Tag Archives: thunderstorms

NYC Weekend Weather – Sept 21, 2018

NYC, Rain, Thunderstorms, Weather Update, Weekend, , , , , , ,

Cooler weather arrives just in time for the astronomical start of autumn. Cloudy conditions have been persistent, and will continue today. A chance for rain and scattered thunderstorms tonight going into Saturday from a passing cold front. These will not be drenching rains like with the remnants of Florence. High pressure returns Saturday, and should give us a dry weekend, though we may continue to see more clouds than sun.

Rest of today – cool, and cloudy, with high temperatures in the low-70s. Chance for showers and thunderstorms overnight with a passing cold front.

Saturday – sunnier with high temperatures in the mid-70s. The autumnal equinox will take place at 9:54PM EDT.

Sunday – partly sunny with high temperatures in the low-70s.

Monday (Mid-Autumn Festival) – partly sunny with high temperatures again in the low-70s.

NYC Weather Update – Sept 17, 2018

NYC, Rain, Thunderstorms, Weather Update, , , , , , , ,

We had some great late-summer weather this past weekend with high temperatures in the low-80s and lots of sun. Most of this week will be quite nice as well, with the notable exception of Tuesday, when remnants of Florence impact the region and bring around a day of heavy rain. Fortunately, this wet weather will be short-lived, and the remainder of the week should see a return to mostly sunny conditions.

Rest of today – increasing clouds and humidity as remnants of Florence approach from the south. High temperature around 80°F.

Tuesday – periods of rain, heavy at time, with scattered thunderstorms possible. Otherwise cloudy, with high temperatures around 80°F again.

Wednesday – conditions improve as the remnants of Florence quicly move off to the east. A return to mostly sunny weather with cooler highs in the upper-70s as the back side of the cyclonic rotation of the remnants of Florence brings a cold front through.

Thursday – another mostly sunny day with high temperatures in the low-70s, high pressure building should continue to keep things dry for the region.

NYC Weather + Special Tropical Update – Sept 10, 2018

Cool Images, NYC, Rain, Storms, Thunderstorms, Tropical/Hurricanes, Weather Update, , , , , , , , , , , , , , , , ,

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 Weather Update – Sep 4, 2018

NYC, Rain, Storms, Thunderstorms, Tropical/Hurricanes, Weather Update, Weekend, , , , , , , , , , , , ,

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 – Aug 27, 2018

NYC, Thunderstorms, Weather Update, , , , , , , , ,

The dog days of summer arrive in full force this week before we close out the month of August. With a strong Bermuda high in place well southeast and secondary high pressure in the area, we will see a heat wave take place from today into Thursday. Several days of hot, humid weather are on tap until a cold front moves through Thursday, bringing the potential for strong thunderstorms and much cooler air in its wake.

Rest of today – hot, though not quite as humid as it will be later this week. High temperatures in the low-90s with mostly sunny skies expected.

Tuesday – even hotter, and more humid than today with high temperatures in the mid-90s with sunny skies.

Wednesday – yet another hot, oppressively humid day with high temperatures in the mid-90s. Both Tuesday and Wednesday should see heat index values above 100°F due to high dew point values as well.

Thursday – a cold front is forecast to push through the area Thursday. Along and ahead of this front, we are expecting the chance for some scattered strong to severe thunderstorms given the ample moisture available and hot temperatures. Temperatures will still be hot, in the low-90s, before this frontal boundary passes through. Behind this cold front, temperatures will be 10-15°F cooler Friday into the weekend.

 

NYC Weekend Weather – Aug 10, 2018

Flooding, NYC, Rain, Thunderstorms, Weather Update, Weekend, , , , , , , , , ,

Enjoy the pleasant weather today if you can, because conditions will deteriorate going into the weekend. Wet weather will impact the NYC region starting tonight, lingering well into early next week. Rain could be heavy at times, and flash flooding is a possibility. Temperatures during this time will be considerably cooler than this past week with the influence of clouds and rain. We will be stuck under the influence of multiple shortwaves moving through at the upper level during this time. Starting next week, forecast models suggest that a closed 500 mb low will form, then linger in the area due to strong downstream ridging (high pressure) over the western North Atlantic. This cut-off upper level low will provide for persistent unstable conditions conducive for multiple rounds of rain and thunderstorms. I will be off the next two weeks on vacation and will not be posting updates unless there’s severe weather forecast for the area.

Rest of today – increasing clouds as a cold front approaches the area from the northwest but stalls out and dissipates overnight. High temperatures in the upper-80s. Chances for showers and thunderstorms increase overnight.

Saturday – multiple chances for showers and thunderstorms, starting early in the day, then again in the afternoon and evening hours. Much cooler with mostly cloudy skies and high temperatures only in the mid-70s. The cold front that passed through yesterday will return north as a warm front. Ahead of this, winds will be easterly and onshore, bringing the cool, damp influence of the Atlantic over the area.

Sunday – warmer with high temperatures in the low-80s but still mostly cloudy. Chances for rain throughout the day as the frontal boundary above remains in the area.

Monday – yet another impulse of shortwave energy aloft brings a surface low towards the area, so rain chances persist with a shot for thunderstorms as well. Mostly cloudy with highs in the low-80s.

NYC Weather Update – Aug 6, 2018

NYC, Rain, Storms, Thunderstorms, Weather Update, , , , , , , ,

This week starts off with a heat wave, with high temperatures expected to top 90°F up through Wednesday. A chance or showers and thunderstorms Wednesday will not bring too much in the way of relief from the heat and humidity. The air mass behind the cold front moving in Wednesday is only slightly cooler and less humid than the one in place now.

Rest of today – hot, humid, with high temperatures in the low-mid 90s.

Tuesday – more of the same, hot, humid weather with highs in the low-90s. A chance exists for some scattered showers and thunderstorms late in the day.

Wednesday – more organized showers and thunderstorms are expected to pass though late in the day Wednesday and overnight into Thursday as a cold front approaches from the west. High temperatures ahead of the front are expected to be in the low-90s again.

Thursday – a chance for leftover a shower or thunderstorm exists early, then improving conditions with high temperatures in the upper-80s and mostly sunny skies.

Friday – looking sunny now, with highs in the upper-80s.

NYC Weekend Weather, a Tornado in Queens? – Aug 3, 2018

NYC, Rain, Severe Weather, Thunderstorms, Tornadoes, Weather Update, Weekend, , , , , , , , , , , ,

A wet start to the weekend will then give way to much warmer weather. We’ll get a break from the rain Sunday and Monday before the next shot for rain. Of note, a possible tornado may have impacted parts of northern Queens last night.

Rest of today – increasing chances for showers and thunderstorms especially in the early afternoon. Otherwise, mostly cloudy with high temperatures in the mid-80s.

Saturday – more widespread showers and thunderstorms in the morning, with some concern for flash flooding. The set up also could produce some isolated severe weather as a weak impulse of energy travels up the upper trough that’s been locked in over the Eastern US this week. Improving conditions later with highs in the mid-80s.

Sunday – the upper trough that’s been causing this week’s wet weather finally exits east. High pressure begins to build south of us, bringing warmer temperatures with highs in the low-90s and lots of sun.

Monday – more of the same as Sunday, sunny, hot and humid with highs in the low-90s.

Possible Tornado in Northern Queens Last Night

At 10:18 last night, residents in northern Queens, the eastern Bronx and northern Nassau received alerts from our local National Weather Service forecast office of a tornado warning. The damage was evident this morning, with many downed trees in College Point. A team from the NWS is assessing the damage to determine whether what hit this area last night was really a tornado, or if it was some other non-tornadic wind phenomena.

I was in a neighborhood that received this warning, but at first, I almost thought it was in error because there were no signs outside of anything awry, no thunder, no rain. However, a quick look at the base radial velocity imagery on the JFK high-definition terminal Doppler radar was revealing – there certainly was a storm with very strong rotation, hence why the warning notes “radar indicated tornado”. In the annotated base radial velocity image below, the white circle indicates a tight mesocyclonic circulation.

Without going too much into technical detail, the greens indicate inbound velocities relative to the radar station (air was flowing towards the radar), while oranges and reds indicate outbound velocities (where air was flowing away from the radar). When forecasters see a “velocity couplet” like this where inbound and outbound velocities are close together, they know this is a signature of strong storm rotation within a mesocyclone. If, within this couplet, you get a “gate to gate” (i.e. adjacent pixels) where the difference between inbound and outbound velocities exceed 90 knots, this is referred to as a “tornado vortex signature”. In this image, if you do the math, you get that the max difference between inbound and outbound velocities was 86 knots, and you an see what appears to be a tornado vortex signature.

We’ll see what the NWS’ assessment says later today, but it appears to me that there was a tornado at some point over northern Queens last night!

UPDATE (1:46PM August 3, 2018): The National Weather Service issued a report confirming that an EF0 tornado touched down in portions of College Point, Queens last night.

NYC Weather Update – Jul 30, 2018

Flooding, NYC, Rain, Thunderstorms, Weather Update, , , , , , , ,

Yesterday and today have been a welcome relief from the recent spell of tropical humidity. However, the comfortable weather won’t last this week. A warm front will sweep through and bring us right back into an unsettled, tropical weather pattern. There will be chances for showers and thunderstorms every day this week. Humidity will be back on just as last week.

Rest of today – cloudy, with high temperatures topping out in the low-80s then dropping to the mid-70s by end of the day.

Tuesday – as a warm front nears from the south, there will be chances for showers and thunderstorms throughout the day. High temperatures will be capped in the low-80s due to southeasterly onshore flow off the Atlantic ahead of the warm front.

Wednesday – temperatures should be in the mid-upper 80s, depending on the timing of the warm front passing through. Chances for showers and thunderstorms yet again. Heavy downpours from slow moving storms could cause localized flooding. Dew points will increase into the low-70s resulting in an uncomfortably muggy day.

Thursday – behind the warm front, we’ll get into even warmer and more humid air due to the presence of a Bermuda High. A prefrontal trough associated with a cold front will approach the area and once again give us a chance for thunderstorms. High temperatures should be in the upper-80s.

 

NYC Weekend Weather – Jul 27, 2018

NYC, Rain, Thunderstorms, Weather Update, Weekend, , , , , , , , , , ,

Thunderstorms roll through later this afternoon and into the overnight hours. The cold front bringing these storms stalls out before finally pushing through Sunday. A welcome break from this muggy weather follows, with dew points finally dropping out of the upper-60s into more comfortable ranges. The break is short lived, as the cold front will return mid-week next week as a warm front, bringing another round of warm and humid weather with chances for rain.

Rest of today – hot and humid today with high temperatures approaching 90°F and plenty of moisture still lingering. Late in the day, clouds will increase as a cold front approaches from the west. Thunderstorms are expected to develop along a pre-frontal trough. Atmospheric dynamics favor some possibility for storms to develop damaging wind gusts. There will be modest instability with little convective inhibition by later in the day with plenty of solar heating and humidity in place. Wind shear, though weak in the lower layers of the atmosphere, increases substantially aloft, and so storms do have a chance to become strong. Any storm could bring about heavy rain and isolated minor flash flooding. The best timing of the onset of the rain appears to be between 7-9PM as of recent High Resolution Rapid Refresh model runs. The Storm Prediction Center has placed the western part of the region (including parts of NYC) under a slight risk of severe weather. By the time the storms hit the city, given the current timing, they should be weakening due to day time heating ceasing.

Saturday – only slightly cooler with high temperatures in the mid-80s. Still quite muggy. Spot showers are possible due to the cold front lingering in the area.

Sunday – finally, we get a refreshing day off from the humidity with dew points dropping into the low-60s and high temperatures in the mid-80s with lots of sun. The cold front finally pushes through with high pressure behind it bringing cooler, drier Canadian air our way.

Monday – should be another comfortable day with high temperatures in the mid-80s and relatively less humid conditions.