ATL: IRMA - Post-Tropical - Discussion

[drewschmaltz]

As it relates to SST vs Haiyan. Haiyan had temperatures that peaked at 86 °F. Wikipedia says those temps extended to unusually great depth. Irma has SST of 87 °F and even 88°F in the keys. This station (https://tidesandcurrents.noaa.gov/stationhome.html?id=9761115) in Barbuda shows temps in front of Irma have cooled to 84.7°F. My question is this: is the current 3°F decrease in temp due primarily to the upwelling or the cooling of the water? Would you expect the water around Fl (especially around the keys) to cool more quickly, less quickly, or about the same as the water around Barbuda?

[Sciencerocks]

I wonder if some of these super-typhoons being compared with Irma actually higher winds. They are basing the winds on very accurate aircraft dropsondes. The Typhoon estimates were mostly satellite-derived. How do we know the winds weren't actually higher in those storms?

We don't, since the 1970s we only have Dvorak which was developed when there was a lot of WPac data to compare it too.

China's rich, Japans rich and South Korea's rich. I'd hope they could fund a recon program.

[FLeastcoast]

Creepy dead calm again here tonight with the crickets like last night...You can see the gradient delineation in the direction of Irma in the thin cirrus in the full moon...


Getting mother out tomorrow and up to Charleston...Too risky to chance...

I will be on the road right with you...heading to ga and then next day to knoxville...hopefully it is a safe choice. best wishes to you and your family

[CrazyC83]

For perspective: we saw incredible videos out of Rockport, TX from storm chasers 11 days ago in Harvey.

What Barbuda is about to experience will make that look like a summer breeze. Winds 50 mph stronger and with far, far more force.

[eastcoastFL]

Current Multiplatform Tropical Cyclone Surface Winds Analysis Chart:


http://www.ssd.noaa.gov/PS/TROP/mtcswa. ... 17&id=IRMA

[CrazyC83]

000
URNT15 KNHC 060338
AF305 1111A IRMA HDOB 37 20170906
032830 1702N 06040W 6968 03082 9985 +083 +053 202069 071 055 004 00
032900 1701N 06039W 6966 03088 9985 +088 +051 201066 068 054 004 00
032930 1700N 06038W 6972 03087 0005 +076 +050 203066 067 055 005 00
033000 1659N 06037W 6965 03099 0005 +080 +049 204065 066 055 004 00
033030 1657N 06036W 6966 03099 9994 +092 +047 203063 064 052 002 00
033100 1656N 06035W 6967 03103 9993 +095 +046 202062 063 049 002 00
033130 1655N 06034W 6966 03107 9996 +096 +045 201060 061 047 002 00
033200 1654N 06033W 6973 03100 0000 +095 +048 203059 060 046 003 00
033230 1653N 06032W 6969 03110 0002 +097 +051 203057 058 045 002 00
033300 1652N 06031W 6966 03119 0003 +099 +053 204056 058 046 002 00
033330 1651N 06030W 6966 03121 0003 +101 +054 201055 057 046 003 00
033400 1650N 06028W 6967 03123 0002 +106 +056 198055 056 045 002 00
033430 1649N 06027W 6969 03122 0000 +110 +057 198054 056 045 002 00
033500 1647N 06026W 6969 03126 0011 +105 +058 198052 053 043 002 00
033530 1646N 06025W 6968 03130 0013 +105 +061 194051 052 045 001 00
033600 1645N 06024W 6965 03134 0012 +106 +064 195050 051 043 002 00
033630 1644N 06023W 6967 03133 0010 +109 +066 194051 052 040 003 00
033700 1643N 06022W 6963 03141 0012 +107 +068 194052 052 040 002 00
033730 1642N 06021W 6970 03133 0014 +109 +068 194050 052 040 004 00
033800 1641N 06020W 6966 03140 0016 +110 +068 197051 052 038 004 00
$$
;

[CrazyC83]

000
URNT12 KNHC 060335
VORTEX DATA MESSAGE AL112017
A. 06/03:11:00Z
B. 17 deg 27 min N
061 deg 10 min W
C. 700 mb 2384 m
D. 153 kt
E. 314 deg 12 nm
F. 046 deg 148 kt
G. 315 deg 13 nm
H. 918 mb
I. 9 C / 3048 m
J. 23 C / 3052 m
K. 9 C / NA
L. CLOSED
M. C20
N. 12345 / 7
O. 0.02 / 1 nm
P. AF305 1111A IRMA OB 19
MAX FL WIND 163 KT 071 / 21 NM 01:59:00Z
MAX OUTBOUND FL WIND 154 KT 117 / 9 NM 03:18:00Z
CNTR DROPSONDE SFC WIND 195 / 11 KT
;

[Hurrilurker]

Are these models being initialized right? The reason I ask is that the 00Z GFS is showing 928 pressure after 18 hours. At the current time the pressure seems to be about 918mb (I'm looking at the latest recon data), and there is very little land interaction in the next 18 hours. And, with each recon fix, the pressure has still been steadily dropping. So why would it raise ~10mb in the next 18 hours?

[Ptarmigan]

It is going to be a long night for them.

[SootyTern]

Can someone explain the NHC 11PM advisory weakens Irma to 140MPH in the Florida Keys. Is there going to be shear? Are they forecasting Cuba to disrupt the core? Are they afraid to predict a Cat 5 on landfall in Florida?

It just doesn't make sense considering the oceanic heat content around South Florida is the highest in the entire Atlantic Basin. If Irma did 185MPH where he is now, there's no reason he can't do 200 in the Gulf Stream waters that are warmer.

If Irma doesn't hit Cuba, are they just praying for an eyewall replacement cycle? What's preventing a Cat 5 Florida landfall?

I hope she is only 140 at landfall.

I can't believe I just had to say that

[PandaCitrus]

Western Eyewall approaching. The buoy near Barbuda is reporting 42 sustained, 64 gusts.

http://www.wrh.noaa.gov/mesowest/getobe ... m=12&raw=0

The energy is all in the eyewall. This is a tightly wound monster.

 https://twitter.com/JohnMoralesNBC6/status/905275129055326210

[CrazyC83]

000
URNT15 KNHC 060347
AF305 1111A IRMA HDOB 38 20170906
033830 1639N 06019W 6963 03143 0019 +107 +068 198051 052 039 003 00
033900 1638N 06018W 6967 03146 0028 +102 +070 199048 049 038 002 00
033930 1637N 06016W 6963 03151 0028 +105 +071 199047 048 039 002 00
034000 1636N 06015W 6967 03144 0025 +106 +071 195046 047 038 002 00
034030 1635N 06014W 6966 03145 0028 +105 +072 195045 045 038 002 00
034100 1634N 06013W 6965 03147 0030 +104 +072 194044 045 037 002 00
034130 1633N 06012W 6963 03154 0031 +104 +072 194044 044 037 002 00
034200 1631N 06011W 6970 03145 0027 +108 +071 196043 044 036 003 03
034230 1631N 06009W 6971 03144 0028 +109 +072 194044 045 034 002 00
034300 1630N 06008W 6964 03156 0032 +105 +073 195043 044 034 001 00
034330 1629N 06006W 6963 03155 0040 +098 +073 194043 044 035 004 00
034400 1628N 06005W 6970 03150 0044 +098 +074 195043 044 035 006 03
034430 1627N 06004W 6963 03161 0050 +094 +074 200040 042 037 003 00
034500 1625N 06003W 6971 03150 0046 +099 +074 201040 040 038 003 00
034530 1624N 06003W 6970 03150 0040 +103 +073 200040 041 038 002 00
034600 1623N 06002W 6971 03152 0053 +094 +073 198041 041 038 002 00
034630 1621N 06001W 6963 03161 0046 +101 +073 203040 040 038 002 00
034700 1620N 06000W 6966 03164 0050 +100 +072 202038 039 038 001 00
034730 1619N 05959W 6969 03160 0049 +102 +072 203038 038 038 001 00
034800 1618N 05958W 6967 03163 0046 +105 +072 203039 039 036 002 00
$$
;

[mrbagyo]

outer limit of the eyewall is now lashing Barbuda, 30 mins more and they will be well inside that horrendous core

[eastcoastFL]

Barbuda not too far from the western eye wall now on radar

http://www.meteofrance.gp/previsions-me ... r/caraibes

[PandaCitrus]

Antigua may escape the eyewall to the south barely. They may only receive Cat 1 conditions given how tightly wound up the core is.

[Sanibel]

The noise this will make on Barbuda will go above wind scream and become a droning hum...

[drewschmaltz]

For perspective: we saw incredible videos out of Rockport, TX from storm chasers 11 days ago in Harvey.

What Barbuda is about to experience will make that look like a summer breeze. Winds 50 mph stronger and with far, far more force.

I'm sure plenty of people know this: but of the specifics I was unsure. The pressure per square ft of wind is given by the equation:

(wind_speed^2) * 0.0027

So, lets do the math.

Borrowing from wikipedia again, I see that: "Wind gusts were observed up to 132 mph" for Harvey.

132^2 * .0027 = 47 lbs per square ft

I don't see gusts for Irma, but let's assume 200 mph.

200^2 * .0027 = 108 lbs per square ft

Looks like if you stood outside and faced the wind in Harvey, you'd have about 150lbs of pressure pushing you back.

And, if you were on Barbuda right now and did the same thing, you'd have 325lbs of pressure pushing you back.

A 55% increase in wind yielded a 129% increase in force... if my math is correct.

[Snowman67]

Western eye wall now hitting east coast of Barbuda.

http://barbadosweather.org/Composite/ki ... site=Sabre

[Aric Dunn]

aannndd here it come for barbuda.. can only imagine..Im making plans to fly to florida but a deep tropics hurricane like this.. sheesh..

[Evil Jeremy]

aannndd here it come for barbuda.. can only imagine..Im making plans to fly to florida but a deep tropics hurricane like this.. sheesh..

Where in FL would you go?