2021 Global Model Runs Discussion (Out thru day 16)

[Kingarabian]

It's usually not a CAG if the area develops and establishes itself before interacting and lingering over CA. Looks too be associated with a TW currently near 40W-45W.

There it is.

https://i.imgur.com/Kon9u75.png

I just started a thread for it...

I know but I think the Mods might want a circle from the NHC first.

[Ivanhater]

There it is.

https://i.imgur.com/Kon9u75.png

I just started a thread for it...

I know but I think the Mods might want a circle from the NHC first.

This meets criteria one for starting a new thread. We just don't want to see a new thread everytime a model develops something.


1) There is an actual incipient area of disturbed weather already in place.
2) It is being mentioned in the NHC Tropical Weather Outlook.

[Kingarabian]

I just started a thread for it...

I know but I think the Mods might want a circle from the NHC first.

This meets criteria one for starting a new thread.


1) There is an actual incipient area of disturbed weather already in place.
2) It is being mentioned in the NHC Tropical Weather Outlook.

Got it thanks for the clarification!

[Ivanhater]

I know but I think the Mods might want a circle from the NHC first.

This meets criteria one for starting a new thread.


1) There is an actual incipient area of disturbed weather already in place.
2) It is being mentioned in the NHC Tropical Weather Outlook.

Got it thanks for the clarification!

No worries King!

[Category5Kaiju]

The GFS sure seems to want to latch onto the idea that by the very end of this month a TC forms from a CAG (or a wave that enters the WCAR) and develops it into something in the Gulf of Mexico (most recent run shows the Alabama/Florida border region get hit with a 980 mbar storm).

[Ubuntwo]

The GFS sure seems to want to latch onto the idea that by the very end of this month a TC forms from a CAG (or a wave that enters the WCAR) and develops it into something in the Gulf of Mexico (most recent run shows the Alabama/Florida border region get hit with a 980 mbar storm).

That looks to form from the wave currently around 45W, there's a thread up.

[Shell Mound]

I had to do a double take when I saw 973 mb over Martinque, like what. GFS Fantasy land in full swing, however what this tells me is to look for development in the MDR around that timeframe, have to just ignore the intensity for now cause...

The GFS is showing fantasies as is usual. It also showed 94L developing, only to fail miserably. I doubt that we’ll see anything in the MDR before August.

Would your forecast change if the MDR did ramp up before August? I recall you looking to see how MDR activity would take shape in the early months as a long term indicator.

Yes. If we were to see, say, one or more robust tropical storms (or stronger) in the MDR before August, I would be inclined to expect a very active season.

[Category5Kaiju]

And the GFS is trying to develop a solid TS in the WCAR by around July 7ish. Of course that is fantasy range, but assuming the GFS is indeed pretty good at sniffing the "big picture" atmospheric/oceanic conditions and actually is somewhat correct with this particular pattern, then this could certainly be something to watch.

[tolakram]

The GFS is showing fantasies as is usual. It also showed 94L developing, only to fail miserably. I doubt that we’ll see anything in the MDR before August.

Would your forecast change if the MDR did ramp up before August? I recall you looking to see how MDR activity would take shape in the early months as a long term indicator.

Yes. If we were to see, say, one or more robust tropical storms (or stronger) in the MDR before August, I would be inclined to expect a very active season.

I really don't understand why. Every season is unique and conditions are rarely static (2005 and 2013 are the outliers). Favorable conditions this week do not portend to favorable conditions a month from now, and vice versa. Anyone who's been around for a few years should know that those that predict an active season based on June and July activity are just as wrong as those who predict a dead season for the same reason.

[Blown Away]

(3) named systems by June 21 puts 2021 on track to be above average as predicted.

[Hypercane_Kyle]

Hard to get too worked up about the GFS scenario when there's zero model backing behind it. Does strike me as another ghost.

[Shell Mound]

Would your forecast change if the MDR did ramp up before August? I recall you looking to see how MDR activity would take shape in the early months as a long term indicator.

Yes. If we were to see, say, one or more robust tropical storms (or stronger) in the MDR before August, I would be inclined to expect a very active season.

I really don't understand why. ...

2021 doesn’t need to have a super early MDR hurricane like Beryl, but last year I went through every season from 1980 to present day and found a strong correlation between MDR or AEW-based storms/hurricanes in July and overall season activity. Accounting for 2020 (which had 3 AEW July systems, two of which became hurricanes), the average season numbers are:
—16.9 named storms
—9.0 hurricanes
—4.1 majors
—160.29 ACE

For seasons that had any non-AEW-based July system, even if they also had a tropical wave born system as well, the average is much lower:
—13.4 named storms
—6.6 hurricanes
—2.9 majors
—115.40 ACE

So yes, July activity is a very strong sign of what the rest of the season could be like. However, the fact that a lot of things are attempting to form this early does make the predictions for an above-average season more likely…unless there’s a sudden shift to +ENSO.

Source

[Blown Away]

Hard to get too worked up about the GFS scenario when there's zero model backing behind it. Does strike me as another ghost.

06 GFS has TS in Caribbean @8 days and then moves a Cat 2-3 into S Texas.

[Hypercane_Kyle]

Hard to get too worked up about the GFS scenario when there's zero model backing behind it. Does strike me as another ghost.

https://i.imgur.com/ZPm1KqW.gif
06 GFS has TS in Caribbean @8 days and then moves a Cat 2-3 into S Texas.

While not impossible, it's extraordinary rare to get that strong of a hurricane this early in the year in the Gulf. Alex in 2010 is the most recent example.

[OuterBanker]

Hard to get too worked up about the GFS scenario when there's zero model backing behind it. Does strike me as another ghost.

https://i.imgur.com/ZPm1KqW.gif
06 GFS has TS in Caribbean @8 days and then moves a Cat 2-3 into S Texas.

Typical long range windshield wiping from the GFS. Tx monster on Sat, Sun Tampa one run, panhandle the next. Back to Tx today.
At least it has let the east coast out of it

[aspen]

Yes. If we were to see, say, one or more robust tropical storms (or stronger) in the MDR before August, I would be inclined to expect a very active season.

I really don't understand why. ...

2021 doesn’t need to have a super early MDR hurricane like Beryl, but last year I went through every season from 1980 to present day and found a strong correlation between MDR or AEW-based storms/hurricanes in July and overall season activity. Accounting for 2020 (which had 3 AEW July systems, two of which became hurricanes), the average season numbers are:
—16.9 named storms
—9.0 hurricanes
—4.1 majors
—160.29 ACE

For seasons that had any non-AEW-based July system, even if they also had a tropical wave born system as well, the average is much lower:
—13.4 named storms
—6.6 hurricanes
—2.9 majors
—115.40 ACE

So yes, July activity is a very strong sign of what the rest of the season could be like. However, the fact that a lot of things are attempting to form this early does make the predictions for an above-average season more likely…unless there’s a sudden shift to +ENSO.

Source

There are two outliers I’d like to mention, thought: 2004 and 2013. The former barely counts as a year with an AEW-based July storm because Alex formed on July 31st (and it wasn’t solely from a wave but an AEW did contribute to its genesis), yet despite a late start, 2004 went one to be one of the most active and destructive seasons on record. 2013 had two AEW-born July systems — Chantal and Dorian — but ended up with the lowest ACE total in decades.

So while AEW-born July systems are good indicators for seasonal activity, like many indicators, things aren’t that simple and there are some exceptions. Still, even a weak MDR TS in late June would be quite the signal for activity by ASO, and an AEW-born hurricane between now and the first half of July would be too.

[Astromanía]

Hard to get too worked up about the GFS scenario when there's zero model backing behind it. Does strike me as another ghost.

https://i.imgur.com/ZPm1KqW.gif
06 GFS has TS in Caribbean @8 days and then moves a Cat 2-3 into S Texas.

While not impossible, it's extraordinary rare to get that strong of a hurricane this early in the year in the Gulf. Alex in 2010 is the most recent example.

Actually resembles the track a bit, just more north

[captainbarbossa19]

The windshield wiper continues. Now the GFS has landfall around Mobile again. At least it's not pushing back the formation time yet. It is still insisting that the wave east of the Caribbean will develop eventually. We will see.

[Steve]

The windshield wiper continues. Now the GFS has landfall around Mobile again. At least it's not pushing back the formation time yet. It is still insisting that the wave east of the Caribbean will develop eventually. We will see.

It would be end of next week/following weekend if so. CMC does spin something up in the EPAC prior to bulging up low pressure out of the western Caribbean. MJO looks to dawdle around in Phase 1 for the next few days. Nothing particularly amplified, but that's a favorable genesis phase, and if it were to swing through 2, that would be a decent advance indicator that we might get something to try to form.

[weeniepatrol]

 https://twitter.com/webberweather/status/1407067489545068545