Tag Archives: hurricanes

NYC Weather + Special Tropical Update – Sept 10, 2018

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This week kicks off with a prolonged period of unsettled weather as a warm front and a cold front both impact the area. Chances for rain will be with us through Wednesday. Conditions finally improve late in the week. We luckily will avoid direct impacts (aside from high surf) from what will be an extremely dangerous Hurricane Florence, which looks set to make landfall on North Carolina late this week. Aside from Florence, two other storms pose threats to US territories this week.

Rest of today – cloudy, with periods of rain, heavy at times, especially later in the day towards the overnight hours. High temperatures will be in the upper-60s with cool, persistent onshore flow from the east. Ahead of an approaching warm front.

Tuesday – chances for thunderstorms will persist into Tuesday, with this slow-moving warm front finally pushing through. There could be thunderstorms overnight. Then, later in the day, as the trailing cold front moves through. Once the warm front passes over, we’ll be within the warm sector of the parent low pressure system, which will allow temperatures to climb into the low-80s with a marked increase in humidity.

Wednesday – the cold front mentioned above will slow down as it approaches us and dissipate. This will lead to continuing chances for rain, and thunderstorms with temperatures again in the low-80s.

Thursday – high pressure will finally begin to build in to our north by Thursday behind the cold front above. This will lead to better conditions, with partly sunny skies and temperatures in the low-80s.

Friday – partly sunny skies with high temperatures in the low-80s again with high pressure to our north.

Florence, Isaac, and Olivia All Pose a Threat to the US

These three storms have the potential to impact the Southeastern US, Puerto Rico, and Hawaii respectively within the next week. Among these, Florence is by far the most dangerous, as it could make landfall on North Carolina as a Category 4 storm with maximum sustained winds of 145 mph.

Hurricane Florence

Over the past day or so, the picture for Florence has become much clearer. Various forecast models have come into remarkable alignment on both the overall track and intensity of Florence over the next 5 days, which means bad news for the Carolinas. The picture looks grim, with Florence set to make landfall as a very strong Category 4 storm packing sustained winds of 145 mph. Florence has nothing but warm water ahead of it, and there should be minimal impact ot this storm from vertical wind shear. Even if the storm weakens due to eyewall replacement cycles prior to landfall, that would only serve to increase the radius of its damaging winds. No matter how you slice it, Florence is likely to bring deadly storm surge and risk of life-threatening flash flooding and inland flooding. The fact that its forecast track slows to a crawl after landfall makes the flooding risk inland especially serious.

Hurricane Isaac

Isaac is a compact storm, which is leading to some uncertainty regarding both its track and intensity forecast. Small tropical cyclones are subject to wild swings in intensity both ways, which can be unpredictable at times. As of now, Isaac is forecast to cross the Windward Islands of the Lesser Antilles as a Category 1 storm, then continue into the Caribbean where hostile shear conditions should cause it to weaken. It is worth noting, despite the UKMET model being an outlier, that there are some signals that the storm could turn to the northwest later in the period, which could mean a threat to Hispaniola and Puerto Rico.

Hurricane Olivia

This storm continues to track towards Hawaii. Although weakening due to the influence of moderate wind shear, it is still set to hit Hawaii later this week as a strong tropical storm. The primary threat to Hawaii from Olivia will be in the form of heavy rain and flash flooding regardless of whether it makes direct landfall on one of the main islands.

NYC Weekend Weather – Sept 7, 2018

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Cooler temperatures are finally upon us after a very hot and humid week. However, the cooler weather also brings a prolonged period of cloudy conditions, with chances for showers each day this weekend. Rain chances continue into the beginning of next week with a storm system approaching. Long-term, we look towards the tropics, as Tropical Storm Florence continues to have the potential for bringing some impacts to the area.

Rest of today – overcast, with much cooler high temperatures in the mid-70s. Chances for showers, especially later in the day.

Saturday – cloudy with high temperatures remain cool in the low-mid 70s with northeasterly onshore flow behind a cold front draped west-east south of us. This front (which passed through yesterday) will become stationary. Multiple impulses of energy will run along this boundary and allow for continued slight chances of showers.

Sunday – yet another cool, cloudy day with chances for rain. High temperatures around 70°F.

Monday – the stationary front stalled out south of us will return north as a warm front. As this happens, chances for rain increase, along with temperatures rising back into the mid-upper 70s.

Will Tropical Storm Florence Impact the East Coast?

Tropical Storm Florence has been active over the eastern and central North Atlantic for over a week now. Within the last few days, Florence underwent a rapid intensification that brought it up to Category 3 status, making it the first major hurricane of the 2018 Atlantic hurricane season. Subsequently, it has weakened to a tropical storm under relentless strong shear. However, it is expected to reintensify into a major hurricane once shear subsides. Worrying trends in the track forecast for Florence continue to allow for the possibility of landfall on the East Coast, or at the very least, substantial coastal impacts like dangerous surf and beach erosion. However, the National Hurricane Center continues to note that there is considerable uncertainty to the track forecast for Florence, such that it is still too early to determine what effects it will have on the East Coast. This storm will warrant careful observation over the coming days and I will have subsequent updates on it.

NYC Labor Day Weekend Weather, Eyes on Irma – Sep 1, 2017

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It will definitely feel like the end of summer this weekend as temperatures will be much below average for this time of the year. The remnants of Harvey are also likely to put a damper on weekend activities Saturday night through a decent chunk of Sunday. Labor Day Monday itself looks like a gem. In the long term, I’m keeping tabs up Hurricane Irma, which worries me with its potential to affect the East Coast.

Rest of today – cool, with a Canadian high pressure center to our north-northwest, we’ll feel a refreshing north wind that will diminish through the day. High temperatures are only forecast to hit 70ºF or so even with sunny skies, 10ºF+ below normal for this time of year.

Saturday – temperatures remain cool in the uppper-60s with an easterly onshore flow ahead of an approaching warm front associated with the remnants of Harvey. Overrunning clouds will move in before rain chances build up overnight.

Sunday – rain lingers into the day on Sunday before ending by the afternoon. Mostly cloudy with temperatures in the mid-70s as we get some warmer return flow behind the storm with high pressure setting up to our southwest.

Monday – the warming pattering continues with highs returning to around normal in the low-80s with sunny skies. This is the best day for your holiday weekend grilling, and should be excellent viewing conditions for the annual West Indian Day Parade and carnival.

 

Hurricane Irma – possible threat to the East Coast?

We’ve entered the peak of the hurricane season and right on the toes of Harvey we have Hurricane Irma which put on an impressive display of strengthening the last couple days wen it went from a tropical storm to Category 3 major hurricane. It’s weakened a slight bit but conditions are still favorable for it re-strengthen into a powerful Category 3 of 4 storm before making an approach on the Lesser Antilles.

What is concerning to me is the storm is forecast to take a jog to the southwest over the weekend. The further south and west this storm gets before it starts the process of curving back out to sea at a higher latitude, the greater the chance that it could impact the East Coast of the US. There is still a lot of time so things could definitely change, but it is worth noting that current forecasts favor a more southerly track, enhancing the risk to us. I’ve seen GFS model runs show the storm make direct landfall on the Mid-Atlantic and Northeast. As of this morning, the GFS backed off of this type of scenario. It does bear watching though.

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 Weekend Weather – Aug 27, 2015

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We have a simply splendid weekend on tap. Temperatures will be on the upward trend through the end of this week and into the weekend. The warm trend will continue into the beginning of next week, along with a return of more humid, dog days of summer type weather. Keeping an eye on the tropics, a great deal of uncertainty surrounds the future of Tropical Storm Erika, which could effect the U.S. East Coast in the long term.

Rest of today – beautiful, sunny skies with high temperatures in the low-80s. High pressure to the west is firmly in control, delivering this pleasant, seasonable weather.

Friday – almost a carbon copy of today, high temperatures in the low-80s with even fewer clouds as the high pressure center will be parked right over us.

Saturday – as the high pressure from the end of the week moves offshore and weakens, a subtropical high pressure center begins to take to control. This setup favors a warmer, more humid regime. Winds will shift to the southwest and temperatures will begin to climb into the mid-upper 80s.

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Sunday – a longer term trend of warm and humid weather, typical of late summer, will continue Sunday. Temperatures will again be in the upper-80s. This trend looks to continue well into next week.

Tropical Storm Erika

A tropical wave that moved offshore of West Africa late last week has tracked across the Atlantic, strengthening along the way to become the fifth named storm of the 2015 Atlantic Hurricane season. Tropical Storm Erika, like its predecessor Danny, is having trouble maintaining its strength due to the influence of dry air and hostile northwesterly wind shear. Due to this shear, Erika’s center of circulation is actually still somewhat exposed (see below), and displaced away from its area of heaviest thunderstorms, which is concentrated in the southeastern quadrant of the storm.

The long term prospects for the storm are highly uncertain due to a number of factors. Erika looks to be tracking over Puerto Rico and may interact with Hispaniola (bringing much needed rain), which would significantly weaken the already feeble storm. This could lead to it dissipating entirely. However, should the storm make it past this area of high wind shear and possible land interaction, it’ll end up in the very warm waters around the Bahamas. This would provide the fuel for it to intensify quickly into a hurricane which could then threaten Florida and the East Coast. Definitely worth keeping an eye on.

Satellite image of Erika, with exposed center of circulation circled in red
Satellite image of Erika, with exposed center of circulation circled in red

NYC Weekend Weather & 2015 Hurricane Season Forecast – May 28, 2015

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Yesterday, portions of our area got some much needed rain from a round of thunderstorms associated with a prefrontal trough. Today, we get another shot at rain and thunderstorms as the primary cold front actually pushes through. Behind that front, things cool off and dry out for Friday, before the humidity returns on Saturday. Things should stay dry Saturday, but we will see a more substantial chance at widespread rainfall Sunday with the passage of another cold front. Also of note, the National Hurricane Center released its outlook for this year’s Atlantic hurricane season, calling for a below normal season.

Rest of today – clouds give way to sun with warm temperatures in the mid-80s. Showers and thunderstorms are expected to form later this afternoon. The atmospheric setup today is a bit more favorable to showers and thunderstorms being able to persist into NYC and western Long Island, unlike yesterday when these showers essentially died out as they hit the stable marine air layer near the coast. The exact location of where storms form and move into will still be tricky to pinpoint even at this time.

High Resolution Rapid Refresh model output simulated radar for 3PM EST today.
High Resolution Rapid Refresh model output simulated radar for 3PM EST today.

Friday – once the frontal boundary passes through later today, it will usher in a much cooler and drier airmass for Friday. Temperatures should top out in the mid-upper 70s (still 5-10ºF above normal) under sunny skies.

Saturday – temperatures will be slightly warmer in the low-80s on Saturday with an increase in humidity as well. There could be a slight chance for scattered thunderstorms later in the day as well.

Sunday – another cold front passes through the region Sunday, bringing with it the chance for more substantial and widespread showers. Temperatures will also cool off to around normal, in the low-mid 70s.

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2015 Atlantic Hurricane Season Outlook

The National Hurricane Center released its initial outlook for the 2015 Atlantic Hurricane Season that officially starts on June 1st. As you’ll see from the graphic below, forecasters are calling for a below normal season with 6-11 named storms (tropical storms with sustained winds greater than 39mph). Of these named storms, forecasters think 3-6 have a chance to intensify into hurricanes (maximum sustained winds greater than 74mph), and of those hurricanes 0-2 could become major hurricanes (Category 3 or higher, maximum sustained winds greater than 111mph). Outlook_2015_FINAL

 

The primary reason for the 70% probability of a below normal season is the disruptive effect of El Niño in the Eastern Pacific, which is known to alter the pressure and air currents over the tropical Atlantic, dampening the formation of hurricanes. On the other hand, the above average sea surface temperatures in the Pacific associated with El Niño are expected to induce an above average Pacific Hurricane/Typhoon season. Read the full statement from the NHC here: http://www.noaanews.noaa.gov/stories2015/20150527-noaa-hurricane-outlook-below-normal-atlantic-hurricane-season-is-likely-this-year.html

Hurricane Iselle – Tropical Update

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I haven’t been active on this blog the past couple of weeks as I’ve been in Costa Rica, however, the unfolding situation with Hurricane Iselle warrants a posting. I’ve observed Iselle as it formed from a tropical wave and then a tropical depression along the Inter-Tropical Convergence Zone off of the coast of Central America where I’m currently staying. Now, Iselle is closing in on the Hawaiian Islands and is set to make landfall on the Big Island this evening.

Despite the fact that the Hawaiian Islands lie near an active area for tropical cyclones, they are rarely impacted, in part due to the sheer vastness of open ocean versus the relatively small land area of the islands. During most years, a semi-permanent high pressure area that resides near the Islands also precludes the formation, strengthening, and penetration of cyclones into the region. This changes dramatically when El Nino conditions prevail, as they seem to be currently. Iselle will be the first landfalling hurricane to affect the Hawaiian Islands in 22 years since the devastating Hurricane Iniki of 1992. Fortunately, Iselle will be making landfall as a much weaker storm than Iniki, but regardless, it will still pack a serious punch.

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Satellite image of Hurricane Iselle with Hurricane Julio following behind. To the far left, you can see Hurricane Genevieve.

 

Track Forecast

With less than 24 hours before landfall, the forecast track for Iselle is essentially zeroed in. The official track forecast cone has Iselle hitting the Big Island straight on. The center of the current forecast track envelope, should it hold up, has Iselle potentially making a direct hit on the eastern portion of the Big Island, with the eye of the storm skirting just south or perhaps directly over the Hilo area. I would hope for a northward deviation of this track, as this would spare the region from the strongest quadrant of the storm’s winds and waves (in the northern hemisphere, the strongest quadrant of a cyclonic storm is generally the northeastern quadrant). In the case of Iselle, due to its forecast west-northwest motion, the strongest quadrant should actually be the northwest, since the forward speed of the storm is added to the winds in that area.

After making landfall on the Big Island, Iselle is forecast to move to the south of the rest of the islands, passing closest to Maui. Because of uncertainty in the track forecast, it is entirely possible that Iselle could end up making multiple landfalls on different islands. However, I would anticipate these subsequent landfalls to be less serious in nature as Iselle should weaken substantially due to the influence of interaction with the mountainous terrain of the Big Island as well as increasing vertical wind shear from the north and west. There could still be some damaging storm surge and high winds in the other Hawaiian Islands, especially if the center of Iselle passes to the south of them.

 

Intensity Forecast

Iselle has been stubbornly persistent in maintaining minimal Category 1 status. Forecast models have been giving conflicting signals as to whether Iselle will be impacted by increased wind shear. Forecasters had not anticipated that Iselle would enter into a col between two high pressure centers, essentially an area of very low wind shear, think of it as a calm spot between two swirling eddies. Different forecast models are providing two divergent scenarios: (1) that Iselle continues to move in tandem with the col, allowing it to maintain current strength, or (2) Iselle leaves the col and experiences much higher wind shear.

No matter what, Iselle will be making landfall on the Big Island as either a minimal Category 1 hurricane or a very strong tropical storm. The real impacts of either scenario will be hardly discernible. Wind over the Big Island should pick up substantially this afternoon and evening first from the northeast, then north, and then switching to the south and southeast overnight. Sustained tropical storm force winds in the range of 50-65mph are expected depending on the specific locale. Wind gusts of up to 90mph are also possible in some locations. Offshore waves will build from 6 feet to as high as 31 feet closer to the center of the eye. I hope all people on the islands are making adequate preparations. Wind speeds as high as the ones forecast could easily shred even a decently well constructed roof. I’m not sure if the local government has issued evacuation orders, but if so, I hope all citizens of Hawaii will heed the call and take every necessary precaution to secure life and property. Let’s hope this Iselle weakens some more before it makes landfall.

 

Notes

In contrast to the Atlantic Hurricane Season thus far, this year’s Pacific Hurricane Season has been quite active, in part due to the influence of anomalously warm sea surface temperatures over the Eastern Pacific. These temperatures are indicative of what could be the start of an El Nino event. Hurricane Iniki also formed during a very strong El Nino event.

Hurricane Arthur Update – Jul 4, 2014 @ 6PM EDT

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Hurricane Arthur is still being analyzed by National Hurricane Center as packing winds of 80mph. Although the inner core is still very symmetrical, you can see that the overall storm is beginning to lose some symmetry. In addition, central pressure has risen a couple millibar since earlier today, indicating the storm is continuing to weaken.

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There’s still plenty of rain in store for Southeastern New England, though, as a couple bands of heavy rain are still moving their way onshore. The worst of the storm is yet to come, with the center of Arthur forecast to make its closest pass to this portion of the country in the next couple hours. Overnight, tropical storm conditions are likely over portions of Eastern Cape Cod.

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Weekend Weather, Hurricane Arthur Update – Jul 4, 2014 @ 10AM EDT

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As of 9AM EDT, Hurricane Arthur has weakened somewhat from its peak intensity as a Category 2, and sustained winds have declined to 90mph. However, its eye is still clearly visible, and as you can see below, the storm is maintaining a symmetrical appearance with good outflow in all quadrants, meaning this is still quite a powerful storm. As Arthur continues moving northeast, it is expected to weaken rapidly upon entering much cooler waters and with increasing vertical shear from the codl front seen below.
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Track Forecast

Forecast models are in very close agreement about Arthur’s track over the next 12 hours or so. As you see below, they are tightly clustered around the 40N, 70W benchmark. Hence, forecast reasoning has not changed much since yesterday night. Arthur is expected to continue its northeast track and speed up under the influence of the cold front depicted above, moving offshore of New England and into the Canadian Maritimes as it makes extratropical transition.

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What This Means for Us

As expected, Arthur will be bringing multiple rounds of rain to the entire Northeast over the course of the day today. You can already see Arthur’s outer rain bands on our regional radar (you’d see it in the standard 124 nautical mile radar, but I’ve inserted an image of 248 nautical mile range radar image to see the storm better). As Arthur accelerates and makes its closest pass to this part of the country, we’ll see repeated bands of rain moving on shore. You can expect periods of heavy rain and thunderstorms, interspersed with some dry spells under cloudy skies.

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The Rest of the Weekend

Once Arthur and the cold front clear the Northeast, we will see a return to a spectacular weekend with high pressure building back in. Sunny skies, mild, and dry conditions will prevail across the entire region with high temperatures in the low-mid 80s on both Saturday and Sunday. As the high pressure moves to our southeast, we’ll see a return flow from the backside of the high pressure ushering in another warm, humid airmass for the beginning of next week.

 

Hurricane Arthur Update – Jul 3, 2014

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Hurricane Arthur has held steady with 90mph winds over the last 6 hours or so. The storm’s eye continues to grow more defined, with central pressure continuing to fall to 977mb. These signs point to further strengthening, and the National Hurricane Center is still forecasting Arthur to hit Category 2 strength as it makes its closest pass over North Carolina.

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Track Forecast

Over the course of the day, Arthur has moved further north than originally forecast, and is only slowly beginning to make its turn towards the northeast. As a result, most forecast models have been pushed a bit further to the west. Most of the models now have Arthur making landfall somewhere over coastal North Carolina, and then passing inside the 40N, 70W benchmark offshore of the Northeast. The bottom line is that the updated forecast track increases the likelihood of adverse impacts to coastal areas all along the East Coast. This includes high surf, beach erosion, and dangerous riptides even in areas that don’t see direct impacts. This new track also puts portions of Southeastern New England under risk of experiencing tropical storm conditions, and heavy rain bands from Arthur as it passes offshore.

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It’s a good thing that mandatory evacuations were placed for the Outer Banks and coastal North Carolina, as portions of these low-lying areas are forecast to experience storm surge inundation of greater than 3 feet during the peak of the storm.

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Blue shaded areas = 1-3′ of storm surge Yellow areas = between 3-6′ of storm surge