Tropical Storm Rina forms

By: Dr. Jeff Masters , 1:49 PM GMT on October 24, 2011

Tropical Storm Rina formed in the Western Caribbean Sea just off the coast of Honduras last night, and is headed north-northwest towards Mexico's Yucatan Peninsula. Rina's formation brings this year's tally of named storms to 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 29% of this year's named storms have made it to hurricane strength (five), 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.

Visible satellite loops show that Rina has had a respectable burst of thunderstorm activity with high, cold cloud tops this morning. This "Central Dense Overcast" (CDO) is characteristic of intensifying tropical storms that are a threat to reach hurricane strength. Rina has been bringing sporadic heavy rain squalls to the Cayman Islands over the past day; George Town on Grand Cayman Island had received 2.28" of rain and a peak wind gust of 31 mph as of 9 am EDT from the storm. 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. We don't have any surface wind reports from the vicinity of Rina; the closest buoy is Western Caribbean buoy 42057, about 60 miles east of Rina's center, which had top sustained winds out of the ESE at 29 mph this morning. We'll have to wait for the next hurricane hunter flight, scheduled for 2 pm this afternoon, to get a better idea of Rina's intensity.


Figure 1. Morning satellite image of Rina.

Forecast for Rina
The intensity forecast for Rina has a high amount of uncertainty. Rina should be able to slowly intensify through Tuesday, becoming a strong tropical storm. On Wednesday, Rina will be approaching a dry airmass with high wind shear that lies over the extreme northwestern Caribbean. Since Rina is a small storm, these hostile conditions could cause the storm to dissipate on Wednesday as it nears landfall over the Yucatan Peninsula, as predicted by the ECMWF and NOGAPS models. The completely opposite scenario is predicted by the GFDL and HWRF models, which forecast Rina will stay just south of the high shear/dry air region, and attain major hurricane status. The official NHC forecast of a Category 1 Hurricane Rina late this week is a reasonable compromise between these extremes. The track forecast for Rina also presents difficulties. A west-northwest to northwest motion towards the Yucatan Peninsula is likely through Wednesday. A trough of low pressure is predicted to pass to the north of Rina late this week, but the models are increasingly suggesting that Rina will not be far enough north to get caught up in the trough, but instead will remain trapped in the Western Caribbean. None of the latest 06Z (2 am EDT) model runs of the GFS, NOGAPS, GFDL, or HWRF models are predicting that Rina's center will make it north of Cuba during the next five days. In any case, heavy rains from Rina should begin affecting Mexico's Yucatan Peninsula, northern Belize, and extreme Western Cuba on Wednesday.

97L
A broad region of low pressure about 300 miles west of the southern Lesser Antilles Islands (Invest 97L), is moving west-northwest at 10 mph through the Caribbean Sea. This low has very limited heavy thunderstorm activity, due to dry air, and no signs of a surface circulation. NHC is giving 97L just a 10% chance of developing into a tropical depression by Wednesday. 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. The NOGAPS model predicts 97L could develop into a tropical depression by Saturday.

Jeff Masters

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GULP, GULP the dry air.....
Member Since: September 2, 2007 Posts: 179 Comments: 20528
Hurricane Rina now.
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Quoting Seflhurricane:
correct but the 12Z run has some more models shifting towards south florida, imagine the 8pm run with the new info


Scary thought.
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Tis a frightening strengthening trend indeed. Us Bahamians looking Southwest!
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The GFS stalls Rina in the Gulf of Honduras... This hurricane could be creepy....
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I would have to agree the camp has shifted again today.






Can't forget about 97 either (BAMMS only)


Member Since: August 19, 2005 Posts: 5 Comments: 6211
Quoting trHUrrIXC5MMX:
Wow. From 45 mph Rina jumps toa hurricane in less than 3 hours.
Now could make it to major hurricane?

The first time I ever see this since Humberto.


She didn't pull 45-75 in 3 hours. She was already close to hurricane status when the NHC advisory said she was still at 45. However, her overall intensification has been very rapid.
Member Since: November 24, 2005 Posts: 635 Comments: 26780
Quoting RitaEvac:
In 8 months, we'll be doing this all over again with the folks and crazies coming out just like they're right now


Rapid Intensification? By tonight the Blog will surely have ramped up into at least a MAJOR... LOL!
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Tomorrow is the 90th anniversary of the only reported hurricane to make landfall in Pinellas County.



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Can not think of a single system in the Atlantic that went from a 45 mph TS to a 75 mph Category 1 in the time between two advisory packages. Rina's strength has been very underestimated this morning..
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expect a change in the forecast track with parts of the florida keys included the model consensus has continued to now shift to a classic october system moving from the yucatan in responce to a trof towards South Florida and out to sea. one thing to note if this does verify we would likely see a weak hurricane or strong Tropical storm affecting south florida
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Quoting will40:


a lot of track updates dont change the track is that proof enough?


Ummm, no. You said they changed the track at 2:15, so you need to provide proof that the NHC has indeed changed the track, when it was them that said no change to the track was required. The only thing "track-wise" that "changed" is the initial position... other than that, nothing!

So the burden of proof is on you.
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Quoting reedzone:
Look at Wilma, under 40-50 knots of wind shear.. Again, don't use shear as an excuse to why you say it's not gonna affect the USA. Wilma was moving in the direction of the shear, which actually strengthened her. Same could happen with Rina, so the Yucatan, western Cuba, and South Florida should be watching this storm. Heck the Yucatan should be making preparations for a potential Major Hurricane.



There are two factors to consider: direction and magnitude. Storms that are moving NE appears to be less susceptible to southwesterly shear. Large storms are also less vulnerable to wind shear.

Wilma was quite large and it was moving generally northeast. You are right, Rina is somewhat more fortified from wind shear. However, given its small size and dry air, I think significant weakening north of Cuba is likely.
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and btw when they change the time of the track that is an update enuff said
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Wow. From 45 mph Rina jumps toa hurricane in less than 3 hours.
Now could make it to major hurricane?

The first time I ever see this since Humberto.
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Quoting ecflweatherfan:
Remember, the new models coming out right now still do not have Rina's rapid intensification factored into their tracks, e.g. we will have to wait until the 8pm ones to see the new info factored in.
correct but the 12Z run has some more models shifting towards south florida, imagine the 8pm run with the new info
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Member Since: June 9, 2007 Posts: 4 Comments: 16080
Academic at this point, but here you go:

AL, 18, 2011102418, , BEST, 0, 171N, 830W, 65, 991, HU, 64, NEQ, 15, 15, 0, 15, 1012, 225, 10, 0, 0, L, 0, , 0, 0, RINA, D,

And while we're at it:

AL, 97, 2011102418, , BEST, 0, 121N, 625W, 25, 1007, LO, 34, NEQ, 0, 0, 0, 0, 1010, 270, 150, 0, 0, L, 0, , 0, 0, INVEST, S,
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In 8 months, we'll be doing this all over again with the folks and crazies coming out just like they're right now
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Quoting reedzone:


No Adrian YOU STOP!!!! Bet you never thought this would reach Hurricane status by now did ya? Listen dude, I respect you, but you're going over the line. This has a chance to impact the USA, stop denying it. Mother Nature will win over climatology and science any day. Stop being so critical.
,any chance of significant impacts to the conus from rina is less than 1%,call your local nws if you dont believe me
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Wow...models clustering back on S. FL more now...

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Remember, the new models coming out right now still do not have Rina's rapid intensification factored into their tracks, e.g. we will have to wait until the 8pm ones to see the new info factored in.
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Quoting ecflweatherfan:


Then please prove to all of us on here where they actually changed the track. Because the only difference that I see between the 11am advisory from the NHC and the 2pm Special Advisory is the increase in intensity forecast.


a lot of track updates dont change the track is that proof enough?
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Member Since: September 18, 2010 Posts: 0 Comments: 6866
24 hr pounding for Cozumel

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Central Florida watch out, we used one of our last shields on that disorganized blob of ran last week. lol
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Quoting Seflhurricane:
some of the 12Z models have shifted east towards western cuba and moving across Southern Florida, also note the Hwrf has been consistent in predicting a hurricane in this area and i would really start to focus on that model on track
Greetings.. the shift and movement you are speaking of is that using the Hwrf model run? Thanks
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The Yucatan, western Cuba, and folks in South Florida definitely need to keep an eye on Rina. TCHP values are high and the environment is conducive to significant strengthening. I think we might see tracks shift more towards the Yucatan channel given the rate of Rina's intensification and the corresponding favorability of poleward movement.
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Quoting Stormchaser2007:
HWRF and GFDL take Rina into FL as a weak system.

FULL
we could use another good soaking we just started the dry season across South Florida so a weak system is welcomed
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Quoting will40:


simply that they didnt see a change in the last one


Then please prove to all of us on here where they actually changed the track. Because the only difference that I see between the 11am advisory from the NHC and the 2pm Special Advisory is the increase in intensity forecast.
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HWRF and GFDL take Rina into FL as a weak system.

FULL
Member Since: June 9, 2007 Posts: 4 Comments: 16080
Quoting Levi32:
And by the way, anything passing north of 22N IS likely to weaken. Let's not doomcast for Florida here. Right now it is still a bit too far off to worry about because we still have to see how Rina responds to her newfound strength. She still has dry air to deal with and what is likely to be a fairly close encounter with the Yucatan Peninsula. They are the ones we should be worried about right now as Rina pulls Humberto-like intensification.


And even after all that there'd still be the matter of Cuba. Rina would really have to thread the needle to verify a Florida doomcast.
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You are kidding me? Hurricane Rina this fast? Talk about your Humberto. This has happened at least once EVERY year since 2007. Humberto, Lorenzo, Gustav, Ida, Paula, and now Rina. Disturbing trend.

Probably will peak 110-115 imo.
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Quoting Some1Has2BtheRookie:



Uhhhhhh, it wasn't me but, what ya got in da bottle?


lol
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97L intensity forecast


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some of the 12Z models have shifted east towards western cuba and moving across Southern Florida, also note the Hwrf has been consistent in predicting a hurricane in this area and i would really start to focus on that model on track
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There's your deep convection...

Member Since: June 9, 2007 Posts: 4 Comments: 16080


Cone keeps shifting ever so slightly to the right!
Member Since: April 29, 2007 Posts: 0 Comments: 8647
The action is back. What a strange season...better late than never.
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Did Rina go backwards?
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Time to get out the POPCORN and Cola....the MOVIE is about to start....
Member Since: September 2, 2007 Posts: 179 Comments: 20528
Quoting gopher1:



kman you have been hitting the bottle early i see...RINA a hurricane by tonight i really dont think that will happen that soon...when recon goes in i think they will find a slight increase in strength winds of 50mph...IMHO



Hi Kman - see you only drink the good stuff eh? LOL
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Look at Wilma, under 40-50 knots of wind shear.. Again, don't use shear as an excuse to why you say it's not gonna affect the USA. Wilma was moving in the direction of the shear, which actually strengthened her. Same could happen with Rina, so the Yucatan, western Cuba, and South Florida should be watching this storm. Heck the Yucatan should be making preparations for a potential Major Hurricane.

Member Since: July 1, 2008 Posts: 13 Comments: 7546
New GFDL and HWRF 12zs taking Rina into South Florida.
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Funny thing is, they woulda kept it at 50 knots

AL, 18, 2011102412, , BEST, 0, 170N, 827W, 50, 1001, TS
Member Since: June 9, 2007 Posts: 4 Comments: 16080
Quoting ecflweatherfan:


HURRICANE RINA SPECIAL DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011
200 PM EDT MON OCT 24 2011

SATELLITE IMAGES AND REPORTS FROM AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT INDICATE THAT RINA HAS RAPIDLY STRENGTHENED. THE
AIRCRAFT REPORTED PEAK 850 MB FLIGHT-LEVEL WINDS OF 68 KT AND
BELIEVABLE SFMR WINDS AROUND 65 KT. BASED ON THESE DATA THE
INITIAL INTENSITY IS INCREASED TO 65 KT...MAKING RINA THE 6TH
HURRICANE OF SEASON IN THE ATLANTIC BASIN. THIS SPECIAL ADVISORY
HAS BEEN ISSUED TO INCREASE THE INITIAL AND FORECAST INTENSITIES
FROM THE PREVIOUS FORECAST...BUT NO CHANGE TO THE TRACK WAS
REQUIRED.



Then what do you make of this statement???


simply that they didnt see a change in the last one
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And by the way, anything passing north of 22N IS likely to weaken. Let's not doomcast for Florida here. Right now it is still a bit too far off to worry about because we still have to see how Rina responds to her newfound strength. She still has dry air to deal with and what is likely to be a fairly close encounter with the Yucatan Peninsula. They are the ones we should be worried about right now as Rina pulls Humberto-like intensification.
Member Since: November 24, 2005 Posts: 635 Comments: 26780
Quoting kmanislander:
Special advisory coming re upgrade. It's the track forecast I want to see after that.

I wonder if the blogger who accused me of drinking earlier today is around ?. He may want to borrow the bottle.
.lol.
Member Since: September 27, 2007 Posts: 1 Comments: 26897

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Dr. Masters (r) co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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