WxWatcher007

Tropical Storm Danny Tropical Cyclone Update NWS National Hurricane Center Miami FL AL042021 305 PM EDT Mon Jun 28 2021 ...DEPRESSION STRENGTHENS TO A TROPICAL STORM... Doppler radar data from Charleston, South Carolina, along with preliminary data from an Air Force Reserve reconnaissance aircraft, indicate that the depression has strengthened and is now Tropical Storm Danny. The maximum sustained winds are estimated to be 40 mph (65 km/h) with higher gusts. A Weatherflow station at Folly Beach, South Carolina, recently reported a wind gust of 41 mph (66 km/h). SUMMARY OF 305 PM EDT...1905 UTC...INFORMATION ---------------------------------------------- LOCATION...32.2N 79.7W ABOUT 60 MI...95 KM ESE OF BEAUFORT SOUTH CAROLINA ABOUT 45 MI...70 KM SSE OF CHARLESTON SOUTH CAROLINA MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...WNW OR 325 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...1014 MB...29.94 INCHES $$ Forecaster Stewart

Tropical Storm Danny Tropical Cyclone Update NWS National Hurricane Center Miami FL AL042021 305 PM EDT Mon Jun 28 2021 ...DEPRESSION STRENGTHENS TO A TROPICAL STORM... Doppler radar data from Charleston, South Carolina, along with preliminary data from an Air Force Reserve reconnaissance aircraft, indicate that the depression has strengthened and is now Tropical Storm Danny. The maximum sustained winds are estimated to be 40 mph (65 km/h) with higher gusts. A Weatherflow station at Folly Beach, South Carolina, recently reported a wind gust of 41 mph (66 km/h). SUMMARY OF 305 PM EDT...1905 UTC...INFORMATION ---------------------------------------------- LOCATION...32.2N 79.7W ABOUT 60 MI...95 KM ESE OF BEAUFORT SOUTH CAROLINA ABOUT 45 MI...70 KM SSE OF CHARLESTON SOUTH CAROLINA MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...WNW OR 325 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...1014 MB...29.94 INCHES $$ Forecaster Stewart

That’ll work

That convective burst and continued organization has allowed for TD 4 to reach TS strength. Can really see the burst well on radar.

Can’t find recon data for the life of me, but TWC suggests that recon is finding TS winds near that convective burst around the center.

Tropical Depression Four Discussion Number 1 NWS National Hurricane Center Miami FL AL042021 1100 AM EDT Mon Jun 28 2021 The area of disturbed weather and associated low pressure system that the NHC has been tracking the past couple of days has developed into a tropical depression off the coast of South Carolina this morning. The inner-core cloud structure noted in high-resolution visible satellite imagery has continued to tighten up and deep convection with cloud top temperatures of -60 deg C have persisted northwest through southwest of the center, yielding a Dvorak shear pattern intensity estimate of 30 kt. This intensity estimate is consistent with overnight scatterometer surface wind data of 31-32 kt just north of the well-defined center. The initial motion estimate is 300/14 kt. The small tropical cyclone is expected to maintain a west-northwestward to northwestward motion for the next couple of days, resulting in landfall along the south-central coast of South Carolina later this evening. The small cyclone is expected to dissipate by 48 hours, if not sooner, when the system will be located over the southern Appalachian Mountains. The NHC track forecast lies close to the tightly packed GFS- and ECMWF-based Beta-Advection models due to the lack of any significant inner-core convection, which is allowing the cyclone to be steered more by the low-level flow rather than the deep-layer flow as depicted by the global and regional models. There is a narrow window of opportunity this afternoon for the depression to strengthen into a tropical storm before landfall occurs. During the next few hours, the small cyclone will be passing over the warmer Gulf Stream where sea-surface temperatures are around 28 deg C. In addition, as the outer wind field begins to interact with land, low-level frictional convergence along and just offshore should help to generate deep convection just prior to landfall, helping to spin up the wind field. The NHC forecast shows the system becoming a tropical storm before landfall, and as a result a tropical storm warning has been issued for a portion of the South Carolina coast. An Air Force Reserve Unit reconnaissance aircraft will investigate the system this afternoon beginning around 1800 UTC, providing more detailed information on the cyclone's intensity. Key Messages: 1. Heavy rainfall is possible from coastal southern South Carolina and Georgia, inland across the Piedmont of Georgia into northeast Alabama. Isolated flooding is possible across urban areas of the southern South Carolina and Georgia coasts. 2. Tropical-storm-force winds are expected across portions of the South Carolina coast late this afternoon and tonight where a Tropical Storm Warning is in effect. 3. Swells generated by the depression are expected to affect portions of the South Carolina coast this afternoon and tonight. These swells could cause life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 31.9N 78.3W 30 KT 35 MPH 12H 29/0000Z 32.8N 80.6W 35 KT 40 MPH...INLAND 24H 29/1200Z 34.2N 83.3W 20 KT 25 MPH...POST-TROP/INLAND 36H 30/0000Z 35.2N 85.6W 15 KT 15 MPH...POST-TROP/INLAND 48H 30/1200Z...DISSIPATED INLAND $$ Forecaster Stewart

Tropical Depression Four Discussion Number 1 NWS National Hurricane Center Miami FL AL042021 1100 AM EDT Mon Jun 28 2021 The area of disturbed weather and associated low pressure system that the NHC has been tracking the past couple of days has developed into a tropical depression off the coast of South Carolina this morning. The inner-core cloud structure noted in high-resolution visible satellite imagery has continued to tighten up and deep convection with cloud top temperatures of -60 deg C have persisted northwest through southwest of the center, yielding a Dvorak shear pattern intensity estimate of 30 kt. This intensity estimate is consistent with overnight scatterometer surface wind data of 31-32 kt just north of the well-defined center. The initial motion estimate is 300/14 kt. The small tropical cyclone is expected to maintain a west-northwestward to northwestward motion for the next couple of days, resulting in landfall along the south-central coast of South Carolina later this evening. The small cyclone is expected to dissipate by 48 hours, if not sooner, when the system will be located over the southern Appalachian Mountains. The NHC track forecast lies close to the tightly packed GFS- and ECMWF-based Beta-Advection models due to the lack of any significant inner-core convection, which is allowing the cyclone to be steered more by the low-level flow rather than the deep-layer flow as depicted by the global and regional models. There is a narrow window of opportunity this afternoon for the depression to strengthen into a tropical storm before landfall occurs. During the next few hours, the small cyclone will be passing over the warmer Gulf Stream where sea-surface temperatures are around 28 deg C. In addition, as the outer wind field begins to interact with land, low-level frictional convergence along and just offshore should help to generate deep convection just prior to landfall, helping to spin up the wind field. The NHC forecast shows the system becoming a tropical storm before landfall, and as a result a tropical storm warning has been issued for a portion of the South Carolina coast. An Air Force Reserve Unit reconnaissance aircraft will investigate the system this afternoon beginning around 1800 UTC, providing more detailed information on the cyclone's intensity. Key Messages: 1. Heavy rainfall is possible from coastal southern South Carolina and Georgia, inland across the Piedmont of Georgia into northeast Alabama. Isolated flooding is possible across urban areas of the southern South Carolina and Georgia coasts. 2. Tropical-storm-force winds are expected across portions of the South Carolina coast late this afternoon and tonight where a Tropical Storm Warning is in effect. 3. Swells generated by the depression are expected to affect portions of the South Carolina coast this afternoon and tonight. These swells could cause life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 31.9N 78.3W 30 KT 35 MPH 12H 29/0000Z 32.8N 80.6W 35 KT 40 MPH...INLAND 24H 29/1200Z 34.2N 83.3W 20 KT 25 MPH...POST-TROP/INLAND 36H 30/0000Z 35.2N 85.6W 15 KT 15 MPH...POST-TROP/INLAND 48H 30/1200Z...DISSIPATED INLAND $$ Forecaster Stewart

96L to be upgraded to TD Four at 11.

Well, it’s clearly organized enough with a well defined LLC. There’s just no big convection near the center. As the NHC said, any organization would bring advisories.

Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 PM EDT Sun Jun 27 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. A small low pressure system is located about 425 miles east-southeast of Savannah, Georgia. The associated shower and thunderstorm activity has become less organized since earlier this afternoon, becoming displaced to the northwest of the surface center due to strong upper-level winds. The low is forecast to move quickly west-northwestward at 15 to 20 mph, crossing over the warmer waters of the Gulf Stream Monday morning, and it has some potential to become a tropical depression or tropical storm before reaching the coast of Georgia or southern South Carolina by Monday evening. If the system becomes more organized overnight or on Monday, then tropical storm warnings could be required for a portion of the Georgia and South Carolina coasts with short notice. Regardless of development, a few inches of rain are possible along the immediate coasts of Georgia and southern South Carolina through Monday night. An Air Force Reserve Unit reconnaissance aircraft is scheduled to investigate the system Monday afternoon, if necessary. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 5 days...medium...50 percent.

Can’t recommend enough taking a cross country trip. The Tetons were phenomenal. Yes, that’s a snow squall obscuring mountains to the right.

It’s certainly unusually active in the basin right now. Aside from 96L, 95L is looking pretty decent today as the guidance tries to develop it (again) and the wave behind 95L is looking robust on guidance, at least right now. With the general steering environment, something that’s able to make it to the SW Atlantic or western Caribbean could make things interesting near or just after the holiday. Climo starts to open up in July for CV or MDR development, but it’s still early and we’re seeing robust waves coming through.

Thanks. Even as ENSO is looking more neutral, we're seeing a pretty active season so far with some signals that suggest the peak of the season is active.

The BOX discussion specifically said the upper level ridge was pushing 99th percentile of climo (edit: and the guidance has upper 90s possible for urban areas), so this doesn't strike me as run of the mill heat. Something can be hazardous without being historic and we know for heat a lot of it depends on the context you're living in. Most will be fine, some will not if they don't take it seriously or don't have access to AC/cooling.

This wasn't totally shocking. The guidance, while not explicitly forecasting TC genesis, had been trending stronger with the disturbance. Given the SST profile, and window for lower shear, we're seeing what could be some modest development. Let's see what the convective trends are over the next 12 hours as it approaches a better SST environment.

We've got a hot one! Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Sun Jun 27 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Satellite imagery and nearby buoy and ship observations indicate that a small low pressure system has formed about 500 miles east-southeast of the Georgia-South Carolina border. Surface pressures have begun to fall across the area, and showers and thunderstorms have recently become better organized. Some additional development of this system will be possible later today, and especially on Monday when the system will move across the warmer waters of the Gulf Stream, and a tropical depression could form before the system makes landfall along the southern U.S. coast. The low is expected to move westward today, and then west-northwestward at about 15 mph on Monday, reaching the coast of the southeastern United States by late Monday. An Air Force Reserve Unit reconnaissance aircraft is scheduled to investigate the system Monday afternoon, if necessary. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 5 days...medium...50 percent.

Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Sun Jun 27 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Satellite imagery and nearby buoy and ship observations indicate that a small low pressure system has formed about 500 miles east-southeast of the Georgia-South Carolina border. Surface pressures have begun to fall across the area, and showers and thunderstorms have recently become better organized. Some additional development of this system will be possible later today, and especially on Monday when the system will move across the warmer waters of the Gulf Stream, and a tropical depression could form before the system makes landfall along the southern U.S. coast. The low is expected to move westward today, and then west-northwestward at about 15 mph on Monday, reaching the coast of the southeastern United States by late Monday. An Air Force Reserve Unit reconnaissance aircraft is scheduled to investigate the system Monday afternoon, if necessary. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 5 days...medium...50 percent.

So let's talk 96L It's the latest in a line of homebrew region (in this case western Atlantic/off SE Coast) disturbances that is attempting to develop. It didn't come out of nowhere. As I usually say, if you are only following surface depictions on the models for TC genesis, you are missing a lot. There were signals that we'd see a robust disturbance (but short of an actual TC) for days. The trend has been stronger in the most recent runs. I like looking at 850mb vorticity. As you'll see below, the last 8 runs have been more robust with the disturbance's vorticity, which is key to TC genesis. But of course, there's more to it than that (though having some spin is essential). Let's take a look at SSTs. As @George BM noted, they've been warming quite nicely, even as temps near the coastline are a bit below normal currently. Having a sufficiently warm SST profile, a pocket of lower wind shear, and marginal moisture aloft has allowed for some gradual organization of 96L. In fact, it actually looks pretty good at the moment, with a low level circulation developing and convection firing near it. Consistent convection near the center would substantially raise the odds of some weak development, and that looks like a decent bet as the system passes near the Gulf Stream tonight/tomorrow. That said, there are some key environmental factors that strike against too much development. First is the dry air that is near the coast. While adequate, a more moist environment would be good for convection to fire. The other thing is shear. This disturbance is impacted by a nearby upper level low, and while it's in a pocket of lower shear now, there could be increasing shear near the coast. That's something to watch. The other thing is time. While there are conditions close to the coast that make TC genesis generally more favorable, the flip side is that anything that develops has a small window to intensify. That's good for the people of the coast of course. Overall, the signals, while weak, were there with this one. I think given what we're seeing on satellite right now, we have a fragile invest that is attempting tropical cyclone genesis.

The area of disturbed wx off the SE coast has been designated Invest 96L

Just designated as 96L. Homebrew

Probably not a lot of time to pop, but homebrew has been hot the last two years

Latest GFS throwing out a 99 at Hartford on Wednesday. This heat wave could be an over performer. Let’s crack 100

Happy birthday!