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 TropicalWeatherGrl88:
Please correct me if I am wrong, but the new information on Hurricane Rina will not be in the 18z model run?

???
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Quoting TropicalWeatherGrl88:
Please correct me if I am wrong, but the new information on Hurricane Rina will not be in the 18z model run?


I am pretty sure only the 0z runs will have the recon data incorporated.
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Quoting thebandman:
Will Invest 97 have any impact on Rina? Just seem like the tow of them are going to meet.

Highly unlikely, they are thousands of miles ahead of eachother.
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It really amuses me to see all these folks in their landlocked states saying they wish it would his this piece of land etc etc.....not easy to say that when you are the one staring down the barrel of this thing....



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I see Rina is a hurricane. Heh, this clearly wasn't one of my better forecasts. But that's why I love this field. ;)
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Please correct me if I am wrong, but the new information on Hurricane Rina will not be in the 18z model run?
Member Since: September 17, 2010 Posts: 0 Comments: 216
Where'd everybody go?
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On a side note--and forgive me if this has already been covered--NWS Miami has confirmed via report that last week's Broward County tornado was definitely an EF-2:

...TORNADO CONFIRMED IN THE SUNRISE/PLANTATION AREA...

A STORM SURVEY WAS CONDUCTED TODAY BY THE NATIONAL WEATHER SERVICE
IN MIAMI. THE SURVEY TEAM CONCLUDED THAT A TORNADO STRUCK THE
SUNRISE/PLANTATION AREA AT AROUND 10:07 PM EDT TUESDAY, OCTOBER
18TH. HERE ARE THE DETAILS:

MAXIMUM RATING: EF-2
MAXIMUM WINDS: 120 MPH
PATH LENGTH: 1.11 MILES
MAX WIDTH: 125 YARDS

THE TORNADO BEGAN AT NW 135TH AVENUE AND NW 3RD STREET IN PLANTATION
AND ENDED AT NW 13TH STREET AND NW 133RD AVENUE IN SUNRISE.

DAMAGE THROUGHOUT MOST OF THE PATH WAS OF EF-1 INTENSITY WITH WINDS
OF 95-110 MPH. MORE SIGNIFICANT DAMAGE WAS SEEN OVER A SMALL PORTION
OF THE PATH, BETWEEN 8TH AND 10TH STREET JUST WEST OF 133RD AVENUE,
AND WAS RATED AS EF-2 WITH A MAXIMUM WIND ESTIMATED AT 120 MPH.

UP TO 50 HOMES WERE DAMAGED ALONG THE TORNADO'S PATH WITH DAMAGE TO
ROOFS, GARAGE DOORS, AND WINDOWS. AT LEAST A DOZEN HOMES HAD
SIGNIFICANT TO SEVERE DAMAGE. ROOFS OF TWO HOMES WERE COMPLETELY
REMOVED. TWO TRAILER HOMES WERE SHIFTED OFF THEIR FOUNDATIONS WITH
MOST OF THE WALLS COLLAPSED. ONLY A FEW MINOR INJURIES WERE REPORTED, CONSISTING
OF CUTS AND BRUISES.
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Quoting Autistic2:
OK,

We here in St. Augustine can "just forget about" getting any rain from Rina?

Correct?

Yup.
I am sure of it.
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OK,

We here in St. Augustine can "just forget about" getting any rain from Rina?

Correct?
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When is the front forecasted to dip that far S and pull Rina to the N and then NE?
Member Since: June 13, 2009 Posts: 0 Comments: 6871
97L looks happy. But disorganized.
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Wow! Last I checked at 6am this morning we had TD18. A hurricane already??
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Quoting Some1Has2BtheRookie:


I guess that not everyone has heard they have 4D out now. ... I watch commercials. ;-)
I knew I should have waited to buy!
Member Since: June 13, 2009 Posts: 0 Comments: 6871
Wait for the 8pm models for any guidance.
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Will Invest 97 have any impact on Rina? Just seem like the tow of them are going to meet.
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Quoting DavidHOUTX:
Is it me or does this show a nice cold blast with a low pressure move through SE Texas around Nov 1?

http://raleighwx.americanwx.com/models/euro/12zeu rotropical500mbSLP_loop.html


No, it's not just you. That ULL should develop over the Rockies and reinforce the cold front that's headed down toward the southeast Friday and Saturday. My feeling is that this will create a really hostile environment if she turns east in the Gulf. My immediate interest in these fronts is the amount of moisture return we get from the Gulf and the amount of shear and cape the fronts produce. We are about to head into our secondary period of severe weather in Alabama, and this set up could mean trouble for use Late Friday into Saturday. High was 83 today, so there should be some warm air for the systems to work with if we can get enough return air off the Gulf to moisten up the environment.
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Quoting RitaEvac:
There better be a nice squall line and widespread rain over TX with this strong front coming

I agree, hope we get some rain from this oddball system!
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I say/hope Rina doesnt hit any land! Turn before the Yucatan and die in the Eastern GOM.
Member Since: June 13, 2009 Posts: 0 Comments: 6871
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Quoting wunderkidcayman:
I was just looking at the vis sat loop and look like rina COC is at 17.5N 83.1W


I'd say its close to that also
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Quoting wunderkidcayman:
I was just looking at the vis sat loop and look like rina COC is at 17.5N 83.1W

I had 83.2W but I pretty much agree.
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There better be a nice squall line and widespread rain over TX with this strong front coming
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I was just looking at the vis sat loop and look like rina COC is at 17.5N 83.1W
Member Since: June 13, 2009 Posts: 2 Comments: 12180
Quoting ANOTHERBADFORCAST:
the local mets here at 5pm took rina out of the forcast for central florida could that be true?


Not sure which channel you watch, but none of them ever put Rina in the forecast to begin with. They have said that we would need to keep an eye on her. However, I don't think she'll come across Central Florida, but if she comes into South Florida or the Keys, we could have some peripheral affects from her. All the local mets have been mentioning is slight rain chances headed into the weekend. And they still say we need to keep an eye on her.
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Quoting wunderkidcayman:

I am think the best chances of Rina of hitting is when rina turns around after its off the coast and head between Grand Cayman and the isles of youth or if rina gets stronger it will most likely slow down for a while and then turn N-NNE cause there is still that gap for the storm to go through and the stronger it get the more likely it going to go through that gap


I can agree with that...

I hope not though. I'd really like to see Rina do no harm..
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Quoting Dakster:


What is the 4th Dimension? Taste?


I would say "time". I believe it is Best Buy that has commercial where someone just gets a new 3D TV and a little girl is dancing around and saying, "Silly head. You could have got 4D.". ... Yes, I scratched my head too. "time", is the fourth dimension. Trying putting time into your glasses?

I hear that satellite images of storms really stand out! lol
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Quoting ANOTHERBADFORCAST:
can rina hit central florida? the local mets here are saying no

maybe some bands possible, but that's if it hits south fl
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Quoting ANOTHERBADFORCAST:
the local mets here at 5pm took rina out of the forcast for central florida could that be true?


I'm guessing it's not, because it isn't, so it wasn't.

W Cent. and SW FL area NWS discussion:

THE OTHER FORECAST
UNCERTAINTY IS THE DEVELOPMENT AND EVENTUAL MOVEMENT OF RINA.
MODEL FORECASTS ARE HIGHLY VARIABLE...BUT MOST DO INDICATE SOME
DEEP MOISTURE MOVING NORTH AHEAD OF THE FRONT THURSDAY AND FRIDAY
BRINGING THE CHANCE OF SHOWERS TO THE AREA.
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Quoting Articuno:
Hurricane rina models




the nhc is to aggresive on their east turn
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Quoting Dakster:


Define "real" effects please...

My brother went to watch a 4-D movie and when a man sneezed (or something like that) he felt a little bit of water.
IDK.
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Quoting Dakster:
Good Afternoon everyone... (or Morning or Night, depending on where in the world you are)

Ok, Cayman Islanders... We were talking about this yesterday. I would say your chances for a hit have increased (as have ours in South Florida).

Time to watch this one and the model runs.




I am think the best chances of Rina of hitting is when rina turns around after its off the coast and head between Grand Cayman and the isles of youth or if rina gets stronger it will most likely slow down for a while and then turn N-NNE cause there is still that gap for the storm to go through and the stronger it get the more likely it going to go through that gap
Member Since: June 13, 2009 Posts: 2 Comments: 12180
Quoting hurricanehunter27:
What is the shear expected to be in the Gulf when Rina arrives.


30-40Kts westerly Shear.
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Quoting Articuno:
4D is just 3D with real effects.


Define "real" effects please...
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Quoting hurricanehunter27:
What is the shear expected to be in the Gulf when Rina arrives.
50 knots. if she is at least a cat 2 when she enters and she is moving North East it wont weaken her much as Southwest shear and north east movement go well with eachother Example: Wilma actaully stregnthed to a cat 3 in 50 knots of shear as she was moving ne at 20mph.
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Quoting wxgeek723:


Time.


But in a TV Show there was always a "time" component, even in 2-D...

I guess we need 5-D... For taste and smell. Although some programs with those dimensions could get interesting..

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Is it me or does this show a nice cold blast with a low pressure move through SE Texas around Nov 1?

http://raleighwx.americanwx.com/models/euro/12zeu rotropical500mbSLP_loop.html
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What is the shear expected to be in the Gulf when Rina arrives.
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Quoting Dakster:


What is the 4th Dimension? Taste?


Touch! Lol
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4D is just 3D with real effects.
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Quoting Some1Has2BtheRookie:


I guess that not everyone has heard they have 4D out now. ... I watch commercials. ;-)


What is the 4th Dimension? Taste?
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Quoting RitaEvac:
Waiting on my Cold Front this week to plunge SE TX near 40 degrees


Me too!!!
Member Since: May 26, 2007 Posts: 47 Comments: 1331
Hurricane rina models

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Quoting scott39:
3-D does take the experience up quite a few notches!


I guess that not everyone has heard they have 4D out now. ... I watch commercials. ;-)
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Rina is like the perfect stereotype of a late season storm in an active year - her name is far down the list, she's sucking up all the energy in the Western Carib, she's leaving everybody dumbfounded, and she herself has no idea where she's going. Classic.
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impressive burst of convection around the center...hot tower?

Link
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Hurricane Rina forms, threatens to become a major!

Wow, that happened fast!
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Good Afternoon everyone... (or Morning or Night, depending on where in the world you are)

Ok, Cayman Islanders... We were talking about this yesterday. I would say your chances for a hit have increased (as have ours in South Florida).

Time to watch this one and the model runs.



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

Exactly what I thought.
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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.