2023 Atlantic Hurricane season

[GaWx]

 Similar to the 12Z UKMET, the 12Z Euro has a recurving TS well out in the MDR, which appears to be from the subsequent AEW to emerge from Africa in a few days rather than the one west of there.

[Ed, snow and hurricane fan]

Just now, GaWx said:

 Similar to the 12Z UKMET, the 12Z Euro has a recurving TS well out in the MDR, which appears to be from the subsequent AEW to emerge from Africa in a few days rather than the one east of there.

Recurvature seems to be a GFS ensemble trend as well for the members that develop a cyclone.  IMBYish, I'm wondering why various ensemble families seem to like the Caribbean/Gulf and SEUSA near/after 10 days.  Even if I reject the GFS Gulf ensemble members that develop a storm out of the SW Caribbean (coming of S America?) as a known GFS model family issue, Euro/CMC/GFS family all suggest something becomes more conducive to development in the W part of the basin.

[WxWatcher007]

1 hour ago, Ed, snow and hurricane fan said:

Recurvature seems to be a GFS ensemble trend as well for the members that develop a cyclone.  IMBYish, I'm wondering why various ensemble families seem to like the Caribbean/Gulf and SEUSA near/after 10 days.  Even if I reject the GFS Gulf ensemble members that develop a storm out of the SW Caribbean (coming of S America?) as a known GFS model family issue, Euro/CMC/GFS family all suggest something becomes more conducive to development in the W part of the basin.

https://x.com/tropicaltidbits/status/1690795984283127808?s=46&t=Nn9Cx92_8118fPdhHPdJHw

 

[WxWatcher007]

Do tweets not auto embed anymore?

[GaWx]

 On the 12Z EPS through 240, I counted 15 Hs (30% of members) at a minimum from just the wave now in the E MDR. There's something like 30 members from all of the waves, combined, with a H. There still are four different possibilities to watch during the next ten days.

[ldub23]

1 hour ago, GaWx said:

 On the 12Z EPS through 240, I counted 15 Hs (30% of members) at a minimum from just the wave now in the E MDR. There's something like 30 members from all of the waves, combined, with a H. There still are four different possibilities to watch during the next ten days.

First  hint the GFS might  be starting the season

 

 

 

 

 

 

 

 

 

 

 

 

For the first time it  shows  something  developing  behind the cane  hitting TX which could  indicate a  pattern change

 

But then it shows a  second  low  forming  in the west  gom

[ldub23]

Just now, ldub23 said:

First  hint the GFS might  be starting the season

 

 

 

 

 

 

 

 

 

 

 

 

For the first time it  shows  something  developing  behind the cane  hitting TX which could  indicate a  pattern change

 

But then it shows a  second  low  forming  in the west  gom

read  fast

[Ed, snow and hurricane fan]

1 minute ago, ldub23 said:

read  fast

As a rule, play by play at hour 300 on the GFS isn't probably needed.  If those are still here in ten days, model run play by play, New England forum snowstorm style where people note the 200 mb jet streak over Minnesota is deeper than the prior run, that is coo..

[WxWatcher007]

GFS showing robust waves and opportunities for TC genesis inside a week is all I need to see. Increasing signal the the basin rises (somewhat) from the dead in the next week. Big test for the basin. 

[WxWatcher007]

Two lemons now.

[GaWx]

GFS runs since 7/31 with hurricane: 3 of last 4

-7/31 12Z: hit SC 8/16
-8/3 6Z: hit MX/TX border 8/16
-8/6 0Z: MDR 8/18-21
-8/9 18Z: just off SC 8/25
-8/11 0Z: GOM just off LA 8/26
-8/13 0Z: GOM 8/26-8
-8/13 6Z: GOM 8/25-6 that hits MS 8/26-7.  
-8/13 18Z: GOM 8/25 hits S TX 8/26

[Ed, snow and hurricane fan]

Ballpark 60% of the ensembles at this time have a TC in the Gulf or off SEUSA, looks like about 40% of Euro ensembles have a one.  18Z Euro ensembles, about half of the members have the first wave off Africa as a TC next Saturday, with the weaker members entering the Caribbean, the stronger passing N of the Caribbean.  Or, I say a coin flip we have at least one TC by early next week.  If Euro ensembles are correct, NHC's lemon bubble may be oriented to much from SSE to NNW, when the ensembles are closer to E to W

[GaWx]

12 hours ago, GaWx said:

For the first time recently, the UKMET has Atlantic TCG (favoring recurving from the MDR):

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS
FORECAST POSITION AT T+138 : 16.7N 42.6W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 19.08.2023 144 16.8N 42.7W 1009 29
0000UTC 20.08.2023 156 17.1N 43.1W 1008 31
1200UTC 20.08.2023 168 17.8N 43.8W 1007 33

0Z UKMET develops a wave behind the one that the 12Z developed and at a lower latitude while moving it WNW:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 162 HOURS
FORECAST POSITION AT T+162 : 12.0N 20.4W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 21.08.2023 168 12.7N 22.3W 1009 24

[shaggy]

A lot more noise on 06z gfs op and the gefs so far this morning

[nwohweather]

Another season of a quiet August 

[GaWx]

1 hour ago, nwohweather said:

Another season of a quiet August 

A quiet first half of August for sure but the second half is looking to be much more active per model consensus. The consensus looks nothing like the dead model consensus from one year ago at this time. There are as of now at least four second half of August possibilities per models. I'm sticking with 2-3 named storms from these at this point and even can't eliminate the chance for four.

[Normandy]

Agree the pot is getting hot and storms are going to form soon.  Not seeing an august shut out at all based on current modeling.  Even a look at satellite one can see very discernible waves / future lows in the gulf and near the Bahamas.  

[Kevin Reilly]

59 minutes ago, Normandy said:

Agree the pot is getting hot and storms are going to form soon.  Not seeing an august shut out at all based on current modeling.  Even a look at satellite one can see very discernible waves / future lows in the gulf and near the Bahamas.  

There appears to even be a weak low now off the west coast pf Florida not far off of Sarasota too much shear from the Northeast at the moment. 

[nwohweather]

1 hour ago, GaWx said:

A quiet first half of August for sure but the second half is looking to be much more active per model consensus. The consensus looks nothing like the dead model consensus from one year ago at this time. There are as of now at least four second half of August possibilities per models. I'm sticking with 2-3 named storms from these at this point and even can't eliminate the chance for four.

As long as you have all that saharan dust out there, I don't care what any model shows

[ldub23]

12 minutes ago, nwohweather said:

As long as you have all that saharan dust out there, I don't care what any model shows

GFS has a  cane  in the GOM but  it  seems highly  unlikely that  will happen. At  216 is where it  begins  but what actually  will happen is it develops  in the east  pac. The  pattern hasnt  changed  1 iota because there  is  nothing  behind  it  developing. 0/0 Aug thru aug  30 on the GFS now except  for  an unlikely  GOM cane. I think the GFS is  confusing the Colombian heat  low that  is  hostile for  development  for an actual disturbance. Another argument against development  is that huge front  blasting  off the east  coast. As  i often say if you want to see west carib/gom development you want a  locked  and  loaded high dominating the west ATL. Since  its  peak and something should  be  happening  i give  it  a  1% chance. Only a  99% chance  it  doesnt develop

 

[GaWx]

27 minutes ago, nwohweather said:

As long as you have all that saharan dust out there, I don't care what any model shows

-You may end up right as nobody knows. It won't upset me at all if you end up being correct. But I just don't think you'll be right.
-I'm aware of the dust but aren't the models?
-Will the widespread dust last through the end of the month?
-Are there development areas of the basin that won't have much dust for much longer? What about the GOM, for example?...

-As usual, lots of uncertainty which makes these forecasting discussions that much more interesting. Without the uncertainty, it would be pretty boring as there'd be no challenge to forecast and thus no debates.

-Edit: For the first time in 3 runs, the UKMET has no TCG over its 7 day forecast period. However, the best chances for TCG are in week two imo. Also, the UKMET tends to be conservative.

 

[NorthHillsWx]

Crazy watching these powerful waves just evaporate over the MDR on modeling in peak season. Ensemble support had definitely increased and (we are in peak season now) the threat level is higher than it was a couple weeks ago but a couple of limiting factors remain:

1) SAL - this *should* follow climo and become less of a factor over the next few weeks but it is a dessert across most of the Atlantic 

2) East coast trough - this has been mentioned on here but a few thoughts: with a persistent trough over the east coast we are seeing more intrusions of continental dry air into the GOM, a TUTT over the western Atlantic, and a natural barrier to storms forming east favoring recurves. With the trough in place and the possibility more fronts make it to the gulf or SE coast to rot, that could be a focal point for development at some point but currently there is too much shear for that to happen.

3) subsidence off the African coast - this is something to watch and we saw this a lot last august, but these massive waves seem to blow up over the continent and die over water. I can’t blame SAL for this entirely. It seems the current pattern has created an area of subsidence near the CV islands. Perhaps it’s the wave interaction with the strong monsoon trough but it’s been a wave killer for MDR storms two years in a row. That’s something I’d like to see examined as a case study for impacts to East Atlantic waves stemming from a long period La Niña 

4) hostile Caribbean - very normal for early season but should be transitioning to a more favorable environment by now. This is where El Niño impacts will be seen the strongest. While current shear conditions across the area are not necessarily related to an El Niño pattern, will there be a period when it becomes favorable before the shear due to ENSO arrives? An active E PAC usually shuts down the Caribbean and brings me to me last observation…

5) Active E PAC - we all know an active E PAC does not favor development in the western Atlantic. With the E PAC season ramping up, does that further punt the start of the western Atlantic/GOM/Caribbean season? 

[WxWatcher007]

Good stuff in here the last few days. Still not sure where I’m going to go with my peak forecast but I lean slightly BN.

[Ed, snow and hurricane fan]

HRD scientist doesn't seem to buy the development approaching 60W in 6 days on the ensembles.  Nor does NHC, apparently.

 

 

[jconsor]

 

[jconsor]

I am skeptical of the idea that the main period of favorability for Atlantic TC development will be compressed into a week to 10 day period at the end of Aug/very beginning of Sep, like some extended guidance is hinting at.  Overall, there are indications of a more active than usual September. I explain why in the thread below:
 

 

[tiger_deF]

The wave moving off of Africa right now is quite impressive. How it develops (or fails to) and how it interacts with the wave in the Central Atlantic to the left will be interesting to watch over the next few days.

[GaWx]

GFS 12 runs out of 63 since 7/31 with hurricane (7 of them over last 11 runs)(last 9 H within 8/25-30):

-7/31 12Z: hit SC 8/16
-8/3 6Z: GOM hit MX/TX border 8/16
-8/6 0Z: MDR 8/18-21
-8/9 18Z: just off SC 8/25
-8/11 0Z: GOM just off LA 8/26
-8/13 0Z: GOM 8/26-8
-8/13 6Z: GOM 8/25-6 that hits MS 8/26-7. 
-8/13 18Z: GOM 8/25 hits S TX 8/26
-8/14 0Z : off SC/NC 8/26-29
-8/14 6Z: off NC 8/28-30
-8/14 12Z: GOM 8/27 hits LA 8/28
-8/15 6Z: GOM 8/26 hits FL Panhandle 8/27

[ldub23]

16 minutes ago, GaWx said:

GFS 12 runs out of 63 since 7/31 with hurricane (7 of them over last 11 runs)(last 9 H within 8/25-30):

-7/31 12Z: hit SC 8/16
-8/3 6Z: GOM hit MX/TX border 8/16
-8/6 0Z: MDR 8/18-21
-8/9 18Z: just off SC 8/25
-8/11 0Z: GOM just off LA 8/26
-8/13 0Z: GOM 8/26-8
-8/13 6Z: GOM 8/25-6 that hits MS 8/26-7. 
-8/13 18Z: GOM 8/25 hits S TX 8/26
-8/14 0Z : off SC/NC 8/26-29
-8/14 6Z: off NC 8/28-30
-8/14 12Z: GOM 8/27 hits LA 8/28
-8/15 6Z: GOM 8/26 hits FL Panhandle 8/27

All i see  is a weak broad  low  in the west  GOM. No hurricane anywhere thru aug 31.

 

[GaWx]

48 minutes ago, ldub23 said:

All i see  is a weak broad  low  in the west  GOM. No hurricane anywhere thru aug 31.

 

Yes, the 12Z GFS has no H. The last on the list with a H is the 6Z GFS.

 Meanwhile:

Some pretty significant model news since the UKMET tends to be conservative: 

-The 12Z UKMET has TCG from the westernmost lemon in the W MDR on Fri (8/18) and it then hits the Leewards as a TS late on Saturday (8/19). 
-It then moves WNW to Hispaniola on Mon (8/21) still as a TS
-It ends up near SE Bahamas as a slowly strengthening TS on Tue (8/22) moving slowly WNW and in a potentially threatening position to the Bahamas/SE US.

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 78 HOURS
FORECAST POSITION AT T+ 78 : 14.2N 51.4W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 19.08.2023 84 14.7N 53.5W 1005 30
1200UTC 19.08.2023 96 15.4N 57.4W 1004 34
0000UTC 20.08.2023 108 16.3N 60.5W 1003 37
1200UTC 20.08.2023 120 17.5N 63.5W 1004 40
0000UTC 21.08.2023 132 17.8N 67.0W 1004 37
1200UTC 21.08.2023 144 19.4N 68.7W 1004 38
0000UTC 22.08.2023 156 20.3N 71.2W 1004 37
1200UTC 22.08.2023 168 21.0N 72.9W 1003 39

 

Edit: But the 12Z Euro like the GFS has just about nothing.