Tag Archives: tropical storms

NYC Weekend Weather – May 15, 2020

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We have summery temperatures in the low-80s to start the weekend. Some storms are possible overnight as a cold front swings through. Saturday sets up to be another nice day with high pressure building. Sunny skies and more seasonable temperatures in the mid-70s. By Sunday, a storm system approaches bringing possible showers. Next week, we may see a prolonged period of wet weather, in part affected by tropical moisture from a potential Tropical Storm Arthur.

Rest of today – a warm front has already pushed through the area earlier this morning. Warm, southwesterly winds will help temperatures rise well into the upper-70s and low-80s. Clouds are likely to increase as a cold front approaches slowly from the northwest. Overnight lows in the low-60s as the cold front moves through, bringing low chances for showers and thunderstorms.

Weather Prediction Center surface forecast for 8PM Saturday

Saturday – high pressure builds in behind this cold front. This should yield a sunny day with high temperatures in the mid-70s. Overnight lows in the low-50s.

Sunday – a storm system will be approaching from the west. Rain chances will increase late with mostly cloudy skies and cooler temperatures in the mid-60s. Overnight lows in the low-50s.

Monday – rain chances continue due to the influences explained below. High temperatures remain cool, in the low-60s, with mostly cloudy skies expected. Overnight lows in the low-50s.

Potential Subtropical or Tropical Storm Arthur’s Impact on Our Weather

Next week, we may be in for an extended period of dreary, wet weather as the storm system mentioned above interacts with a potential tropical storm that’s currently forming over the Florida Straits. Actually, regardless of whether this becomes a full-fledged tropical or subtropical storm (which would be named Arthur, and the first named storm of the 2020 Atlantic Hurricane Season), it would still have the potential to bring tropical moisture our way. The interaction between these two storm systems, plus the forecast for a an area of blocking high pressure forming north of them means that we could see chances for rain well into mid-week next week.

  • National Hurricane Center’s forecast outlook for the Atlantic Basin, showing an 80% chance for a disturbance over the Florida Straits to become a subtropical or tropical cyclone
  • GFS model 1000-500 mb thickness, surface pressure, and precipitation for Tuesday, showing this offshore storm interacting with one over land
  • GFS model 4-panel prog valid for 8PM Sunday, showing conditions favorable for tropical cyclogenesis: low wind shear, high vorticity, and decently moist low-mid levels.

NYC Weekend Weather – Oct 25, 2019

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This weekend starts off with fair and dry weather. A storm developing along the Gulf Coast of Texas, tracking north along the Mississippi and Ohio Valleys into the Great Lakes, then east towards our area will bring a prolonged period of steady rain on Sunday. As of 11AM today, National Hurricane Center has designated this storm as Tropical Depression Seventeen. This storm should pull out of the area before the start of next week. Temperatures during this period should be at or above average for this time of the year in the low-mid 60s.

Rest of today – partly sunny to mostly cloudy with a cold front weakening, then stalling and returning north as a warm front. High temperatures in the mid-60s. Overnight lows in the low-50s with decreasing clouds as high pressure builds in.

Weather Prediction Center surface forecast for 8AM Saturday

Saturday – high pressure builds briefly and should give us mostly sunny skies with high temperatures in the mid-60s. Overnight lows in the low-50s with increasing clouds and chances for rain.

Sunday – much like last weekend, a storm with tropical origins will bring rain and lots of moisture to the area. The extratropical remnants of Tropical Depression Seventeen will track north towards the Great Lakes during this period. A warm front attached to it will bring a shield of steady stratiform rain over the area. Mostly cloudy with highs in the upper-60s as winds turn to the south. Steady rain continuing into the early overnight hours until the storm’s trailing cold front finally sweeps through and drier air works in. Lows in the mid-50s.

  • NAM model output for relative humidity and wind at 850 mb for 5PM Sunday. Note the nearly saturated nature of the lower levels of the atmosphere.
  • NAM model output for wind at 850 mb for 5PM Sunday. Note the high wind speeds at this level, indicating the presence of an 850 mb low-level jet (LLJ)
  • NAM model output for precipitable water at 2PM Sunday. Note the high values above 1.50″. This makes sense, given the tropical origins of the storm that will impact us Sunday.
  • Projected track of Tropical Depression Seventeen

Monday – high pressure and calmer conditions return with highs in the mid-60s and mostly sunny skies. Overnight lows in the mid-50s with mostly cloudy skies.

NYC Weather Update – Sep 4, 2018

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A brief break in the heat over the weekend has led back into another warm spell to begin this week. This latest blast of heat will be short-lived as a backdoor cold front sweeps through tomorrow, followed by another, stronger cold front later this week. Temperatures for the upcoming weekend will once again be comfortable, seasonable to below average. In the tropics, things are starting to get busy with tropical storms Florence and Gordon active and another tropical wave poised to become a tropical cyclone off the coast of Africa. Gordon will make landfall overnight on the Gulf Coast east of New Orleans.

Rest of today – hot and humid with temperatures in the low-90s, mostly sunny skies.

Wednesday – cooler, though still warm with high temperatures in the upper-80s and partly sunny skies. A backdoor cold front will bring cooling onshore southeasterly breezes that help keep a lid on temperatures.

Thursday – temperatures rise back a couple degrees into the low-90s ahead of an approaching cold front from the northwest. The warm air ahead of the cold front could help set the stage for a few scattered strong thunderstorms as the front passes through.

Friday – temperatures cool off quite a bit into the low-80s under mostly cloudy skies. Chance of showers during the day with the cold front lingering south of the area.

Tropics Heating Up

We have 2 active tropical cyclones (Florence, Gordon), and another incipient one in the Atlantic Basin. Tropical Storm Gordon could strengthen into a hurricane before landfall on the Gulf Coast between Mississippi/Alabama overnight into Wednesday. Heavy rain could induce flash flooding in southern portions of these states. The immediate coastline will be at risk of storm surge flooding. Florence doesn’t pose an threat to land. The disturbance shown below that’s furthest east is a tropical wave that’s just emerged off the coast of Africa. This is worth watching as it has a high chance of becoming a tropical cyclone and its eventual track could pose a threat to portions of the Lesser Antilles.

NYC Weather Update – Sep 11, 2017

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We will start this week that marks the 16th anniversary of the 9/11 attacks with excellent and seasonably warm temperatures in the low-80s for memorial services today. The pleasant weather should hold up through Thursday before the remnants of Irma begin to move into the region. Looking ahead, some forecast models have hinted that Hurricane Jose poses a possible risk to the East Coast.

Rest of today – pleasant, mild conditions with mostly sunny skies and high temperatures in the low-80s.

Tuesday – mostly sunny skies again with high temperatures much the same as today in the low-80s. High pressure will be in control of our weather during this period.

Wednesday – clouds begin to build in conjunction with the northward movement of the expansive cloud shield associated with Irma well to the south. This will cause temperatures to dip just a bit to about 80°F.

Thursday –  a touch warmer, mostly cloudy skies, high temperatures in the low-80s.

 

Hurricane Irma and Jose Updates

Residents of Florida’s west coast avoided what looked like it could be a worst case scenario for them. Irma weakened faster than forecast and moved just far enough inland such that the strongest winds of the eye did not hit Tampa. The weaker storm also reduced the risk of serious storm surge. Still, as you’ve probably seen from media reports, damage from the storm is widespread and of varying degrees of severity across the state. The dangers of the storm now move inland, with heavy rain and tropical storm winds into the Southeast.

While Irma spins down over the Southeast, Jose remains a wildcard for the East Coast next week. Several runs of the GFS have suggested a landfall for Jose somewhere in the Mid-Atlantic or Northeast. It’s far too early to know with any degree of certainty whether this scenario will pan out, since a lot of other forecast models show Jose curving out to sea, but it will bear watching.

Hurricane Irma Special Update – Sep 7, 2017

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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 Weekend Weather – Aug 4, 2017

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A hot week transitions into a weekend that will see the end of the heat and humidity for at least half of next week and maybe longer. Rain and thunderstorms dot the forecast except appropriately Sunday.

Rest of today – partly sunny with high temperatures in the mid-80s. The rain and thunderstorms this morning give way to a dry day otherwise.

Saturday – a warm front moves through overnight into the morning with a cold front following right on its heels. This will bring a period thunderstorms producing heavy rain at times. Marginally favorable atmospheric conditions could spawn a few strong storms. Clouds clear up in the afternoon and highs are expected to reach normal levels in the mid-80s.

Sunday – cooler, drier air moves in behind the cold front Saturday. High pressure builds to the south and west and moves south sending cooler Canadian air around its periphery towards us. High temperatures will be comfortable around 80°F with lots of sun.

Monday – a weak disturbance brings rain and cooler temperatures, well below average only in the mid-upper 70s.

Trouble in the Tropics?

A vigorous tropical wave has spun up off the west African coast and Cabo Verde. Storms originating from this region have historically been some of the most powerful and damaging, but that’s if they can sustain the transit across the Atlantic. The National Hurricane Center has this wave at a 50% of forming into a tropical depression or storm in 2 days, and 80% chance in 5 days. It’s worrying that it’s starting to get picked up on long-term GFS model runs taking a swipe at the US East Coast as a strong tropical cyclone, however, this far out, it’s difficult to say which one of many scenarios could play out. It does bear monitoring though.

GFS for Wednesday 8/16, with the tropical system in the picture right off the East Coast of the US.

NYC Weekend Weather – Apr 21, 2017

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A cool and dreary end of the week leads into a continued stretch of slightly below average temperatures for the weekend. Temperatures remain on the cool side with chances for rain to start next week before a warm up in the second half of next week. Far off in the Central Atlantic, a rare April tropical storm (Arlene) has formed.

Rest of today – rains moved through overnight and lingering showers this morning should end within the next couple hours. Cloudy with high temperatures only in the upper-50s to around 60°F.

Saturday – despite winds turning to the north with high pressure moving in from the west, temperatures should still rebound into the low-60s. Partly to mostly cloudy skies.

Sunday – mostly cloudy to overcast with temperatures hovering around 60°F.

Monday – the next chance for rain comes in along with a developing coastal low that lingers through Tuesday. Timing of this coastal storm remains somewhat uncertain, so it could end up being somewhat of a pest early next week.

 

Rare April Tropical Storm
We’re still 2 full months off from the official start of the 2017 Atlantic hurricane season, which makes the formation of the first named storm of the season even more of a meteorological oddity. Tropical Storm Arlene will spend its life churning up the waters of the Central Atlantic without any impacts on land. It’s still worth noting that this is only the second time since the dawn of the satellite era that a tropical storm has been detected in April.

TS Arlene is the tight circulation located at around 50° W, 40° N

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.

GOES16152016248Zv6rCK
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.

144502
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.

144502W5_NL_sm

Will be posting another update tomorrow.

 

 

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.

gfs_namer_057_1000_850_thick

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

Tropical Weather Update | Typhoon Hagupit – Dec 5, 2014

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A potent and massive typhoon is taking aim at the northern Philippines, in particular, Samar Island. Some of these areas were devastated by Category 5 Super Typhoon Haiyan less than one year ago, which broke the record for strongest landfalling tropical cyclone with wind speeds measured in Tacloban of 190mph. If you have friends or family in the Northern Philippines, Hagupit certainly bears keeping an eye on. Luckily for Tacloban, the current forecast track should take the center and northern semicircle (the stronger portion) of the storm north of the area, which should spare the area worst hit by Haiyan from another direct hit and the worst effects of a typhoon.

wp201422_sat
Infrared satellite imagery of Typhoon Hagupit – note the symmetrical appearance of the inner portion of the storm, along with a well-defined eye (classic signs of a very strong storm).

Forecast Track

From the image below, you’ll see that Hagupit is currently forecast to move slowly west-northwestwards over the next 48 hours. Due to the strength of the storm, and the uncertainty surrounding the steering mechanisms in place (a subtropical ridge – high pressure area to the north weakening, and a frontal boundary), there is a low degree of confidence over the overall track forecast. However, it does appear, even with the uncertainty factored in that the storm center will pass to the north of Leyte Island and Tacloban, which was devastated by Super Typhoon Haiyan. That’s good news, since this would mean the weaker, southern semicircle of Hagupit would pass over the Leyte Gulf area. This would significantly reduce the effect of a devastating storm surge, since the winds from the storm would not have the best fetch (distance over open water) to build up a storm surge. In effect, with the current track, the strongest winds would be deflected by the terrain of Samar Island, sparing Leyte Island.

It is worth noting, based on this current track, that Legazpi City in extreme southeastern Luzon Island would bear the worst of the storm, including what could be a devastating storm surge. The bay east of Legazpi could serve to funnel storm surge westward under the right conditions, amplifying the effect of the surge in a similar (though less intense) manner as Leyte Gulf and San Pedro and San Pablo Bay did for Tacloban in Haiyan.

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Haiyan_2013_track
For comparison, the track of Super Typhoon Haiyan in November 2013. Dots indicate position of the center of the storm every 6 hours, the colors indicate strength, with red indicating Category 5.

Intensity Forecast

Typhoon Hagupit has well-established outflow in the northern quadrant, as you can see from the satellite image above (white streaks fanning out from the center of the storm). It is being affected by easterly vertical wind shear, hence the absence of the same outflow bands in that sector of the storm. Hagupit has already weakened from a Category 5 Super Typhoon, but is still forecast to approach the Philippines as either a strong Category 3 or weak Category 4 storm, which would mean wind speeds likely in the range of 110-120mph. After landfall, Hagupit should weaken dramatically as interaction with the mountainous terrain of the Philippines disrupts the typhoon’s dynamics.