Tag Archives: hail

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 Weather Update – Jun 19, 2017

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The weather on Sunday turned out to be a real gift for fathers in the region, yielding a lot more clear skies than anticipated going into the weekend. We could have a rough start this week with possible severe weather, and another chance of rain mid-week. A tropical system forming over the Gulf of Mexico bears watching this coming weekend.

Rest of today – humid and warm with high temperatures in the low to mid-80s. Mostly sunny to start. All the ingredients for possibly severe thunderstorms will be in place this afternoon and evening. A flash flood watch is in effect for most of the area west of Long Island. The Storm Prediction Center has placed some of the region west of the Hudson River under an enhanced risk of experiencing severe weather with the city itself in a slight risk area.

A vigorous cold front will move east towards NYC today. As we can feel, the airmass ahead of the front is saturated and warm. The more sun we get before the front approaches, the greater the destabilization in the atmosphere. The cold front will line up with the flow of the jet stream, which will favor line segments and training of storm cells repeatedly hitting the same areas (flash flood warning is in place because of this).

Timing of the leading edge of the storms appears to be around 5pm. Any storms or substantial cloud cover ahead of this would decrease the severe potential. Primary threat along this leading line of storms would be damaging wind gusts with a small chance for hail and a couple isolated tornadoes.

Behind this leading line of storms, we could see a slight break around 8PM, but then more rounds of moderate to heavy rains that could lead to flash flooding.

Tuesday – severe weather and rain should dissipate fairly quickly after midnight. Decreasing clouds in the wake of the cold front though high temperatures remain similar to today due to the influence of southwest winds.

Wednesday – mostly sunny with high temperatures in the low-80s. A chance for rain in the afternoon, but much milder and less widespread than today.

Thursday – mostly sunny again, with highs in the low-80s again.

 

Potential Tropical Storm in the Gulf

Two possible tropical systems are churning, one east of the Windward Islands and the other crossing over the Yucatan into the Gulf of Mexico. The latter system may have a tangible impact in terms of bringing tropical moisture to the area this coming weekend.

 

 

 

 

 

 

NYC Weekend Weather – Mar 17, 2016

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Meteorologically, March is a month of highly changeable weather that can swing from one extreme to another. Thus far this month, we’ve seen snow, and record warm temperatures near 80ºF. This week is no different, and it ends with the possibility for a significant coastal storm that could bring accumulating snow to the region to ring in the official start of spring!

Rest of today – warm, with partly sunny skies and high temperatures in the mid-60s. An unstable atmosphere looks primed to spawn a few scattered thunderstorms. Atmospheric dynamics are supportive of strong wind gusts and possibly small hail with any storms that form this afternoon. Some of these storms could approach severe limits. Based on the latest High Resolution Rapid Refresh model output, there look to be two batches of storms, one impacting the region around 2PM, then again around 5:30PM. At the time of this post, two storm cells were moving slowly east over southern Bergen County and the western Bronx respectively.

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Friday – temperatures cool off into the low-mid 50s tomorrow, with a slight chance again for some afternoon showers, though nothing quite as significant as today.

Saturday – an area of polar high pressure will move over southeastern Canada, setting the stage for the winter storm Sunday. Saturday, however, will be a pleasant, sunny day, but temperatures will be below average in the low-mid 40s.

Sunday – all eyes turn to a developing coastal storm/Nor’easter. Forecast models are having a rough time handling this storm, with wide variances noted among some of the models from day to day. Given the uncertainty at this time, only a couple days before the expected onset of the storm, it is difficult to guess at the snowfall accumulations from this storm. One thing that is well understood at this point is that temperature profiles will support a primarily snow event, with some rain mixing in at the coast. High temperatures Sunday will struggle to hit 40ºF. Snow should begin in the morning, mixing with rain in the afternoon Sunday afternoon before transitioning again to all snow overnight. A slight variation in the forecast storm track either west or east could result in dramatically different snowfall totals – more updates to come.

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Monday – temperatures rebound back into the mid-40s under partly sunny skies following the passage of this late season snow storm.

 

 

Deep South Severe Weather Outbreak – Apr 28, 2014

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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
Major severe weather outbreak over the Deep South viewed from space

NYC Weather Update – Apr 21, 2014

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Brilliant start to the week this Monday with comfortable and seasonable high temperatures in the low-mid 60s.

HPC forecast

Tuesday – A cold front will rapidly approach the region from the west. Ahead of this cold front, warm, moist Gulf air will flow in, allowing for high temperatures to edge close to 70. Given the moisture content and warm temps, there is some potential for enough instability in the atmosphere to support the growth of thunderstorms later in the afternoon hours. Some of these storms could produce small hail. Thunderstorms, should they form, would be mostly limited to inland areas west of NYC as the marine layer near the coast tends to exert a stabilizing influence.

Wednesday and Thursday will be similar weather-wise with high temperatures suppressed in the upper 50s to low 60s due to the influence of strong winds from the north and northwest in the wake of the departing cold front. We should see clear and sunny skies both days. Excellent conditions for radiational cooling on both nights will allow lows to drop into the upper 30s and low 40s across the region.

The next chance for rain will be this Friday into the weekend with another cold front moving in from the middle of the country.

Really Cool Graphic – All Reports of Severe Hail from 1950-2013

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Another neat graphic from Storm Prediction Center’s SVRGIS: all reports of severe hail over .25″ in diameter from 1950-2013! Again, note the relative scarcity of severe hail west of the Rockies, but look at the density of hail reports over Mississippi and Georgia. Also, check out the dense patch of hail reports just east of the Front Range in Colorado.
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