Jump to content
  • Member Statistics

    17,608
    Total Members
    7,904
    Most Online
    Vesuvius
    Newest Member
    Vesuvius
    Joined

2023 Tropical Tracking Thread


SnowenOutThere
 Share

Recommended Posts

We have Emily in the eastern MDR

Tropical Storm Emily Discussion Number   1
NWS National Hurricane Center Miami FL       AL072023
1100 AM AST Sun Aug 20 2023

The large area of low pressure we have been monitoring 
over the last several days to the west of the Cabo Verde Islands 
has finally developed a well-defined circulation per recently 
received satellite wind data. In addition, the scatterometer wind 
data also suggest the system has developed a robust wind field on 
its northern semicircle, with ASCAT-B/C both showing believable 
wind retrievals in the 40-45 kt range. Therefore, advisories are 
being initiated on Tropical Storm Emily this morning with maximum 
sustained winds of 45 kt, which is in good agreement with the latest 
1200 UTC TAFB Dvorak fix. 

The estimated motion of the tropical storm is slowly off to the 
west-northwest, at 300/9 kt. Over the next several days, Emily 
should maintain a general west-northwestward motion as it remains 
steered by a low-level ridge centered to its north. A gradual turn 
to the north is anticipated after Emily becomes a remnant low, 
rounding the southern periphery of this subtropical ridge. The track 
guidance is in fairly good agreement on this scenario, and the 
initial track forecast lies in between the simple and corrected 
consensus aids.

Emily might already be near its peak intensity, as vertical wind 
shear is expected to substantially increase over the cyclone in the 
next 24-36 hours as it remains embedded in a fairly dry mid-level 
environment. While it is possible a bit more intensification occurs 
today, it seems more likely the system will soon succumb to the 
increasingly hostile environment over the next several days. Both 
the GFS and ECMWF suggest Emily will cease to produce organized 
convection in about 48 hours, and the official intensity forecast 
shows it becoming a post-tropical remnant low at that time. There is 
some chance the environment becomes more favorable again in 4-5 
days, but a regeneration scenario will not be shown in the official 
forecast for now. 



FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 19.5N  38.8W   45 KT  50 MPH
 12H  21/0000Z 20.3N  39.9W   45 KT  50 MPH
 24H  21/1200Z 20.9N  41.6W   40 KT  45 MPH
 36H  22/0000Z 21.5N  43.6W   35 KT  40 MPH
 48H  22/1200Z 22.5N  45.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  23/0000Z 23.6N  47.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  23/1200Z 25.1N  49.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  24/1200Z 29.8N  50.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  25/1200Z 36.0N  51.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin

 

dtrs1jt.png

  • Like 2
Link to comment
Share on other sites

Let's do a quick deep dive on two of the five areas I highlighted yesterday--the disturbance in the Gulf of Mexico and Invest 90L. 

Gulf Disturbance
I tagged yesterday's disturbance with 60% odds of eventual development when it was moving through the Bahamas and Florida, and now that it has reached the eastern Gulf I am even more bullish given today's satellite appearance. 

giphy.gif

giphy.gif

To be clear: this one needs some work and there's not a lot of time to do it. That said, the quick convective burst and indications that it's trying to form into a low makes it worth an invest tag to me. 

The environment overall looks favorable. There is very little shear present and that should remain the case as this moves west. 

wg8shr.GIF

 

Once again, we obviously know that the SSTs are not an issue, with literally some of the warmest water on Earth in the Gulf and a deep reservoir of OHC. 

i46D6tB.png

UB3eBVD.gif

Moisture looks solid not great, but given where the vorticity is trying to tighten and the convective bursts we're seeing, I don't think drier continental air is a limiting factor yet. We'll see. 

giphy.gif

uToPhlD.gif


I think time is the greatest limiting factor here, but kind of like Hanna a few years ago, if this can get a good organizational burst today/tonight that could bode well for another named storm to develop as this enters the western Gulf and the TX/Mexico border early Tuesday. Again, not a lot of time, and nothing can happen until there's a legitimate low, which we do not have yet. 

Invest 90L
This one is worth watching IMO. I think it is a contender to be the strongest system of the season thus far in the long range. Recon is expected to sample this later today and I believe they will find a tropical storm. 

giphy.gif

In the visible you can clearly see a low level circulation, but there are some significant issues keeping this from taking off. There is very evident northerly shear that is pushing the convective burst that should be over the center further south. That's how we can see that there is a clear LLC :lol: 

giphy.gif

In addition to the shear, there is dry air to the north that is causing issues as well. I don't expect dry air to be as big an issue long term, but for now the shear/dry air combo is keeping this one in check. This would be taking off IMO without the combination, because the convective bursts that we have seen have been persistent and intense--really allowing this to be as organized (and it's not terribly organized) as it is now. 

I'm intrigued by the long range because it looks like the environment after a potential landfall near DR/Haiti will be conducive for additional development. In fact, both the GFS and Euro operational guidance has this becoming a strong system in the open Atlantic. 

I still think we need to wait for this to cross the Antilles back into the Atlantic before fully understanding the long term future of 90L, but overall, troughing is going to lift this north into the Atlantic.

How far west this gets before that turn seems important, and certainly what other impulses in the Atlantic exist ahead of 90L, because both the Euro and GFS have a ridge over the CONUS and have trended toward a subtropical ridge building in to drive what is likely a named storm by then northward. Throw in any kind of trough in there to either cause a weakness between the ridges to go OTS, or in the case of a cutoff in the east change steering toward land, and we have a very complex forecast.  

Eb9KopA.png

Sj66PNr.png

Given the complexity of the forecast long range, and the shift west we've seen in ensemble guidance as 90L continues to develop, this one is certainly worth a close eye in Bermuda, Atlantic Canada, and to a lesser extent the US east coast. 

A lot of tracking to do this week. 

  • Like 7
  • Thanks 2
Link to comment
Share on other sites

2 hours ago, WxWatcher007 said:

Should have Franklin at 5pm with Invest 90L. Recon finding TS winds and I think enough of a closed circulation. 

Yeap.

 

000
WTNT33 KNHC 202053
TCPAT3

BULLETIN
Tropical Storm Franklin Advisory Number   1
NWS National Hurricane Center Miami FL       AL082023
500 PM AST Sun Aug 20 2023

...TROPICAL STORM FRANKLIN FORMS IN THE CARIBBEAN SEA..
...TROPICAL STORM WATCHES ISSUED FOR THE SOUTH COAST OF HAITI AND
THE DOMINICAN REPUBLIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...14.6N 67.1W
ABOUT 270 MI...435 KM SSE OF ISLA SAONA DOMINICAN REPUBLIC
ABOUT 270 MI...435 KM SSW OF SAN JUAN PUERTO RICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

.....

  • Like 1
Link to comment
Share on other sites

WxWatcher007 2023 Atlantic Peak Season Forecast

Finally, I have the time to share my annual thoughts on the peak of the Atlantic hurricane season. This is my fifth annual forecast and the lead up to today has seen very significant uncertainty on the tenor of the season. The season so far has actually been normal in number of storms and ACE to date, which means active for a Nino. As I write, we suddenly have a TC outbreak in the Atlantic. 

W1UAt2E.png

The switch is definitely flipping in the basin. 

NxfmOSE.png

Each year on August 20, the late Dr. William Gray and his team would ring a bell, symbolizing the start of peak season. This year, we have a historically warm basin battling a Nino that is gradually increasing in influence.

What does the August 20 - October 20 period hold? Here's my forecast. 

Peak Season Forecast (Aug 20-Oct 20)
Named Storms: 13 
Hurricanes: 6
Major Hurricanes: 3

Emily, Franklin, and Gert became named storms yesterday. Had I posted on the 20th, I would have forecast Emily and Franklin to develop, but not Gert. As a result, my verification will include that. The forecast also predicts PTC 9 and Invest 92L to become NS. That's already pretty active. 

With the current outbreak, I think the risk of a below normal season has diminished. I expect this active window to be confined to the next 4 weeks, with a sharp drop off in activity by September 20. That doesn't mean we can't/won't have NS/H/MH during the late period, but I think at that point, the evolving MJO and Nino will start closing things down. 

Over the past four seasons, I've done well with my forecasts. I view being within +/- 1 as a success, with points off the greater the error. I earned a B+ in 2019, A- in 2020, a disappointing C in 2021, and a rebounding B- in 2022. 

As a reminder, the historical average is 14/7/3. With this peak season forecast I am now forecasting an overall 18/7/3 with more NS than normal, a normal hurricane number, and normal MH number due to decreasing shear during the peak and the exceptionally warm basin even in the central Atlantic. I see ACE around normal. 

1. ENSO
After a three year Nina, we're solidly in an El Nino regime. Of course, every ENSO event is different, and intensity/location matters a lot. Given what I project (and I will admit I am not as good with the intensity/location stuff) and what I've seen so far, the fundamental atmospheric response in the Atlantic that allows for anomalously high shear through the basin has not yet occurred, despite the shear in the basin currently. During the peak guidance actually shows a decrease in shear, but the influence of the Nino should eventually increase, bringing a wind down of activity around the basin (particularly the Caribbean) approximately four weeks from now.   

DURUoxv.png

mocPJg8.png

2. West African Monsoon
The WAM has shown mixed signals so far this season, but now that we're entering the peak it is ramping up. We've seen numerous strong African Easterly Waves (AEWs) that have rolled off Africa, and if the GFS Ensembles are to be believed, it should continue through at least early September. With CV season coming, this is essential to the forecast, even if the MDR remains somewhat hostile with subsidence because it provides a launching point for strong waves to survive the trek into the western Atlantic where there may be more favorable conditions depending on shear.

giphy.gif 

3. Wind Shear
For the most part, shear has been the opposite of what you'd expect for a Nino. Recently it has gotten much worse, but that hasn't stopped development across the basin. It has, however, limited intensity potential, which is part of the reason why I am not interested in going above normal on H or MH numbers.

L67kdaN.gif

 

I do think we're going to continue having issues with TUTTs, but I don't anticipate the incredibly consistent wave breaking we saw last year that really capped potential in the basin. There is fairly high confidence in this, given the agreement by the ensembles and the seasonal trend thus far. 

 

giphy.gif

giphy.gif


gRpiQ6i.gif

BL81uth.gif

0V2CNib.gif


Eventually I think the Nino will take over, but not until the damage has been done.  


CV2122n.png


 

4. SST Anomalies/OHC
If we didn't have the extraordinary SST anomalies and OHC dominating the basin, this would undoubtably be a BN season. This has really allowed for the early MDR NS, marginal activity in the basin in the face of shear/dry air, and for Don to become our first hurricane in July. It is historic warmth, and while SSTs are not the piece that drives a season, they are an essential piece. 

 qjhbmZK.png

ysbYBmN.png

cAUsz1I.gif
 

5. SAL & Stability
The check on the season so far hasn't been shear, it has been SAL and stability. After being historically low earlier in the season, SAL came back with a vengeance in July and August, stabilizing much of the basin and completely closing down even cloud development in the MDR. In fact, vertical instability has been well below climo all year in the tropical Atlantic. 

su7qsUT.gif

sApgqAO.gif

fXZ9n90.gif

Times are changing though. SAL is on the decline as we reach the peak of the season, as is usually the case. The sacrificial waves, which all became named storms along the monsoon trough, has dramatically decreased SAL and moistened the environment around the basin, further increasing confidence in an active month ahead. I can't embed the gif, but the link is below. 

Jof5zq2.jpg

https://tropic.ssec.wisc.edu/real-time/sal/g16split/movies/goes16split.html

5. CCKW/MJO
Finally, although we can't see very far, we do also have another factor making an active month more likely. It looks like we are getting favorable passage of a CCKW and the MJO looks to be on the side of Atlantic activity for the next few weeks. This should continue to promote vigorous waves. Not all will develop, but it should keep moistening the MDR and allow for waves to get further west.

gDwwjwO.gif

Ova7LPW.png


Overall
I didn't want to go big, because we still don't know how much shear and stability will truly subside in the coming weeks. Honestly, before this week I was leaning BN overall. With the current state of the Atlantic however and a more favorable period coming aside from the annual start of the climatological peak, I do believe we see an active period that gets us to near normal before a decline after September 20 and an abrupt end by October 20. 

I do think that we see a lot of named storms, but because I am hedging a little more conservative I think we have fewer hurricane chances of those NS. That said, the ones that do become hurricanes will have a chance to become majors, leaving me to predict that 3 of the 6 hurricanes I project developing become majors. 

Final Note--Landfall Odds
The past three years have seen high end storms landfall in the US, and I don't think that changes this year. With higher activity comes a greater statistical chance of a US landfall, and I do believe we have a fourth consecutive year with a major hurricane landfall in the continental United States. 

We'll see what happens. Happy tracking. 

  • Like 7
  • Thanks 3
Link to comment
Share on other sites

22 hours ago, Its a Breeze said:

Looks like Gert is one of those 'screw it, just name it' storms :). Don't think it actually reached TS strength but *shugs*

Should disappear in an advisory or two.

Yeah, seems like they name everything in recent years. I wonder why............

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...