OT: 2021 Tropical Weather Thread - A Busy Season Predicted and Observed

RU848789

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No idea what happened to the thread I posted on this back in June when all the seasonal forecasts came out, but fortunately (for maybe a few of you, lol), I post this stuff in multiple places, so below is what I posted back in early June; the subsequent posts on a bunch of tropical systems prior to Henri are gone, though. Obviously, we already have 13 named storms this season and we're only at the midway point of typical seasonal activity (Sept 10th), so odds are pretty high this season will be well above normal, unfortunately.

Post from June 4th 2021:

After last year's record smashing tropical season, featuring 30 named storms, 14 hurricanes and 7 major (cat 3 or higher) hurricanes, we could use a break this season, but today CSU (home of the late, great Dr. Gray, who pioneered seasonal tropical forecasting for the Atlantic Basin nearly 40 years ago) joined NOAA in predicting a moderately above average tropical season in the Atlantic this year. See the graphic below from the forecast issued today by CSU.

https://tropical.colostate.edu/Forecast/2021-06.pdf

Their prediction is for 18 named storms (14.4 avg), 8 hurricanes (7.2 avg) and 4 major hurricanes (3.2 avg), which doesn't sound that far above average until one realizes that they're comparing against the 30-year period from 1991-2020, which was a bit busier than the 1981-2010 period they've been comparing against for the last 10 years, where the seasonal average was 12.1 named storms, 6.4 hurricanes and 2.7 major hurricanes.

NOAA issued their forecast 2 weeks ago and it's fairly similar with somewhat above average numbers being predicted of 13-20 named storms 6-10 hurricanes and 3-5 major hurricanes; see graphic below. They do ranges, unlike CSU, but the midpoint of their ranges is very close to CSU's prediction, i.e., 16.5 named storms (18 from CSU), 8 hurricanes (8 from CS) and 4 major hurricanes (4 from CSU).

https://www.noaa.gov/.../noaa-predicts-another-active...

Both groups use much of the same combination of analog-based forecasts (looking back at key tropical indicators, like El Nino and tropical Atlantic sea surface temps for past seasons with similar indicators) and forward-looking dynamical/statistical global weather models and both cite the neutral ENSO (El Nino/Southern Oscillation indicator) state, where El Nino conditions inhibit tropical activity and current warmer-than-normal subtropical Atlantic SSTs as keys to their forecasts.

We'll see soon, but keep in mind that the CSU group has been far more accurate (near 70%) with their above normal, normal, below normal predictions than simple climatological guessing would be (1 in 3, on average, if guessing). We've had one minor tropical storm so far this season (Ana).

o8wEMZw.png


Jz2jotA.png
 
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e5fdny

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No.🙂

Storm/event = thread, a NEW one

Discussion = somewhere else

Guessing that’s where the thread went, somewhere else. 😉
 

RU848789

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No.🙂

Storm/event = thread, a NEW one

Discussion = somewhere else

Guessing that’s where the thread went, somewhere else. 😉
No, thread was deleted and never saw why (can see if they've been moved). Always had a thread for general activity with minor storms discussed and season progression and only separate threads for significant storms (those that would impact the US or any major hurricane that would make a landfall anywhere in the Atlantic Basin). 4Rreal used to usually start them with his contest, but he's "not here."
 

e5fdny

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No, thread was deleted and never saw why (can see if they've been moved). Always had a thread for general activity with minor storms discussed and season progression and only separate threads for significant storms (those that would impact the US or any major hurricane that would make a landfall anywhere in the Atlantic Basin). 4Rreal used to usually start them with his contest, but he's "not here."
Are you sure, like really sure?😛
 
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RU848789

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Tropical Storm Nicholas, which formed yesterday, is now bearing down on the central Texas coast, as it's currently just off the coast of Brownsville, heading north with an expected landfall near Port O'Connor TX this evening as a very strong tropical storm with winds of 70 mph (could even be a minimal cat 1 hurricane w/75 mph winds).

Some moderate to significant wind and storm surge damage are likely along the coast near and NE of landfall, but the biggest risk is torrential flooding rains (6-10" or more in spots) for large parts of Texas and Louisiana, both at the coast and well inland (including from Corpus Christi to Houston all the way to near New Orleans) over the next 2-3 days.

It being the peak of the tropical season, not surprisingly, there are two other threats out there. The first is a tropical wave east of the Bahamas, which could become a tropical storm and come uncomfortably close to the FL/GA/SC/NC coasts over the next several days, although it's more likely to stay off shore.

The second is a strong tropical wave just coming off the coast of Africa, south of the Cape Verde Islands (it is the Cape Verde part of the tropical season), which could develop into a hurricane traversing the Atlantic towards the Caribbean and then possibly threaten anywhere from the Caribbean to the Gulf to the US east coast (or become a fish storm out to sea - way, way, way too early to predict anything.

As per the last graphic below, this season is well above normal in almost every category, so far...

https://www.nhc.noaa.gov/

vXOy6po.png

AfsmSYv.png


u0wMct2.png



4gRPIx0.jpg
 
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e5fdny

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Could this affect our area or the Delaware game?
 

RU848789

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Tropical Storm Nicholas, which formed yesterday, is now bearing down on the central Texas coast, as it's currently just off the coast of Brownsville, heading north with an expected landfall near Port O'Connor TX this evening as a very strong tropical storm with winds of 70 mph (could even be a minimal cat 1 hurricane w/75 mph winds).

Some moderate to significant wind and storm surge damage are likely along the coast near and NE of landfall, but the biggest risk is torrential flooding rains (6-10" or more in spots) for large parts of Texas and Louisiana, both at the coast and well inland (including from Corpus Christi to Houston all the way to near New Orleans) over the next 2-3 days.

It being the peak of the tropical season, not surprisingly, there are two other threats out there. The first is a tropical wave east of the Bahamas, which could become a tropical storm and come uncomfortably close to the FL/GA/SC/NC coasts over the next several days, although it's more likely to stay off shore.

The second is a strong tropical wave just coming off the coast of Africa, south of the Cape Verde Islands (it is the Cape Verde part of the tropical season), which could develop into a hurricane traversing the Atlantic towards the Caribbean and then possibly threaten anywhere from the Caribbean to the Gulf to the US east coast (or become a fish storm out to sea - way, way, way too early to predict anything.

As per the last graphic below, this season is well above normal in almost every category, so far...

https://www.nhc.noaa.gov/

vXOy6po.png

AfsmSYv.png


u0wMct2.png



4gRPIx0.jpg

Nicholas just became a Cat 1 hurricane with 75 mph winds (measured 76 mph sustained and a gust to 97 mph in Matagordas TX), as it strengthened fairly rapidly this evening. Fortunately, more strengthening shouldn't occur as the storm should make landfall just NE of Matagordas in the next couple of hours.

As per this morning's post, the wind and storm surge risks are significant (but catastrophic damage should not occur), while the rainfall/flooding risk (both urban and stream/river flooding) along the TX/LA coasts and inland of there is substantial from the 4-8" of rain generally, given how saturated these areas are. The video below does a nice job of summarizing the storm's movement and impacts.


https://www.nhc.noaa.gov/refresh/graphics_at4+shtml/030938.shtml?cone#contents
 

RU848789

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Could this affect our area or the Delaware game?
Directly, as a tropical entity, no, as it will dissipate by mid-week. The moisture from Nicholas could end up feeding a tropical low which is likely to form off the FL/GA coast in a few days, and this is a small threat to our area on Fri/Sat, but so far models are showing this moisture staying offshore (but not that far away), as per the gameday weather thread - I assume you've seen it, lol...
 

RU848789

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Well, recently we had Odette, a weak tropical storm that harmlessly stayed off the east coast of the US last week, then we had Peter, another fairly weak tropical storm that came close to the Leeward Islands/Puerto Rico and turned NE eventually, becoming a fish storm until its demise yesterday, and then we had weak tropical storm Rose, which meandered around the far eastern Atlantic before its official demise this morning.

And now we have Sam, born yesterday in the central Atlantic, and predicted to become a major hurricane over the next couple of days, but fortunately forecast to bend north of the Caribbean/Islands and to head towards the general direction of Bermuda and will hopefully remain well offshore of the US east coast, as per the long range models, although it's too far out to predict that with certainty. It's the 2nd busiest tropical season in history, through this date...

https://www.nhc.noaa.gov/

dqDsavZ.png
 
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lloyde dobler

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Was there ever a time where a lot of the far off or weak storms like Peter or Rose were never monitored enough to be named?
 

Joey Bags

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Beware the modeled blocking high over canada. Still plenty of time to change but that is NOT the look you want if you live in the mid-atl and New England.
 

RU848789

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Was there ever a time where a lot of the far off or weak storms like Peter or Rose were never monitored enough to be named?
Peter and Rose? No, both existed for 5+ days, so even in the pre-satellite era, some ship would've encountered them and likely been able to provide wind speeds and other conditions reliably enough to name them tropical storms. There are, however, sometimes, 1-2 storms a year that are very short lived (1-2 days) and very remote, which might have escaped detection in the pre-satellite era - like subtropical storm Theresa, which was just named and will likely only last 24-36 hours north of Bermuda. Posted about this a couple of years ago, including links to an analysis of how often that likely would've happened, but that might be on the CE board now, which I don't have access to.

https://www.nhc.noaa.gov/graphics_at4.shtml?start#contents
 
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RU848789

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Beware the modeled blocking high over canada. Still plenty of time to change but that is NOT the look you want if you live in the mid-atl and New England.
Yes, there is a small risk that Sam could get shunted more westerly in about 7-8 days towards the US, but it's a low probability right now...
 

RU848789

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Well, recently we had Odette, a weak tropical storm that harmlessly stayed off the east coast of the US last week, then we had Peter, another fairly weak tropical storm that came close to the Leeward Islands/Puerto Rico and turned NE eventually, becoming a fish storm until its demise yesterday, and then we had weak tropical storm Rose, which meandered around the far eastern Atlantic before its official demise this morning.

And now we have Sam, born yesterday in the central Atlantic, and predicted to become a major hurricane over the next couple of days, but fortunately forecast to bend north of the Caribbean/Islands and to head towards the general direction of Bermuda and will hopefully remain well offshore of the US east coast, as per the long range models, although it's too far out to predict that with certainty. It's the 2nd busiest tropical season in history, through this date...

https://www.nhc.noaa.gov/

dqDsavZ.png

Wow, Sam has intensified explosively, from a 75 mph minimal hurricane 24 hours ago to a 120 mph Cat 3 monster as of 11 am - and Sam is likely up to 130-140 mph now, simply based on satellite presentation, with a nearly perfect eye and deep convection all around the system. Fortunately, Sam will miss the northernmost Leeward Islands by a decent amount, but could take a run at Bermuda. Sam also looks like it will it remain offshore beyond 5 days, possibly striking Newfoundland eventually. Still bears watching along the East Coast, though, in case things change (always possible beyond 5 days).

https://www.nhc.noaa.gov/graphics_at3.shtml?start#contents

9kw4T6u.png
 

RU848789

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Wow, Sam has intensified explosively, from a 75 mph minimal hurricane 24 hours ago to a 120 mph Cat 3 monster as of 11 am - and Sam is likely up to 130-140 mph now, simply based on satellite presentation, with a nearly perfect eye and deep convection all around the system. Fortunately, Sam will miss the northernmost Leeward Islands by a decent amount, but could take a run at Bermuda (probably as a Cat 3 by then). Sam also looks like it will it remain offshore beyond 5 days, possibly striking Newfoundland eventually. Still bears watching along the East Coast, though, in case things change (always possible beyond 5 days). The GIF, below, shows how nearly perfect Sam's eye, symmetry, and outflow are. Monster storm right now.

https://www.nhc.noaa.gov/graphics_at3.shtml?start#contents

9kw4T6u.png

As expected, Sam was up to 140 mph yesterday at 5 pm and is now up to 145 mph, a strong Cat 4 storm. Sam's forecast track takes the storm up towards Bermuda as a Cat 3 hurricane and then the long range models are all showing a track towards Newfoundland or east of there, staying well off the US east coast - still need to watch this one, though, in case the models are wrong. The GIF, below, shows how nearly perfect Sam's eye, symmetry, and outflow are. Monster storm right now.


https://www.nhc.noaa.gov/graphics_at3.shtml?start#contents

144800_5day_cone_with_line_and_wind.png


giphy.gif
 

RU848789

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As expected, major Hurricane Sam (Cat 4 with 130 mph winds) has turned NW-ward and should miss Bermuda by over 100 miles to the east of the island and will then start turning more NE-ward, becoming a "fish storm" - even Newfoundland looks to be just about in the clear now. In addition, the two potential tropical systems south of the Cape Verde Islands look like they will become tropical storms in the next day or two, but are likely to head into the Central Atlantic, not threatening any land. We can use the rest, lol.

https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=5

0crkYZL.png
 
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RU848789

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No idea what happened to the thread I posted on this back in June when all the seasonal forecasts came out, but fortunately (for maybe a few of you, lol), I post this stuff in multiple places, so below is what I posted back in early June; the subsequent posts on a bunch of tropical systems prior to Henri are gone, though. Obviously, we already have 13 named storms this season and we're only at the midway point of typical seasonal activity (Sept 10th), so odds are pretty high this season will be well above normal, unfortunately.

Post from June 4th 2021:

After last year's record smashing tropical season, featuring 30 named storms, 14 hurricanes and 7 major (cat 3 or higher) hurricanes, we could use a break this season, but today CSU (home of the late, great Dr. Gray, who pioneered seasonal tropical forecasting for the Atlantic Basin nearly 40 years ago) joined NOAA in predicting a moderately above average tropical season in the Atlantic this year. See the graphic below from the forecast issued today by CSU.

https://tropical.colostate.edu/Forecast/2021-06.pdf

Their prediction is for 18 named storms (14.4 avg), 8 hurricanes (7.2 avg) and 4 major hurricanes (3.2 avg), which doesn't sound that far above average until one realizes that they're comparing against the 30-year period from 1991-2020, which was a bit busier than the 1981-2010 period they've been comparing against for the last 10 years, where the seasonal average was 12.1 named storms, 6.4 hurricanes and 2.7 major hurricanes.

NOAA issued their forecast 2 weeks ago and it's fairly similar with somewhat above average numbers being predicted of 13-20 named storms 6-10 hurricanes and 3-5 major hurricanes; see graphic below. They do ranges, unlike CSU, but the midpoint of their ranges is very close to CSU's prediction, i.e., 16.5 named storms (18 from CSU), 8 hurricanes (8 from CS) and 4 major hurricanes (4 from CSU).

https://www.noaa.gov/.../noaa-predicts-another-active...

Both groups use much of the same combination of analog-based forecasts (looking back at key tropical indicators, like El Nino and tropical Atlantic sea surface temps for past seasons with similar indicators) and forward-looking dynamical/statistical global weather models and both cite the neutral ENSO (El Nino/Southern Oscillation indicator) state, where El Nino conditions inhibit tropical activity and current warmer-than-normal subtropical Atlantic SSTs as keys to their forecasts.

We'll see soon, but keep in mind that the CSU group has been far more accurate (near 70%) with their above normal, normal, below normal predictions than simple climatological guessing would be (1 in 3, on average, if guessing). We've had one minor tropical storm so far this season (Ana).

o8wEMZw.png


Jz2jotA.png

So, the tropical season is now officially over and it was quite an active one, as both CSU and NOAA predicted, with 21 named storms, 7 hurricanes and 4 major hurricanes. 2021 was the third most active year on record with regard to named storms and it marks the sixth consecutive above-normal Atlantic hurricane season; in addition, this was the first time on record that two consecutive hurricane seasons exhausted the list of 21 storm names. And, of course, there were eight US landfalling sysems, many with major impacts, including Henri and Ida with their tremendous flooding rains in our area.

https://www.noaa.gov/news-release/active-2021-atlantic-hurricane-season-officially-ends