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WxWatcher007

Tropical Storm Cristobal

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The NHC has designated the remnants of Tropical Storm Amanda as Invest 93L. There are 80% odds of development in the next 48 hours as the invest crosses into the southern Bay of Campeche (BOC). It will have a new name in the BOC, as Amanda dissipated before fully crossing into the broader Atlantic Basin. 

There was a fairly remarkable long range signal for development in early June as we saw a robust MJO/CCKW move toward the basin and the development of a CAG (Central American Gyre), which typically occurs at the beginning and end of the Atlantic hurricane season. 

Although guidance has signaled development for a while, there is still a fair amount of uncertainty on the eventual strength and land impact should development occur (I think it will)

As @Windspeed noted, although SSTs in the northern Gulf are somewhat marginal for supporting a higher end tropical system, the upper level pattern if timed right may be conducive for rather robust intensification. 

To me, there are a couple of things to track:

1. Does 93L manage to avoid significant land interaction as it develops in the southern BOC. If so, how much does that impact the ceiling for development?

2. What kind of weakness do we see in the ridging over the region, and how will troughing factor into the eventual steering pattern? 

3. Will a system as broad 93L be able to organize efficiently given its projected size?

There is still a lot to watch here between the eventual strength and track, but I do think we get a named system here. Already a pretty robust MLC and convection. 
 

Edited to add images

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Jun 1 2020

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

1. A large area of disturbed weather, associated with the remnants of 
eastern Pacific Tropical Storm Amanda, is located over the Yucatan 
peninsula of Mexico.  This disturbance is forecast to move 
northwestward over the southeastern portion of the Bay of Campeche 
later today or tonight where environmental conditions are expected 
to be conducive to support development, and a new tropical 
depression is likely to form within within the next day or so.  The 
system is then forecast to drift west or west-southwest over the 
southern Bay of Campeche through the middle of the week.  Interests 
along the coast of the Bay of Campeche should monitor the progress 
of this disturbance.  Regardless of tropical cyclone formation, 
heavy rainfall is likely to continue over portions of southern 
Mexico, Guatemala, El Salvador, Belize, and western Honduras during 
the next few days. For additional information on the rainfall 
threat, see products from your national meteorological service.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

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Based on current location and motion of Amanda's old mid-level vort, now 93L, the system may now exit further north off of the western shoreline of the Yucatan and not linger as long near or over the southern BOC shoreline. This may allow a future surface vort to form further away from the coastline and have an even longer period of time to organize versus previous ICON modeling, which was actually one of the more aggressive globals for intensification.

 

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I have to say I am quite impressed by both the convection and apparent organization over land. This is a pretty robust look and if we do continue to see this kind of structure we probably get quick development over the BOC. This is definitely one to watch closely in the Gulf. 

22520076.gif?0.22420610411337172

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The convective presentation may seem a bit worse on IR this afternoon, but I’d argue that’s deceiving. Looking at the visible loop you can see a robust low level circulation, though it also look decoupled from a mid level circulation further over land. 

The radar is perhaps the best evidence of a low level center. It is slowly edging over the shoreline and heading back over the BOC. It will be important to see how/if convection fires in that region as it takes advantage of 28-29 C SSTs.

202006011700.gif

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90% odds now. 
 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Jun 1 2020

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

Satellite imagery and radar observations from Mexico show that 
the area of disturbed weather centered near the west coast of the 
Yucatan peninsula is gradually becoming better organized.  The 
disturbance will move west-northwestward over the Bay of Campeche 
later this afternoon where environmental conditions are expected 
to be conducive to support development, and a tropical depression 
or storm is likely to form tonight or Tuesday.  The system is then 
forecast to drift westward or west-southwestward over the southern 
Bay of Campeche through the middle of the week.  Interests 
along the coast of the Bay of Campeche should monitor the progress 
of this disturbance as tropical storm watches or warnings could be 
required for a portion of this area later today or tonight. 
Regardless of tropical cyclone formation, heavy rainfall is likely 
to continue over portions of southern Mexico, Guatemala, El 
Salvador, Belize, and western Honduras during the next few days. 
For additional information on the rainfall threat, see products 
from your national meteorological service.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

$$
Forecaster Brown

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Operational guidance wants to shunt 93L down into Mexico, which would certainly complicate things as it’d remain trapped in the broader circulation of the CAG. It’s up in the air how the short to medium term track evolution shakes out.

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Operational guidance wants to shunt 93L down into Mexico, which would certainly complicate things as it’d remain trapped in the broader circulation of the CAG. It’s up in the air how the short to medium term track evolution shakes out.

How rapidly will 93L/potential Cristobal organize and intensify out over the BOC? As stated above, formation of a surface vort and its coupling to the MLC further north might buy more time for significant intensification -- which could allow the TC to stall, loop and detach from the overall flow around the CAG. The TC would then become susceptible to feel the weakness in the 500 hpa CONUS heights later in the week. However, a weaker system might fail to detach, ending back over Mexico (12z GFS & ECMWF). Interestingly, another secondary TC develops out of the eastern appendage of the CAG with interaction of WCARIB surface trough/wave that moves over the Yucatan on the ECMWF, which could hypothetically become Dolly. Too much uncertainty without knowing when and where our initial surface vort forms with 93L, and potential strength.
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44 minutes ago, Windspeed said:
1 hour ago, WxWatcher007 said:
Operational guidance wants to shunt 93L down into Mexico, which would certainly complicate things as it’d remain trapped in the broader circulation of the CAG. It’s up in the air how the short to medium term track evolution shakes out.

 

How rapidly will 93L/potential Cristobal organize and intensify out over the BOC? As stated above, formation of a surface vort and its coupling to the MLC further north might buy more time for significant intensification -- which could allow the TC to stall, loop and detach from the overall flow around the CAG. The TC would then become susceptible to feel the weakness in the 500 hpa CONUS heights later in the week. However, a weaker system might fail to detach, ending back over Mexico (12z GFS & ECMWF). Interestingly, another secondary TC develops out of the eastern appendage of the CAG with interaction of WCARIB surface trough/wave that moves over the Yucatan on the ECMWF, which could hypothetically become Dolly. Too much uncertainty without knowing when and where our initial surface vort forms with 93L, and potential strength.

It’s such an open question right now. Even the ensembles are split. What seems to be unambiguous however is that no matter if this remains a coherent TC or another spoke of the CAG develops, there is a named storm threat to the US Gulf Coast. 

Advisories on TD 3 to be initiated at 5pm. Welcome to the 2020 Atlantic hurricane season.

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Seems like a lot of land interaction and possibly some upwelling based on the next 3 to 4 days on that map IMO... let's see how it does in a few days

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4 minutes ago, yoda said:

Seems like a lot of land interaction and possibly some upwelling based on the next 3 to 4 days on that map IMO... let's see how it does in a few days

Yeah, this is a low confidence NHC forecast. I think any upwelling would be minimized by 1) the TCHP in the southern BOC, 2) reduced wind shear in that region over time, and 3) the topography of the BOC possibly enhancing organization.

Absent land interaction this is probably a low to mid end TS, which would have an important downstream impact. If it dissipates over land, that reduces the wind risk for the northern Gulf. Rain is probably going to be an issue either way. 

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BULLETIN
Tropical Depression Three Advisory Number   2
NWS National Hurricane Center Miami FL       AL032020
1000 PM CDT Mon Jun 01 2020

...DEPRESSION EXPECTED TO BRING HEAVY RAINFALL TO PORTIONS OF 
MEXICO AND CENTRAL AMERICA...


SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...19.6N 91.9W
ABOUT 95 MI...150 KM WSW OF CAMPECHE MEXICO
ABOUT 190 MI...305 KM ENE OF COATZACOALCOS MEXICO
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Campeche to Puerto de Veracruz

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1000 PM CDT (0300 UTC), the center of Tropical Depression Three
was located near latitude 19.6 North, longitude 91.9 West. The
depression is moving toward the west near 7 mph (11 km/h).
This heading at a slower forward speed is expected tonight. The
depression is forecast to turn west-southwestward or southward at a
even slower forward speed on Tuesday, and meander over the southern 
Bay of Campeche through late Wednesday.  On the forecast track, the
center of the cyclone is forecast to be near the coast of the
southern Bay of Campeche Tuesday night through Thursday.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Gradual strengthening is expected during the next couple of days 
and the depression is forecast to become a tropical storm
tonight or Tuesday.

The estimated minimum central pressure is 1005 mb (29.68 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Tropical Depression Three can be found in the
Tropical Cyclone Discussion under AWIPS header MIATCDAT3, WMO
header WTNT43 KNHC, and on the web at
www.hurricanes.gov/text/MIATCDAT3.shtml

RAINFALL:  Tropical Depression Three is expected to produce rain 
accumulations of 10 to 15 inches over parts of the Mexican states 
of Tabasco and Veracruz,  portions of Guatemala and the Yucatan 
Peninsula. This system is also expected to produce rain 
accumulations of 5 to 10 inches over parts of El Salvador and 
Honduras. Isolated maximum rainfall amounts of 20 inches are 
possible in the Mexican states of Tabasco, Veracruz, Chiapas and 
portions of Guatemala. This rainfall may produce life-threatening 
flash floods and mudslides.

WIND:  Tropical storm conditions are expected to first reach the
coast within the warning area Tuesday night.


NEXT ADVISORY
-------------
Next intermediate advisory at 100 AM CDT.
Next complete advisory at 400 AM CDT.

$$
Forecaster Beven

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Tropical Depression Three Discussion Number   2
NWS National Hurricane Center Miami FL       AL032020
1000 PM CDT Mon Jun 01 2020

Satellite imagery, along with radar and surface data from Mexico, 
indicate that the depression has changed little in organization or 
strength since the previous advisory.  There are a couple of small 
clusters of convection near the center, while the more concentrated 
convection is occurring in ragged bands well removed from the 
center.  The initial intensity remains 25 kt based on the surface 
data and continuity from the previous advisory.

The initial motion is now westward or 270/6.  The evolution of this 
system during the next several days remains quite uncertain.  The 
Canadian and UKMET models forecast the cyclone to make a slow 
counter-clockwise loop inside a larger gyre over Central America 
during the next 2-3 days, with the center moving near the coast of 
the Bay of Campeche.  This would be followed by a more northward 
motion with some increase in forward speed as a mid-/upper-level 
trough develops over the northern Gulf of Mexico.  On the other 
hand, the GFS and ECMWF show the depression turning southward and 
making landfall over the coast of Mexico in the next 24-36 h, 
followed by dissipation.  These two models subsequently develop a 
second low pressure area northwest of the Yucatan Peninsula at 
around 120 h due to the interaction of the aforementioned gyre and 
trough.  The new forecast track follows the previous forecast in 
showing TD-3 as being the system that moves northward across the 
Gulf.  However, the new track brings the center closer to the coast 
of Mexico and is slower to move it northward than in the previous 
advisory.  It should be noted, though, that in 5 days there could be 
a cyclone near the forecast point that is not actually TD-3.

In the current track forecast scenario, slow strengthening should 
occur during the next 24-48 h while the cyclone moves over the warm 
water of the Bay of Campeche in an environment of light to 
moderate shear.  After time, proximity to the Mexican coast should 
limit strengthening, and it is possible that the current forecast 
intensities could be generous.  The more northward motion near the 
end of the forecast period is likely to be accompanied by an 
increase in southerly shear, so only modest intensification is 
forecast during that time.  Overall, the new intensity forecast is 
similar to the previous forecast.  An alternative intensity 
forecast scenario is that the cyclone moves far enough inland over 
Mexico to dissipate completely in less than 5 days as forecast by 
the GFS and ECMWF.

Given the complexity of the situation, both the track and 
intensity forecasts are currently low confidence.  However, either 
of the current scenarios will result in widespread heavy rains over 
portions of southern Mexico and Central America.


Key Messages:

1. The depression is expected to bring heavy rainfall to portions of
southern Mexico, Guatemala, Honduras and El Salvador, which could
cause life-threatening flash flooding and mudslides. Refer to
products from your local weather office for more information.

2. Tropical storm conditions are expected along the coast of Mexico
where a tropical storm warning is in effect.

3. The system is forecast to begin moving northward across the Gulf
of Mexico later this week. However, it is too soon to specify the
location and timing of any potential impacts along the U.S. Gulf
Coast. Interests in these areas should monitor the progress of this
system through the week and ensure they have their hurricane plan in
place as we begin the season.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0300Z 19.6N  91.9W   25 KT  30 MPH
 12H  02/1200Z 19.6N  92.6W   30 KT  35 MPH
 24H  03/0000Z 19.2N  92.8W   35 KT  40 MPH
 36H  03/1200Z 18.8N  93.0W   40 KT  45 MPH
 48H  04/0000Z 18.6N  93.1W   45 KT  50 MPH
 60H  04/1200Z 18.5N  93.2W   45 KT  50 MPH
 72H  05/0000Z 18.5N  93.0W   45 KT  50 MPH
 96H  06/0000Z 19.5N  92.5W   45 KT  50 MPH
120H  07/0000Z 22.0N  91.5W   50 KT  60 MPH

$$
Forecaster Beven
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22 minutes ago, yoda said:

It should be noted, though, that in 5 days there could be a cyclone near the forecast point that is not actually TD-3.

I'm relatively new to hurricane tracking and understand how/why this can occur (mainly from watching Levi's video where he explains it so well), but still seems like a bizarre forecast.  Has this kind of thing been seen before by the NHC?

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Anyone else thinking that there will be a center re-location? That convection blob (possibly the mid-level remnants of Amanda) are really firing over the middle of the Yucatan Peninsula.

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14 minutes ago, Floydbuster said:

Anyone else thinking that there will be a center re-location? That convection blob (possibly the mid-level remnants of Amanda) are really firing over the middle of the Yucatan Peninsula.

I've been watching. I think it is likely, be interesting to see if convection keeps firing in that area.

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1 hour ago, cptcatz said:

I'm relatively new to hurricane tracking and understand how/why this can occur (mainly from watching Levi's video where he explains it so well), but still seems like a bizarre forecast.  Has this kind of thing been seen before by the NHC?

I can’t say I’ve seen that explicitly mentioned in a forecast. Goes to show how complicated a forecast this is. Also, welcome to tracking tropical! 

21 minutes ago, Floydbuster said:

Anyone else thinking that there will be a center re-location? That convection blob (possibly the mid-level remnants of Amanda) are really firing over the middle of the Yucatan Peninsula.

It’s possible. It looks pretty close to the center though, no? The center is pretty well defined, so unless that burst of convection persistent and is a robust mid level circulation it may be hard to pull the LLC under it. Radar looks decent. Loop looks a bit better than the single image.

202006020430.gif

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Anyone else thinking that there will be a center re-location? That convection blob (possibly the mid-level remnants of Amanda) are really firing over the middle of the Yucatan Peninsula.
Me

Sent from my LML212VL using Tapatalk

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TD 3 is looking better this morning, with intense convection beginning to fire near the center. NHC says recon will fly in later this morning. As for the eventual track, still highly uncertain. Additional recon data will be helpful. 00z Euro kept land interaction to a minimum and that had significant downstream impacts on the strength of the low. 

13562174.gif?0.5372215913348439

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This will be an interesting system.  It is certainly showing increased organization this morning.  The early visible loop shows the convective blob near the center.  The upper flow over the center is quite good, too.

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Recon has arrived and is descending into the system.

A quick look at their data seems to indicate an upgrade (as we expected) to TS status is likely at the 10am CDT update.

 

 

Edit for 10am advisory: No upgrade

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