2023 Atlantic Hurricane season

[GaWx]

Though the 0Z UKMET still has no GOM TC, it for the third time in a row has a TD form in the far E MDR at the end of its run:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 168 HOURS
FORECAST POSITION AT T+168 : 14.2N 17.6W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 24.08.2023 168 14.2N 17.6W 1004 34

[GaWx]

The 0Z EPS just through day 10 is very busy with many active members for 98L, 99L, the Gulf low, and two followup MDR AEWs. Also, late in the run there are ~half the members moving up from the Bay of Campeche with some members crossing over from the Pacific late in the run. So, that's a total of six different features of interest just through day 10. Thus if only half of these end up as a TC, that would be enough to yield three new TCs by 0Z on 8/27 (very busy vs climo averages for just a ten day period). That's like night and day vs what the models showed for the same part of August last year. Two of these six (the two in the Gulf) would be direct threats to the CONUS.

 I originally predicted 3 NS for August. I feel pretty good about that prediction.

[Ed, snow and hurricane fan]

98L looks good on CIMSS MIMIC TPW.   GFS suggests it doesn;t live long, but a name is possible.  Shear and dry air as it heads NW.   I'm interested in seeing if 99L can avoid development and get closer to the Caribbean.

 

I want the Gulf lemon to develop, but models besides Euro, and even op Euro is meh, don't close a depression.  GFS rainfall amounts from the wave are not impressive at all.  Under half an inch.  Euro's wave is generally an inch.  Only a couple of GFS ensembles close  a low.  20% probs are too high, for what will be an underwhelming wave with not that much rainfall.

 

El Nino shear is coming, only a small window for anything before everything becomes unfavorable.  LC's 11/4/1 seems like a good call.

 

 

[NorthHillsWx]

Looks like a bunch of short lived sheared systems but an active stretch nonetheless 

[jconsor]

Beware of recency bias! The downcasting of the tropical Atlantic happens nearly every year when there is a Jul/early Aug lull in activity.

 

I wouldn't be so sure *all* of the systems next two weeks will be weak and short-lived.  I see potential for one or two stronger ones, mainly in the subtropical central Atlantic and GOM/Bahamas area.

 

 

 

 

 

 

 

[NorthHillsWx]

41 minutes ago, jconsor said:

Beware of recency bias! The downcasting of the tropical Atlantic happens nearly every year when there is a Jul/early Aug lull in activity.

 

I wouldn't be so sure *all* of the systems next two weeks will be weak and short-lived.  I see potential for one or two stronger ones, mainly in the subtropical central Atlantic and GOM/Bahamas area.

 

 

 

 

 

 

 

While I agree with your comments about the SAL dissipating somewhat allowing for the increased chances of activity, it comes with a period of significant wind shear in pockets across the basin. I do not see a path for a strong storm over the next 2 weeks unless something develops rapidly in a window but with multiple TUTTs and SAL sticking around even if diminished it does not look like an environment that would support a long track system especially one of a stronger intensity 

[GaWx]

12Z UKMET...This appears to be from 99L. It forms and dissipates within the Caribbean:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 126 HOURS
              FORECAST POSITION AT T+126 : 15.3N  72.4W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    0000UTC 23.08.2023  132  15.7N  73.1W     1003            32
    1200UTC 23.08.2023  144  16.6N  73.6W     1005            33
    0000UTC 24.08.2023  156  17.1N  74.3W     1006            28
    1200UTC 24.08.2023  168              CEASED TRACKING

 

Edit: Upon further review, this may be from a feature west of 99L.

[GaWx]

Once again, the UKMET has no GOM TC. But for the 4th run in a row, it has TCG late in the run in the far E MDR:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 150 HOURS
FORECAST POSITION AT T+150 : 12.7N 17.2W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 24.08.2023 156 13.7N 18.3W 1004 32
1200UTC 24.08.2023 168 15.0N 21.3W 1005 30

[WxWatcher007]

https://twitter.com/philklotzbach/status/1692220172457971992?s=46&t=Nn9Cx92_8118fPdhHPdJHw

[WxWatcher007]

12z runs again show a complicated setup in the Atlantic, with a potentially weak system in the Gulf, high uncertainty (but low ceiling) for the areas along the disintegrating monsoon trough, and a long range potential for a CAG to develop. 

The Euro continues to actually focus MDR development further west, with a brief TC in the Caribbean before running into a buzzsaw of shear. Verbatim, it'd be a risk for PR and the USVI early next week. The Gulf thing becomes a weak system, but doesn't have time to consolidate enough to organize into something stronger.

[WxWatcher007]

Interesting end to the Euro as that western area I just mentioned maybe gets left behind by a trough and the EPAC ejects vorticity into the BOC leading to a TC in the Gulf. Not really worth much headspace, just a reminder of how complex this overall evolution is--there will be opportunities for TC genesis though, IMO. 

[cptcatz]

12z GFS, CMC, and Euro are basically telling us we have no idea what's gonna happen. Jeez can we get some model consistency here please?

[Ed, snow and hurricane fan]

The model most enthusiastic about a needed TD/TS for Houston, where it hasn't rained since July 4th weekend and every day since July 30 has been >100F, the Euro, has backed down.  Still decent Euro ensemble support, but nothing from the GFS ensembles.  The trend is a weaker and weaker wave.  Euro is starting to trend towards GFS rainfall.

 

Interesting speculation on which part of the MT develops, 99L can affect the islands, but everything else is just guessing where, when and if the next fish storm forms.  But a door closes and a window opens, I know Hilary will be passing cold water once past the central Baja, but I think it might still be a named and not yet post-tropical storm when it reaches SoCal.

[Ed, snow and hurricane fan]

OT 3rd time in a day I get a notification @ldub23 has quoted me in this thread, and when I look, there is no quote.  I wonder if he is replying, and them immediately deleting just to make me look.

[Scott747]

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

OT 3rd time in a day I get a notification @ldub23 has quoted me in this thread, and when I look, there is no quote.  I wonder if he is replying, and them immediately deleting just to make me look.

Those posts have gone away because it's the same schtick as it always is.

In a nutshell that poster has cancelled the rest of August and September. Also October will be cancelled along with 2024, 2025 and beyond.

[WxWatcher007]

98L, although convectively disorganized, looks to be leading the pack as it has a more robust low level spin and maybe some convection trying to organize. It’s the front runner tonight to be the first NS since Don, though a combination of dry air and shear will likely kill it next week. 

98L is more convectively active but it still looks to be tied up in the monsoon trough with elongated vorticity and is still connected by my eye to the new lemon just to the west. That lemon, which the Euro continues to like, could become a player for the Antilles of it can separate. It should be noted that this region has been most convectively active, so it stands to reason if it can acquire spin and avoid SAL to the north given its location it has a legitimate chance. 

Meanwhile, nothing new for the Gulf lemon. Still worth watching but I don’t think we get a better sense of things until the disturbance reaches the Gulf. 

[GaWx]

8/18/23 like night and day vs 8/18/22 in MDR:

8/18/22 2AM EDT TWO:

8/18/23 2AM EDT TWO: SEVEN features have significant activity on the 0Z EPS just through day 10! That almost has to be near a record:

[WxWatcher007]

Both 98L and 99L look like they have a low level circulation going, but are struggling with dry air nearby. 

It looks like the lead MDR area (lemon) is also trying to spin independently but has a lot of work to do. I’m intrigued by this one because it’s south of shear and dry air and remains convectively active, though very disorganized. 

As we’ve seen with successive diurnal cycles, convection is picking up again with the disturbance that’s now entering the Bahamas. Nothing much there yet though. It is entering a low shear environment, so we’ll see what if any organization can occur before the Gulf, not because I anticipate anything other than rain for Florida, but because even modest sharpening of the wave can open the door for slightly faster development in the Gulf.

[Ed, snow and hurricane fan]

24 minutes ago, WxWatcher007 said:

Both 98L and 99L look like they have a low level circulation going, but are struggling with dry air nearby. 

It looks like the lead MDR area (lemon) is also trying to spin independently but has a lot of work to do. I’m intrigued by this one because it’s south of shear and dry air and remains convectively active, though very disorganized. 

As we’ve seen with successive diurnal cycles, convection is picking up again with the disturbance that’s now entering the Bahamas. Nothing much there yet though. It is entering a low shear environment, so we’ll see what if any organization can occur before the Gulf, not because I anticipate anything other than rain for Florida, but because even modest sharpening of the wave can open the door for slightly faster development in the Gulf.

Looking at the CIMSS product, the best low-mid level vorticity is a bit S of the convection, with the max vort over E Cuba.  I hope convection can pull vorticity N, I want a NW Gulf system that breaks all month no rain/100F here in SETX.  Modelling is shifting S towards the Texas Coastal Bend, which doesn't help me.    I can now see it on MIMIC-TPW product, it wasn't so obvious before.

 

In the MDR, 99L looks better to me on satellite, but 98L looks better on the TPW loop.  https://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&prod=natl&timespan=24hrs&anim=html5

[tiger_deF]

Worth looking at the vorticity as well. 99L is well on its way.

[WxWatcher007]

Interesting that the GFS now follows the euro and tries merging the lemon and 99L. Really complicated forecast for the Antilles.

Meanwhile, models continue the signal for the eventual Gulf lemon. It’s been thrown around, but I kind of like the weaker Hanna analog.

[GaWx]

Though it still has no GOM TC, the 12Z UKMET continues to have E MDR TCG from a non-tagged AEW next week:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 126 HOURS
FORECAST POSITION AT T+126 : 14.5N 18.4W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 24.08.2023 132 14.7N 19.2W 1004 30
1200UTC 24.08.2023 144 15.8N 22.1W 1003 35
0000UTC 25.08.2023 156 17.0N 25.5W 1005 37
1200UTC 25.08.2023 168 17.6N 28.4W 1005 35

[WxWatcher007]

40% D7 odds now for the Gulf 

[GaWx]

1 hour ago, TheGhostOfJohnBolaris said:

Fort Myers has to be a little nervous looking at the 12z GFS..

 Although I'm not saying they can't end up with a dangerous situation then, I'd say that the worry regarding the 12Z GFS would be the case for folks not realizing that the exact 10 day position on the GFS or really on any operational for that matter is of very limited forecasting value since they jump around a lot that far out from run to run. Regarding GFS runs over the last 5 days, only the 0Z 8/16 run has anything similar. 

[Kevin Reilly]

2 hours ago, TheGhostOfJohnBolaris said:

Fort Myers has to be a little nervous looking at the 12z GFS..

They are aware as they should every year.  My friend lives in Cape Coral and Sanibel ground zero from Ian last year.  Thank goodness it is only one run but definitely need to keep tabs with 92-97 water temps it is a powder keg. The only thing the models do for me right now is tell me that the conditions for tropical cyclone development is improving, Saharan Dust is currently diminishing, water temps are hot, but all of the models are showing different solutions which will be evident run to run especially 200+ hours out. 

[WxWatcher007]

Euro, GFS, and CMC all have something trying to come out of Central America/EPAC into the basin late next week. It’s entirely irrelevant how strong those op runs strengthen something in the long range, the signal is what matters. There are a lot of moving pieces here.

[shaggy]

1 hour ago, GaWx said:

 Although I'm not saying they can't end up with a dangerous situation then, I'd say that the worry regarding the 12Z GFS would be the case for folks not realizing that the exact 10 day position on the GFS or really on any operational for that matter is of very limited forecasting value since they jump around a lot that far out from run to run. Regarding GFS runs over the last 5 days, only the 0Z 8/16 run has anything similar. 

Especially since there was little support from the gefs

[Ed, snow and hurricane fan]

1 hour ago, WxWatcher007 said:

Euro, GFS, and CMC all have something trying to come out of Central America/EPAC into the basin late next week. It’s entirely irrelevant how strong those op runs strengthen something in the long range, the signal is what matters. There are a lot of moving pieces here.

Some Pacific basin lows cross into the BoC.  I think the Euro ensembles are too juiced this year, but getting a named storm from the Pacific to cross basins would be different.

[WxWatcher007]

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

Some Pacific basin lows cross into the BoC.  I think the Euro ensembles are too juiced this year, but getting a named storm from the Pacific to cross basins would be different.

It has absolutely been too amped IMO this season, but it has accurately predicted the breakdown of the monsoon trough, and I think it’ll be right with TC genesis in the Gulf next week. 

I think it’s going to be really complex, but I do think something tries to come out of the western Caribbean or Gulf late next week with some kind of land threat the last week of August as a result. 

[cptcatz]

3 hours ago, GaWx said:

 Although I'm not saying they can't end up with a dangerous situation then, I'd say that the worry regarding the 12Z GFS would be the case for folks not realizing that the exact 10 day position on the GFS or really on any operational for that matter is of very limited forecasting value since they jump around a lot that far out from run to run. Regarding GFS runs over the last 5 days, only the 0Z 8/16 run has anything similar. 

Quite a few of the GFS runs have been showing a CAG like storm forming in the western Caribbean. CMC has been showing it a lot too and now EPS is hinting it at. Where it goes from there is a toss up but the fact that it forms on many models is what's important.