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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@NEwxguy: while it's true that the chance we in the CONUS won't have to worry increase with each passing day, I'd say by no means are we out of the woods. Yes, a major northern GOM strike is highly unlikely based on climatology...but pretty much everywhere else is still fair game for a damaging and/or deadly tropical/subtropical/extratropical hit. IOW, I don't think we're anywhere near being able to signal "All clear!" just yet...
AOI
TS BUSTED FORECAST ALIBI
I still think a Hurricane is possible, major Hurricane, probably not. I do believe a Major Hurricane will form eventually in the Western Caribbean sometime this month or early next month. If it moves north, will likely weaken to a Hurricane just like the rest did in years past. Ida is a good example, however shear was another problem for that one. If shear isn't an issue which I highly doubt it won't be, the storm wouldn't weaken that much. If Ida were to enter just cooler waters, with the pace she was going, she would have made it fully Tropical and a Hurricane in the FL Panhandle, gave them quite a scare last year. So we are definitely not out of the woods yet. 2 more months to go, I wish people would stop bragging on the season being over for us, we are still at a good risk for a landfalling TC.
The current NHC forecast is that it will be a hurricane soon because it is not moving fast/staying over warm water and subject to almost no shear. Those T-storms ballooning up in the center of the current loops seem to indicate the transition to tropical.
Correction here. I said "whatever is left of Matthew, whether it be the new system forecast to form near it or the remnants of Matthew itself, will eventually in time head north."
Nicoles moisture did indeed eventually pull northward.
Thanks again,
v/r
Moe
carb blob goes south hmmmm next
You're going up in the world, Doc.
Correct..and likely to be 15/8/5 as of tomorrow. By way of comparison, the 1950-2009 average is 10/6.2/2.7. (Yes, there were likely some smaller storms missed in the pre-satellite days, so if you want add another two or even three named storms to the average, go ahead...and we're still above it, with nearly two months left in the season.)
You would think they would give these guys a respirator or something.
We got wind gusts close to 40mph in our location here in Eastern Puerto Rico, this occurred at 433 am.
Look at the cooling of the Gulf in the last 10 days - Houston's been reporting temps in the upper 40s in early mornings! LMAO!!
from its previous heading of dueNorth
TS.Otto's average speed moving between its last 2 reported positions increased to ~3.2mph(~5.1km/h)
from its previous moving speed of ~1.2mph(~1.9km/h)
Invest 97L -- 6hours between consecutive center positions
5Oct 06pmGMT - - 20.6n65.7w - - 30knots - - 1004mb -- NHC-ATCF
6Oct 12amGMT - - 21.4n66.2w - - 30knots - - 1002mb -- NHC-ATCF *21.5n66.1w
6Oct 06amGMT - - 21.9n66.7w - - 30knots - - 1001mb -- NHC-ATCF
StD.17 -- 3hours between consecutive center positions
6Oct 12pmGMT - - 22.2n67.0w - - 35mph - - - 1001mb -- NHC.Adv.#1
6Oct 03pmGMT - - 23.0n68.0w - - 35mph - - - 1001mb -- #2
StS.Otto -- 6hours between consecutive center positions
6Oct 09pmGMT - - 23.2n68.3w - - 60mph - - - - 990mb -- #3
7Oct 03amGMT - - 23.5n68.2w - - 65mph - - - - 990mb -- #4
7Oct 09amGMT - - 23.6n68.2w - - 60mph - - - - 992mb -- #5
TS.Otto
7Oct 03pmGMT - - 23.8n68.0w - - 60mph - - - - 992mb -- #6
* Before NHC reevaluated&altered the ATCF numbers.
30knots=~34.5mph=~55.6km/h __ 35mph=~56.3km/h __ 60mph=~96.6km/h __ 65mph=~104.6km/h
Copy&paste 20.6n65.7w, 21.4n66.2w, 21.9n66.7w, 22.2n67.0w, 23.0n68.0w-23.2n68.3w, 23.2n68.3w-23.5n68.2w, 23.5n68.2w-23.6n68.2w, 23.6n68.2w-23.8n68.0w, nas, mhh into the GreatCircleMapper for a look at the last 24hours.
Indeed we are, as well as being ahead of the 1995-2009 average of 14-8-4.
This time it looks like Wind Shear is a bit lower and steering currents at westward all the way through to the southern Antilles.
This one seem better organised - at this time - than the others from last week and with more cloud area under its influence too.
Server error?
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