ATL: IRMA - Post-Tropical - Discussion

[Sciencerocks]

000
URNT15 KNHC 100747
AF302 2911A IRMA HDOB 48 20170910
073730 2333N 08044W 6962 02927 9745 +130 +113 208077 078 060 001 00
073800 2332N 08042W 6965 02931 9755 +127 +113 207077 078 060 004 00
073830 2331N 08041W 6962 02940 9775 +113 //// 205073 076 061 007 01
073900 2331N 08039W 6966 02937 9786 +107 //// 199070 071 059 011 05
073930 2330N 08038W 6962 02946 9790 +108 //// 198071 072 060 010 01
074000 2329N 08036W 6967 02946 9785 +117 +111 198071 072 061 005 00
074030 2328N 08035W 6965 02953 9778 +127 +108 199072 072 061 005 00
074100 2327N 08033W 6962 02960 9778 +132 +100 200072 072 061 003 00
074130 2327N 08032W 6967 02958 9784 +131 +106 202072 072 061 003 00
074200 2326N 08030W 6963 02969 9801 +119 +108 202072 072 060 003 00
074230 2325N 08029W 6963 02972 9823 +106 //// 203074 075 058 006 01
074300 2324N 08027W 6961 02981 9828 +105 //// 204075 076 057 006 01
074330 2324N 08026W 6965 02972 9823 +108 +107 203075 075 058 005 00
074400 2323N 08025W 6963 02976 9833 +102 +101 202076 076 056 007 00
074430 2322N 08023W 6966 02977 9851 +091 //// 203077 078 053 010 05
074500 2321N 08022W 6962 02985 9851 +094 //// 203076 076 049 014 01
074530 2320N 08020W 6966 02983 9852 +095 //// 203075 076 050 012 05
074600 2320N 08019W 6965 02989 9855 +098 //// 204075 075 050 012 05
074630 2319N 08017W 6963 02997 9861 +097 //// 205074 075 050 007 05
074700 2318N 08016W 6965 02998 9854 +105 +104 208075 076 049 007 00
$$
;

[northjaxpro]

I am wondering what is causing the eyewall to be open at the moment? Is dry air trying to intrude into the core?

[Aric Dunn]

You mean the 00Z GFS. The 06Z cycle won't be running for another couple hours.

Thoughts on the shear AJ?

Looks legit based upon the position of the short wave trough. The issue is twofold. 1. The shear is divergent, which isn't nearly as detrimental and tends to enhance poleward outflow. 2. The well established upper level anticyclone should be able to fight off the shear initially.

Still, the southern eyewall has remained open for several hours now. We'll see what the next few hours brings...

yeah soo.. the outer rain band far SW of the center gives it away. along with the moat. there is some undercutting shear.. the convection in the eyewall builds and the outflow from it tries to expand south westward ( part of it towers up ) but at some level there is some SW shear at the same time the heavy band to the SW being slightly enhanced by the shear also start expanding in the mid to upper levels .. the eyewall convection expanding and the convective band ( thats being enhanced ) expand and eventually converge and sink creating the moat and the lack of a southern eyewall. its happens nearly everytime a northern moving system interacts with a trough and SW flow...

unless something changes.. the southern eyewall will likely stay open ..

[Steve]

928. Dropping still.

[Sciencerocks]

000
URNT15 KNHC 100807
AF302 2911A IRMA HDOB 50 20170910
075730 2356N 08006W 6961 02992 9848 +100 //// 181083 085 061 008 01
075800 2359N 08006W 6967 02982 9839 +107 +102 181083 084 063 007 00
075830 2401N 08006W 6966 02985 9841 +105 +103 180083 083 062 008 00
075900 2404N 08006W 6964 02987 9845 +102 //// 179084 085 065 010 01
075930 2406N 08005W 6965 02986 9850 +099 //// 177084 085 063 011 01
080000 2408N 08005W 6964 02987 9845 +103 //// 178084 084 062 007 01
080030 2411N 08005W 6966 02985 9836 +110 +105 177084 084 063 007 00
080100 2413N 08005W 6963 02991 9839 +109 +104 175085 087 064 007 00
080130 2416N 08005W 6967 02988 9850 +102 //// 174083 085 063 007 01
080200 2418N 08004W 6964 02994 9849 +105 //// 173084 086 063 007 01
080230 2421N 08004W 6967 02992 9844 +110 +107 172084 086 062 007 00
080300 2423N 08004W 6970 02990 9859 +099 //// 171085 086 058 011 01
080330 2425N 08004W 6967 02994 9866 +095 //// 170083 084 059 013 01
080400 2428N 08003W 6953 03010 9866 +095 //// 165084 085 061 012 05
080430 2430N 08003W 6967 02997 //// +095 //// 160084 085 061 012 05
080500 2433N 08003W 6971 02995 9872 +095 //// 160080 082 059 016 05
080530 2435N 08003W 6963 03004 9876 +094 //// 159080 085 061 012 01
080600 2437N 08003W 6968 03003 9887 +088 //// 151084 086 061 010 01
080630 2439N 08002W 6962 03010 9888 +087 //// 148081 081 061 010 01
080700 2442N 08002W 6969 03004 9895 +085 //// 146084 084 063 012 01
$$

[Hurricane Andrew]

Recon says eyewall is closed. By the way, the NWS guys are locked down and ready in Key West. They are there to do their jobs, and I am so impressed with them. Truly underappreciated heroes. I will keep checking in with them, if I can, make sure they are all alright.

[Aric Dunn]

its a strong hurricane .. but its very tilted .. im surprised after watching this the last couple hours it deepened as much as it has.

[AJC3]

Recon says eyewall is closed.

Indeed. However, given its radar presentation on both the Key West and Casablanca radars, suffice it to say that southern eyewall is weak, and may not stay closed for very much longer. It would be nice to get a radar snap from the plane right about now...

[Hurricane Andrew]

Recon says eyewall is closed.

Indeed. However, given its radar presentation on both the Key West and Casablanca radars, suffice it to say that southern eyewall is weak, and may not stay closed for very much longer. It would be nice to get a radar snap from the plane right about now...

Couldn't that be the intensity of the N eyewall blocking the beam, like we saw with Harvey?

[northjaxpro]

Yeah, I commend those guys at the Key West WFO. Doing their job well. A night/morning they won't forget for sure with a powerful Cat 4 tropical cyclone bearing down on them!!

[tallywx]

its a strong hurricane .. but its very tilted .. im surprised after watching this the last couple hours it deepened as much as it has.

Hurricane Hugo had the moat too as it was intensifying as a Cat 4 to land:

[Sciencerocks]

000
URNT15 KNHC 100817
AF302 2911A IRMA HDOB 51 20170910
080730 2444N 08002W 6963 03014 9896 +085 //// 147083 084 061 012 01
080800 2446N 08002W 6969 03013 9906 +082 //// 141081 082 056 014 05
080830 2448N 08002W 6957 03026 9905 +084 //// 143084 085 054 018 01
080900 2451N 08001W 6970 03013 9908 +084 //// 141086 087 055 015 05
080930 2453N 08001W 6963 03023 9909 +084 //// 141079 083 056 011 01
081000 2455N 08001W 6962 03027 9903 +090 //// 143078 078 056 011 05
081030 2457N 08001W 6966 03025 9905 +090 //// 144077 078 057 011 01
081100 2459N 08001W 6961 03036 9899 +100 +087 145074 076 058 006 00
081130 2501N 08000W 6969 03030 9895 +106 +085 143076 078 058 004 00
081200 2504N 08000W 6967 03035 9899 +106 +085 141073 077 057 004 00
081230 2506N 08000W 6965 03041 9902 +107 +083 140071 072 056 005 00
081300 2508N 08000W 6961 03047 9912 +100 +090 138070 071 057 005 03
081330 2510N 08000W 6964 03046 9917 +097 +093 137070 071 057 005 00
081400 2512N 07959W 6965 03048 9926 +093 +088 140069 072 054 007 00
081430 2514N 07959W 6964 03053 9941 +085 //// 134073 074 053 010 01
081500 2516N 07959W 6961 03059 9946 +084 //// 133070 073 054 009 01
081530 2518N 07959W 6966 03056 9947 +085 //// 137067 067 051 010 05
081600 2520N 07959W 6955 03069 9947 +085 //// 137067 067 /// /// 05
081630 2521N 08001W 6966 03056 9942 +088 //// 136063 067 /// /// 05
081700 2520N 08002W 6973 03047 9941 +088 //// 136059 059 051 011 05
$$
;

[Aric Dunn]

its a strong hurricane .. but its very tilted .. im surprised after watching this the last couple hours it deepened as much as it has.

Hurricane Hugo had the moat too as it was intensifying as a Cat 4 to land:

Katrina also had one as it was weakening towards land... has to do with convergent flow from the convection in different areas sinking .. happens a lot ..

[NDG]

Comparing at the 0z GFS & Euro, the GFS is doing horrible, is verifying too fast and wanting to deepen Irma too fast as well. For 5 AM this morning it was forecasting it to be at 913 mb, clearly based on the latest pass a few minutes ago it will not reach it by then.
The GFS has it making landfall just east of Key West at 7 AM this morning, with a pressure of 917mb, not going to happen.
Then it has making landfall near Marco Island at 2 PM this afternoon with a pressure of 908 mb.
On the other hand the Euro has it making landfall on Key West almost a couple of hours later, right before 9 AM but with pressures gradually falling, keeping a NNW track instead of almost a due N track by the GFS, making a partial landfall further north in Sarasota County by 11 PM tonight, giving it time to keep intensifying as it shows a pressure drop of 18 mb from now until is west of Cape Coral, after that time it shows pressure start coming up which makes sense as it starts feeling more windshear.
After making a partial landfall in Sarasota County it has it going back offshore tracking Parallel to the coast all the way to Apalachicola Bay, making landfall in the Big Bend area, at Taylor County at 1 PM tomorrow afternoon, this would be a very bad run if it verifies for the whole west coast of FL

[Sciencerocks]

000
URNT15 KNHC 100827
AF302 2911A IRMA HDOB 52 20170910
081730 2518N 08003W 6963 03056 9940 +086 //// 133066 071 053 010 01
081800 2517N 08005W 6966 03051 9936 +088 //// 131071 073 055 009 05
081830 2516N 08006W 6960 03054 9924 +096 +082 131066 069 055 008 00
081900 2515N 08007W 6965 03045 9924 +091 +090 131066 066 056 006 00
081930 2514N 08009W 6964 03043 9915 +097 +092 130068 069 058 006 00
082000 2512N 08010W 6969 03036 9909 +100 +086 132069 069 057 006 00
082030 2511N 08011W 6967 03036 9912 +096 +087 133070 071 057 006 00
082100 2510N 08013W 6961 03040 9919 +086 //// 134070 071 058 009 01
082130 2509N 08014W 6961 03034 9909 +091 +088 135072 072 060 008 00
082200 2508N 08015W 6970 03020 9899 +097 +089 133072 074 061 007 00
082230 2507N 08017W 6959 03029 9908 +084 //// 132074 075 068 008 01
082300 2505N 08018W 6966 03020 9908 +084 //// 133077 079 074 015 01
082330 2504N 08019W 6961 03021 9901 +085 //// 128081 083 075 026 05
082400 2503N 08021W 6960 03021 9898 +087 //// 128080 081 076 015 01
082430 2502N 08022W 6955 03025 9899 +086 //// 126080 083 074 015 05
082500 2501N 08023W 6969 03010 9892 +091 //// 137081 083 074 011 01
082530 2500N 08024W 6955 03025 9886 +092 //// 136081 082 077 015 01
082600 2459N 08026W 6966 03009 9883 +094 //// 146075 080 085 020 01
082630 2457N 08027W 6960 03014 //// +095 //// 145081 082 078 020 01
082700 2456N 08028W 6967 03004 9875 +097 //// 149078 082 081 019 01
$$
;

[WeatherGuesser]

Recon says eyewall is closed.

Indeed. However, given its radar presentation on both the Key West and Casablanca radars, suffice it to say that southern eyewall is weak, and may not stay closed for very much longer. It would be nice to get a radar snap from the plane right about now...

I don't know where or what the Casablanca radar is, but I have to wonder if the image of the eyewall isn't an illusion caused by the Key West beam being blocked by the heavy northern convection.

[Aric Dunn]

Recon says eyewall is closed.

Indeed. However, given its radar presentation on both the Key West and Casablanca radars, suffice it to say that southern eyewall is weak, and may not stay closed for very much longer. It would be nice to get a radar snap from the plane right about now...

I don't know where or what the Casablanca radar is, but I have to wonder if the image of the eyewall isn't an illusion caused by the Key West beam being blocked by the heavy northern convection.

http://www.met.inf.cu/asp/genesis.asp?T ... AXw01a.gif


nope .. its sinking air caused by some differential flow from the shear and various convective bands..

[Clint_TX]

Recon says eyewall is closed.

Indeed. However, given its radar presentation on both the Key West and Casablanca radars, suffice it to say that southern eyewall is weak, and may not stay closed for very much longer. It would be nice to get a radar snap from the plane right about now...

. Good to read you on here Tony, long time sir!

[bamajammer4eva]

I'm starting to wonder if hurricane warnings may have to be issued for SE AL at 5 AM or 11 AM. This has gotten stronger than anticipated with cat 4 vs predicted cat 3 and its following the Euro as far as track. 11PM brought hurricane warnings to the GA/AL border including Seminole and Early county GA

[Aric Dunn]

by the way.. doppler velocities now showing 139 kts in the eyewall. at about 2500 feet..