ATL: IRMA - Post-Tropical - Discussion

[Extratropical94]

Pressures down to 920mb per recon.

Pretty significant now. Just a very few hours ago at 927. then heard 925. If 920, then this could really take off. GFS on intensity seems outlandish. But, Irma is not your normal storm. This has unknown potential. Restrengthening in the Fl Straits......

Dropsonde just came in. 924 with 4 knots, so no real deepening between passes. The previous pass had 925 with 10 knots, which is 924 basically.

Extrapolated pressures can be decieving.

[Frank P]

last few loops of the IR sat loops hint of perhaps a slow down? need more loops to confirm..

[Bolebuns]

Question: If the Keys get the dirty side of Irma, is there potential to alter the geography of the Keys...i.e. they could just disappear? I have never been there, but look small and the highest point is 8ft. With a huge surge plus wind driven waves, it seems like it could do lasting damage to the landscape. No?

[KBBOCA]

Could it be done....it looks like..

Looks to be opening it's larger eye now on IR.

Ah, by IT you mean the eyewall replacement? Sorry, was missing context on the initial post!

[Centralflamama]

Watching the weather channel, I was stunned to hear people were just leaving tree limbs on the roads. In a hurricane that is going to become a projectile and cause unnecessary damage.

I really am hoping everyone heeds the warnings about Irma and gets out while they can.

My neighbors had their giant oaks trimmed and they let the people leave two giant piles at the end of their driveway. I'm furious, so rude.

That really does sound crazy, is there anything you can do insurance wise to try and protect yourself in the case some of it smashes through your house?

I have no idea. I'm going to take pictures of my house before and after and the tree limb piles in the morning before we leave. I am sure it would be impossible to pin it on them unless no other trees have a ton of damage, if that makes sense?

[PTPatrick]

She's also starting to stroke up some colder cloud tops.

[Kat5]

last few loops of the IR sat loops hint of perhaps a slow down? need more loops to confirm..

Another eye illusion. She's working out the post EWRC issues, I'm more inclined to believe she might strengthen on her way to the panhandle.

[NDG]

Looking much better this evening, she looks to make landfall along the northern Cays of north central Cuba tonight.

[Aric Dunn]

Could it be done....it looks like..

I think it is done as well, but for the next 12hrs the Cuban coastline will probably keep Irma in check through dry air, indeed you can see this drier air bubble round the eye at times on the IR and then get mixed out by the eyewall convection.

Its going to get a solid 18hr window to strengthen and if it can avoid too much of Cuba then the inner core will be in a good position to strengthen. GFS 889mbs won't be far wrong if that happens.

Holy #$%@

I meant the ERC..

There is no dry air


Nothing holding it back exceot maybe a little land interaction if it gets closer to cuba

[northjaxpro]

Pressures down to 920mb per recon.

Pretty significant now. Just a very few hours ago at 927. then heard 925. If 920, then this could really take off. GFS on intensity seems outlandish. But, Irma is not your normal storm. This has unknown potential. Restrengthening in the Fl Straits......

That is right. Pressure is falling again, which is a very ominous sign. She will be a Cat 5 again for certain later tonight imo. That is why the interaction with Cuba is critical to try to weaken the cyclone. It is going to be real close, but iI think it is more likely that Irma's eyewall will only graze the coast at best. I want to be wrong about this and hope the eye wall can penetrate into Cuba more, but it will be at that juncture when the turn north will commence as well. It will be close!

[NDG]

Pressures down to 920mb per recon.

Pretty significant now. Just a very few hours ago at 927. then heard 925. If 920, then this could really take off. GFS on intensity seems outlandish. But, Irma is not your normal storm. This has unknown potential. Restrengthening in the Fl Straits......

Dropsonde just came in. 924 with 4 knots, so no real deepening between passes. The previous pass had 925 with 10 knots, which is 924 basically.

Extrapolated pressures can be decieving.

The higher the recons fly the more off the extrap pressures are, at H70 I always add at least 4 mb to their extrap reading when they fly that high.

[KBBOCA]

I really hope and pray John Morales' message to folks who stayed on the Keys gets their attention, and that he'll save some lives with this:

 https://twitter.com/JohnMoralesNBC6/status/906290849432166402

[KWT]

Latest microwave.

https://ibb.co/iZrLKF

Given the eyewall is realtively weak on the SW side its impressive Irma is holding on as much as it is, I suspect that is probably solely due to taking in some drier air from Cuba.

Still hopefully the eyewall remains weaker down there, will mean probably cat-3 type winds down there, which obviously is still horrific, but not quite the brutal 4/5 winds that may be felt elsewhere this weekend.

I dont know where this "dry air" stuff is coming from. Dry air doesnt magically appear in the center it has to be pulled into the circulation from outer bands and there is no evidence that has happened. Most fluctuations at this point are eye wall dynamics. Think the spinning skater when they pull in their arms they spin faster. Well after an EWRC the eye expands as does the the wind field...the skater's arms go out again. It then pulls in again and spin increases.
Its not dry air

Its not 'dry air' per say, its subsidence coming from the drier air over Cuba. Its really obvious when you look at a high resolution IR loop and watch the drier slots rotate around the eye then mix out. Dry air isn't quite right, but there is subsidence which is preventing the eye from getting that real classic look and why you keep seeing these little dry slots whipping around. The inner eyewall is gone now so its not EWRC related. Once it moves from Cuba that issue will be long gone.

[Sciencerocks]

000
URNT15 KWBC 082259
NOAA2 2311A IRMA HDOB 22 20170908
224930 2146N 07603W 6968 03021 9876 +108 //// 195073 074 054 006 01
225000 2145N 07601W 6966 03028 9883 +108 //// 197071 072 056 005 01
225030 2145N 07559W 6956 03046 9891 +106 //// 199071 071 055 005 01
225100 2144N 07558W 6969 03034 9900 +103 //// 199071 071 056 003 01
225130 2143N 07556W 6967 03042 9904 +103 //// 199069 070 054 004 01
225200 2142N 07554W 6967 03044 9906 +105 +101 197067 067 053 003 00
225230 2141N 07552W 6958 03057 9910 +106 +096 198067 068 052 003 00
225300 2140N 07551W 6953 03071 9918 +107 +091 198067 067 052 003 00
225330 2139N 07549W 6956 03072 9924 +106 +091 199065 066 049 003 00
225400 2138N 07547W 6958 03075 9927 +108 +092 200065 067 048 002 00
225430 2137N 07545W 6953 03084 9932 +108 +095 203069 070 047 003 00
225500 2136N 07543W 6967 03074 9939 +106 +105 203066 066 048 002 00
225530 2136N 07541W 6967 03079 9946 +104 //// 201063 065 047 002 01
225600 2135N 07539W 6967 03080 9954 +101 //// 199059 059 046 003 01
225630 2134N 07537W 6957 03096 9950 +105 //// 195062 063 044 006 01
225700 2133N 07535W 6963 03092 9960 +100 //// 193059 061 039 010 01
225730 2132N 07533W 6968 03086 9966 +098 //// 194058 059 038 010 01
225800 2132N 07531W 6956 03108 9967 +099 //// 194061 063 039 009 01
225830 2131N 07530W 6958 03106 9975 +098 +095 194062 063 040 005 00
225900 2130N 07528W 6959 03108 9980 +097 +086 195063 063 039 005 00

[Extratropical94]

Question: If the Keys get the dirty side of Irma, is there potential to alter the geography of the Keys...i.e. they could just disappear? I have never been there, but look small and the highest point is 8ft. With a huge surge plus wind driven waves, it seems like it could do lasting damage to the landscape. No?

It's not impossible that some of the geography that is not reinforced might be altered. Hurricanes are known for being able to carve sounds/waterways through barrier islands and eroding/moving areas of sediment. So I don't see why this would be impossible in the Keys.

[KBBOCA]

 https://twitter.com/TropicalTidbits/status/906291703711227904




Levi Cowan‏ @TropicalTidbits 4m4 minutes ago

New recon passes into #Irma showing a falling pressure again, indicating that Irma may be starting to gradually strengthen once more.

[Nimbus]

Given the eyewall is realtively weak on the SW side its impressive Irma is holding on as much as it is, I suspect that is probably solely due to taking in some drier air from Cuba.

Still hopefully the eyewall remains weaker down there, will mean probably cat-3 type winds down there, which obviously is still horrific, but not quite the brutal 4/5 winds that may be felt elsewhere this weekend.

I dont know where this "dry air" stuff is coming from. Dry air doesnt magically appear in the center it has to be pulled into the circulation from outer bands and there is no evidence that has happened. Most fluctuations at this point are eye wall dynamics. Think the spinning skater when they pull in their arms they spin faster. Well after an EWRC the eye expands as does the the wind field...the skater's arms go out again. It then pulls in again and spin increases.
Its not dry air

Its not 'dry air' per say, its subsidence coming from the drier air over Cuba. Its really obvious when you look at a high resolution IR loop and watch the drier slots rotate around the eye then mix out. Dry air isn't quite right, but there is subsidence which is preventing the eye from getting that real classic look and why you keep seeing these little dry slots whipping around. The inner eyewall is gone now so its not EWRC related. Once it moves from Cuba that issue will be long gone.

Its hard to differentiate the dry air slot from a north wobble of the true center.

[KBBOCA]

 https://twitter.com/TropicalTidbits/status/906292086298771456




Levi Cowan‏ @TropicalTidbits 3m3 minutes ago

Significant interaction of #Irma's core with #Cuba seems inevitable at this point. Large eyewall already nearing the coast.

[ScottNAtlanta]

Given the eyewall is realtively weak on the SW side its impressive Irma is holding on as much as it is, I suspect that is probably solely due to taking in some drier air from Cuba.

Still hopefully the eyewall remains weaker down there, will mean probably cat-3 type winds down there, which obviously is still horrific, but not quite the brutal 4/5 winds that may be felt elsewhere this weekend.

I dont know where this "dry air" stuff is coming from. Dry air doesnt magically appear in the center it has to be pulled into the circulation from outer bands and there is no evidence that has happened. Most fluctuations at this point are eye wall dynamics. Think the spinning skater when they pull in their arms they spin faster. Well after an EWRC the eye expands as does the the wind field...the skater's arms go out again. It then pulls in again and spin increases.
Its not dry air

Its not 'dry air' per say, its subsidence coming from the drier air over Cuba. Its really obvious when you look at a high resolution IR loop and watch the drier slots rotate around the eye then mix out. Dry air isn't quite right, but there is subsidence which is preventing the eye from getting that real classic look and why you keep seeing these little dry slots whipping around. The inner eyewall is gone now so its not EWRC related. Once it moves from Cuba that issue will be long gone.

Not to be argumentative, but any subsidence that is occurring is well away from the center. I will have to disagree with it being "solely" due to anything. Its mostly Eyewall dynamics right now

[Sciencerocks]

000
URNT15 KWBC 082309
NOAA2 2311A IRMA HDOB 23 20170908
225930 2129N 07526W 6970 03099 9985 +097 +082 196062 062 040 004 00
230000 2128N 07524W 6971 03096 9988 +096 +085 195062 063 039 004 00
230030 2127N 07522W 6953 03125 9988 +099 +088 192061 062 039 004 00
230100 2127N 07520W 6951 03132 9991 +100 +084 192056 058 039 004 00
230130 2126N 07518W 6957 03124 9998 +096 +082 185053 054 037 004 00
230200 2125N 07516W 6960 03123 0007 +091 +082 186054 054 036 005 00
230230 2124N 07515W 6959 03127 0004 +095 +081 190055 056 037 004 00
230300 2124N 07512W 6951 03137 0008 +092 +073 191057 057 036 004 03
230330 2125N 07510W 6958 03127 0006 +096 +067 192057 057 /// /// 03
230400 2127N 07509W 6969 03117 0008 +096 +066 191057 057 038 001 03
230430 2130N 07509W 6967 03122 0010 +096 +065 190058 058 038 002 00
230500 2132N 07509W 6965 03125 0009 +097 +064 189058 058 039 001 00
230530 2135N 07508W 6967 03122 0009 +097 +065 188059 060 039 001 00
230600 2137N 07508W 6967 03122 0010 +096 +068 186059 060 038 002 00
230630 2140N 07508W 6967 03122 0010 +095 +073 182058 058 040 002 00
230700 2143N 07507W 6967 03122 0004 +100 +076 180058 059 040 002 00
230730 2145N 07507W 6967 03121 0002 +101 +073 174059 061 041 002 00
230800 2148N 07507W 6968 03120 0001 +102 +071 171062 063 039 002 00
230830 2150N 07506W 6966 03122 9998 +104 +069 173063 064 040 002 00
230900 2153N 07506W 6967 03122 0004 +100 +072 174062 063 041 001 00