Subtropical Depression 17 forms; monsoon rains kill over 100 in Asia

By: Dr. Jeff Masters , 1:04 PM GMT on October 06, 2010

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Subtropical Depression Seventeen formed this morning, approximately 200 miles north of Puerto Rico. The storm is not a threat to bring high winds to any land areas, but will produce heavy rains over Puerto Rico, the Virgin Islands, the northern Lesser Antilles, and perhaps the eastern Dominican Republic. Radar estimated rainfall over Puerto Rico and the Virgin Islands (Figure 1) shows rainfall amounts in excess of eight inches have fallen near St. Thomas in the Virgin Islands, and the St. Thomas Airport officially measured 6.61" yesterday--its 5th wettest day in history. St. Thomas has picked up an additional 1.48" today as of 9am AST. Not surprisingly, Flash Flood Warnings are posted for the island. 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 this morning. Martinique radar shows somewhat less activity over the Lesser Antilles.

Satellite loops show STD 17 has a broad, somewhat ill-defined center of circulation, with the heaviest thunderstorms 50 or so miles from the 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 to the west of STD 17 has pumped cold, dry air aloft into STD 17, keeping it from being fully tropical. As the trough gradually weakens today and Thursday, STD 17 should become fully tropical and intensify into Tropical Storm Otto. Steering currents favor Otto being lifted northwards and then northeastwards out to sea by Friday.


Figure 1. Radar-estimated rainfall from Subtropical Depression Seventeen over Puerto Rico and the Virgin Islands shows that rains in excess of eight inches (white colors) have fallen near St. Thomas.

Elsewhere in the tropics
Most of the models indicate the possibility that a strong tropical disturbance or tropical depression forming in the Southern Caribbean, off the coast of Nicaragua, 5 - 7 days from now.

Monsoon flooding kills 83 in Indonesia, 28 in Vietnam
Heavy monsoon rains triggered flash flooding in a remote section of Indonesia this week that killed at least 83 people. Another 68 people are missing, and 3,000 homeless. In Vietnam, heavy rains of up to 51" (1300 mm) have fallen since Friday, resulting in river flooding that killed at least 28 people. 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 also hit nearby Hainen Island in China, forcing the evacuation of 64,000 people.

Jeff Masters

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Good morning

Another wet and windy day in the NW Caribbean but surface pressures at Grand Cayman are relatively high at 1010.6 mbs and rising rapidly. To our South buoy 42057 has a pressure of 1008 and steady.

Winds sustained out of the N generally around 18 mph gusting into the 20s. Very heavy rain now with 2.23 inches since midnight.

This is the time of year to watch what happens on the tail end of a cold front. Vorticity at 5000 feet fairly strong in this region and holding.
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We should have Paula by the beginning of next week from the wave in the W Caribbean. As Brian Norcross said on TWX, its going to meander because there is no well-defined steering flow.

South Florida needs to watch this one, because th e Jet Stream is expected to move north, and leave S FL out in the open, next week.
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962. Asta
Quoting beell:


PROGGED - Prognosis/The forecast
LIFTED INDICES - A measure of atmospheric instability.
KEPT POPS - Probability of precipitation

Oooh- Thanks!
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960. afj3
Quoting cat5hurricane:
Upper Level Divergence

Looks like it's forming ahead of schedule? What do you think will happen in SW Caribbean?
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959. beell
Quoting Asta:


.....PROGGED ???LIFTED INDICES ???...
and KEPT POPS ????



PROGGED - Prognosis/The forecast
LIFTED INDICES - A measure of atmospheric instability.
KEPT POPS - Probability of precipitation
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957. Asta
Quoting IKE:
New Orleans...


.....PROGGED ???LIFTED INDICES ???...
and KEPT POPS ????

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941. BOOOOOOOOO! LOL!
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I said to my dad that this would happen on this day at the same time at the same place

A SURFACE LOW PRESSURE TROUGH IS PRODUCING AN AREA OF SHOWERS AND
THUNDERSTORMS OVER THE WEST-CENTRAL CARIBBEAN SEA ABOUT MIDWAY
BETWEEN HONDURAS AND JAMAICA. DEVELOPMENT OF THIS DISTURBANCE...
IF ANY...SHOULD BE SLOW TO OCCUR AS IT MOVES SOUTHWARD AT 10 TO 15
MPH. THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

although I think that southward movment will change to either meandering or stationary then to a northward movment
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There ya go z-hills wcfl. Morning everyone
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Link

Crown Weather TWD for this morning.
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Quoting superpete:
Morning stormwatcher & everyone else.Feels like we are living inside a TD,doesn't it?
Yep, weather sure looks weird. ORIA reported 1.87" rain since midnight. Almost 19" for the month already.
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949. IKE
New Orleans...

LONG TERM...
CONTINUED TRENDS FOR WARMING TEMPERATURES OVER THE WEEKEND AS THE
SURFACE HIGH SLIDES EASTWARD TOWARD LOUISIANA. MODELS IN DECENT
AGREEMENT THAT THE HIGH WILL MOVE EAST OF THE REGION BY SUNDAY
INTO MONDAY WITH A RETURN TO ONSHORE FLOW EXPECTED. THIS WILL
BRING AN INCREASE IN LOW LEVEL MOISTURE AND HIGHER DEWPOINT
TEMPERATURES BY MONDAY.

AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL APPROACH
LATER MONDAY INTO TUESDAY. CONVERGENCE ALONG THE BOUNDARY COUPLED
WITH INCREASING MOISTURE WILL YIELD A DECENT CHANCE FOR SHOWER AND
THUNDERSTORM DEVELOPMENT MAINLY MONDAY AFTERNOON INTO TUESDAY
MORNING. PROGGED LIFTED INDICES PER THE 00Z GFS SOLUTION WERE -1
TO -3 AND HAVE ADDED THUNDER MENTION TO THE GRIDS FOR MONDAY
AFTERNOON AND MONDAY EVENING. KEPT POPS IN THE FORECAST MAINLY
ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE CWFA TUESDAY BEFORE
NORTHERLY FLOW AND DRYING TAKE SHAPE FROM NORTHWEST TO SOUTHEAST
LATER TUESDAY INTO WEDNESDAY. EXPECT A DRY NORTHERLY FLOW/OFFSHORE
COMPONENT TO REDEVELOP THROUGH THE LATTER HALF OF NEXT WEEK WITH
RATHER DRY AND PLEASANT CONDITIONS EXPECTED.
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947. IKE
"""A SURFACE LOW PRESSURE TROUGH IS PRODUCING AN AREA OF SHOWERS AND
THUNDERSTORMS OVER THE WEST-CENTRAL CARIBBEAN SEA ABOUT MIDWAY
BETWEEN HONDURAS AND JAMAICA. DEVELOPMENT OF THIS DISTURBANCE...
IF ANY...SHOULD BE SLOW TO OCCUR AS IT MOVES SOUTHWARD AT 10 TO 15
MPH.
THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS."""....
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Quoting stormwatcherCI:
Good morning. Shut down the computer early last night due to severe lightning but was surprised this morning by the blob sitting over the Cayman Islands, Winds here are 28 mph gusting to 39 mph. Pressure is 1006 mb. We had .98" rain since midnight last night and still lots of lightning.
Morning stormwatcher & everyone else.Feels like we are living inside a TD,doesn't it?
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Blog as dead as the MJO!!

In terms of US impacts predictions from most experts 2010 season would go down as a very disappointing one!!

Season over!

What to look forward to in the months ahead:
- Strong La-nina
- Sun spot activity is still very low and well below the predicted values and so is the Solar flux!!
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Quoting MahFL:


You forgot to say where you were, lol.


Across the pond.

Quoting IKE:


I figured the Ravens would beat Pittsburgh.
.............................................

Look at the dry-air....talk about a downward MJO...



I did such a dance around my living room when Flacco threw that last minute touchdown.

(American) football is slowly taking off here. You walk around the towns and cities and seeing football paraphernalia is no longer uncommon. Dolphins, Patriots, 49ers, Raiders... whole lot (though, I was taken by it way before they started to bring games to Wembley).

---

Yeah, mostly dry (except if you live in the CIs).



Not much coming in the next few days, either. Although, MJO hasn't been a real factor this year. Unlike 2008, where it seemed to be the source of every storm. As soon as the pulse came over, that was it, tropics were lit up.

That said, already halfway on the barometer of 'storms post-hyperactive September'. 2002 had none, 2007 had two. Probably see Paula later this month. Maybe Richard even further on or into the first week of November. Hope not though, 'R' names have been evil - Roxanne and Rita. Two occasions, two retirements.

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ABNT20 KNHC 071136
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT THU OCT 7 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON SUBTROPICAL
STORM OTTO...LOCATED ABOUT 235 MILES NORTHEAST OF GRAND TURK
ISLAND AND ABOUT 635 MILES SOUTH-SOUTHWEST OF BERMUDA.

A SURFACE LOW PRESSURE TROUGH IS PRODUCING AN AREA OF SHOWERS AND
THUNDERSTORMS OVER THE WEST-CENTRAL CARIBBEAN SEA ABOUT MIDWAY
BETWEEN HONDURAS AND JAMAICA. DEVELOPMENT OF THIS DISTURBANCE...
IF ANY...SHOULD BE SLOW TO OCCUR AS IT MOVES SOUTHWARD AT 10 TO 15
MPH. THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER STEWART

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I think the FAT LADY is warming up her vocal cords. I think I hear the music starting, and her about to sing.
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I don't think I've seen a storm name "Subtropical" before. Has there been one?
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935. IKE
Quoting Cotillion:


Yeah, I feel sympathy for them (despite being a Ravens fan). They're going in the right direction, though. Holmgren's doing good work.

And uhhh... it's the same temperature in Cleveland as it is here!


I figured the Ravens would beat Pittsburgh.
.............................................

Look at the dry-air....talk about a downward MJO...

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Quoting IKE:


I feel sorry for the Browns. I feel for the city after LeBron flipped them off the way he did.


Yeah, I feel sympathy for them (despite being a Ravens fan). They're going in the right direction, though. Holmgren's doing good work.

And uhhh... it's the same temperature in Cleveland as it is here!
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931. MahFL
Quoting Cotillion:
Hey everyone.

Real nice day here, amazingly. Says it's about 57, but it feels warmer. Hardly a cloud in the sky and a bit of a breeze. Lovely autumnal day.

Tomorrow's high, supposedly, is approaching 70. 70!? In October? I don't remember a 70 for the entirety of July (The fabled 'Return of the Westerlies' - aka 'European Monsoon' - does generally screw up one 'summer' month).

I'm not complaining, though. :)

Good thing we have high pressure, too.



Beast of a low, right there. Approaching Alex's pressure. No sign of Otto (or its extratropical form) just yet on the charts.


You forgot to say where you were, lol.
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Quoting aislinnpaps:


StormwatcherCI, I'll be watching for that box! *G*



Ike,
I'm looking forward to it! I love to open the windows and doors, turn on the attic fan and pull all the fresh air in.
It has started raining again. Anyway, have a good day with your "kids".
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929. IKE
Quoting Cotillion:


You woulda thought it'd be an orange helmet instead... Link

Maybe he took to the Colts in his Redskins tenure... (as they were next door back in those days).


I feel sorry for the Browns. I feel for the city after LeBron flipped them off the way he did.
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Quoting IKE:


Otto w/a helmet...Link


You woulda thought it'd be an orange helmet instead... Link

Maybe he took to the Colts in his Redskins tenure... (as they were next door back in those days).
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927. IKE
Quoting aislinnpaps:


StormwatcherCI, I'll be watching for that box! *G*



Ike,
I'm looking forward to it! I love to open the windows and doors, turn on the attic fan and pull all the fresh air in.


Sounds like a winner to me!
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926. IKE
He may need some Curel for his hands....



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Quoting stormwatcherCI:
We were very dry down here the first several months of the year but finally started getting some around June and it has been basically a few days every week since then. The first rain we got this year was from Alex. I will check with Fed-Ex today to see if I can send some through them. Hmmm, now to find a big enough box.


StormwatcherCI, I'll be watching for that box! *G*

Quoting IKE:
If you live along the northern GOM it looks like a real nice weekend, with highs back into the mid-upper 80's.

Then Tuesday into Wednesday of next week another cold/cool front makes it through the area, with small chances of rain, cooling it back down and more dry air after it's moved through.

No tropical threats. 98% chance it's over for here.


Ike,
I'm looking forward to it! I love to open the windows and doors, turn on the attic fan and pull all the fresh air in.
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924. IKE
Quoting Cotillion:
Otto must have a picture of Peyton Manning in his bedroom.


Otto w/a helmet...Link
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Quoting CybrTeddy:


So did Darth Vader.



Good morning. Darth Vader, GWB quotes, 44 degrees at my homestead and a SUBtropical Storm Otto. It is indeed an odd morning.

I like it. :)
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Otto must have a picture of Peyton Manning in his bedroom.
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921. IKE
Quoting Cotillion:


Is that him trying to make the Omega symbol?

What a clever boy.


A horseshoe on water vapor....




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Quoting IKE:
He does look rather anemic...sorry Otto, I'm not perfect either...lol...not sure I could say he will become tropical...



Is that him trying to make the Omega symbol?

What a clever boy.
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919. IKE
Quoting PakaSurvivor:


Ike, please stop with the doom and gloom! Ha!
Was 39F when I got up and I really need it to warm up a little more and you're forecasting more cold!


Cooling back down may mean highs near 80 and lows in the low 50's:)
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918. IKE
He does look rather anemic...sorry Otto, I'm not perfect either...lol...not sure I could say he will become tropical...

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Quoting IKE:
If you live along the northern GOM it looks like a real nice weekend, with highs back into the mid-upper 80's.

Then Tuesday into Wednesday of next week another cold/cool front makes it through the area, with small chances of rain, cooling it back down and more dry air after it's moved through.

No tropical threats. 98% chance it's over for here.


Ike, please stop with the doom and gloom! Ha!
Was 39F when I got up and I really need it to warm up a little more and you're forecasting more cold!
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Quoting Cotillion:
Otto looks pathetic.
He looks more like a strong cold front.
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Otto looks pathetic.
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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.