WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 Not seeing anything particularly impressive so far but the western side still needs to be examined. Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 Looks like the LLC might be right under the intense convection. I have a feeling we're gonna see some surprisingly big wind numbers when they find the center. Or... the system isn't even closed. lol. They'll investigate western region, I'm sure. Link to comment Share on other sites More sharing options...
cptcatz Posted August 14, 2021 Share Posted August 14, 2021 Why would they make that turn to the southeast? Wouldn't the wind directions point to the center being northwest of that turn? Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 The 12z HWRF just took a big swing left of previous runs and tracks Grace a good bit south of the Isle of Youth still on a due west track at hr 117. 1 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 9 minutes ago, cptcatz said: Why would they make that turn to the southeast? Wouldn't the wind directions point to the center being northwest of that turn? It’s not a bad idea to sample the broader circulation, and it could allow for a NE to SW pass later. 1 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 Latest dropsonde report says it was dropped in the center, but they haven’t sampled anything further west, which looks to be showing some organization on radar. Interesting. Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)Transmitted: 14th day of the month at 17:49ZAgency: National Oceanic and Atmospheric Administration (NOAA) Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF) Storm Name: GraceStorm Number: 07 (flight in the North Atlantic basin)Mission Number: 1Observation Number: 02 ( See all messages of this type for this mission. )Part A... Date: Near the closest hour of 18Z on the 14th day of the monthHighest Mandatory Level For Which Wind Was Reported: 850mbCoordinates: 15.7N 59.8WLocation: 109 statute miles (175 km) to the ENE (76°) from Roseau, Dominica.Marsden Square: 042 ( About ) Surface and Standard Isobaric Surfaces Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed 1014mb (29.95 inHg) Surface (Sea Level) 25.4°C (77.7°F) 23.9°C (75°F) 305° (from the NW) 2 knots (2 mph) 1000mb 120m (394 ft) 24.4°C (75.9°F) 23.7°C (75°F) 285° (from the WNW) 2 knots (2 mph) 925mb 804m (2,638 ft) 21.8°C (71.2°F) 19.2°C (67°F) 325° (from the NW) 3 knots (3 mph) 850mb 1,535m (5,036 ft) 18.2°C (64.8°F) 16.4°C (62°F) 85° (from the E) 5 knots (6 mph) Information About Radiosonde:- Launch Time: 17:34Z- 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: 15.74N 59.81W- Time: 17:34:15ZLowest altitude where wind was reported:- Location: 15.74N 59.82W- Time: 17:36:52ZMean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):- Wind Direction: 155° (from the SSE)- Wind Speed: 2 knots (2 mph)Deep Layer Mean Wind (average wind over the depth of the sounding):- Wind Direction: 90° (from the E)- Wind Speed: 3 knots (3 mph)- Depth of Sounding: From 841mb to 1012mbAverage Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:- Lowest 150m: 160 gpm - 10 gpm (525 geo. feet - 33 geo. feet)- Wind Direction: 290° (from the WNW)- Wind Speed: 2 knots (2 mph) Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 It’s not a bad idea to sample the broader circulation, and it could allow for a NE to SW pass later. Looks like they clearly flew through the old wave axis there, whether that leads into the broader circulation or eroded old broad one, whichever. Guess we'll just have to be patient and see what the MLC is like showing up on radar and whether that is a vortex down to the surface. 2 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 12z HWRF: Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 I really think that complex of convection (purple arrow) is merely a strong MCS that is not associated with the true low level vorticity that does appear to have some low level westerly flow on its south side (red arrow). That MCS will probably erode downstream. I am more interested in the subtle banding that appears to be forming near that true center. The steering flow should slow down some over night and perhaps this will allow Grace to organize further. As always, satellite and even radar can sometimes be a bit deceiving. Link to comment Share on other sites More sharing options...
Normandy Posted August 14, 2021 Share Posted August 14, 2021 Nailed it Windspeed. It looks like a squall line with the wake low tagging behind it. The low level flow to the south is also beginning to be tugged north as well. Seems to be developing nicely but slowly Link to comment Share on other sites More sharing options...
cptcatz Posted August 14, 2021 Share Posted August 14, 2021 Looks like recon is going home without going through the biggest convection?? Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 5 minutes ago, cptcatz said: Looks like recon is going home without going through the biggest convection?? Yep. We’ll have to wait for surface observations to confirm whatever is happening in the most intense convection. **shrug** Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 12z GEFS ensembles trended west. 1 Link to comment Share on other sites More sharing options...
cptcatz Posted August 14, 2021 Share Posted August 14, 2021 5 minutes ago, WxWatcher007 said: Yep. We’ll have to wait for surface observations to confirm whatever is happening in the most intense convection. **shrug** Looks like it's on a crash course for Antigua, should be getting good surface obs soon. Link to comment Share on other sites More sharing options...
Wannabehippie Posted August 14, 2021 Share Posted August 14, 2021 1 hour ago, Windspeed said: One is probably the LLC, the other the MLC, as there is a lot of shear going on. Link to comment Share on other sites More sharing options...
SnowenOutThere Posted August 14, 2021 Share Posted August 14, 2021 After looking at several posts about where the true center is I thought I would try to define where it is. In the green I think is where the true center is with the latest convection blowup, I think this because in the blue we can see where the banding spirals out of meaning the center would be where the green circle is. This is only a guess due to the "junk convection" in orange which obscures where the true center is exactly. Link to comment Share on other sites More sharing options...
NorthHillsWx Posted August 14, 2021 Share Posted August 14, 2021 Atlantic storms are just struggling this year. I’m sure it will change. Land interaction, dry air, moving too quickly, shear, anything that can hamper storm development has to this point 3 Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 Atlantic storms are just struggling this year. I’m sure it will change. Land interaction, dry air, moving too quickly, shear, anything that can hamper storm development has to this point To be fair, most Atlantic systems east of the Lesser Antilles struggle prior to the current climatological date. On top of that, both Fred and Elsa had significant interactions with the mountainous terrains of Hispaniola and Cuba besides the marginal atmospheric state. Fred has fared far worse than Elsa so far. Remains to be seen how Grace will evolve here in the short-term. But there really is a lot to be said about that August 20th date that Dr. William Gray harped about every season. Granted we do have earlybirds on occasion, but that is when the proverbial switch tends to flip on for the MDR. 1 Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 That 5pm AST track is not so graceful... Link to comment Share on other sites More sharing options...
cptcatz Posted August 14, 2021 Share Posted August 14, 2021 Interested to see what's happening in northern Guadalupe right now. Link to comment Share on other sites More sharing options...
hlcater Posted August 14, 2021 Share Posted August 14, 2021 Starting to wonder with the current degree of disorganization if a passage south of the greater antilles is moving into the picture. 24hr trends on ensembles seem to suggest so. For this to become reality, would need to see grace continue to struggle into tomorrow. In either case, the earlier runs with a strengthening storm managing to avoid at least hispaniola/cuba to the north seem a bit less likely today and models have been correcting south as a result. Link to comment Share on other sites More sharing options...
SluggerWx Posted August 14, 2021 Share Posted August 14, 2021 3 hours ago, Windspeed said: 12z HWRF: We're just north of there currently in Playa Mujeres. Latest HWRF has current location as almost a bullseye Thursday afternoon. Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 1 hour ago, Windspeed said: That 5pm AST track is not so graceful... 44 minutes ago, hlcater said: Starting to wonder with the current degree of disorganization if a passage south of the greater antilles is moving into the picture. 24hr trends on ensembles seem to suggest so. For this to become reality, would need to see grace continue to struggle into tomorrow. In either case, the earlier runs with a strengthening storm managing to avoid at least hispaniola/cuba to the north seem a bit less likely today and models have been correcting south as a result. Such a sensitive forecast. It looked like a more poleward solution was on the table when the 12z guidance initialized more organized, and now it’s all shifted well south but could change quickly if there’s a center reformation or greater organization. Big changes all in the span of a few hours. Fascinating stuff. Link to comment Share on other sites More sharing options...
Windspeed Posted August 14, 2021 Share Posted August 14, 2021 Flight engineer Nick Underwood giving explanation for their recent flight path through Grace: 2 Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 6 minutes ago, Windspeed said: Flight engineer Nick Underwood giving explanation for their recent flight path through Grace: That’s a simple explanation They had two radars on the flight so they would know. 1 Link to comment Share on other sites More sharing options...
cptcatz Posted August 14, 2021 Share Posted August 14, 2021 Can anyone explain what's going on with this structure? Will the storm drop one of these convection blobs or maybe will they start wrapping around each other and form an eye in the middle? Link to comment Share on other sites More sharing options...
WxWatcher007 Posted August 14, 2021 Author Share Posted August 14, 2021 Link to comment Share on other sites More sharing options...
Ed, snow and hurricane fan Posted August 14, 2021 Share Posted August 14, 2021 2 minutes ago, cptcatz said: Can anyone explain what's going on with this structure? Will the storm drop one of these convection blobs or maybe will they start wrapping around each other and form an eye in the middle? Those islands seem small, but Dorian, they destroyed the LLC which was SW of the MLC. On its own, might have taken days for them to align. Those islands helped Dorian organize by destroying the LLC so a new one could form. Not saying Cat 5 in the Bahamas. But the volcanoes on islands like Guadeloupe are big enough to disrupt weak surface circulations. Link to comment Share on other sites More sharing options...
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