PTC 4

[GaWx]

 Invest 99L has just been declared for the surprise well organized disturbance over the Yucatan. What will it do once into the Bay of Campeche? Models to this point have done next to nothing with it. Now we'll see what the HWRF and HMON do or don't do.

 

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Aug 18 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Southwestern Gulf of Mexico:
Showers and thunderstorms associated with a tropical wave located 
over northern Guatemala and southeastern Mexico have become a little 
better organized since yesterday. This system is forecast to emerge 
into the Bay of Campeche tomorrow, where an area of low pressure 
could form. After that, additional slow development of this system 
is possible while it moves northwestward over the southwestern Gulf 
of Mexico.  By Saturday night, the system is expected to move 
inland over northeastern Mexico.  An Air Force Reserve Hurricane 
Hunter aircraft is scheduled to investigate the system on Friday, 
if necessary.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

Forecaster Beven

 

[WxWatcher007]

Setting aside the models for a minute, the environment looks decently favorable for a quick spin up by my eye. Emphasis on quick, as this will be inland by late Saturday night by current projections. 

First, the Bay of Campeche usually delivers in aiding the spin of a developing low due to its concave topography. While not a determining factor in tropical cyclone genesis, for something that's on the fence, sufficient time in the BOC can help focus spin. That's necessary here, as something too broad won't be able to organize sufficiently to become a TC.  

Sea surface temperatures and OHC are not a concern, as these are some of the warmest waters in the basin. 

 

Wind shear doesn't look like too much of a concern either, as an upper low seems to be pulling back as the invest moves into the BOC. If this is too slow to occur, that'd put a lid on significant development.  

Currently, despite the declining intensity of convective activity over Central America and Mexico, we see a disorganized but fairly impressive mid-level structure for 99L with clear mid level spin and hints of outflow.

The two biggest limiting factors are time and proximity to land. As I said at the start of the post, this is a quick one. We saw with 98L that the clock really does tick on development.

99L should be offshore tonight and crossing the NE Mexico border by late Saturday. 

While proximity to land may be an issue early on for development, this may be an instance where it helps right before "landfall", as a northwest (but ideally a NNW) heading toward the coast on final approach could help tighten a circulation. 

The models may not be fond of this one, but it has a legitimate chance of development. 

The key things to watch this evening IMO:

1) Does convective activity near the apparent mid-level center increase once it has crossed into the BOC? 

2) Does whatever convective activity allow for a center reformation further east, which would provide more time over water (increasing development odds) and allow for a further north track?

[GaWx]

 By comparing the track density over the Bay of Campeche (using Weathernerds) for the last 4 EPS runs, one can clearly see a trend for an increase in the # of members with 20-30 knot surface lows forming in the S Bay of Campeche by tomorrow before heading into NE MX on Saturday. Yesterday's 18Z only had 2 followed by ~10 on today's 0Z and 6Z. The 12Z just out has ~15.

[Ed, snow and hurricane fan]

I'm not feeling it except as 98L all over again, but from the tropics and thus coming from a different direction to move quickly inland.  SHIPs likes it a bit more than 98L, maybe it gets a number, maybe even makes sure Danielle returns in 2028.

 

No rain at all from my yard, but another August front forecast by GFS means drops 2 inches by Tuesday night.  Not a drought buster, the front.  It might be feeding moisture to the remnant front later in the week, but the direct rains looks like they stay South of the Border.

 

 

[WxWatcher007]

As expected, convection is waning this evening, but it reveals a robust (albeit elongated) mid-level center. This center is moving westward which isn't ideal for time over water, but it should be in the BOC in a matter of hours. From there, we'll see if there's a convective response.

[WxWatcher007]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Thu Aug 18 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Southwestern Gulf of Mexico:
Scattered showers and thunderstorms are associated with a tropical 
wave located over southeastern Mexico that is expected to emerge 
into the Bay of Campeche tomorrow morning. Environmental conditions 
appear favorable for additional development, and a tropical 
depression could form while the system moves northwestward over the 
southwestern Gulf of Mexico on Friday or Saturday. However, by 
Saturday night, the system is expected to move inland over 
northeastern Mexico, which will end its chances of development. An 
Air Force Reserve Hurricane Hunter aircraft is scheduled to 
investigate the system tomorrow, if necessary.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Flynn/Papin

[NorthHillsWx]

4 minutes ago, WxWatcher007 said:

As expected, convection is waning this evening, but it reveals a robust (albeit elongated) mid-level center. This center is moving westward which isn't ideal for time over water, but it should be in the BOC in a matter of hours. From there, we'll see if there's a convective response.

You can see the shear affecting the cloud tops west of it. Imo it would need to be further north to offset that pocket of shear, which may be retrograding SW, but it’ll be close

[WxWatcher007]

35 minutes ago, NorthHillsWx said:

You can see the shear affecting the cloud tops west of it. Imo it would need to be further north to offset that pocket of shear, which may be retrograding SW, but it’ll be close

Very close. I love this stuff.  

[Ed, snow and hurricane fan]

In the all important closer to MBY to kill the drought in two cold fronts and one TC, trends are favorable.  

 

In the modeled intensities, models are even less impressed than yesterday.

[NorthHillsWx]

Believe 99L has hit the shear factory. I thought it was further north than it was until the mid level center got exposed last night. Getting clobbered by shear this morning. Next. 

[WxWatcher007]

The shear is certainly nearby at first light, but I don’t think it’s having a significant impact yet looking at visible imagery. Not sure if recon still plans to fly this morning.

[GaWx]

 Based on the vis loop I just saw, I think the NHC chance for a TD forming will rise later today from the current 40%. With that, the chances of this becoming the first NS for this month are also rising imho. This may already be near TD status.

 Edit 10:45 AM EDT: With what appears to me to be a developing surface low with plentiful convection over the center, SSTs near the warmest in the Atlantic basin at 30 C/86 F, likely at least 18 hours left over open water/24+ hours before landfall, and this often being a favorable area to develop per history, I think this has a high chance to make it all of the way to TS status. Looking back, there have been a good number of examples of a TS forming within 24 hours of leaving the Yucatan as still a sub-TD near this location and with this trajectory.

[GaWx]

Special TWO issued at 10:50 AM!

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1050 AM EDT Fri Aug 19 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Special outlook issued to update discussion of the disturbance in 
the southwestern Gulf of Mexico.

1. Southwestern Gulf of Mexico:
Satellite imagery indicates that showers and thunderstorms 
associated with the broad low pressure area over the southwestern 
Gulf of Mexico and the Bay of Campeche are getting better organized.
Environmental conditions appear favorable for additional 
development, and a tropical depression could form later today or
on Saturday while the system moves northwestward across the 
southwestern and western Gulf of Mexico.  However, by Saturday 
night, the system is expected to move inland over northeastern 
Mexico, which will end its chances of development. An Air Force 
Reserve Hurricane Hunter aircraft is scheduled to investigate the 
system this afternoon.  Interests along the northeastern coast of 
Mexico and the lower Texas coast should monitor the progress of 
this system.  Regardless of development, this system could bring 
locally heavy rains to portions of northeastern Mexico and southern 
Texas over the weekend.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

Forecaster Beven

[Ed, snow and hurricane fan]

35 minutes ago, GaWx said:

 Based on the vis loop I just saw, I think the NHC chance for a TD forming will rise later today from the current 40%. With that, the chances of this becoming the first NS for this month are also rising imho. This may already be near TD status.

 Edit 10:45 AM EDT: With what appears to me to be a developing surface low with plentiful convection over the center, SSTs near the warmest in the Atlantic basin at 30 C/86 F, likely at least 18 hours left over open water/24+ hours before landfall, and this often being a favorable area to develop per history, I think this has a high chance to make it all of the way to TS status. Looking back, there have been a good number of examples of a TS forming within 24 hours of leaving the Yucatan as still a sub-TD near this location and with this trajectory.

It looks like the plane should fly in, I suspect they'll find either a TD or NHC will PTC it to issue watches for Mexico, but the hurricane models are not impressed.  If this goes Humberto before hitting Tampico (give or take), at this point, it would be a good demonstration of models needing improvement.  Looking at SHIPS and wondering why things are all zero or negative on intensity

[Ed, snow and hurricane fan]

1 minute ago, GaWx said:

Special TWO issued at 10:50 AM!

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1050 AM EDT Fri Aug 19 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Special outlook issued to update discussion of the disturbance in 
the southwestern Gulf of Mexico.

1. Southwestern Gulf of Mexico:
Satellite imagery indicates that showers and thunderstorms 
associated with the broad low pressure area over the southwestern 
Gulf of Mexico and the Bay of Campeche are getting better organized.
Environmental conditions appear favorable for additional 
development, and a tropical depression could form later today or
on Saturday while the system moves northwestward across the 
southwestern and western Gulf of Mexico.  However, by Saturday 
night, the system is expected to move inland over northeastern 
Mexico, which will end its chances of development. An Air Force 
Reserve Hurricane Hunter aircraft is scheduled to investigate the 
system this afternoon.  Interests along the northeastern coast of 
Mexico and the lower Texas coast should monitor the progress of 
this system.  Regardless of development, this system could bring 
locally heavy rains to portions of northeastern Mexico and southern 
Texas over the weekend.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

Forecaster Beven

The days I wish I could still upload meme gifs....

[WxWatcher007]

Still need to see what recon finds, but I said it yesterday—the convective cycles were really nice with this one over a few days and this morning would be important for TC chances. It checked the box. 

Now, it’ll need to tighten up and continue its convection through the downward convective diurnal phase. 

Still a little early but it looks like the shear has relaxed a little on visible. It wasn’t really impacting the apparent MLC though. 

[SnoSki14]

Lid normally comes off after tomorrow but this year looks slower than recent years so could be a 7-10 day delay before things pop off. 

I suspect September/October will be quite active as dry air continues to slowly subside. Shear is actually normal to below normal in MDR

[GaWx]

Recon is expected in this within the next couple of hours based on an 1800Z/2PM EDT NHC plan.

 I see what appear to be two spins, both with convection near them: the larger one out ~150 miles north of the coast and a small one ~75 miles SSE of the larger one and ~75 miles N of the coast.

[Normandy]

The vort max further norther is the one I would watch.  Seems to be more dominant

[Master of Disaster]

There has got to be a closed circulation under that blob. 

 

 

 

[Normandy]

Me thinks we get Danielle out of this.  its well organized enough right now and has a lot of time over water

[Ed, snow and hurricane fan]

Just now, Master of Disaster said:

There has got to be a closed circulation under that blob. 

 

 

 

Or more than 1 competing center Fujiwara-ing around a mean center of circulation, the weaker one getting closer to the stronger one until it is absorbed.  A K and I storm, give or take a letter, one was a hurricane, one was a TS, Fujiwara with the stronger one shearing the weaker one, until they became one.  My Google Fu is off on the names and year.  I think it is what happens when competing LLCs are present until one center becomes dominant.  The stronger one moves less, MLC location is important as well, land disruption (Guadalupe or one of the small volcanic islands) of Dorian destroyed the LLC and allowed the weak LLC under the MLC to become dominant, accelerating the intensification process.

[Floydbuster]

Looks great. 

[WxWatcher007]

Recon is in the air and en route to Invest 99L.

[WxWatcher007]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Aug 19 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Southwestern Gulf of Mexico:
Satellite imagery indicates that showers and thunderstorms 
associated with the broad low pressure area over the southwestern 
Gulf of Mexico and the Bay of Campeche continue to become better 
organized.  Environmental conditions appear favorable for 
additional development, and a tropical depression could form later 
today, tonight, or on Saturday while the system moves northwestward 
across the southwestern and western Gulf of Mexico.  However, by 
Saturday night, the system is expected to move inland over 
northeastern Mexico, which will end its chances of development. An 
Air Force Reserve Hurricane Hunter aircraft is currently enroute to 
investigate the system.  Interests along the northeastern coast of 
Mexico and the lower Texas coast should monitor the progress of 
this system.  Regardless of development, this system could bring 
locally heavy rains to portions of northeastern Mexico and southern 
Texas over the weekend.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Beven

[Normandy]

This one is screaming over performer to me.  Lets see what recon finds.

[WxWatcher007]

Recon has descended. Will be in the Invest soon and we'll get a much better sense of the structure. 

[WxWatcher007]

There are already some flagged and unflagged SFMR readings over 34kts. However, the sampling just began and we don't know the state of a potential LLC. 

[WxWatcher007]

Getting a lot of flagged reports now.

Too much rust from sitting idle during our dead period  

[WxWatcher007]

Still no evidence of a closed LLC so far from what I can see, but it's still fairly early. Probably going to be good enough for at least a PTC designation though.