All posts by Lei Zhao

NYC Weekend Weather Update – Apr 11, 2014

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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.
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
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 Weather Update – Apr 9, 2014

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A beautiful Wednesday today, and another superlative day on tap for Thursday. Plenty of sunshine both days with only some scattered fair weather, puffy cumulus clouds. Temperatures will be slightly above the average of 55 with highs topping out near 60. Tonight, clear skies and calm winds will provide ideal conditions for radiational cooling with lows near 40 in the city and much cooler in the outlying areas. Northwest winds today will turn to the southwest tomorrow ahead of an incoming cold front, so it will feel warmer tomorrow than today even though the air temperature is going to be about the same.

Friday we’ll see a chance for periodic showers during the day and into the overnight hours. High temperatures will hold steady around 60.

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Low pressure center with a trailing cold front moving through the area Friday

Once the cold front moves through Friday night, it will usher in a gorgeous weekend, with dry conditions, sunny skies, and high temperatures in the low 60s! Best weekend so far this spring, so definitely go out and enjoy it.

NYC Nowcast – Apr 8, 2014 @

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Quick update here: skies will gradually begin to clear as clouds associated with the rain storm last night move offshore. As you can see from the satellite image below, sunny skies are already entering portions of Northern NJ. Depending on the time we get under clear conditions, we could very well see high temps hit 70 except in Long Island and coastal CT, where an onshore southwest wind will keep things cooler.

Also of interest, check out the wave clouds out over Central PA! Just as objects in the path of a water can cause eddies and waves to form behind them, you can get the same effect with air flowing over mountain ranges. You can’t surf these (maybe with a glider?)
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NYC Weather Update – Apr 7, 2014

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Rain will start to pick up this evening, but the heaviest of the precipitation should hold off until the overnight hours. A low pressure center over the Ohio Valley will move northeast into the lower St. Lawrence Valley in Canada.

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GFS model output for 8PM tonight

Meanwhile, a secondary low will bring a warm front through Tuesday – with rain ending early and warm south winds, Tuesday will be a mild day with highs in the mid-60s and gradually clearing skies.

Wednesday and Thursday should both be spring-time gems with high temperatures in the upper 50s to near 60 and fair conditions.

Our next shot at rain will be Friday into the weekend with a low passing well to our north, but forecast models showing a trailing cold front with precipitation.

NYC Weekend Weather – Apr 4, 2014

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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
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.

Cool gif – Severe Thunderstorms in the Plains, Apr 3, 2014

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Check out this satellite loop of a line of severe thunderstorms over eastern Oklahoma extending northeast into western Missouri. You can see the classic telltale signs of explosive thunderstorm growth here. Notice how at the outset, the line of clouds near the center of the frame are relatively thin, but then balloon out as time goes by. What’s happening here is that the cumulonimbus (thunderstorm) clouds along this line are growing so rapidly that they are hitting the top of the troposphere. Since water vapor has a difficult time penetrating into the stratosphere, it gets forced out laterally instead. Indeed, the Storm Prediction Center in Norman, OK has issued a mesoscale discussion, along with severe thunderstorm warnings and tornado watches for much of the area.

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NYC Weather Update – Apr 3, 2014

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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. Screen Shot 2014-04-03 at 1.49.36 PMFriday – 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.

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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.

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Our next shot at rain – a low pressure system moving from the Gulf into the lower Great Lakes, and a trailing cold front.

NYC Weather Update – Apr 1, 2014

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Don’t be fooled by this gorgeous weather today (seriously).

A low pressure system forming in the lee of the Rockies, along with a nearly stationary frontal boundary draping down from a low moving into Canada will result in cloudy to mostly cloudy skies for the remainder of the week. There will be a chance for rain each day through Friday. The best chance for steadier rain will be late in the day Friday through Friday night and perhaps into early Saturday morning. This is associated with another area of surface low pressure and trailing cold front.

Note the frontal boundary draping across the region - this will give us a chance for showers each day Wednesday-Friday.
Note the frontal boundary draping across the region – this will give us a chance for showers each day Wednesday-Friday.

High temperatures will warm to near 60 Wednesday with a persistent south-southwesterly flow ahead of the aforementioned frontal boundary.

Thursday – with the influence of clouds and possible showery rain, temperatures will most likely hover around the mid 50s.

Friday – rain increasingly likely throughout the day Friday with high temperatures continuing to drop to around 50.

Saturday – temperatures will warm again into the upper 50s ahead of a cold front (and with a warm front forecast to swing through), however, it will be a cloudy day with a diminishing chance of showers through the day.

Sunday – the cold front will have passed through allowing for skies to clear, but temperatures will be cooler in the low 50s with winds from the northwest.

 

Next shot at precipitation comes Monday night into Tuesday with a surface low tracking from the Southeastern US.
Next shot at precipitation comes Monday night into Tuesday with a surface low tracking from the Southeastern US.

NYC Weekend Weather Update – Mar 29, 2014

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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.

nam-hires_namer_015_1000_500_thickRain 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.