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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Recon found winds of 51mph
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Also our local Water Management for SE Florida says they have been drawing down water in our canals for 24 hours now.. I did notice while I was out this afternoon that the water level had dropped some from yesterday in the canals...

so at least we will have some room for some of the flooding.
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Quoting sammywammybamy:
South Florida Water Distirct Opening Flood Gates.


Crap that means it wont rain. IF it does they will continue to drain the water again until we are in a CRISIS situation!
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Quoting leo305:


who is they?


Phil Ferro.
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Quoting cat5hurricane:
Yep...I noticed that.

And the Quantitative Precipitation Forecasts only are a general estimate. I would not be a bit surprised if locally some spots pick up much more than that.


In fact there are areas here in Brevard County, FL that have received 6" of rainfall... and the bulk of the activity has not even arrived
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638
fxus62 kchs 282035
afdchs


Area forecast discussion
National Weather Service Charleston SC
435 PM EDT Tuesday Sep 28 2010


Synopsis...
a stationary front over the Atlantic will shift west closer to
the coast tonight. A complex low pressure system will move up the
southeast United States coast through Thursday. High pressure
will build in from the northwest late in the week and over the
weekend.


&&


Near term /until 6 am Wednesday morning/...
a strong shortwave will continue to drop southeast into the Tennessee
Valley tonight and become cut off from the rest of the flow.
Meanwhile...along the lingering stationary front offshore...an
inverted surface trough of low pressure will develop. Moisture
will continue to increase from east to west overnight along with
isentropic ascent. The forecast area will also become situated in
a favorable region for ascent of a strengthening upper level jet.
Showers/isolated thunderstorms will become likely after midnight
along the coast...spreading farther inland toward Interstate 95
toward daybreak. Lows will be coolest /around 60/ across far
interior areas from Allendale southwest toward Millen while
remaining in the lower to middle 70s along the coast.


&&


Short term /6 am Wednesday morning through Friday/...
a deepening cutoff low over the lower MS valley and strong upper
level jet divergence over the eastern United States will increase
frontogenesis along the SC/Georgia coasts on Wednesday. An impressive southerly
flow will be in place through the entire troposphere by noon
Wednesday with model forecast precipitable water/S increasing to an unseasonable 2.25"
across southern SC. Tropical depression 16 is expected to become
extratropical and merge with the baroclinic zone along the coast
Wednesday night. The exact track of the coastal low will have a
large impact on the band of heaviest rainfall. The 12z Gem and GFS
both seemed fairly reasonable with their track of the coastal low in
relation to the Upper Cutoff but seemed fast. Fortunately the 12z
European model (ecmwf) came in with a very similar track to the aforementioned models
but with a slower speed. We have a period of categorical probability of precipitation across
the eastern half of the area Wednesday through Wednesday evening with likely
probability of precipitation late Wednesday night in the eastern areas. The forecast for the
western half of our area is more tricky because some guidance shows
almost no precipitation while others show scattered to numerous
showers. We have some rain chances in even farthest western zones
but have a sharp pop gradient across the SC/Georgia border. Confined the
thunderstorm possibilities to coastal waters and immediate coastal
zones for most of the period where guidance indicates the negative
lifted indices and some surface based instability. See the hydrology
section for information on the Flash Flood Watch.


Precipitation should be tapering off Thursday morning with partial clearing by
afternoon. Temperatures will be close to normal.

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Looking at the GFS 12z run, we may get our W-named storm by mid-to-late October, and our first lake-effect snowfalls in S. Ontario by October 3 and Oct. 13.
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Quoting Patrap:


Starting to refire some red cloud tops in the last frame and also finally some light blue pops north of the circulation.
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Quoting seflagamma:
They are saying if this storm does not "tighten up" most of the wind and even heavy rain will be far east of us here in South Florida.


who's they?
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374. GoWVU
Ok folks what does it look like for us here in Charleston SC?
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Cancel comment 338. But i still think there is more than one center but they had to make a choice, they got the plane, the plane, boss.
Member Since: August 18, 2008 Posts: 0 Comments: 3112
Quoting clwstmchasr:


Really shows that this is not a typical cyclone that we are use to seeing in our part of the world.


Conditions at our international airport
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WHOA!

20:56:30Z 17.967N 79.117W 977.9 mb
(~ 28.88 inHg) 204 meters
(~ 669 feet) 1001.5 mb
(~ 29.57 inHg) - From 224° at 21 knots
(From the SW at ~ 24.1 mph) 19.1°C*
(~ 66.4°F*) -* 26 knots
(~ 29.9 mph) 55 knots
(~ 63.2 mph) 33 mm/hr
(~ 1.30 in/hr) 44.4 knots (~ 51.1 mph)
Tropical Storm 211.5%
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Atlantic 26C Thermocline

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david brenard just said.. its more likely that NICOLE moves east of SOUTH FLORIDA and that the heaviest weather will be well off shore..

...

I guess he ignored the models which is shocking for him.. based on what I've seen from him..
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Quoting kmanislander:
I find it somewhat amusing that the surface pressure at Grand Cayman is lower than the pressure where the center of TD16 is. Doesn't make a lot of sense to me.
Doesn't seem to make sense. Perhaps it's indicative of just how broad the low pressure area is. And deep as well.
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They are saying if this storm does not "tighten up" most of the wind and even heavy rain will be far east of us here in South Florida.
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Quoting MarathonZiggy:
After reading the 5PM discussion, I'll stand on my earlier reasoning that the trough will preclude this TC from amounting to anything but a rain maker for the Bahama's & a little windier for S Fla in the near future. Post Tropical is a whole different story though.

Wow...is this a trough over the Eastern United States??.......:)
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I really think the center may try to reform SW of Jamaica.  Winds stronger and convection continues to flare up.
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Local News official words is Public Schools are set as of now to be Open tomorrow.


and we have Flood Watch,
and TS Warnings.

still a TD not a TS yet.

this is not going to be a big event for us I do not think...
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New cone didn't shift west barely at all... about a hair. It got more narrow in the long-term.

Link
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Outerbanks are going to get the worst of this mess.
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Quoting KanKunKid:


So what's it like to sit at the adults table? Nothin' but love? I don't know when you last sat at "The adults table" at Thanksgiving, but it wasn't an exchange of info, learning about weather or the like was it? I always thought the kids had more fun and didn't have to listen to the relatives who liked to hear themselves talk. The only thing I learned was not helpful in the real world.

I'm not sticking up for the troll, and I'm not picking on you. But is it possible to have fun AND learn about weather?


+10
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I'll fix it, Cosmic.....

:)
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Link

sorry image not working on mozilla.
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000
WTNT31 KNHC 282052
TCPAT1
BULLETIN
TROPICAL DEPRESSION SIXTEEN ADVISORY NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL162010
500 PM EDT TUE SEP 28 2010

...TROPICAL DEPRESSION HAS CHANGED LITTLE IN INTENSITY SO FAR...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...21.5N 82.4W
ABOUT 115 MI...190 KM S OF HAVANA CUBA
ABOUT 330 MI...530 KM SSW OF MIAMI FLORIDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HR
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 10 MPH...17 KM/HR
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* THE CAYMAN ISLANDS
* THE PROVINCES OF CUBA FROM MATANZAS EASTWARD TO CIEGO DE AVILA
* THE NORTHWESTERN AND CENTRAL BAHAMAS
* JUPITER INLET SOUTHWARD TO EAST CAPE SABLE AND FLORIDA BAY
* THE FLORIDA KEYS

A TROPICAL STORM WATCH IN IN EFFECT FOR...
* NORTH OF JUPITER INLET TO SEBASTIAN INLET FLORIDA
* NORTH OF EAST CAPE SABLE TO CHOKOLOSKEE FLORIDA

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE
THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.
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I find it somewhat amusing that the surface pressure at Grand Cayman is lower than the pressure where the center of TD16 is. Doesn't make a lot of sense to me.
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After reading the 5PM discussion, I'll stand on my earlier reasoning that the trough will preclude this TC from amounting to anything but a rain maker for the Bahama's & a little windier for S Fla in the near future.  Post Tropical is a whole different story though.

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Notice this was added at 5 p.m.

TORNADOES...ISOLATED TORNADOES ARE POSSIBLE OVER SOUTHEASTERN FLORIDA AND THE FLORIDA KEYS THROUGH TONIGHT.
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Quoting TreasureCoastFl:

Oh? My apologies. I am not nearly as knowledgeable as any of you with this stuff.


LOL..Hey TC..ya gotta be careful about what ya say and who ya say it to in here....otherwise ya might just get spanked. Must be the barometric pressure causing all the irritability..lol ;)
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20:43:30Z 17.717N 79.333W 975.8 mb
(~ 28.82 inHg) 223 meters
(~ 732 feet) 1000.6 mb
(~ 29.55 inHg) - From 218° at 35 knots
(From the SW at ~ 40.2 mph) 26.0°C
(~ 78.8°F) 22.7°C
(~ 72.9°F) 36 knots
(~ 41.4 mph)

20:44:00Z 17.700N 79.300W 976.8 mb
(~ 28.84 inHg) 213 meters
(~ 699 feet) 1000.6 mb
(~ 29.55 inHg) - From 219° at 35 knots
(From the SW at ~ 40.2 mph) 26.0°C
(~ 78.8°F) 22.8°C
(~ 73.0°F) 36 knots
(~ 41.4 mph)
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There is more than one center maybe that's the delay on the vortex message.
Member Since: August 18, 2008 Posts: 0 Comments: 3112
New discussion just released by NHC.
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Notice the piece of energy off the west coast of florida, that may be the reason why the models have shifted left and will draw it more North into the SW coast of florida.
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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.

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