TD 16 organizing; Mexican landslide kills hundreds; hottest day ever in Los Angeles

By: Dr. Jeff Masters , 7:25 PM GMT on September 28, 2010

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The large area of low pressure centered just south of Cuba's Isle of Youth has developed enough of a well-defined circulation to be classified as Tropical Depression Sixteen, and is likely to become Tropical Storm Nicole by Wednesday. The depression has a very broad center, with little heavy thunderstorm activity near the center, and is this very dissimilar to the usual types of tropical depressions we see in the Atlantic. The large size, broad center, and lack of heavy thunderstorm activity near the center of TD 16 will limit the storm's ability to rapidly intensify. TD 16 resembles the "monsoon depressions" common in India's Bay of Bengal or the Western Pacific. A monsoon depression is similar to a regular tropical depression in the winds that it generates--about 30 - 35 mph near the outer edges (and usually stronger on the eastern side of the circulation.) Monsoon depressions have large, calm centers, and can evolve into regular tropical storms, if given enough time over water to develop a tight, closed circulation. Today's monsoon-like depression in the Caribbean was able to form because the atmospheric flow pattern of the Eastern Pacific has shifted eastwards into the Western Caribbean, bringing in the Eastern Pacific ITCZ (Intertropical Convergence Zone, a region of converging surface winds that creates a band of strong thunderstorms). This unusual flow pattern is forecast to remain in place for at least the next ten days.

An Air Force hurricane hunter aircraft has been flying at 700 feet in TD 16 since 1:30pm EDT, and has thus far found a central pressure of 999 mb. The strongest winds at flight level seen as of 3:20pm EDT were 32 mph, located about 100 miles east of the center of TD 16. Surface observations show that the strongest winds at any surface station continue to be at Buoy 42057, several hundred miles to the southeast of TD 16's center. Winds were 27 mph, gusting to 34 mph at 2:43pm EDT this afternoon. Rotation of TD 16 can be seen on radar loops out of Pico San Juan, Cuba, and well as satellite imagery. The heavy thunderstorms are currently quite disorganized, but a curved band is beginning to wrap around the north side of the center, signaling that TD 16 is growing more organized. TD 16 has brought torrential rains to the Cayman Islands, Jamaica, Cuba, and Honduras today.


Figure 1. Radar-estimated precipitation for South Florida and Cuba. TD 16 has brought 2 - 4 inches of rains to the region.

Forecast for TD 16
Because TD 16 is so large, it will take more time than a typical depression for it to spin up into a strong tropical storm. Given that the steering currents are expected to pull TD 16 north-northeastwards over Cuba and into South Florida and the western Bahamas on Wednesday, the storm lacks sufficient time over water to be any stronger than a 50 mph tropical storm for Florida. TD 16 is organizing pretty slowly this afternoon, and I think the top winds in Southeast Florida are most likely to be in the 25 - 35 mph range on Wednesday. Winds are likely to be stronger in the western Bahamas, perhaps 30 - 40 mph, since they will be in the stronger right front quadrant of the storm. By the time TD 16 makes landfall in South Carolina or North Carolina on Thursday morning, it could be as strong as a 50 - 60 mph tropical storm. However, wind shear will increase sharply on Thursday as TD 16 gets caught in an upper-level trough of low pressure, and NHC is giving TD 16 only a 9% chance of making it to hurricane strength before it becomes an extratropical storm on Thursday. The primary danger from TD 16 is not wind, but heavy rainfall. A potent upper-level low and stationary front over the U.S. East Coast have been pulling moist, tropical air from the Caribbean northwards over the past few days, bringing heavy rains that have saturated the soils. This is called a Predecessor Rain Event, or PRE, since it comes in advance of the actual rain shield of the storm. (A PRE from Hurricane Karl brought southern Wisconsin the heavy rain that caused the levee on the Wisconsin River to fail yesterday.) Wilmington, NC received 10.33 inches of rain yesterday, its second greatest one-day rainfall since record keeping began in 1871. Only the 13.38" that fell during Hurricane Floyd on September 15, 1999 beat yesterday's rainfall total. With TD 16 expected to bring another 6 - 8 inches of rain to the region later this week, serious flooding is likely, and flash flood watches are posted for the North Carolina/ South Carolina border region. South Florida is also under a flood watch, for 3 - 5 inches of rain. Flooding rains of similar magnitude can also be expected in Cuba, the Cayman Islands, and the Western Bahamas through Wednesday night. Both the GFDL and HWRF models are predicting that TD 16 will dump rains in excess of eight inches along narrow portions of its path in eastern Florida, South Carolina, and North Carolina.


Figure 2. Forecast precipitation for the 5-day period from 8am today through 8am EDT Sunday, October 3, 2010. Image credit: NOAA Hydrometeorological Prediction Center.

Up to 1,000 feared dead in Mexican landslide
Mexico has taken the brunt of the devastation from the hurricane season of 2010, thanks to the landfalls of this year's two deadliest and most damaging storms, Hurricanes Alex and Karl. But Mexico's worst blow yet hit this morning, when heavy rains from the remnants of Tropical Storm Matthew triggered a landslide in Mexico's mountainous Oaxaca state that buried as many as 1,000 people in Santa Maria Tlahuitoltepec, a town of 9,000. Rescuers have not reached the area yet, but hundreds are feared dead in the 300 homes that were buried by the early morning landslide. Matthew hit Belize on Saturday as a minimal tropical storm with 40 mph winds, and dissipated Sunday over southern Mexico. However, Matthew's remains stalled out over the region of Mexico that had already received torrential rains from Hurricane Karl, which hit on September 18. Satellite estimates of Matthew's rains over southern Mexico (Figure 3) show that a foot of rain may have fallen in the landslide area. Matthew's remains still linger over the region, but are probably only capable of bringing 1 - 2 inches of additional rain through Thursday.


Figure 3. Satellite-estimated rainfall for the five-day period ending at 8pm EDT Monday September 27, 2010. The dark green colors show where rainfall amounts of 300 mm (about 12 inches) fell, due to the remnants of Tropical Storm Matthew. Image credit: Navy Research Lab, Monterey.

Elsewhere in the tropics
Once TD 16 moves out of the Caribbean, the GFS model predicts that the Western Caribbean will "reload" and produce another tropical disturbance capable of developing into a tropical depression early next week. The GFS also predicts a tropical or subtropical storm will form over the Bahamas late this week, and move north-northeast along the U.S. East Coast, missing hitting land. The NOGAPS model hints at the Bahamas storm, and also predicts development of a tropical wave a few hundred miles northeast of the Lesser Antilles Islands, about a week from now.

Hottest day in Los Angeles history
The mercury hit a blistering 113°F (45.0°C) at 12:15 pm PDT yesterday in downtown Los Angeles, making it the hottest day in Los Angeles history. It may have gotten hotter, but the thermometer broke shortly after the record high was set. The previous record in Los Angeles was 112°F set on June 26, 1990; records go back to 1877. Nearby Long Beach tied its hottest all-time temperature yesterday, with a scorching 111°F. And Christopher C. Burt, our new featured blogger on weather records, pointed out to me that a station in the foothills at 1260' elevation near Beverly Hills owned by the Los Angeles Fire Department hit 119°F yesterday--the hottest temperature ever measured in the Los Angeles area, tying the 119°F reading from Woodland Hills on July 22, 2006. Yesterday's record heat was caused by an unusually large and intense upper-level high pressure system centered over Nevada that generated winds blowing from the land to the ocean, keeping the ocean from exerting its usual cooling influence. Remarkably, Los Angeles had its second coldest summer on record this year, and temperatures just five days ago were some the coldest September temperatures in the region for the past 50 years.

The remarkable summer of 2010
Wunderground is pleased to welcome a new featured blogger--weather historian Christopher C. Burt. Chris is a leading expert in the U.S. on weather records, and is author of the world's most popular weather records book published to date, Extreme Weather: A Guide and Record Book. He's spent a lifetime collaborating with like-minded individuals from around the world, and no one--including official sources such as the National Climatic Data Center and the National Extremes Committee--has done as thorough a job correlating the various weather records available and determining the most accurate extreme values of such. Each month he'll be reporting on the notable records for heat, cold, and precipitation set world-wide, and his first post takes a look at the remarkable summer of 2010. It's great to have someone like Chris who stays on top of weather extremes, and I hope you'll pay a visit to his blog and welcome him to the wunderground site!

"Hurricane Haven" airing this afternoon
My live Internet radio show, "Hurricane Haven", will be airing again today at 4pm EDT. The call in number is 415-983-2634, or you can post a question to broadcast@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line.

Today's show will be about 30 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

I'll have updates as the situation with TD 16 requires.

Jeff Masters

Alone again, naturally (ftogrf)
Lonely Seagull, as a storm associated with TD 16 is approaching.
Alone again, naturally

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Quoting NRAamy:
Carolinas!! Carolinas!!!


;)


you're gonna get a spanking...
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Quoting spathy:

I love a double negative.


I don't not like them myself...
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The 18Z GFDL,have this cyclone around 67 knots approaching South Florida this at almost Hurricane strength,I wonder if we can have a surprise? once it crossed Cuba and get into the very warm waters of the florida straits.
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Quoting presslord:
I'm right here...and I'm takin' notes...


Well, *ahem*, I did separate the two...

;-)
Member Since: August 21, 2007 Posts: 0 Comments: 856
1130. Patrap
Quoting NRAamy:
Carolinas!! Carolinas!!!


;)



reow..
Member Since: July 3, 2005 Posts: 414 Comments: 125419
1129. KEEPEROFTHEGATE (Mod)
Quoting presslord:
I'm right here...and I'm takin' notes...
i hope ya don't have too take to many notes
Member Since: July 15, 2006 Posts: 163 Comments: 52096
Quoting weatherguy03:


Everytime I use the word Carolinas I think of you..LOL


as it should be ; )
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1126. jeebsa
Quoting PSLFLCaneVet:


Hey, How are you? Long time between. Sure looks like it. Might even end up with more rain today, than tomorrow.
Yep no worries. keep it to the east will be fine.I might have to sharpen the mower blades.
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Quoting presslord:
I'm right here...and I'm takin' notes...


Everytime I use the word Carolinas I think of you..LOL
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Center of Td 16 reformed

000
WTNT31 KNHC 282339
TCPAT1
BULLETIN
TROPICAL DEPRESSION SIXTEEN INTERMEDIATE ADVISORY NUMBER 2A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL162010
800 PM EDT TUE SEP 28 2010

...CENTER OF THE DEPRESSION RE-FORMS A LITTLE TO THE EAST...


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1121. myway
Quoting GrillinInTheEye:
Just an FYI, even though my children are out of the school system in Florida, they have neglected to take me off there email list and St. Lucie County schools are still open tomorrow. Sorry guys.


Miami Dade, Broward and Palm Beach also have school"s open. Better do your homework kids.
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1120. Patrap
Quoting NCSaint:
Thanks Patrap and Cat5... as saturated as we are right now, ANY surge backs up any possibility of runoff for the extra precip and makes life really bad on the NC coast


Keep the NOAA radio Close and batteries fresh,,as they will have yer Local Action Statements in a timely manner.
Member Since: July 3, 2005 Posts: 414 Comments: 125419
Also, besides the possibility of some Severe Storms moving onshore across SE Florida ahead of Nicole. Could have a pretty good Severe event along the Mid-Atlantic coast as well down the road.
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I'm right here...and I'm takin' notes...
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where's the latest models? shouldnt they be available by now? just wondering...
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Lets see...insane rainfall. Check---5-10" all over eastern NC yesterday and today. More rain? check...another 5-10" expected. Leaves? Check...little color change, let alone falling yet. A little wind? check..40-60mph winds expected. Result? lots of free fire wood!!!!
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1114. NCSaint
Thanks Patrap and Cat5... as saturated as we are right now, ANY surge backs up any possibility of runoff for the extra precip and makes life really bad on the NC coast
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Quoting jeebsa:
Evening Canevet
Just another rain event down here it looks like.


Hey! How are you? Long time between. Sure looks like it. Might even end up with more rain today, than tomorrow.
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1112. Patrap
Quoting Grothar:


Hey, you forgot Ft. Lauderdale!!


They having paid up this last month.

So they get a Nana,Boo-boo Gro
Member Since: July 3, 2005 Posts: 414 Comments: 125419
Quoting CaptnDan142:


Yeah, looks like S. Florida is gonna get a taste of it, but the Carol... um, North Carolina and South Carolina are going to probably see the brunt of the rain. Gonna be ugly whatever way it goes with this mess.


Are you one of the Anti-Carolinas guys!..LOL Where is Presslord??..LOL
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1110. Patrap
Member Since: July 3, 2005 Posts: 414 Comments: 125419
1109. Grothar
Quoting Patrap:
NOAA TD-16




Hey, you forgot Ft. Lauderdale!!
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Quoting bcycsailor:


Well, we're up north right now enjoying the fall regalia, but all of our friends and neighbors are lovin' the lower temps/humidity down there. Looks to be a huge amount of rain for some though. Sheesh!


Yeah, looks like S. Florida is gonna get a taste of it, but the Carol... um, North Carolina and South Carolina are going to probably see the brunt of the rain. Gonna be ugly whatever way it goes with this mess.
Member Since: August 21, 2007 Posts: 0 Comments: 856
1105. Patrap
Wilmington, NC WFO - Visible Loop
Member Since: July 3, 2005 Posts: 414 Comments: 125419
1104. jeebsa
Quoting PSLFLCaneVet:


Hi. So far, since it's sheared and right-loaded, not more than blustery winds with some showers. The obligatory nod to, "if things don't change unexpectedly".
Evening Canevet
Just another rain event down here it looks like.
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Quoting cat5hurricane:
As much as I hate to agree, I'm going to have to. We're still feeling the effects of the front this evening. It's gonna get a lot worse though...


Didnt realize that JB thinks the same. I dont listen to nor like the guy..LOL
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1100. maeko
Quoting weatherguy03:
I will tell everyone this, I believe the affects from Nicole will be worse for the Carolinas then Florida.


the local authorities here in Charleston, SC seem to agree and have been aligning resources.
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Quoting CaptnDan142:


Evenin'

There was some discussion earlier about the westward trend - seemed to make sense. They were talking about the front pulling back.

Personally, I could stand to have it remain right where it is for a while. This low humidity and cool temp thing is kinda nice. Haven't run the AC in over 24 hours now.


Well, we're up north right now enjoying the fall regalia, but all of our friends and neighbors are lovin' the lower temps/humidity down there. Looks to be a huge amount of rain for some though. Sheesh!
Member Since: June 24, 2010 Posts: 0 Comments: 96
1096. NCSaint
Quoting Patrap:
NOAA TD-16




That track sucks for us in coastal NC. On top of the 8+ inches we got yesterday, we get to look forward to another 8+ inches when Nicole strolls by. Anyone have any estimates on potential storm surges for our south-facing beaches and inlets?
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1094. Patrap
Member Since: July 3, 2005 Posts: 414 Comments: 125419
Just an FYI, even though my children are out of the school system in Florida, they have neglected to take me off there email list and St. Lucie County schools are still open tomorrow. Sorry guys.
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Quoting weatherguy03:
I will tell everyone this, I believe the affects from Nicole will be worse for the Carolinas then Florida.


And possibly up along the Mid-Atlantic coastline Northward.
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I will tell everyone this, I believe the affects from Nicole will be worse for the Carolinas then Florida.
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1089. Patrap
NOAA TD-16


Member Since: July 3, 2005 Posts: 414 Comments: 125419
TropicalDepression16's center had reformed (7.5degrees east of) EastSouthEastward
from its previous position

Invest96L : NHC-ATCF
27Sep 12pmGMT - - 18.5n85.5w - - 25knots -- 1003mb - - NHC-ATCF
27Sep 06pmGMT - - 19.0n84.7w - - 25knots -- 1003mb - - NHC-ATCF
28Sep 12amGMT - - 19.4n84.1w - - 25knots -- 1003mb - - NHC-ATCF
28Sep 06amGMT - - 19.8n83.5w - - 30knots -- 1003mb - - NHC-ATCF
28Sep 12pmGMT - - 20.4n83.0w - - 30knots -- 1001mb - - NHC-ATCF
25knots=~28.8mph=46.3km/h __ 30knots=~34.5mph=~55.6km/h
96L becomes TD.16
28Sep 03pmGMT - - 20.6n82.5w - - 35mph - - - 1001mb - - NHC.Adv.#1
28Sep 06pmGMT - - 20.9n82.5w - - 35mph - - - 1000mb - - #1A
28Sep 09pmGMT - - 21.5n82.4w - - 35mph - - - - 999mb - - #2
29Sep 12amGMT - - 21.4n82.0w - - 35mph - - - - 997mb - - #2A
35mph=~56.4km/h

Copy &paste 18.5n85.5w, 19.0n84.7w, 19.4n84.1w, 19.8n83.5w, 20.4n83.0w-20.6n82.5w, 20.6n82.5w-20.9n82.5w, 20.9n82.5w-21.5n82.4w, 21.5n82.4w-21.4n82.0w, ctm, hav, pot into the GreatCircleMapper for a look at the last 12*hours.
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1087. beell
Call it what it is. Not a regular feature of the ATL Basin Season, but...

Monsoon Depression:

The term has gained ascendancy in use to refer to a broad tropical cyclonic circulation characterized by 1) its large size, where the outermost closed isobar may have a diameter on the order of 600 n mi (1000 km); 2) a loosely organized cluster of deep convective elements, which may form an elongated band of deep convection in the east semicircle; 3) a low- level wind distribution that features a 100 n mi (200 km) diameter light-wind core, which may be surrounded by a band of gales or contain a highly asymmetric wind field; and 4) a lack of a distinct cloud system center. Most monsoon depressions that develop in the western North Pacific eventually acquire persistent central convection and accelerated core winds, marking their transitions into conventional tropical cyclones...

...it has a similar structure as an Atlantic tropical depression, except its origin is within the monsoon trough, it is usually larger and it is strongest above the surface...


Link
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Quoting bcycsailor:



Personally, I prefer the models developed through "squirrel-casting" but the method remains untested for some reason :)

I'm wondering with the western jog in the track, if Pinellas County is just going to get squalls out of this system or if we should get that bimini and foresail down below...hmmm.

Good evening btw.


Evenin'

There was some discussion earlier about the westward trend - seemed to make sense. They were talking about the front pulling back.

Personally, I could stand to have it remain right where it is for a while. This low humidity and cool temp thing is kinda nice. Haven't run the AC in over 24 hours now.
Member Since: August 21, 2007 Posts: 0 Comments: 856
Quoting Hoff511:
Hey PSL! What do you expect for us? (in PSL)


Hi. So far, since it's sheared and right-loaded, not more than blustery winds with some showers. The obligatory nod to, "if things don't change unexpectedly".
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.