Category Archives: Outside of NYC

NYC Weekend Weather – Jun 4, 2015

We have struggled to reach normal temperatures this week, with plenty of rain and Wednesday as the only sunny break. We end this week with more cool, damp weather, before transitioning to warmer, drier conditions this weekend. Portions of the area received anywhere between 2-4″ of rain between Sunday night and Tuesday night, which will help improve drought conditions, however, these rainfall totals also led to flash flooding across large portions of the area.

Rest of today – cloudy, with a small chance for isolated light showers, cool with temperatures topping out only in the low-mid 60s, about 10ºF below normal for this time of year.

Atmospheric setup favoring the cool, cloudy, damp weather
Atmospheric setup favoring the cool, cloudy, damp weather

Friday – more clouds and cool weather, with this easterly onshore flow regime sticking around for one more day. High temperatures will again be only in the mid-60s, much below normal. There is a slightly higher chance Friday for scattered showers, but nothing like the soaking we got earlier this week.

Saturday – some improvement in conditions will take place Saturday as high pressure starts building from the west. Partly sunny skies may give way to more sun, with high temperatures warmer near 80.

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Sunday – high pressure moves to our east, allowing us to enjoy another pleasant, dry day, with high temperatures in the mid-70s.

Monday – a frontal system approaches the area. Ahead of the front, warmer air will flow in from the southwest, giving us temperatures at or above normal near 80ºF. As the front nears, thunderstorms and showers are possible across the region.

 

Arctic Jet Stream Slowing Leading to Increased Incidence and Duration of Extreme Weather? 

The massive quantities of snow that fell over the Northeast this past winter, the flooding rains over Texas last month, the enduring drought over California, and the asphalt-melting heatwave in India have all raised the question of what is causing this apparently increased incidence of long-duration extreme weather events. One possible explanation offered by researchers at Rutgers University is that the polar jet stream circling the Arctic has been slowing.

Jet streams are generated by two factors: the rotational energy of the Earth spinning on its axis, and the pressure gradient between two airmasses of varying temperatures. In the case of the polar jet circling the Arctic, rapid warming of the Arctic over the last couple decades has led to a decreased thermal and pressure gradient between air over the Arctic and air directly to the south. Researchers posit that this effect has led to a slowing of the polar jet stream. Since the jet stream is responsible for moving large (synoptic) scale weather patterns, any affect on its speed and orientation can have dramatic impacts for widespread regions of the world. In this case, the slowing polar jet stream is theorized as the mechanism behind the prolonged effects of the weather events mentioned above.

NYC Weekend Weather – May 8, 2015

Another splendid weekend is in store for us with warm temperatures in the upper-70s and near 80. Subtropical Storm Ana marks the first named storm of the 2015 Atlantic Hurricane Season. It is not expected to bring us any direct impacts, however, it could bring moisture our way that could supplement a storm system forecast to pass through early next week.

Rest of today – early fog has burned off, skies have cleared, and temperatures should top out near 80. We have been under the persistent influence of a high pressure center that has been responsible for pumping in this warm, moist air from the south.

Saturday – clouds and sun, with sunny breaks more likely to appear near the coast in the afternoon. High temperatures should be a bit cooler in the mid-70s with the influence of clouds, however, any sunny breaks could easily shoot temperatures up a few degrees.

Sunday – once again, Sunday comes through as the best day of the weekend, with mostly sunny skies and highs in the low-80s.USA_East

Monday – clouds for the most part as a frontal boundary approaches from our north and west. High temperatures will still be quite mild with the influence of high pressure bringing southerly winds, expecting a high again near 80. Some chance for afternoon thunderstorms to develop as that frontal boundary nears.

Tuesday – probably our best shot at getting measurable rainfall as the aforementioned front passes through. Some left over moisture from Ana could work its way into this setup. Ahead of the front, temperatures should still rise into the upper-70s. It’ll be noticeably cooler for the second half of the week.

 

Subtropical Storm Ana

We have our first named storm of the 2015 Atlantic Hurricane Season which doesn’t officially begin until June 1st. Subtropical Storm Ana developed out of a weak tropical disturbance off of Florida. This just goes to show, a tropical cyclone can form under the right conditions at any time of the year.

Visible satellite loop of Subtropical Storm Ana this morning - Geostationary Satellite Server
Visible satellite loop of Subtropical Storm Ana this morning – Geostationary Satellite Server

Subtropical Storm Ana fortunately does not have much time to organize and intensify before it makes landfall on the coast of the Carolinas. This should limit any serious damage, however, these areas will likely experience prolonged high winds, torrential rain, and coastal flooding.

Global Forecast System ensemble forecast tracks for Ana
Global Forecast System ensemble forecast tracks for Ana

NYC Weather Update – May 6, 2015

A downright summer-like stretch of weather that started this week will get mirrored again towards the end of this week and going into next week. After clearing out clouds today, the remainder of this week should see dry and sunnier weather with highs in the mid-upper 70s. This weekend, we are looking at the possibility of temperatures near 80, nearly 15º above normal. We also have what could turn into the 2015 season’s first tropical depression/storm churning up off the coast of Florida now.

Rest of today – a very slow-moving, largely stationary front pushed through last night, but is still sitting in our vicinity. Along this front, remnants of more organized convective activity will be able to slide east during this afternoon and evening. While the chances are not high, there could still be an occasional shower during the latter half of today, high temperatures will be somewhat subdued around 70 with the clouds in place.

Thursday – clouds will clear out tomorrow and we should have a sunny day with temperatures in the mid-70s.

Friday – a repeat of Thursday, with mostly sunny skies and highs again in the mid-70s.

Saturday – increasing cloud cover, but should still be a pleasant day with temperatures in the upper 70s.

Sandwiched between rain to our south and to our west, but our weather should still remain dry this weekend.
Sandwiched between rain to our south and to our west, but our weather should still remain dry this weekend.

Sunday – warm and pleasant with a high near 80.

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Climate Prediction Center temperature outlook for next week – still looks like we’ll be getting warmer than normal temps

First Tropical System of the 2015 Atlantic Hurricane Season?

As I write this, a low pressure system is building up steadily off the east coast of Florida. The National Hurricane Center puts the odds of this system organizing sufficiently to become the first named tropical depression, subtropical, or tropical storm of the 2015 Atlantic Hurricane Season. Even if this storm does become the first named tropical system, it is unlikely to do much damage as it will have very little time over open water to gain strength before it is forecast to make landfall over the Carolinas later. The most noticeable impact from this storm would be the rain it generates.

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Tropical Weather Update | Typhoon Hagupit – Dec 5, 2014

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.

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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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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.

NYC Weekend Weather & West Coast Storm – Dec 2, 2014

It’s been a up and down week for weather in NYC, with Monday starting out in the mid-60s, then a colder mid-week that featured some mixed precipitation and rain. The end of this week will feature rain and slightly warmer temperatures by Saturday, then a return to colder conditions Sunday into next week. I’m also going to point out some of the spectacular weather brought on by a huge Pacific storm that hit California this week.

Thursday – the remainder of today will be pleasant and sunny, though cold with high temps only in the low 40s.

Friday – clouds will begin to build overnight tonight ahead of the a storm system moving in from the Southern Plains to the Ohio Valley. There is a small chance for scattered showers, otherwise expecting a cloudy day with highs in the mid-40s.

Saturday – rain should overspread the area by Friday night into Saturday. This storm system will be drawing on energy and moisture from the Pacific storm that slammed California earlier this week (discussed below). Combined with influx of Gulf moisture, this setup favors a moderate to at times heavy rain event for Saturday. Temperatures will rise steadily ahead of this storm system as it pushes warm air up. High temperatures Saturday should reach into the mid-50s despite rain and clouds.

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GFS model output for overnight Friday into Saturday

Sunday – rain should end overnight Saturday, and high pressure from Canada should quickly build in behind this storm system. The positioning of this high pressure, along with the exiting low, will make for a tight pressure gradient, which should allow for stiff northwest winds perhaps in the 15-25mph range. Temperatures will drop back into the low 40s with the arrival the colder Canadian air.

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GFS model output for Sunday night

Monday – the storm system from Saturday will move offshore, but it appears from model runs that there’s some chance the storm lingers. As the high pressure from Sunday moves off to the northeast, the clockwise flow behind it may draw this offshore area of low pressure back into the area. This could lead to some rain on Monday. It’ll be a mostly cloudy day otherwise with highs in the low 40s.

Pacific Storm Slams California

Earlier this week, California got slammed by a very strong Pacific low. This storm brought on furious rains that dropped 1″+ in many areas of Northern California, with totals as high as 3-4″ in spots near the Coast Range and Sierra, as well as further south in the mountains east of San Diego. These totals represent more rainfall than had fallen in many of these areas all of last year.

You can see from the map below which overlays drought conditions (the deeper the red, the more extreme the drought, with the darkest red representing extreme/record-breaking drought) with rainfall totals from yesterday. You’ll see that much of the heaviest rain did fall over regions worst affected by drought. Sadly, though this is a case of too much of a good thing, as much of this desperately needed rainfall occurred so quickly, it will simply runoff back into the ocean.

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Map of California with drought condition layer (reds/oranges), and rainfall totals from yesterday

NYC Weekend Weather – Nov 20, 2014

We got a break from the arctic chill briefly today, but temperatures will fall again for Friday as a cold front currently sitting on top of us passes through. High pressure builds in Friday allowing for sunny conditions, but temperatures will still not be that warm. A big warm up is in store for the second half of the weekend and we could be hitting a rainy low-mid 60s by Monday.

Friday – following the passage of a cold front sitting over us now, skies will clear up overnight tonight and allow for excellent radiational cooling, so low temperatures will be generally in the upper 20s in the city. High pressure works its way in Friday, but with the influence of a cool west wind, the high temperature will probably still only be near 40.

Saturday – another nice day, with plenty of sun, and temperatures will be slightly warmer in the mid-40s, but the big warm up won’t occur until Sunday.

Sunday – a low pressure center with its origins over the Texas Panhandle will be moving northeast towards our area. A warm front will rotate around in front of it, allowing for the influx of a comparatively very warm and moist airmass into the area. The chance of rain will increase steadily along with cloud cover throughout the day Sunday such that by the late evening, showers will be likely. High temperatures should be in the mid-50s.

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Significant warm up ahead for the latter half of the weekend going into early next week

Monday – as the forecast map from the Weather Prediction Center below shows, the low pressure system from the map above is forecast to intensify significantly as it pulls northeast. This is a classic, mature mid-latitude cyclone with an occluded low and front (purple line extending from the center of the low), a cold front, and a warm front. The warm front will rotate through first, allowing us to get into the warm sector, where there will be plenty of energy and moisture for rain, which could occur in periods throughout Monday. High temperatures will be balmy in the mid-60s.9khwbg_conus

Thanksgiving Storm?

The chance of a significant Thanksgiving storm is decreasing, though not completely nil. Once the cold front above passes, we’ll see a return to cooler temperatures in the low 50s. It’s worth mentioning that the set up behind the cold should once again favor lake effect snow, so if you’re traveling to any of the usual snow belt areas around the Great Lakes, be prepared.

Stunning Satellite Images – Lake Effect Snow

In my previous post, I discussed the ongoing epic and record breaking lake effect snowstorm that’s absolutely pummeled areas of the Great Lakes snowbelts, with the Tug Hill Plateau area south of Buffalo the worst affected. Snowfall totals yesterday were already approaching 6 feet, and this morning, the snow continues to pile up. Check out this series of satellite images and accompanying analysis. These images are simply stunning in how clearly they demonstrate the powerful effects of lake effect snow.

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Satellite image of the Great Lakes captured by Geostationary Operational Environmental Satellite. You can clearly see bands of lake effect snow streaming across the entire region.

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Weather Prediction Center’s analysis of current surface conditions – note the low pressure center over extreme NE Ontario/SW Quebec

A close up of Lakes Erie and Ontario – luckily for these folks, winds will finally begin shifting tomorrow as that low pulls away and winds shift from ideal direction for long fetches across the lakes to the northwest.

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Epic Lake Effect Storm

As you know, I try to stick to local weather, but from time to time, a weather event occurs that you just can’t help talking about. Over the course of the last two days, areas in the snow belts around the Great Lakes have been pummeled by an epic lake effect snow event. The snow belt in the Tug Hill Plateau south of Buffalo has seen the worst of it, with snowfall totals in certain neighborhoods already approaching six feet. And it isn’t over yet!

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From Wil Fuentes on Instagram (@wilfuen) – sourced from Time.com

Based on observations from the National Weather Service data, it looks like wide swathes of the area south of Buffalo just got hammered with snowfall ranging anywhere from 36″-60″ (3-5 feet!) of snow.

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Measurements of snowfall around Buffalo – check out that 57″ number south of Elma, NY
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National Snow Analysis from National Weather Service – 35″+ observed in a period of 24 hours!

The snow is so brutal that the Buffalo Bills are scrambling to clear Ralph Wilson Stadium ahead of a scheduled game on Sunday. Lake Effect Snow Warnings are still in force in the area – and there are forecasts of an additional two feet of snow in the next couple days. The NFL may need to move or postpone the game if the Bills can’t get the snow cleared in time. The team is giving away tickets and such to anyone who’ll help dig out.

What is Lake Effect Snow?

Lake effect snow occurs when very cold air flows over a relatively warm body of water. As the cold air blows across the surface of this warmer body of water, it can quickly become saturated with moisture that evaporates (cold air can become saturated quickly because it inherently cannot hold that much water vapor). When this now saturated airmass hits the opposing shoreline, orographic (terrain) forcing causes the air to rise up (leading the airmass to become so cold that the moisture is forced to precipitate out), and provides the energy to spark of often intense, highly localized precipitation events.

This particular event has been so prodigious partially because of the alignment of winds over the surface of Lake Erie. Fetch, or the distance over which air flows across a body of water, greatly influences the severity of a lake effect storm. The longer the fetch, the more time the air has to pick up moisture off the water. In this case, the water temperature of Lake Erie is still relatively warm since air temperatures have not been that cold yet, and the winds are oriented such that the fetch is maximized over the surface of the lake (from west-southwest to east-northeast). Conditions should improve rapidly by Friday as high pressure over the Central Plains moves to the east and winds shift to the northwest.

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NYC Weather Update – Oct 14, 2014

Apologies for the lapse in posts last week. There was plenty to talk about with the formation and dissipation of Hurricane Fay, and with Hurricane Gonzalo developing. Gonzalo won’t be a threat to the U.S. mainland, but may wreak havoc in the vicinity of Bermuda as a low end Category 3 storm with 115-120mph sustained winds. This storm has the potential to hit Category 4.

Back to our region:

Today – we get to enjoy a very warm day for this time of the year with highs in the mid-upper 70s and sunny skies! Unfortunately, clouds will begin spreading over the area in a few hours time ahead of a system described in detail below.

Wednesday – there will be a chance of light rain in the morning, with the chance for more substantial rainfall increasing in the afternoon. Temperatures will remain mild in the mid-70s with persistent southeasterly flow channeling in warm, moist air from the south ahead of the cold front and storm system that was responsible for a severe weather outbreak in parts of the Midwest and Southeast earlier this week.

Thursday – will be the main event. Lucky for us, the storm system coming at us won’t be bringing severe weather, however, a thunderstorm or two is not out of the question. The main issue for us will be the risk of flooding from this slow moving system. Forecast models show training of storm cells, meaning the same areas will get hit repeatedly or continuously with moderate rain showers. Rain will likely be falling throughout the entirety of the day Thursday with little or no breaks. Rainfall totals of nearly 2″+ could lead to some minor flooding. However, the rain is welcome since we are nearly 3″ below average for rainfall. Temperatures should again remain on the warm side with highs in the mid-70s.

NAM high resolution model output for Thursday, Oct 16 @5PM
NAM high resolution model output for Thursday, Oct 16 @5PM – note the bright blue and purples stretched over the area, indicating bands of heavier rain
Precipitation total forecast for 8PM Wednesday-8PM Thursday. Nearly 2" for the NYC area.
Precipitation total forecast for 8PM Wednesday-8PM Thursday. Nearly 2″ for the NYC area.

Friday – things settle down quickly as a brief window of calm weather enters the picture. Temperatures will be cooler in the wake of the cold front with west winds and highs in the lower 70s.

NYC Weather Update – Sept 9, 2014

This week features a rather active pattern, with several chances for precipitation starting with today.

Tuesday – there is some small chance for scattered rain showers today associated with an area of low pressure that is currently located over North Carolina. However, this chance of rain will be primarily confined to areas south of the city. As the area of low pressure slowly moves offshore of the Mid-Atlantic states, the pressure gradient will strengthen, allowing for a persistent easterly wind to continue transporting cool, maritime air into the region. Temperatures will remain on the cool side, with highs similar to yesterday in the mid-70s.

Wednesday – conditions will improve somewhat as the aforementioned area of low pressure exits east over the Atlantic. We will still not be able to escape a cool, onshore wind from the northeast, so even though clouds will diminish, high temperatures will again struggle to reach 80.

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Cold front approaches on Thursday

Thursday – the most substantial chance for rain this week will arrive with the passage of a cold front late in the day Thursday into the overnight hours. Warmer air from the southwest ahead of the cold front will translate to about average high temperatures in the low 80s under cloudy skies. As the cold front nears, showers and some thunderstorms will be possible. Current timing of the forecast models suggest that the bulk of the rain will not arrive until the evening hours.

Friday – conditions will improve Friday as high pressure builds in again in the wake of the cold front passing Thursday. Temperatures will drop back into the mid-70s with cooler, Canadian air filtering in from the north behind the front.

Tropical Storm Edouard?

Tropical wave off the coast of Western Africa
Tropical wave off the coast of Western Africa

A vigorous tropical wave moved offshore of Western Africa earlier this week, and is being monitored for possibility of tropical storm formation later this week. Environmental conditions are forecast to remain favorable for development with low wind shear and warm sea surface temperatures. This storm may bring some impacts to the East Coast of the United States, but it is too early at this point to know the scope of that impact.