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 TampaSpin:






I am really confused with this one.....there was suppose to be a weak cold front move into Florida about Friday or Saturday but, when you look at the Temperature forecast for Tampa, the NWS in Tampa is not showing much of a cold front.....


Below is the 8am temp forecast starting on Friday thru Sunday.







Below is from WU for Tampa.......

Friday, 28

85 | 65 °F
Chance of T-storms
Chance of
Precipitation40%
Saturday, 29

81 | 58 °F
Partly Cloudy
Chance of
Precipitation10%
Sunday, 30

81 | 61 °F
Partly Cloudy
Chance of
Precipitation


They made a big mistake. The trough is much to amplified to keep temps a broke even. At the very least, we should see an exact repeat of what happened behind the last front lol.:)
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Quoting Thrawst:
Can anyone tell me how to put a profile picture on here? I've tried three times, and it hasn't worked.

Thanks in advance.

Step 1: Click on your current avatar.



Step 2: In the top right hand corner, choose "Upload Photos"



Step 3: Click browse, choose your picture, and hit okay. Then, on the right hand side, choose "This image is a "portrait" or for use on the blog"



Step 4: Scroll down, choose any random location on the map, and click Send..You will have to add a title though, which is on the top left.
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Quoting TampaSpin:






I am really confused with this one.....there was suppose to be a weak cold front move into Florida about Friday or Saturday but, when you look at the Temperature forecast for Tampa, the NWS in Tampa is not showing much of a cold front.....


Below is the 8am temp forecast starting on Friday thru Sunday.







Below is from WU for Tampa.......

Friday, 28

85 | 65 °F
Chance of T-storms
Chance of
Precipitation40%
Saturday, 29

81 | 58 °F
Partly Cloudy
Chance of
Precipitation10%
Sunday, 30

81 | 61 °F
Partly Cloudy
Chance of
Precipitation
.PREVIOUS LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...MID/UPPER
LEVEL TROUGH WILL BE SETTING UP OVER THE EASTERN U.S. DURING THE
PERIOD WITH THE TROUGH AXIS FORECAST TO MOVE ACROSS FLORIDA FRIDAY
NIGHT AND SATURDAY. MEANWHILE AT THE SURFACE HIGH PRESSURE OVER
THE WESTERN ATLANTIC WILL RIDGE WESTWARD NORTH OF THE AREA ON
THURSDAY THEN A COLD FRONT ASSOCIATED WITH THE TROUGH WILL BE
MOVING THROUGH THE SOUTHEAST U.S. AND INTO FLORIDA. THE EXACT
TIMING OF THE FRONT CONTINUES TO VARY BETWEEN MODELS AND BETWEEN
MODEL RUNS...BUT APPEARS AT THIS TIME IT WILL MOVE ACROSS THE
REGION DURING FRIDAY NIGHT AND SATURDAY. 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. BEHIND THE FRONT HIGH
PRESSURE WILL BUILD IN OVER THE UPCOMING WEEKEND BRINGING SOME
DRIER AND SLIGHTLY COOLER AIR INTO THE REGION ON BREEZY NORTHERLY
WINDS. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL THURSDAY AND
FRIDAY THEN RETURN TO NEAR NORMAL OVER THE WEEKEND.
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Quoting cchsweatherman:


Now that my friends is the textbook definition of a CDO (Central Dense Overcast). Hurricane Rina impressing as the sun sets.



Looking at the current structure, it would not surprise me in the least if Rina were a CAT 3 tomorrow morning.
Member Since: August 19, 2005 Posts: 5 Comments: 5020
NO Sean would have the opposite affect on Rina....actually Rina could spin Sean around to Florida would be the likely thing if they got close enough.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
GIVEN THE EXTREMELY LARGE SPREAD IN THE GUIDANCE...AND THE POOR RUN
TO RUN CONSISTENCY...THERE IS MUCH LOWER THAN NORMAL CONFIDENCE IN
THE LONG-RANGE TRACK FORECAST OF RINA.


From the 5 p.m.

Looks like there's still a lot of leeway for change in the 4-5 day range.... and given challenges in quantifying trough strength at that range, it's not surprising we're seeing such a wide range.
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Quoting JNCali:
That is a great question! (wish I had the answer.. Taz? Levi?gulp...Reed?)

Where is Taz anyways?
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Whoa... this is forecast to become a cat 3??? I missed something since I was in here at 6 am this morning lol.
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Quoting yellowtail:
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....



i wish it would run up the gulf to texas and just before landfall degenerate to a tropical depression and rain on texas for 3 days like we had here in so fl last week shame it wont happen
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Quoting Fishaholic25fl:
So with pre-sean moving faster west........... Anyone think sean will push rina more north and then curve more into florida???????

nope I think Rena will recurve and be between Grand Cayman and the Isles of Youth then move ENE-E moving over North-Central Cuba because of this it will drag 97L(PRE-Sean) WNW-NW bringing it over Cayman Islands then to the Isles of Youth
Member Since: June 13, 2009 Posts: 2 Comments: 10852
Quoting Gorty:


Southern New England also but eastern New England as per the latest GFS will get hit the hardest (Eastern MA and RI are included).


Then it looks like the models are trending for an amplified trough again like on Saturday...Finally!!!
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Quoting Fishaholic25fl:
So with pre-sean moving faster west........... Anyone think sean will push rina more north and then curve more into florida???????
That is a great question! (wish I had the answer.. Taz? Levi?gulp...Reed?)
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HOT TOWERS NARRATED VIDEO

Link
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I do....and not wish casting - if the cooler water behind rina doesn't slow down development to much
Quoting Fishaholic25fl:
So with pre-sean moving faster west........... Anyone think sean will push rina more north and then curve more into florida???????


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Quoting ProgressivePulse:
One of the last couple visible shots of Rina. Definitely priming for an active night, outflow appears to be stellar ATM.


Yeah, you can see the "spiky" (for a lack of a better word) outflow, indicative of a quickly strengthening system.
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We that have been looking at Tropics for a while and some of us a long time KNOW it is very hard and difficult to forecast the Shear in an area 24-36hours out little lone 5 days or so out....Yes the models can give us a good hint of what might happen but, Shear is very difficult to see beyond 36hours....I would have thought the shear the models are seeing is from a strong front moving toward Florida about Friday or Saturday. But, this front seems to be getting weaker in every update. This weak front might not cause as much Shear for RINA so with that one could conclude a stronger system moving out into the GOM possibly.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Can anyone tell me how to put a profile picture on here? I've tried three times, and it hasn't worked.

Thanks in advance.
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Quoting Sfloridacat5:


And they are forecast to be reasonably close in 96 hours. But by then Rina could be in the process of being ripped apart by shear in the Southern GOM?

I think Rena is going to help 97L to develop fast I think maybe rapid development could be factored as well
Member Since: June 13, 2009 Posts: 2 Comments: 10852
Quoting ProgressivePulse:
One of the last couple visible shots of Rina. Definitely priming for an active night, outflow appears to be stellar ATM.



Now that my friends is the textbook definition of a CDO (Central Dense Overcast). Hurricane Rina impressing as the sun sets.
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So with pre-sean moving faster west........... Anyone think sean will push rina more north and then curve more into florida???????
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One of the last couple visible shots of Rina. Definitely priming for an active night, outflow appears to be stellar ATM.

Member Since: August 19, 2005 Posts: 5 Comments: 5020
I miss the pace of this blog when Hurricane Irene was striking my country. I don't miss Hurricane Irene, however.
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Quoting Dakster:


I feel a video link coming on... Someone always seems to post a hot towers video when those words are mentioned.


aka Patrap. ;-)
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Quoting Dakster:
Anyone else feeling like the NHC is gonna change the official forecast track at the next update?

yes I think tey will I say further S and E by the end of the track rena should be between Grand Cayman and the Isles of youth near 20.5N 82W movement to the ENE-E
Member Since: June 13, 2009 Posts: 2 Comments: 10852
Quoting Jaevyn:
Five hot towers on Rina last time I checked, definately the sign of a rapidly strengthening hurricane.


I feel a video link coming on... Someone always seems to post a hot towers video when those words are mentioned.
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Quoting KoritheMan:


You are forgiven because you like Pokemon.
And I like Sonic.
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Five hot towers on Rina last time I checked, definately the sign of a rapidly strengthening hurricane.
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Quoting wunderkidcayman:

true but 97L is moving much faster than Rina


And they are forecast to be reasonably close in 96 hours. But by then Rina could be in the process of being ripped apart by shear in the Southern GOM?
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Anyone else feeling like the NHC is gonna change the official forecast track at the next update?
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Definitely a front forecast to go through Florida around Friday.
Not the strongest of fronts, but an increased chance of rain with its passage and a slight drop in temperature (a few degrees off the high and low). The main difference will be a reinforcing shot of dry air and northerly breeze.

But we will have to watch the tropics. I'm not sure what effect Hurricane Rina might have on this forecast.
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Quoting CosmicEvents:
200 posts in 2 hours during primetime(for this blog) with a cyclone that's forecast to intensify and possibly hit some area within the prime demographic? pffft....we did that in 10-20 minutes in years past. That's some lull. Must ne a like a lull-22.


I cannot compute.
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Quoting KoritheMan:


You are forgiven because you like Pokemon.

LOL.
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Quoting TampaSpin:
I would guess the Rina and 97L is about 1500 miles apart at least.

true but 97L is moving much faster than Rina
Member Since: June 13, 2009 Posts: 2 Comments: 10852
200 posts in 2 hours during primetime(for this blog) with a cyclone that's forecast to intensify and possibly hit some area within the prime demographic? pffft....we did that in 10-20 minutes in years past. That's some lull. Must ne a like a lull-22.
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From last blog...
Quoting BahaHurican:
Evening all.
Ayup. It's been raining up town since after 1:30.... I actually got online to see where this unexpected rain is coming from, only to discover that Rina had been upgraded to hurricane status...

Not convinced yet that S FL and NW Bahamas is completely out of Rina's reach, but I guess we shall see....
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I would guess the Rina and 97L is about 1500 miles apart at least.
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Quoting Articuno:

XD It's ok.


You are forgiven because you like Pokemon.
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Quoting KoritheMan:


Hyperbole = exaggerating. I am saying you are exaggerating, greatly, by claiming the two are "thousands of miles apart". I doubt the distance is greater than 500 miles at this point.

Just messing with you though.

XD It's ok.
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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?


Six dropsondes from the Recon mission went into the 18Z GFS.


Link
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Quoting Articuno:

Huh?
Sorry I am only a teen.


Hyperbole = exaggerating. I am saying you are exaggerating, greatly, by claiming the two are "thousands of miles apart". I doubt the distance is greater than 500 miles at this point.

Just messing with you though.
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Quoting scott39:
When is the front forecasted to dip that far S and pull Rina to the N and then NE?






I am really confused with this one.....there was suppose to be a weak cold front move into Florida about Friday or Saturday but, when you look at the Temperature forecast for Tampa, the NWS in Tampa is not showing much of a cold front.....


Below is the 8am temp forecast starting on Friday thru Sunday.







Below is from WU for Tampa.......

Friday, 28

85 | 65 °F
Chance of T-storms
Chance of
Precipitation40%
Saturday, 29

81 | 58 °F
Partly Cloudy
Chance of
Precipitation10%
Sunday, 30

81 | 61 °F
Partly Cloudy
Chance of
Precipitation
Member Since: September 2, 2007 Posts: 178 Comments: 20439
...
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so glad to see a hurricane, after 2 days of naysayers and downcasters trashing it, had some model support saying it could rapidly intensify and it did. being a meterologist must be the only job where you can be wrong quite often and still not get fired!   good day to all.
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Quoting KoritheMan:


Now that's hyperbole, folks. :P


LOL
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Well, it's like I was saying yesterday... Rina's possibilities were pretty extensive. I'm not surprised to see RI today, and wouldn't be surprised to see it hold onto hurricane status after it crosses over or just west of Cuba [not for long, mind you]. The interesting points:

1) how much more deepening will we'll see
2) how much larger Rina will get
3) how quickly / extensively the front will impact our now possibly major hurricane.

Looks like an interesting week coming up.
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Quoting Ameister12:

Well there's not much more to talk about. When we get new info on Rina, than it will ramp back up, but the blog is still pretty active.

Ok. Still getting used to this.
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Quoting KoritheMan:


I am pretty sure only the 0z runs will have the recon data incorporated.


Ok then that makes sense, because I noticed the GFS initialized it at 1008 mb. Thank you
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Quoting Articuno:

Highly unlikely, they are thousands of miles ahead of eachother.


Now that's hyperbole, folks. :P
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Quoting Articuno:
Where'd everybody go?

Well there's not much more to talk about. When we get new info on Rina, than it will ramp back up, but the blog is still pretty active right now.
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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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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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