Category Archives: Outside of NYC

Hurricane Irma Update – 9AM Sep 9, 2017

Overnight, Irma made landfall on the Cuban Keys off the north shore of Cuba. Land interaction with Cuba has eroded Irma’s circulation to the point where it is now a marginal Category 4 storm containing 130 mph peak sustained winds. However, it would be unwise for anyone in Florida to dismiss this storm for reasons discussed below.

Current Situation

Irma has been downgraded to a marginal Category 4 storm with peak sustained winds at 130 mph. Despite only barely touching the Cuban coast, it’s clear from satellite imagery that land interaction has disrupted Irma’s circulation. The eye is no longer clearly visible. The western side of the storm looks ragged.

Headlines

  • Track forecasts continue to shift slightly westward from overnight. This lowers the risk for a direct hit by the eye of the storm in the Miami area. However, since the strongest winds in a hurricane in the northern hemisphere occur on the east side of the storm, Miami can still expect strong wind impacts.
  • Hurricane force winds extend 70 miles from the eye on each side. Tropical storm force winds are 400 miles in diameter with this massive storm.
  • The risk to the west coast of Florida continues to increase. Southwest Florida could see the worst storm surge with surge of 6-12′ forecast.
  • It is not out of the question that Tampa Bay could take a direct hit from the eye of this storm at Category 3 strength.
  • Irma could still re-intensify over the very warm waters of the Florida Straits once it moves away from Cuba.
  • Tornadoes in the bands of Irma as it moves north will pose a limited but dangerous threat.

Forecast Track

The high pressure over the central Atlantic that has steered Irma to this point continues to remain strong enough to keep it on west-northwest motion along the northern coast of Cuba. Based on this latest track forecast, it is possible that Tampa Bay takes a direct hit from Irma. Portions of the Florida Panhandle are also at increasing risk. This track also enhances the risk of inland impacts in Georgia and southeastern states.

Forecast Intensity

Irma has been weakened by interaction with the north coast of Cuba. It is now a marginal Category 4 storm with sustained winds of 130 mph. While some further weakening is possible, once Irma emerges over the very warm waters of the Florida Straits, weakening should cease. It could even re-intensify over these waters before making landfall. Keep in mind that Category 3 winds would still be very serious.

Uncertainties

  • Any further motion into Cuba would mean further degradation to the storm’s core and circulation which could result in more weakening.
  • There is a window for some possible re-strengthening over the Florida Straits.
  • An eyewall replacement cycle could still occur bringing fluctuations to the strength of the storm.
  • The exact timing of Irma’s turn north is still not certain. When it turns north will have large implications for who sees the worst direct wind impacts from the eye of the storm.

Hurricane Irma Update – 5PM Sep 8, 2017

This update is based on information from the National Hurricane Center’s 5PM advisory on Hurricane Irma.

Current Situation

Hurricane Irma continues to persist as a large and powerful Category 4 storm with peak sustained winds of 155 mph. Its eye still appears somewhat ragged, suggesting that it’s still undergoing an eyewall replacement cycle. This will continue to lead to fluctuations in its strength.

Headlines

  • Track forecast continues to edge westward. This decreases the risk Irma poses in any direct way to Georgia and South Carolina coastal areas, though storm surge threat here is still significant.
  • The threat of a direct hit on Miami is decreasing. However, a track to the west of Miami would result in the South Florida region being on the more dangerous eastern side of the storm.
  • The risk of devastating impacts to the west coast of Florida is increasing.
  • Irma’s eye may be moving very close to or make landfall on the northern Cuban coast. The threat of catastrophic wind and storm surge damage to Cuba’s north shore is increasing.
  • Risk of damage from flooding rains and tornadoes also exists. See this 1-5 day map of possible rainfall totals:

Forecast Track

Forecast models continue to edge slightly westward on a track for Irma and as such the National Hurricane Center has also adjusted its latest forecast slightly more west.

Forecast Intensity

National Hurricane Center forecasts continue to call for Irma to make landfall somewhere in South Florida as a very dangerous and powerful Category 4 storm. Outside of possible internal fluctuations and interaction with Cuba’s high terrain, there are no other inhibiting factors on Irma maintaining Category 4 strength of even possibly intensifying. Irma is entering an area of very warm sea surface temperatures with basically no mid-level wind shear.

 

NYC Weekend Weather – Hurricane Irma Update, Sep 8 2017

We’ve got a wonderful stretch of below average but sunny, fall-like weather ahead of us over the weekend. The main weather story lies far to our south as Florida braces for Hurricane Irma over this same time period. Irma has weakened a bit but is still a large and dangerous Category 4 storm capable of wreaking havoc over the entire state of Florida.

Rest of today – our weather will be dictated by an area of high pressure anchored over the Great Lakes. This will give us mostly sunny skies with a cool high in the mid-70s.

High pressure firmly in control of the weather in our part of the world. You can see Hurricane Irma making its finally approach on Florida in the lower right.

Saturday – sunny with temperatures in the low-70s as the high pressure over the Great Lakes moves east a bit.

Sunday – more of the same as Saturday with sunny skies and high temperatures in the low-70s.

Monday – slightly warmer with high temperatures creeping back into the mid-70s with some more clouds.

 

Hurricane Irma a Major Threat to South Florida

Current Situation

Hurricane Irma has been weakening in the last 12 hours. It’s evident the storm is undergoing an eyewall replacement cycle, where the inner eye of the storm collapses and is replaced by a larger, outer eye. During these internal cycles, max wind speeds often decrease and fluctuate before the storm consolidates a new eye. It has been downgraded to a Category 4 storm with maximum sustained winds of 150 mph.

Headlines

  • Landfall somewhere in South Florida over the weekend is a near certainty. Outer bands from Irma are expected to reach South Florida overnight tonight. Life-threatening storm surge inundation and damage from winds of major hurricane force (115 mph) are a near-certainty for parts of South Florida.
  • Since midday yesterday, forecast models have trended slight back towards a westerly solution for the forecast track of the storm. This almost eliminates the risks to Georgia and South Carolina coastal areas from a direct hit from a major hurricane. However, the risk to these areas from storm surge and strong tropical storm force/marginal hurricane force winds still exists.
  • There is still a chance Irma could make landfall on Cuba. This would weaken the storm ahead of subsequent landfall on Florida.

Forecast Track

As mentioned above, the best performing forecast models have shifted back to a more westerly track for Hurricane Irma.

Several different forecast models take on Irma’s track.
Official National Hurricane Center forecast as of 8AM today.

Forecast Intensity

While Irma has weakened to a Category 4 storm due to an ongoing eyewall replacement cycle, it remains an extremely dangerous storm with an expanding wind field due to this cycle. Hurricane force winds extend 70 miles on each side of the eye and tropical storm force winds well beyond that. It remains possible that Irma can re-strengthen if it completes the eyewall replacement cycle before it interacts with land. Mid-level wind shear remains negligible and Irma will soon be passing over very warm seas with increasing depth. Both of these factors would suggest it maintaining Category 4 strength or possibly re-intensifying to Category 5.

Uncertainties

  • Any landfall on Cuba or interaction of the core of the storm with the high mountains of that island would disrupt the storm and cause weakening. This would be good news for Florida, at the expense of Cuba of course.
  • Should the core of the storm avoid Cuba and close off a new eye before too much time elapses, it would have the possibility of re-strengthening before landfall. A strong Category 4 or even a Category 5 storm making landfall on Florida is not out of the question.

Hurricane Irma Special Update – Sep 7, 2017

This is one of an upcoming series of special posts dedicated to Hurricane Irma. I’m hoping these posts will keep those of you who are either in areas at risk or have friends and family there informed and prepared as this historic storm bears down on the US mainland.

Current Situation

Hurricane Irma remains an impressive Category 5 storm packing sustained wind speeds of 175 mph. It is nearing the Turks and Caicos Islands as of this time.

Headlines

  • The threat Irma poses to South Florida as a strong Category 4 storm continues to increase
  • There is a risk to the Georgia and South Carolina Coasts. This risk would increase if there’s eastward movement of the storm track, as was the case in previous track forecasts.
  • Major impacts are expected to the Turks and Caicos and Bahamas archipelagos
  • The threat to the northern coast of Cuba remains high. Hurricane watches have been upgraded to warnings.
  • This is a large hurricane – the larger the size of the storm, the larger the storm surge it can generate. Even if the eye of the storm misses Florida to the east, the entire state could still feel the impacts of tropical storm and hurricane force winds.

Forecast Track

Here is the National Hurricane Center’s latest official forecast with a 5-day cone of uncertainty reflecting the spread in forecast models. Models have been wavering between a more westerly and easterly track in the past 24 hours which would have big implications (see below).

Here are some actual forecast model outputs on the storm’s track.

 

GFS model run showing Irma very close to or making landfall on the Miami area on Sunday at 8AM

 

Forecast Intensity

Unless the core of the storm interacts with the high terrain of Cuba by making landfall on it, it is unlikely that Irma would weaken significantly.

Wind shear is expected to remain low at the mid-levels, which means basically zero disruption to the core of the storm. Sea surface temperatures are very warm in the Florida Straits and Bahamas. This will support the storm maintaining itself as a very powerful hurricane.

Irma is expected to approach South Florida as a dangerous Category 4 storm (sustained winds over 130 mph). Even with some interaction with Florida, Georgia and South Carolina could still expect a strong Category 2 (sustained winds > 95 mph) or a Category 3 (sustained winds > 115 mph).

 

Uncertainties

The critical component of forecast track uncertainty is the timing and degree of influence a mid-level trough (the dip in that solid black line in the image below) on initiating Irma to begin a turn to the north as it rounds the western periphery of the Bermuda high that has been steering it thus far. The effect of a mid-level trough is both to weaken the Bermuda high and also to exert a pull on Irma to the north.

 

The timing of Irma’s northward turn is significant as an earlier turn would result in a more easterly track, and a later turn would result in a more westerly track. A small deviation either way could either spare an area from a direct hit by the devastating eye of the storm or bring it right into the eye.

  • A track to the east that takes the center of the storm away from South Florida would result in a stronger impact on the Georgia/South Carolina coasts
  • A track to the west would reduce the possible dangers to Georgia and South Carolina but increase the threat to the entire Florida Peninsula. This would still result in serious impacts to South Florida.
  • Another factor to consider is that landfall on Cuba and any significant interaction of the core of the storm with the high mountains of Cuba would result in a weaker storm affecting Florida and other US locales

 

Irma’s Impacts Thus Far

Overnight into today, Hurricane Irma made landfall on several small Leeward Islands including Barbuda and Saint-Martin/Sint-Maarten. These islands took a direct hit from the eyewall of Irma, which packed sustained winds of 185 mph. This resulted in catastrophic damage to Barbuda that the prime minister described as rendering the island barely habitable. Below, you can watch some footage captured by a camera at Princess Juliana International Airport located in Sint-Maarten, the Dutch side of Saint Martin as the eyewall impacted that location.

As on Barbuda, scenes of widespread damage were to be found on Sint-Maarten as well. Here’s an infrared satellite image of Irma as its eye swallowed Anguilla and Saint-Martin/Sint-Maarten last night:

Hurricane Irma has smashed an all-time record for longest duration of winds at 185 mph in the satellite era (1970s or so onward) with these winds lasting for 36 hours. This is truly incredible considering that the strongest tropical cyclones are typically found in the Western Pacific where these storms have ample time over warm water to grow.

NYC Weather Update and Hurricane Irma – Sep 4, 2017

The unofficial end of summer does indeed bring us a last gasp of summery weather. A cold front passing through mid-week brings rain and signals a return to more fall-like conditions. Later in the week, we will see high temperatures 5°F below normal. Turning towards the tropics, the risk Irma poses to our region is diminishing, but it now appears Irma will be a threat to Florida.

Rest of today – clear, with ideal conditions for outdoor activities of all kinds. High temperatures in the low-80s.

Tuesday – highs in the low-mid 80s as warm air surges ahead of an advancing cold front. Mostly sunny with increasing clouds late in the day. Some possibility for a spot shower or thunderstorm in the afternoon.

Wednesday – thunderstorms are possible overnight Tuesday as the leading edge of the cold front advances through the area. More rain is expected to ride along the frontal boundary after it passes through, bringing periods of showers throughout the day. High temperatures will be much cooler in the mid-70s with the clouds and rain.

Thursday – mostly cloudy to start with a chance for lingering rain. High temperatures will be cool again in the low-70s.

Friday – mostly sunny skies, much improved conditions as high pressure takes hold. Cool, with high temperatures in the low-70s.

 

Hurricane Irma an Increasing Threat to Florida

Over the weekend, Irma has been fluctuating in strengthen as it has negotiated marginal conditions for strengthening (mostly the influence of some dry air at upper levels). The National Hurricane Center still forecasts Irma to attain Category 4 strength at some point later this week (130 mph sustained winds or higher) as it encounters more favorable conditions for strengthening, and maintain at least Category 3 strengthen (sustained winds > 115 mph) throughout the forecast period.

The track forecast for Irma has continuously shifted west and south over the weekend due to the influence of an area of high pressure over the Atlantic now, and a faster forecast for the passage of the cold front mentioned above. This frontal boundary lifting out of the East Coast at a faster rate than in prior forecasts would mean that it does not influence Irma to make a turn to the north-northwest and threaten the East Coast. This has two consequences: 1) The chance for Irma to make landfall up the East Coast is diminishing, 2) On the other hand, the risk to Florida is increasing.

This run of the GFS forecast model suggests Irma making landfall on South Florida as a powerful Category 3 hurricane in one week’s time.
A “spaghetti” plot of multiple model runs of GEFS, one of the forecast models that forecasters are using to analyze Irma.

It is important to note that with a week to go before Irma nears the US mainland, there could still be room for changes to the track and intensity forecasts. The National Hurricane Center specifically cautions against drawing premature conclusions about the storm’s impact on the rest of the US, while singling out Florida as an area of concern. More updates to come as we continue to watch the development of what could be a very dangerous storm.

NYC Weather Update – Aug 28, 2017

Nice weather from the weekend continues today. Chance for rain on Tuesday. Temperatures remain below normal through the week except Thursday. Labor Day weekend looks to start off like autumn.

Rest of today – clouds this morning expected to dissipate somewhat. Below normal temperatures with highs in the upper-70s.

Tuesday – a disturbance off the coast of northeast Florida has the potential to develop into Tropical Storm Irma. Regardless of whether the storm successfully undergoes tropical cyclogenesis, it is still anticipated to bring us some tangible weather impacts. This would be in the form of some rain especially later in the day as it makes a transition to an extra-tropical storm.

Easterly onshore winds from this storm to our south will suppress high temperatures in the low-70s and give us a mostly cloudy day.

Wednesday – unlike Tropical Storm Harvey, the storm above will accelerate quickly out to the Atlantic, so Wednesday should turn out to be a pretty decent day with mostly sunny skies and temperatures rebounding back to the upper-70s.

Thursday – a cold front will pass through the area during the day and could trigger a few scattered thunderstorms. Warmer air ahead of the cold front should give us about average high temperatures in the low-80s.

 

Peak Hurricane Season

We’re on the cusp of the traditional peak of the Atlantic Hurricane season, which typically begins around late August and lasts through till late September. This period typically sees the highest oceanic surface temperatures (due to the specific heat of water being relatively high, there’s a lag in time between peak solar heating of summer and actual peak ocean temperatures), which in ups the potential for tropical cyclone development.

Not surprisingly, we’ve got Harvey still devastating the Texas coast, about to re-emerge over open water before making a second landfall later this week. We’ve also got a possible tropical cyclone off of the Southeast coast and another tropical wave moving offshore of Africa that could develop into a tropical storm as it moves west. A lot of activity to monitor, hoping that none of it comes our way!

NYC Weekend Weather + Note on Harvey – Aug 25, 2017

I’ve returned from Europe (missed the eclipse though!) to a very pleasant stretch of calm weather and slightly below normal temperatures. Surface high pressure to our northwest over Ontario will continue to bring us cool, dry Canadian air that evokes a more fall-like feel.

Rest of today – just about normal temperatures with highs around 80°F, skies have cleared up nicely and we should have spectacular weather for the start of the weekend.

Saturday – high pressure remains in control, and gives us another pristine day of slightly below normal temperatures in the upper-70s but lots of sun.

Sunday – basically a clone of Saturday, high temperatures in the upper-70s, lots of sun.

Monday – more of the same with temperatures again in the upper-70s, maybe a few more clouds, but who can complain especially when you consider the next section.

 

Hurricane Harvey a Major Threat to the Texas Coast

It’s worth mentioning here that we have a very dangerous situation developing on the Texas coast today and over the course of the next few days with Hurricane Harvey. If you have friends or family in this area, it’s not a bad idea just to try and check in with them.

GOES 16 visible satellite image of Harvey showing impressive size, distinctive eye, decent symmetrical outflow except on the side already beginning to interact with land.

Harvey originally formed over the eastern Caribbean, dissipated approaching the Yucatan, and then redeveloped as it emerged over the Bay of Campeche. Favorable conditions have allowed Harvey to strengthen quickly into a Category 2 storm, and it’s forecast to continue strengthening to Category 3 before landfall.

This would make it the first major hurricane to make landfall on the US mainland in nearly 12 years. The biggest concern with Harvey is that most forecast models have the storm stalling out after landfall, and possibly looping back out to the Gulf and making a second landfall mid-week next week in eastern Texas, still retaining tropical storm strength. Two areas of upper-level high pressure will essentially be trapping Harvey in place.

The slowing forward motion of the storm means that tropical storm and hurricane force winds will rage for many hours. The longer the winds churn up the waters of the gulf, the bigger the life-threatening storm surge along the coast. Peak storm surge of 6-12′ is forecast. That’s without waves on top. For reference, Sandy brought a peak storm surge of 14′ to The Battery. That’s well above the first, and well into the second story of most homes. On top of that, rainfall totals measuring 2-3′ are possible, which would cause widespread inland flooding.

NYC Weather Update – Dec 28, 2015

After an absurdly warm start to the winter, we are about to get a dose of proper weather for this time of year. While temperatures this week and the first half of January will still above normal in many cases, they will be considerably cooler than December and be closer to normal than not. This week, we start with a messy and complex storm (the same that spawned deadly tornadoes in Texas and has brought blizzard conditions to New Mexico, and an ice storm to Oklahoma) that affects the area tonight into Tuesday with a mix of rain, sleet, freezing rain, and snow, depending on how far north you are. Yet another round rain and snow further north from the city is possible Wednesday.

Rest of today – seasonably cool with high temperatures only in the low-mid 40s. Increasing clouds ahead of a warm front that will be the focus for the precipitation later tonight. Things get interesting overnight as precipitation begins to spread over the area from southwest to northeast. Near the coast, surface temperatures are expected to remain warm enough (upper-30s) to largely preclude the possibility of significant wintry precipitation, however, sleet could mix in with rain to at the start of this storm before things shift over to all rain. Further west and north will be another story, with areas expecting anything between .25″ of ice to 2-4″ of snow/sleet accumulation before rain starts falling.

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Tuesday – as temperatures warm with daybreak, wintry precipitation should transition entirely to rain. Rain is expected to last throughout most of the morning into the early afternoon hours. East winds ahead of the warm front mentioned above will be in the 15-20mph range before shifting to the north. High temperatures in the city are expected to hit the upper-40s to around 50ºF.

Wednesday – we’ll get another shot at rain as the cold front railing the warm front pictured above pushes through late on Wednesday into the overnight hours. Despite increasing clouds, forecasts still call for high temperatures in the low-50s.

Thursday – a lingering chance of rain remains on the backside of the cold front. High temperatures are expected to be about the same as Wednesday near 50.

NYC Weather Update – Aug 23, 2015

A slow moving cold front brings an unsettled start to the week. Ahead of this cold front, temperatures will rise along with humidity, leading to a late-summer feel. Once this frontal boundary passes, high pressure to the west will allow for a cooler, drier Canadian airmass to enter the region, leading to more seasonable temperatures along with sunny skies.

Rest of today – a mix of sun and clouds continues with a small chance of some rain, with temperatures topping out around average in the low-80s.

Monday – as a cold front approaches from the west, humidity and temperatures will rise along with a south wind. There is some small chance for thunderstorms, especially west of the Hudson. Otherwise, expect a mix of sun and clouds with temperatures in the mid-80s.

Tuesday – with the cold front lingering in our vicinity, a small chance for showers and thunderstorms continues, along with warm and humid temperatures in the mid-upper 80s.

gfs_namer_039_1000_850_thick

Wednesday – the cold front finally pushes through Tuesday, and gives way to high pressure building in from the west on Wednesday. This will lead to comfortable temperatures in the low-80s with sunny skies.

Thursday – similar conditions to Wednesday, with sunny skies and a pleasant, comfortable high in the low-80s.

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A Note on the Tropics

We’re about to enter the most active period of the Atlantic hurricane season, and things have definitely picked up in the tropics. A series of monsoonal tropical waves are moving off of the cost of West Africa, giving rise to the potential for a couple of Cape Verde type tropical cyclones. This conveyor belt of tropical waves has already spawned this season’s first hurricane, Danny, which peaked as a major hurricane with winds of 115mph (Category 3) at the end of last week. Danny has weakened considerably, but could still bring some much needed rain to Hispaniola and Puerto Rico in the next couple days. Meanwhile, another tropical wave following on Danny’s footsteps could become Tropical Storm Erika in the coming days. Neither of these storms poses any immediate threat to the United States for the time being.

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NYC Weather Update & TS Bill – Jun 16, 2015

We’ve certainly seen plenty of rain during the month of June, yet the NYC region remains in an area of moderate drought as of last Thursday. However, this does not reflect the rain that fell overnight Sunday into Monday. After a gloomy start to the week, we get a break of decent weather tomorrow, before another possible round of rain Thursday. The week ends with some drying out and improving conditions.

Rest of today – highs should top out in the upper-70s to around 80 today, with the potential for showers and thunderstorms later this afternoon. Storms have already formed to our west over northeastern Pennsylvania, but there is a stabilizing marine air layer over NYC and points east, so these storms may yet break apart before reaching us.

 

High Resolution Rapid Refresh model simulated radar for 1PM today.
High Resolution Rapid Refresh model simulated radar for 1PM today.

Wednesday – skies will clear rapidly overnight and lead to a sunny, dry, and pleasant day on Wednesday. Highs should be near 80. The high pressure creating these pleasant conditions will not stay around long, as another warm front approaches from the west.

Thursday – will look a lot like today, with mostly cloudy skies, and a potential for showers and thunderstorms in the afternoon as a warm front nears the region. Highs will be a bit cooler in the mid-70s with the influence of clouds and a southeasterly flow off the ocean ahead of the warm front.

Friday – the warm front from Thursday is followed quickly by a cold front passing Friday morning. Behind this, high pressure takes control and brings decent weather for the first half of the weekend. Highs Friday should be in the low-80s with clouds and sun.

 

Tropical Storm Bill

Over the weekend, a disturbance organized over the western Gulf of Mexico, and by last night it had consolidated and intensified enough to be designated the 2015 Atlantic Hurricane Season’s second named tropical cyclone – Tropical Storm Bill. Bill will be making landfall imminently in Texas as a moderate strength tropical storm with maximum sustained winds of 60mph.

Satellite image of Tropical Storm Bill about to make landfall on the central Texas Gulf Coast
Satellite image of Tropical Storm Bill about to make landfall on the central Texas Gulf Coast

However, for people living in the path of Bill, it is not the wind but rather the potential for dangerous flash flooding that is the primary concern with this storm. Bill is forecast to bring as much as 10″ of rain over the next few days to parts of Texas, and upwards of 6″ for a wide swath of Oklahoma and Missouri. As you may recall, some of these areas were the scene of deadly flooding just a few weeks back, and the arrival of a rainmaker like Bill is most unwelcome for these areas that are still in the midst of recovering. Moisture from Bill will eventually work its way into our region, but in a much less intense way.

Forecast rainfall totals for TS Bill
Forecast rainfall totals for TS Bill