Category Archives: Climate

NYC Weekend Weather – Apr 30, 2015

April 30, 2015Climate, NYC, Rain, Thunderstorms, Weather Update, Weekendclimate, cold front, high pressure, low pressure, new york city weather, nyc weather, nyc weekend weather, nyc wx, thunderstorms, weather, weekend weatherLei Zhao

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.

Sunday – 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 Weather Update – Apr 7, 2015

April 7, 2015Climate, Rain, Storms, Weather Update, Weekendclimate prediction center, cold, cold front, new york city weather, nyc weather, nyc wx, rain, stationary front, warm front, weatherLei Zhao

This will be my last post for another few weeks as I will be traveling in South America. This week, we have an active weather pattern that will lead to a series of periods of rain. Mid-week, temperatures will be well below normal (mid-40s), but towards the end of the week, through the weekend, and to begin next week, temperatures will rebound to slightly above normal (low 60s).

Today – we’ve already had a round of light to moderate rain pass through earlier this morning. The rest of the day will feature temperatures falling through the 50s, along with overcast skies and a light onshore flow. A second round of rain looks set to hit the area around the evening rush hour today.

High Resolution Rapid Refresh model output for 5PM today.

Wednesday – a raw, rainy, and cold day is in store tomorrow. A stationary front (the reason for the extended period of unsettled weather) will push through late Tuesday as a cold front. This will allow for much colder air from Canada to enter the area, which will lead to temperatures only in the mid-40s (10-15º below normal). Periods of rain are likely throughout the day and into the night.Thursday – essentially a repeat of Wednesday, with chances for rain through out the day, and cold, cloudy conditions otherwise. High temperatures again only in the mid-40s.

Friday – chances for rain continue through Friday as a warm front will be approaching from the south. Once this front pushes through, we’ll see a return to milder temperatures with highs in the low 60s (about 5-8º above normal).

The Weekend – conditions finally begin to improve on Saturday with a cold front having pushed through. Chance for precipitation dwindles, with highs in the low 60s. Sunday is even better with clear skies and warm temperatures near 60.

Warm Trend for Next Week

Climate Prediction Center has our region in an area of greater than 50% chance of above average temperatures for next week. This should translate to pleasant, spring like conditions for next week!

NYC Weather Update – Mar 22, 2015

March 22, 2015Climate, NYC, Rain, Weather Updateclimate prediction center, cold front, new york city weather, nyc weather, nyc wx, spring, spring weather, warm front, warm sector, weather, winter, winter weatherLei Zhao

This upcoming week will feature some big swings in temperature, with high temperatures increasing steadily up through Thursday, when highs could 60 before a cold front swings through. Following the passage of this cold front, we dip back into the mid-40s and continue cooling into the lower-40s this weekend. The temperature trend in the medium term remains below normal, potentially well below normal even through the first week of April, as a series of cold fronts continue to allow cold Canadian air to enter the area.

Monday – an area of high pressure will yield a sparkling sunny day, but will also permit cold, Arctic air back into the region. Northwest winds combined with noticeably cold overnight lows will produce uncomfortably cold conditions. High temperatures Monday may barely break freezing. It’ll be one of the coldest day we’ve had this month.

Tuesday – also gets off to a chilly start, but high temperatures are expected to push up to around 40 (which is more than 10ºF colder than normal).

Wednesday – a clear start, but clouds will be building ahead of a warm front that will pass over the region late Wednesday. Temperatures will steadily climb to near 50, especially after the warm front passes. There will be a slight chance for rain later Wednesday in conjunction with this frontal passage.

Thursday – highs will near if not break 60, however, it is anticipated to be a overcast day with periods of rain possible throughout the day. After the warm front passes Wednesday, we’ll be firmly within the warm sector, between the warm front to our east and the approaching cold front from the west. This setup favors the influx of warm, moist air from the Gulf riding in on persistent southwesterly winds, before a dramatic shift following the cold front passing, with winds becoming west-northwest and a drop in temperatures.

Friday – high temperatures drop back in to the mid-40s, as clouds break apart and colder, dry air takes hold behind the cold front.

Below Normal Start to April

It’s close to a sure bet (70% probability) that we’ll end the month of March and start April with below normal temperatures, taking a look at the Climate Prediction Centers forecasts below. I know we’re all sick of this seemingly endless winter, but we’re still not out of the woods in terms of temperatures.

6-10 temperature outlook from the Climate Prediction Center

8-14 temperature outlook from the Climate Prediction Center

NYC Weather Update – Mar 18, 2015

March 18, 2015Climate, NYC, Snow, Weather Update, Weekendmarch, march snow, new york city weather, nyc weather, nyc wx, snow, spring, weather, winter, winter weatherLei Zhao

Just when we thought winter was on its last legs, and spring was on its way. Unfortunately, as the Climate Prediction Center forecast a couple weeks ago, a cool down is in the cards to end the month of March. In fact, it will get so cold that snow could accumulate Friday into Friday night. After a brief warmup, another shot of colder than normal air will return to grip the area to end off the month.

Thursday – a below normal, but dry day with plenty of sun and high near 40.

Friday – (ironically, first day of astronomical spring) a coastal low moving offshore of the Carolinas will then track north. Enough cold air will be in place Friday, along with a persistent northerly flow with counterclockwise circulation around the low pressure center that snow is looking likely during the course of the day. Current forecast snow accumulations are on the light side, no more than 3-4″. If temperatures are even a few degrees warmer than currently forecast, we could get away with little accumulation.

Saturday – things clear up quickly on Saturday with high temperatures back near normal in the mid-upper 40s.

Sunday – a dry cold front moves through Sunday, leading to a drop in temperatures to below normal in the upper 30s.

Cool Off Coming Up

The climate prediction center continues to point to cooler than normal temperatures for the last two weeks of March. One can only hope that the temperatures are not so cold as to allow for more snow, but I wouldn’t rule this possibility entirely out given some of the longer term forecast models.

NYC Weather Update – Mar 10, 2015

March 10, 2015Climate, NYC, Rain, Storms, Weather Updateclimate, climate prediction center, mixed precipitation, new york city weather, nyc weather, nyc wx, rain, weatherLei Zhao

We’ve finally had a stretch of warmer than average weather after what seemed like an endless winter. Things are set to get even warmer tomorrow in the wake of tonight’s rain storm, before cooling off back into normal range to end the week. Another round of rain (with some mixed precipitation inland) will be impacting the area Friday into Saturday.

Rest of today – light rain falling now should increase in intensity over the course of the evening. Steady rain is expected overnight. Dense fog and low visibilities may be a problem overnight into the early morning hours, due to the influence of a saturated, warm airmass approaching an area of colder air. Overnight lows in the low 40s, with dew points around the same (fog often forms when dew point = air temperature).

Wednesday – any remaining rain should end quickly tomorrow morning. Clouds will give way to sun as high pressure begins to take hold over the area. Before too cold air gets into the area due to a northwest wind, we should see temperatures reach the mid-50s (wouldn’t be surprised if some spots hit close to 60 with the increasing daylight hours).

Thursday – another pleasant, and seasonable day, with plenty of sun and high temperatures around normal in the mid-upper 40s.

Friday – one more day of decent weather, but with slightly more clouds than Thursday. Temperatures should top out around the mid-40s again. The next storm system approaches from the west and rain should begin to fall during the late evening hours. Overnight, some mixing with snow/wintry mix could occur, however, by daybreak Saturday, temperatures will be well above freezing and any mixing should return to all rain.

Saturday – a rainy day, but on the mild side with temperatures near 50.

A cooldown coming
Unfortunately, after a week of normal temperatures, we are likely to see a return to below normal temperatures for the second half of March, based on the following forecasts from the Climate Prediction Center. High pressure will be dropping down from Canada again next week, leading to this greater than 60% probability of below normal temperatures. Luckily, since normal temperatures are now in the upper 40s, the below normal temperatures will not mean a return to the frigid tundra.

Climate Prediction Center 8-14 day temperature outlook

Climate Prediction Center 1 month temperature outlook for March

NYC Weather Update – Mar 5, 2015

March 5, 2015Climate, NYC, Snow, Weather Update, Weekendclimate, cold, high pressure, nyc weather, nyc wx, snow, spring, weatherLei Zhao

Today may be the last major winter storm of the winter for us. It certainly has been an eventful and cold winter for the books. We’ll end the week and start off this weekend and early next week with below normal temperatures, but temperatures will rise steadily throughout next week, such that we should be back to normal temperatures in the mid-upper 40s by the end of next week.

Rest of today – snow is already tapering off over the area, with widespread snowfall totals of between 4-8″ reported (largely in line with forecasts). Any remaining precipitation should completely clear the area within the next couple of hours.

Friday – we endure what we all hope will be the last day of temperatures in the low-mid 20s as cold, dry air filters in behind this storm system.

Saturday – high pressure moves in over the weekend, with temperatures Saturday edging up to around freezing.

Sunday – fair weather continues, but perhaps with more clouds on Sunday as some weak impulses of energy move over areas well to the north of NYC. High temperatures will increase to the low 40s.

Monday – the warming trend continues as spring approaches, high temperatures continue to warm into the mid-40s under partly cloudy skies.

Finally leaving the Arctic air behind?

A large scale warming trend is forecast to take hold over much of the US during the medium term. Temperatures next week should warm progressively such that by next Friday, we’ll be looking at (gasp) high temperatures near 50. The week after, on the cusp of spring, almost the entirety of the Continental US is forecast to experience warmer than normal temperatures, with the exception of Texas, and New York into Southern New England. However, we are forecast to be in normal range of temperatures for this time of year, which means mid-upper 40s. Not quite flip flops and t-shirt weather, but a positive trend nonetheless.

NYC Weather Update – Feb 24, 2015

February 24, 2015Climate, NYC, Rain, Snow, Storms, Weather Update, Weekendarctic, arctic air, arctic cold, cold, cold front, new york city weather, nyc weather, nyc wx, snow, winter, winter weather, winter weather nycLei Zhao

After that brief “warmup” during the weekend, we’re once again mired in Arctic cold air. This cold trend continues with a reinforcing shot of cold air as a cold front sweeps through Wednesday. Behind that, high pressure builds in over the area for the end of the week and into the weekend, ensuring another prolonged stretch of chilly, much below normal temperatures.

Wednesday – ahead of what will a dry cold front passing through, high temperatures may be able to climb to just about the freezing mark under mostly sunny skies.

Thursday – once the cold front moves offshore, an area of low pressure will strengthen, but remain well offshore of the area. However, precipitation may still make its way over the region, especially the far eastern areas. There’ll be a chance for snow flurries further west in the city. Temperatures will be back in the mid-20s again in the wake of that cold front.

Friday – clearing skies will be accompanied by stagnant cold temperatures with highs again in the mid-20s.

Saturday – as you’ll se below, a strong 1040mb area of high pressure will be parked over the Ohio Valley will be responsible for the sunny, but cold temperatures through at least Saturday night. Highs Saturday may approach 30ºF. Normal highs for this time of the year are closer to 40ºF.Looking Ahead

814temp.new — Climate Prediction Center’s 8-14 day temperature outlook for March 4th to March 10th, with our region in an area expected to experience below normal temperatures.

The beginning of next week looks to feature a fairly active pattern, with two storm systems passing through, one on Monday, and another on Wednesday. With the current track of the second storm, it looks like we are going to be on the south side of the low pressure center. This would allow for warmer air to wrap into the area. We could top 40ºF again, but the tradeoff will be a slushy, wet day maybe with some mixed precipitation to start. Once this second storm passes through, we return to cold temperatures once again.

NYC Weather Update – Feb 16, 2015

February 16, 2015Climate, Freezing Rain, NYC, Snow, Weather Updatearctic air, arctic airmass, cold, cold front, extreme cold, freezing rain, high pressure, low pressure, snow, weather, winter weatherLei Zhao

Sunday night’s lows were the coldest of the year thus far, indicative of the coldest airmass to hit the area in recent memory. Again, according to climatology, the last time New York City itself hit a low of zero was in January 1994. Unfortunately, the cold snap does not show any signs of abating during the week, although the first half of the week will see daytime high temperatures in the mid-upper 20s as opposed to the teens. We’ll finish the week off back into the teens before a warmup to above freezing with an approaching storm system this weekend. Behind that – you guessed it, another round of arctic air and abnormally cold temperatures.

Rest of today – cold and overcast, with high temperatures not even getting to 20 in the city. Snow should begin falling overnight, with generally light accumulations by daybreak.

Tuesday – slightly warmer with high temperatures in the mid 20s, but also with a chance for snow as a storm system now dumping snow across a vast swath of the South passes well to the south of us. We could still end up picking up 2-5″ of snow in the city, with higher amounts along the south facing shores of Long Island and minimal accumulation north of I-84.

Wednesday – a weak cold front will pass through Wednesday, and may give us a small chance for light snow, otherwise, expecting cloudy skies with high temperatures in the mid-upper 20s.

Thursday – behind that cold front, we get our next shot of Arctic air, with overnight lows into Thursday struggling to hit 10 in the city, and zero and below in outlying inland areas. Daytime highs will only be in the mid-teens despite ample sun. Thursday night, we might get another shot at low temperatures hitting zero in the city, with lows below zero across most inland locations.

Friday – basically a repeat of Thursday, sunny but with brutally cold temperatures in the mid-teens.

Over the weekend – watching for the development of a storm system that could bring some wintry mix/freezing rain to the area, but finally give us a break from below freezing temperatures.

More Cold on Tap to End February

After the weekend storm, we get yet another reinforcing blast of Arctic air to end the month of February. Below, you’ll see the Climate Prediction Center‘s 8-14 day outlook spanning February 23 – March 1. We’re in a region with a greater than 60% probability of experiencing below average temperatures for this period.

Climate Prediction Center 8-14 day outlook for Feb 23 - Mar 1 — Climate Prediction Center 8-14 day outlook for Feb 23 – Mar 1

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

December 4, 2014Climate, Cool Images, Drought, Flooding, Noreaster, NYC, Outside of NYC, Rain, Storms, Weather Update, Weekend, Western UScalifornia drought, california storm, climate, drought, flooding, heavy rain, meteorology, nyc weather, nyc wx, pac energy, pacific storm, rain, weather, west coastLei Zhao

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.

gfs_namer_042_1000_850_thick — 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.

gfs_namer_084_1000_850_thick — 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.

Screen Shot 2014-12-04 at 12.08.35 PM — Map of California with drought condition layer (reds/oranges), and rainfall totals from yesterday

Epic Lake Effect Storm

November 19, 2014Climate, Cool Images, Outside of NYC, Snowblizzard, buffalo, buffalo bills, buffalo blizzard, buffalo lake effect snow, buffalo ny, lake effect snow, november blizzard, record snow, snow, snowstormLei Zhao

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!

instagram_direct-wilfuen-857229331053732246_16330055 — 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.

Screen Shot 2014-11-19 at 6.58.17 PM — Measurements of snowfall around Buffalo – check out that 57″ number south of Elma, NY

ruc_snow_precip_24hr_2014111905_Southern_Great_Lakes — 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.

LZ | Weather

Weather updates & posts for NYC region