Monthly Archives: October 2014

NYC Weekend Weather – Oct 30, 2014

Uncategorized

The picture for this weekend is set: a cold, wet, windy Saturday, and an even colder, even windier (though dry) Sunday. For today and Friday, we’ll get decent conditions with temperatures about normal for this time of year.

Thursday – temperatures will hit the upper 50s-around 60 under sunny skies. Enjoy it while you can!

Friday – clouds start to spread over the area and it gets a bit cooler with highs in the mid-upper 50s.

Saturday – a complex interaction between two low pressure systems will make for a tricky forecast Saturday. What is clear is that a cold, arctic airmass will be filtering in from the north. Luckily, it does appear the coldest of the air will arrive after the main portion of the storm exits to the northeast. Also, the track of the storm system will be further out past the 40N 70W benchmark, meaning the worst of the impacts will remain offshore.

This means that there most likely will not be snow, and that the western interior portions of the region will probably not see any significant precipitation. Winds, on the other hand, will strengthen from the north, ushering in a very cold airmass for this time of year. Closer to the coast, we should see rain on what will be a raw, wet, windy, winter-like day. Temperatures will only hit the upper 40s.

Sunday – for the NYC Marathon, it should be a dry, but downright chilly start with overnight lows Saturday hovering in the upper 30s. Combine that with northerly wind gusts of 25-35mph, and we’re looking at wind chills near freezing. Temperatures will not rebound that much during the course of the race, either, as high temperatures are only expected to hit the upper 40s. It’ll be important for runners to warm up properly before getting underway. They will be running with the wind directly in their face for a majority of the race, too.

gfs_namer_075_1000_850_thick

Forecast wind gusts for Sunday @ 8AM
Forecast wind gusts for Sunday @ 8AM

Next week, this arctic airmass will depart, we’ll rebound back towards normal temperatures for this time of the year.

High pressure back in control for the first half of next week, allowing for temperatures to rebound back to normal
High pressure back in control for the first half of next week, allowing for temperatures to rebound back to normal

NYC Weather Update – Oct 28, 2014

NYC, Rain, Snow, Weather Update, , , , , , , ,

Summary

This week will be archetypical of autumn weather, with large temperature swings in store for the region. We’ll start off with highs more characteristic of late summer near 70, though with clouds overhead, we may not top that number. A weak cold front will push through tomorrow with some chance of showers. Behind this front, temperatures will drop to more seasonable highs around 60 with dry conditions. The week ends like winter with an arctic airmass invading the region, leading to the possibility of snow and high temperatures only in the upper 40s.

Wednesday – clouds build in and showers will be possible for most of the day. Most rain should conclude by the evening hours. High temperatures will remain warm ahead of the passage of the cold front with winds from west pushing warm air ahead of the front.

Weak cold front passing through Wednesday, scattered showers possible.
Weak cold front passing through Wednesday, scattered showers possible.

Thursday – clear and sunny skies behind the cold front passing Wednesday, high temperatures cooler near 60. Overnight lows will be quite cool in the lower 40s with good conditions for radiational cooling.

Friday – clouds will increase ahead of the next storm system, and high temperatures will remain near 60.

Saturday – an intrusion of arctic air accompanying a strong, deep trough (cold front) will set the stage for what should be a raw, chilly, winter-like day. With the arctic air pumping in, high temperatures will struggle to even hit 50. In the chart below, you’ll see a height of 540 near us. Without going into too much detail, low heights generally correspond to colder temperatures, as colder air is more dense, it takes up less volume than the same mass of warmer air. A height of 540 is considered by forecasters to be important when determining precipitation type, as it indicates temperatures cold enough to support snow. That’s right – we will probably see some snow north and west of the city, and depending on the track of a secondary low that forms Saturday along the coast, we could even get some of the white stuff in NYC. This is a complex system, so it will bear watching over the next couple days.

 

gfs_namer_099_500_vort_ht

 

NYC Weekend Weather – Oct 24, 2014

Noreaster, NYC, Storms, Weather Update, Weekend, , , , , , , ,

We are still feeling the impacts of that Nor’easter that passed through Wednesday and Thursday. There will be some lingering showers east of NYC this morning, before gradual things begin to dry out and skies gradually clear from west to east. High temperatures will be in the mid-60s, but with a north wind blowing, it will still feel quite cool. We’ve got an excellent, fall weekend on tap.

Saturday – we’ll get sunny skies again, and high temperatures will remain in the mid-60s.

Sunday – much the same as Saturday.

Monday – high pressure will continue to build to our south. This will mean a shift in winds to the south and southwest, which will open the door for warmer air to stream in from the south. High temperatures in the mid-upper 60s, under sunny skies.

gfs_namer_093_1000_850_thickTuesday – as that high pressure strengthens, we’ll get another day of even warmer temperatures Tuesday with highs near 70. We’ll be watching for another storm system approaching from the west that could bring us a chance of rain Wednesday.

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 Weekend Weather – Oct 18, 2014

Climate, Noreaster, NYC, Rain, Weather Update, Weekend, , , , , , , , ,

We get one last day of late summer-like temperatures today before autumn comes back with a vengeance. A cold front has already passed through the city and you can already notice the winds beginning to shift to the northwest. This will herald a much cooler temperature trend. For the remainder of today, we can expect temperatures near 70 with some clouds building behind the front. There could be a sprinkle or two but nothing serious.

Sunday forecast map
Sunday forecast map

Sunday will be noticeably more cold with high temperatures struggling to hit the mid-50s and with a gusty northwest wind. Gusts could top 30mph at times with sustained winds 15-25mph. Overnight lows into Sunday and Sunday night will be downright chilly in the 40s. Some interior areas could see frost Sunday night.

Monday the winds will abate as the pressure gradient between the departing cold front and high pressure to the west eases. Temperatures will remain cool at only around 60.

Tuesday and into later this week we will see the impact of a frontal system that moves through from the Great Lakes and develops as a coastal low off the Mid-Atlantic. Current models seem to suggest that this low will linger for a few days offshore, so we could see multiple rounds of rain as bands rotate around the storm center.

gfs_namer_078_1000_850_thick

 

Winter Climate Outlook

The Climate Prediction Center has released its 3 month temperature and precipitation long range outlooks for the months ahead. As you will see, CPC has the NYC area in a zone of 33% chance of seeing a wetter and warmer than average winter. Call it a hunch, but I still think we’ll get a couple nasty Nor’easter type blizzards. Warmer than average of course doesn’t imply we won’t get freezing temperatures. A slightly warmer atmosphere would allow for more moisture and energy for coastal storms to feed off.

temp precip

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.