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19-09-2020, 11:34   #211
Gaoth Laidir
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Tropical Storm Beta has been named in the western Gulf overnight and it may reach hurricane status before making landfall somewhere along the southwestern Texas coast. It looks like it could skirt up along the coast for the next few days, but forecast confidence is very low and this map could completely change again.

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INIT 19/0900Z 26.0N 92.5W 50 KT 60 MPH
12H 19/1800Z 26.6N 92.6W 55 KT 65 MPH
24H 20/0600Z 26.9N 93.4W 60 KT 70 MPH
36H 20/1800Z 27.1N 94.3W 65 KT 75 MPH
48H 21/0600Z 27.4N 95.2W 70 KT 80 MPH
60H 21/1800Z 27.7N 95.9W 70 KT 80 MPH
72H 22/0600Z 28.1N 96.3W 65 KT 75 MPH
96H 23/0600Z 28.7N 95.4W 60 KT 70 MPH
120H 24/0600Z 29.7N 93.3W 50 KT 60 MPH
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19-09-2020, 11:46   #212
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Teddy has weakened slightly to 110 knots as it goes through an ERC and it should start to slowly weaken overnight as it moves well to the east of Bermuda on Monday and towards Nova Scotia on Wednesday, by which time it should be below hurricane strength and going through extratropical transition.

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19-09-2020, 16:38   #213
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Looks like Bermuda is going to get very lucky. Teddy's weakening just before it hit was always forecast but now should miss them altogether.

Meanwhile, poor Louisiana. One state getting whacked a third time in month along with Texas this go.
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19-09-2020, 22:59   #214
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Nice chart shows the cold upwelling that the various storms have generated over the past 7 days. Most notable are the tracks of Paulette, which turned northeastwards around Bermuda, with Teddy following roughly the same path up to now. Also just off the New Orleans coast, where Sally moved slowly.

Tropical cyclones are efficient heat-transfer machines, from the water to the atmosphere and then out to space.

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20-09-2020, 12:13   #215
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Tropical Storm Beta is southeast of Galveston now and will slowly move northwestwards towards the mid-Texas coast, landfalling somewhere around Port O'Connor as a50-knot TS late tomorrow. Its structure has diminished due to shear and dry air wrapping around from the west, and the 50-knot winds are actually along a cold frontal zone well to the northeast of the centre.

Live centre fixes map


Latest 37 GHz
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20-09-2020, 12:20   #216
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Teddy is now 100 knots and feeling effects of shear and dry air. It will continue to slowly weaken as it passes east of Bermuda early tomorrow and then accelerate towards Nova Scotia and New Foundland, becoming extratropical as it does so.



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20-09-2020, 12:28   #217
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The latest aircraft recon into Teddy has only found max SFMR winds of 73 knots, max fligh level winds of 88 knots.

Quote:
355
URNT12 KNHC 201050
VORTEX DATA MESSAGE AL202020
A. 20/10:33:20Z
B. 27.92 deg N 062.51 deg W
C. 700 mb 2784 m
D. 964 mb
E. 200 deg 3 kt
F. OPEN SW
G. C40
H. 55 kt
I. 224 deg 23 nm 10:26:30Z
J. 329 deg 70 kt
K. 231 deg 33 nm 10:23:30Z
L. 73 kt
M. 047 deg 28 nm 10:42:00Z

N. 138 deg 88 kt
O. 047 deg 34 nm 10:43:30Z

P. 11 C / 3049 m
Q. 16 C / 3051 m
R. 13 C / NA
S. 12345 / 7
T. 0.02 / 2 nm
U. AF307 0520A TEDDY OB 05
MAX FL WIND 88 KT 047 / 34 NM 10:43:30Z
Live recon chart



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21-09-2020, 13:16   #218
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Nova Scotia seems to have dodged a bullet, it was looking a lot stronger as it made landfall there just a couple of days ago model-wise
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21-09-2020, 16:32   #219
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Quote:
Originally Posted by hatrickpatrick View Post
Nova Scotia seems to have dodged a bullet, it was looking a lot stronger as it made landfall there just a couple of days ago model-wise
The NHC were consistently going on the top end or above the model guidance (with the exception of the NGVI, which for some reason has gone bonkers on the intensities this year and seems to be always an upper outlier). Teddy managed to get it together for a little while but again, like pretty much all the other systems this year (bar Laura), it struggled with shear or dry air for a lot of the time.

Of the 23 named systems this season only nine have reached intensities above 50 knots, and of these only two got above 100 knots (Teddy, 120 kt and Laura, 130 kt). The current stats of Named storms/Hurricanes/Major hurricanes/Total ACE stand at 23/8/2/99.4, compared to the 1981-2010 average for this point in the season of 8.0/3.9/1.9/70.1.

We should see a quiet period set in now as the MJO is weak and in Phase 4 and a Kelvin wave suppresses Atlantic convection. With Beta about to make landfall as a weak tropical storm tonight 2020 will tie with 1916 for the highest number of landfalling systems in one season (9). With all that we're hearing it's amazing to hear that we were seeing similar activity back over 100 years ago. Will CNN report that, I wonder?

https://twitter.com/philklotzbach/st...14269670203394

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21-09-2020, 22:11   #220
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Beta is just making landfall along the mid-Texas coast but there's no real structure to it on radar. Max surface wind reports in the 20-25-knot range.

It should just make it inland before moving northeastwards along the coast over the next couple of days.

Wind gusts (red) below are in mph.

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Last edited by Gaoth Laidir; 21-09-2020 at 22:14.
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24-09-2020, 19:39   #221
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Quote:
Originally Posted by Gaoth Laidir View Post
2020 will tie with 1916 for the highest number of landfalling systems in one season (9). With all that we're hearing it's amazing to hear that we were seeing similar activity back over 100 years ago. Will CNN report that, I wonder?
Slightly off-topic, but I will forever be fascinated and mystified by the 1933 Atlantic Season, which actually surpassed 2005 in terms of ACE and in my opinion almost certainly had far more name-worthy storms than its official tally, given that it occurred before satellites and therefore would have missed a huge number of recurving fish storms.

I would love to get my hands on the kind of teleconnection data we have access to now (global SST anomalies, SAL analyses, wind shear etc) to compare the 1933 season with 2005, 2017 and 2020, as I'm very much convinced that there are as-yet undiscovered teleconnections which make hurricane seasons more or less active, beyond the well known markers such as ENSO, PDO, AMO, IOD etc.

2005, for example, did not feature a La Nina event but featured a prolonged period of severely curtailed convection in the Central Pacific, almost like a season-long standing wave of subsidence and an equivalent standing wave of enhancement over the Atlantic. None of the obvious teleconnections account for what might cause these conditions and obviously for 1933 there just isn't enough data, but it raises the possibility that there are other processes involved which we don't understand yet, and I for one can't get enough of that kind of thing

EDIT: To give one simple example: Do we know what caused the African Easterly Jet to slow to a crawl during peak season, such that tropical waves got stuck in the East Atlantic and moved far too slowly to develop? And could this have been predicted ahead of time? It seems to have caught every forecasting agency and meteorologist off guard. The wave which became Paulette, for instance, seemed to take forever to actually make it into the Atlantic after the NHC tagged it as an invest inland over Africa and even then it crawled along for the first few days.

Last edited by hatrickpatrick; 24-09-2020 at 19:43.
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24-09-2020, 19:53   #222
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Quote:
Originally Posted by hatrickpatrick View Post
Slightly off-topic, but I will forever be fascinated and mystified by the 1933 Atlantic Season, which actually surpassed 2005 in terms of ACE and in my opinion almost certainly had far more name-worthy storms than its official tally, given that it occurred before satellites and therefore would have missed a huge number of recurving fish storms.

I would love to get my hands on the kind of teleconnection data we have access to now (global SST anomalies, SAL analyses, wind shear etc) to compare the 1933 season with 2005, 2017 and 2020, as I'm very much convinced that there are as-yet undiscovered teleconnections which make hurricane seasons more or less active, beyond the well known markers such as ENSO, PDO, AMO, IOD etc.

2005, for example, did not feature a La Nina event but featured a prolonged period of severely curtailed convection in the Central Pacific, almost like a season-long standing wave of subsidence and an equivalent standing wave of enhancement over the Atlantic. None of the obvious teleconnections account for what might cause these conditions and obviously for 1933 there just isn't enough data, but it raises the possibility that there are other processes involved which we don't understand yet, and I for one can't get enough of that kind of thing

EDIT: To give one simple example: Do we know what caused the African Easterly Jet to slow to a crawl during peak season, such that tropical waves got stuck in the East Atlantic and moved far too slowly to develop? And could this have been predicted ahead of time? It seems to have caught every forecasting agency and meteorologist off guard. The wave which became Paulette, for instance, seemed to take forever to actually make it into the Atlantic after the NHC tagged it as an invest inland over Africa and even then it crawled along for the first few days.
Totally agree. Many other years make the top 10 when you look at ACE and Major Hurricanes. There will most certainly have been many systems missed, and yet the number of recorded systems is still very close to years in the satellite era. Below is list sorted by Major Hurricane Days, but it's a similar picture sorted by several other parameters too, with 1893, 1926, 1950, 1961, etc. also making the top 10.

All we know is that there is so much that we still don't know.

http://tropical.atmos.colostate.edu/...=northatlantic

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24-09-2020, 20:10   #223
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The Atlantic has gone dead quiet now, with no systems currently active or expected in at least the next 5 days. This is most likely due to the combination of the Phase 4 MJO and a CC Kelvin wave suppressing convection in the Atlantic basin.

Here are the global stats as they stand. The active Atlantic has had 23 named storms, but only 9 of which made it above 50 knots and only two above 100 knots. Still a very low percentage of major hurricanes. Elsewhere, it's been a very quiet Pacific, making the northern hemisphere as a whole only 68% of the average ACE for this point of the season.

The combination of the negative Indian Ocean Dipole and La Nina should bring an early start to what should be an active Australian rainy season, so we could see the southeastern Indian Ocean and SW Pacific perk up in a few months.

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02-10-2020, 16:11   #224
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TD Twenty Five has formed in the Caribbean.

Quote:
Tropical Depression Twenty-Five Discussion Number 1
NWS National Hurricane Center Miami FL AL252020
1100 AM EDT Fri Oct 02 2020

Visible satellite images show that cloudiness and showers associated with the low pressure area over the northwestern Caribbean Sea have
become significantly better organized since yesterday, with convective banding features becoming prominent. Moreover, low cloud
motions suggest that a closed circulation has become better defined. Therefore, advisories are being initiated on Tropical Depression
Twenty-Five at this time. The initial intensity estimate is 30 kt based on Dvorak T-numbers, but an Air Force Reserve Hurricane Hunter
aircraft is scheduled to investigate the system later today to provide a better intensity estimate. Sea surface temperatures are
very warm, near 30 deg C, and vertical shear should remain low for at least the next couple of days, so the cyclone is likely to become
a tropical storm by the time it nears the Yucatan Peninsula tomorrow. The main impediment to strengthening over the next few
days should be the interaction with land. Given the uncertainties about how far offshore the center will be over the next several
days, the official intensity forecast is conservative.

Since there is still a lot of scatter in the center fixes, the initial motion estimate, 315/8 kt, is rather uncertain. For the
next couple of days, the system is expected to move northwestward to north-northwestward on the southwestern edge of a mid-level high
pressure area. This would take the center near or over the northeastern Yucatan Peninsula. After about 48 hours, the steering
currents are not well-defined and there is considerable spread in the track models. At this time, it appears the cyclone should move
slowly westward over the latter part of the forecast period in response to weak ridging over the north-central Gulf of Mexico. The
official forecast is near or a little north of the corrected and simple model consensus predictions.

Tropical Storm Warnings and Watches have been issued for a portion
of the Yucatan Peninsula.

KEY MESSAGES:

1. The system is expected to produce heavy rainfall that could result in life-threatening flash flooding over portions of the
Yucatan Peninsula, far western Cuba and well away from the center in the Mexican states of Campeche, Tabasco, and northern Chiapas.

2. The depression is forecast to become a tropical storm and bring tropical storm conditions to portions of the Yucatan Peninsula on
Saturday, where a Tropical Storm Warning is in effect.

FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 18.1N 84.7W 30 KT 35 MPH
12H 03/0000Z 18.9N 85.6W 30 KT 35 MPH
24H 03/1200Z 19.8N 86.6W 35 KT 40 MPH
36H 04/0000Z 20.6N 87.2W 40 KT 45 MPH...INLAND
48H 04/1200Z 21.4N 87.5W 40 KT 45 MPH...INLAND
60H 05/0000Z 22.0N 87.6W 40 KT 45 MPH
72H 05/1200Z 22.0N 88.2W 45 KT 50 MPH
96H 06/1200Z 21.5N 90.5W 45 KT 50 MPH
120H 07/1200Z 21.5N 92.5W 45 KT 50 MPH


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03-10-2020, 01:20   #225
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Twenty Five has just become Tropical Storm Gamma.

Quote:
ULLETIN
Tropical Storm Gamma Intermediate Advisory Number 2A
NWS National Hurricane Center Miami FL AL252020
700 PM CDT Fri Oct 02 2020

...DEPRESSION BECOMES TROPICAL STORM GAMMA OVER THE NORTHWESTERN
CARIBBEAN SEA...


SUMMARY OF 700 PM CDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...18.8N 85.8W
ABOUT 135 MI...220 KM SSE OF COZUMEL MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES
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