2023 Atlantic Hurricane season

[GaWx]

The last several days of the admittedly inferior quality CFS have been taking energy coming off Africa about now and having it early next week collide with energy now WSW of the CV Islands. It subsequently has TCG in the MDR. The TC ends up threatening the SE US at midmonth. On these CFS runs, that has been the most threatening system of the entire month to the SE US. But again, the CFS is relatively inferior. So, this is fwiw, which may not be much. But it does have the last few CMC/GEPS in pretty good agreement along with the last few ICON and JMA runs to an extent.

[GaWx]

Based on the 12Z model consensus, my biggest concern for at least the next two weeks for the CONUS is for the period August 13-17, when the Bermuda high/WAR looks strongest, which may make it hard for a safe recurve. During that period, the model/ensemble consensus is suggesting that what's now coming off Africa will merge with energy/moisture now near 30-35W and likely move quite far west in the MDR at a very much up in the air strength (could end up being just a vigorous tropical wave). Bears watching.

[ldub23]

11 hours ago, GaWx said:

Based on the 12Z model consensus, my biggest concern for at least the next two weeks for the CONUS is for the period August 13-17, when the Bermuda high/WAR looks strongest, which may make it hard for a safe recurve. During that period, the model/ensemble consensus is suggesting that what's now coming off Africa will merge with energy/moisture now near 30-35W and likely move quite far west in the MDR at a very much up in the air strength (could end up being just a vigorous tropical wave). Bears watching.

JB agrees

 

 

The American Storm

 

@BigJoeBastardi

·

35m

 

First wave and threat to the US looks to be about 10 days off. at 500 mb pattern the period Aug 20-30 looks to be very close to analogs of major hits from 2003-2022. Painstakingly went over every map to come up for analog Euro has enhanced eastern threat day 11-18

[Floydbuster]

The GEFS has continued to show a powerful South Texas landfall in some runs. Other runs show the SE U.S.

 

[Ed, snow and hurricane fan]

The op Euro is well supported by its ensembles (and has less smoothing than a mean at 10 days).  If there is something there, there will be a US landfall threat.  There are some storms on the GFS and Euro ensembles, but not enough to convince me there is more than a low chance of a TC occurring with no operational support when the pattern favors US landfall.

Maybe OT, looking at ensemble chi forecasts, and the Canadian, GFS and Euro forecasts are rather divergent.  Canadian has pretty decent upward forcing around this time the other models don't predict.

[cptcatz]

10 hours ago, Ed, snow and hurricane fan said:

The op Euro is well supported by its ensembles (and has less smoothing than a mean at 10 days).  If there is something there, there will be a US landfall threat.  There are some storms on the GFS and Euro ensembles, but not enough to convince me there is more than a low chance of a TC occurring with no operational support when the pattern favors US landfall.

Maybe OT, looking at ensemble chi forecasts, and the Canadian, GFS and Euro forecasts are rather divergent.  Canadian has pretty decent upward forcing around this time the other models don't predict.

Nice post as right after that the 12z EPS blew up. We'll see if it sticks

https://twitter.com/HurricaneManWx/status/1687931125040070656

[Ed, snow and hurricane fan]

Bed time, GFS is out 8 days, and the only thing that stops a tropical depression from forming in the Caribbean (in an El Nino year, at that) is the Nicaraguan coast.  Not shear, not dry air.  See post on steering from 12 hours ago, this wave probably got there too soon, but personally, my low chance (say 20%) is now 30%, and maybe after tomorrow's 12Z run, I'll go full 40% orange.

[ldub23]

13 hours ago, Ed, snow and hurricane fan said:

Bed time, GFS is out 8 days, and the only thing that stops a tropical depression from forming in the Caribbean (in an El Nino year, at that) is the Nicaraguan coast.  Not shear, not dry air.  See post on steering from 12 hours ago, this wave probably got there too soon, but personally, my low chance (say 20%) is now 30%, and maybe after tomorrow's 12Z run, I'll go full 40% orange.

GFS has a TS and cane after that, maybe it  will get  more active

 

 

Less active. Looking at another  0/0 aug. In close  development  not  possible with a  mega  trof.

 

[Ed, snow and hurricane fan]

11 hours ago, ldub23 said:

GFS has a TS and cane after that, maybe it  will get  more active

 

 

Less active. Looking at another  0/0 aug. In close  development  not  possible with a  mega  trof.

 

Variations between the different models, but a general trend of the W ridge, EC trough and Atlantic ridge all backing to the W.  OTOH, my unofficial 30% chance of a TC close enough to the US to be interesting hasn't increased (may decrease back to 20% based on 12Z Euro and ensembles), 6Z and available 12 ensembles have backed off a bit from yesterday's 12Z and 18Z runs, but a pattern that could result in a Florida or SE USA hit does seem likely in the medium (week to ten day) range.  Edit- all the 12Z guidance has backed off somewhat.

[GaWx]

 Should the CFS due to its inferiority be ignored? For at least two runs, it has shown a TS moving into the NE Caribbean late week while no other operational shows any TC.

[Bhs1975]

 Should the CFS due to its inferiority be ignored? For at least two runs, it has shown a TS moving into the NE Caribbean late week while no other operational shows any TC.

Yes

[WxWatcher007]

4 hours ago, GaWx said:

 Should the CFS due to its inferiority be ignored? For at least two runs, it has shown a TS moving into the NE Caribbean late week while no other operational shows any TC.

I wouldn’t ignore the fact that it’s not a more “trusted” tropical model. I do think it’s useful to see a modest signal for TC genesis on the ensembles, but it doesn’t look like a strong signal for a development window, which is obviously the first step. 

[Ed, snow and hurricane fan]

I am curious what data made the models yesterday and lasr night that had them (and especially the ensembles) bullish for development a week to two weeks out, when they had not been seeing much TC activity before, and again today.  It wasn't just one model suite.  Maybe the lesson is I need two full days of multiple model enthusiasm.  Maybe three, before I buy in.

[ldub23]

17 minutes ago, Ed, snow and hurricane fan said:

I am curious what data made the models yesterday and lasr night that had them (and especially the ensembles) bullish for development a week to two weeks out, when they had not been seeing much TC activity before, and again today.  It wasn't just one model suite.  Maybe the lesson is I need two full days of multiple model enthusiasm.  Maybe three, before I buy in.

If  we  could  ever  have a reasonably  favorable MDR the  lower right  would  be  very interesting

 

[GaWx]

5 minutes ago, ldub23 said:

If  we  could  ever  have a reasonably  favorable MDR the  lower right  would  be  very interesting

 

 The lower right is what the CFS is developing into a TS that hits the NE Caribbean late this week. Bears watching.

[Windspeed]

I don't see any window of above normal activity now. We're getting into the midrange and I just don't see it. Looks like +ENSO is going to beat down +AMO to me. Any hyperactive stretch is going to be a surprise for me. Perhaps there is a pocket of favoribility in late August before El Niño takes over.

[GaWx]

26 minutes ago, Windspeed said:

I don't see any window of above normal activity now. We're getting into the midrange and I just don't see it. Looks like +ENSO is going to beat down +AMO to me. Any hyperactive stretch is going to be a surprise for me. Perhaps there is a pocket of favoribility in late August before El Niño takes over.
 

1. But the typical El Niño induced above normal Caribbean sheer is still nowhere to be found on the model consensus, including fwiw the CFS into early September. It actually is the opposite!

2. The 12Z EPS looks rather active to me after August 15th fwiw.

3. I'm not entirely dismissing the chance that the AEW now in the mid-MDR that ldub mentioned in reference to the satellite pic becomes a TC within a few days.

[bigtenfan]

7 hours ago, GaWx said:

1. But the typical El Niño induced above normal Caribbean sheer is still nowhere to be found on the model consensus, including fwiw the CFS into early September. It actually is the opposite!

2. The 12Z EPS looks rather active to me after August 15th fwiw.

3. I'm not entirely dismissing the chance that the AEW now in the mid-MDR that ldub mentioned in reference to the satellite pic becomes a TC within a few days.

If the wave is already out there and if it was considered even a lower level threat to the islands/FL/SEUS I would think that the NHC would have at least a 20% Lemon for development over the next 7 days. If the sheer isn't there Is  it the dry air that is preventing serious development?

[Ed, snow and hurricane fan]

The wave (LDub's lower right) still looks impressive, but I suspect it will do as all the waves have done (see 45W), weaken (dry air, and maybe warm mid-levels (abnormally high 500 mb heights in the tropics seem to get everyone) and weaken.  Euro ensembles are looking pretty inactive into mid August

 

 

[Windspeed]

1. But the typical El Niño induced above normal Caribbean sheer is still nowhere to be found on the model consensus, including fwiw the CFS into early September. It actually is the opposite!
2. The 12Z EPS looks rather active to me after August 15th fwiw.
3. I'm not entirely dismissing the chance that the AEW now in the mid-MDR that ldub mentioned in reference to the satellite pic becomes a TC within a few days.

Look at the setup for mid-month/Aug. 15th-16th on both recent runs of the ECMWF and the GFS. That look is not a favorable one for anything approaching the Caribbean. There are poorly positioned TUTTs and strong upper-level westerlies across Caribbean. It looks to me that something would need to get lucky positioning-wise north of the Greater Antilles. But any disturbance is going to have to overcome shear and subsidence in the MDR first. Generally, upper levels are calming down in around this time regardless of lingering subsidence in the central basin. You'll see signs in modeling from 500 to 200 hpa. I don't see those signs yet.

[GaWx]

3 hours ago, bigtenfan said:

If the wave is already out there and if it was considered even a lower level threat to the islands/FL/SEUS I would think that the NHC would have at least a 20% Lemon for development over the next 7 days. If the sheer isn't there Is  it the dry air that is preventing serious development?

Sometimes the NHC is too conservative. Example: Don. It had no chance for development going out 7 days until it was within 5 days of being named.

[GaWx]

2 hours ago, Windspeed said:

Look at the setup for mid-month/Aug. 15th-16th on both recent runs of the ECMWF and the GFS. That look is not a favorable one for anything approaching the Caribbean. There are poorly positioned TUTTs and strong upper-level westerlies across Caribbean. It looks to me that something would need to get lucky positioning-wise north of the Greater Antilles. But any disturbance is going to have to overcome shear and subsidence in the MDR first. Generally, upper levels are calming down in around this time regardless of lingering subsidence in the central basin. You'll see signs in modeling from 500 to 200 hpa. I don't see those signs yet.

 I stand corrected. I didn't realize that that much shear was being modeled on the recent GFS/Euro runs 8/15-16. Yes, I see the strong westerly shear in the Caribbean that you posted. I need to reassess the model consensus for Caribbean shear from midmonth on.

[GaWx]

3 hours ago, GaWx said:

 I stand corrected. I didn't realize that that much shear was being modeled on the recent GFS/Euro runs 8/15-16. Yes, I see the strong westerly shear in the Caribbean that you posted. I need to reassess the model consensus for Caribbean shear from midmonth on.

Followup:

 12Z GFS: Caribbean shear picks up Aug 12 and is strong the rest of the run. The 12Z GEFS also increases shear there Aug 12 and it is strong through at least Aug 17th (that's as far as run is out so far). 

Edit: 12Z GEFS strong Caribbean shear
continues for about a week but then decreases to near normal Aug 20-23 while the strong shear zone shifts just to the north of the Greater Antilles.

 Meanwhile, E US 500 mb ridging takes over on this GEFS run 8/19-8/23, which if it were to verify would potentially open the door to the E US for anything that might be in the W Atlantic then. I hope that would be shortlived if it happens. The run has 4 hurricanes out of 31 members off the SE coast late fwiw.

[ldub23]

At least  the euro is showing  some signs  of  life

 

[tiger_deF]

18z GFS has more tropical activity over Sub-Saharan Africa than it has in the entire basin by August 21st  

[Ed, snow and hurricane fan]

2 hours ago, tiger_deF said:

18z GFS has more tropical activity over Sub-Saharan Africa than it has in the entire basin by August 21st  

Euro weeklies do show chances of a TS, but less than 5%, call it nil, chance of a hurricane in the next four weeks.  I don't think @ldub23's 0/0/0 August works out, and I still think there is probably a hurricane, but the odds of 0/0 H/MH are growing.

[jconsor]

7 hours ago, Ed, snow and hurricane fan said:

Euro weeklies do show chances of a TS, but less than 5%, call it nil, chance of a hurricane in the next four weeks.  I don't think @ldub23's 0/0/0 August works out, and I still think there is probably a hurricane, but the odds of 0/0 H/MH are growing.

The Euro weeklies almost never show any chance  for hurricanes (>5% on those maps) in my experience.  More relevant to look at tropical depression *anomaly* probability and TS probability.

[jconsor]

Some important context re: the ECMWF seasonal outlook.  Firstly, as others have pointed out, the Aug outlook is for Sep onward.  So if we were to have an active Aug, that would be not be reflected in the ECMWF outlook.  I go through some other important points to keep in mind in this thread:
 

 

[ldub23]

Related to my deleted  post the euro shows some signs  of  life. The gfs at the end  of  its run shows a large high building  in the  Northeast that will change the  pattern and allow the season to start IF the  change actually  happens and IF anything  is around to develop.

 

[Ed, snow and hurricane fan]

44 minutes ago, ldub23 said:

Related to my deleted  post the euro shows some signs  of  life. The gfs at the end  of  its run shows a large high building  in the  Northeast that will change the  pattern and allow the season to start IF the  change actually  happens and IF anything  is around to develop.

 

Verbatim, those 2 lows will be struggling bigly with dry ait.  August 21 to Sept 4, the Euro weeklies like along and off ECUSA, maybe something changes.  I watched a Twitter video, a Savannah, GA TV met.  He thinks the season will pick up in 2 weeks, but he based that mostly on climatology.  The season 'should' pick up because most seasons do.  I'm not sure what is supposed to change.  Dry air doesn't seem like it is going anywhere soon.