ATL: IRMA - Post-Tropical - Discussion

[Extratropical94]

URNT15 KWBC 032221
NOAA2 0111A IRMA HDOB 19 20170903
221130 1903N 05034W 6952 03204 0059 +117 +012 081048 048 034 001 00
221200 1902N 05036W 6952 03203 0060 +116 +021 079047 048 032 001 00
221230 1902N 05039W 6952 03204 0059 +118 +020 078047 047 032 001 00
221300 1902N 05041W 6952 03204 0062 +116 +018 076047 047 033 001 00
221330 1901N 05044W 6951 03207 0062 +117 +023 074046 046 034 002 00
221400 1901N 05047W 6951 03207 0063 +116 +018 074046 046 034 003 00
221430 1900N 05049W 6952 03207 0062 +116 +025 075047 047 034 002 00
221500 1900N 05052W 6952 03206 0066 +113 +024 074048 048 033 002 00
221530 1859N 05054W 6952 03207 0065 +114 +024 074046 047 033 001 00
221600 1859N 05057W 6952 03208 0065 +116 +021 074046 046 030 001 00
221630 1859N 05100W 6952 03206 0065 +114 +024 074045 046 030 001 00
221700 1858N 05102W 6951 03209 0072 +110 +031 072045 046 032 002 00
221730 1858N 05105W 6950 03210 0073 +109 +030 071046 047 033 002 03
221800 1856N 05107W 6952 03206 0071 +108 +035 071046 046 033 003 03
221830 1854N 05106W 6952 03207 0069 +110 +033 069047 047 024 002 03
221900 1852N 05105W 6952 03204 0066 +111 +032 068046 046 028 002 00
221930 1851N 05104W 6952 03203 0064 +112 +028 066047 047 031 001 00
222000 1849N 05103W 6952 03203 0064 +112 +024 065048 049 030 001 00
222030 1847N 05102W 6951 03203 0064 +111 +027 064049 050 028 002 00
222100 1845N 05101W 6952 03202 0062 +112 +027 065049 050 030 001 00

[Kingarabian]

[otowntiger]

Maybe a bit north of due west, but it didn't look like WNW to me. In any extent, that was simply a trochoidal wobble.
I think a few Twitter posts got a little too caught up in its significance.

AJC3: how concerned are you for a possible significant impact here in central Florida at this time?

Obviously we need to pay close attention, but it won't be known for several more days how serious the threat will eventually be.
A lot of equally plausible options are still on the table. Still about a week away from any potential impact.

thanks! Just watching the 18z GFS and it's amazing how consistant it and the Euro have been over their last several runs doing a Floyd/Matthew type turn up the coast. I know the closer we get the more likely that scenario starts to become over the others if it continues. Do you think that once we are within 5 days that the forecast confidence will be high Or do you see the synoptic pattern being more complicated than usual,therefore lower confidence?

[Extratropical94]

URNT15 KWBC 032231
NOAA2 0111A IRMA HDOB 20 20170903
222130 1844N 05100W 6952 03200 0058 +113 +030 065051 051 030 001 00
222200 1842N 05059W 6951 03198 0056 +114 +028 066053 053 031 001 00
222230 1840N 05058W 6952 03194 0053 +114 +027 066053 053 031 001 00
222300 1838N 05057W 6952 03195 0054 +112 +023 065054 054 030 002 00
222330 1837N 05056W 6951 03193 0059 +106 +029 062053 054 033 001 00
222400 1835N 05055W 6952 03192 0055 +109 +030 061054 055 032 001 00
222430 1833N 05054W 6956 03185 0050 +109 +046 062054 054 031 002 00
222500 1831N 05053W 6964 03174 0050 +108 +050 061053 054 032 002 00
222530 1830N 05052W 6952 03185 0052 +104 +054 061053 054 035 002 00
222600 1828N 05050W 6952 03183 0055 +099 +062 062055 055 035 001 00
222630 1826N 05049W 6967 03165 0057 +095 +073 063057 058 036 001 00
222700 1824N 05048W 6948 03185 0052 +096 +073 064057 058 036 002 00
222730 1822N 05047W 6954 03175 0049 +097 +075 066057 059 036 001 00
222800 1821N 05046W 6949 03182 0044 +098 +073 070054 055 036 002 00
222830 1819N 05045W 6941 03183 0045 +094 +075 072062 065 035 005 00
222900 1817N 05044W 6956 03167 0048 +095 +064 071063 065 033 005 00
222930 1816N 05043W 6952 03170 0045 +094 +068 067063 063 036 005 00
223000 1814N 05042W 6963 03155 0043 +094 +079 067062 063 034 004 00
223030 1812N 05041W 6952 03167 0038 +094 +088 067061 061 033 002 00
223100 1811N 05040W 6956 03158 0035 +096 +073 066062 063 033 002 00

[Kingarabian]

[Extratropical94]

[caneseddy]

 https://twitter.com/TWCBryan/status/904450404754358272

[Extratropical94]

URNT15 KWBC 032241
NOAA2 0111A IRMA HDOB 21 20170903
223130 1809N 05039W 6962 03149 0037 +093 +068 064062 063 034 002 00
223200 1807N 05038W 6952 03159 0031 +093 +081 063064 065 033 004 00
223230 1806N 05037W 6941 03165 0034 +088 +071 063060 061 034 001 00
223300 1804N 05036W 6952 03156 0033 +089 +078 065058 059 035 002 00
223330 1802N 05035W 6951 03153 0028 +089 +081 064060 061 037 002 00
223400 1800N 05034W 6951 03150 0023 +090 +079 061061 062 036 002 00
223430 1759N 05033W 6952 03143 0015 +093 +078 058062 062 036 001 00
223500 1757N 05032W 6950 03141 0008 +094 +076 058063 063 038 002 00
223530 1755N 05030W 6952 03135 9999 +099 +072 058062 063 039 002 00
223600 1753N 05029W 6957 03122 9993 +100 +071 059064 064 042 002 00
223630 1752N 05028W 6961 03116 9978 +110 +066 054062 063 041 002 00
223700 1750N 05027W 6963 03109 9974 +109 +066 055062 063 044 002 00
223730 1748N 05026W 6957 03111 9963 +110 +078 056064 065 045 002 00
223800 1746N 05025W 6968 03090 9956 +110 +086 055066 068 048 003 00
223830 1744N 05024W 6951 03106 9944 +112 +091 057072 074 051 003 00
223900 1743N 05023W 6957 03083 9929 +113 +101 055078 080 054 003 00
223930 1741N 05022W 6967 03061 9909 +119 +094 053077 077 056 003 00
224000 1739N 05021W 6951 03069 9892 +124 +069 050080 084 062 001 00
224030 1737N 05020W 6939 03059 9873 +122 +084 049089 092 066 002 00
224100 1735N 05018W 6953 03025 9849 +121 +099 049093 093 073 004 00

[MGC]

What alarms me is the slight track adjustment. This from the 5pm discussion: " The updated track is not very different from the previous advisory, except at day 5 where it is slightly west of the previous forecast." Told my son in Norfolk to pay close attention to Irma. Repeated forecast track changes to the west.....where have I seen that before?......MGC

[Kingarabian]

[Kingarabian]

Next HDOB will be the center.

[Nimbus]

GFS has been consistent in the short term as well, should put almost all the islands on the weaker side of the storm. As long as those wind fields don't expand and the track doesn't go any further south.
I will start getting concerned tomorrow night if Irma doesn't level off north of 16.6N though.

[WeatherGuesser]

Repeated forecast track changes to the west.....where have I seen that before?...

Most past storms? They nearly all change at every update.

[Kingarabian]

959mb this pass. Winds @ 99kts. Supports 100kt winds.

Edit nvm the SFMR's are lower. Maybe 90-95kts.

[Extratropical94]

959 again

URNT15 KWBC 032251
NOAA2 0111A IRMA HDOB 22 20170903
224130 1734N 05017W 6954 02996 9799 +137 +109 048098 099 076 006 00
224200 1732N 05016W 6957 02962 9756 +144 +115 044094 098 081 007 00
224230 1730N 05015W 6957 02929 9718 +146 +123 039087 089 082 005 00
224300 1728N 05013W 6956 02897 9667 +160 +116 036079 081 076 004 00
224330 1727N 05012W 6963 02852 9618 +176 +103 033070 075 070 001 00
224400 1726N 05010W 6967 02821 9590 +174 +112 031049 055 056 002 00
224430 1725N 05008W 6961 02819 9587 +164 +118 053028 033 036 002 00
224500 1723N 05007W 6955 02824 9588 +160 +121 076018 023 031 003 03
224530 1721N 05006W 6948 02834 9588 +162 +120 137005 007 020 001 03
224600 1719N 05005W 6958 02828 9597 +161 +116 240015 019 026 002 03
224630 1717N 05004W 6956 02847 9623 +149 +128 244027 032 037 003 00
224700 1716N 05003W 6971 02852 9656 +141 +133 250043 050 051 004 00
224730 1714N 05002W 6942 02913 9692 +136 //// 242064 071 078 014 01
224800 1712N 05001W 6942 02952 9744 +125 //// 238077 085 083 020 01
224830 1710N 05000W 6910 03028 9801 +109 //// 230085 087 079 029 01
224900 1709N 04959W 6961 02997 9846 +102 //// 232080 081 072 036 05
224930 1707N 04958W 6952 03031 9865 +107 //// 230075 077 066 016 01
225000 1705N 04957W 6966 03033 9893 +102 //// 231071 072 063 014 01
225030 1704N 04956W 6954 03061 9921 +093 //// 231065 067 058 010 01
225100 1702N 04955W 6957 03072 9935 +096 //// 228059 060 053 007 01

[GCANE]

Radar from Kermit

[CrazyC83]

This seems to be most similar to Floyd and Frances in terms of how the trough could affect the track. A tough forecast down the road...with an escape hatch still open but a wide range of possibilities.

What were the 500mb heights when those two storms were in the Bahamas?

[Chris_in_Tampa]

Center at 6:36:40pm EDT:



Credit: NOAA-AOC

[Kingarabian]

[CrazyC83]

Seems to be due west right now based on Recon fixes - 17°23' before, 17°25' now.