A correction from yesterday – I had said today may see less potential for severe weather. In fact, the Storm Prediction Center once again has most of the NYC metro area under a slight risk for severe thunderstorms later today.
Based on current satellite trends, it does appear there will be some breaks in the clouds this morning and afternoon. This will allow sufficient sunshine and daytime warming to fuel strong to severe storms across our region again later today. In the upper atmosphere, largely unidirectional winds from the south-southwest, a favorable jet stream set up, and approaching cold front suggest the potential for storms with damaging wind gusts and even some hail. Flash flooding is again a distinct possibility.
As you see below, portions of our area saw up to 1-1.5″ rain yesterday, and these same areas are in the target zone for severe storms today as well. With the upper level winds lining up from the south-southwest, training (where multiple storms hit the same location over a period of time) of storms is likely. This will enhance the risk for flash flooding.
A note about the term unidirectional winds: Unlike a hurricane, severe thunderstorms thrive on upper atmospheric energy, and unidirectional winds at all levels are more conducive to imparting a rotation on a rising parcel of air (rotating thunderstorms can produce tornadoes).
Otherwise, expecting a warm, humid day, with highs in the mid 80s and some sun before storms arrive later in the afternoon. It will be cooler and more comfortable tomorrow with this stormy cold front having passed us!
The Storm Prediction Center has placed the entire NYC metro area in an area for a slight risk of severe weather today. A strong low pressure center over the Great Lakes and its associated cold front are slowly making their way towards the Eastern Seaboard. Despite the cloudiness today, forecasters are still fairly confident that atmospheric conditions will be favorable for the formation of severe thunderstorms in the region. Based on current radar trends, these storms would most likely not be arriving in the NYC area until later this afternoon. The primary threat to our area will be damaging winds and torrential rain capable of triggering flash floods.
Tuesday will feature a similar set up for weather over the region, though there is less risk for severe weather tomorrow. However, strong storms are possible throughout the day and the risk of flash flooding is a distinct possibility. High temperatures will be in the mid 80s despite cloud cover, due to the influence of warm, humid air rushing in between the cold front and high pressure offshore over the Atlantic. This same warm, humid air mass is what will feed the storms for today and tomorrow. As you see below, the forecast rainfall total for today and tomorrow is as high as 3.6″ over Northeastern New Jersey, and ranges between 2.5-3″ for most parts of the Tri-State area.
Wednesday – we get a reprieve from the stormy weather as the cold front and storm system finally move east of NYC. Expect a cloudy start to the day with gradual clearing and conditions improving markedly. The next weather story for Wednesday through the end of the week is the cool, polar air mass that will be a dominant feature. High pressure will build in behind this storm system and usher in much cooler temperatures, with highs in the low 80s Wednesday-Friday, and overnight lows in the low-mid 60s in the city, and in the 50s north and west!
Thursday & Friday – expecting these two days to be essentially the same weather-wise, with high temperatures in the low 80s in the city (and upper 70s further north). Sunny to mostly clear skies for both days.
Lots to talk about on the last day of June, which brings with it the opening of a warm trend and possible mini heat wave. A stubborn low pressure system over the Plains States is pushing warm and humid air from the Gulf ahead of a leading cold front. As a result, Tuesday will feature warm, muggy conditions with highs in the upper 80s, maybe even touching 90.
Wednesday, that frontal boundary comes closer, and with the heat and humidity in place, we’ll have the right conditions for some pop-up showers and thunderstorms later in the day. However, coverage is expected to be widely scattered. Highs again will be in the upper 80s, possibly hitting 90.
Thursday -as the cold front makes its approach in earnest, a pre-frontal trough is forecast to develop, and this should help spark off more widespread showers and thunderstorms than on Wednesday. Expect high temperatures to be somewhat lower due to cloudy skies, but still warm and humid in the mid to upper 80s.
Friday (Independence Day) – A lot of weather forecasters were saying earlier this weekend that July 4th was going to be a nice day with no rain. Sadly, that doesn’t appear to be the case now, as the timing of that pesky cold front has slowed down somewhat. This does mean you could see rain and or thunderstorms during the day Friday and into Friday night, but at least the heat will break somewhat with temperatures only around 80.
Cold front right on top of us Friday could rain on your July 4th plans.
First Named Tropical System of the Atlantic Hurricane Season?
Over the weekend, a disturbance off the east coast of Florida began to show signs of increasing organization, to the point that the National Hurricane Center now gives the system an 80% chance of forming into a tropical depression in the next 2 days. If it does, then it will become the first named tropical system of the 2014 Atlantic Hurricane Season.
High resolution satellite image of the incipient tropical system off the east coast of Florida
Why does this matter to us? Well, as it currently stands, it appears this tropical system/possible storm may impact our weekend weather here in the Northeast. Some forecast models have this storm moving to the near offshore waters of the Northeast by Saturday (indicated in pink circle below). This could bring the potential for rain to parts of the Northeast, in particular, New England. Fortunately, it doesn’t appear as though this storm will strengthen much (below you see the lowest pressure at the center of 1012mb, for reference, normal pressure at sea level is 1013mb), and in fact, it will likely make a transition to becoming an extratropical cyclone/storm rather quickly after it moves north of Florida. Still, it’s a bit too early to tell just where this storm will go, so it bears monitoring.
Possible storm tracks as illustrated by several different forecast models
An unsettled week is in store for us after a spectacular stretch of warm, sunny conditions this past weekend. The good news is, it looks as though the pattern of rain during the week, but clearing and warm weekends is set to continue.
Tuesday – a high pressure center over New England will swing a backdoor cold front through tomorrow. This will lead to a chance of showers during the afternoon hours, with cloudy conditions otherwise and highs in the mid-upper 70s.
Wednesday – essentially a repeat of Tuesday in terms of sensible weather. A stationary front will sit just south of NYC and allow for an increasing chance of showers and possibly a few scattered thunderstorms. Temperatures will be in the same range as Tuesday.
Thursday will probably bring the best chance of significant showers and thunderstorms coming ahead of an approaching warm front. Cloudy again, with a chance of showers and thunderstorms throughout the day, and a high in the upper 70s.Friday – the warm front mentioned above will slowly progress through the area during the day Friday, once again bringing a chance for showers and thunderstorms, with mostly cloudy skies and highs once again in the upper 70s.
High pressure finally builds in during the day Saturday, which should lead to diminishing clouds, eventually mostly sunny skies for the rest of the weekend, and warmer temperatures in the low 80s.
What fantastic weather for the Memorial Day weekend! We topped off in the mid-80s across the area yesterday, and we’re likely to see another day with temperatures in the mid-upper 80s across the region (esp in interior portions of New Jersey).
Sadly, our stretch of summer-like temperatures is about to come to an end as a backdoor cold front (a front that does not approach from the west like most fronts do over this area) approaches the area from the north. Ahead of this cold front, temperatures are in the mid-80s and there is robust moisture in the atmosphere. This will provide the right ingredients for the possibility of severe thunderstorms later this afternoon and evening.
Possibility of Severe Thunderstorms This Afternoon
Current thinking is that these storms approach the NYC metro around 4-7PM during the evening rush hour. The Storm Prediction Center has placed NYC, western Long Island, Northern New Jersey, and much of the Hudson Valley under a slight risk area for severe weather this afternoon. By the way, slight risk in this context does not indicate that storms which occur will not be that severe, rather, it is denoting that the probability for severe storms is on the low side, and that coverage is not expected to be widespread. Just so you all are clear, the National Weather Service defines a severe thunderstorm as producing one or more of the following:
Wind gusts greater than 58mph
Hail greater than 3/4″ in diameter
A funnel cloud or tornado
A severe thunderstorm or tornado watch means that conditions are favorable over an area for the development of these types of weather hazards, however, no immediate threat has yet been identified. A warning means that a severe thunderstorm or tornado is imminent or already ongoing, which is understandably a much more dangerous situation. Anyway, the most likely threat for our immediate area are damaging wind gusts and hail, although a few isolated tornadic supercells cannot be ruled out.
Storm Prediction Center Day 1 Convective Outlook – we are in the slight risk area highlighted in yellow
Wednesday – by tomorrow, the cold front responsible for the possible thunderstorms later today will have moved through our area, however, there is still a chance for lingering showers on the backside of this frontal boundary. Also, since this is a backdoor cold front, temperatures will be significantly cooler tomorrow than today with an onshore easterly wind keeping high temperatures only in the mid 60s (about 20 degrees cooler than today).
Thursday – an area of high pressure will build into the area, but due to its position to our northeast, it will also continue to usher in onshore easterly/northeasterly winds that will keep our high temperatures below normal in the upper 60s. Otherwise, it will be a nice, sunny day.
Friday – another cold front will approach the region from the west and bring in the possibility for afternoon showers and thunderstorms. Slightly warmer with cloudy conditions and a high temperature near 70.
Saturday – high pressure will once again build in across the region and remain in place through the weekend. Therefore, am expecting pleasant, sunny conditions with about average temperatures in the mid-70s.
About that meteor shower… so as it turned out, the Camelopardalis meteor showers were a dud. Astronomers may have miscalculated the timing and/or amount of debris accumulated. Hey, it was the first time this particular shower was supposed to go down, so I guess you can’t blame them for not getting it right.
All preliminary indications are that this Memorial Day weekend should see fairly good weather, as you can read in the detailed discussion below. First, for your work week forecast:
For the remainder of the day today, there is a slight chance of a pop up shower or thunderstorm as cumulus clouds continue to build. This risk will cease as the sun begins to go down, and cuts off the heat source for these clouds. Overnight lows will fall into the low 50s in the city (not as cold as last night, as some clouds are expected to stick around early and stunt the potential for good radiational cooling), with 40s in the interior.
Tuesday will be the best day of the week, with high pressure briefly building in from the west. This will lead to mostly clear skies and warm temperatures in the upper 70s (also partially due to an incoming warm front).
Beginning Wednesday, we will see a period of unsettled weather as a relatively slow moving storm system approaches. This system will develop over the Great Lakes, and a warm front is forecast to be approaching our area during the day Wednesday. There will be an increasing chance of showers throughout the day as the warm front nears, with the best chance for precipitation in the late evening and overnight hours. Temperatures will be slightly lower than Tuesday in the mid-70s.
HPC’s Day 3 forecast for the US
Thursday there is a bit of uncertainty regarding the eastward progression of the warm front mentioned above. If the warm front has already passed over us, then we’ll be in the warm sector between the warm front and approaching cold front. This would lead to favorable conditions for some thunderstorms. Otherwise, we would expect mostly cloudy skies and a chance for more showery precipitation. High temperatures will be similar to Wednesday.
Friday, with the cold front Thursday having moved through and high pressure slowly building in, we would expect a good day weather-wise. However, as you see in the following image, the center of the now occluded low pressure is forecast to remain nearly stationary off the coast of New England. This is due to a blocking high over the North Atlantic (not pictured). Therefore, a chance of showers is forecast for both Friday and Saturday, with skies gradually clearing from mostly cloudy to mostly sunny Saturday. High temperatures Friday is forecast to be in the low 70s.
Now, the all important initial weekend forecast: as depicted above, high pressure building over the Great Lakes should progress generally southeast towards the Carolinas during the weekend. This should translate into improving weather each day during the weekend and increasing temperatures. Saturday, Sunday, and Monday should see high temperatures climbing from the low to mid 70s, and skies clearing to become mostly sunny.
For those of you reading this forecast who are traveling towards Oberlin and points west, the forecast for those parts is actually even better than for New York City in terms of sunshine, although, as you know temperatures will be slightly cooler in Ohio than here.
We’ve been fortunate that a persistent high pressure off of Nova Scotia has been stalling the arrive of a storm system earlier forecast to bring showers during the midweek period.
Our luck is about to run out, however, as the low pressure center and associated frontal boundaries will finally make their approach over the NYC area.
Thursday – overnight, a warm front is projected to pass through our area, bringing along a chance of drizzle, and the possibility for dense fog tomorrow morning as lower levels of the atmosphere become saturated with the coming southerly flow. Once the warm front passes over us, we will see a noticeable increase in temperatures, with highs forecast to be in the mid-upper 70s and possibly low 80s in interior portions of the region. Although the probability is low, there could be a couple showers and stray thunderstorms as well.
Friday – as the cold front associated with the low pressure center below draws closer, chance of precipitation will increase steadily during the course of the day. To start off, lighter showery precipitation should move in during the morning and early afternoon hours. Thereafter, heavier precipitation, and possibly thunderstorms, will move in especially during the evening and overnight hours. Due to the ground being somewhat saturated from the last round of rain we got, there could be some flash flooding in the heaviest down pours. Temperatures will be a bit cooler than Thursday in the upper 60s to around 70.
L and H correspond to approximate locations of surface low and high pressure centers. Notice the strength (high amplitude) of the associated upper trough and ridge
Saturday (BK Half Marathon Race Day) – good news for you runners out there as it appears the weather will cooperate for race day. The pesky slow-moving frontal boundary responsible for the rain on Friday will finally clear the area early Saturday morning, just in time for the start of the race. There may be some light showers early, but once the front clears conditions should start to improve. I would estimate start time temperature to be in the low 60s, with a high temperature forecast to be in the low 70s.
Simulated radar image from the North American Model (NAM) for Saturday at 8AM EDT
Sunday – a return to nice weather as the cold front has passed through and high pressure builds in temporarily. Partly cloudy with a high in the low 70s.
We have a similar setup as last week that’s bringing overcast and rainy conditions to the region. A warm front well to our south is causing southeasterly/easterly winds off the cold Atlantic to stream in and saturate the atmosphere. Today, temperatures will be cooler with highs in the upper 50s.
Another mature cyclone with areas of precipitation and associated frontal boundaries
Unsettled weather conditions will continue Friday with the approach and passage of the aforementioned warm front. Temperatures will be warmer in the upper 60s, with a chance for showers and thunderstorms throughout the day.
Saturday looks like a warmer copy of Friday, again with the chance for showers and thunderstorms during the day and with increasing chance for precipitation in the evening/night hours as the cold front depicted above makes its way through. High temperatures will be in the mid 70s despite the cloud cover.
Sunday should be the best day of the weekend (just in time for Mother’s Day), with the frontal boundaries having passed over, skies should clear and allow for temperatures to top out near 80 in the city.
Monday the period of good weather continues to start the next work week, with high temperatures again possibly hitting 80 and mostly sunny skies.
Are you wondering why today is so cool with highs barely touching 50, but tomorrow is forecast to have high temperatures in the low 70s? It’s because there’s a warm front currently situated to our south. Let me clarify the two most common types of frontal boundaries:
A warm front delineates a boundary where the airmass behind the front is significantly warmer than the airmass ahead of it.
A cold front, not surprisingly, applies to the reverse situation and delineates a boundary where the airmass behind the front is significantly colder than the airmass ahead of it.
Currently, a warm front sits south of us, causing an onshore flow (easterly winds) off the frigid Atlantic Ocean. Why the easterly winds? Looking at the image below, you’ll see yellow contour lines that demarcate isobars of pressure. In the Northern Hemisphere, air flows counterclockwise around a low pressure center and clockwise around a high pressure center. The counterclockwise flow also applies to the frontal boundaries attached to a low pressure center.
In our present situation, the air flows towards the east (counterclockwise) south of the west-east oriented warm front (in red), and then from the east to west north of it. Hence, we are experience very cool conditions, and the moisture being funneled off the Atlantic Ocean into our region is fueling these steady showers.
Current surface analysis from the WPC with my overlay showing movement of the warm front to our south.
We should actually see temperatures begin to rise overnight as the warm front pushes through the area. Once this occurs, we will be in what is referred to as the “warm sector”, which is an area that sits behind a warm front and ahead of an advancing cold front. This type of setup is favorable for the development of thunderstorms.
Therefore, Thursday will be a warm, cloudy day with high temperatures in the low 70s and a chance of showers and thunderstorms in the morning.
Friday, with the cold front having passed through, conditions will clear up and we’ll have a nice, sunny day, with temperatures near 70. There will be a chance for afternoon showers.
Saturday continues the trend of nice weather with another day in the upper 60s and mostly sunny skies. Again, there will be a chance for afternoon showers, especially inland where daytime heating can produce enough energy (and instability) to induce those showers.
One other note about today and tomorrow, and that’s the whopping headline numbers for how much rain is forecast to fall, with totals ranging from as high as 3″+ in the western portions of the Tristate to 1.5″+ in the east. This could easily cause flooding in poor drainage areas, small streams, and urban areas.
