wxsmwhrms Posted September 8, 2011 Share Posted September 8, 2011 OK, that makes sense-- thanks. If the Euro/UKMET solution ends up "winning", around when would you expect it to cross the coast-- approximately? The EC has it crossing the coast around midnight Sunday night. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 8, 2011 Author Share Posted September 8, 2011 Looking much better this afternoon-- with the convection now apparently encircling the center (which is below 20N): Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted September 8, 2011 Share Posted September 8, 2011 18z GFS backed off from the prior runs of today. Link to comment Share on other sites More sharing options...
wxmx Posted September 8, 2011 Share Posted September 8, 2011 18z GFS backed off from the prior runs of today. Not only it backed off, it's now the southern outlier, with LF just south of 20N... this will bring big changes in the 11pm Advisory, faster and farther south...LF around Tampico on day 4, 85kts Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 8, 2011 Author Share Posted September 8, 2011 Not only it backed off, it's now the southern outlier, with LF just south of 20N... this will bring big changes in the 11pm Advisory, faster and farther south...LF around Tampico on day 4, 85kts So like Monday night-ish? Link to comment Share on other sites More sharing options...
wxmx Posted September 8, 2011 Share Posted September 8, 2011 So like Monday night-ish? I was forecasting the 11pm Advisory... I think it might be Monday morning, around Tampico, 90-100 kts Link to comment Share on other sites More sharing options...
OHweather Posted September 8, 2011 Share Posted September 8, 2011 Tropical Storm Nate Forecast/discussion 1: Tropical storm Nate's satellite appearance has only changed slightly since this morning, with the appearance of a sheared tropical cyclone evident with the center nearly exposed on the northeast edge of an area of deep convection. A recent microwave pass and air-force recon confirm this, with the center clearly displaced from the somewhat banded convection to the southwest of the center. Nate is nearly stationary at this time. Nate's track forecast is interesting. At the moment,ridging is in place to the north and to the east of the cyclone, allowing for very little movement. The current motion estimate from the NHC advisory is a SSE drift at about 2 knots. Over the next couple of days, most models attempt to drift the upper low associated with Lee's remnants farther south into the Ohio/Tennessee Valleys, weakening ridging to the north of Nate. However, ridging should remain in place over the Caribbean to the east of the storm, allowing for a slight increase in forward motion, generally to the north, in the near term. How far north Nate can get in the near term will be key, as the troughing from Lee's remnants will only get as far south as the central Gulf of Mexico. For example, the 12z GFS has Nate moving north tonight at a few knots faster than the ECM, and in a few days has Nate far enough north that ridging cannot build back to the north as quickly when Lee's remnants fill and move east, which would allow Nate to get north into the central Gulf and possibly threaten the northern Gulf coast as the GFS shows. However, the ECM does not bring Nate as far north nearly as quickly in the near term, and in the end begins to lift the trough over the southern/eastern US before Nate can get caught in the accelerated flow on the southern edge of the trough. This allows ridging to build back in north of Nate, allowing the cyclone to turn to the west and make landfall near Tampico Mexico in about 72 hours. Out of the 12z guidance, the CMC, NOGAPS, UKMET and ECM ensembles all agreed with this scenario. The GEFS mean was not as far north as the op GFS, but did not bring Nate inland as far south or as fast as the aforementioned guidance. ATCF track guidance agrees with this track forecast fairly well, however many models are slower than all of the globals (excluding the GFS), however many of these same ATCF models are GFS based. Given this, will ride the 12z ECM/ECM ensembles hard for this forecast, and will give the GFS and GFS based models little weight. Will show landfall near Tampico Monday morning. As for the intensity forecast, Nate is currently dealing with some northeasterly shear. However, an upper level anti-cyclone is forecasted to build over the storm over the next 12-24 hours, causing the shear that is already decreasing to become favorable for further development. The 12z GFS and ECM models both showed Nate deepening steadily from Friday morning through Sunday. Nate is over fairly warm sea surface temperatures and will move overfairly high heat content waters over the next couple of days. While there is some pretty dry air to the northwest of Nate, it should become less of a problem as shear relaxes. Given this, will show steady intensification through landfall. Will follow the ATCF guidance closely (a tad stronger than the middle of the road), as most models show steady intensification through landfall. Nate still has to become vertically aligned and work out some dry air before it can explosively develop, so will not show rapid intensification in the forecast. Forecast track/intensity: Initial...19.7N, 92.3W...60 knots, TS 24 hours (18z Friday)...20.2N, 92.3W...70 knots, Cat 1 48 hours (18z Saturday)...21.7N, 93.8W...80 knots, Cat 1 72 hours (18z Sunday)...22.1N, 95.7W...90 knots, Cat 2 96 hours (18z Monday)...22.0N, 97.9W...85 knots, Cat 2...Inland. Link to comment Share on other sites More sharing options...
wxmx Posted September 8, 2011 Share Posted September 8, 2011 The table is set, shear is pretty low below 24N .We'll probably have a period of RI in the next 2 days Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 The 7 pm CDT advisory has the cyclone essentially stationary over the SE corner of the Bay of Campeche. Link to comment Share on other sites More sharing options...
wxmx Posted September 9, 2011 Share Posted September 9, 2011 Nice blowup just south of the center. Link to comment Share on other sites More sharing options...
wxsmwhrms Posted September 9, 2011 Share Posted September 9, 2011 I don't mean to get off on a big tangent here, but just a quick comment on how the run to run changes with this system with ALL the models shows just how unpredictable the atmosphere can truly be and how sensitive to apparently small changes. It's a wonder we ever get it right - computer modeling has come a long way in my 25 some odd years in the field, Modelers are the unsung heroes of meteorology. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 I don't mean to get off on a big tangent here, but just a quick comment on how the run to run changes with this system with ALL the models shows just how unpredictable the atmosphere can truly be and how sensitive to apparently small changes. It's a wonder we ever get it right - computer modeling has come a long way in my 25 some odd years in the field, Modelers are the unsung heroes of meteorology. Totally. And I've noticed it really is an art to 1) know which model is getting the best handle on specific system and 2) distinguish real trends from the typical "windshield wiping". Just when you think you know, you get faked out. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 9, 2011 Share Posted September 9, 2011 I don't mean to get off on a big tangent here, but just a quick comment on how the run to run changes with this system with ALL the models shows just how unpredictable the atmosphere can truly be and how sensitive to apparently small changes. It's a wonder we ever get it right - computer modeling has come a long way in my 25 some odd years in the field, Modelers are the unsung heroes of meteorology. Outstanding post and I strongly agree with you. Link to comment Share on other sites More sharing options...
wxsmwhrms Posted September 9, 2011 Share Posted September 9, 2011 Totally. And I've noticed it really is an art to 1) know which model is getting the best handle on specific system and 2) distinguish real trends from the typical "windshield wiping". Just when you think you know, you get faked out. Tell me about it. I like to think I have gotten decent at it over the years, but systems like this can be a pain with so many things to take into account. I am really impressed by some of the "younger" folks like Phil, wxmx, and Cheeznado who use things like SOI trends to help them with model diagnosis. I have to be honest, that is something that I have zero experience at, and it's one of the reasons I participate on this board. I learn a lot. Outstanding post and I strongly agree with you. Thanks - I guess I should also say just computer scientists in general are unsung heroes of meteorology. The advances in computing have made such a huge difference to the field of meteorology. Link to comment Share on other sites More sharing options...
phlwx Posted September 9, 2011 Share Posted September 9, 2011 I don't mean to get off on a big tangent here, but just a quick comment on how the run to run changes with this system with ALL the models shows just how unpredictable the atmosphere can truly be and how sensitive to apparently small changes. It's a wonder we ever get it right - computer modeling has come a long way in my 25 some odd years in the field, Modelers are the unsung heroes of meteorology. Here here...and with Lee locally those models still did a very very good job despite being off only 50-75 miles with the placement of heavy rains. 3 days out...that's pretty damn good and well within margin of error. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Looks like some banding is starting to build in towards the center for the first time. Will this herald some nighttime intensification? Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Totally-- I felt like he made it just to see my reaction. The cool think to watch tonight is how the inner core presentation evolves. Microwave suggests that Nate is getting better organized, and convection is wrapping into the center for the first time. Could see a nice inner core develop in the overnight hours now that the shear appears to be decreasing. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 The cool think to watch tonight is how the inner core presentation evolves. Microwave suggests that Nate is getting better organized, and convection is wrapping into the center for the first time. Could see a nice inner core develop in the overnight hours now that the shear appears to be decreasing Yeah, it's definitely improving. Looks much better than yesterday. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Yeah, it's definitely improving. Looks much better than yesterday. Or even earlier today for that matter... you can see with the expanding outflow on IR that the shear has decreased rather dramatically. CIMSS had a nice corridor of <5 knot shear that pretty much follows very similarly to where a lot of the Global Models are projecting Nate's track. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Meanwhile the 00z Early Model suite has come in, and they are way south! In fact most barely get the storm above 20N. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 Meanwhile the 00z Early Model suite has come in, and they are way south! In fact most barely get the storm above 20N. Wow-- those tracks would kinda suck, actually! Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Wow-- those tracks would kinda suck, actually! Yea Its been kind of in the back of my mind the whole time that if this thing doesn't gain much latitude in the next 24-48 hours, there is nothing that will allow it to and it would essentially just start the W to WSW motion early. Its worth nothing that a lot of the models in that suite are heavily influenced by the GFS, so perhaps they are just playing follow the leader from the 18z GFS. Link to comment Share on other sites More sharing options...
wxsmwhrms Posted September 9, 2011 Share Posted September 9, 2011 It is definitely looking better - convective band showing a more curved appearance and improving outflow. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 It is definitely looking better - convective band showing a more curved appearance and improving outflow. For sure-- and it's also revealing itself to be quite small. A definite microcane in the making. I just hope it gains some latitude, or this thing isn't going to live up to its potential! Link to comment Share on other sites More sharing options...
wxsmwhrms Posted September 9, 2011 Share Posted September 9, 2011 Yea Its been kind of in the back of my mind the whole time that if this think doesn't gain much latitude in the next 24-48 hours, there is nothing that will allow it to and it would essentially just start the W to WSW motion early. Its worth nothing that a lot of the models in that suite are heavily influenced by the GFS, so perhaps they are just playing follow the leader from the 18z GFS. How about that GFDL? At 06Z this morning it had a cat 2/3 making city at Morgan City, LA, and the 18Z run doesn't even get it N of 20N moving it into Mexico. The HWRF has a similar track to the EC and UK but slower (LF not until day 5), and I am starting to wonder if that slower idea doesn't have some merit. There certainly is very little motion still, and the steering currents only slowly strengthen. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 For sure-- and it's also revealing itself to be quite small. A definite microcane in the making. I just hope it gains some latitude, or this thing isn't going to live up to its potential! That isn't to say it still can't strengthen though of it remains at a low latitude. Karl last year never made it above 20N and we still got a mid-range cat 3 out of it. Glass half full. Link to comment Share on other sites More sharing options...
dan88 Posted September 9, 2011 Share Posted September 9, 2011 New advisory peaks at 90kt and dropping to 85kt before landfall, gets to 22.0N Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 New advisory peaks at 90kt and dropping to 85kt before landfall, gets to 22.0N Looks like we will have a bullish Stewart discussion tonight. Link to comment Share on other sites More sharing options...
thewxmann Posted September 9, 2011 Share Posted September 9, 2011 Meanwhile the 00z Early Model suite has come in, and they are way south! In fact most barely get the storm above 20N. Ughh. Ugly. Get this thing north so it can have more room to intensify. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 9, 2011 Author Share Posted September 9, 2011 New advisory peaks at 90kt and dropping to 85kt before landfall, gets to 22.0N Yep-- and landfall seems to be early Monday. But this is interesting: THERE HAS BEEN A LARGE MODEL CHANGE FROM SIX HOURS AGO...WITH THE GFS/GFDL/HWRF MODELS NOW HAVING A GENERAL WESTWARD TRACK TOWARD MAINLAND MEXICO DUE TO THE CYCLONE BEING TRAPPED BENEATH A NARROW RIDGE OVER THE NORTHERN GULF OF MEXICO. NATE IS FARTHER SOUTH THAN EXPECTED YESTERDAY...SO THE LIKELIHOOD OF A MORE POLEWARD TRACK AHEAD OF THE NEXT TROUGH OVER THE CENTRAL UNITED STATES HAS DIMINISHED. THUS THE NHC FORECAST IS SHIFTED WELL TO THE LEFT AT THIS TIME...BUT BASICALLY ALL RELIABLE MODELS ARE STILL FARTHER TO THE SOUTH. IF CURRENT TRENDS CONTINUE...THE FORECAST WOULD HAVE TO BE ADJUSTED SOUTHWESTWARD AT A LATER TIME. Link to comment Share on other sites More sharing options...
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