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 nash28:
Still a little stymied as to how the NHC shifted the track further east on the 5pm as opposed to west.....

UKMET?? Need I say any more? They can't ignore the 18z..


they did not shift it east

the 11am track was right on the coast of Florida, the 5pm track was to the West of Miami and Ft Lauderdale
Member Since: March 10, 2010 Posts: 1 Comments: 7592
Quoting A4Guy:
wouldn't be surprised to see TD16 degenearte into an open wave....the COC looks very poorly defined, and when it starts moving into the shear from the front...could easily rip it open. Earlier today, it seemed as though things were tightening up...but really nothing impressive is going on...at this point. who knows what tonight might bring.


A moderate TS
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Quoting weatherman12345:

do you think there is a possible center relocation
Quoting AllStar17:
Levi - Any thoughts on a possible center SW of Jamaica?


Not SW of Jamaica. There is the possibility of a weak competing mid-level center near 18N, 83.5W, but the circulation in general is very broad. There is a massive dimple of low pressure in the NW Caribbean right now illustrating a ton of heat, but it is not bundled. It is very spread out right now and that's why this system would require a good chunk of time to become a very formidable storm.
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Capt....thank you for validating my credentials...

;)
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Quoting Levi32:
A buoy south of TD #16's center is reporting a pressure of 997mb.
Pressure @ Grand Cayman is 997 mb too.
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Good evening everyone. Weather station here in Jamaica reads 1002 mb and we've got 1.53 inches of rain since midnight.
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527. bwi
Here's earlier data from that buoy south of the Caymans at 17, 81.5. Latest pressure is 1000mb.

09 28 3:50 pm W 11.0 14.0 2.3 8 5.4 - 1000.9 -2.4 25.6 29.2 24.8 - - -
09 28 2:50 pm W 9.0 11.0 2.5 8 5.5 - 1001.8 -2.0 25.9 29.2 24.9 - - -
09 28 1:50 pm SW 12.0 15.0 2.5 7 5.5 - 1002.1 -2.2 28.1 29.2 24.9 - - -
09 28 12:50 pm SW 13.0 15.0 2.6 8 5.6 - 1003.3 -0.7 28.6 29.3 24.7 - - -
09 28 11:50 am SSW 13.0 16.0 2.6 8 5.5 - 1003.8 - 28.7 29.3 24.3 - - -
09 28 10:50 am SSW 14.0 16.0 2.7 8 5.7 - 1004.3 - 28.8 29.3 24.4 - - -
09 28 9:50 am SSW 13.0 15.0 3.0 7 5.8 - 1004.0 - 28.9 29.3 24.8 - - -
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Vorticity has consolidated from yesterday

Link
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525. A4Guy
wouldn't be surprised to see TD16 degenearte into an open wave....the COC looks very poorly defined, and when it starts moving into the shear from the front...could easily rip it open. Earlier today, it seemed as though things were tightening up...but really nothing impressive is going on...at this point. who knows what tonight might bring.
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Quoting nash28:
Still a little stymied as to how the NHC shifted the track further east on the 5pm as opposed to west.....

UKMET?? Need I say any more? They can't ignore the 18z..


The shield around the Tampa area.....lol
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Gotta go get plywood. I'm in the sammywammy cone!
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Tornado Warning
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
534 PM EDT TUE SEP 28 2010

FLC097-282200-
/O.CON.KMLB.TO.W.0033.000000T0000Z-100928T2200Z/
OSCEOLA-
534 PM EDT TUE SEP 28 2010

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM EDT FOR CENTRAL
OSCEOLA COUNTY...

AT 531 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO. THIS TORNADO WAS LOCATED NEAR LAKE
MARIAN...MOVING NORTH AT 30 MPH AND APPROACHING THE FLORIDA
TURNPIKE.

THE TORNADO WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS OF THE
INDICATED COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL MAY OBSCURE THIS TORNADO.
THE SAFEST PLACE TO BE DURING A TORNADO IS IN A STRONG BUILDING ON
THE LOWEST FLOOR...IN AN INTERIOR ROOM SUCH AS A BATHROOM OR CLOSET.
KEEP AWAY FROM WINDOWS. GET UNDER A WORKBENCH OR OTHER PIECE OF
STURDY FURNITURE. USE BLANKETS OR PILLOWS TO COVER YOUR BODY.

&&

LAT...LON 2804 8100 2802 8100 2776 8101 2784 8125
2801 8127
TIME...MOT...LOC 2133Z 178DEG 27KT 2789 8113

$$


KELLY

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997.7mb here in WB Grand Cayman
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Still a little stymied as to how the NHC shifted the track further east on the 5pm as opposed to west.....

UKMET?? Need I say any more? They can't ignore the 18z..
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Levi - Any thoughts on a possible center SW of Jamaica?
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Quoting Levi32:
A buoy south of TD #16's center is reporting a pressure of 997mb.


its relocating to the south..

were the highest convergence is located
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting futuremet:


I doubt Nicole will look that good.


Yeah. The upper-level environment isn't the only thing that is against it.

There's also the amount of time until it becomes extra-tropical.

UKM



GFS

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Quoting CaptnDan142:


Not random at all. It was by request.
What other blog do you know of that has a purple hippo that takes requests?


This is the only one in the universe I'd bet.
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Agreed Kman
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way to go out on a limb there :-P
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I agree with you on this scenario. Let's wait and see...

Quoting leo305:
looks like the LLC is falling apart.. and being sucked into the developing center south east of there...

which means....

IF IT DOES re develop to the south the system may have MUCH more favorable conditions to develop over near 90 degree waters..
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The problem with a system like this is it could turn like Bonnie, which was really the same as our afternoon thunderstorms, or it could be a mess like Katrina or Irene. Both of these last storms brought much more weather than anyone expected.

Seems to me they are assuming that it won't be much weather. If that changes, there are going to be a lot of people on the road, and it will be a real mess.
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503. DDR
Hurricanecat5
You wanted rain....
Now you got it,hope you don't get too much flood
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A buoy south of TD #16's center is reporting a pressure of 997mb.
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Quoting NRAamy:
Not random...check out the previous page...

-2 points for not keeping up with the rest of us.....

Back to the weather....


D'oh, my apologies.
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Quoting Saltydogbwi1:


I believe the aircraft jetwash interferes with this station as it is at the airport there have been many questionable wind speed readings over the last year


Even so the barometer is correct and right now 997.6 is where we are at.
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Great.. Can't wait to have water restrictions again.

Quoting seflagamma:
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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We do not need monsoon rain here in Charleston. Market St. downtown floods when someone sweats heavily.
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Quoting futuremet:


I doubt Nicole will look that good.


Now your just over-exagerrating.

Plus, it doesn't really matter how it looks. If it has the winds...There you go.
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Quoting futuremet:


Say that to Jasonxxxxxx


lol

About 50% of my ignore list consist of the JFV and Jason handles.
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Strange, I see the system as quite organised.
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Quoting kmanislander:


Not sure but 80 + winds would have been a long time ago LOL


I believe the aircraft jetwash interferes with this station as it is at the airport there have been many questionable wind speed readings over the last year
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Quoting Stormchaser2007:
I remember the day that Barry formed.

Was a crazy day on here.



I doubt Nicole will look that good.
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490. mbjjm
Important section of the NHC 5pm edt discussion

AIR FORCE HURRICANE HUNTERS FOUND THAT THE LOW-LEVEL CENTER
CONSISTED OF A BROAD AREA OF LIGHT WINDS AND NEARLY UNIFORM
PRESSURE. INDEED...WINDS WERE 20 KT OR LESS WITHIN 100 N MI OR
MORE OF THE CENTER. CLEARLY...THIS IS NOT A CLASSICAL TROPICAL
CYCLONE AND THE MAXIMUM WINDS ARE LOCATED SOME 200 N MI SOUTHEAST
OF THE CENTER. OBSERVATIONS FROM NOAA DATA BUOY 42057 FROM EARLY
THIS MORNING AND ASCAT DATA FROM AROUND 1500 UTC SUGGESTED THAT THE
SYSTEM MAY HAVE BEEN A MARGINAL TROPICAL STORM EARLIER TODAY. THERE
IS SOME QUESTION...HOWEVER...AS TO WHETHER THOSE WINDS WERE
REPRESENTATIVE OF THE CYCLONE SCALE. IN ANY EVENT...RECENT
HURRICANE HUNTER DATA SHOWS NO EVIDENCE OF TROPICAL STORM
FORCE WINDS AT THIS TIME. THE SATELLITE PRESENTATION IS NOT VERY
IMPRESSIVE...WITH RAGGED-LOOKING BANDING FEATURES AND VERY LITTLE
DEEP CONVECTION NEAR THE CENTER. SOUTH-SOUTHWESTERLY VERTICAL
SHEAR ASSOCIATED WITH A LARGE MID- TO UPPER-LEVEL TROUGH MOVING
OVER THE SOUTHEASTERN UNITED STATES...ALONG WITH THE CURRENT
STRUCTURE OF THE CYCLONE...SHOULD LIMIT INTENSIFICATION OVER THE
NEXT DAY OR SO. THE OFFICIAL INTENSITY FORECAST IS A LITTLE HIGHER
THAN THE LATEST STATISTICAL/DYNAMICAL LGEM PREDICTION. GLOBAL
MODEL GUIDANCE INDICATES THAT THE SYSTEM SHOULD MERGE WITH A FRONT
AND BECOME EXTRATROPICAL IN ABOUT 36 TO 48 HOURS. AFTER THAT...THE
MODELS ALSO SHOW WHAT APPEARS TO BE A NEW BAROCLINIC DEVELOPMENT TO
THE NORTH REPLACING THE FORMER TROPICAL CYCLONE...SO DISSIPATION IS
EXPECTED BY 72 HOURS.


Member Since: August 23, 2010 Posts: 0 Comments: 310
I remember the day that Barry formed.

Was a crazy day on here.

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Quoting Stormchaser2007:
Rules of the Road

5)Do not circumvent administrative action by creating new users, etc.


Say that to Jasonxxxxxx
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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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