Monthly Archives: September 2016

NYC Weekend Weather: TS Matthew – Sep 29, 2016

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We are in an active weather pattern for the entirety of the weekend, with chances for rain nearly every day. This rain is welcome and much needed, as drought persists across much of the area. Friday looks to deliver the heaviest, most persistent rain. We’re also closely monitoring the progress of Tropical Storm Matthew. While Matthew is still only in the Caribbean, it appears increasingly likely it will impact the East Coast next weekend.

Today – high pressure anchored over southern Quebec/southeastern Canada will serve to block the progress of an upper-level low that’s been drenching areas of the Mid-Atlantic. The influence of the high should keep most of the region relatively dry today, with the exception of further west in New Jersey. However, the high pressure to the east and frontal boundary siting just south of us will induce an onshore northeasterly wind, bringing cooler than normal temperatures only in the mid-60s.

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Friday – rain chances ramp up considerably Friday as the front depicted to the south edges slightly northwards. This looks to bring a batch of moderate to heavy rain onshore primarily in the afternoon and evening hours. Temperatures will be even cooler than today in the low-60s with overcast skies and that persistent northeast wind.

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Saturday – temperatures warm up a little into the upper-60s, but rain chances continue throughout the day along with overcast conditions.

Sunday – rain chances begin to diminish as temperatures continue to warm to around 70ºF. Even if rain doesn’t fall, it’ll still be a cloudy day.

Tropical Storm Matthew – Potential East Coast Impact?

Tropical Storm Matthew formed just east of the Lesser Antilles a couple days ago as a vigorous tropical storm and has been steadily progressing west and growing in intensity. Matthew is already a 65mph storm. It is being impacted by moderate southwesterly wind shear that will impede significant strengthening the next couple days. However, this shear is expected to ease as it moves over the warmest waters of the Caribbean. That should allow for more rapid intensification.

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Of course, Matthew is far from being a threat to us now, but for days, it’s been clear from various forecast models that this storm will eventually turn north. The pivotal question for whether Matthew becomes a direct threat to us is when this turn north occurs. It’s not looking particularly good for us now, as the forecast package from the National Hurricane Center continues to suggest Matthew will eventually move up the East Coast next week.

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NYC Weather Update – Sep 26, 2016

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Fall has arrived. Temperatures have cooled noticeably, even though technically, they are still in the above normal range. There will be a few chances for much needed rain during the week, overnight into Tuesday, then during an extended period in the second half of the week.

Rest of today – increasing clouds with high temperatures hovering in the low-70s.

Tuesday – overnight into Tuesday, we’re expecting a fairly robust cold front to push through with enough moisture to give some areas around 1″ of rain. This is some much needed precipitation as we’re far behind where we should be for this time of year and a moderate to severe drought continues to grip much of the area. Rain should taper off for the most part by the AM rush Tuesday, with some lingering showers possible. Ahead of the cold front actually passing through, wind flow turns to the south, allowing temperatures to rise into the upper-70s.

Wednesday – the cold front passing through Tuesday will be the spawn of a low pressure center that will stay relatively stationary over the upper Great Lakes, but by later Wednesday, this low pressure will begin to transfer energy to a new low that will form closer to the coast off of Virginia. This low will eventually lead to steady rain chances for the remainder of the week, starting with a small chance on Wednesday. High temperatures are expected to be in the mid-70s.

Thursday – this begins a stretch of unsettled weather as the low mentioned above meanders, and retrogrades (moves west) and inland from the coast. This low will become cutoff from any meaningful steering currents, which means it’ll stick around for a few days. High temperatures will be cooler Thursday around 70ºF with mostly cloudy skies and periods of rain.

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Drought Not Likely to Dissipate

Below normal precipitation continues to be expected for the region, which is still gripped by moderate to severe drought, in particular on eastern Long Island.

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NYC Weekend Weather – Sept 22, 2016

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Today marks the official start of astronomical autumn, even though it will feel anything but fall-like today. Temperatures cool off considerably this weekend, which will lead us into a period of average to below average temperatures for the next week or so.

Rest of today – warm with high temperatures in the low-mid 80s and sunny skies.

Friday – warmer still with high temperatures in the mid-upper 80s and mostly sunny skies. Small chance for showers overnight as a cold front encroaches from the west.

Saturday – with the aforementioned cold front swinging through, we will get a noticeable change in airmasses from a more humid, tropical influence we’ve felt the last few days, to a drier, cooler, continental airmass from Canada. The resulting swing in temperatures will be dramatic, with high temperatures on Saturday ranging 10ºF lower than Friday in the mid-70s.

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Sunday – one of many sunny, fall-like days coming with temperatures in the low-mid 70s.

Monday – almost a clone of Sunday, sunny with highs in the low-70s.

NYC Weekend Weather – Sep 16, 2016

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Yesterday was the Mid-Autumn Festival, a traditional harvest festival celebrated by many cultures in East Asia. It certainly felt more fall-like yesterday with below average temperatures after we spent one day near 90ºF on Wednesday. The fall weather continues this weekend, with a chance for some much needed rain Sunday.

Rest of today – crisp and cool with high temperatures below normal in the low-mid 70s.

Saturday – a bit warmer, with temperatures a couple degrees above normal under sunny skies, in the upper-70s.

Sunday – ahead of an advancing cold front, we could see showers, thunderstorms, and heavy rain, particularly in the afternoon. high temperatures will warm up a little ahead of this front, into the low-80s under mostly cloudy skies.

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Monday – since the frontal boundary won’t pass through until late in the day, there’s a lingering chance for showers with high temperatures hovering around 80ºF.

 

 

NYC Weather Update – Sep 12, 2016

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After a steamy end of the week last week, we get a refreshing change to fall-like weather for most of this week. The only exception will be Wednesday, when there looks to be a return to hotter temperatures.

Rest of today – high pressure is in control for today, which should yield mostly sunny conditions with high temperatures in the mid-upper 70s.

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Tuesday – high pressure moves a bit further to our east, allowing for warmer air to flow in from the south. This will result in temperatures warming up to around 80ºF with sunny skies.

Wednesday – as the high pressure center above continues to move east, return flow form the south and southwest will continue to warm temperatures up and increase the humidity. High temperatures are expected to be in the mid-upper 80s.

Thursday – a weak cold front will pass through overnight Wednesday into Thursday. In the wake of this frontal boundary, a new area of high pressure will build over the Great Lakes. This will result in much cooler temperatures, in the mid-70s with a northerly wind. Thursday night, which is the Mid-Autumn Festival, should see spotless skies for moon viewing.

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NYC Weekend Weather – Sep 8, 2016

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This past week, weather headlines were dominated by the uncertain course of how Post-tropical Cyclone Hermine would unfold. Now that Hermine has dissipated and is well behind us, we look ahead to the end of the week which will start off warm, but cool off somewhat.

Rest of today – it’s sunny now, but clouds are moving in from the north and west, and will likely result in partly sunny skies later on. High temperatures will range into the upper-80s and around 90ºF in some parts.

Friday – with an area of high pressure to our southwest, warm, humid air from south will flow into the region allowing temperatures to rise into the low-90s. There is a chance for isolated thunderstorms during the afternoon.

Saturday – a frontal boundary will be lingering in our vicinity during the day. This should yield a mostly cloudy day with a chance for scattered showers and thunderstorms throughout. High temperatures will be a bit cooler, in the mid-upper 80s.

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Sunday – the frontal boundary pushes through as a cold front and brings in some relief from heat and humidity. Skies will clear and allow temperatures to rise to the mid-80s.

Drought Persists, Some Relief Ahead?

Parts of our state are still dealing with an extreme drought, though in our region, we’re “lucky” enough to only have a moderate to severe drought in parts of Long Island. The monthly outlook does call for some drought relief for Long Island, though.

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NYC Weather Update – Post-Tropical Storm Hermine – Sep 4, 2016

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Although tropical storm warnings are still up for the five boroughs, coastal Connecticut, Long Island, and New Jersey, it appears at this time that the threat from Hermine is diminishing. The center of Hermine is now located well out into the Atlantic Ocean, and even if it does make its eventual turn to the north and northwest, it will be far enough east of us that most impacts should be on the moderate side.

Rest of today – over the last few days, Hermine has continuously trended east of the official National Hurricane Center forecast track, and has still not made a turn to the north or northwest. It is still forecast to make that turn today, bringing it closer to shore, and increasing clouds in the area. Winds should pick up as well, with high temperatures around 80ºF.

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Post-tropical cyclone Hermine this afternoon

Labor Day (Monday) – assuming that Hermine does make its projected turn towards the coast, Monday would entail a chance for rain, as well as strong winds, possibly approaching tropical storm force. High temperatures are only expected to reach into the upper-70s in this scenario. Could be a tough day for the Caribbean Day Parade.

Personally, I do not believe Hermine will produce tropical storm conditions (sustained wind greater than 39mph, less than 74mph). during this time, the confidence in this track forecast has been low, and any turn towards the coast has yet to verify. That said, nothing about this complex storm would be surprising, and a shift in storm track 50-60 miles west could dramatically increase the likelihood of the city receiving tropical storm conditions. Primary impacts will still be moderate to major coastal flooding with multiple tide cycles of storm surge and large waves leading to serious beach erosion in some places.

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Based on latest track forecasts and current position of Hermine, NYC rests in a zone of 30% chance of experiencing tropical storm force winds, with the probability increasing sharply further east.

Tuesday – could end up being a pretty decent day if Hermine is further off to the east at this point. If that happens, we’ll probably see decreasing clouds and improving conditions with high temperatures in the mid-upper 80s. If Hermine sticks around, then we could see another day of wind and rain.

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Will be posting another update tomorrow.

 

 

NYC Labor Day Weekend Weather – TS Hermine – Sep 2, 2016

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I wrote that I would not be posting any updates while on vacation unless there were to be a special event that warranted it. Well, the likely approach of the remnants of Tropical Storm Hermine into the offshore waters in our region certainly warrants this special update. As of now, it appears that Labor Day itself will be the only day when we could see significant impacts from this storm, but this could change. I will likely have another update Sunday.

Rest of today – sunny, and pleasant with a high in the low-80s. This will be by far the best day of the long weekend.

Saturday – increasing clouds, high temperature around 80ºF.

Sunday – mostly cloudy, with chances for rain increasing in the afternoon. Cool, with highs only in the mid-upper 70s.

Labor Day (Monday) – tropical storm conditions possible, strong and gusty winds, and possible periods of heavy rain, especially in coastal areas. Dangerous rip currents at the beaches, as well as moderate to major coastal flooding. Mostly cloudy otherwise with high temperatures in the upper-70s.

Tropical Storm Hermine this morning
Tropical Storm Hermine this morning

Tuesday – with the remnants of Hermine currently forecast to linger off of the coast of the Northeast, we could see another day of possible tropical storm conditions. Warmer, with high temperatures in the low-80s.

Tropical Storm Hermine’s Forecast

Since the inception of Hermine as a tropical wave off the coast of West Africa, forecasters have had difficulty in accurately capturing the track and intensity of this storm. Its approach towards our region is no different. The forecast is complicated by the fact that Hermine will be completing a process of extratropical transition. A complex set of interactions between it and a frontal boundary adds a high degree of uncertainty towards the late period of this forecast.

Forecast Track

As of this morning, the National Hurricane Center’s official 5 day forecast called for Hermine to continue tracking rapidly northeast just inland of the Southeast coast as it initially interacts with a frontal boundary in its vicinity. During this period, it is expected to weaken, but by Saturday evening, it is expected to re-emerge over open water off the North Carolina Coast. At this point, Hermine is expected to have completed extratropical transition. It will begin another interaction with a baroclinic frontal zone, which is expected to significantly slow its forward progress down. This slowing will likely also lead to the storm erratically meandering off the Northeast coast, possibly doing a loop.

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Some major forecast model’s current output for Hermine
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GFS ensemble models (spaghetti models), white denotes the consensus track

Intensity Forecast

During the period that the storm is over land, it will weaken continuously. However, by Saturday evening, when it is expected to re-emerge over open water, and complete extratropical transition, it will gain in strength. The extratropical transition will impart energy from baroclinic forces (interactions between airmasses of differing pressures), and the storm is expected to re-intensify into a strong extratropical storm with sustained winds of 60-65mph.

Impacts

The intensity and location of these impacts will depend greatly on the eventual track for this storm.

Tropical storm watches are in effect for the entire New Jersey coast. Heavy rain in coastal areas. Strong sustained winds, winds gusting in excess of 50mph in some coastal areas. Beach erosion along with coastal flooding, possibly for an extended period of time. High surf and dangerous rip currents.