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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

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Rina continues to intensify, and is likely a 80-85mph cyclone.
Quoting StormGoddess:

Just walked in and I see this. What the?

There comparing this to that monster, because of the short time length this thing took to get to cat 1.
Very unexpecting.
Quoting kmanislander:
Did anyone notice that the new pressure reading of 989 mbs was found to the North East of the first reading of 991 and very close to it. ??

Rina may be stalled or meandering


i noticed that Kman about 1.7 miles NE of previous fix its just sitting there wobbling around right now
Rina is a small hurricane. For her to have any chance of surviving whats to come she needs to beef up quite a bit,and I'm not sure that would even save her.If she can handle the dry air,40kts of shear and still make it to Florida,Cuba as a Cat 1 hurricane,KUDO'S to her!
Quoting rtilryarms:


Did you not watch Bronco's vs Dolphins?


I'ma Dolphin fan.. I laughed HARD at that you cold hearted person.
507. Gorty
According to Henry's tweet, the models now have snow for NYC on Saturday and also for NY and New England on Friday.
So in nearly two hours time the center has moved just under two miles. 1 MPH to the NE. Going to take a while to get anywhere at this pace...


Vortex Message Fix as of 3:27 pm EDT

B. Center Fix Coordinates: 1708'N 8302'W (17.1333N 83.0333W) (View map)


Vortex Message Fix as of 1:40 pm EDT

B. Center Fix Coordinates: 1707'N 8303'W (17.1167N 83.05W)
Quoting Articuno:

There comparing this to that monster, because of the short time length this thing took to get to cat 1.
Very unexpecting.

Oh.
Ok.
Thank you for the clarification. Yes, it is quite surprising that Rina has intensified so quickly all of a sudden.
Quoting rtilryarms:

Quoting rtilryarms:


Did you not watch Bronco's vs Dolphins?


I'm sorry but I had to comment, that is funny!
Quoting StormGoddess:

Oh.
Ok.
Thank you for the clarification. Yes, it is quite surprising that Rina has intensified so quickly all of a sudden.

;)
Quoting rtilryarms:


Did you not watch Bronco's vs Dolphins?


ROFL, i'll admit that was a good one. I was at the game. Once the Dolphins get Luck, the team and results will be different.
models r clustered intill it is just off cozumel..

Quoting Saltydogbwi1:


i noticed that Kman about 1.7 miles NE of previous fix its just sitting there wobbling around right now


No surprise if Rina has stalled. Here is the new steering layer for the current pressure. You can see the weakness very clearly oriented to the NNE with the shortwave digging down in between the two ridges.



Quoting StormGoddess:

Oh.
Ok.
Thank you for the clarification. Yes, it is quite surprising that Rina has intensified so quickly all of a sudden.


And in the same general area and with close projected paths.
Quoting ProgressivePulse:



I am not speaking with absolute certainty, I "NEVER" speak for certain about the tropics. You asked my current opinion which is that I don't think it will come up this far however, I want to see how the next couple days unfold. I very well could come up this far however, Day 5, Rina is still in the Yucatan Channel and ample time to prepare should it make a move this way.

There was nothing certain about my response...


=)
Hurricane Rina lies just outside of that circle of 100-105+ TCHP values:

Quoting kmanislander:


No surprise if Rina has stalled. Here is the new steering layer for the current pressure. You can see the weakness very clearly oriented to the NNE with the shortwave digging down in between the two ridges.





I wonder how far west she will go with steering like that she may just meander around the western carib a while slowly moving somewhat northerly but im no pro at reading those maps what do you think Kman?
Quoting kmanislander:


No surprise if Rina has stalled. Here is the new steering layer for the current pressure. You can see the weakness very clearly oriented to the NNE with the shortwave digging down in between the two ridges.





Does this interpret into a more northern or westwern direction?
More comparing:

Wilma at it's 8th advisory was a TD still.
On the other hand Rina at it's 8th advisory was a CAT 1 hurricane.

Wilma didn't explode until 2 days after it formed.
Quoting TropicalAnalystwx13:
Hurricane Rina lies just outside of that circle of 100-105+ TCHP values:


And is moving right into it....
NEW BLOG!
Quoting Articuno:
More comparing:

Wilma at it's 8th advisory was a TD still.
On the other hand Rina at it's 8th advisory was a CAT 1 hurricane.

Wilma didn't explode until 2 days after it formed.


interesting...
Gonna go fire the generator tonight and make sure she good to go again. Cape Coral here....Wilma showed me what late season storm can and will do. The backside is nice...but windy.

Not liking the "record" breaking storm already.
Quoting PantherGraduate:


Big K, que bola? Speaking of which, do you guys down there in the Cayman Islands have a big Cuban population, or not?

In terms of Rina, what weather is she giving y'all down there this afternoon.


Hi, very few Cubans here but several Caymanian families have Cuban connections. As for the weather, right now fairly calm but overcast.
Notice the latest fix is NE of the first one with a 3mb drop, not good news :(
So far, Rina has done her own thing. She has consistantly proved the models and experts wrong.

She's gone from a storm many thought wasn't worthy of being a T.D yesterday to a hurricane in one day.

My weekend better not get ruined...

• 12z HWRF & GFDL.

Both models have the cyclone reaching a peak intensity in the 2-3 day time frame (sub-945mb pressure).



519 and 520

A stall typically precedes a track change but not always. The high to the West might serve as a blocker to progress in that direction unless it can build over the top of the hurricane fairly soon.

It looks as if the influence of the steering from the East is about equal to that from the West with the shortwave trying to exert some pullon Rina.

Some motion to the N NNE or NNW would not be out of the realms of possibility now. Let's see what the HH finds on the next pass near the centre but probably very little if any movement since the last pass.

Will be back later
Quoting Gorty:
According to Henry's tweet, the models now have snow for NYC on Saturday and also for NY and New England on Friday.


Was looking at the forecast soundings. Too warm in the boundary layer (nearly isothermal below 900) for NYC and the Bouroughs, but maybe northwest of the Metro and of course in the Poconos on to the northeast.
Quoting ClaySFL:


ROFL, i'll admit that was a good one. I was at the game. Once the Dolphins get Luck, the team and results will be different.


Yea, I was there too. If that was not divine intervention I will never know what is.

The Epiphany Bowl
Quoting Mucinex:

Umh, excuse me, but how many teams have thrown a mid-field party for the opposing quarterback (Tebow) and then cheer him on to victory? The Dolphins have pushed the "S*ck for Luck" vortex over Dolpins stadium to Cat6+ rating.;)
The best thing that will happen if we get a storm in SFL is that the cable will be out for the Dolphins away game.
LOL LOL
Quoting LargoFl:
weather guy on the local radio said a ..monster Hurricane is forming..his words....time to start paying attention


I don't know where this "weather guy" is, or how he's qualified to make such statements. If he's refering to Florida, there is no "monster hurricane" forming. I would be a lot more worried if I lived in Belize or the Yucatan, but we're talking about a storm, if it survives, that is at least seven days out from getting anywhere near Florida. The accuracy of seven day hurricane forecasts is about the same as a flipping a coin. No need to get a milk and bread panic started yet. :)
Evening all.
Quoting Thrawst:
Massive rainshower ever since 3:00 or so ... my backyard is flooded -_-.
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....