherwise mostly cloudy with temperatures in the mid 80s. I wouldn’t be surprised if a few strong to severe thunderstorms popped up Thursday.

Friday – the cold front will clear our area and exit to the east, while cooler air filters down from Canada. High temperatures will return to the low 80s with mostly clear skies.

The Weekend – looks like the weekend itself will be another nice one, with high temperatures in the low 80s both Saturday and Sunday. There is a chance of showers and thunderstorms Sunday leading into what appears to be a fairly active weather pattern for the beginning of next week.