U_Thant Posted October 27, 2011 Share Posted October 27, 2011 Yep, it's a non classic display of southerly shear, convection is even a little lopsided to the south. The CI canopy of the CDO has the look of shear that is undercutting the outflow - really sharp edge to the cold top canopy on the south side. Link to comment Share on other sites More sharing options...
hm8 Posted October 27, 2011 Share Posted October 27, 2011 Link to comment Share on other sites More sharing options...
CUmet Posted October 27, 2011 Share Posted October 27, 2011 This is pretty much the same thing that happend with Jova. It was experiencing southeasterly shear but the coldest cloud tops were located in the SE quadrant. CUmet has posted extensively about this, but it has to do with dry air being advected into the core from the south. From what I understand when you still have a decently organized eyewall, thunderstorms rotate around the inner core very rapidly. Thus, even though the strongest convection is in the north quadrant, the fast rotational speed within the eyewall causes the cold cloud tops aloft from those thunderstorms in the N eyewall to rotate and be oriented 180 degrees to where they originated. Hense the lopsided appearance of the deep convection in the same direction the shear originates. That's right, the IR/WV cloud tops are always going to be cyclonically downstream of downshear or downshear-left. The cloud tops will be even more out of phase with the shear in small storms like this one because it has less distance to travel per azimuthal change. To clarify further, it's not particularly easy to diagnose where the dry air is coming from in sheared cases. There have been attempts to incorporate both total precipitable water data and the shear direction together in updates to SHIPS, and so far to my knowledge there's never been any combination that's consistently added to predictive skill. The TPW + shear magnitude does though. Link to comment Share on other sites More sharing options...
hm8 Posted October 27, 2011 Share Posted October 27, 2011 Last minute strengthening again for Josh? Link to comment Share on other sites More sharing options...
wxmx Posted October 27, 2011 Author Share Posted October 27, 2011 Damn, this Rina girl sure is fickle. After being harbinger of good news, now I turn to be an omen of disgrace... Rina is looking worse after the nose dive and posterior great rebound. Radar shows the eyewall has not just opened, but it's probably close to being half an eyewall now, my guess is the next MW will not be that good. Of course she can pull it off again before landfall, I wouldn't be surprised, her small size and not that good upper level flow but very good SSTs are very difficult to forecast. My guess is steady until landfall...but I can be off by 10-15 kts either way. Link to comment Share on other sites More sharing options...
U_Thant Posted October 27, 2011 Share Posted October 27, 2011 Damn, this Rina girl sure is fickle. After being harbinger of good news, now I turn to be an omen of disgrace... Rina is looking worse after the nose dive and posterior great rebound. Link to comment Share on other sites More sharing options...
David Reimer Posted October 27, 2011 Share Posted October 27, 2011 Based on the first pass by the Hurricane Hunters, it looks like the minimum central pressure is now around 988-990 MB with max flight level winds around 66 knots. Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 27, 2011 Share Posted October 27, 2011 Based on the first pass by the Hurricane Hunters, it looks like the minimum central pressure is now around 988-990 MB with max flight level winds around 66 knots. URNT12 KNHC 270615 VORTEX DATA MESSAGE AL182011 A. 27/05:56:30Z B. 18 deg 40 min N 086 deg 44 min W C. 700 mb 3041 m D. 53 kt E. 079 deg 15 nm F. 133 deg 66 kt G. 072 deg 19 nm H. EXTRAP 993 mb I. 8 C / 3049 m J. 17 C / 3041 m K. 4 C / NA L. NA M. NA N. 1345 / 7 O. 0.02 / 5 nm P. AF306 1118A RINA OB 05 MAX FL WIND 66 KT E QUAD 05:50:30Z SLP EXTRAP FROM 700 MB NO EYE SONDE RELEASED SFMR INDICATED SFC WINDS OVER 40 KTS AT FL FIX POSN GOOD RAIN SHIELD ON RADAR TO THE NORTH BUT NO CLEAR EYEWALL EVIDENT Link to comment Share on other sites More sharing options...
David Reimer Posted October 27, 2011 Share Posted October 27, 2011 URNT12 KNHC 270615 VORTEX DATA MESSAGE AL182011 A. 27/05:56:30Z B. 18 deg 40 min N 086 deg 44 min W C. 700 mb 3041 m D. 53 kt E. 079 deg 15 nm F. 133 deg 66 kt G. 072 deg 19 nm H. EXTRAP 993 mb I. 8 C / 3049 m J. 17 C / 3041 m K. 4 C / NA L. NA M. NA N. 1345 / 7 O. 0.02 / 5 nm P. AF306 1118A RINA OB 05 MAX FL WIND 66 KT E QUAD 05:50:30Z SLP EXTRAP FROM 700 MB NO EYE SONDE RELEASED SFMR INDICATED SFC WINDS OVER 40 KTS AT FL FIX POSN GOOD RAIN SHIELD ON RADAR TO THE NORTH BUT NO CLEAR EYEWALL EVIDENT LOL The rapid degeneration of this system is awesome from a end of the season aspect. Alright, back to my Texas Snow. Link to comment Share on other sites More sharing options...
Inudaw Posted October 27, 2011 Share Posted October 27, 2011 Ouch... Too bad for josh? Link to comment Share on other sites More sharing options...
HurricaneJosh Posted October 27, 2011 Share Posted October 27, 2011 I'm not surprised by the recon readings, looking at the IR-- it really deteriorated over the last couple of hours. Very weird system-- just up and down. P.S. The 1 am advisory (which just came out) seems not to reflect the current situation-- I guess they'll wait until 4 am CDT to make any big changes. Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 Did the transponder stop working on NOAA42? Link to comment Share on other sites More sharing options...
Srain Posted October 27, 2011 Share Posted October 27, 2011 Center is becoming exposed. There are some questionable readings from RECON. Last set just came in, Adam: URNT15 KWBC 271334 NOAA2 1218A RINA HDOB 14 20111027 132430 1912N 08653W 6991 03091 9910 +176 +088 059024 033 056 036 00 132500 1910N 08654W 6994 03081 9924 +154 +119 067027 033 062 023 00 132530 1908N 08654W 6957 03116 9918 +151 +121 036018 022 056 019 00 132600 1906N 08654W 6979 03087 9905 +162 +106 350023 025 /// /// 03 132630 1904N 08653W 6976 03093 9905 +163 +106 330019 023 /// /// 03 132700 1904N 08651W 6972 03093 9915 +153 +087 187007 011 027 003 00 132730 1904N 08648W 6961 03109 9923 +149 +080 201015 017 038 005 00 132800 1904N 08646W 6959 03117 9937 +140 +097 189023 025 045 003 00 132830 1904N 08644W 6949 03134 9942 +139 +097 185029 030 050 005 00 132900 1904N 08642W 6973 03110 9955 +128 +119 184044 050 051 004 00 132930 1904N 08639W 6968 03120 9969 +123 //// 186044 047 048 003 01 133000 1904N 08637W 6971 03124 9982 +118 //// 183045 049 047 001 01 133030 1904N 08635W 6967 03134 0006 +105 //// 176050 053 045 003 01 133100 1904N 08633W 6985 03116 0012 +106 +106 175049 050 045 004 00 133130 1904N 08631W 6974 03135 0012 +110 +103 176051 052 045 009 00 133200 1904N 08629W 6972 03137 0013 +109 +114 182052 054 045 012 00 133230 1904N 08626W 6942 03176 0019 +103 //// 178047 049 041 009 01 133300 1904N 08624W 6941 03180 0024 +102 //// 178046 048 039 005 01 133330 1904N 08622W 6978 03137 0032 +101 //// 177043 044 037 004 01 133400 1904N 08620W 6944 03182 0040 +094 //// 174044 045 035 003 01 Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 You can follow along with the plane obs using twitter as well: @HRD_AOML_NOAA Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 Max flight level so far is 54kts... but they haven't done a center fix yet. Link to comment Share on other sites More sharing options...
Srain Posted October 27, 2011 Share Posted October 27, 2011 000 URNT12 KWBC 271415 VORTEX DATA MESSAGE AL182011 A. 27/1327Z B. 19 DEG 4 MIN N 86 DEG 51 MIN W C. 700 MB 3060 M D. 62 KT E. 341 DEG 6 NM F. 109 DEG 38 KT G. 359 DEG 15 NM H. EXTRAP 989 MB I. 16 C/3055 M J. 17 C/3043 M K. 10 C/NA L. POORLY DEFINED M. NA N. 12345/7 O. 1/1 NM P. NOAA2 1218A RINA OB 09 MAX OUTBOUND AND FL WIND 55KT E QUAD 1330Z EXTRAP 989MB FROM 10K FT ELECTRIFIED CELL N OF CNTR Link to comment Share on other sites More sharing options...
wxmx Posted October 27, 2011 Author Share Posted October 27, 2011 Center is becoming exposed. There are some questionable readings from RECON. Last set just came in, Adam: It was exposed earlier this morning, it's now becoming covered by deep convection. Link to comment Share on other sites More sharing options...
wxmx Posted October 27, 2011 Author Share Posted October 27, 2011 They will probably keep it a hurricane this time. Link to comment Share on other sites More sharing options...
Srain Posted October 27, 2011 Share Posted October 27, 2011 It was exposed earlier this morning, it's now becoming covered by deep convection. Yeah, I see shear has abated a bit. One last gasp... Link to comment Share on other sites More sharing options...
CoastalWx Posted October 27, 2011 Share Posted October 27, 2011 I haven't paid close attention to this, and maybe Adam can back me up or clarify, but it seemed once again that the globals and esp the euro hinted at the shear and weakening with Rina. They aren't tropical models, but they love to drop clues sometimes. Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 I haven't paid close attention to this, and maybe Adam can back me up or clarify, but it seemed once again that the globals and esp the euro hinted at the shear and weakening with Rina. They aren't tropical models, but they love to drop clues sometimes. Yep, Euro and UKMet have been the big winners over the last 48 hours (and the GFS EnKF on and off). Link to comment Share on other sites More sharing options...
HurricaneJosh Posted October 27, 2011 Share Posted October 27, 2011 They will probably keep it a hurricane this time. Nope-- downgraded! Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 Nope-- downgraded! Given the flight level winds so far, 60 kts might be generous Link to comment Share on other sites More sharing options...
Srain Posted October 27, 2011 Share Posted October 27, 2011 There are some questionable readings from RECON. Given the flight level winds so far, 60 kts might be generous Yeah, I agree Link to comment Share on other sites More sharing options...
HurricaneJosh Posted October 27, 2011 Share Posted October 27, 2011 Given the flight level winds so far, 60 kts might be generous Doesn't the VDM indicate a surface wind of 62 kt? Either way, it makes sense, I guess-- although the IR presentation has improved the last couple of hours. Like Jorge said, the center is covered again. Link to comment Share on other sites More sharing options...
am19psu Posted October 27, 2011 Share Posted October 27, 2011 Doesn't the VDM indicate a surface wind of 62 kt? Yeah, but I always question those obs when the max flight level wind is only 55 kts. I guess they are flying relatively high at 700mb (3100m) though. Link to comment Share on other sites More sharing options...
Srain Posted October 27, 2011 Share Posted October 27, 2011 000 URNT12 KWBC 271458 VORTEX DATA MESSAGE AL182011 A. 27/1440Z B. 19 DEG 10 MIN N 86 DEG 51 MIN W C. 700 MB 3066 M D. 48 KT E. 144 DEG 8 NM F. 233 DEG 42 KT G. 140 DEG 5 NM H. EXTRAP 991 MB I. 11 C/3060 M J. 18 C/3058 M K. 8 C/NA L. POORLY DEFINED M. NA N. 12345/7 O. 1/1 NM P. NOAA2 1218A RINA OB 16 MAX FL WIND 55KT E QUAD 1330Z MAX OUTBOUND FL WIND 51KT NE QUAD 1448Z SFC CNTR SW OF FL CNTR 5NM Link to comment Share on other sites More sharing options...
wxmx Posted October 27, 2011 Author Share Posted October 27, 2011 Small size, 991mb and strong convection, 60kts sounds about right, in spite of the low FL winds at 700mb. I'm very satisfied with my forecasted track since invest days, but with intensity naso much. Link to comment Share on other sites More sharing options...
Sky-Chaser Posted October 27, 2011 Share Posted October 27, 2011 Good day all, Small size, 991mb and strong convection, 60kts sounds about right, in spite of the low FL winds at 700mb. I'm very satisfied with my forecasted track since invest days, but with intensity naso much. The INTENSITY forecasts are always the most challenging and error-prone. Look at the NHC intensity expected 48 hours ago on 10/25 (showing a 120+ MPH storm hitting Playa del Carmen at about 1-2 PM 10/27). Look at what is actually happening on 10/27 around lunch. The NHC TRACK is very close, verifying quite accurately to what was expected 2-3 days ago. But look how "off" the intensity is. Wow! Link to comment Share on other sites More sharing options...
HurricaneJosh Posted October 27, 2011 Share Posted October 27, 2011 Good day all, The INTENSITY forecasts are always the most challenging and error-prone. Look at the NHC intensity expected 48 hours ago on 10/25 (showing a 120+ MPH storm hitting Playa del Carmen at about 1-2 PM 10/27). Look at what is actually happening on 10/27 around lunch. The NHC TRACK is very close, verifying quite accurately to what was expected 2-3 days ago. But look how "off" the intensity is. Wow! Hey, Chris! How's it going? I was thinking the same thing myself today-- that the skill difference between track forecasting and intensity forecasting is just growing bigger and bigger. The track forecasts continue to impress, and they seem to get more accurate year after year. But intensity forecasting remains a mystery. Link to comment Share on other sites More sharing options...
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