wxmx Posted August 17, 2012 Share Posted August 17, 2012 Very interesting trend continues. This looks like a threat to the islands. ... teaser just to hook Josh Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 ... teaser just to hook Josh About to go into the Caribbean. Fairly significant shift. Link to comment Share on other sites More sharing options...
wxmx Posted August 17, 2012 Share Posted August 17, 2012 I would be surprised if 94L recurved before 70W and also wouldn't be shocked if it doesn't recurve at all, on the 18z GFS. The center of the ridge is much farther west in comparison to the 12z GFS. No, ridging is strong....Caribbean cruiser on this run. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted August 17, 2012 Share Posted August 17, 2012 Hawt. Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 Hawt. Ever do an islands chase? Strong hurricane in the Caribbean. 90 knots right after that. Link to comment Share on other sites More sharing options...
thewxmann Posted August 17, 2012 Share Posted August 17, 2012 I am not completely surprised by the Caribbean solution... if 94L moves in tandem with the mid-level ridge to the north of it, I don't see it cutting through the ridge. Link to comment Share on other sites More sharing options...
Riptide Posted August 17, 2012 Share Posted August 17, 2012 No, ridging is strong....Caribbean cruiser on this run. There is a weakness at 80W, it's still going to try to come out of Caribbean. Link to comment Share on other sites More sharing options...
andyhb Posted August 17, 2012 Share Posted August 17, 2012 That looks...interesting. Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 Looks like 90-100 knots in the Caribbean. Weakness sees to be tugging this WNW a bit. Link to comment Share on other sites More sharing options...
andyhb Posted August 17, 2012 Share Posted August 17, 2012 Looks like 90-100 knots in the Caribbean. Weakness sees to be tugging this WNW a bit. Probably would be quite the hit to the Lesser Antilles. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted August 17, 2012 Share Posted August 17, 2012 Ever do an islands chase? I'll wait for it on the W end of the Caribbean, thank you. P.S. You never told me how you liked my Ernie video. Link to comment Share on other sites More sharing options...
kwt Posted August 17, 2012 Share Posted August 17, 2012 Looks like it'll hook up through Hispaniola on this run, it is lifting up but much more realistic than the previous abrupt turns from the previous GFS runs. Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 17, 2012 Share Posted August 17, 2012 More a modelling question, what changed in 6 hours as far as the initialization? Looks like only ~20% of the 12Z ensembles got the Northernmost Lesser Antilles? Not to mention why this is faster Westward than the Euro... Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 I'll wait for it on the W end of the Caribbean, thank you. P.S. You never told me how you liked my Ernie video. I thought the coordination you had with Scott was amazing, and that put you in the best possible spot for the storm. The footage was very impressive and the best I have seen in the Caribbean since 2007. Major props to you both. 18z GFS plucks this out of the Caribbean by 192 hours. Looks like a NW movement... SNE Wave watching anyone? Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 More a modelling question, what changed in 6 hours as far as the initialization? Looks like only ~20% of the 12Z ensembles got the Northernmost Lesser Antilles? Not to mention why this is faster Westward than the Euro... Ensembles were pretty clearly split at 12z 18z OP just took the southern extreme. We'll have to see if any other runs/models catch this, or if this was just a flash in the pan. Link to comment Share on other sites More sharing options...
kwt Posted August 17, 2012 Share Posted August 17, 2012 The interesting thing is the ECM is also not that different, the GFS is further west but the general trend out to 180hrs is very similar and timing is similar as well. Given the models have been trending west and have been speeding up the system, I'm confident this is not just fish-fodder this time round...18z GFS pulls a David out to 192hrs... Link to comment Share on other sites More sharing options...
thewxmann Posted August 17, 2012 Share Posted August 17, 2012 Past 192, it does an Edouard. Lol gets pretty close to Cape Cod. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted August 17, 2012 Share Posted August 17, 2012 I thought the coordination you had with Scott was amazing, and that put you in the best possible spot for the storm. The footage was very impressive and the best I have seen in the Caribbean since 2007. Major props to you both. Thanks. You were such a big part of the thread, I was curious to hear your post-mortem thoughts. 18z GFS plucks this out of the Caribbean by 192 hours. Looks like a NW movement... Still, it's way W compared with previous runs, and so the trend is great. Link to comment Share on other sites More sharing options...
icebreaker5221 Posted August 17, 2012 Share Posted August 17, 2012 Looks like the mid-Atlantic ridge at 18Z was analyzed quite a bit stronger than progged by the 12Z GFS. I'm guessing some satellite radiances were assimilated with warmer mi-level temps than forecasted. Link to comment Share on other sites More sharing options...
Riptide Posted August 17, 2012 Share Posted August 17, 2012 Past 192, it does an Edouard. Lol gets pretty close to Cape Cod. Not that it matters but the 18z GFS parallels 94L much closer to the east coast than Edouard. The track is essentially centered between the tracks of Irene and Edouard. Link to comment Share on other sites More sharing options...
phil882 Posted August 17, 2012 Share Posted August 17, 2012 I'm also growing a little bit more confident in the further south track this evening. The models (both the GFS/ECMWF) once again did horrible with the forecast position of the AEW when it exited off the African coast yesterday. Alan Brammer, another UAlbany student, has put together an excellent Dprog/Dt (model prog vs. model time) looper that will allow you to look at previous runs and compare them in time to the most recent model cycle. http://www.atmos.alb...r/GFS_forecast/ The typical bias in the models is for systems to be too slow and too far north in the East Atlantic. This is due to the poor handeling of mid-level ridging in the East Atlantic. The reason why the models don't really handle mid-level ridging well in the East Atlantic is because of their limited understanding of aerosols in the atmosphere. This is a particularly important factor off the African coast because of the Saharan Air Layer. While SAL is often linked to weakening TCs due to dry air intrusions, SAL also helps to warm the mid-column of the atmosphere (due to the absorption of radiation by the tiny dust particles). The end result is a stronger mid-level ridge due to the increased heights. Stronger mid-level ridges don't only keep TCs on a more leftward track, they also increase the forward speed. Without a proper understanding of aerosols in our global models, they almost habitually underestimate the strength of the mid-level ridging. Back to the animation above. Just look at this self correction the GFS has made the last several days. From day 4 to day 1.5, we see the model has been shifting Invest 94L further west (red X) with time and has been significantly increasing the forward speed. Notice how in contrast, Gordon (blue X) undergoes shifts, but not in any one particular direction, just the typical model uncertainty but no bias in any one particular direction. This indicates that is likely not a mid-latitude feature that is driving this shift in the mid-level ridging, but its a radiative process that is being underestimated in the modeling. Link to comment Share on other sites More sharing options...
phil882 Posted August 17, 2012 Share Posted August 17, 2012 Looks like the mid-Atlantic ridge at 18Z was analyzed quite a bit stronger than progged by the 12Z GFS. I'm guessing some satellite radiances were assimilated with warmer mi-level temps than forecasted. Bingo! Again its a large bias in the global models in the medium range due to improper aerosol handeling. In fact, I'm not totally sure if there are parameterizations for aerosols in any of the global models currently to account for their impacts on the atmosphere. That might be something that dtk can answer much better than I Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 17, 2012 Share Posted August 17, 2012 Ensembles are even farther west in the long term. Have to see if this is a trend during the 00z suite. AN AREA OF DISTURBED WEATHER ASSOCIATED WITH A TROPICAL WAVE IS LOCATED WELL SOUTH OF THE CAPE VERDE ISLANDS. SOME SLOW DEVELOPMENT IS POSSIBLE DURING THE NEXT FEW DAYS AS THIS SYSTEM MOVES TOWARD THE WEST AT 15 TO 20 MPH. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOUR Link to comment Share on other sites More sharing options...
CUmet Posted August 18, 2012 Share Posted August 18, 2012 I too am becoming increasingly confident that this will at least threaten the Lesser Antilles. The ridge to the north is pretty strong (>591 dm at 500 mb, >321 dm at 700 mb), and the ridge axis is pretty far south, located between 20-25 degrees north. This type of strong, suppressed ridge in the Central-East Atlantic is really effective at suppressing TC tracks. I doubt we'll see much, if any, latitude gain at least until 94L reaches 50W, if not later. The slow organization of the system also supports a more suppressed track. It goes without saying that the modeled intensities by both the GFS and ECMWF are quite impressive. While I expect organization to be rather slow over the next few days, this thing could really take off once it develops a good inner core as it approaches the islands. Link to comment Share on other sites More sharing options...
thewxmann Posted August 18, 2012 Share Posted August 18, 2012 0Z GFS similar to 18Z with a powerful hurricane striking the Lesser Antilles and PR. Subsequently splits the uprights between EC and Bermuda and recurves. Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 18, 2012 Share Posted August 18, 2012 00z GFS ensembles Link to comment Share on other sites More sharing options...
Riptide Posted August 18, 2012 Share Posted August 18, 2012 00z GFS ensembles It appears that most ensemble members are west of the OP? Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 18, 2012 Share Posted August 18, 2012 Looks like the storm specific models are catching on to a more westerly tack. Average track for 00z Link to comment Share on other sites More sharing options...
HurricaneJosh Posted August 18, 2012 Share Posted August 18, 2012 Nice. I'm liking some of these trends. Link to comment Share on other sites More sharing options...
phil882 Posted August 18, 2012 Share Posted August 18, 2012 0Z GFS similar to 18Z with a powerful hurricane striking the Lesser Antilles and PR. Subsequently splits the uprights between EC and Bermuda and recurves. I take anything beyond 120 hours in most of the models with a huge grain of salt. The trough over the southeastern US at 120 hours is actually lifting out, so its a little bit perplexing why the ridge is weakening at the same time over the Greater Antilles. That could perhaps be due to a mid-level llc associated with a TUTT, but that is difficult to forecast the proper position many days in advance. The end story is that there is still plenty of time to watch as Invest 94L slowly gets better organized. Link to comment Share on other sites More sharing options...
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