Category Archives: Thunderstorms

NYC Weather Update – May 11, 2015

Cool Images, NYC, Rain, Thunderstorms, Weather Update, , , , , , , , , , ,

This week will be a tale of two airmasses, starting with a warm, moist, maritime tropical one, and transitioning to a more seasonable, cool, dry, continental polar airmass (don’t be alarmed, polar refers to the origin of this airmass, not necessarily the temperatures, although some light frost might occur later this week far inland). In terms of sensible weather, you will notice a marked change between warm, humid, summer-like weather Monday and Tuesday, and cool, windy, and crisp spring-like conditions to end the week.

Rest of today – basically a repeat of Sunday, high temperatures topping out in the low-80s. There is a very slight chance of showers and thunderstorms over the inland areas west of NYC where some instability might develop from daytime heating. South-facing shores will be noticeably cooler and cloudier due to an onshore wind from the south off the ocean.

Tuesday – some fog and clouds early, then mostly cloudy with a chance for rain and thunderstorms in the afternoon ahead of an approaching cold front. High temperatures remain much above normal in the low-mid 80s.

Wednesday – the aforementioned cold front makes its passage, and brings in its wake a return to more seasonable weather. Average temperatures for this time of year are only around 65ºF, and that’s just about where we will end up on Wednesday under mostly sunny skies. There will be a noticeable wind from the northwest as well, making it feel extra crisp.noaad3

Thursday – sunny and dry, with a slight rebound in temperatures into the upper-60s.

NYC Weekend Weather – May 8, 2015

NYC, Outside of NYC, Thunderstorms, Tropical/Hurricanes, Weather Update, Weekend, , , , , , , , ,

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 Weekend Weather – Apr 30, 2015

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

This week ends with clouds and some small chance of rain, but we’re in for a real sweet stretch of pleasant conditions and warmer than average temperatures from Sunday into early next week. In fact, we could be hitting 80 by Tuesday ahead of a cold front that could bring some thunderstorms with it, before we cool back down into the low-70s, which is still above normal.

Friday – due to the influence of a weak area of low pressure to our south, we will be seeing generally cloudy skies, with some very slight chance for scattered showers in the southernmost portions of the region. Temperatures will be moderate by northeast winds circulating counterclockwise around the low pressure to our south, yielding high temperatures in the upper 50s to near 60, just a few degrees below normal.

Saturday – as the aforementioned low pressure system slides off to the east over the Atlantic, clouds should gradually decrease. Temperatures will also rebound somewhat to around normal with a high in the mid-60s. However, there could be just enough instability in the atmosphere to spark a couple scattered showers or thunderstorms.

 

gfs_namer_081_1000_850_thickSunday – by this time, an area of high pressure will have developed over the Carolinas. This setup will favor the influx of a warm airmass from the Gulf of Mexico. Skies will clear, and temperatures will be noticeably warmer in the low 70s.

Monday – another gorgeous day to start the week, with sunny skies and high temperatures in the mid-70s (10º above normal). Don’t say I told you so, but if there were a day to skip work, this would be it.

Climate Prediction Center's 6-10 forecast for temperature. Our odds are very good for getting warmer than normal temperatures.
Climate Prediction Center’s 6-10 forecast for temperature. Our odds are very good for getting warmer than normal temperatures.

Tuesday – although it will be even warmer Tuesday than it will be Monday, with highs possibly topping 80, it won’t be quite as pleasant since clouds will be building up ahead of a cold front that will bring our next chance at rain.

NYC Christmas Weather Update – Dec 24, 2014

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

A foggy start to the busy travel day for many will feature periods of locally heavy rain and gusty winds later this morning into the early afternoon. Near record warmth with high temperatures in the low 60s today will give way to cooler but calmer weather going into the holiday weekend before another round of unsettled weather early-mid next week.

Today – foggy conditions will be a prelude to a stormy Christmas Eve. An approaching warm front will move through shortly and allow for a surge of warm air to raise temperatures into the low 60s. Along with this, there looks to be a period of widespread showers in the late morning and early afternoon hours. Afterwards, there should be a lull in the rain before a second round of showers and possibly scattered thunderstorms associated with this storm system’s trailing cold front moves in. Winds will pick up ahead of and then behind this cold front. If you are traveling either by air or car, the latter part of the day could see some weather related disruptions and delays. Overnight lows will be very mild near 50.

Plenty of fog on the Whitestone Bridge
Plenty of fog on the Whitestone Bridge
NAM model stimulated radar image for 2PM EST, 12/24/2014
NAM model stimulated radar image for 2PM EST, 12/24/2014

Christmas Day – conditions improve dramatically during the day in the wake of the cold front. Any lingering showers should end early in the morning with rapidly clearing skies accompanied by a gusty west wind. High temperatures in the mid-50s will actually be set early in the morning with temperatures dropping steadily during the day to the upper 40s later in the afternoon.

Friday – fair weather continues as an area of high pressure builds over the Eastern US. Partly cloudy with a mild high near 50.

Saturday – much the same as Friday with high pressure still in control. High again near 50.

Sunday – mostly cloudy with a chance of rain, slightly cooler with highs in the mid-40s. A frontal boundary may stall just south of us, setting up conditions for an extended period of unsettled weather next week.

NYC Weather Update – Oct 20, 2014

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

This week will be a colder repeat of last week, with a wet mid-week period, but better conditions going into the weekend.

Tuesday – an area of low pressure with an accompanying cold front moving in from the Great Lakes will give us a chance of showers, especially in the afternoon Tuesday. Ahead of the front, temperatures will warm up to the mid-upper 60s under mostly cloudy skies.

Wednesday – the low pressure above will spawn a secondary low off the coast of the Mid-Atlantic. This low pressure center will be the main weather-maker for the mid-week period. Forecast models point to a stubborn storm system that will meander slowly off the Northeast. Multiple bands of rain will rotate around this low. There will be enough instability with the vorticity associated with the low to allow for the possibility of thunderstorms, despite the fact that this low will be a colder core low. Temperatures will only be in the upper 50s with a unpleasant north to northeast wind.

gfs_namer_054_1000_850_thick
GFS model output for Wednesday, Oct 22, 2014 @ 8PM EDT
gfs_namer_069_500_vort_ht
GFS 500mb vorticity and height – notice the concentric circles indicating a closed low off the coast of the Northeast and New Engalnd. The darker yellows indicate areas of increased vorticity and energy.

Thursday – the rain should subside by around noon Thursday, but before all is said and done, we could get another  1-1.5″ of rain. The rainfall will mainly be concentrated to the east of the Hudson River, including NYC and Long Island. Temperatures will remain cool in the mid-50s with winds diminishing from the north and northwest.

Friday – the low will lift away, it will dry out, and clouds will diminish as temperatures also rebound back into the lower 60s to end the week.

NYC Weather Update – Oct 14, 2014

Flooding, NYC, Outside of NYC, Rain, Severe Weather, Storms, Thunderstorms, Tropical/Hurricanes, Weather Update, , , , , , , , , , , ,

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 Weekend Weather – Oct 2, 2014

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

Friday and Sunday will be the sunny and pleasant bookends to what will be a stormy and rainy Saturday this weekend.

Today – we’re looking at sunny skies and high temperatures in the low 70s. Clouds will begin to build back in later in the evening as the storm maker for Saturday begins to move in from the west.

Screen Shot 2014-10-03 at 8.00.54 AM
NAM high resolution model output for Saturday at 10AM EDT
Screen Shot 2014-10-03 at 8.01.47 AM
Weather Prediction Center forecast map for Saturday

Saturday – a negatively tilted frontal system will be moving over the area Saturday, with the worst of the rain coming between about 10AM-3PM. We will be in the vicinity of a triple point (junction between a cold, stationary, and occluded front, this feature is common with mature mid-latitude cyclonic systems) that will be draping south from a strengthening low pressure center that will be moving northeast into Ontario during this timeframe. A thunderstorm is not out of the question given the atmospheric dynamics. Temperatures should hover around the 70 degree mark despite the cloud cover and rain because of the potential for us to briefly enter a warm sector between the stationary front and cold front.

Sunday – we get a crisp blast of autumn air behind the frontal system passing through Saturday. Sunshine returns just in time for the annual BikeMS NYC, which yours truly will be participating in. Cool temperatures will be only in the mid-upper 60s.

Monday – good weather sticks around for the start of the work week with high temperatures around 70.

Our next chance for precipitation should come Tuesday-Wednesday. The low pressure center responsible for the rain Saturday is forecast to close off and retrograde (move west instead of east, with prevailing upper level winds) over central Canada. An impulse of energy will rotate around this center and lead to another cold front passing through our area.

 

NYC Weather Update – Sept 9, 2014

NYC, Outside of NYC, Rain, Thunderstorms, Tropical/Hurricanes, Weather Update, , , , , , , , , , , , ,

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.

Screen Shot 2014-09-09 at 8.50.45 AM
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.

 

NYC Weekend Weather Update – Sept 4, 2014

NYC, Storms, Thunderstorms, Weather Update, Weekend, , , , , , , ,

We’re still in the grips of a warm and humid airmass, despite some cooling off last night due to the passage of a weak cold front. This warm trend will not break until a stronger cold front passes through the region on Saturday.

Friday – expect high temperatures once again in the mid-upper 80s, albeit with increasing cloud cover as stratus cloud decks start to filter in ahead of the aforementioned cold front.

GFS model output for 2PM EDT Saturday
GFS model output for 2PM EDT Saturday

Saturday – unfortunately, the timing of the cold front above does mean it will bring adverse impacts to our weekend plans. Showers and thunderstorms are likely to precede and accompany this frontal passage, particularly later in the day Saturday into Saturday evening. High temperatures ahead of the front will remain warm in the mid-80s, somewhat cooler near the shore. There will be a noticeable cooling with this round of storms.

Sunday – Clouds will diminish through the course of the day Sunday as a much cooler regime works its way into the area. High temperatures will only be in the upper 70s for Sunday and the beginning of the weak.

Monday – Skies will be mostly clear, and temperatures will be much cooler in comparison to Labor Day, with highs only in the upper 70s (~10 degrees cooler than Labor Day). High pressure building over us will lead to an onshore wind flow, bringing in a cool, maritime polar airmass.

Cool onshore flow due to high pressure Monday
Cool onshore flow due to high pressure Monday

 

NYC Weather Update – Sept 2, 2014

NYC, Rain, Thunderstorms, Weather Update

Despite the unofficial end of summer, today may very well turn out to be one of the hottest days of the summer! We’re looking at forecast high temperatures in the upper 80s into the lower 90s across urban areas. Some relief will be possible with afternoon thunderstorms, and then another round of showers and thunderstorms overnight. A few of these storms could be approach severe limits, however, despite the heat and humidity, atmospheric dynamics are not favorable for widespread severe weather.

Cold front passing through overnight could give some temporary relief to the heat
Cold front passing through overnight could give some temporary relief to the heat

Wednesday – despite the passage of the cold front above, temperatures will remain warm and humid with highs in the mid-upper 80s under sunny skies.

Thursday & Friday – essentially the same, hot, humid, sunny with highs in the mid-upper 80s. The culprit will be an area of high pressure that moves offshore and to the southeast Thursday. This setup will allow for hot, humid air from the Southeast of the country to pump into the area.

High pressure southeast of us allowing for hot, steamy air to enter the area.
High pressure southeast of us allowing for hot, steamy air to enter the area.

The Weekend – we’ll finally see the heat break later Saturday and into Sunday as a stronger cold front brings in a cooler, drier Canadian airmass.