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Tropical 2024 Tropical Thread Reboot

Snowfan said:
Northwestern Caribbean Sea and Gulf of Mexico:
A broad area of low pressure should form during the next few days
over the northwestern Caribbean Sea and the adjacent portions of
Central America. Thereafter, gradual development of this system is
expected, and a tropical depression is likely to form as the system
moves slowly northward across the northwestern Caribbean Sea and
Gulf of Mexico through the end of next week. Regardless of
development, this system is expected to produce heavy rains over
portions of Central America during the next several days.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...high...70 percent.
Click to expand...
Circle stayed the same....

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More from LC

From an outside glance, it might seem to be an ideal autumn forecast. The only cold air in the Northern Hemisphere is close to the North Pole. There are no named storms in the Atlantic Basin, and the still mostly stable, warm atmosphere in the USA argues against much chance for severe weather. But that "calm before the storm" sense is prevalent here, since disturbances are noted in that warm water space between North America and Africa, and I am confident the main threat zones will be the major islands and nations that rim the Caribbean Sea. Even with "Cape Verde" season likely to shut down in mid-October (westerly winds aloft becoming prevalent, with decreased shear), the western half of the basin will activate through dessicated frontal structures, warmed TUTT signatures, and MCS transitions. That may mean some major hurricanes, and I would look heavily at Central America or the Greater Antilles. Of course, any storm that does form most likely would head in the direction of the Eastern Seaboard.

Cold air potential sometimes bumps up in October, but I see nothing in the modeled forecasts that would imply any colder turns in the lower 48 states before Halloween. With a building Gulf of Alaska vortex, the semizonal jet stream will descend only slowly in latitude. Temperatures would slowly come down across Canada. The chance for a major severe weather threat will increase during the second half of next month, which fits well with La Nina climatology. The issue we have to worry about is if that rare cold intrusion interacts with a stronger tropical cyclone in the days before Halloween, the Mid-Atlantic and New England would be especially vulnerable. A different problem to look at is if a stronger hurricane were to develop, the risk of the system stalling (troughs will not reach into the Caribbean Sea) near Central America or one of the major islands could mean torrential rain.
 
The latest Euro Weeklies mean went absolutely bonkers for the week of 10/7-13. It has a whopping 340% of 2004-2023 averaged ACE or ~23! (see top image below). This is well over peak week climo of 16, which is 4 weeks earlier! This is easily the single highest week I could recall for any single week of Euro Weeklies for the season to date! The 2nd image shows where the bulk of the activity is expected: Gulf, N Caribbean, Bahamas, Bermuda, and much of the W and C subtropical Atlantic.


Going back to 1991, I could find only two seasons with ACE anywhere close to 23 during Oct 7-13:

-2018’s ~24 due mainly to Leslie and Michael

-2016’s ~18 due to Matthew and Nicole

So, the latest Weeklies are calling for Oct 7-13 to be just about tied with 2018 for the most active since 1991. That’s very notable for a 100 member ensemble mean.

In addition the run’s mean for the week prior, 9/30-10/6 is at 180% of 20 year climo or 17. So, after Helene gets ACE and the E MDR get ACE up to ~75, an additional 40 is progged for the subsequent two weeks. That would bring ACE up to ~115 with the last half of Oct and Nov still left. The same run is progging another 15 for 10/14-27, which would get it to 130. If this were to verify closely, a 150ish total season ACE would not be far fetched considering the warmth of the Atlantic and the strengthening Niña.

IMG_0298.png

IMG_0299.png
 
GaWx said:
The latest Euro Weeklies mean went absolutely bonkers for the week of 10/7-13. It has a whopping 340% of 2004-2023 averaged ACE or ~23! (see top image below). This is well over peak week climo of 16, which is 4 weeks earlier! This is easily the single highest week I could recall for any single week of Euro Weeklies for the season to date! The 2nd image shows where the bulk of the activity is expected: Gulf, N Caribbean, Bahamas, Bermuda, and much of the W and C subtropical Atlantic.


Going back to 1991, I could find only two seasons with ACE anywhere close to 23 during Oct 7-13:

-2018’s ~24 due mainly to Leslie and Michael

-2016’s ~18 due to Matthew and Nicole

So, the latest Weeklies are calling for Oct 7-13 to be just about tied with 2018 for the most active since 1991. That’s very notable for a 100 member ensemble mean.

In addition the run’s mean for the week prior, 9/30-10/6 is at 180% of 20 year climo or 17. So, after Helene gets ACE and the E MDR get ACE up to ~75, an additional 40 is progged for the subsequent two weeks. That would bring ACE up to ~115 with the last half of Oct and Nov still left. The same run is progging another 15 for 10/14-27, which would get it to 130. If this were to verify closely, a 150ish total season ACE would not be far fetched considering the warmth of the Atlantic and the strengthening Niña.

View attachment 151723

View attachment 151724
Click to expand...
GFS goes bonkers

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