Sunny and Warm Posted July 29, 2013 Share Posted July 29, 2013 having trouble editing the graph post, so I'll make comment here. As we've seen for days, the model members split into two camps, with the weaker versions taking a more westerly/southerly line into Cuba, and the stronger "Dorian" a more northerly track into FL. We should know by afternoon on Tuesday which is correct as the two scenarios separate sufficiently at that time. Link to comment Share on other sites More sharing options...
Ground Scouring Posted July 29, 2013 Share Posted July 29, 2013 Down to 40%: ZCZC MIATWOAT ALLTTAA00 KNHC DDHHMMTROPICAL WEATHER OUTLOOKNWS NATIONAL HURRICANE CENTER MIAMI FL800 AM EDT MON JUL 29 2013FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...1. A TROUGH OF LOW PRESSURE...ASSOCIATED WITH THE REMNANTS OF DORIAN...IS PRODUCING AN AREA OF CLOUDINESS AND DISORGANIZED THUNDERSTORMSA COUPLE OF HUNDRED MILES NORTH OF PUERTO RICO AND THE VIRGINISLANDS. THIS DISTURBANCE STILL DOES NOT APPEAR TO HAVE A CLOSEDLOW-LEVEL CIRCULATION...AND SURFACE PRESSURES REMAIN HIGH ACROSSTHE AREA. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE ONLYMARGINALLY CONDUCIVE FOR REGENERATION TO OCCUR...AND THIS SYSTEMHAS A MEDIUM CHANCE...40 PERCENT...OF BECOMING A TROPICAL CYCLONEDURING THE NEXT 48 HOURS AS IT MOVES WESTWARD TO WEST-NORTHWESTWARDAT 15 TO 20 MPH. THE DISTURBANCE IS EXPECTED TO CONTINUE PASSINGWELL TO THE NORTH OF PUERTO RICO TODAY...AND MOVE ACROSS THE TURKSAND CAICOS ISLANDS AND THE BAHAMAS ON TUESDAY AND WEDNESDAY. ANAIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT IS SCHEDULED TOINVESTIGATE THE DISTURBANCE THIS AFTERNOON...IF NECESSARY.ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEASFORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPSHEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THENEXT 48 HOURS.FORECASTER BERG Link to comment Share on other sites More sharing options...
Ground Scouring Posted July 29, 2013 Share Posted July 29, 2013 Interestingly, we have one dynamical model--the 06Z HWRF--that is now forecasting a hurricane nearing SW FL in five days. Up until this point there was no dynamical support for the more-aggressive statistical intensity models. Link to comment Share on other sites More sharing options...
Srain Posted July 29, 2013 Share Posted July 29, 2013 lol...The 06Z HWRF avoids Andros Island passes through the Florida Straights S of Key West, turns NW near the Marquesas Keys and develops into a Hurricane in the SE Gulf. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 Calm or variable winds several hours at San Juan, radar suggests nearly Earth stationary motion on cells closest to San Juan, but the near calm winds South of Zombie Dorian has been there for over a day (aircraft even found the occasional 3 knot or so West wind) and nothing has happened yet. But plenty of convection, and I'm always a rose colored glasses optimist. And there is nothing else in town, Atlantic tropics (I have some crazy Gulf speculation based on Euro in 9 and 10 days of a non-tropical origin system, but it is crazy) Steve has noted HWRF. I guess we shall see. But it has seemed, from past experience, globals usually outperform the HWRF, And Dorian is barely detectable in 850 mb vorticity fields or 700 mb height/wind/RH fields in a couple of days. Link to comment Share on other sites More sharing options...
Ground Scouring Posted July 29, 2013 Share Posted July 29, 2013 Stupid question: If ex-Dorian continues to generate this convection, would it still be able to counteract the influence of the TUTT, or has the TUTT already moved too far N for ex-Dorian's outflow to reduce net shear? Link to comment Share on other sites More sharing options...
CoastalWx Posted July 29, 2013 Share Posted July 29, 2013 12z intensity guidance looks a little more aggressive. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 12z intensity guidance looks a little more aggressive. Not being a smark aleck, but hasn't early cycle statistical guidance always been too enthusiastic with Dorian and its corpse? Link to comment Share on other sites More sharing options...
Srain Posted July 29, 2013 Share Posted July 29, 2013 12z intensity guidance looks a little more aggressive. The statistical guidance has been aggressive for a day or two. If we see a trend in the 12Z dynamical guidance, I'll believe that the 06Z HWRF is correct in 'sniffing' regeneration of Dorian. That said it does appear that deep convection has developed far better than we have seen in a few day. Hopefully RECON will offer clarity on 91L's future later this morning. Link to comment Share on other sites More sharing options...
Sunny and Warm Posted July 29, 2013 Share Posted July 29, 2013 Link to comment Share on other sites More sharing options...
Sunny and Warm Posted July 29, 2013 Share Posted July 29, 2013 The statistical guidance has been aggressive for a day or two. If we see a trend in the 12Z dynamical guidance, I'll believe that the 06Z HWRF is correct in 'sniffing' regeneration of Dorian. That said it does appear that deep convection has developed far better than we have seen in a few day. Hopefully RECON will offer clarity on 91L's future later this morning. still fighting some dry air and robust southerly shear Link to comment Share on other sites More sharing options...
CoastalWx Posted July 29, 2013 Share Posted July 29, 2013 Not being a smark aleck, but hasn't early cycle statistical guidance always been too enthusiastic with Dorian and its corpse? I don't know....was on break, but just noting the change from the previous cycle. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 I don't know....was on break, but just noting the change from the previous cycle. Well, as noted before on another thread, I have nothing against Florida, and what I might want has no bearing on the atmosphere, but I'd like Florida to avoid 8 years without a hurricane landfall sooner rather than later so I can relax and enjoy the entire season, and in the never ending battle to combat my super-weenie optimism, I may have been a touch anti-weenie. Over-compensation. By the inner weenie wins out every time. Sorry if I did come off as a smart aleck. Link to comment Share on other sites More sharing options...
icebreaker5221 Posted July 29, 2013 Share Posted July 29, 2013 Stupid question: If ex-Dorian continues to generate this convection, would it still be able to counteract the influence of the TUTT, or has the TUTT already moved too far N for ex-Dorian's outflow to reduce net shear? Looks like the TUTT and associated shear continue to retreat towards the northwest. 24 h tendencies from CIMSS suggest that this is occurring at about 2-3 degrees per day, which is slower than Dorian is currently moving. Although the TUTT is also lifting north, I don't see any way Dorian makes its way west without at least going through the southern periphery of the zone of higher shear. On the bright side, shear will weaken as the TUTT lifts out and conditions will improve considerably west of there - if there is still a Dorian to track. The statistical guidance has been aggressive for a day or two. If we see a trend in the 12Z dynamical guidance, I'll believe that the 06Z HWRF is correct in 'sniffing' regeneration of Dorian. That said it does appear that deep convection has developed far better than we have seen in a few day. Hopefully RECON will offer clarity on 91L's future later this morning. We've just passed the diurnal maximum. Dorian was looking ok yesterday at this time too. If the comeback is for real this time, Dorian will have to still look good 6-12 hrs from now. Link to comment Share on other sites More sharing options...
CoastalWx Posted July 29, 2013 Share Posted July 29, 2013 Well, as noted before on another thread, I have nothing against Florida, and what I might want has no bearing on the atmosphere, but I'd like Florida to avoid 8 years without a hurricane landfall sooner rather than later so I can relax and enjoy the entire season, and in the never ending battle to combat my super-weenie optimism, I may have been a touch anti-weenie. Over-compensation. By the inner weenie wins out every time. Sorry if I did come off as a smart aleck. No worries, I didn't take it like that at all. I agree to wait with the other guidance, but there was a shift when comparing the 06z guidance as well as better clustering. Link to comment Share on other sites More sharing options...
wxmeddler Posted July 29, 2013 Share Posted July 29, 2013 It might have just been able to build a convection bridge last night. Still waiting to see if DMIN strips it. Shear is very obvious. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 It looks like convection is trying to build a bit to the Southwest despite the shear to cover up the apparent low level vorticity max. (I don't want to say LLC, I think that would imply a closed low level center). Last frame of attached loop, a cell is going up very near where I think LL turning is maximized. New aircraft POD out, I see no mention of a canx today (and I don't think they should) and more flights tomorrow, if needed. Link to comment Share on other sites More sharing options...
Ground Scouring Posted July 29, 2013 Share Posted July 29, 2013 The LLV is rather clearly located at about 20.5°N 66.5°W; note the SW turning of the low-level clouds to the south, the S movement to the east, and the E movement due west. That means the LLV and the MLV are still badly dislocated due to strong southwesterly shear by the TUTT. Low-level ridging and easterly flow are still a bit too strong to allow slowing of the forward speed, so the system continues to struggle with the TUTT. The low-level vorticity maximum would then move, as it appears to be doing, S of due west and would be over the NE coast of Cuba in about two days. This fits with some of the models like the HWRF, the ECMWF, and the GFDL. Edit: As of 1445Z, the LLV may be attempting to relocate a bit farther NE. The low-level clouds to the S of the LLV appear to have shifted from SW to more of a WSW component, perhaps. If a center relocation closer to the MLV were to occur, and if new convection were to redevelop near the MLV, then the system might gain more time over water and pass just N of Cuba in about two days. It would also be a bit better equipped to withstand the shear. Link to comment Share on other sites More sharing options...
Amped Posted July 29, 2013 Share Posted July 29, 2013 The LLV is rather clearly located at about 20.5°N 66.5°W; note the SW turning of the low-level clouds to the south, the S movement to the east, and the E movement due west. That means the LLV and the MLV are still badly dislocated due to strong southwesterly shear by the TUTT. Low-level ridging and easterly flow are still a bit too strong to allow slowing of the forward speed, so the system continues to struggle with the TUTT. The low-level vorticity maximum would then move, as it appears to be doing, S of due west and would be over the NE coast of Cuba in about two days. This fits with some of the models like the HWRF, the ECMWF, and the GFDL. Edit: As of 1445Z, the LLV may be attempting to relocate a bit farther NE. The low-level clouds to the S of the LLV appear to have shifted from SW to more of a WSW component, perhaps. If a center relocation closer to the MLV were to occur, and if new convection were to redevelop near the MLV, then the system might gain more time over water and pass just N of Cuba in about two days. It would also be a bit better equipped to withstand the shear. PR radar is back up. Still can't tell from that or the satellite if a new LLC has formed. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 Waiting to see recon. GFS intialized Dorian as a weak system, which may be wrong based on satellite appearance, and quickly weakens it to almost nothing. But I'm not sure GFS initialization is wrong. I will compare low level winds to Hour 6 GFS forecasts, if they match up well, the GFS has performed decently most runs on Dorian. Recon had a short flight, not far from Zombie Dorian now... Link to comment Share on other sites More sharing options...
wxmx Posted July 29, 2013 Share Posted July 29, 2013 Looking at ASCAT and visible imagery, there's still nothing under the mid level turning, the axis of the trough, where the wind shift is, is well removed from the convection, around 67-68W. Link to comment Share on other sites More sharing options...
phil882 Posted July 29, 2013 Author Share Posted July 29, 2013 Looking at ASCAT and visible imagery, there's still nothing under the mid level turning, the axis of the trough, where the wind shift is, is well removed from the convection, around 67-68W. Yep, and this is pretty much in line with both the GFS and ECMWF... Convection should collapse just like yesterday without any sort of llc to force convergence. Link to comment Share on other sites More sharing options...
CoastalWx Posted July 29, 2013 Share Posted July 29, 2013 Yep, and this is pretty much in line with both the GFS and ECMWF... Convection should collapse just like yesterday without any sort of llc to force convergence. And it still looks like crap on the 12z GFS. Not always a good sign when the globals look as bad as they do, but we'll see what the next 24 hrs bring. Link to comment Share on other sites More sharing options...
Ground Scouring Posted July 29, 2013 Share Posted July 29, 2013 And it still looks like crap on the 12z GFS. Not always a good sign when the globals look as bad as they do, but we'll see what the next 24 hrs bring. Is the convection collapsing due to mid-level dry air? The nearby soundings have not shown much of it. Edit: Yes, the lack of LL convergence is the most significant factor. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 29, 2013 Share Posted July 29, 2013 Dewpoints on recon are generally only a couple ºC below air temp. Best winds, close to 30 knots flight level, seemed back towards MLC, so I'm still 3/128th glass optimistic. Shear doesn't look that terrible if it could somehow form a new LLC under the MLC. Shear gets worse in a hurry towards the current low level max vorticity. Edit to add Dry air isn't a problem at recon level, but area soundings, air is pretty dry above 800 mb... EDIT TO ADD Part Deux 30% now on TWOAT, but it was the only game in town... Link to comment Share on other sites More sharing options...
CooL Posted July 29, 2013 Share Posted July 29, 2013 This wave looks pretty sheared. Most of the cloud tops are blowing north http://www.ssd.noaa.gov/goes/east/carb/flash-avn.html Link to comment Share on other sites More sharing options...
Weathergun Posted July 29, 2013 Share Posted July 29, 2013 Based on recon reports so far, the surface trough has opened up.This isn't anywhere close to producing a LLC. It's more disorganizaed then yesterday. Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 29, 2013 Share Posted July 29, 2013 Based on recon reports so far, the surface trough has opened up.This isn't anywhere close to producing a LLC. It's more disorganizaed then yesterday. Exactly. Once the convection of this MCV fades away, I think it's time we move onto August. Recon hasn't found anything outside of strong easterlies It was a nice little warm-up for what could be an interesting Cape Verde season, but just as the NHC stated, the chances of redevelopment are diminishing rather quickly with 91L Link to comment Share on other sites More sharing options...
Sunny and Warm Posted July 30, 2013 Share Posted July 30, 2013 Looks like Dorian needs to be taken out back and shot. Link to comment Share on other sites More sharing options...
DopplerWx Posted July 30, 2013 Share Posted July 30, 2013 ugh, how can this thing not develop a llc. looks gorgeous. Link to comment Share on other sites More sharing options...
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