Category Archives: Storms

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 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 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 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.

 

NY Weather Update – Mar 19, 2018

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It sounds like a broken record at this point, but another week, yet another nor’easter with a chance of snow, arriving on the second day of spring no less! As with previous storms, how much snow we get will hinge critically on the storm’s track and proximity to shore. Looking ahead past the storm, temperatures remain subdued and below normal for this time of year.

Rest of today – sunny, high temperatures in the low-40s.

Tuesday – increasing clouds, with a chance for rain snow mix later in the day. High temperatures in the upper-30s.

Wednesday – snow developing overnight and continuing through the day. Accumulating snow currently forecast to be light in the 1-3″ range. This could increase though, based on current forecast ensemble totals ranging 5-6″. The caveat is that blacktop will probably be largely snow free due to the high sun angle.

Thursday – conditions improving overnight and mostly sunny skies with highs in the mid-40s. Snow should melt quickly with the high sun angle and temperatures.

NYC Weather Update – Mar 12, 2018

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Another week, another nor’easter! Luckily, this time around, the storm will stay outside of the notorious 40ºN 70ºW benchmark, meaning that impacts for NYC should be relatively light. On the backside of this storm, weather should be fairly innocuous and average for this time of the year.

Rest of today – increasing clouds ahead of this incoming storm. High temperatures in the mid-40s. Temperatures drop to near freezing overnight in the city, setting the stage for snow overnight as the storm approaches and rapidly strengthens.

Tuesday – lingering snow from overnight ends quickly in the morning or transitions to rain. When all is said and done, we might pick up 2-4″ of snow in the city. Temperatures will be marginal at best and the snow will probably have difficulty sticking to blacktop. There is an outside chance of more than 6″ but this probability is low. As you can see from the preceding graphics, the bulk of the storm, and its center will be tracking quite far southeast of the area. Winds will be shifting towards the northwest around 20 mph and high temperatures will only be around 40ºF due to the combination of wind, clouds, and precipitation.

Wednesday – an unsettled regime continues into Wednesday with some slight chance for a couple snow showers. Mostly cloudy with high temperature in the mid-40s.

Thursday – partly sunny, high in the mid-40s.

NYC Weather Update – Mar 5, 2018

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The second week of March brings another nor’easter. The week will start off calmly with temperatures about average for this time of year. Tuesday night into Wednesday, a nor’easter will impact the region. This time around, the primary threat will be possible heavy snow rather than high winds. There are signals for yet another nor’easter next Tuesday as well!

Rest of today – decreasing clouds, high temperatures in the mid-40s with winds diminishing.

Tuesday – the veritable calm before the storm, a mostly sunny day with high temperatures in the mid-40s again.

Wednesday – a low pressure system that tracks east from the Great Lakes will spawn a secondary coastal low offshore of North Carolina. This coastal low will steadily gather strength, aided in part by the presence of an upper-level jet streak and the divergence provided within the exit region of this jet. At this time, two main camps of models have the storm tracking either close to the coast or over the 40N 70W benchmark. The former solution would mean higher precipitation amounts but more potential for mixing at the coast due to the influence of warmer marine air wrapping in. The latter solution would likely yield all snow, but with less total precipitable water. Currently, forecasters are calling for between 5-10″ of snow and a winter weather advisory is in effect.

Primary low moving east from the Great Lakes region, secondary low formation off of the coast of the NC/VA border

High temperatures should top out in the upper-30s. The main snow event would occur Wednesday afternoon and overnight. Based on the NAM and GFS ensembles, it appears as of now that the highest confidence is for a 5-6″ event. Again, this could change with a shift in the storm track, and we won’t know where the heaviest bands of snow set up until the event begins.

NAM ensemble plume forecasts for snowfall totals in LGA
GFS ensemble plumes forecast for snowfall totals at LGA

Thursday – unlike the last storm, this one will exit relatively quickly. This reduces the overall impacts for wind and coastal flooding. Thursday should be a day of improving conditions with partly sunny skies and high temperatures back in the mid-40s.

NYC Weekend Weather – Mar 2, 2018

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March arrives as a roaring lion this year with a powerful nor’easter impacting the region during the first half of the weekend. A variety of hazards from snow to high winds to coastal flooding will affect the area before this nor’easter meanders its way out to the open ocean. Behind this storm, the large scale pattern shifts and much cooler air rushes in, displacing unseasonable warmth with more average temperatures for the week to come.

Rest of today – rain and snow mixing. Little to no accumulation expected. Winds increasing from north to northeast winds 20-25 mph to 30-35 mph with gusts as high as 60 mph near the coast possible later today. Moderate coastal flooding possible over multiple tide cycles tonight, and Saturday. These tides will be higher than normal since they are falling on the full moon (spring tides). Temperatures will hold steady in the upper-30s.

Overnight, an inland low and coastal low consolidated offshore of the Northeast and the coastal low has already rapidly strengthened to a minimum pressure of 984 mb this morning. Two branches of the polar jet have phased together, providing the energy for this robust storm. As the storm continues to deepen, the pressure gradient between it and an area of high pressure over the Upper Midwest will continue to increase, leading to stronger winds. Onshore flow of these winds from the north and northeast over an extended period of time are expected to bring coastal flooding. Periods of moderate to heavy rain could lead to flooding in general. Although the cold, northwest flank of the storm as it exits to the east will support snow (with its cold conveyor belt), accumulations at the coast should be limited. This is another story inland where heavy snow is expected in the Lower Hudson Valley.

Saturday – periods of moderate to heavy rain with snow mixing in continue overnight, but should taper off by the morning. Winds will diminish from the 30 mph range with gusts up to 55 mph overnight but will remain stiff in the 20-25 mph range from the north. Much colder feel with highs in the mid-40s under partly sunny skies.

Sunday – much nicer day, winds finally abating with high temperatures in the mid-40s and mostly sunny skies.

Monday – sunny, with high temperatures in the mid-40s.

NYC Weekend Weather – Feb 23, 2018

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A wet and unsettled weekend is coming up for NYC after a week that saw record-breaking warmth and large temperature swings. Back-to-back mid-latitude cyclones with their attendant warm and cold fronts will move through the area bringing a cloudy, gloomy feel, and plenty of chances for rain.

Rest of today – multiple rounds of rain showers possible through the morning and afternoon hours ahead of a warm front advancing from the southwest. Rain chances diminishing after around 6PM this evening. Overcast otherwise with a high temperature in the low-40s.

Saturday – overnight temperatures warming due to warm advection ahead of that warm front. We’ll end up in the warm sector of the first of these two mid-latitude cyclones on Saturday with high temperatures rising into the mid-upper 50s under mostly cloudy skies. Some chance for a scattered shower more likely later in the day as some post-frontal rain develops with a cold front exiting to the east.

Sunday – slightly cooler, high temperatures in the upper-40s. Another cloudy day, with rain continuing from overnight Saturday as first a warm front then a cold front moves through with this second storm system.

Monday – finally a dry day with mostly sunny skies and high temperatures in the mid-50s after this chain of storms!