Otto transitioning to a tropical storm
Subtropical Storm Otto, the 15th named storm of this very busy 2010 Atlantic hurricane season, is here. Otto is not a threat to bring high winds to any land areas, but will produce heavy rains over Puerto Rico, the Virgin Islands, and northern Lesser Antilles. Radar estimated rainfall over Puerto Rico and the Virgin Islands (Figure 2) shows rainfall amounts in excess of eight inches have fallen in several locations over the past three days, and the St. Thomas Airport officially recorded 9.30" of rain so far from Otto. Not surprisingly, Flash Flood Warnings are posted for both the Virgin Islands and Puerto Rico. Weather radar out of Puerto Rico shows that a large area of heavy rain will continue to affect the Virgin Islands and eastern Puerto Rico today. Martinique radar shows considerably less activity over the Lesser Antilles.
Figure 1. NASA MODIS image of Subtropical Storm Otto taken at 12:55pm EDT October 6, 2010.
Satellite loops show Otto's heaviest thunderstorms lie in two bands to the south, many hundreds of miles from the storm's center. This is characteristic of a subtropical storm, which is a hybrid between a tropical storm and an extratropical storm. An upper level low pressure system over Otto has pumped cold, dry air aloft into the storm, keeping it from being fully tropical. However, the upper low is weakening, and Otto has recently developed a burst of heavy thunderstorms near its center, and very tropical storm-like spiral bands are now developing to the east and south of Otto's center. Otto is fast becoming fully tropical, and will be called Tropical Storm Otto later today. The storm's newly developing spiral bands will mostly stay offshore, but a few heavy rain showers capable of dumping 1 - 2 inches of rain may affect the Turks and Caicos Islands today, as well as the northern Dominican Republic. The heavier rains in Otto's old rain band over Puerto Rico and the Virgin Islands will continue to dump flooding rains in those locations through tonight. Steering currents favor Otto being lifted northwards and then northeastwards out to sea by Friday. Given the very warm waters of 28 - 29°C and low wind shear of 5 - 10 knots today, Otto may approach hurricane strength before high wind shear in excess of 20 knots impacts the storm Friday night.
Figure 1. Radar-estimated rainfall from Tropical Storm Otto over Puerto Rico and the Virgin Islands shows that rains in excess of eight inches (white colors) have fallen in many regions. The strange ray-like pattern to the east of the radar location (the white "+" symbol) is due to mountains blocking the radar beam.
Elsewhere in the tropics
An area of disturbed weather has formed in the Western Caribbean, a few hundred miles west of Jamaica. The disturbance has a moderate area of intense thunderstorms that brought close to two inches of rain to Grand Cayman Island over the past day. The disturbance is under a high 15 - 25 knots of wind shear, and is not likely to develop significantly today. The disturbance is headed south at 10 - 15 mph, and will bring heavy rains to northeastern Honduras and Nicaragua over the next two days. None of the models develop the disturbance, but it does have some potential for slow development beginning on Friday when it will be off the coast of Nicaragua, in a region of lower wind shear and higher moisture. NHC is giving the disturbance a 10% chance of developing into a tropical depression by Saturday.
Monsoon flooding kills 139 in Asia
Heavy monsoon rains triggered flash flooding in a remote section of Indonesia this week that killed at least 91 people and left 100 more missing. In Vietnam, heavy rains of up to 51" (1300 mm) have fallen since Friday, resulting in river flooding that killed at least 48 people, with 23 people still missing. Over 34,000 people are homeless from the floods, which hit five provinces from Nghe An to Thua Thien-Hue, a swath of territory starting some 300 km (180 miles) south of Hanoi and stretching south. Heavy monsoon rains of up to seven inches over the past week have also hit nearby Hainen Island in China. The resulting flooding was the worst in 50 years there, and killed one person and forced the evacuation of 55 villages with 213,000 people.
Press
I've been a subscriber for several years to NewScientist magazine, a weekly science news magazine that does a great job staying abreast of all the latest breaking science happenings. This week's October 4 issue features a 4-page section on Extreme Weather that I wrote for them as part of their "Instant Expert" series. If you haven't ever seen the magazine, I enthusiastically recommend taking a look.
If you're a fan of the geek humor xkcd webcomic, see if you can find me on the hilarious map of the "blogosphere" on comic artist Randall Munroe's latest xkcd comic. I like the disparity between my influence in September vs. March, but thought I should have been closer to the "Bay of Flame!" I also appeared in a mouse "rollover" text box in an xkcd comic during the Gulf oil disaster earlier this year.
Jeff Masters
Reader Comments
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Anyway, with that tidbit out of the way, here's the current season visual:
With high shear present, this could be the Peninsula's first active front.
Not where you think it will be.
I may have used the wrong word; I didn't mean "incredible" as in non-credible; I meant it as a synonym for "amazing"... :-)
And you, sir, are a hard man. A hard man indeed.
7Oct 03amGMT - - 23.5n68.2w - - 65mph - - - - 990mb -- NHC.Adv. #4
7Oct 06amGMT - - 23.5n68.2w - - 55knots - - - 990mb -- NHC-ATCF
7Oct 09amGMT - - 23.6n68.2w - - 60mph - - - - 992mb -- NHC.Adv.#5
7Oct 12pmGMT - - 23.6n68.3w - - 50knots - - - 992mb -- NHC-ATCF
TS.Otto
7Oct 03pmGMT - - 23.8n68.0w - - 60mph - - - - 992mb -- NHC.Adv.#6
7Oct 06pmGMT - - 23.6n67.9w - - 50knots - - - 992mb -- NHC-ATCF
7Oct 09pmGMT - - 24.0n67.6w - - 60mph - - - - 992mb -- NHC.Adv.#7
8Oct 12amGMT - - 23.8n67.1w - - 50knots - - - 992mb -- NHC-ATCF
8Oct 03amGMT - - 24.1n66.6w - - 60mph - - - - 992mb -- NHC.Adv. #8
65mph=~104.6km/h __ 55knots=~63.3mph=~101.9km/h
60mph=~96.6km/h __ 50knots=~57.5mph=93.6km/h
MaximumSustainedWind speeds are rounded to the nearest 5mph or to the nearest 5knots
Copy&paste 23.5n68.2w, 23.5n68.2w, 23.6n68.2w, 23.6n68.3w, 23.8n68.0w-23.6n67.9w, 23.6n67.9w-24.0n67.6w, 24.0n67.6w-23.8n67.1w, 23.8n67.1w-24.1n66.6w, bqn into the GreatCircleMapper for a look at the last 12hours.
The abrupt zig-zagging is most likely due to disagreement about center positions between those who put together the NHC.ADV. and those who put together the NHC-ATCF
You are 100% correct!
Close to 40 roads have been closed in PR, with mudslides, down trees, several rivers are at flood stage or above it, some families are at shelters and the worse part is it isn't over.
*This is primarily in the south side of the island.
Best Wishes down there.
It's astounding how much Otto's canopy has ballooned the past few hours.
Long way to go...
I have posted a very detailed look at Otto, I think this storm has been interesting to a lot. If you are confused as to why Otto has done what it has, hopefully you can find some answers and learn something new tonight through the study of Otto on my post.
Inside Joke between you and me:
At least it won't be a 400-mile diameter eye, LOL.
Just Kidding :)
Yeah, 100% agree. Otto's upper structure has done a complete 180 in the last several hours that has allowed it to do this. The upper low over Otto that was once suppressing its convection has now been overtaken by the upper trough approaching Otto from the west. Now, Otto is free to breath aloft, no more upper low capping the convection.
Season Weather Averages for Luis Munoz Marin International (TJSJ)
Climate change my friend.
Pun intended.
Well, yesterday someone wrote that in extra tropical systems the eye is not in the center of the storm, but that the strenght is in the outside.... So I will be checking Otto, for when it reaches 400 miles ....
Still looks like a weak tropical storm to me on Satellite, no budding eye feature, shear present.
Are you serious or joking? IMO, I wouldn't have anything in my gut telling me that. Don't see the sea-surface temps in the future or wind shear levels supporting something that strong.
MARK
24.55N/65.66W
I have always wondered why extratropical systems have max strength not at the center. Never could find a good answer on that one. Hmmm...
Wow wow wow, phew! Otto's canopy is freakin' blowin up in size in those last few sat. loop frames. Again, wow! Storms like Otto are cool to watch.
near hurricane status
I'm gonna need that. In my final paragraph of my blog post, I predicted Otto will become a hurricane. Not might, but will.
Yeah, thinking cat one later on the 8th. But by 5 AM, probably will still be tropical storm Otto, but a stronger tropical storm Otto.
Link
Tropical Cyclone Advisory #5
DEPRESSION BOB02-2010
5:30 AM IST October 8 2010
======================================
Subject: Depression Over Northwest Bay Of Bengal
At 0:00 AM UTC, Depression BOB02-2010 over west central & adjoining northwest Bay of Bengal moved northeastwards and lays centered over northwest Bay of Bengal near latitude 20.0N and 86.5Em or close to Paradeep.
The current environmental condition and numerical weather prediction models suggest that the system would move in north northeasterly direction and cross West Bengal coast near Sagar Island later this afternoon
Viewing: 501 - 551
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