All posts by Lei Zhao

NYC Weekend Weather – May 18, 2018

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The gray, gloomy, and wet weather trend that’s been semi-persistent for much of the last week continues into the weekend. Unfortunately, rain chances will exist both Saturday and Sunday. Cool temperatures to start the weekend will give way to warmer air. Things finally dry out going into the start of next week.

Rest of today – cloudy and cool with temperatures in the mid-60s. Slight chance for showers, though a strong area of high pressure well to our north in Quebec should help hold the line against rain associated with a stationary front draped west-east across Virginia and the Delmarva. Rain chances increase later into the overnight hours as this area of high pressure starts to lift to the northeast.

Saturday – the aforementioned stationary front will start to lift north as a warm front during the day Saturday. Ahead of this warm front, elevated instability could spark a few thunderstorms late in the day with an assist from vorticity maxima moving through in the mid-levels of the atmosphere. Temperatures will be cool, with clouds and rain showers throughout the day, maxing out in the low-60s. These temperatures will actually rise overnight once the warm front pushes through and allows for much warmer air to surge northward.

Sunday – warmer with high temperatures around 80°F, mostly cloudy with chances for showers and a thunderstorm particularly in the afternoon with the passage of cold front.

Monday – weather finally begins to dry up behind this cold front. High pressure will build once again and should give us a nice day with mostly sunny skies and temperatures in the mid-70s.

NYC Weather Update – May 15, 2018

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The story of this week will be the continuation of an unsettled weather pattern from this past weekend. Today, we will see a chance for some severe thunderstorms, and more rain chances lurk for us during the rest of this week, even extending into the weekend. Temperatures during this time will vary between normal and below normal depending on the extent of cloud cover and rain.

Rest of today – warm, humid, with a high in the mid-80s. Chances for severe thunderstorms increasing late in the afternoon. The Storm Prediction Center has placed our area in an enhanced risk for severe thunderstorms, with primary threats being damaging “hurricane force” wind gusts, as well as heavy rain. Some large hail and an isolated tornado are not out of the question. High resolution rapid refresh model simulated radar suggests the best timing of when the storms hit NYC will be around 6PM during the evening rush hour. This will make for a messy road home.

As you can feel already, the air is quite saturated (fog earlier this morning confirms this), this moisture-laden air will be one ingredient fueling storm growth later especially as temperatures warm with cloud-free skies allowing solar heating to quickly destabilize this air mass. At the surface, a cold front slowly approaching from the north and west will serve as the trigger that provides the lift necessary for storms to initiate late this afternoon. Aloft, the presence of a mid-level shortwave trough upstream of us will help prime the atmosphere, increasing lapse rates and instability aloft, while providing some additional divergence and lifting for storms. Lastly, late in the day, we will be in the right entrance region of a 300 mb jet streak, another favorable ingredient for divergence and synoptic lift. Winds at all levels above the surface will be fairly strong, producing a shear profile that favors strong winds. However, any discrete storms that form ahead of the main squall line could contain strong rotating updrafts favoring large hail and tornadoes. As usually, best chances for severe weather exist north and west of the city, away from the stabilizing influence of the marine layer near the coast. Storms will likely weaken as they hit NYC precisely due to this.

Wednesday – will be significantly cooler behind the cold front with high temperatures only in the mid-60s. Rain chances continue as the frontal boundary stalls and becomes stationary just to our south, in a similar arrangement to what took place over the weekend. This pattern looks to lock in for the rest of the week, bringing multiple chances for rain with it.

Thursday – a drier day mostly, with some slight chance for showers in the morning, then mostly cloudy with high temperatures rebounding into the upper-70s. Rain moves back in again overnight going into Friday.

Friday – cooler again with temperatures dipping into the mid-60s. Mostly cloudy with more chances for rain during the day as the stationary front mentioned above pushes back north as a warm front.

NYC Weekend Weather – May 11, 2018

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This Mother’s Day weekend will unfortunately feature mostly unsettled and cool weather, though no day will be a complete washout. A frontal boundary will just linger in our vicinity during this period, moving north as a warm front, then retreating south as a cold front. This will allow multiple subtle upper level disturbances to move along this boundary, and each of these will bring a chance for rain.

Rest of today – splendid day with sunny skies and just about average high temperatures around 70ºF.

Saturday – chance for rain early between 7-11AM, then a period of mostly cloudy skies until another round of showers with some thunderstorms rolls through in the evening between 8-10PM. Cooler with high temperatures in the mid-60s.

Sunday (Mother’s Day) – chance for showers in the morning, with steadier rain possible through early afternoon. Cool, with northeasterly onshore winds, and high temperatures in the low-60s. Rain chances should diminish later in the day.

Monday – drying out with temperatures in the low-70s and partly sunny skies.

Possible Tropical Storm Impacting the US During Memorial Day?

Consecutive runs of the GFS forecast model continue to suggest that a subtropical/tropical storm could develop in the western Caribbean off the coast of Nicaragua in the next 10 days or so. It’s far too early to be certain of this, but the trend is worth noting. Recent runs suggest that this storm could make landfall on Florida and then travel up the east coast.

NYC Weather Update – May 7, 2018

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High pressure hangs around the region most of the week and gives us pleasant, seasonable weather with high temperatures at or above average for most of the week. One chance for rain comes in the late week period with a cold front forecast to pass through the area. Otherwise, it will be a marvelous week of ideal spring weather.

Rest of today – mix of sun and clouds with high temperatures in the upper-60s.

Tuesday – mostly sunny with high temperatures in the upper-60s. This week, we benefit from cooling onshore breeze due to the synoptic set up over the Northeast. Contrast this to last week when we had very warm winds blowing from the southwest.

Wednesday – warmer with high temperatures in the mid-70s and sunny skies.

Thursday – rain chances late as a cold front approaches from the west. Otherwise mostly sunny with high temperatures in the low-70s.

NYC Weekend Weather – May 4, 2018

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After two days of record-breaking heat in the low-90s, a pattern change is on tap for the NYC metro area going into the weekend. Cooler conditions will prevail in the wake of the passage of a cold front, which could also bring rain and thunderstorms (possibly severe). Saturday should shape up nicely but rain chances return Sunday before a cooler start to the work week.

Rest of today – the Storm Prediction Center has placed portions of the region under a marginal-slight risk of severe thunderstorm activity today. We continue to be an increasingly moist warm sector east of an advancing low pressure center. As the cold front associated with this low pushes east, storms will initiate first along a pre-frontal trough during the day today (late morning-early afternoon), then again along the actual frontal boundary itself later this evening. It is the latter round of these storms that could push severe limits. There are limiting factors to this activity especially near the coast with more stable air present. Cloud cover will limit day time heating, reducing overall instability. And the earlier round of activity should serve to actually mitigate the later round of storms. Aside from the rain, it should be mostly cloudy with some breaks in the sun (that would increase chances for storms), with high temperatures in the mid-80s.


Saturday – cooler air moves in behind the cold front tonight while a weak area of high pressure builds. High temperatures should top out in the mid-70s with partly sunny conditions. Rain chances increase towards the overnight hours.

Sunday – cooler still with mostly cloudy skies and chances for rain. High temperatures only in the mid-60s as a weak disturbance passes to our south.

Monday – skies finally clear up with high temperatures moderating and warming into the upper-60s.

NYC Weekend Weather – Apr 27, 2018

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A wet end to the week will lead to a better first half of the weekend. Showers could occur again on Sunday, but we’ll once again dry out to start next week. A big shift in weather patterns will take place next week with a dramatically warmer air mass to move into the region. Summer-like temperatures in the low-80s by late next week will be a possibility.

Rest of today – cloudy with high temperatures in the upper-50s and rain. Rain beginning this morning, but tapering off in NYC by late afternoon around 4PM, just before the evening rush. Given the set up of winds from the south flowing over a warm front pushing though, some elevated thunderstorms are possible today.

Saturday – nice day on tap with mostly sunny skies and temperatures into upper-60s. Clouds increase late with the chance of scattered showers increasing overnight as a cold front passes through.

Sunday – lingering rain chance early, with conditions improving later and clouds diminishing. Cooler with highs in the upper-50s in the wake of the cold front above.

NYC Weather Update – Apr 24, 2018

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This week started off with a gorgeous, sunny day with above average warmth. Temperatures will remain largely at or above normal, with the exception of tomorrow as a storm system rolls through and brings us some rain. The end of the week may also see a chance for showers, but this will set the stage for us to enjoy another weekend of sunny, above average warmth.

Rest of today – increasing clouds as a storm approaches from the southwest. This increasing cloud cover should result in high temperatures a few degrees cooler than yesterday, topping out in the mid-60s. Overrunning precipitation will begin to fall late overnight in association with a warm/occluded front approaching from the south.

Wednesday – rain, with a thunderstorm possible. Mostly cloudy, and cooler with highs in the mid-50s.

Thursday – partly sunny with high temperatures warming back into the mid-60s as the storm system above exits to our northeast.

Friday – partly sunny with high temperatures again in the mid-60s. A chance for rain with a weaker storm system moving up again from our south.

NYC Weekend Weather – Apr 20, 2018

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The pattern of much below normal temperatures will finally break, albeit slowly, starting this weekend. After a soaker to start last week, and a gloomy, rainy Thursday, it will be nice to see a break from the rain. We won’t get another rain chance until Wednesday of this coming week.

Rest of today – mostly sunny with a gusty northwest wind as high as 25 mph, though sustained wind will be calmer in the 10-15 mph range. High temperatures in the low-50s.

Saturday – high pressure will begin to take firm hold of the weather in the region, yielding sunny weather with warmer temperatures in the upper-50s to near 60°F.

Sunday – another beautiful spring day with bright, sunny skies and temperatures near 60°F.

Monday – sunny, and warmer still with temperatures starting to creep into the low-60s.

NYC Weather Update – Apr 16, 2018

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This work week starts off with a serious soaking rain from a storm system that has impacted a wide swath of the southern US with multiple days of severe weather. Conditions improve tomorrow and Wednesday before another chance for rain on Thursday. The rain this morning has led to the issuance of flash flood warnings, and numerous reports of flooding have already come in, so take caution out there, especially if you’re out on the roads.

Rest of today – rain, heavy at times, with the threat for flash flooding and flooding possible as storms train and hit the same areas repeatedly. Some embedded thunderstorms have been occurring this morning, enhancing the heavy rainfall potential. Some areas could see rainfall rates of up to 1″/hr along with gusty winds in the 40-50 mph range. Temperatures will be rising into the upper-50s as a warm front approaches from the south.

Tuesday – improving conditions as the storm system responsible for today’s rain moves off. Cooler, with temperatures maxing out in the low-50s in the wake of a cold front and mostly cloudy skies.

Wednesday – the best day of this week with high temperatures in the mid-50s and mostly sunny skies.

Thursday – another storm system, albeit weaker, will impact the area. High temperatures should hover in the mid-50s with chances for rain and cloudy skies otherwise.

 

NYC Weekend Weather – Apr 13, 2018

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Despite it being Friday the 13th, if you were looking for some spring weather, this happens to be your lucky day. With our region in the warm sector of a large storm system far off to the south and west (which will bring severe weather to parts of the Mid-Mississippi and lower Missouri Valleys today), warm air will be surging from the south. This will give us a great start to the weekend, though things will shift dramatically by Sunday as a frontal boundary dances back and forth across the area. Wild temperature swings of 30ºF are possible with a much cooler day Sunday.

Rest of today – despite the cloud cover now, temperatures should still reach well into the mid-70s. Any breaks in the clouds would likely result in highs hitting 80ºF. There will also be a steady southerly breeze with gusts up to 20 mph.

Saturday – temperatures remain quite warm with highs again in the mid-70s. The warm front that swept north through the region last night, which brought the warm air along with it, will retreat south of the area as a backdoor cold front late during the day Saturday. Expect temperatures to drop rapidly after this backdoor cold front passes through – between 10-15ºF within as little as an hour. Increasing clouds will accompany this frontal passage.

Sunday – significantly cooler with easterly onshore winds in the wake of the backdoor cold front passage. This onshore flow off the still cold waters of the Atlantic will result in high temperatures only in the upper-40s. Periods of rain will also occur, especially later in the day with mostly cloudy skies otherwise.

Monday – the backdoor cold front will stall just south of us, then push back north as a warm front again. Temperatures will rise back towards around 60ºF prior to the arrival of a stronger cold front. This will be accompanied by steadier rain and even a couple rumbles of thunder are possible.