Category Archives: Storms

Deep South Severe Weather Outbreak – Apr 28, 2014

April 28, 2014Outside of NYC, Severe Weather, Storms, Thunderstorms, Tornadoesalabama, gif, hail, louisiana, mississippi, satellite, severe weather, severe weather outbreak, tennessee, thunderstorms, tornado outbreak, tornadoesLei Zhao

A major severe weather outbreak is currently underway for portions of the Deep South from Louisiana up through Tennessee, extending east from the Mississippi to western Alabama. As you can see in this satellite image, there are numerous supercell thunderstorms with high cloud tops piercing into the tropopause, indicative of extremely strong updrafts. Low level helicity (a measure of the vorticity and spin imparted on the air) is also high, along with abundant moisture and convective available potential energy (CAPE) will continue to fuel dangerous storms capable of spawning multiple tornadoes, damaging wind gusts, and severe hail.

Major severe weather outbreak over the Deep South viewed from space

NYC Weekend Update & Severe Weather in the Plains

April 24, 2014NYC, Outside of NYC, Rain, Severe Weather, Storms, Thunderstorms, Weather Update, Weekendforecast, great plains, plains states, rain, severe weather, severe weather outbreak, showers, thunderstorms, vorticity maximum, weatherLei Zhao

The atmosphere over the area the past couple days has been both exceptionally dry and abnormally cool. This trend will end Friday with the approach of a cold front and low pressure system. Because the air mass currently in place is so dry, it will be difficult for the air to moisten at the outset Friday. Thus, forecasters are calling for a mostly dry day with increasing cloud cover, and rain showers moving in over the course of evening and overnight hours. High temperatures Friday will remain in the low 60s.

North American Model simulated radar image for Saturday @ 2PM EST

Saturday will remain a cloudy day with the chance for showers diminishing but still present. As the simulated radar image above suggests, there should be a break in precipitation between Friday evening and Saturday afternoon. However, it does appear that there is enough upper air support for afternoon showers and even some scattered thundershowers are possible Saturday afternoon. High temperatures will be warmer in the upper 60s. Skies should gradually clear once showers pass through, so the latter half of the day will still be sunny.

Sunday temperatures will cool off again with the passage of the cold front Saturday, however, sunny skies will return with high pressure building. Temperatures should be pleasant in the low 60s. Monday looks at this point to be a clone of Sunday.

Severe Weather in the Great Plains Sunday

It’s definitely severe weather season at this point in the Plains States and Tornado Alley. These areas have been repeatedly pummeled the past few days by severe hail storms. This weekend promises to be no different. As you can see below, a strong low pressure center is forecast to develop in the lee side of the Rockies Sunday with central pressure as low as 988mb.

Meanwhile, in the upper atmosphere, a vorticity maximum (see below) is forecast to form, with an area of strong divergence just to its east near the forecast center of the surface low. Upper level winds will be largely unidirectional. These are all ideal conditions for a severe weather outbreak. As a result, a wide swath of the Plains States from central Texas through Oklahoma, Kansas, and into Southeastern Nebraska have been placed under a Slight Risk area for severe weather by the Storm Prediction Center.

Note the strong low pressure center forecast to develop over the lee side of the Rockies - central pressure of 988mb — Note the strong low pressure center forecast to develop over the lee side of the Rockies – central pressure of 988mb

Upper air charts for Sunday afternoon. Note the strong vorticity maximum (area of dark red) over eastern Colorado.

Increased Pollution in Asia = Stronger Pacific Storms

April 20, 2014Climate, Rain, Stormsasia, china, climate, condensation, pacific ocean, pacific storms, pollution, weatherLei Zhao

pollution in china — Buildings in Lianyungang, China, are shrouded in smog on December 8, 2013. Aerosol pollution from Asia is likely leading to stronger cyclones in the Pacific, more precipitation, and warming temperatures at the North Pole. – National Geographic

A recently published study a by a Texas A&M team led by professor of atmospheric sciences Renyi Zhang points to a possible link between increased air pollution from Asian sources and stronger Pacific storms. There are implications for global climate, including impacts on El Niño. Stronger Pacific storms would lead to increased precipitation in places like the Pacific Northwest.

At its most basic level, the theory behind this study is a fundamental to atmospheric science and is well understood. Water vapor that makes up clouds first need condensation nuclei, such as salt, dust, or in this case, pollutants in order to coalesce around and form clouds. An increase in the number of available condensation nuclei should in theory lead to more robust cloud growth, which allows for more energy to be released into the atmosphere through the latent heat of condensation. This in turn will allow for stronger convective clouds, thunderstorms, and cyclonic storms.

NYC Weather Update – Apr 15, 2014

April 15, 2014NYC, Rain, Snow, Storms, Thunderstorms, Weather Updatecold, cold front, nyc, rain, snow, weather, winter is not overLei Zhao

Wet, windy, and cold conditions will predominate our weather today. We’ve already hit our high temperature for the day and will see temperatures continue to plummet throughout the course of the day as rain and the attendant strong cold front moves in later this afternoon. Gusty winds in excess of 40mph, and some rumbles of thunder are possible in the stronger rain showers.

The heaviest rain will be this afternoon/evening, ending gradually overnight. Behind the cold front responsible for this heavy rain, a biting northwest wind will drop temperatures down into the low-mid 30s! Again, there is some small potential for snow flurries across NYC during the tail end of this storm.

We could be looking at rainfall totals up to 2″ in the area, crazy wet for this time of year. Now, Wednesday, you’ll feel the impact of the passage of that cold front, as northwest winds will persist around 15-20mph, suppressing high temperatures in the mid-40s, much below the seasonal average.

Thursday and Friday will both be dry days with high pressure moving over the region, but high temperatures will remain below normal with an onshore breeze blowing in from the east and northeast. Overnight lows both days will remain quite cold in the mid-upper 30s. You thought you didn’t need that winter weather gear anymore, eh?

NYC Weather Update, Heavy Rain, Lunar Eclipse – Apr 13, 2014

April 13, 2014NYC, Rain, Snow, Storms, Weather Updatecold, cold front, lunar eclipse, nyc, rain, snow, weatherLei Zhao

This extended period of pleasant weather is about to come to an abrupt halt early this week. We do have one more day of decent weather in store Monday, when high temperatures will again hit 70 under cloudy skies. You’ll notice increasingly humid conditions as a breezy south wind continues to pump Gulf moisture our way.

Tuesday gets nasty, showery rain should begin to overspread the area during the morning hours, however, the heaviest rain should occur later in the afternoon and evening hours. High temperatures will be significantly cooler Tuesday with highs around 60 due to the clouds and rain, and a stiff south wind increasing from 15mph to 25mph later in the day. As the cold front passes through the area, much colder air will flow in, overnight lows will be only in the mid 30s. There is a chance for snow flurries to occur during the night, although accumulation is unlikely.

NAM simulated radar imagery for 8PM EST Tuesday

Precipitable water forecast, for as much as 1.25-1.5" of rain across the area. — Precipitable water forecast, for as much as 1.25-1.5″ of rain across the area.

Wednesday you’ll feel the effects of the passage of the cold front. Although skies will be sunny, high temperatures will struggle to even top 50. The cool trend should continue until the end of the week, with highs Thursday again in the low 50s.

Sadly, due to the expected cloudy conditions, we’ll most likely not be able to see the upcoming lunar eclipse.

NYC Weekend Weather Update – Apr 11, 2014

April 11, 2014NYC, Rain, Storms, Weather Update, Weekendgulf, heavy rain, nyc, rain storm, storms, warm, weather, weather update, weekendLei Zhao

We’re going to have a splendid weekend weather-wise in the NYC region. There will be some rain later this evening and into the overnight hours, but things should dry up before sunrise Saturday. High temperatures today will be comfortable in the mid to upper 60s, with western portions of the region possibly topping 70. The south wind will tend to keep inland areas warmer than coastal portions where the wind will be bringing in colder air off the Atlantic where sea surface temperatures are still only in the 40s.

Projected radar reflectivity for about 8PM EST, when we can expect the bulk of the rain for Friday night.

Once the rain lifts out, Saturday is shaping up to be a gorgeous day, with sunny skies and high temperatures in the mid-upper 60s in NYC. Inland areas again will see even higher temperatures with highs near or above 70, while eastern portions of Long Island will see temperatures in the lower 60s due to the continuing cooling influence of southerly winds off the ocean.

Southerly winds will continue to usher in increasingly warm and moist air Sunday with high temperatures in the low 70s inland and in western portions of the region, mid-upper 60s in NYC, and cooler temperatures in the east and coastal CT.

Monday will be the warmest day of the stretch, with highs easily topping 70 area-wide, again with the exception of coastal waters in eastern Long Island and CT. Dense fog may develop overnight Sunday due to the increasingly saturated air mass moving into the area.

Tuesday will be a messy day with a strong cold front moving in from our west. Temperatures will be significantly cooler, with highs probably only in the mid-50s. The Hydrometeorological Prediction Center is forecasting a significant rainfall event. This sharply tilted cold front is associated with a strong low-level jet streak, which will help usher in very moist air from the Gulf.

Note the extremely meridional (north-south) orientation of air flow on Tuesday, indicating a strong frontal boundary

Check out the swath of forecast total of 2.5"+ of rainfall Monday-Tuesday in our area! — Check out the swath of forecast total of 2.5″+ of rainfall Monday-Tuesday in our area!

After Tuesday, get ready for a serious cooldown, as temperatures behind this strong cold front will only be in the mid-upper 40s!

NYC Weekend Weather – Apr 4, 2014

April 4, 2014NYC, Rain, Storms, Weather Update, Weekendcold front, gif, nyc, rain, satellite, storms, weather, weekendLei Zhao

A chilly start to the weekend as we have cold easterly winds off the ocean, and a deck of clouds overhead. Rain will pick up in coverage and intensity as the day goes on, and it promises to be more or less a washout tonight.

Cloud deck building over the area, bulk of the actual rain is still off to our west over Central PA

Fortunately, the frontal system responsible for the rain will clear out of the area by Saturday. Sunny conditions will prevail, with winds turning from the east to the west and picking up to 15-20mph by the afternoon. High temperatures should top out around the mid-upper 50s, right about average for this time of year. Clear skies overnight Saturday will allow for good radiational cooling, and low temperatures could dip into the mid-upper 30s across the region.

Sunday promises to be the best day of the weekend, with high pressure firmly in control over the region. Sunny skies should allow for a mild day with high temperatures approaching 60.

The next storm system moves into the area later Monday into Monday night, with another chance for rain. Temperatures Monday could top 60 again with warm air flowing ahead of an approaching cold front.

NYC Weather Update – Apr 3, 2014

April 3, 2014Cool Images, NYC, Rain, Storms, Weather Update, Weekendclouds, gulf stream, nyc, rain, satellite, weather, weekendLei Zhao

Get out there and enjoy the sunny, mild weather while if you can today. We caught a nice break and got enough sunshine today that we’ll probably top 60 in quite a few spots around NYC. Clouds will increase over the next couple hours. Conditions will steadily deteriorate as a surface low pressures system currently spawning some severe weather over the Plains states tracks northeast into our area. Friday – keep the umbrella handy as periods of showers are likely to occur throughout the day, with increasing coverage and intensity later on in the day into the overnight hours. An steady onshore breeze will usher in much cooler air off the ocean (sea surface temperatures offshore of the region are only in the upper 30s to low 40s). As a result, high temp will hover in the mid 40s.

Saturday – the storm system bringing us rain Friday into Saturday will advance a warm front through the area, and we’ll see a rebound in temperatures and gradually clearing skies. High temps could again top 60.

Sunday – another pleasant and mild spring day as high pressure moves into the area. Mostly sunny skies with a high again near 60.

Monday – our next shot at rain will come Monday-Tuesday of next week, with a storm system forecast to develop in the Gulf. This storm will track northeast through the Ohio valley into the Great Lakes, and a trailing cold front will bring us some steady rain. High temperatures Monday will be around 60 with warmer air flowing from the southwest ahead of the cold front. Long Island and CT shorelines will see cooler highs with an onshore flow.

Screen Shot 2014-04-03 at 1.56.38 PM — Our next shot at rain – a low pressure system moving from the Gulf into the lower Great Lakes, and a trailing cold front.

NYC Weekend Weather Update – Mar 29, 2014

March 29, 2014NYC, Rain, Storms, Weather Update, Weekendflooding, nyc, rain, rainstorm, saturday, storms, weather, weekendLei Zhao

If you’re getting ready to venture out this evening make sure to bring an umbrella and wear your rain gear as a heavy rain event is in store for the New York City area. This will be an extended rainfall event leading into Monday. temperatures today will peak at around 50, near normal. The heaviest rain will be falling from approximately 8 p.m. tonight into the overnight hours. Winds will be at around 25-35 mph. Parts of the area are forecast to receive between 1.5″-3″ of rain in the next 48 hours, which could lead to some minor flooding in poor drainage urban areas and small creeks.

So, in general expect conditions to gradually deteriorate through the day and the intensity of rain to pick up. Rain will continue on Sunday, albeit with diminished intensity. Temperatures will hold steady around 50.

Refer to the diagram below, which represents the North American models guidance for this evening at around 8 p.m. Note the areas of blue and bright blue that correspond to rainfall rates anywhere between .75″ to 1.5″ per hour.

Rain will diminish by Monday afternoon as the low pressure center responsible for the heaviest rains moves off to the northeast.

High pressure will move in Tuesday, with a weak cold front moving through later Tuesday. This frontal boundary is not forecast to produce any precipitation. Ahead of this frontal system, we’ll see temperatures rebound to seasonal levels in the mid-upper 50s and partly cloudy skies. Wednesday will likewise be a seasonable day with mild temps near 60.

Light rain is possible Thursday, Friday, and Saturday of next week, but it’s much to early to be certain. GFS model also shows a possible coastal storm for next Tuesday.

NYC Weather Update – Mar 27, 2014

March 27, 2014Climate, Northwest, NYC, Outside of NYC, Snow, Storms, Weather Update, Weekend, Western USgfs, landslide, mudslide, navgem, nyc, oso, qpf, storms, weatherLei Zhao

We’re entering into a pattern of active weather through the weekend and into early next week. Today will be dry and pleasant, though well below normal with highs only in the mid 40s.

High pressure will move east of NYC before a cold front approaches from our west on Friday. Southwest flow around the high pressure center and ahead of the frontal boundary will usher in milder, moist air from the southeast. Temperatures on Friday will be near normal in the mid 50s. As the front passes through, expect periodic rain showers throughout the afternoon hours.

Saturday – a second frontal system is forecast to spawn a low that will track offshore of the East Coast, bringing a second round of rain to the area. This round will be heavier than Friday’s, with ample moisture available for the storm to draw on. With the clouds and rain, high temperatures will be suppressed to around 50.

Sunday – there is some uncertainty about how quickly the low impacting us Saturday will exit the region. At this time, it does appear that rain will continue through portions of the day. Should the low be slow to exit, colder air could work into the system allowing for accumulating snow Sunday night! High temperatures Sunday will be in the mid 40s.

Monday – should be a fair day, dry, with high temperatures near normal in the mid 50s. So, even if it snows on Sunday, the snow will melt rapidly. Next shot at precipitation comes with another frontal system Tuesday.

Check out the cumulative quantitative precipitation forecast from the National Weather Service’s Weather Prediction Center for Thursday through Sunday morning. Note that our area is forecast to receive as much as 2.5″ of precipitation through Sunday. Also, there are pockets of as much as 4-6″ of precipitation forecast for the West Coast. For California, that’s some good news as it will help with the drought conditions, but as we saw with Oso, Washington mudslide this much precipitation in such a short span of time can lead to landslides. This is especially the case for Oregon and Washington which are no longer as drought-stricken and soil saturated from previous storms.

Below is a NAVGEM forecast model run depicting two storms simultaneously impacting the West Coast and the Northeast on Sunday.

LZ | Weather

Weather updates & posts for NYC region