Tag Archives: nyc wx

NYC Weather Update – Apr 15, 2019

The same storm system that impacted the Deep South this weekend with severe weather, including several tornadoes that caused fatalities, swept through the area overnight. Some severe wind gusts were reported, and area transit networks experienced some delays due to storm-related damage. As this storm departs east, it will continue deepening, resulting in strong winds the remainder of today. Another storm system is forecast to move in to the region Thursday and going into the weekend. Temperatures during the week are expected to be mostly around normal for this time of year.

Rest of today – windy, with decreasing cloud cover. Steady west winds between 20-30 mph later in the day. This will help bring colder air into the area, with highs already peaking this morning in the low-60s then dropping back to the mid-50s by this afternoon. Overnight lows in the low-40s with partly cloudy skies.

Tuesday – sunny day, with winds calming and seasonable high temperatures in the low-60s. Overnight lows in the mid-40s and mostly cloudy.

Weather Prediction Center surface forecast for 8AM Wednesday

Wednesday – increasing clouds as a backdoor cold front works its way through. High temperatures in the low-60s. Overnight, mostly cloudy with lows in the mid-40s.

Thursday – chance of rain as a low tracks slowly from the Plains to the Great Lakes. East of this low, a slow moving warm front could touch off showers during the day and overnight Thursday. High temperatures around 60°F, overnight lows quite mild due to the influence of the approaching warm front and warm advection, in the low-50s.

GFS model output for 7AM Thursday

NYC Weather Update – Apr 9, 2019

Summer-like warmth has given way to more seasonable temperatures for this time of the year. The return to normal temperatures will be accompanied by the possibility of rain. Later in the week, temperatures will climb back up again as we are forecast to be back in the warm sector of another approaching storm. This storm should bring some rain Friday and overnight into Saturday, resulting in what should be a decent weekend

Rest of today – mostly cloudy, temperatures in the upper-50s to around 60ºF. Increasing chance for showers later this evening, around 6PM when a line of showers accompanying a cold front is expected to hit the area. Overnight lows behind this front will be much cooler than last night, in the mid-40s.

High resolution rapid refresh simulated 1-km radar for 6PM tonight

Wednesday – should be a nice day with mostly sunny skies and temperatures in the upper-50s. Overnight lows will be cool, around 40ºF.

Thursday – cool start to the day results in high temperatures around the mid-50s with mostly sunny skies and increasing clouds. Overnight lows climbing into the upper-40s.

Weather Prediction Center surface forecast for 8AM Friday. Note that we’ll be in the warm sector of this storm for a good part of the day.

Friday – warmer, with high temperatures in the mid-50s. Chances for rain increasing later in the day with a cold front forecast to be approaching from the west. Overnight lows in the low-50s.

NYC Weekend Weather – Apr 5, 2019

A cool start to the weekend should give way to a nice couple of days before another storm moves in to start next week. During this period, high temperatures will start well below normal, then rise above average before finally settling around average. Looking ahead, another storm system appears to impact the area late next week, bringing a colder weekend next week in its wake.

Rest of today – cool, cloudy with high temperatures only in the mid-40s. Increasing rain chances towards the evening and overnight hours. Rain should taper off overnight then we should see overnight lows stabilize in the low-40s as warm advection takes hold. 

Saturday – clouds diminishing as the low responsible for the rain moves over the Atlantic to our south. High temperatures in the mid-60s, maybe a touch warmer if we see clouds break earlier than forecast. Overnight lows milder in the upper-40s.

Weather Prediction surface forecast for 8AM Sunday

Sunday – high pressure stays in control and gives us a pleasant, mild day with high temperatures in the low-60s. The high pressure and nice weather doesn’t stick around long though, with another storm system approaching during the overnight hours going into Monday. Overnight lows should hold around 50ºF as rain starts to fall.

Monday – despite clouds and rain sticking around, temperatures will surge to about 70°F with a warm front forecast to pass through.

NYC (KLGA) Climatology for April

During my time taking classes as part of Penn State University’s Undergraduate Certificate in Weather Forecasting, we were taught that understanding the climatology of the location you are interested in is an important prerequisite for making accurate forecasts. This post continues on this theme, adding a climatology for April.

Other Month’s Climatologies

January
February
March
May
June
July
August
September
October
November
December

Station Basic Information

City Name / Station ID: New York, NY (LaGuardia Airport – KLGA)

Local Geography and Topography

Station Elevation: 10 feet above sea level.

Station Location: LaGuardia Airport (KLGA) is situated on the north shore of Queens along the East River, approximately 6 miles east-northeast of Midtown Manhattan.

KLGA’s location within the broader NYC area, as seen in a Google Maps terrain view

Important Topographical Features: New York City is located in the extreme southeastern corner of New York State, bordering suburban New Jersey and Connecticut. These suburban regions combined with those in Long Island comprise the Greater New York City Metropolitan Area, which is the most populous urban agglomeration in the United States and one of the populous urbanized areas in the world with an estimated population of 18 million. New York City itself sprawls across the coastal plain around the Hudson River estuary. The terminal moraine formed by glaciers of the last Ice Age result in a ridge of higher terrain that cuts a swath from southwest to northeast across the boroughs from northern Staten Island, northern Brooklyn, southwestern through central and northeastern Queens. Otherwise, the city itself is low lying. This ridge varies in height between 200-400 feet, rising sharply from south to north, but tapering more gently north. North and west of the city (about 30-50 miles away), lie significant elevations of the Catskills (north), Poconos (west), Taconics that are part of the broader Appalachian Mountain Range. The elevations of the lower foothills can range from 1000-1500 feet. Some of the elevations in the Poconos and Catskills, west and north of KLGA respectively, peak between 2000-3000 feet. The open expanse of the Atlantic Ocean lies south of KLGA and New York City. Long Island Sound also lies east-northeast. The vast urbanized area of the NYC metropolitan region has significant effects on local microclimates via differential heating (urban heat island effect). KLGA is in a low-lying area sensitive to UHI effects and marine influences.

Topographical map of New York State

Per the Local Climatological Data report from the National Weather Service:

On winter mornings, ocean temperatures which are warm relative to the land reinforce the effect of the city heat island and low temperatures are often 10-20 degrees lower in the inland suburbs than in the central city. The relatively warm water temperatures also delay the advent of winter snows. Conversely, the lag in warming of water temperatures keeps spring temperatures relatively cool. One year-round measure of the ocean influence is the small average daily variation in temperature.

National Weather Service – NYC Office

Wind Patterns

Below is a wind rose – you can read more about how to interpret this chart here.

KLGA April wind rose

Frequency (percentage) of the single most common wind direction: Due northwest occuring about 13% of the time.

Directions that are most and least common: Most common wind directions following due northwest are due south (10%), west-northwest (9%), and due northeast (8.75%). Least common wind directions are east-southeast (1.25%), due east (2.5%), and due southeast (2.75%).

Direction(s) most likely to produce the fastest winds: Winds from the northwest, west-northwest, and to some extent the northeast and east-northeast tend to produce the fastest winds.

Direction(s) least likely to produce the fastest winds: Winds from the east-southeast, due east, and south-southwest are least likely to produce the fastest winds.

Impacts of wind direction on local weather: Like March northwesterly winds during April are likely tied to the passage of cold fronts and coastal storms. Cold air advection from these winds will still be quite robust during the beginning of the month especially, as record lows for this month suggest. Winds from the northeast are still tied to backdoor cold fronts arriving from the Canadian Maritimes, bringing a moist, cool maritime polar air mass, or the advance of coastal Nor’easter type storms. During April, sea surface temperatures around NYC become markedly cooler than the air temperature as average highs continue climbing in response to more direct sun angle on longer spring days. On days approaching record warmth, in an overall environment of otherwise light winds, you could even see some sea breezes start forming along the coasts.

Maximum observed two-minute wind speed for the month: 48 knots (55 mph).

Temperature and Precipitation Averages/Records

Temperature units are in Fahrenheit and precipitation is in inches.

Worth Noting

April is the first month in the spring when record high temperatures exceed 90ºF. Record lows still routinely dip into the 20s during this month, reflecting the variability that spring can bring. The most recent record low was set in 2021, at 29ºF for 4/2. April also has the second highest single day precipitation record with 6.69″ falling on 4/15.

DateNormal HighNormal LowRecord HighRecord LowRecord Lowest MaxRecord Highest MinNormal PrecipRecord Precip
15540802742560.141.89
25640792939550.141.66
35640772539530.141.59
45741762436560.141.74
55741742538530.142.12
65741802240530.142.45
75842912230630.132.00
85842892538670.142.03
95942842640640.152.28
105943822939530.142.85
115943823242570.150.94
126043862944540.141.72
136044852536590.141.63
146044842741580.140.93
156144862840640.146.69
166145893144680.132.50
176245943245730.131.71
186245913545690.120.58
196246853540700.131.41
206346853547630.131.89
216346863340610.131.84
226347853344610.131.90
236447853644570.122.21
246447873646590.132.06
256448883648590.121.50
266548913747630.131.33
276548893845610.131.85
286649893641680.122.64
296649883649650.131.00
306649894247600.115.26
Range55-6640-4974-9422-4230-4953-730.11-0.150.58-6.69





NYC Weather Update – Apr 2, 2019

High pressure gives way to a be coastal storm that will sideswipe the area. Following this, we’ll see a brief warm up, but temperatures will cool off towards the end of the week. We have rain chances overnight into tomorrow and Friday night.

Rest of today – high temperatures around 50°F. Increasing clouds ahead of a coastal approaching from the south. Overnight, chance of rain with low temperatures around 40°F.

Weather Prediction Center surface forecast for 8AM Wednesday, depicting a coastal storm passing us to the southeast.

Wednesday – winds increasing to 15-20 mph in the afternoon. High temperatures warming into the low-60s be with clouds dissipating and winds shifting to the southwest. Overnight lows drop back into the low-40s behind the passage of a dry cold front. Winds will shift to a colder northwesterly direction. 

Thursday – cooler with partly sunny skies and high temperatures in the mid-50s. Low temperatures colder in the upper-30s. 

Friday – another low approaches from the southwest. High temperatures below average in the mid-40s, rain chances increase later in the day with the low pressure drawing closer. Rain chances continue into the overnight hours with lows in the low-40s.

NYC Weather Update – Mar 26, 2019

This week’s weather features the prominent impact of a slow moving, strong area of high pressure over the region. That translates to calm, generally sunny conditions with a warm up towards the end of the week as the high slides east and we end up in a milder southwesterly flow on its western edge. 

Rest of today – sunny but with cool northerly winds, we will remain below average with highs in the upper-40s and overnight lows in the low-30s

Wednesday – once again we have a cooling influence this time with northeast onshore winds that will keep temperatures below normal in the mid-40s with sunny conditions. Overnight lows again in the low-30s.

Weather Prediction Center surface forecast for 8PM Wednesday

Thursday – as the high pressure moves east of us, we see a shift in winds to the south. This should result in high temperatures right around average in the mid-50s. Should be comfortable spring weather for the Yankees home opener with a light wind blowing from right to left field. This is a welcome contrast from last year, when snow postponed the home opener! Overnight lows will be milder also in the mid-40s

Friday – the warm up continues with high temperatures kicking above normal in the low-60s. It appears the limiting factor for temperatures will be increasing clouds ahead of a cold front. Overnight lows in the upper-40s 

NYC Weather Update – Mar 18, 2019

Much above average warmth last Friday resulted in a spectacular light show from passing thunderstorms. In the wake of this, temperatures have dropped into a below average range, considerably cooler than this weekend. There will be a warm up later in the week though, along with some rain chances.

Rest of today – mostly sunny with high pressure in control. High temperatures in the mid-40s, overnight lows dropping into the mid-30s.

Tuesday – not too much of a difference between these two days. High pressure remains in control. High temperatures maybe a little warmer in the upper-40s, overnight lows again in the mid-30s.

Weather Prediction Center surface forecast for 8AM Wednesday

Wednesday – as high pressure shifts eastward, we should see a shift in winds to the west, allowing temperatures to warm into the low-50s. Overnight lows around 40°F.

Thursday – chance for showers with a frontal boundary moving through. High temperatures in the low-50s with mostly cloudy skies. Lows in the low-40s.

NYC Weekend Weather – Mar 15, 2019

This weekend will see a warm start but then a cool down into the below normal range going into next week. A rumble of thunder and showers will precede this cool down. Weather looks pleasant for St. Patrick’s Day festivities and the NYC Half Marathon this weekend. 

Rest of today – mostly cloudy with some breaks of sun after a warm front passes over shortly and we sit in the warm sector of the same storm that tore through the central US earlier this week. As the trailing cold front pulls through this evening, it could provide enough lift for some additional showers and possibly a couple thunderstorms. High temperatures will be above average in the low-60s, mid-60s if some sun breaks through while we’re in the warm sector. Overnight lows behind the cold front should be in the low-40s.

Weather Prediction Center surface forecast for 8PM Friday

Saturday – bright, sunny day with high pressure building behind the cold front. Temperatures cooler, around 50°F. Overnight lows much cooler in the low-30s.

Sunday – cold start to the NYC Half Marathon in the low-30s but high temperatures will end up in the mid-40s with lots of sun. Overnight lows again around the freezing mark

Monday – increasing clouds with a possibility for some precipitation but chances are too low now to call. Highs in the mid-40s and overnight lows back down in the low-30s again.  

NYC Weather Update – Mar 11, 2019

After a chilly start to March, things will take a turn towards much more seasonable weather this week. Still, temperatures will be slightly below average on several days. Precipitation chances don’t pop up until Friday when an approaching cold front should bring a warm up and then rain.

Rest of today – sunny, with a high near 50°F. Overnight lows around freezing.

Tuesday – a weak cold front passes through in the morning, but there will not be enough moisture for precipitation. High temperatures will be cooler than today, in the mid-40s with mostly sunny skies. Overnight lows will be cooler around 30°F.

Wednesday – sunny skies and a high temperature again in the mid-40s. Clouds will be on the increase overnight as a warm front approaches from the southwest. Overnight lows will be a touch warmer in the upper-30s.

Weather Prediction Center surface forecast for 8PM EDT Wednesday

Thursday – warmer but mostly cloudy with high temperatures in the mid-50s. Overnight lows expected to be in the mid-40s with the chance of rain increasing.

NYC (KLGA) Climatology for March

During my time taking classes as part of Penn State University’s Undergraduate Certificate in Weather Forecasting, we were taught that understanding the climatology of the location you are interested in is an important prerequisite for making accurate forecasts. As such, I’ve decided to post some critical components of climatology for the closest station to me, LaGuardia Airport (KLGA). Below, I’ve posted some general climate data, and also specific data for the month of March.

Other Month’s Climatologies

January
February
April
May
June
July
August
September
October
November
December

Station Basic Information

City Name / Station ID: New York, NY (LaGuardia Airport – KLGA)

Local Geography and Topography

Station Elevation: 10 feet above sea level.

Station Location: LaGuardia Airport (KLGA) is situated on the north shore of Queens along the East River, approximately 6 miles east-northeast of Midtown Manhattan.

KLGA’s location within the broader NYC area, as seen in a Google Maps terrain view

Important Topographical Features: New York City is located in the extreme southeastern corner of New York State, bordering suburban New Jersey and Connecticut. These suburban regions combined with those in Long Island comprise the Greater New York City Metropolitan Area, which is the most populous urban agglomeration in the United States and one of the populous urbanized areas in the world with an estimated population of 18 million. New York City itself sprawls across the coastal plain around the Hudson River estuary. The terminal moraine formed by glaciers of the last Ice Age result in a ridge of higher terrain that cuts a swath from southwest to northeast across the boroughs from northern Staten Island, northern Brooklyn, southwestern through central and northeastern Queens. Otherwise, the city itself is low lying. This ridge varies in height between 200-400 feet, rising sharply from south to north, but tapering more gently north. North and west of the city (about 30-50 miles away), lie significant elevations of the Catskills (north), Poconos (west), Taconics that are part of the broader Appalachian Mountain Range. The elevations of the lower foothills can range from 1000-1500 feet. Some of the elevations in the Poconos and Catskills, west and north of KLGA respectively, peak between 2000-3000 feet. The open expanse of the Atlantic Ocean lies south of KLGA and New York City. Long Island Sound also lies east-northeast. The vast urbanized area of the NYC metropolitan region has significant effects on local microclimates via differential heating (urban heat island effect). KLGA is in a low-lying area sensitive to UHI effects and marine influences.

Topographical map of New York State

Per the Local Climatological Data report from the National Weather Service:

On winter mornings, ocean temperatures which are warm relative to the land reinforce the effect of the city heat island and low temperatures are often 10-20 degrees lower in the inland suburbs than in the central city. The relatively warm water temperatures also delay the advent of winter snows. Conversely, the lag in warming of water temperatures keeps spring temperatures relatively cool. One year-round measure of the ocean influence is the small average daily variation in temperature.

National Weather Service – NYC Office

Wind Patterns

Below is a wind rose – you can read more about how to interpret this chart here.

March wind rose for KLGA, source: National Resource Conservation Service

Frequency (percentage) of the single most common wind direction: Due northwest occuring about 14% of the time.

Directions that are most and least common: Most common wind directions following due northwest are due northeast (11.75%), west-northwest (10.25%), north-northwest (8.5%). Least common wind directions are east-southeast (1%), due southeast (2%), and due east (2.25%).

Direction(s) most likely to produce the fastest winds: The most common wind directions are also the ones most likely to produce the fastest winds.

Direction(s) least likely to produce the fastest winds: Again, the least common wind directions are also least likely to produce the fastest winds.

Impacts of wind direction on local weather: Prevalent northwesterly winds during this month generally follow in the wake of cold fronts and coastal storms. These winds can lead to substantial cold air advection (transport of cold, dry continental polar air mass from interior Canada), often because of subsidence in the wake cold fronts mixing down very fast winds to the surface. These winds will downslope and warm slightly as they approach the coast though. A secondary maximum of winds from the northeast can be attributed to backdoor cold fronts arriving from the Canadian Maritimes, bringing a moist, cool maritime polar air mass, or in conjunction with the advance of coastal Nor’easter type storms. During March, sea surface temperatures in the vicinity of NYC are above freezing, but by no means warm. If a warmer air mass is in place prior to winds shifting to the northeast, cooler, more moist conditions will result. If a colder, below freezing air mass is present, northeasterly winds can exert moderating influence on temperatures. Persistent northeasterly winds can also lead to the potential for coastal flooding given the shape of local coastline.

Maximum observed two-minute wind speed for the month in knots: 40 knots (46 mph).

Temperature and Precipitation Averages/Records

Temperature units are in Fahrenheit and precipitation is in inches.

Worth Noting: Average temperatures in March rise above 50°F for the first month since November. However, March can certainly still produce cold days – many of the record lowest max temperatures are below freezing, with record lows still in the teens and single digits. It is a month indicative of spring when large temperature swings are possible.

DateNormal HighNormal LowRecord HighRecord LowRecord Lowest MaxRecord Highest MinNormal PrecipRecord Precip
1453171825530.122.23
24631671325500.112.44
34631651025490.122.26
4463169725460.111.53
5463272925480.120.72
64732641424480.122.47
74732691425490.131.90
84732741428540.121.20
94733751426490.122.18
104833781227620.121.52
114833701530490.121.40
124833691528490.121.83
134934831933530.123.15
144934751834500.121.41
154934741429480.131.61
165034771932510.131.12
175035741526540.131.39
185035751319510.142.05
195135721026530.131.38
205136821931530.141.18
215136701834530.142.00
225236761933540.133.15
235237741926560.141.44
245237741730500.141.63
255337771832500.131.55
265338722034510.141.26
275438832336540.141.20
285438832336580.132.83
295439862534590.141.90
305539792334590.132.65
315539822436590.142.10
Range45-5531-3964-867-2519-3645-620.11-0.140.72-3.15