WxWatcher007

Recon en route now to see if this has actually become a tropical cyclone. Still looks like it's trying to get its act together, but certainly wouldn't be surprised if they found a closed circulation.

Interesting thread. I agree that it's possible for this to slide further west into the Gulf, but I don't think it's likely. The operational guidance (for those that are lurking, I mean the GFS, Euro, etc.) in general has been consistent and more important--has stayed within the range of track possibilities outlined by both the ensembles (GEFS, EPS). The huge caveat here though is we're tracking a Potential Tropical Cyclone. TC genesis has not officially occurred yet, though recon is en route right now to confirm. Once we have more data and a well-defined center, we can have greater confidence in eventual track. We've seen situations before where you get a center a little further north or south and it can make a difference in intensity which can make a difference in track. I think one thing for this region to watch, is the sharpness of the curve. I think there's a pretty high chance this ridge pushes this into the Gulf, but there's a split in what happens after that. Does this end up being a sharper recurve that brings remnants to the region or does the GFS have the right idea and the ridge actually pushes this almost due north and washes it out quickly. I think that's entirely up in the air at this point. GEFS EPS While we're at it, once again I want to note the signal on both ensembles for a follow up wave right after this one...

Surprised nobody posted the GFS. It might be a blip, but it really intensifies the system in the Gulf. Looks like a hurricane landfall in the Big Bend area verbatim. Looks like the potential shear vector is further west in the Gulf and that’s enough for this to quickly organize. Just one run, but interesting..

Caveats galore for the HWRF when there isn't a well-defined center.

Wasn’t it Isaias that split the Mona pass last year and became a hurricane while doing it?

I love me some HWRF, I just don't like looking at it before something is well-defined and closed off. I do think it has a higher ceiling than this time yesterday, but as you said, a lot of moving pieces with this one. These Caribbean crossers always seem to be a challenge. Totally agree about having a stronger vortex. I think we'll get one of modest strength before PR, so then it becomes a question (to me at least) of 1) how damaged, if at all, it becomes crossing land and 2) does the shear actually pan out? We've seen cases where shear isn't quite what we thought (in both directions) and it has had a significant impact on the eventual evolution of a tropical system. Finally, what will happen with this ridge? It seems like there's agreement that this ridge holds until the Bahamas, but then there's divergence on the guidance in when a more pronounced turn occurs. I think the 12z EPS does a good job with individual members highlighting a fairly wide variety of possible track outcomes. A lot of interesting pieces to watch.

I think it would survive (barely), but it'd be hard pressed to recover, especially if it gets sheared after passing the area.

Finally, here's the discussion. As @Windspeed was mentioning, those towers going up in PTC 6 right now could have an impact on the track, as a center positioned a little further north could allow for the vortex to miss some land masses. It does look like the environment in the western Atlantic could keep things in check if that were to happen, but we'll need to see what the trends are with projected shear in the next few days. Of course, this could also hit everything given the ridge to the north steering it WNW. Potential Tropical Cyclone Six Discussion Number 1 NWS National Hurricane Center Miami FL AL062021 500 PM AST Mon Aug 09 2021 Deep convection associated with the area of low pressure located northeast of Barbados has continued to consolidate this afternoon, with several bands noted in both satellite and radar data from Barbados and Martinique. ASCAT data from this morning revealed a sharp trough axis, but the system lacked a well-defined circulation. However, recent visible satellite imagery hints that a better defined center may be forming just southwest of the primary convective mass. These trends suggest the system is likely to become a tropical depression or storm tonight or Tuesday when it moves near the Lesser Antilles and into the eastern Caribbean. Therefore, advisories are being initiated on the system in order to issue Tropical Storm Watches for portions of the Lesser Antilles, the U.S. Virgin Islands, Puerto Rico and parts of the Dominican Republic. Since the system is still in its formative stage the initial motion estimate is a somewhat uncertain 290/13 kt. A mid-tropospheric ridge anchored over the western Atlantic should steer the system west-northwestward through the forecast period. Although there is high confidence in the overall steering pattern over the next several days, there is lower than normal confidence in the details of the track forecast, especially in the short-range due to the lack of a well-defined center. Exactly where the center forms will have some downstream implications on the exact forecast track, especially across the eastern Caribbean. Regardless of the exact track, locally heavy rainfall and gusty winds are expected to spread across portions of the Leeward Islands, the Virgin Islands, Puerto Rico, and the Dominican Republic over the next day or two, hence the need for Tropical Storm Watches for portions of those areas. The disturbance is embedded within an area of low vertical wind shear and SSTs of around 28C. These conditions favor additional development, but the occasional entrainment of dry mid-level air located just west of the system is likely to prevent more rapid organization. By Wednesday, the system is likely to be near Hispaniola, where subtle differences in the forecast track could have large implications on the intensity of the storm later this week. A track directly over Hispaniola would likely significantly disrupt the circulation, while a track more poleward of the island could allow the system to stay more intact. An additional caveat beyond 48 hours is that vertical wind shear out of the southwest may also increase, which could limit the intensity after the system moves past Hispaniola, although uncertainty exists in how much the shear will increase given differences between the more favorable ECMWF and less favorable GFS model solutions. The NHC intensity forecast brings the system up to a 45 kt tropical storm before potential land interaction with Hispaniola and afterwards is conservative given the possibility of additional land interaction and less favorable environmental conditions towards the end of the forecast period. KEY MESSAGES: 1. The system is forecast to become a tropical storm as it moves through the Lesser Antilles tonight. Tropical storm conditions are possible in portions of the southern Leeward Islands tonight and Tuesday and in the Virgin Islands and Puerto Rico beginning Tuesday afternoon, and in the Dominican Republic by Wednesday. 2. Heavy rainfall could lead to flash, urban, and small stream flooding and potential mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southeastern portions of Puerto Rico. 3. There is a risk of wind and rainfall impacts in portions of Hispaniola, the Turks and Caicos, the southeastern Bahamas, and Cuba later this week, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system's progress and updates to the forecast. 4. Interests in the remainder of the Bahamas and Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there by late this week or this weekend given the uncertainty in the long-range forecast. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 14.2N 59.2W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 10/0600Z 15.4N 61.4W 35 KT 40 MPH...TROPICAL CYCLONE 24H 10/1800Z 16.8N 64.5W 40 KT 45 MPH 36H 11/0600Z 17.9N 67.3W 45 KT 50 MPH 48H 11/1800Z 19.2N 70.2W 35 KT 40 MPH...INLAND 60H 12/0600Z 20.3N 72.8W 35 KT 40 MPH...OVER WATER 72H 12/1800Z 21.1N 75.0W 35 KT 40 MPH 96H 13/1800Z 22.8N 78.8W 40 KT 45 MPH 120H 14/1800Z 24.5N 82.0W 40 KT 45 MPH $$ Forecaster Brown/Papin

First cone

First cone

Expected to become a tropical storm tonight. BULLETIN Potential Tropical Cyclone Six Advisory Number 1 NWS National Hurricane Center Miami FL AL062021 500 PM AST Mon Aug 09 2021 ...DISTURBANCE APPROACHING THE LESSER ANTILLES FORECAST TO BECOME A TROPICAL STORM TONIGHT... ...TROPICAL STORM WATCHES ISSUED... SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...14.2N 59.2W ABOUT 165 MI...260 KM ESE OF DOMINICA ABOUT 205 MI...330 KM SE OF GUADELOUPE MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 15 MPH...24 KM/H MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of France has been issued a Tropical Storm Watch for Guadeloupe and Martinique. The government of Barbados has been issued a Tropical Storm Watch for Dominica. The government of the Dominican Republic has issued a Tropical Storm Watch for the Dominican Republic from Punta Palenque eastward along the southern coast of the island and the entire northern coast to the Dominican Republic/Haiti border. A Tropical Storm Watch has been issued for the U.S. Virgin Islands and Puerto Rico, including Culebra and Vieques. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Watch is in effect for... * Martinique and Guadeloupe * Dominica * Puerto Rico, including Culebra and Vieques * U.S. Virgin Islands * Dominican Republic on the south coast from Punta Palenque eastward and the entire northern coast to the Dominican Republic/Haiti border. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 500 PM AST (2100 UTC), the disturbance was centered near latitude 14.2 North, longitude 59.2 West. The system is moving toward the west-northwest near 15 mph (24 km/h) and this general motion is expected to continue during the next few days. On the forecast track, the system is expected to move through a portion of the southern Leeward Islands tonight, pass near or over the U.S. Virgin Islands and Puerto Rico late Tuesday and Tuesday night, and near or over Hispaniola on Wednesday. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Gradual strengthening is forecast during the next 48 hours and the disturbance is expected to become a tropical storm tonight. * Formation chance through 48 hours...high...80 percent. * Formation chance through 5 days...high...80 percent. The estimated minimum central pressure is 1010 mb (29.83 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Potential Tropical Cyclone Six can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT1, WMO header WTNT41 KNHC and on the web at www.hurricanes.gov/graphics_at1.shtml?key_messages. RAINFALL: The potential tropical cyclone is expected to produce the following rainfall amounts: Over the Leeward Islands, Virgin Islands, and Puerto Rico...2 to 4 inches, with isolated amounts of 6 inches. This rainfall could lead to flash, urban, and small stream flooding and potential mudslides across the U.S. Virgin Islands and Puerto Rico. Over the northern Windward Islands...1 to 3 inches. Over the Dominican Republic...3 to 6 inches. WIND: Tropical storm conditions are possible within the watch area in the Lesser Antilles tonight, and are also possible within the watch area in the U.S. Virgin Islands and Puerto Rico beginning Tuesday afternoon. Tropical storm conditions are possible within the watch area in the Dominican Republic beginning early Wednesday. NEXT ADVISORY ------------- Next intermediate advisory at 800 PM AST. Next complete advisory at 1100 PM AST. $$ Forecaster Brown/Papin

I just saw the EPS. I think it should also be noted that there's potential on the other side of this system too. This really is just the leadoff of what should be an active period. With the steering pattern as it is, we are likely to see East Coast threats further in August if systems develop in the western MDR.

This is my refuge. Advisories forthcoming on PTC 6.

Good because I was starting to sweat my bold prediction from a few hours ago In all seriousness though the gradual organization has continued IMO this afternoon, even though it's not entirely closed off yet and still needs to fire more consistent convection.

The 12z Euro op keeps 94L away from the land interaction that the GFS has, but keeps it weak on its way to south Florida, shear looks to be the main culprit. It does try to organize a bit after crossing Florida, but not a lot of space to do much. Looks like a good rainmaker verbatim.

Something about hurricane force winds and SN+ just appeals to me

Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Mon Aug 9 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Showers and thunderstorms associated with the area of low pressure located about 100 miles east-northeast of Barbados continue to show signs of organization. However, recent satellite wind data indicates that the system currently lacks a well-defined center. Environmental conditions are expected to remain conducive for additional development, and a tropical depression is likely to form later today or tonight while the low moves west-northwestward at 10 to 15 mph. The disturbance is forecast to move through portions of the Lesser Antilles tonight, then move near the Virgin Islands and Puerto Rico on Tuesday, and Hispaniola on Wednesday. Tropical storm watches or warnings could be required this afternoon with shorter-than-normal lead times for portions of the Lesser Antilles, the Virgin Islands, and Puerto Rico. In addition, heavy rains and flooding are likely for the Leeward Islands, Virgin Islands, and Puerto Rico. Interests in those areas should monitor the progress of this system. * Formation chance through 48 hours...high...80 percent. * Formation chance through 5 days...high...80 percent.

One of these would be acceptable too

The thing about that GFS run (and it could be right) is that it basically achieves a landfall trifecta, with hits on Puerto Rico, the Dominican Republic, and Cuba before getting into the Gulf. Of course, that requires a pretty precise track, so the ensembles are still important here in understanding the envelope of possibilities right now. So far, everything looks weak and fairly disorganized.

Provided we don’t see a backslide in organization, I think we do see PTC or TD advisories at 5pm. TD would be harder to achieve as it’s not closed off yet and that could take a while longer.

Looking at the 12z guidance and that’s a heck of a ridge over the top of 94L. Certainly within the realm of possibility that whatever this ends up being (likely weak) lands in the eastern Gulf.

The overlays on that site are awesome.

Since I love everything that swirls in wx, take a look at this satellite image this morning.

Definitely making a run at TC genesis. It's in a low shear environment overall but look at those cloud tops getting blown away to the north. Shear isn't too far away. There's still a good bit of uncertainty over what this looks like when it gets to the western Atlantic.

After some steady organization over the last 24 hours, Invest 94L has made a marked shift toward TC genesis in the last 8 hours. Now, the NHC has 2-day and 5-day odds of development at 70%. The long term intensity forecast for 94L is uncertain due to potential land interaction but overall it looks like a system that is a threat to the Greater Antilles before making some kind of US approach as a ridge steers it WNW and trough induced weakness in the ridge in the later forecast period creates an opportunity for a curve of some kind. Whether that happens in the Gulf, or just off the SE Coast remains to be seen. Both the GEFS and EPS, which have struggled to keep a consistent signal until recently, have some type of evolution that looks similar to what I just described. I think it's also worth noting that while the GEFS has a less robust outlook for 94L, the operational model continues to be more "aggressive" with a minimal TS off the SE coast as early as this weekend. Let's track. Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 AM EDT Mon Aug 9 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Showers and thunderstorms have become more concentrated this morning in association with a low pressure system located about 150 miles east of Barbados. Environmental conditions are expected to be conducive for additional development, and a tropical depression is likely to form later today or tonight while the low moves west-northwestward at 10 to 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles tonight, then move near the Virgin Islands and Puerto Rico on Tuesday, and be near Hispaniola around the middle of this week. Tropical storm watches or warnings could be required today with shorter-than-normal lead times for portions of the Lesser Antilles, the Virgin Islands, and Puerto Rico. In addition, heavy rains and flooding are likely for the Leeward Islands, Virgin Islands, and Puerto Rico. Interests in those areas should monitor the progress of this system. * Formation chance through 48 hours...high...70 percent. * Formation chance through 5 days...high...70 percent.