In brief: The first potential non-Gulf system of the season faces an uphill battle in the Atlantic. It’s possible something tries to develop next week, but it’s more than likely going to end up sloppy.
Let’s start big picture and take a peek at the Atlantic basin this morning.
Satellite view of the Atlantic on Friday morning. (WeatherFront)
The standout feature is a tropical wave emerging off the African coast today. Over the next few days, this wave will track west through the Atlantic. Wind shear in the eastern Atlantic is actually not too bad at the moment. But dry air? Yeah, there’s a lot of that. Saharan dust plumage all over the Atlantic basin right now.
Saharan dust dominates. (University of Wisconsin)
That looks more like July than August, but either way it’s choked with dust. This should mean anything that develops or tries to develop will struggle a bit, if not a lot. Regardless, there’s an interesting split within the models about the future of this disturbance. The physical European model, the original gold standard is modestly bullish on development over the next 4 days, with about a quarter of the 51 ensemble members developing the system.
European ensemble development chances are modest but generally low over the next few days. (Weathernerds.org)
Some develop it and kill it off pretty quickly too. Go to the AI version of the Euro and the story is, well, pretty much the same.
European AI ensemble shows a similar outcome to the physical Euro. (Weathernerds.org)
And what of the current gold standard, the Google Deep Mind ensemble? Not much.
Google Deep Mind ensemble. (Weathernerds.org)
I will say, all the models have had their moments, good and bad with genesis of tropical systems. So I’m not going to read into anything here too much. That said, the one notable takeaway here is that even the models that do develop the system to any extent (mainly the Euro) are lukewarm on its ceiling. Meaning, if you get development, you’re probably getting a sloppy system with a low top end intensity. Sloppy systems deserve love too though, so we’ll watch to see what happens here.
With that in mind, it does not appear at the moment that this system will be a serious threat to anyone downstream. It’s a reminder that despite El Niño, despite the hostile Atlantic, despite the quiet forecast it’s still August and worth checking in on things from time to time.
No other concerns are seen at this time in the Atlantic.
In brief: We check in on the state of the tropics, how El Niño is already impacting the season, and what we may see in the coming weeks. We also discuss how to not fall for engagement bait.
It’s August 3rd as I write this, and suffice to say, it has been a delightful tropical season for those of us who don’t want major hurricanes impacting communities. Arthur, while not the full cause of flooding in Louisiana and the broader Deep South, remains the most notable of our two storms so far. Our ACE has accumulated to 2.6 units thus far, not the lowest we’ve ever seen, but certainly on the lower end of the spectrum of recent years.
We typically average about 10 units of ACE by this point in the season, although that still only accounts for about 8.5 percent of total hurricane season. So, we’re a long way from the finish.
How has hurricane season been so quiet? Well, for one, it’s normal to be quiet in the first 2.5 months of the season. We’ve seen some catastrophic examples of that going awry over the years, but by and large, those years are very much exceptions rather than rules. So, climatology is your friend. But beyond that, there’s been the El Niño that has been talked up to the moon over the last few months. And it’s worthy of the hype; it’s one of, if not the strongest El Niño we’ve seen to this point in the modern era. El Niño means wind shear in the Atlantic, and big El Niños mean big wind shear. This year? No different.
Generalized wind shear since January 1. (NOAA)
Other than perhaps a few days in early to mid-June, wind shear in the Atlantic basin has been average to well above average this season. The Gulf and subtropical Atlantic has been a bit more subdued, whereas the Caribbean has been raging with shear. So El Niño is doing its thing.
And in fact, this particular El Niño remains on pace to become a first ballot hall of fame event. This event has been building and building all summer long. When you look at the total depth of the water temperature anomalies, you can clearly see that this event is absolutely romping.
Sea-surface temperature anomalies are running 5 to 10 degrees above normal (Celsius) in the subsurface waters of the Tropical Pacific (NOAA)
As a sidebar, one thing I want to make sure the general public understands about this and the media ecosystem and content creation system today: You are going to hear people start making bold proclamations about El Niño and winter. Yes, winter. In August. It’s nonsense. People will cherry pick the most exciting (read: cold/snowy) model they can get their hands on for winter to basically draw you into engagement. They’ll couch it in language like, “This is only one solution, and it’s not necessarily likely to happen, but when I see this, I take notice!” It’s a digital dopamine hit. And it’s just not right, nor is it being a meteorologist. It’s picking a cold model because they know you, the reader or viewer gets excited about that, and it will spur you into engagement, which in turn helps you to feed the beast, as it were. It used to be rogue “social mediarologists” that did this, but it has gotten far worse and extended into professionals that know (or should know) better, particularly on the broadcast side of things. And a lot of the legacy media tries to draw you in with big, bold headlines too. Bottom line: If someone is selling you a historic cold or snowy winter right now, don’t buy the hype. Sure, there could be a storm or two — as happens almost every winter. That’s not exactly a forecast; it’s called climatology. This winter is likely to be historic in some way given the El Niño, but real history points toward either a very warm planet or high precipitation values and drought in various different parts of the globe.
Anyway, off the soapbox. El Niño is feeding the wind shear machine. The other issue? Water temps. The Gulf? Warm. The Caribbean? Less warm. The Atlantic Main Development Region? Not warm at all.
(Dr. Kim Wood/University of Arizona)
We are near climo in the deep tropics. And that’s not going to cut it with this sort of wind shear environment we are in. Basically, this points to development occurring through closer to home systems that could fire up if wind shear relaxes for even a couple days at the right (wrong) time. Or by waves, disturbances, or remnant fronts that make it closer to the much warmer subtropical latitudes off the East Coast or in the open Atlantic. We could still see a few weaker tropical systems out in the deeper Atlantic. But Cabo Verde season seems increasingly unlikely to replicate what Cabo Verde’s soccer team did at the World Cup this year.
Still, watch we will. But at this time, all looks quiet the next week or two.
In brief: We take a look at how models did, as well as some of the totals and causes of the extremely heavy rain that hit the Northeast this week. We also check in on the tropics, which look relatively benign on the Atlantic side for the time being.
Northeast recap
Back on Monday, we took a look at forecast rainfall for the upcoming days, noting that there were some decent risks for 5 inches or more of rainfall. Tuesday’s rainfall forecast through Thursday evening highlighted the Hudson Valley, western Connecticut, and northeast New Jersey for the highest rainfall totals.
Monday’s rainfall forecast through Thursday.
So how have we done?
72-hour rainfall totals ending at 11 AM ET Thursday. (WeatherFront)
A couple things. The overall forecast was decent. However, rain totals were underestimated in New York State and slightly overestimated in Connecticut. But overall, this was a decent forecast. The totals in the Hudson Valley up through the Capital Region of New York State were incredible.
Rainfall totals over the last 3 days centered over the Capital Region of NY. (NOAA NWS)
For Albany, Wednesday was the second wettest day on record (going back to 1874). Of the 10 wettest days on record in Albany, six have been produced via direct impacts from tropical systems, a seventh may have been related (8/31/1950) to interior landfalling storms in the Central U.S., and three were not directly affiliated with tropical systems, including yesterday.
Albany’s 10 wettest days on record. (NOAA)
So it’s unusual for Albany to receive this much rainfall from a non-tropical storm. Atmospheric moisture levels were in the 90th percentile in Albany Tuesday night into Wednesday and closer to the 95th percentile on Long Island. In other words, it was a deeply moisture-rich environment. If you look at the total precipitable water from 2 AM Wednesday, you can see almost like a miniature atmospheric river pointed right at the Hudson Valley.
A strong “tendril” of moisture pointed out of the southwest Gulf Stream and into the Hudson Valley Tuesday night/Wednesday AM (University of Wisconsin SSEC)
All this moisture, coupled with a slow-moving upper low oriented just right to allow bands of moisture to burst into the Capital Region continuously helped lead to some of those ridiculous rainfall totals. According to the most recent Public Information Statements from the NWS, the highest totals came from Schodack, NY (11.79″), Kinderhook, NY (11.47″), and Valatie, NY (10.31″).
All in all, this was a rather impressive rain event, especially considering the lack of a deep tropical moisture connection or direct tropical system impacts.
Tropics? Not here
The tropics are busy in the Pacific with the second category 5 storm of the week (Genevieve in the Eastern Pacific earlier this week was the other), this time in the West Pac. Super Typhoon Dolphin is back to category 4 intensity now, but it had peaked earlier today as a cat 5 storm.
A satellite view of a slightly disrupted Super Typhoon Dolphin in the Western Pacific. (Tropical Tidbits)
Dolphin is likely to head toward China or South Korea over the next week to 10 days.
Meanwhile, in the Atlantic, we got nuttin. Some of the AI modeling is trying to latch onto a weaker system in the deep Atlantic in about 10 days or so, but nothing suggests a likely storm, let alone a strong one. Something we’ll watch, but nothing we’re concerned with.
In brief: A potentially significant flash flooding event may unfold between the Hudson Valley and Philadelphia on Tuesday, with some uncertainty remaining on exactly who will see the most rain. Flood watches are posted.
Keeping the focus on the Northeast this evening, we are setting the stage for a potentially impactful day of flooding risk Tuesday from North Jersey, across New York City, and into southwest New England and southeast New York. The table was set today with some slow-moving torrential downpours in Rockland County, NY and Passaic and Bergen Counties in New Jersey.
Radar estimates of total rainfall through just before 7 PM ET on Monday. (WeatherFront)
Spring Valley, NY, just near the intersection of the Garden State Parkway and New York Thruway and Ridgewood in Bergen County, NJ seem to have seen the most rain with radar estimates around 3.5 inches.
We go through again this tomorrow but on a larger scale. The area was upgraded to a moderate risk of excessive rainfall (level 3/4) on Tuesday from northeast Jersey to just south of Albany.
(NOAA NWS)
Storms will move across the Poconos and Catskills in the late morning, spreading east through the afternoon. There’s some debate right now if storms will get going around early to mid afternoon or mid to late afternoon across the NYC Metro area. Some of the more recent high resolution model guidance seems to have slowed things down a bit in terms of the onset. But there is still some modeling that favors storms increasing pretty quickly tomorrow.
Either way, as the upper disturbance responsible for this mess closes off, the forward progress of rain will slow and more widespread rain will develop on the northern side of things. That’s why we could be talking about a radar image that looks similar to this tomorrow evening.
Forecast composite radar from HREF ensemble Tuesday evening. (WeatherFront)
In addition to this broad upper support for rain, there’s going to be an influx of moisture converging over New Jersey, New York, and New England.
Moisture converging over NJ, NY, and New England Tuesday evening. (Plymouth State University)
Whatever happens, there will likely be very heavy rain somewhere between Philly and Albany tomorrow afternoon and/or evening. There’s a pretty curiously high probability of risk of 5 inches or more of rainfall over 24 hours from the HREF model, which ensembles multiple high-resolution models.
Some parts of the Lower Hudson Valley are in the 70% or greater risk of 5 inches or more of rainfall through tomorrow night. (WeatherFront)
The Lower Hudson Valley seems to have the highest odds, but there are not so insignificant probabilities south of there toward Philadelphia or northern Delaware also. Extreme western Connecticut is also on the edge of these higher probabilities too.
While many parts of New Jersey have been dry, the area around New York City through southwest Connecticut has seen a lot of rain in the last 7 to 10 days and the onset of flash flooding may occur a bit faster than usual given these totals. Flood Watches are posted around this region, and folks should be prepared for a bit of a rough go of it tomorrow afternoon and evening.
Forecast NBM model rainfall through Thursday evening. (WeatherFront)
