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 chrisdscane:
does 18z come out an exactly 8 or alitle before?




the 18z is out if your talk about the gfs
Member Since: May 21, 2006 Posts: 5091 Comments: 114776
Deep convection all in her core, the eyewall will be complete very soon, and HOT TOWERS EVERYWHERE!!! lol, yikes
Link
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Rina is definitely going nowhere right now - maybe the slowest of northward drifts, but not west.
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Quoting cyclonekid:

That was in 1995. :)


Yeah, but a R hurricane too. All 4 have been hurricanes
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does 18z come out an exactly 8 or alitle before?
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Quoting TropicalAnalystwx13:

I know, lol...I knew there was a chance for rapid intensification into a strong hurricane, but I wasn't really expecting it!


I always expect RI in the NW Caribbean with 70% of the storms that come this way. The history is there.
Member Since: August 19, 2006 Posts: 0 Comments: 15776
Latest RGB imagery shows she's organizing and tightening all the deep convection into her core, she's ready for the real strengthening now... Uh oh
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Quoting TropicalAnalystwx13:
Look at 97L:


WHOA!! If that anticyclone moves with it, we could be talking about a serious system. Paloma situation maybe?
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Quoting floridaT:
if i remember right when wilma was parked in the nw carribean the tracks were all over then suddenly pointed at so fl and was there fast. i believe late season storms in this area with the fairly fast moving fronts are really difficult to forecast.
You don't remember right, or you weren't paying attention to the right people at the time. Here on this blog we used to have a few people who consistently outdid the NHC. These folks are still around on the net somewhere. Wilma was a much more definite forecast, so much so that when I bought a new car here in SFLA days before Wilma I closed the deal but asked the dealer to store the car at his place until after the storm hit. He said "what storm?" I picked my car up 3 weeks later, which was as soon as I could after he reopened.
Member Since: August 3, 2005 Posts: 10 Comments: 5535
anyone think 97L could be code orange at 8pm?
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Quoting Cotillion:


and Roxanne.

That was in 1995. :)
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Quoting cyclonekid:

There aren't any watches or warnings up, therefore no intermediate advisories.


then my bad we'll see if they issue one anyway
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One heck of a ULAC.. excellent ventilation. Lets see if it actually manages to use it.
Reminds me of preTomas sitting east of Trinidad as a tropical wave, then began its organization...
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Quoting kmanislander:


That's what I told you a couple of days ago, Cat 3 or 4. You said "wow" lol

I know, lol...I knew there was a chance for rapid intensification into a strong hurricane, but I wasn't really expecting it!
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Quoting chrisdscane:



umm there should be

There aren't any watches or warnings up, therefore no intermediate advisories.
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Quoting Seflhurricane:
there are no intermediate advisories



umm there should be
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97L may be one to worry about too

huge anti cylcone over the system and the latest tracks have it curving north towards western cuba in 5-6 days

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Cat 2 at 8PM EST.
JMO.
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Quoting chrisdscane:
rita still at 75 at 8 imo
there are no intermediate advisories
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Quoting TropicalAnalystwx13:

As soon as Rina closes her eyewall, which, according to satellite imagery, she is very close to doing, we may see her really take off in intensity.

I would not doubt a Category 4 hurricane at this point.


That's what I told you a couple of days ago, Cat 3 or 4. You said "wow" lol
Member Since: August 19, 2006 Posts: 0 Comments: 15776
Quoting CybrTeddy:


One heck of a ULAC.. excellent ventilation. Lets see if it actually manages to use it.

I have to say, if it tries to advantage of the super favorable conditions it has in front of it, we could be looking at an even bigger beautiful monster by the end of the week and into the weekend.
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rita still at 75 at 8 imo
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super intrested in the 18Z models
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Quoting TropicalAnalystwx13:
Look at 97L:



One heck of a ULAC.. excellent ventilation. Lets see if it actually manages to use it.
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Quoting TropicalAnalystwx13:
Look at 97L:


O_O
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Quoting HurricaneDean07:

2005~2011
Hurricane Rita
Hurricane Richard
Hurricane Rina


and Roxanne.
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Quoting TropicalAnalystwx13:
Look at 97L:


It's got a magical circle
yay
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Quoting Saltydogbwi1:


I remember Mitch well it sat off the coast of honduras as a Major for 5 days i think it was...over 11,000 lives lost directly related to the storm.

With Mitch I was just 3 but all my family says that is true that Mitch bring a lot of rains but they say Fifi was worse than him
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Quoting stormpetrol:


Hey bro, I just noticed that West Bay is kissing the cone!


LOL. I saw your post earlier about the NHC calling the WNW turn right after the HH found Rina basically meandering. The three fixes showed the second to the NE of the first and the third to the NW of the second and to the N of the first yet the motion was called to the WNW.

There was certainly no "motion" other than the meandering and the explanation that the NHC goes on 6 hourly fixes does not explain how the call for the WNW turn was made when it wasn't going anywhere but a net drift to the N.

I guess when the eye pops out we will know for sure where it's heading to lol.
Member Since: August 19, 2006 Posts: 0 Comments: 15776
Quoting Cotillion:
Yikes. Rina ate her Weetabix this morning.

What is it with R names and hurricanes?


2005~2011
Hurricane Rita
Hurricane Richard
Hurricane Rina
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Quoting BahaHurican:


NHC isn't forecasting it to become a major until Wednesday, but I think this system looks like one that could reach cat three by this time tomorrow afternoon. This is probably the best looking cat 1 hurricane this season.


I'm inclined to agree, the hot towers suggest that the storm is still undergoing rapid strengthening, I wouldn't be surprised to see a high level Cat 1 in the next advisory.
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Quoting TampaSpin:



theres the front but, it does not sound like its a big one tho...


I predict tomorrow to be a whole different ballpark. I can understand them pointing to that yesterday. But today, models have amplified the trough more.

I predict a sunny crisp and cool(after Friday's rains) Halloween Weekend with highs in the low 70's and lows in the low 50's(40's in rural areas).

I also predict the NHC to speed Rina northeastwards after Thurs.

The overal setup just doesn't support a stalled out or retrograding frontal boundary this weekend(The Bahama's is a different story).
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Quoting Tazmanian:
i new it i come home to a hurricane

I know I wasn't expecting this!
:|
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Look at 97L:

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I will give 97l 20%
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Quoting TampaSpin:
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.


I have noticed that as well, Tampa. And that could either cause the steering currents to collapse over the area, or cause a more gradual turn to the NE (which is why, other than this being a stronger storm than anticipated, many models latch onto a more gradual turn as opposed to the abrupt turn that the NHC is currently advertising).

Also of note, I was seeing some earlier temperature forecasts of low and mid 70s for highs, lows in the low to mid 50s for the weekend here, now have backed off and anticipating temps near 80 to low 80s and lows in the mid and upper 60s this weekend. So weaker front is advertised by the NWS office in Melbourne... lets see how this thing plays out now.
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Quoting FLWaterFront:


The NWS is now downplaying the strength of the front that is forecast to move through Florida at the end of this week. But that could well change in a couple of days.

A week or more ago, when the models were first hinting at a very strong cold front with record low temperatures following it, even local TV mets were mentioning this prospect in their broadcast reports. But now the models are depicting a weaker system with only "near normal" temperatures following behind.

I doubt that personally but it is only my take. So far this year, the pattern has been for fronts be stronger than usual with much colder air masses than normal, over the Southeastern US.

I would not doubt that Rina will eventually get pulled north by this upcoming trough and wind up in either the Florida Keys or SW FL but as a moderate Tropical Storm, not a hurricane.

Many have mentioned Wilma from 2005 and what she did but not many have mentioned Hurricane Mitch from 1998. That was located in a similar area in late October of that hurricane season. And a trough eventually picked Mitch up and moved him toward SW Florida but he arrived there as a moderate tropical storm and not a 'cane, which is why so few remember Mitch. The effect on Florida was negligible as well.


I remember Mitch well it sat off the coast of honduras as a Major for 5 days i think it was...over 11,000 lives lost directly related to the storm.
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Quoting yqt1001:
Newest microwave image.


As soon as Rina closes her eyewall, which, according to satellite imagery, she is very close to doing, we may see her really take off in intensity.

I would not doubt a Category 4 hurricane at this point.
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Thanks, awesome link is very informative!
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Quoting stormpetrol:


Hey bro, I just noticed that West Bay is kissing the cone!

hey dude yeah I know but I think the plots and Cone will move further south and I think the recure will be a sharper turn than whats in the cone now plus I think it will pull N earler that forecasted and further E bringing it in between us and the Isles of youth N or S a few degrees but hey look at 97L(PRE-SEAN) forecasted to be right on top of us by Fri as Cat3/4
Member Since: June 13, 2009 Posts: 2 Comments: 11215


Still embedded within the Trough from the Cold Front....as long as it stays there Rina is not being affected by much dry air. Still got a weak trough into very South Florida as seen on WV
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Damn Rina is just sitting there spinning, getting more powerful by the hour!
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321. Gorty
Quoting BahaHurican:
I gotta agree this look is always ever so much more attractive around 45W 35N.... lol... and recurving to the N and NE....





For what system?
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Quoting TampaSpin:

Well, at least they agree on making it a moderate/strong Category 2. then most shoot up to Category 3, and of coarse the doomcasting GFDL showing a category 4/5
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Yikes. Rina ate her Weetabix this morning.

What is it with R names and hurricanes?

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Quoting TropicalAnalystwx13:

Yeah, and I don't like the ''look''.
I gotta agree this look is always ever so much more attractive around 45W 35N.... lol... and recurving to the N and NE....



Member Since: October 25, 2005 Posts: 19 Comments: 21592
Quoting FLWeatherFreak91:
.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.


The NWS is now downplaying the strength of the front that is forecast to move through Florida at the end of this week. But that could well change in a couple of days.

A week or more ago, when the models were first hinting at a very strong cold front with record low temperatures following it, even local TV mets were mentioning this prospect in their broadcast reports. But now the models are depicting a weaker system with only "near normal" temperatures following behind.

I doubt that personally but it is only my take. So far this year, the pattern has been for fronts be stronger than usual with much colder air masses than normal, over the Southeastern US.

I would not doubt that Rina will eventually get pulled north by this upcoming trough and wind up in either the Florida Keys or SW FL but as a moderate Tropical Storm, not a hurricane.

Many have mentioned Wilma from 2005 and what she did but not many have mentioned Hurricane Mitch from 1998. That was located in a similar area in late October of that hurricane season. And a trough eventually picked Mitch up and moved him toward SW Florida but he arrived there as a moderate tropical storm and not a 'cane, which is why so few remember Mitch. The effect on Florida was negligible as well.
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some1 link the 8pm models please
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Quoting TampaSpin:


All models indicate conditions are conductive for further intensification during the next 48 hours.
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Newest microwave image.

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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.