WxWatcher007

Wow. This weekend might have been one of the most fascinating tracking periods I've seen in years. Today looks nothing like we thought it would just 48 hours ago. Above, you will see all three systems we're watching. Tropical Storm Fred near Florida, Tropical Depression Grace just south of DR/Haiti, and Tropical Depression Eight in the central Atlantic. Let's start with a look at the basin. For now, all three are situated in areas of light to moderate shear. That has allowed each to develop, though each have handled shear differently. Fred is likely organizing or intensifying on final approach, while Grace has failed to take advantage of a low shear environment to do the same. TD Eight has been steady state since developing quickly yesterday, but has managed to continue firing convection and morning visible shows the center trying to relocate under the convection. For each, SSTs and TCHP have not been an issue. Let's start with Fred, the most imminent threat to the US. Tropical Storm Fred After a near fatal encounter with DR/Haiti and Cuba, Fred is back from the dead and is continuing a theme that we saw last season: organizing/intensifying near the coast. While some reorganization was expected, the overall appearance we see this morning wasn't really thought to be a possibility until about 24 hours ago. In addition, this weekend we saw substantial track changes, with center reformations and stationary movements forcing track shifts from the west coast of Florida to the Florida state line, and back toward the Panhandle. These shifts are highly unusual IMO, especially within 24-48 hours. Although Fred is expected to weaken quickly after landfall later on Monday, the uptick in organization, and eastward shift, has potential implications downstream. As it gets absorbed by a trough, that will bring flooding rains to the SE and potentially heavy rains further north. I'm not entirely sure the rainfall distribution will carry that deep inland, but it is certainly something to watch given the recent flash flooding in this region. In the end, Fred has become a respectable tropical cyclone. The same is looking increasingly possible for Grace, which to date has been the "dud" of the season. Tropical Depression Grace Grace has failed to meet virtually all expectations so far, and it is easy to see why, at least with regard to intensity. The early morning IR once again finds Grace to be disorganized, even in the face of relatively light shear. What could have been an intensifying system heading into DR/Haiti is a mess, with an elongated LLC that took days to develop, disorganized convection, and little indication that anything is changing. This, however, has caused truly massive changes in the track forecast and makes both intensity and track forecasts moving forward low confidence. This was the track for Grace at 5am on Saturday. ...and here it is this morning...with additional changes likely... Between Grace being far weaker than anticipated and the massive Atlantic ridge not providing the weakness (thus far) to turn Grace on a more WNW heading, Grace is increasingly likely to miss the Greater Antilles altogether. What that could mean is a more favorable environment for organization, but the presence of shear is possible as well. This leads to the final area of interest: Tropical Depression Eight. Tropical Depression Eight TD 8 burst onto the scene as an area with 20% odds to develop into a tropical cyclone at 8pm on Saturday. By 11pm on Sunday it was our 8th tropical cyclone of the season. This one has been a bit of a surprise, though it should be noted the guidance did have a signal for something to develop. Normally, this wouldn't be anything for the US to even give a second thought, but let's recall the theme of the season so far: anomalously strong ridging. TD 8, although far off the US coast, is in a warm SST and relatively low shear environment (though you can clearly see the impact of shear here) and it has the influence of a strong ridge nearby. The result? A little more uncertainty than we'd normally see. Some of the guidance, led by the Euro/EPS, wants to show a closer approach by what should become Tropical Storm Henri. Now, that's an outlier at the moment IMO, as the general ideal would be that TD 8 makes a complete clockwise turn around the ridge and heads harmlessly out to sea. However, if the ridge is stronger than anticipated and/or TD 8 becomes a deeper system and more able to be steered by the strong westward flow that in part is keeping Grace on this unexpected westward heading, it could be come an East Coast threat. You see this on a few of the EPS ensemble members. Emphasis on few. I think the smart money is on TD 8 never getting particularly close to the US, but given the anomalous ridging, and favorable environment for at least the next 24 hours to intensify, this might be something to watch if it becomes stronger than anticipated. We haven't reached August 20 yet, and the basin is about as hot as it can get. Indications are that the favorable window will remain open for the foreseeable future, further enhanced by the climatological peak of the season. Buckle up, folks. We're just getting started.

Stand by for a long tropical post

It looks like Fred is making an attempt at organizing/intensifying once again. Radar out of northern Florida shows the center once again trying to wrap convection around and increased velocities around the apparent center. IR shows what seems to be Fred's best appearance yet. If the center can stay under the convection and the convection wrap around, this could make a run at a minimal hurricane. Either way, this is likely to be a big rainmaker for a good part of the region.

What an incredible turn of events in the last 48 hours for Grace. When the weekend started I never imagined I'd be starting my Monday looking at a potential Mexico landfall and Grace avoiding virtually all land until then.

@GaWx this one is a little more interesting this morning, right? For now at least? I took a look at the EPS and there were certainly a few interesting members. Looks like most go OTS, but with a stronger system perhaps we get a further west push. NHC has really highlighted how uncertain a forecast this one is at D4 & D5. In fact, looking deeper at the EPS, the ones that do develop TD 8 do make it more of an EC threat. Interesting.

Yep--looks like the center got shunted a little SW per the VDM

Latest VDM Product: Air Force Vortex Message (URNT12 KNHC)Transmitted: 16th day of the month at 1:55ZAgency: United States Air ForceAircraft: Lockheed WC-130J Hercules with reg. number AF97-5305Storm Name: FredStorm Number & Year: 06 in 2021 (flight in the North Atlantic basin)Mission Number: 14Observation Number: 11 ( See all messages of this type for this mission. )A. Time of Center Fix: 16th day of the month at 1:30:10ZB. Center Fix Coordinates: 26.98N 86.05WB. Center Fix Location: 230 statute miles (371 km) to the WSW (253°) from Tampa, FL, USA.C. Minimum Height at Standard Level: 1,461m (4,793ft) at 850mbD. Minimum Sea Level Pressure: 1001mb (29.56 inHg)E. Dropsonde Surface Wind at Center: From 160° at 22kts (From the SSE at 25mph)F. Eye Character: Not AvailableG. Eye Shape: Not AvailableH. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 40kts (46.0mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 67 nautical miles (77 statute miles) to the NE (44°) of center fix at 1:09:30ZJ. Maximum Flight Level Wind Inbound: From 107° at 44kts (From the ESE at 50.6mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 62 nautical miles (71 statute miles) to the NE (43°) of center fix at 1:11:00ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 34kts (39.1mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 6 nautical miles to the W (272°) of center fix at 1:32:00ZN. Maximum Flight Level Wind Outbound: From 13° at 30kts (From the NNE at 34.5mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 6 nautical miles to the W (272°) of center fix at 1:32:00ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 16°C (61°F) at a pressure alt. of 1,522m (4,993ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 1,525m (5,003ft)R. Dewpoint Temp (collected at same location as temp inside eye): 15°C (59°F)R. Sea Surface Temp (collected at same location as temp inside eye): Not AvailableS. Fix Determined By: Penetration, Wind, Pressure and TemperatureS. Fix Level: 850mbT. Navigational Fix Accuracy: 0.02 nautical milesT. Meteorological Accuracy: 2 nautical milesRemarks Section: Maximum Flight Level Wind: 62kts (~ 71.3mph) which was observed 95 nautical miles (109 statute miles) to the E (94°) from the flight level center at 0:22:00Z

Not much change on that center pass.

Yeah, it’s still getting sheared a bit so getting right up under the convection is difficult, but the burst near the center (what looks like a curved band) and prior pressure drop are illustrative of an organizing phase IMO. We’ll see if that’s actually the case on the next pass.

Ah—yeah that went over my head lol

Huh? Fred is absolutely a TS per recon data. Grace though has basically been an sharp wave from the recon flight yesterday to the recon flight that just ended.

Definitely on an upswing intensity wise. Good FL wind spikes on the eastern side of the system. Some of those are probably convection/burst related, but we weren’t seeing those before.

The latest VDM for Fred Product: Air Force Vortex Message (URNT12 KNHC)Transmitted: 15th day of the month at 23:57ZAgency: United States Air Force Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5305 Storm Name: FredStorm Number & Year: 06 in 2021 (flight in the North Atlantic basin)Mission Number: 14Observation Number: 05 ( See all messages of this type for this mission. )A. Time of Center Fix: 15th day of the month at 23:28:10ZB. Center Fix Coordinates: 27.09N 85.69WB. Center Fix Location: 207 statute miles (333 km) to the WSW (253°) from Tampa, FL, USA.C. Minimum Height at Standard Level: 1,432m (4,698ft) at 850mbD. Minimum Sea Level Pressure: 1000mb (29.53 inHg)E. Dropsonde Surface Wind at Center: From 85° at 4kts (From the E at 5mph)F. Eye Character: Not AvailableG. Eye Shape: Not AvailableH. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 35kts (40.3mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 65 nautical miles (75 statute miles) to the WNW (301°) of center fix at 23:06:00ZJ. Maximum Flight Level Wind Inbound: From 78° at 32kts (From the ENE at 36.8mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 67 nautical miles (77 statute miles) to the WNW (301°) of center fix at 23:05:30ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 38kts (43.7mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 65 nautical miles (75 statute miles) to the SE (130°) of center fix at 23:50:30ZN. Maximum Flight Level Wind Outbound: From 206° at 35kts (From the SSW at 40.3mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 67 nautical miles (77 statute miles) to the SE (130°) of center fix at 23:51:00ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,521m (4,990ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,526m (5,007ft)R. Dewpoint Temp & Sea Surface Temp: Not AvailableS. Fix Determined By: Penetration, Wind, Pressure and TemperatureS. Fix Levels (surface & flight level centers within 5nm of each other): Surface and 850mbT. Navigational Fix Accuracy: 0.02 nautical milesT. Meteorological Accuracy: 0.75 nautical milesRemarks Section: Maximum Flight Level Wind: 35kts (~ 40.3mph) which was observed 67 nautical miles (77 statute miles) to the SE (130°) from the flight level center at 23:51:00Z

Not expecting a ton but this one has flown under the radar. Advisories likely by 11pm. Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 PM EDT Sun Aug 15 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Storm Fred, located over the east-central Gulf of Mexico, and on Tropical Depression Grace, located about 100 miles south-southeast of the Dominican Republic. 1. Satellite imagery and radar data from Bermuda indicate that showers and thunderstorms associated with a small but well-defined area of low pressure located northeast of Bermuda have continued to become better organized during the past few hours. If this trend continues, advisories will likely be initiated on a new tropical depression later tonight. The system is forecast to move slowly toward the south or southwest during the next day or so, and then turn westward on Tuesday, passing near or just east and south of Bermuda. Interests in Bermuda should monitor the progress of this system, and a Tropical Storm Watch could be required for that island tonight. * Formation chance through 48 hours...high...90 percent. * Formation chance through 5 days...high...90 percent. Forecaster Zelinsky

Great image grab. It’s trying hard to develop an inner core. If it can wrap all the way around and close off, the rate of intensification could increase.

Advisories on that likely tonight at 11. That’s basically a TD on satellite.

Confirmed pressure drop to 1000mb in center. Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)Transmitted: 15th day of the month at 23:40ZAgency: United States Air Force Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5305 Storm Name: FredStorm Number: 06 (flight in the North Atlantic basin)Mission Number: 14Observation Number: 06 ( See all messages of this type for this mission. )Part A... Date: Near the closest hour of 23Z on the 15th day of the month Highest Mandatory Level For Which Wind Was Reported: 850mb Coordinates: 27.1N 85.7W Location: 207 statute miles (334 km) to the WSW (253°) from Tampa, FL, USA. Marsden Square: 081 ( About ) Surface and Standard Isobaric Surfaces Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed 1000mb -3m (-10 ft) Other data not available. 925mb 686m (2,251 ft) 23.8°C (74.8°F) 21.9°C (71°F) 170° (from the S) 3 knots (3 mph) 850mb 1,431m (4,695 ft) 24.6°C (76.3°F) About 15°C (59°F) 20° (from the NNE) 12 knots (14 mph) Information About Radiosonde: - Launch Time: 23:28Z - About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction. Remarks Section... Dropsonde Location: Dropped in center. Highest altitude where wind was reported: - Location: 27.11N 85.68W - Time: 23:28:27Z Lowest altitude where wind was reported: - Location: 27.11N 85.68W - Time: 23:30:42Z Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding): - Wind Direction: 115° (from the ESE) - Wind Speed: 4 knots (5 mph) Deep Layer Mean Wind (average wind over the depth of the sounding): - Wind Direction: 45° (from the NE) - Wind Speed: 2 knots (2 mph) - Depth of Sounding: From 844mb to 999mb Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding: - Lowest 150m: 155 gpm - 5 gpm (509 geo. feet - 16 geo. feet) - Wind Direction: 95° (from the E) - Wind Speed: 3 knots (3 mph) Sounding Software Version: AEV 30404

Was just about to post. Pretty interesting drop. Would like to see what’s happening NE of the center.

Diving deeper into recon—I’m not sure if the NHC does anything at 8pm as they may want to make sure this isn’t a blip, but recon data suggests this is a TS with a closed LLC and multiple uncontaminated FL and SFMR reports confirming minimal TS winds.

Fred isn’t the strongest system ever but I’m impressed by how it has gotten itself off the mat. I expected it to an extent, but it’s really holding tough in the center in the face of moderate shear. Wind is one thing, but there’s a serious flash flooding threat for parts of the SE as this makes its way inland.

I was out while Fred was in the grave but I’m back now!

This is an open discussion IMO. Red tag or not your analytical posts should have a basis in fact/observation. I don’t think anyone should be above critique. How else would we learn anything? Anyway, recon is finally finding a LLC, albeit weak.

Surprised nobody posted. Will likely be a TD soon. Special Tropical Weather Outlook NWS National Hurricane Center Miami FL 500 PM EDT Sun Aug 15 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: Special Tropical Weather Outlook issued to updated the discussion of the low-pressure system northeast of Bermuda. The National Hurricane Center is issuing advisories on Tropical Storm Fred, located over the east-central Gulf of Mexico, and on Tropical Depression Grace, located over the northeastern Caribbean Sea a couple of hundred miles east-southeast of the Dominican Republic. 1. Updated: Satellite imagery indicates that shower and thunderstorm activity has become better organized this afternoon in association with a small but well-defined area of low pressure located about 160 miles northeast of Bermuda. Environmental conditions appear conducive for continued development, and if these development trends continue, a tropical depression could form tonight while the low moves slowly to the south or south-southwest at about 5 mph, near or to the east of Bermuda. By Tuesday, upper-level winds are forecast to become less conducive for tropical cyclone formation. Interests in Bermuda should monitor the progress of this system, and a Tropical Storm Watch could be required for that island later tonight. * Formation chance through 48 hours...high...70 percent. * Formation chance through 5 days...high...70 percent. Forecaster Brennan/Brown

Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Sun Aug 15 2021 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on recently re-designated Tropical Storm Fred, located over the east-central Gulf of Mexico, and on Tropical Storm Grace, located over the northeastern Caribbean Sea just to the south of Puerto Rico. 1. A small but well-defined low pressure system located about 175 miles northeast of Bermuda continues to produce disorganized shower and thunderstorm activity. Environmental conditions appear conducive for some development of this low during the next couple of days, and a tropical depression could form while it moves slowly to the south or south-southwest at about 5 mph, near or to the east of Bermuda. By Tuesday, upper-level winds are forecast to become less conducive for tropical cyclone formation. Interests in Bermuda should monitor the progress of this system during the next few days. * Formation chance through 48 hours...medium...40 percent. * Formation chance through 5 days...medium...40 percent. Forecaster Berg

Could be. It’s still sheared but it’s looking better structurally and it’s over some of the warmest water in the basin.