ATL: IRMA - Post-Tropical - Discussion

[supercane4867]

Irma has been encountering near 10kts of SW to southerly shear since last night as shown in the CIMSS shear map, which currently keeps any strengthening in check. The significant deepening in the Bahamas predicted by global models is mainly due to strong poleward outflow channel opening up once she feels the trough to the north

Thank you! Is that shear supposed to decrease as well?

Hurricanes with an outflow pattern that strong tends to fight off wind shear very well. Matthew last year was under 15-20kts of shear all the time while rapid intensifying. So shear probably won't be much of an issue once it reach the Bahamas.

[ScottNAtlanta]

Irma has been encountering near 10kts of SW to southerly shear since last night as shown in the CIMSS shear map, which currently keeps any strengthening in check. The significant deepening in the Bahamas predicted by global models is mainly due to strong poleward outflow channel opening up once she feels the trough to the north

I would be taking those CIMSS shear maps as a grain of salt, it was showing 15 knots of shear over Harvey right when it was intensifying into a Major Hurricane.

They tend to be about 50 miles off. Remember that weather is fluid. Shear maps not so much

[Callista]

I want to add, too, that with so many lives at stake, I cannot for the life of me, figure out what one gains by telling so many reading here that it's OK to sound the all clear at this point.

You could, literally, be dooming thousands to a very bad fate.

What does one hope to gain in doing this? Is it just the sense of "being right" about something? IDK

That's exactly what it is. Go COMPLETELY against the grain "on a hunch" just so that JUST IN CASE they somehow are right, they get a huge pat on the back. Either that or they have Pollyanna syndrome.

I can't blame them that much. I would absolutely love it if this one somehow went back out to sea and didn't make landfall. Aren't we all holding out just a tiny bit of hope for that?

[lando]

"Four of the strongest buildings on the Caribbean island of St. Martin have been destroyed by Hurricane Irma, French Interior Minister Gérard Collomb said at a news conference Wednesday"

[Hurricane Andrew]

Irma has been encountering near 10kts of SW to southerly shear since last night as shown in the CIMSS shear map, which currently keeps any strengthening in check. The significant deepening in the Bahamas predicted by global models is mainly due to strong poleward outflow channel opening up once she feels the trough to the north

Thank you! Is that shear supposed to decrease as well?

Hurricanes with an outflow pattern that strong tends to fight off wind shear very well. Matthew last year was under 15-20kts of shear all the time while rapid intensifying. So shear probably won't be much of an issue once it reach the Bahamas.

Wonderful. I am scared for you guys in FL. Please get out if you can, please.

[NDG]

Latest fix by the recon is 18.19N & 63.99W
Still a Cat 5

VORTEX DATA MESSAGE AL112017
A. 06/14:39:50Z
B. 18 deg 11 min N
063 deg 59 min W
C. 700 mb 2405 m
D. 147 kt
E. 161 deg 11 nm
F. 271 deg 140 kt
G. 169 deg 12 nm
H. 923 mb
I. 10 C / 3053 m
J. 21 C / 3028 m
K. 10 C / NA
L. CLOSED
M. C22
N. 12345 / 7
O. 0.02 / 1 nm
P. AF305 1311A IRMA OB 03
MAX OUTBOUND AND MAX FL WIND 164 KT 034 / 14 NM 14:46:00Z
CNTR DROPSONDE SFC WIND 110 / 7 KT
MAX FL TEMP 21 C 015 / 6 NM FROM FL CNTR
;

[supercane4867]

Irma has been encountering near 10kts of SW to southerly shear since last night as shown in the CIMSS shear map, which currently keeps any strengthening in check. The significant deepening in the Bahamas predicted by global models is mainly due to strong poleward outflow channel opening up once she feels the trough to the north

I would be taking those CIMSS shear maps as a grain of salt, it was showing 15 knots of shear over Harvey right when it was intensifying into a Major Hurricane.

They tend to be about 50 miles off. Remember that weather is fluid. Shear maps not so much

In Irma's case the shear is also pretty evident on satellite imagery. I'm just using it as a reference.

[artist]

This twitter account has a video of some of the damage coming out of St Maarten

https://www.facebook.com/I92SXM/posts/10155790746579783
For some reason I can't post the video here
Here is a separate short one of just one home


Link: https://youtu.be/tUlErkUoyqY

[Extratropical94]

URNT15 KNHC 061536
AF305 1311A IRMA HDOB 19 20170906
152730 1929N 06317W 6965 03138 0026 +095 +090 121065 066 053 000 03
152800 1929N 06317W 6965 03138 //// +092 //// 121068 069 054 001 01
152830 1929N 06321W 6967 03132 0021 +095 +086 118065 068 056 001 00
152900 1929N 06324W 6970 03129 0020 +097 +080 118065 065 056 001 00
152930 1929N 06324W 6970 03129 0016 +099 +076 116065 066 055 001 03
153000 1929N 06328W 6967 03130 0016 +099 +080 115065 066 054 001 00
153030 1930N 06331W 6963 03136 0015 +099 +080 113064 064 055 000 03
153100 1931N 06333W 6968 03127 0018 +094 +080 113064 065 054 000 00
153130 1932N 06335W 6966 03131 //// +091 //// 107068 069 056 000 01
153200 1932N 06338W 6965 03129 0008 +098 +092 108067 068 057 000 01
153230 1933N 06340W 6969 03127 0011 +101 +084 108066 067 056 001 00
153300 1934N 06342W 6965 03130 0013 +099 +083 108065 066 055 000 03
153330 1934N 06345W 6965 03131 0015 +095 +090 106067 068 057 000 00
153400 1934N 06347W 6970 03121 0010 +098 +086 103069 070 058 000 00
153430 1934N 06350W 6969 03119 0004 +100 +082 104068 069 058 002 00
153500 1934N 06352W 6967 03120 0000 +101 +077 101067 068 057 002 00
153530 1934N 06355W 6963 03121 0000 +100 +077 101067 068 056 002 00
153600 1934N 06357W 6970 03114 0002 +100 +070 100067 068 055 001 00
153630 1934N 06400W 6967 03115 9997 +101 +084 098067 068 055 000 00
153700 1934N 06402W 6970 03113 9992 +104 +091 096069 070 056 001 00

[ScottNAtlanta]

I want to add, too, that with so many lives at stake, I cannot for the life of me, figure out what one gains by telling so many reading here that it's OK to sound the all clear at this point.

You could, literally, be dooming thousands to a very bad fate.

What does one hope to gain in doing this? Is it just the sense of "being right" about something? IDK

That's exactly what it is. Go COMPLETELY against the grain "on a hunch" just so that JUST IN CASE they somehow are right, they get a huge pat on the back. Either that or they have Pollyanna syndrome.

I can't blame them that much. I would absolutely love it if this one somehow went back out to sea and didn't make landfall. Aren't we all holding out just a tiny bit of hope for that?

This is a situation where following "hope" can kill you, but the science will keep you safe if you take note of what it saays

[O Town]

Could argue a little S of the forecast track, may wobble back...

Seriously?!!! Looks like it's straight down the middle to me. I guess if your counting hairs then maybe 1 hair south. Wouldn't even call it a wobble south, just 1 hair....

[meriland29]

Latest fix by the recon is 18.19N & 63.99W
Still a Cat 5

VORTEX DATA MESSAGE AL112017
A. 06/14:39:50Z
B. 18 deg 11 min N
063 deg 59 min W
C. 700 mb 2405 m
D. 147 kt
E. 161 deg 11 nm
F. 271 deg 140 kt
G. 169 deg 12 nm
H. 923 mb
I. 10 C / 3053 m
J. 21 C / 3028 m
K. 10 C / NA
L. CLOSED
M. C22
N. 12345 / 7
O. 0.02 / 1 nm
P. AF305 1311A IRMA OB 03
MAX OUTBOUND AND MAX FL WIND 164 KT 034 / 14 NM 14:46:00Z
CNTR DROPSONDE SFC WIND 110 / 7 KT
MAX FL TEMP 21 C 015 / 6 NM FROM FL CNTR
;

164kts is the highest I have seen yet. Highest I had seen was 163

[rickybobby]

Thank you! Is that shear supposed to decrease as well?

Hurricanes with an outflow pattern that strong tends to fight off wind shear very well. Matthew last year was under 15-20kts of shear all the time while rapid intensifying. So shear probably won't be much of an issue once it reach the Bahamas.

Wonderful. I am scared for you guys in FL. Please get out if you can, please.

I'm staying put. I left Walmart after buying things for work and people were returning water and batteries. About 8 people were in the return line. This was at the port orange Walmart.

[weathaguyry]

How does damage look on the Islands? By the pictures I looked at before, it appears that most concrete structures made it out ok, but other structures did not.

[NDG]

St Thomas now gusting to 85 mph!

Conditions at: TIST observed 06 September 2017 15:25 UTC
Temperature: 26.1°C (79°F)
Dewpoint: 25.6°C (78°F) [RH = 97%]
Pressure (altimeter): missing
Winds: from the NW (320 degrees) at 45 MPH (39 knots; 20.3 m/s)
gusting to 85 MPH (74 knots; 38.5 m/s)
Visibility: 0.75 miles (1.21 km)
Ceiling: 1600 feet AGL
Clouds: overcast cloud deck at 1600 feet AGL
Present Weather: RA BR (rain, mist)
SOME DATA ABOVE MAY BE INACCURATE!!!
"$" is an indication the sensor requires maintenance

[Sanibel]

I've heard a report that the main government buildings on St Martin's were destroyed...Unconfirmed..

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

[txwatcher91]

Based on radar and Goes-16, it appears this may be turning with a little more northerly component in the last few frames. Would be great news for PR.

[Blown Away]

Could argue a little S of the forecast track, may wobble back...

Seriously?!!! Looks like it's straight down the middle to me. I guess if your counting hairs then maybe 1 hair south. Wouldn't even call it a wobble south, just 1 hair....

If you own property or are there now, a few miles S might make for a bad day...

[sweetpea]

I just spoke to my uncle in PR on FB, he is on the SE side of PR in Salinas. This is also were my dad is, my dad's street always floods. He said the wind is picking up and the streets are already starting to flood.

[Hurricane Andrew]

Hurricanes with an outflow pattern that strong tends to fight off wind shear very well. Matthew last year was under 15-20kts of shear all the time while rapid intensifying. So shear probably won't be much of an issue once it reach the Bahamas.

Wonderful. I am scared for you guys in FL. Please get out if you can, please.

I'm staying put. I left Walmart after buying things for work and people were returning water and batteries. About 8 people were in the return line. This was at the port orange Walmart.

People are RETURNING stuff?

This is like watching a slow-motion horror movie for me.