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 TropicalAnalystwx13:

Whats YOUR opinion on the Invest Levi, especially given that all the models bring it to hurricane status and further up to major hurricane status?


You mean the statistical guidance suggests that conditions ahead of it are favorable, and that's all they are telling you. I don't see the GFDL and HWRF or any other dynamic intensity models being run on it.

The statistical models are right that conditions ahead are favorable, and it should be watched, but as some have said, don't expect much until it's nearing Jamaica's longitude or farther west. It may find a sweet spot if we have a strong Hurricane Rina off the NE Yucatan in 3-4 days, similar to the chain formation that Cape Verde systems form, in which each system supports another.
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Quoting Tazmanian:




there is no hurricane watch up so you wont see the next update in tell 11pm


right!, I forgot the watches were discontinued
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No watches, no intermediate advisory. Next advisory is 11PM EDT.

WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN BELIZE...THE EAST COAST OF THE YUCATAN PENINSULA...
AND THE ADJACENT ISLANDS SHOULD MONITOR THE PROGRESS OF RINA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.
Member Since: July 6, 2010 Posts: 113 Comments: 31452
Quoting trHUrrIXC5MMX:
Its 808 PM and no update...




there is no hurricane watch up so you wont see the next update in tell 11pm
Member Since: May 21, 2006 Posts: 5091 Comments: 114717
Rina should be a Category 2 at 11 pm advisory. she's really impressing me right now, and she'll have 3 more hours to close off her eyewall, and with all the deep convection she's popping it won't be hard for to intensify. should see Category 3 tomorrow morning and a 4 tomorrow night/early wednesday morning
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Well with the upper winds looking like this in 72 hours, I would be worried about 97L too.

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Quoting TampaSpin:


PLENTY OF HEAT ALL THE WAY TO FLORIDA

The only things really stopping Rina from hitting Florida as a hurricane are dry air and wind shear...But a combination like that is deadly to tropical cyclones.
Member Since: July 6, 2010 Posts: 113 Comments: 31452
hello! it's been a while.. this baby is looking great. hey taz
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Quoting Levi32:


The flow over top of it is predominantly easterly. Granted, though, they are not much different than the winds over Rina in terms of overall favorability.

levi is a landfall in florida as a cat 1 still a possibility?
Member Since: August 23, 2011 Posts: 0 Comments: 1292
Its 808 PM and no update...
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PLENTY OF HEAT ALL THE WAY TO FLORIDA
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting Levi32:


The flow over top of it is predominantly easterly.


Whats YOUR opinion on the Invest Levi, especially given that all the models bring it to hurricane status and further up to major hurricane status?
Member Since: July 6, 2010 Posts: 113 Comments: 31452
am back too lurk mode
Member Since: May 21, 2006 Posts: 5091 Comments: 114717
451. j2008
I'll be back later. Keep an eye on Rina, dont want her pulling someting on us.....
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oh that's right, intermediate gone, Honduras dropped their TS watches.
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That little circle near 76W has higher TCHP values and water depth/temperature than what Rina is expected to pass over tonight and tomorrow...Lets hope it is not a tropical cyclone by then.



Member Since: July 6, 2010 Posts: 113 Comments: 31452
Quoting Hurricanes101:
ok question, how can upper level winds be marginally favorable for development with that monster anti-cyclone over it.


The flow over top of it is predominantly easterly.

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The sharp right turn is not as sharp anymore it seems.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting kmanislander:


It was meandering earlier with a net Northerly drift. Looks to still be doing the same or stalled IMO.


I agree looks stationary or drifting very slightly north very impressive CDO
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lol, everyone stalking the NHC site, waiting for intermediate advisory, we will see everyone pop up in the matter of a sec
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443. Gorty
Why did they stop doing intermediate advisories on Rina?
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Quoting kmanislander:


Do you really want to know ? lol

Just kidding.

If 97L becomes a TD by the time it reaches 75 to 80 W we will likely see another major hurricane from that system. Different track and no cold water wake from Rina to contend with.

Wow.
XD
Member Since: July 6, 2010 Posts: 113 Comments: 31452
Quoting WoodyFL:


No, even if it were to come to S FL, It is unlikely to be very strong. I wouldn't worry just yet. The waters are much cooler near Florida than in 2005. The shear is also expected to be high.


I wouldn't expect it to be strong either. I'm getting ready for a strong TS/ Cat. 1 just in case.

PS, you have mail.
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Quoting WoodyFL:


No, even if it were to come to S FL, It is unlikely to be very strong. I wouldn't worry just yet. The waters are much cooler near Florida than in 2005. The shear is also expected to be high.


high shear for a storm moving northest in this situation may not be as detrimental to the storm

that being said, the chances of it staying a powerful hurricane as it makes it potential approach to Florida is low, but there are many factors to that

How strong does she get now?

Does she actually make landfall in the Yucatan like forecast?

Is the GFS right and the system meanders around the NW Caribbean in a few days?

Those are questions that will be answered in the next few days
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Quoting TropicalAnalystwx13:
So, Kman, you've nailed Rina's intensity since several days ago...What do you think of 97L?


Do you really want to know ? lol

Just kidding.

If 97L becomes a TD by the time it reaches 75 to 80 W we will likely see another major hurricane from that system. Different track and no cold water wake from Rina to contend with.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Quoting Tazmanian:




me annoying? nevere am a good little boy you nevere see me in the paper


Taz, just stop the blog police thing. It's gotten really annoying and out of hand. You poof people for nothing and you yell at people for nothing. It's time to drop the act.
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I have been shocked the last three times I have been on here. Yesterday shocked that there was a couple of invests, today shocked that we have a named storm, and now shocked that we have a hurricane.

Wonder if Rina will cancel the kiddies Halloween plans in sw florida? What say you, weather guru's?

Thanks
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Quoting Seflhurricane:
have the models changed in the 18Z model run


The 18Z models do have a little more poleward bias to them this cycle. The 00Z models should really be more useful, as it now has data in there from the HH earlier with a good center fix and intensity. Should hopefully see more resolve in the models coming out shortly.
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Quoting GeoffreyWPB:


Thanks Woody...Good call last night. You nailed it!


Aw shucks. Was just a good guess is all.
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Quoting ClaySFL:


What do you think Woody? Bad news for us?


No, even if it were to come to S FL, It is unlikely to be very strong. I wouldn't worry just yet. The waters are much cooler near Florida than in 2005. The shear is also expected to be high.
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So, Kman, you've nailed Rina's intensity since several days ago...What do you think of 97L?
Member Since: July 6, 2010 Posts: 113 Comments: 31452
if Rina aims at key west by Saturday bad news. this week is there biggest week of the year.
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Quoting Hurricanes101:
ok question, how can upper level winds be marginally favorable for development with that monster anti-cyclone over it.

It can't, lol.

The NHC probably has more tools not available to us though. Maybe they see something we can't?
Member Since: July 6, 2010 Posts: 113 Comments: 31452
yep they upped the precentage not as much as expected but still they upped it maybe at the 1 am two they may up it to that
Member Since: June 13, 2009 Posts: 2 Comments: 11004
Quoting wunderkidcayman:

nope it moving N and growing in size and if the N movement continues through 12/1am boy I tell u we are in for more than what we already have just imagen if it just started to stall NEward although seem unlikley but anyway I am more worried about 97L boy Cat3/4 on to of us hmm


It was meandering earlier with a net Northerly drift. Looks to still be doing the same or stalled IMO.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
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 agree we won't see highs in the 50's and 60's like they were showing a week ago(the models that is). But for the NWS to keep temps in the low 80's is a bit much. Highs in the Low-mid 70's, lows in the low-mid 50's with dewpoints in the 30's seems more reasonable.
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Quoting WoodyFL:
Good link. Thanks Geoff!. Looks stronger than a 1.


Link


Thanks Woody...Good call last night. You nailed it!
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weather channel agrees with current nhc track
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Outflow is looking healthier to the South of Rina!
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ok question, how can upper level winds be marginally favorable for development with that monster anti-cyclone over it.
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TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON OCT 24 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED HURRICANE RINA...LOCATED ABOUT 195 MILES SOUTHWEST OF
GRAND CAYMAN.

A BROAD LOW PRESSURE SYSTEM LOCATED ABOUT 100 MILES NORTH OF
MARGARITA ISLAND VENEZUELA IS PRODUCING WIDESPREAD CLOUDINESS AND
SCATTERED THUNDERSTORMS OVER MUCH OF THE SOUTHEASTERN CARIBBEAN SEA
AND ADJACENT LAND AREAS. UPPER-LEVEL WINDS ARE ONLY MARGINALLY
CONDUCIVE FOR DEVELOPMENT AT THIS TIME...BUT THEY COULD BECOME
SOMEWHAT MORE FAVORABLE IN A COUPLE OF DAYS WHEN THE LARGE
DISTURBANCE MOVES INTO THE CENTRAL CARIBBEAN SEA. THIS SYSTEM HAS A
LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 MPH.
REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND GUSTY WINDS
ARE EXPECTED ACROSS ARUBA...BONAIRE...AND CURACAO THROUGH TONIGHT.
FOR ADDITIONAL INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE
STATEMENTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER STEWART
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Quoting kmanislander:


I hope they are looking at a system sitting still for the next advisory.


nope it moving N and growing in size and if the N movement continues through 12/1am boy I tell u we are in for more than what we already have just imagen if it just started to stall NEward although seem unlikley but anyway I am more worried about 97L boy Cat3/4 on to of us hmm
Member Since: June 13, 2009 Posts: 2 Comments: 11004
have the models changed in the 18Z model run
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Quoting WoodyFL:
Good link. Thanks Geoff!. Looks stronger than a 1.


Link


What do you think Woody? Bad news for us?
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419. j2008
Darn I'm too slow.....20% I was right.
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Quoting kmanislander:


You know the rule right ?. No action from this until after 75W.

I'll say 70W.
Member Since: July 6, 2010 Posts: 113 Comments: 31452
Quoting Saltydogbwi1:


pretty calm in spotts right now where on island are you Kman?


South Sound, that's why we share the same weather :-)
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Quoting TropicalAnalystwx13:
20% it is.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON OCT 24 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED HURRICANE RINA...LOCATED ABOUT 195 MILES SOUTHWEST OF
GRAND CAYMAN.

A BROAD LOW PRESSURE SYSTEM LOCATED ABOUT 100 MILES NORTH OF
MARGARITA ISLAND VENEZUELA IS PRODUCING WIDESPREAD CLOUDINESS AND
SCATTERED THUNDERSTORMS OVER MUCH OF THE SOUTHEASTERN CARIBBEAN SEA
AND ADJACENT LAND AREAS. UPPER-LEVEL WINDS ARE ONLY MARGINALLY
CONDUCIVE FOR DEVELOPMENT AT THIS TIME...BUT THEY COULD BECOME
SOMEWHAT MORE FAVORABLE IN A COUPLE OF DAYS WHEN THE LARGE
DISTURBANCE MOVES INTO THE CENTRAL CARIBBEAN SEA. THIS SYSTEM HAS A
LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 MPH.
REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND GUSTY WINDS
ARE EXPECTED ACROSS ARUBA...BONAIRE...AND CURACAO THROUGH TONIGHT.
FOR ADDITIONAL INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE
STATEMENTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER STEWART




for the 1st time in days its up too 20%
Member Since: May 21, 2006 Posts: 5091 Comments: 114717
414. j2008
Quoting Hurricanes101:
anyone want to venture a guess at the percentages for 97L at 8pm?

I may be inclined to go 30%
Afternoon everyone. I see Rina has unleashed the wrath, I think we will see her at 85-90 at next update. 97L will probably be at 20-30%, TD by tommorow night at soonest. So any ideas?
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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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