WxWatcher007

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.

Wow, 94L looks much better than when I made the post 8 hours ago. Convection looks like it’s trying to organize around a more consolidated center. Impressive move toward genesis this morning.

Alright, after about a month, it's time to talk tropics seriously again. First--let's take a look at the basin. In the last month, we've seen quite a bit of warming, which is typical, and with El Nino highly unlikely, the peak of the season has strong signals to see continued reduced shear that favors an active peak, which I personally classify between August 20 and October 20 (note--that's what I base my annual peak season forecast off of). July and early August are times for the basin to simmer, and simmer it did. It's not as warm as last season, which is why I am likely to base the peak as shy of hyperactive, but for another year, conditions thermally look to be most robust near the US coast and in the homebrew region. Below are a few images from the latest CSU hurricane season forecast, which I think are helpful in providing an additional picture of where the basin is with regard to signals for the coming peak. Above average, but short of hyperactive. Note the extreme drop in shear that led to the historic 2020 peak we saw in September and October. As we approach the 2021 peak, the basin is waking up. We're moving into a favorable MJO phase, and enhancement we're seeing that has moved the EPAC into an active period is making its way toward the Atlantic. After a few misfires (Invests 91L, 92L, and I suspect 93L), the Atlantic Basin has produced an area of interest that I believe has a better than even chance of some development. Designated as 94L less than 24 hours ago, I've been watching this little wave at the western edge of a monsoonal trough as guidance had an oscillating signal on whether development could come from it over the last half week or so. An objective assessment would reveal that this invest isn't particularly special. Vorticity is just decent, the convection is disorganized, and the system is small, which makes it prone to disruptions that could kill it before it ever tries to get off the ground. Although the shear looks minimal for the immediate path ahead, big challenges remain. First, you have dry air that is lurking. The image below is a mid level water vapor snapshot which shows all of the invests within the monsoon trough have effectively been starved of convection, which, of course, aids greatly in lowering pressures and creating an organizational feedback loop (for lack of a better term) within a center of low pressure. If that wasn't enough, then you have the Greater Antilles, which the latest GFS envisions a collision course with Haiti/DR and Cuba. So why am I even posting about this little critter then? Well, because TC genesis is neither linear nor static. Like Elsa, a poor environment in one part of the Atlantic doesn't necessarily prevent genesis or development in another. Sometimes you just have to survive. That's just what we've seen in some of the recent guidance. Although there are serious questions about how sheared anything would be as it approaches the US due to PV streamer (upper level low), the guidance while bouncing around seems to be giving 94L a greater chance of some minor development. There's actually not a lot to discuss seriously because there is so much that can change depending on track and potential development location, but for illustrative purposes only let's look at the 18z GFS, which has been fairly consistent with the general evolution of 94L. What do we see? Well, early on you see 94L trying to tighten up, and it looks like it does so in time just to hit PR or one of the other major islands. That causes obvious weakening, and there isn't a lot of development as the system is driven WNW by a strong ridge until a trough creates a weakness that pulls it up the coast. Still a lot to sort out there. It isn't until it is along the SE coast more significant development looks to take place. What does it all mean? At this point my takeaways are the following: 1) 94L looks to be the wave that has the best chance of coming out of the monsoon trough and developing into a weak system because it is in the best shear/moisture/SST environment. Development is not a guarantee, though. 2) Interaction with the Greater Antilles and a possible PV streamer will have a significant impact on the overall evolution of the system. 3) The presence of a strong ridge likely means this is driven WNW, and the timing and strength of an incoming trough will have an impact on whether 94L (should it develop) is able to (re)develop in the Gulf or off the East Coast. The ceiling for this one seems low, but we're tracking again. A lot to watch for as we get an appetizer before the main course arrives.

Posting the GFS is fine, people aren't really talking that much about it because there isn't a lot to really discuss IMO, but trying to attach hidden meaning to what F264 means is just a little much. Again, not trying to be rude, but I think you'll get more robust discussion if you keep your posts focused on the invest, the overall environment, and computer model runs.

Look, I mean this with all due respect...maybe throttle back on the posts a bit here bud. Meaningful discussion can't happen if posts don't make sense.

Dear God yes.

Not that I’m the fountain of knowledge lol but if you ever have questions please just ask.

12z EPS makes a pretty stark reversal as @Weather Will illustrates above, increases the signal for development.

Weenies galore While still obviously disorganized, both invests are holding their own and the signal for development of 94L has increased across guidance. We may finally have something real to track. Will be interesting to see if the overnight period aids in helping either organize a bit.

Hoping to do a 94L/basin overview at some point today.

Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Sun Aug 8 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: An elongated area of low pressure located several hundred miles east of the Windward Islands continues to produce disorganized showers and thunderstorms. Environmental conditions are expected to be favorable to support some gradual development over the next few days, and this system could become a tropical depression while it moves west-northwestward at 10 to 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles late Monday, and then move near the Virgin Islands and Puerto Rico on Tuesday, and near Hispaniola around the middle of this week. Interests in those areas should monitor the progress of this system, as it could bring locally heavy rainfall and gusty winds to portions of that area. * Formation chance through 48 hours...medium...40 percent. * Formation chance through 5 days...medium...50 percent. Showers and thunderstorms associated with an area of low pressure located over the tropical Atlantic about midway between the Cabo Verde Islands and the Lesser Antilles have diminished this morning. Although environmental conditions appear to be only marginally conducive for development, this system could still become a tropical depression later this week while it moves toward the west-southwest or west at around 10 mph. * Formation chance through 48 hours...low...30 percent. * Formation chance through 5 days...medium...40 percent. $$ Forecaster Brown