Rina rapidly intensifies into a hurricane

By: Dr. Jeff Masters , 7:59 PM GMT on October 24, 2011

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Rina is now a hurricane, just 21 hours after becoming a tropical depression. An Air Force Reserve hurricane hunter aircraft found winds of 75 mph--Category 1 hurricane strength--at 1:40 pm EDT in the north eyewall of Rina, using their SFMR surface wind instrument. Winds at flight level of 5,000 feet peaked at 78 mph, which typically translates to surface winds of 62 mph. On their second pass through the eye at 3:30 pm EDT, the winds were about 5 mph less, but the central pressure had fallen by two millibars, to 989 mb. Visible satellite loops show that Rina now has an eye, and the storm is steadily expanding in size and developing an impressive upper-level outflow channel to the north. Wind shear is a moderate 15 - 20 knots due to strong upper-level winds out of the southeast, and these winds are injecting dry air into Rina's southeast side, inhibiting heavy thunderstorm development there. Water temperatures are very warm, 29 - 30°C, and these warm waters extend to great depth.


Figure 1. Afternoon satellite image of Rina. An intense thunderstorm with a top that reaches into the stratosphere is visible on the southwest side of the eye. These "hot towers" are commonly seen in hurricanes undergoing rapid intensification.

Rina in historical context
Rina intensified into a hurricane just 21 hours after the first advisory was issued for it as a tropical depression. This is the second fastest such intensification since record keeping began in 1851. Hurricane Humberto of 2007 holds the Atlantic record for fastest intensification from first advisory issued to hurricane strength--18 hours. (Actually, Humberto did the feat in 14 1/4 hours, but this was rounded off to 18 hours in the final data base, which stores points every six hours). There have been six storms that accomplished the feat in 24 hours. Rina's formation brings this year's tally of hurricanes to six, which is average for an Atlantic hurricane season. The number of named storms this season is now seventeen, making it the 7th busiest Atlantic hurricane season since record keeping began in 1851. Only 2005, 1933, 1995, 1887, 2010, and 1969 had more named storms. However, 2011 has had an unusually low percentage of its named storms reach hurricane strength. Only 35% of this year's named storms have made it to hurricane strength, and normally 55 - 60% of all named storms intensify to hurricane strength in the Atlantic. The rare combination of near-record ocean temperatures but unusually dry, stable air over the Atlantic is no doubt at least partially responsible for this very unusual occurrence.


Figure 2. Microwave satellite image from 11:39 am EDT October 24, 2011, showing that Rina had a partially complete eyewall, which was open on the east side. Image credit: Navy Research Lab, Monterey.

Forecast for Rina
The hurricane hunters found an elliptical eyewall that had a gap in it during their 3:30 pm eye penetration. The aircraft measured a temperature difference of 6°C between the eye and the region outside the eye, which is difficult to get unless an eyewall is on its way to completion. Rina will need to complete its eyewall if it is to intensify into a major hurricane. Given the fact wind shear is not expected to increase until Wednesday, Rina has a 2-day period to close off an eyewall and intensify, and it will probably reach Category 3 or Category 4 strength by Wednesday. On Wednesday, Rina will encounter a dry airmass with high wind shear that lies over the extreme northwestern Caribbean. These conditions should weaken the hurricane, but Rina could still be a major hurricane if it makes landfall in the Yucatan Peninsula on Wednesday or Thursday.

A trough of low pressure is predicted to pass to the north of Rina late this week, and now that the hurricane is expected to be a Category 2 or stronger storm, the chances for Rina to make it farther north and affect the Florida Keys and Southwest Florida have increased. The latest 8 am EDT runs of the GFDL and HWRF models both predict that Rina will pass through the Yucatan Channel on Thursday and make landfall on Friday in the Florida Keys or extreme Southwest Florida, south of Naples. The NOGAPS and GFS models predict a weaker storm, and keep Rina trapped in the Caribbean. I think it is more likely that Rina will pass through the Keys. If Rina does make it to the Keys, it would likely be as a tropical storm, since wind shear, dry air, and possible land interaction with Western Cuba and Mexico would potentially knock down the storm's strength. Heavy rains from Rina should begin affecting Mexico's Yucatan Peninsula, northern Belize, and extreme Western Cuba on Wednesday. Rina's intensification into a hurricane over the Western Caribbean during the last half of October bring to mind Hurricane Wilma, which also performed such a feat in 2005. Wilma went on to become a Category 5 monster, the strongest Atlantic hurricane of all-time. I don't think Rina will be another Wilma, even though the ocean temperatures and total heat content are similar to what Wilma experienced. Wilma had nearly ideal upper-level atmospheric conditions with an anticyclone aloft and light wind shear, under 5 knots. Rina is experiencing 15 - 20 knots of wind shear and is also a smaller storm, and is thus more vulnerable to the effects of wind shear and dry air.

97L approaching ABC islands
A broad region of low pressure approaching the ABC islands of Aruba, Bonaire, and Curacao (Invest 97L), is moving west-northwest at 10 mph. Heavy thunderstorm activity has increased today, but the activity is not organized into spiral bands, as is apparent from Curacao radar. 97L is surrounded by a large region of dry air, and this dry air will retard development. 97L is under low wind shear less than 10 knots, and this shear is expected to remain low through Thursday. By the time 97L reaches the region between Jamaica and Nicaragua in the Central Caribbean on Thursday or Friday, the storm should find a moister environment, and could develop into a tropical depression. However, none of the reliable models are predicting that 97L will develop. NHC is giving 97L just a 10% chance of developing into a tropical depression by Wednesday. I put the odds higher, at 20%.

Jeff Masters

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Quoting WeatherNerdPR:
HURRICANE RINA?
That was fast. Good Afternoon.

Exactly what I thought.
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163. Gorty
Quoting weatherbro:


Upstate New England might see some as well this weekend.


Southern New England also but eastern New England as per the latest GFS will get hit the hardest (Eastern MA and RI are included).
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Quoting scott39:
When I started watching Rina about 5am this morning, it looked like something was up with her starting to organizing better. Then as the hours went by, you didnt have to know a whole lot about TC formation to know that she was organizing rapidly. I left about 10am and when I check back at 3:30pm she is a hurricane. Im concerned that this is going to be bad for some.

Not only mexico, but also the US.
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HURRICANE RINA?
That was fast. Good Afternoon.
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Quoting ProgressivePulse:


However, now that I have said that it will probably dissipate. Not likely unfortunately, she's on a run for sure. Rina seems to have that against all odds attitude observed in only a small percentage of cyclones per year.
When I started watching Rina about 5am this morning, it looked like something was up with her starting to organize better. Then as the hours went by, you didnt have to know a whole lot about TC formation to know that she was organizing rapidly. I left about 10am and when I check back at 3:30pm she is a hurricane. Im concerned that this is going to be bad for some.
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Quoting TropicalAnalystwx13:
On a totally non-tropical weather note, Colorado will see its first real Winter storm this season...Winter Storm Watches are in effect for the Denver area.



Upstate New England might see some as well this weekend.
Member Since: May 26, 2007 Posts: 47 Comments: 1271
Would the blogger from last night that posted "I just got off a conference call with ""MY BOY"" at NHC, and he said that this system is dead in the water" please step forward. Ha. Conference call
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Quoting TropicalAnalystwx13:

The system is very elongated, with a broad area of low pressure. There is no way this is getting even an Orange Circle at the 8PM or even 2AM TWO.


yes ok it is elongated but it can change reason also why I sayit could is that convection is increasing and because its doing that it creating a moisture field to protect it from dry air it has a huge ULAC right over it and it has a LLC however it elongated but as I said that can change
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Quoting MarcoIslandCat5:
My forecast is a cat 1 low end cat 2 making landfall around everglades city, What are te thought's off you guys??

High end cat 2 for me, I might change it, it depends.
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Quoting Articuno:

3 words:
Wilma-like intensification.
I have to admit im kinda in shock. I dont think it will get that strong but it was very fast. Looks great on sat to.
Link

Could get to a cat 4.
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Waiting on my Cold Front this week to plunge SE TX near 40 degrees
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My forecast is a cat 1 low end cat 2 making landfall around everglades city, What are te thought's off you guys??
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Dunno... based on what I see with all available models from 18Z, the track the NHC has is good through about 48 hours, but is far (and I mean FAR) south of the other available guidance at that point. There does seem to be better agreement in the models toward a South Florida/Keys event... but like the NHC points out, consistency is key. Until the consistency issues get worked out, expect only minor tweaks to days 4-5 in the forecast track. JMO
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Quoting hurricanehunter27:
Wow last i checked this was td18.

3 words:
Wilma-like intensification.
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Guys I'm afraid that Rina is turning into a monster in front of our eyes.This was not a surprise as I came on here earlier and stated that if Rina takes advantage of those sst with heat content and the upper level high over her then she will intensify fast.South florida watch out.
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Wow last i checked this was td18.
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I can't remember how I found my avatar, it's deep in the NHC site.
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Quoting TropicalAnalystwx13:

Popcorn is horrible.
Lol
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Quoting wunderweatherman123:
after rita scrapes or makes landfall in the yucatan where will she go next?
a: east back into the carribean
b: ene towards cuba
c: ne/ene towards the Florida keys
d: South florida
im thinking C or D and intensity should be around 80mph as the Subtropical jet rips her apart

I say A as I said just a few mins ago forecast will lie between the OFCI and the AVNO/GFS
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Quoting TropicalAnalystwx13:

Popcorn is horrible.

I disagree.
:P
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Quoting weatherbro:


I go with the Euro which deepens it.

Same here, but I'm thinking more with the NAM, which tends to do very well during the winter. (which also speeds it up, but with a little less deepening)
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Quoting MiamiHurricanes09:
My avatar is 3D...you should try it out LOL.
3-D does take the experience up quite a few notches!
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Quoting Articuno:

Eye seems to be clearing possibly?
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Quoting GeoffreyWPB:


I wouldn't be surprised if it reached Cat. 4 status before it starts to wind down.

I agree.
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Quoting wunderkidcayman:

bet you have no reason to say that

I say 40% the highest

The system is very elongated, with a broad area of low pressure. There is no way this is getting even an Orange Circle at the 8PM or even 2AM TWO.
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Quoting GeoffreyWPB:


I wouldn't be surprised if it reached Cat. 4 status before it starts to wind down.

Or the dreaded Cat. 5
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Quoting cchsweatherman:
For the first time in its lifetime, outflow is establishing itself over the southeast quadrant of the system meaning there is now outflow in all four quadrants. This is indicative of an improving upper level environment and one that should allow for continued strengthening.


I wouldn't be surprised if it reached Cat. 4 status before it starts to wind down.
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Quoting jeffs713:
Also.. in regards to the track uncertainty... The next front coming down into the Gulf Coast states is causing the problem. The models are predicting a strong and fast front, but the low that is spinning the front down is expected to deepen further west than normal, which isn't adding up to an especially fast frontal motion. The low hanging back west also means the upper trough will likely be hanging back. This upper trough is what should be ejecting Rina out to the NE.

So... if the upper trough lags, Rina can push more west before recurving out to the NE. If the trough is weak, the turn won't be as sharp. If the trough has more time to deepen, the turn can be sharper, and the forward motion will be faster, too. Oh... and the deeper the trough, the greater the shear.

Lots of moving parts. If you can do better, I'm sure the NWS and NHC would love to hire you.


I go with the Euro which deepens it further east.
Member Since: May 26, 2007 Posts: 47 Comments: 1271
So do we have to wait for the 8pm models to be more accurate since the rapid intensification?
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Quoting cchsweatherman:
For the first time in its lifetime, outflow is establishing itself over the southeast quadrant of the system meaning there is now outflow in all four quadrants. This is indicative of an improving upper level environment and one that should allow for continued strengthening.

and rapid strengthening.

Be sure to cover all bases ;)
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Quoting TropicalAnalystwx13:

Not even close, 20% at the absolute highest.

bet you have no reason to say that

I say 40% the highest
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after rita scrapes or makes landfall in the yucatan where will she go next?
a: east back into the carribean
b: ene towards cuba
c: ne/ene towards the Florida keys
d: South florida
im thinking C or D and intensity should be around 80mph as the Subtropical jet rips her apart
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Quoting scott39:
Go get some popcorn. You cant have 3-D and candy without popcorn.

Popcorn is horrible.
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For the first time in its lifetime, outflow is establishing itself over the southeast quadrant of the system meaning there is now outflow in all four quadrants. This is indicative of an improving upper level environment and one that should allow for continued strengthening.
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Like Wilma, South Florida will see this thing ramb through on a sharp NE track(minus the intensity). Followed by much cooler and drier air for Halloween Weekend!!
Member Since: May 26, 2007 Posts: 47 Comments: 1271
Quoting scott39:
Ive got my 3-D glasses, popcorn and candy!


However, now that I have said that it will probably dissipate. Not likely unfortunately, she's on a run for sure. Rina seems to have that against all odds attitude observed in only a small percentage of cyclones per year.
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Quoting TropicalAnalystwx13:

I've got my 3D glasses and candy.
Go get some popcorn. You cant have 3-D and candy without popcorn.
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Quoting wunderkidcayman:
also 97L looks to be doing very very very good maybe uped to 40% by 8pm

Not even close, 20% at the absolute highest.
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Quoting scott39:
Ive got my 3-D glasses, popcorn and candy!
My avatar is 3D...you should try it out LOL.
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Quoting jeffs713:
Post #111 was made to help clarify this. :)



yes I read your post and I still say: Oh Wow !!!
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also 97L looks to be doing very very very good maybe uped to 40% by 8pm
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Quoting njdevil:


Yeah, but that doesn't fit the WU Model AKA "It's going to absolutely destroy X!"


Very true. The WU model is a big reason I stopped coming by all the time, and trying to help.
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Quoting scott39:
Ive got my 3-D glasses, popcorn and candy!

I've got my 3D glasses and candy.
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12.1n60.7w, 12.1n62.4w have been re-evaluated&altered for Invest97L's_6pmGMT_ATCF
12.1n60.1w, 12.1n61.4w, 12.1n62.5w are now the most recent positions
Starting 23Oct_6pmGMT and ending 24Oct_6pmGMT

The 4 line-segments represent Invest97L's now eastward path.

Copy&paste gnd, uvf, 12.1n57.6w-12.1n59.0w, 12.1n59.0w-12.1n60.1w, 12.1n60.1w-12.1n61.4w, 12.1n61.4w-12.1n62.5w, lrv, bon, cur into the GreatCircleMapper for more info

The previous mapping for 24Oct_12pmGMT
Member Since: August 21, 2007 Posts: 0 Comments: 4860
yeah I know but anyway umm look at the HH data the vortex messages average the direction the their pointing at it averages N bound
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Quoting jeffs713:

They are just calling it like it is. Whenever you have a new system that is behaving unpredictably (likely due in part the the coarse resolution of the major global models), and the models are all over the place, its the best option. Which would you rather have: the NHC saying "our confidence is low in the long-term track", or "We are guessing the storm may end up in FL, or it could plow into Cuba. Or maybe Mexico. Outside chance of hitting Belize."

I'd much rather take them saying "our long-term confidence in the storm's track is low, because the models had entirely too much to drink last night."


Yeah, but that doesn't fit the WU Model AKA "It's going to absolutely destroy X!"

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Quoting MiamiHurricanes09:
Rina undoubtedly continues to intensify...the winds are just taking their time to catch up.

000
URNT12 KNHC 242104
VORTEX DATA MESSAGE AL182011
A. 24/20:42:20Z
B. 17 deg 09 min N
083 deg 03 min W
C. 850 mb 1310 m
D. 60 kt
E. 162 deg 10 nm
F. 272 deg 74 kt
G. 162 deg 10 nm
H. 987 mb
I. 17 C / 1523 m
J. 22 C / 1525 m
K. 14 C / NA
L. NA
M. NA
N. 12345 / 8
O. 0.02 / 2 nm
P. AF306 0218A RINA OB 19
MAX FL WIND 74 KT S QUAD 20:39:00Z
Strong banding around center from 300 to 020 degrees
;

We knew it had the potential...
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Quoting ProgressivePulse:
With the ridge currently building in overhead and improving structure of Rina, there should be quite a show tonight.
Ive got my 3-D glasses, popcorn and candy!
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Quoting WeatherfanPR:


OMG, they are the experts and their confidence is very low !!! Oh Wow !!!
Post #111 was made to help clarify this. :)
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.