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 wunderkidcayman:
97L reminds me of Ivan somewhat
yes I know Ivan was furthe N when it passed Jamaica but generaly speeking

look at Ivans track when its in the Caribbean



now look at 97(PRE-Sean) models

IDK is it me or are the models for 97L acting like it's Aug. or Sept.?
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Quoting superpete:
sounds wonderful....


It is really a good time. Hoping Rina doesn't ruin it this year.
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Quoting wunderkidcayman:
97L reminds me of Ivan somewhat
yes I know Ivan was furthe N when it passed Jamaica but generaly speeking

look at Ivans track when its in the Caribbean



now look at 97(PRE-Sean) models

more like dennis to me
Member Since: August 23, 2011 Posts: 0 Comments: 1727
I had a great time at Fantasy Fest with my wife, and several other couples.

I'm in South Florida but if I had to choose this storm coming at me or going to the Keys I'd say let us deal with it.
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Quoting TampaSpin:
I believe it will cross the Yucatan and emerge in the BOC then make its turn.....that is my best guess...
disagree the most west rina will go is 10 to 20 miles inland as the high over the SE US immidiatly gets pushed about by a trough
Member Since: August 23, 2011 Posts: 0 Comments: 1727
97L reminds me of Ivan somewhat
yes I know Ivan was furthe N when it passed Jamaica but generaly speeking

look at Ivans track when its in the Caribbean



now look at 97(PRE-Sean) models

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Quoting WoodyFL:
There is even orange showing in the yellow. This would indicate exteme cold cloud tops. And I'm color blind, so if anyone sees anything different, please correct me. I'd be embarrassed as heck if they turned out to be blue.

Nope,Dat's correct
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97L starting too look better
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
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I believe it will cross the Yucatan and emerge in the BOC then make its turn.....that is my best guess...
Member Since: September 2, 2007 Posts: 179 Comments: 20448
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Anyway, I appreciate all the effort and input shared on these blogs. I just hope people are paying attention. I didn't know about it until a friend from NOLA sent me a "stay safe" msg about a hour ago. :-/
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Quoting wunderweatherman123:
not to interupt you guys but on the latest infrared looks like we got almost a complety eye wall. eye could pop out any hour

Still has about a quarter of an eyewall go to, as an hour or two ago, it had half an eyewall to go.

Member Since: July 6, 2010 Posts: 113 Comments: 32805
Quoting libertygirl:

A bunch of people coming down to live out their fantasy, on duval street for 48 hrs. things they prolly wouldn't do at home...and the rest just come to watch them. It's already starting. Mostly many highly intoxicated people, half naked people stimulating the local economy.
sounds wonderful....
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look the madels have been crap and spread out everywhere and some have the COC spread out too and plus with rina looking like it stall now moving N-NNE/NNW whatever we need to get the HH out there to find out
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Very healthy spiral band developing on the storm's eastern side.

Member Since: July 6, 2010 Posts: 113 Comments: 32805
not to interupt you guys but on the latest infrared looks like we got almost a complety eye wall. eye could pop out any hour
Member Since: August 23, 2011 Posts: 0 Comments: 1727
Fantasy Fest looks like Key West's version of Mardi Gras.
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642. MTWX
See the SHIPS brings 97L to Hurricane strength in 3 days...
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Quoting libertygirl:

A bunch of people coming down to live out their fantasy, on duval street for 48 hrs. things they prolly wouldn't do at home...and the rest just come to watch them. It's already starting. Mostly many highly intoxicated people, half naked people stimulating the local economy.
Well, then it could be a bad scene. Let's hope not. Sounds like a fun time.
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Quoting Darryl7:
Compared to what?


To yours. LOL.
Member Since: June 21, 2010 Posts: 0 Comments: 528
Quoting Darryl7:
Compared to what?

Yours.
Member Since: July 6, 2010 Posts: 113 Comments: 32805
Quoting dolphingalrules:


my house hit wilma..lost my patio..this time don't hit my house
...LOL...
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Quoting GTcooliebai:
I think the situation the GFS is showing is the trough out running Rina leaving the steering currents to collapse, kinda like Elena.


If it leave Rina behind then what happens with 97L as it approaches (and develops)? Could it be a Perfect Storm in the NW Caribbean...
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Quoting libertygirl:

A bunch of people coming down to live out their fantasy, on duval street for 48 hrs. things they prolly wouldn't do at home...and the rest just come to watch them. It's already starting. Mostly many highly intoxicated people, half naked people stimulating the local economy.


At least your explanation was civil.
Member Since: June 21, 2010 Posts: 0 Comments: 528
Quoting Clearwater1:
What is fantasy fest all about?

A bunch of people coming down to live out their fantasy, on duval street for 48 hrs. things they prolly wouldn't do at home...and the rest just come to watch them. It's already starting. Mostly many highly intoxicated people, half naked people stimulating the local economy.
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So, in the 8PM runs, we have two votes for taking off for Florida, two votes for a loop, and one vote for dying off in the YP.

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Quoting hurricaneben:


Wait do I see this right? 160 KNOTS??? How much is that in MPH, 180 or 185? This is not good.
That would be the CHIPS model you're referring too, it always seems to blow systems up for some reason. Here see if you can try and make sense of it :-P Link
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H.Rina's_12amGMT_ATCF : Starting 24Oct_12amGMT and ending 25Oct_12amGMT

The 4 eastern line-segments represent HurricaneRina's path,
the westernmost line-segment is the straightline projection for 25Oct_12amGMT,
the dot at MHIC is the endpoint of the straightline projection for 24Oct_6pmGMT,
and the sea-to-island dumbbell at 21.52n86.364w-ISJ is the same connected to its nearest airport for the 24Oct_12pmGMT*mapping.

Using straightline projection of the travel-speed&heading derived from the
ATCF coordinates spanning the 6hours between 6pmGMT then 12amGMT :
H.Rina's travel-speed was 2.5mph(4k/h) on a heading of 297.5degrees(WNW)
H.Rina was headed toward passing 8.9miles(14.3kilometres) north of the SwanIslands^Honduras ~19hours from now (though I wouldn't count on Rina continuing to move that slowly)

Copy&paste 21.52n86.364w-isj, mhic, 16.0n81.9w-16.5n82.2w, 16.5n82.2w-17.0n82.7w, 17.0n82.7w-17.1n83.0w, 17.1n83.0w-17.2n83.2w, 17.1n83.0w-17.545n83.894w into the GreatCircleMapper for more info

The previous mapping for 24Oct_6pmGMT

* The alteration of the endpoint of a TropicalCyclone's previous path also changes its previous travel-speed&heading, and the endpoint of its previous straightline projection...
...but I'm choosing to preserve the historicity of the previous straightline projections.

^ "In October 1998, Hurricane Mitch moved over Swan Island with winds of 180 mph."
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Quoting hurricaneben:


Wait do I see this right? 160 KNOTS??? How much is that in MPH, 180 or 185? This is not good.


That is 184.16 mph. Where did you see that?
Member Since: April 24, 2011 Posts: 1 Comments: 601
Quoting GTcooliebai:
I think the situation the GFS is showing is the trough out running Rina leaving the steering currents to collapse, kinda like Elena.


Yes, you are correct. That is what a few of them are showing. That is why the models confuse us sometimes. Quite often they reflect different scenarios, not simply because they disagree.
Member Since: April 24, 2011 Posts: 1 Comments: 601
Quoting libertygirl:
Lurker here from Key West. Not digging this at all, as this weekend, is Fantasy Fest. The island (low/mid keys) packed with people. I wonder how many are paying attention? They may start cancelling. Should Rina come in over the weekend, I hope it's a TS and not a repeat of Wilma. Not a whole lot of notice for evac and if you wait for the order, down here in KW, even without 10,000 extras for the fest, you are looking at a cluster to get to the mainland. On a good note, the weather has been "choice" since the 20" rainfall/flood. A/C hasn't been on since Thursday...80/73 high low. We are forecast for 30mph tomorrow and will likely start getting rain from Rina on Wed.
What is fantasy fest all about?
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Quoting wunderkidcayman:

true but now we are in D-min that mean 97L is doing great cause now you would see the convection to be suppressed but no it growing so as I said earler prob at 2 am maybe find 97L upped to 40-50%

yeah but not that slow


I think they'll up it 10% to 30%. Very interesting dynamic setting up with the interaction of Rina and 97L.
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Quoting GTcooliebai:
Intensity models for Rina:



Wait do I see this right? 160 KNOTS??? How much is that in MPH, 180 or 185? This is not good.
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Quoting WoodyFL:


It is a possibility. They are reliable models.
I think the situation the GFS is showing is the trough out running Rina leaving the steering currents to collapse, kinda like Elena.
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Lurker here from Key West. Not digging this at all, as this weekend, is Fantasy Fest. The island (low/mid keys) packed with people. I wonder how many are paying attention? They may start cancelling. Should Rina come in over the weekend, I hope it's a TS and not a repeat of Wilma. Not a whole lot of notice for evac and if you wait for the order, down here in KW, even without 10,000 extras for the fest, you are looking at a cluster to get to the mainland. On a good note, the weather has been "choice" since the 20" rainfall/flood. A/C hasn't been on since Thursday...80/73 high low. We are forecast for 30mph tomorrow and will likely start getting rain from Rina on Wed.
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Quoting WoodyFL:
This is 97L. It already has extreme cold cloud tops. Not unheard of, but unusual in something like this. I would not be surprised if the percentage goes up on this one as well. They do flare-up at times and then drop back down.




true but now we are in D-min that mean 97L is doing great cause now you would see the convection to be suppressed but no it growing so as I said earler prob at 2 am maybe find 97L upped to 40-50%
Quoting sunlinepr:


97L is slowly taking shape....


yeah but not that slow
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Quoting iamajeepmom:

Really, try to visualize Monroe County enforcing a mandatory evacuation of Fantasy Fest ... it would be difficult!


That will be a disaster if Rina comes through the Keys. There are going to be so many people there, getting off that island will be very time consuming. I imagine a lot of people would stay. I know I am watching it closely since I am supposed to head down there on Thursday to celebrate my birthday.
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Quoting GTcooliebai:
Oh ok, for some reason I never asked and always thought it stood for 6 o'clock and 12 o'clock.

Big UTC times:

0000Z = 8 p.m. EDT

0600Z = 2 a.m. EDT

1200Z = 8 a.m. EDT

1800Z = 2 p.m. EDT

1500Z = 11 a.m. EDT

2100Z = 5 p.m. EDT

0900Z = 5 a.m. EDT
Member Since: July 6, 2010 Posts: 113 Comments: 32805
is it time yet to go to publix, home depot and the liquor store..alot of vodka...
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Quoting TropicalAnalystwx13:

lol, yeah.

It took me a while to learn my UTC times, but I have them down now.
Oh ok, for some reason I never asked and always thought it stood for 6 o'clock and 12 o'clock.
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Everything is a possibility at this moment. It just all depends on time.
Member Since: June 21, 2010 Posts: 0 Comments: 528
Quoting A4Guy:
should we be putting much faith in those models that push Rina back south...basically looping her in the W Carib?


It is a possibility. They are reliable models.
Member Since: April 24, 2011 Posts: 1 Comments: 601
1. TROPICAL STORM RINA
FLIGHT ONE -- TEAL 70 FLIGHT TWO -- NOAA 42
A. 25/1800Z A. 26/0000Z
B. AFXXX 0418A RINA B. NOAA2 0518A RINA
C. 25/1500Z C. 25/2000Z
D. 17.7N 84.3W D. 17.8N 84.8W
E. 25/1730Z TO 25/2100Z E. 25/2230Z TO 26/0200Z
F. SFC TO 15,000 FT F. SFC TO 15,000 FT


thats what i saw
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Quoting GTcooliebai:
You answered my question just before I was about to ask you, which was does 06000Z mean 2am?

lol, yeah.

It took me a while to learn my UTC times, but I have them down now.
Member Since: July 6, 2010 Posts: 113 Comments: 32805

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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.

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