Category Archives: Flooding

NYC Weather Update – Apr 16, 2018

This work week starts off with a serious soaking rain from a storm system that has impacted a wide swath of the southern US with multiple days of severe weather. Conditions improve tomorrow and Wednesday before another chance for rain on Thursday. The rain this morning has led to the issuance of flash flood warnings, and numerous reports of flooding have already come in, so take caution out there, especially if you’re out on the roads.

Rest of today – rain, heavy at times, with the threat for flash flooding and flooding possible as storms train and hit the same areas repeatedly. Some embedded thunderstorms have been occurring this morning, enhancing the heavy rainfall potential. Some areas could see rainfall rates of up to 1″/hr along with gusty winds in the 40-50 mph range. Temperatures will be rising into the upper-50s as a warm front approaches from the south.

Tuesday – improving conditions as the storm system responsible for today’s rain moves off. Cooler, with temperatures maxing out in the low-50s in the wake of a cold front and mostly cloudy skies.

Wednesday – the best day of this week with high temperatures in the mid-50s and mostly sunny skies.

Thursday – another storm system, albeit weaker, will impact the area. High temperatures should hover in the mid-50s with chances for rain and cloudy skies otherwise.

 

NYC Weekend Weather – Mar 2, 2018

March arrives as a roaring lion this year with a powerful nor’easter impacting the region during the first half of the weekend. A variety of hazards from snow to high winds to coastal flooding will affect the area before this nor’easter meanders its way out to the open ocean. Behind this storm, the large scale pattern shifts and much cooler air rushes in, displacing unseasonable warmth with more average temperatures for the week to come.

Rest of today – rain and snow mixing. Little to no accumulation expected. Winds increasing from north to northeast winds 20-25 mph to 30-35 mph with gusts as high as 60 mph near the coast possible later today. Moderate coastal flooding possible over multiple tide cycles tonight, and Saturday. These tides will be higher than normal since they are falling on the full moon (spring tides). Temperatures will hold steady in the upper-30s.

Overnight, an inland low and coastal low consolidated offshore of the Northeast and the coastal low has already rapidly strengthened to a minimum pressure of 984 mb this morning. Two branches of the polar jet have phased together, providing the energy for this robust storm. As the storm continues to deepen, the pressure gradient between it and an area of high pressure over the Upper Midwest will continue to increase, leading to stronger winds. Onshore flow of these winds from the north and northeast over an extended period of time are expected to bring coastal flooding. Periods of moderate to heavy rain could lead to flooding in general. Although the cold, northwest flank of the storm as it exits to the east will support snow (with its cold conveyor belt), accumulations at the coast should be limited. This is another story inland where heavy snow is expected in the Lower Hudson Valley.

Saturday – periods of moderate to heavy rain with snow mixing in continue overnight, but should taper off by the morning. Winds will diminish from the 30 mph range with gusts up to 55 mph overnight but will remain stiff in the 20-25 mph range from the north. Much colder feel with highs in the mid-40s under partly sunny skies.

Sunday – much nicer day, winds finally abating with high temperatures in the mid-40s and mostly sunny skies.

Monday – sunny, with high temperatures in the mid-40s.

NYC Weather Update – Apr 3, 2017

wwwThe first week of April kicks off with multiple rounds of rain. Two separate storms are expected to bring drenching rains on Tuesday and Thursday. There may be some minor flooding concerns with 1″ of rain possibleĀ out of each system, on top of the rains we received last week.

Rest of today – cloudy, mild, with high temperatures in the upper-50s. Not a bad day for the Mets season opener.

Tuesday – late Monday, rain starts moving in ahead of an advancing warm front. Rain should begin around 10PM this evening and pick up in intensity overnight. Some thunderstorms are possible. Rain continues through most of the work day Tuesday, with some heavy rain possible. Mild again with high temperatures in the upper-50s.

Wednesday – brief respite between two storm systems, a gem of a spring day with high temperatures in the low-60s and mostly sunny to clear skies.

Thursday – temperatures cool off into the low-50s as the second storm system of the week impacts us and brings us yet another round of moderate to heavy rains.

 

NYC Weather Update – Jan 23, 2017

Main weather headline to start the week will be a potent and slow-moving coastal storm bringing a variety of hazards to the region later today through tomorrow morning. This storm is the same one responsible for this weekend’s deadly tornado outbreak down south. Conditions improve dramatically towards mid-week.

Rest of today – a flood watch, coastal flood advisories, and high wind warning are in effect mostly through tomorrow morning. Cloudy with high temperatures steady around 40Ā°F. Winds continue to increase throughout the day as a strengthening coastal low approaches and the pressure gradient between it and a high pressure center over Quebec tightens. A low-level jet will enhance winds. Sustained east and northeast winds of 30-40mph with gusts between 50-60mph will become commonplace late today and overnight. The strongest winds will occur closest to the coast.

Along with the strong winds, periods of heavy rain will bring the potential for 1-3″ of precipitation, which could lead to minor to moderate urban and small stream flooding. Timing of the onset of rain will be around 3pm this afternoon.

The persistent and strong northeast winds off the water will contribute to minor to moderate coastal flooding. This will be exacerbated during a couple of high tide cycles.

High resolution rapid refresh model simulated radar output for 3PM this afternoon
The storm approaching spans the better portion of the entire East Coast

Tuesday – rain and wind abate during the day, tapering off by the afternoon. High temperatures about the same as today in the low-40s.

Wednesday – as the coastal storm continues to pull away, temperatures rebound and mostly sunny skies return. High temperatures anticipated around 50ĀŗF.

Thursday – another nice day with high temperatures in the upper-40s and mostly sunny skies.

 

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

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 80ĀŗF.

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Post-tropical cyclone Hermine this afternoon

Labor Day (Monday)Ā – 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

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 80ĀŗF.

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.

 

NYC Weekend Weather – Aug 11, 2016

The second half of this week and this weekend will feel as though we’re living in a tropical monsoon climate zone, given the extended period of unsettled weather that we’ll be experiencing. Nearly every day over the course of the next 5-7 days, we’ll see a chance for showers and thunderstorms, some capable of producing torrential rainfall, along with a very warm and humid airmass staying in place.

Rest of today – periods of clouds and sun, likely becoming mostly cloudy this afternoon. There will be a chance for showers and thunderstorms, with the first batch appearing to arrive around lunch. High temperatures will be around 90ĀŗF but with the very humid air, heat indexes will be well into the upper-90s. This is the reason for there being a Heat Advisory in place until Saturday evening.

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Friday – similar set up to today, periods of sun mixed in with mostly cloudy spans as well. Highs will again be around 90ĀŗF, with a chance for showers and thunderstorms in the afternoon hours. The exact timing, placement, and intensity of the storms for Friday and this entire forecast period will be difficult to forecast with accuracy ahead of time.

This is due to the fact that many of the storms will be driven by subtle perturbations in the atmosphere moving around the periphery of a Bermuda High, and differential day time heating – hence why the chance for showers and thunderstorms is greatest in the afternoon hours. Sea breeze convergence boundaries are likely to serve as triggers for these storms. This Bermuda High is what has been and will be responsible for maintaining the oppressively hot and humid conditions. The tropical airmass it brings will mean that any storms that form will have the potential to tap into tropical moisture and produce very heavy rain that could lead to localized flash flooding.

Saturday – will be by far the hottest day of the weekend with high temperatures forecast to reach into the mid-upper 90s. Heat indexes will be in the upper-90s to low-100s in some parts, likely triggering Excessive Heat Warnings. Once again, a chance for showers and thunderstorms will occur in the afternoon hours.

Sunday – a cold front will approach the region on Sunday, which will lead to a more consistent and higher chance for organized thunderstorm activity. High temperatures will remainĀ hot, in the low-90s.

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Monday – low confidence for the forecast through Monday, as the timing of the cold front passage is uncertain. It may linger, which would result in yet more chances for rain. High temperatures should cool off to below 90ĀŗF in the upper-80s.

NYC Weekend Weather – Jul 28, 2016

We finally get a break from the heat along with some much needed rain in theĀ next few days. Saturday looks to be the best day of the weekend. High temperatures this weekend will range anywhere between 15-20ĀŗF cooler than last weekend.Ā 

Overnight – lows in the mid-70s as a low pressure center passes almost directlyĀ over NYC. Because the low will be right over us, the main area of the heaviest rain will remain north of the city.

Friday – showers punctuated by periods of steady, heavier rain as bands of rain develop and wrap around the low pressure center as it tracks east. HighĀ temperatures inĀ the low-80s with overcast skies. This low pressure system will thrive off the humid, tropical airmass in place over the region. A flash flood watch has been issued to reflect the possibility of some areas receiving 1-2″/hour rains. Embedded thunderstorms are possible, but are unlikely to reach severe limits. The bulk of the rain will fall overnight into the morning hours, and should begin tapering off in the afternoon from west to east.Ā 

Screen Shot 2016-07-28 at 6.53.30 PM fill_94qwbgSaturday – high pressureĀ passesĀ briefly giving us a mostly dry day with partly sunny skiesĀ with highs in the mid-80s.

Sunday – another disturbance pushesĀ through from the southĀ providing more chances for rain and thunderstorms.Ā Mostly cloudy with highs in the low-80s otherwise.

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Monday – skies graduallyĀ clear and temperatures warm back into the low-mid 80s.

Tuesday – warm and sunny with highs again in the mid-80s

Drought Conditions Forecast to Persist

Despite the rains this weekend, many parts of the area remain under aĀ moderate drought, having received only about 25% of normal precipitation for this past month. The outlook for the season calls for persistence of droughtĀ conditions as below normal to normal precipitation will be insufficient to break the drought.

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NYC Weekend Weather – Jul 7, 2016

The end of this week will likely see the first official heat wave of the year, typically defined as 3 or more days with 90ĀŗF+ temperatures. The hot and humid weather comes to a close this weekend as a backdoor cold front brings relief by Sunday. A couple rounds of active weather could crop up this afternoon and again Friday night.

Rest of today – hot, humid, with a high in the low-90s. Periods of clouds and sun with increasing clouds this afternoon. The area is under a flash flood watch due to the impending onset of showers and thunderstorms capable of generating heavy downpours of 1-2″/hour. You can see from the satellite image below that discrete, pulse type storms are already building. Coverage of these storms will increase and they will encounter conditions conducive for strengthening, with plenty of moisture in the atmosphere, no capping to speak of, and lots of sunshine leading to MLCAPE values between 1000-1500 J/Kg. Storms should die down by later this evening. If you’re out and about, carry an umbrella because you may get dumped on.

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Friday – any relief from the heat from the storms today will unfortunately be short-lived. Temperatures Friday are expected to rise into the low-90s once again under mostly sunny skies. Friday night, as a backdoor cold front the northeast (so-called because it moves from northeast to southwest, the opposite of most cold fronts in the mid-latitudes of the Northern Hemisphere), we could see another round of showers and thunderstorms capable of producing heavy rain across the area.

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Saturday – with the backdoor cold front slowly progressing through the area during the day, some potential exists for scattered thunderstorms. Temperatures will be more comfortable in the mid-80s with mostly sunny skies otherwise.

Sunday – mostly sunny with a high in the mid-80s. Best day of the weekend!

NYC Weather Update – Hurricane Joaquin in the Picture? – Oct 1, 2015

This week of damp, grey weather is leading up to a weekend when the uncertain future of Hurricane Joaquin may have an enormous impact on our weather. Since its formation earlier this week, Hurricane Joaquin has intensified steadily into a Category 3 storm currently spinning around the Bahamas. Joaquin’s future is still highly uncertain, and there’s been considerable spread between major forecast models as to where the storm will be at the end of the weekend. At this point, a landfall in the NYC region late this weekend is not out of the question.

Rest of today – cloudy and cool with high temperatures only in the mid-60s.

Friday – rain at times, windy and raw, with northeast winds in the 20-25mph range. It will feel like November with highs only in the mid-50s.

Saturday – similar to Friday in terms of sensible weather, with highs only in the upper-50s.

Sunday – this is where things get interesting depending on the track of Hurricane Joaquin. Depending on how closely Joaquin comes to hitting us, we could be looking at tropical storm conditions building through the day. If, on the other hand, it recurves out to sea, Sunday could be the best day of the weekend.

The Big Question: Where’s Joaquin Going?

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Currently, Joaquin is a Category 3 storm over the Bahamas, with noticeable central eye, and symmetrical outflow in satellite images. Joaquin has been moving southwest along the edge of a subtropical ridge. Joaquin is an environment favorable for continued intensification, sitting over some very warm water with moderate wind shear.

Forecast Track

Over the last couple of days, forecast models have been set in basically two camps, one curving Joaquin northwest into North Carolina or Virginia. The other camp continues to point to a recurvature of Joaquin. Given the large spread between the models, National Hurricane Center forecasters have been emphatic about the degree of uncertainty with the track forecast up to this point.

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Some major forecast models’ track forecasts for Joaquin
Official NHC track forecast
Official NHC track forecast

Potential Impacts

Regardless of the landfall point for Joaquin, it will be contributing to a plume of tropical moisture leading to widespread heavy rainfall over a large portion of the east coast.

With the persistent northeast winds ahead of the northward advancing Joaquin, coastal flooding is also likely to take place in flood prone areas.

5 day rainfall totals
5 day rainfall totals