Rina still a Cat 2, and may have peaked in intensity

By: Dr. Jeff Masters , 1:48 PM GMT on October 26, 2011

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There is little change to Category 2 Hurricane Rina, which continues slowly west-northwest at 4 mph towards Mexico's Yucatan Peninsula. The most recent hurricane hunter mission was at 3:58 am EDT this morning, and the next aircraft is not due into the storm until this afternoon, so we'll have to rely on satellite estimates of the storm's strength until then. Recent satellite intensity estimates suggest Rina has peaked in intensity, and may have weakened slightly since the last hurricane hunter mission. The eye is no longer visible on visible satellite loops, and the storm has a distinctly lopsided appearance, which are both signs that Rina may be weakening. Recent microwave images (Figure 1) suggest that the southern portion of Rina's eyewall may have a gap in it. Wind shear is a moderate 10 - 20 knots due to upper-level winds out of the south. Water temperatures are very warm, 29 - 30°C, but Rina will be leaving a region of high oceanic heat content late tonight, and will not have as much high-energy fuel to sustain itself. Rina has brought sporadic heavy rain squalls to the Yucatan; Cozumel Island airport reported 9.10" of rain yesterday and another 3.25" as of 9 am EDT today. I'm not sure this is correct, since two personal weather stations on the island reported only 1 - 2" of rain over the past two days. The outer rain bands of Rina are visible on Cancun radar and the La Bajada, Cuba radar.

If Rina does make it to Category 3 strength, it would join a very short list of major hurricanes that have occurred this late in the year. Since record keeping began in 1851, there have been only twelve major hurricanes in Atlantic on October 26 or later. Rina is a medium-small hurricane, with hurricane-force winds that extend out 25 miles from the center. The latest estimates of Rina's Integrated Kinetic Energy (IKE) made yesterday afternoon by NOAA's Hurricane Research Division put the damage potential of Rina's storm surge at 2.5 on a scale of one to six. This is a relatively low number for a Category 2 hurricane, and means that storm surge damage will be confined to a relatively small area in the right front quadrant of Rina's eyewall. For comparison, the storm surge damage potential for Hurricane Irene when it was a strong tropical storm approaching Long Island, New York on August 28, 2011 was 4.1 on a scale of 1 to 6, since Irene was a huge storm that put vast areas of the ocean into motion.


Figure 1. Microwave satellite image of Hurricane Rina taken at 7:15 am EDT October 26, 2011. Rina appears to only have the northern half of its eyewall intact. Image credit: Navy Research Lab, Monterey.

Forecast for Rina
The hurricane hunters found that Rina had a large elliptical eye with a diameter of 23 - 34 miles with a gap in the south eyewall during their 3:58 am EDT eye penetration this morning. Rapid intensification usually requires a circular eye with no gap in it, and thus I expect only gradual intensification of Rina can occur today. Wind shear is not expected to increase to the high range until Thursday afternoon, so Rina still has a day and a half to potentially intensify. Given the storm's inability to close off its eyewall so far, I expect that a Category 3 storm is the strongest that we will see. It is more likely that Rina has peaked in strength, and will begin to weaken. On Thursday, Rina will encounter high wind shear associated with upper-level westerly winds associated with the jet stream and a trough of low pressure moving through the Gulf of Mexico. These conditions should weaken the hurricane, and turn Rina more to the northwest by Thursday and northeast on Friday. Cozumel Island off the coast of Mexico's Yucatan Peninsula appears at the highest risk of receiving a direct hit from Rina; the 5 am EDT Wind Probability Forecast from NHC gave the island a 27% chance of receiving hurricane force winds, the highest chance of any land area in the forecast. If Rina hits Mexico, it would most likely be at Category 1 strength, with Category 2 strength also quite possible. NHC is giving Rina a 21% chance of being a Category 3 or stronger hurricane on Thursday afternoon, and I don't expect the storm will be a major hurricane at landfall. The chief threat from Rina is probably its rains; the hurricane is moving slowly and has the capability of dumping 8 - 16 inches of rain over the coastal Yucatan. Western Cuba is also at risk of receiving heavy rains of 5 - 10 inches.

After Rina makes its closest pass by Cozumel, it is uncertain if the storm will be strong enough to fully "feel" the steering influence of the trough, and be swept to the east-northeast into Southwest Florida and the Florida Keys. If Rina makes landfall in the Yucatan Peninsula and weakens significantly, the storm will likely be too weak to get caught up by the trough and will remain trapped in the Western Caribbean. This is the solution of the latest runs of the ECMWF and HWRF models, with the usually reliable ECMWF model continuing to predict that Rina will dissipate over the Yucatan. However, if Rina grazes the Yucatan and remains strong through Friday, it is more likely to get caught up by the trough and drawn into the Florida Keys or Southwest Florida near Marco Island, as a weakening tropical storm. This is the solution of the latest 2 am EDT run of the GFDL model. The latest 2 am EDT runs of the GFS and NOGAPS models are in-between, predicting that Rina will get very close to the Keys on Saturday, but then weaken and sink southwards towards Cuba. There is high degree of uncertainty which set of model runs will be correct, and the threat to Florida depends strongly upon how much of a blow Mexico receives from the hurricane.

97L in the Central Caribbean not expected to develop
A broad region of low pressure in the Central Caribbean south of Haiti and the Dominican Republic, (Invest 97L), is moving west at 10 - 15 mph. Heavy thunderstorm activity has decreased since yesterday, and is disorganized. The storm is surrounded by a large region of dry air, and this dry air is the main impediment to development. Wind shear is a low 5 - 10 knots, and is expected to remain low through Thursday. None of the reliable models are predicting that 97L will develop, and NHC gave 97L just a 10% chance of developing into a tropical depression by Friday, in their 8 am EDT Tropical Weather Outlook. NHC is no longer interested enough in 97L to generate computer model forecasts of its track. Heavy rains from 97L should reach Jamaica on Thursday, and the Cayman Islands by early Friday morning.

There will be a new post on Rina late this afternoon.

Jeff Masters

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Rina is close to the Yucatan peninsula. :-o
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Watching these late season storms is like watching the NFL post-season. Hostile weather conditions (for many outside games)and lot's of hope but very few make it to the Superbowl............ :)
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If she looks good on visable now, she must have looked real awful at noon.

The core of the storm is impressive, the rest of it is a raggedy piece of garbage. Right now it looks like Super Thunderstorm Rina more than a hurricane.

It is picking up the pace though so it should be able to reconstruct itself a bit.
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Quoting cchsweatherman:


Your images are not appearing.


Tryin to fix that. don't know what's wrong.
Member Since: September 2, 2008 Posts: 0 Comments: 744
Quoting alvarig1263:
It appears as if Rina is not only redeveloping her inner core, but is amplifying the convection in all quadrants except for southwest around her. Compare the two satellite images about 4 hours apart. One from a little past 12PM and the most recent satellite image.

4 Hours Ago:


Now @ 4PM:


It seems that she has bolstered the convection and is using the moisture from 97L nicely to enlarge herself and build a "shield" of convection on her eastern side. Definitely something to watch to see if this trend continues. You can also tell that her edges are not fanning as much, so wind shear must be lower than it has been for the time being and she's making the best use of that time. We'll have to see what recon finds because it appears she's not giving up yet. Wouldn't be surprised to see an eye within 2-6 hours.


Your images are not appearing.
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It appears as if Rina is not only redeveloping her inner core, but is amplifying the convection in all quadrants except for southwest around her. Compare the two satellite images about 4 hours apart. One from a little past 12PM and the most recent satellite image.

4 Hours Ago:


Now @ 4PM:


It seems that she has bolstered the convection and is using the moisture from 97L nicely to enlarge herself and build a "shield" of convection on her eastern side. Definitely something to watch to see if this trend continues. You can also tell that her edges are not fanning as much, so wind shear must be lower than it has been for the time being and she's making the best use of that time. We'll have to see what recon finds because it appears she's not giving up yet. Wouldn't be surprised to see an eye within 2-6 hours.
Member Since: September 2, 2008 Posts: 0 Comments: 744
Pre 98L in the CATL looks interesting indeed. Still need some rains, what a quite october for us in the Lesser Antilles, strange..
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Just looking at the latest satellite trends, I would expect Hurricane Rina to restrengthen possibly back to Category 2 status within the next 24 hours before the environment becomes less favorable for the storm. Noticing spiral banding pattern returning to the storm with a new spiral band forming over the Yucatan. In addition, core convection continues to deepen over the past few hours and the environment has become more moist throughout the day.
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456. 996tt
Quoting barotropic:


Nothing really to prepare for.....if anything, keys marine interests may take note. If anything, gusty winds 30 - 35 mph, rough water and slightly higher tide. Looks like a pretty much non event either way. This storm hardly has a shot in hell to make it to Fla as anything but a slight pain in the neck.....


Haha, just give us some swell. Don't need the storm. It can die out and not cause destruction provided it gets serious and pumps some nice swell up this way before sheer tears it a part.

Been saying since Lee only two scenarios existed in GOM for remainder if this hurricane season: (1) storms meandering West at or near Yucitan Penisula, continuing West and staying well below Texas border (which we have seen); and (2) a close to Wilma track with a Yucitan hit or swipe but storm staying at or below Florida straights and hugging Cuba.

So far, I have been better than models. Lee interacted with front and caused a powerful deep front that ended the GOM hurricane season early. Said that before Lee had completely made it through. I open to payment if large sums for which I would agree to replace the schizophrenic models.

Was surprised no mets or anyone else saying except kook on here which jumped on my theory and stated it over and over in the two weeks following Lee. Just in years past, I have heard mets state similar troughs spelled end if cane season for GOM. This Ine was just much earlier than in previous years. We can thank Lee for shutting down the GOM this year.
Member Since: September 5, 2008 Posts: 0 Comments: 308
Quoting reedzone:


Levi doesn't believe it will effect Rina, it's not a strong fetch of dry air.. Shouldn't affect her much.
Actually I think he's noticing the moisture and spin with ex-97L.
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Current Steering Layer

Member Since: October 19, 2011 Posts: 0 Comments: 101
Some of the GFS ensemble members have trended farther north.

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Quoting BenBIogger:


See that small tongue of dry air SE/E of Rina? Now watch what happens in 3-4 hours from now.


Levi doesn't believe it will effect Rina, it's not a strong fetch of dry air.. Shouldn't affect her much.
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Quoting GTcooliebai:
Nice little ULL in the North Atlantic spinning away.


See that small tongue of dry air SE/E of Rina? Now watch what happens in 3-4 hours from now.
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Shortwave IR...zoom in on the center

Link
Member Since: October 19, 2011 Posts: 0 Comments: 101
whats the Euro say?
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Quoting BenBIogger:
Nice little ULL in the North Atlantic spinning away.
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My point when I said colder cloud tops doesn't mean its strengthening was that Rina has been firing up cold cloud tops all day and all of last night. Cold, then they warm, then cold. This goes on while intensification is going on and even some during weakening. Its what happens in cyclones.
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Member Since: October 19, 2011 Posts: 0 Comments: 101
Quoting barotropic:


Colder cloud tops around center doesn't mean its strengthening
It was actually a ring developing around the CDO which typically indicates strengthening, but that is only in an environment around it conducive for development, right now its trying to fight off dry air.
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Looks like the Euro is much more amplified with the trough so I expect the NHC to speed this thing ENE.
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Quoting alvarig1263:


Well the latest Vortex Message indicates an eye wall has redeveloped so with the presence of an actual eye maybe they'll hit the center better this time.
I do believe that Rina will strengthen considerably the next 12 to 24 hours. Has a few things going its way now that it is moving.
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Quoting barotropic:


Colder cloud tops around center doesn't mean its strengthening


...
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Quoting stormwatcherCI:
I know everyone is focused on Rina but just 3 hours ago 97L had no vorticty at the 850 mb level but now is displaying very good and concentric vorticity. Maybe the development process has begun now.






All season, just when you think they are gone...they come back to life! Sigh! Been a LONG, strange, confusing season. Not over yet. Sigh (again). Rina is such a little scrapper, I am rooting for her even though I live in S. FL. LOL

And welcome Woody. Not on my iggy list either. Thanks for all your insightful observations and opinions.
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439. 7544
rina now has that hurricane symbol look to her
thanks woody keep up the good work
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Quoting GTcooliebai:
Are you sure it is not just maintaining its strength, I thought the same thing last night, and it ended up weakening?


Colder cloud tops around center doesn't mean its strengthening
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Interesting features in the Atlantic...

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Quoting WoodyFL:
Looks like 97L wants to flare-up again.

It's dark over there in the GOM, did it turn night over there already? :-P
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Quoting stormwatcherCI:
I know everyone is focused on Rina but just 3 hours ago 97L had no vorticty at the 850 mb level but now is displaying very good and concentric vorticity. Maybe the development process has begun now.






Whoops, sorry storm, we must have been posting at the same time. I didn't see this when I posted my image about ex-97L.
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Quoting ProgressivePulse:
403. Buhdog 7:22 PM GMT on October 26, 2011

419. barotropic 7:33 PM GMT on October 26, 2011




Just a little humor to lighten the, what seemed to be, increasingly edgy mood in here. Hopefully all saw it that way... :-)



i dont think he got it..

i sure did. I LoL'd
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Quoting GTcooliebai:
I wouldn't call it a non-event just yet, certainly nothing you have to prepare for I agree with that, but like I said earlier I'm interested to see what will happen with the interaction between the front and what is left of Rina, probably round 2 of Severe Weather in South FL. similar to 95L.


Well , dont mean non event for precip or severe weather issue. I am saying IMO...only....this will not be a tropical event...as in watches , warnings etc. in florida.
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Quoting stormwatcherCI:
I know everyone is focused on Rina but just 3 hours ago 97L had no vorticty at the 850 mb level but now is displaying very good and concentric vorticity. Maybe the development process has begun now.




I'm not seeing much on satellite now, but with Rina weakening and pulling away ever so slowly, there is a chance 97L makes a comeback.
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Funktop loop
Link
Member Since: October 19, 2011 Posts: 0 Comments: 101
H.Rina's_6pmGMT_ATCF : Starting 25Oct_6pmGMT and ending 26Oct_6pmGMT

The 4 eastern line-segments represent HurricaneRina's path,
the westernmost line-segment is the straightline projection for 26Oct_6pmGMT,
the coastline dumbbell at 19.168n87.543w-SJX is the endpoint of the 26Oct_12pmGMT
straightline projection connected to its nearest airport,
and the coastline dumbbell at 18.187n87.849w-SPR is the same for 26Oct_6amGMT.

Using straightline projection of the travel-speed&heading derived from the
ATCF coordinates spanning the 6hours between 12pmGMT then 6pmGMT :
H.Rina's travel-speed was 5.5mph(8.9k/h) on a heading of 308.1degrees(NW)
H.Rina was headed toward passage over Herrero,QuintanaRoo,Mexico ~1day1hour from now

Copy&paste mhic, 18.187n87.849w-spr, 19.168n87.543w-sjx, 17.3n84.3w-17.4n84.6w, 17.4n84.6w-17.5n85.0w, 17.5n85.0w-17.7n85.3w, 17.7n85.3w-18.0n85.7w, 17.7n85.3w-19.295n87.462w, tuy into the GreatCircleMapper for more info

The previous mapping for 26Oct_12pmGMT
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Looks like 97L wants to flare-up again.

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403. Buhdog 7:22 PM GMT on October 26, 2011

419. barotropic 7:33 PM GMT on October 26, 2011




Just a little humor to lighten the, what seemed to be, increasingly edgy mood in here. Hopefully all saw it that way... :-)

Member Since: August 19, 2005 Posts: 5 Comments: 5452
Quoting Skyepony:


And again it is fairly small. These eye drops too with the kinda higher winds & much higher pressure than extrapolated.. that was two in a row & same pressure. Kinda decreases the odds they are missing the center. But with such a pressure difference between dropsonde & extrapolated I still want to assume it's been hard to hit center. Probably not stacked so well. They are trying to hit it at ~10,000'.


Well the latest Vortex Message indicates an eye wall has redeveloped so with the presence of an actual eye maybe they'll hit the center better this time.
Member Since: September 2, 2008 Posts: 0 Comments: 744
Quoting barotropic:


Nothing really to prepare for.....if anything, keys marine interests may take note. If anything, gusty winds 30 - 35 mph, rough water and slightly higher tide. Looks like a pretty much non event either way. This storm hardly has a shot in hell to make it to Fla as anything but a slight pain in the neck.....
I wouldn't call it a non-event just yet, certainly nothing you have to prepare for I agree with that, but like I said earlier I'm interested to see what will happen with the interaction between the front and what is left of Rina, probably round 2 of Severe Weather in South FL. similar to 95L.
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I know everyone is focused on Rina but just 3 hours ago 97L had no vorticty at the 850 mb level but now is displaying very good and concentric vorticity. Maybe the development process has begun now.




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Quoting SunnyDaysFla:


Why don't you think the recon measurements are accurate?


Best example was when it was 960.8 yesterday and they never went that low.

Also today recon never said higher than 980mbs but they posted 982 as official pressure.

We will see what they post at 5pm I say 980mbs or 979mb unless recon does another pass and finds more of a drop cause its better now then 4hrs ago.
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It's getting sawed off, it's not coming back. Doesn't mean it has to weaken anymore, but it's going to have a hard time keeping intensification when the core is open. Hell, the entire storm right now is the core, the rest is sawed off.
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Quoting WoodyFL:


Looks like it might hit a small patch of very warm SST's.

Good catch Woody! IMO, it is now or never, the waters north of the Yucatan cool off significantly and doesn't get warmer again until the loop current, which by that time it will be a sheared storm.
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421. Skyepony (Mod)
Quoting cchsweatherman:


Most interesting to note is that the Hurricane Hunters have found an eye once again with Rina, albeit open, when the eye had not been there for quite some time. Maybe a sign of restrengthening to come.


And again it is fairly small. These eye drops too with the kinda higher winds & much higher pressure than extrapolated.. that was two in a row & same pressure. Kinda decreases the odds they are missing the center. But with such a pressure difference between dropsonde & extrapolated I still want to assume it's been hard to hit center. Probably not stacked so well. They are trying to hit it at ~10,000'.
Member Since: August 10, 2005 Posts: 193 Comments: 38700
rina now a cat 1 :P
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Quoting ProgressivePulse:
South Floridians should be taking this seriously and really should start preparing for the arrival of "Mid Level Center Rina" this weekend.

:-b


Nothing really to prepare for.....if anything, keys marine interests may take note. If anything, gusty winds 30 - 35 mph, rough water and slightly higher tide. Looks like a pretty much non event either way. This storm hardly has a shot in hell to make it to Fla as anything but a slight pain in the neck.....
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Also interesting to note is that a spiral feeder band has finally developed over the Yucatan and appears to be expanding in time. Definitely seeing signs that Hurricane Rina may be restrengthening this afternoon.
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Quoting reedzone:


It deff isn't weakening right now, either maintaining strength tonight or a bit more strengthening.


Looks like it might hit a small patch of very warm SST's.

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THE LATEST
*Click images to magnify (images can further be magnified in Link Window by clicking on them)

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Quoting GTcooliebai:
Are you sure it is not just maintaining its strength, I thought the same thing last night, and it ended up weakening?


It deff isn't weakening right now, either maintaining strength tonight or a bit more strengthening.
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Quoting scottsvb:


Rina can still hold her own and could get better organized before landfall.. but its a 50-50 chance.. Pressure is around 980mbs right now. Surface pressures are not exactly what you see listed. You have to add a few mbs upward on what is shown from recon


Why don't you think the recon measurements are accurate?
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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.