Caribbean disurbance 96L nearly a depression; hottest day ever in Los Angeles

By: Dr. Jeff Masters , 1:54 PM GMT on September 28, 2010

Share this Blog
4
+

Pressures continue to fall over the Western Caribbean this morning as a strong tropical disturbance (96L) organizes. Surface observations suggest that 96L has a large circulation covering most of the Western Caribbean, as evidenced by winds out of the southwest sustained at 29 - 34 mph observed at Buoy 42057 to the southeast of 96L's center this morning. Rotation of 96L 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 are bringing torrential rains to the Cayman Islands, Jamaica, Cuba, and Honduras. A Personal Weather Station in George Town on Grand Cayman Island has picked up 3.64" of rain in the twelve hours ending at 8am this morning. 96L is not the typical sort of disturbance one sees in the Atlantic, since it is much larger than normal. What has happened is that 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). 96L 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 a regular tropical storms, if given enough time over water to develop a tight, closed circulation. The Hurricane Hunters are scheduled to fly into 96L this afternoon near 2pm EDT to see if it has become a tropical depression.


Figure 1. Morning radar image of 96L. Image credit: Cuban Institute of Meteorology.

Forecast for 96L
Because 96L is so large and lacks a well-defined surface circulation, it will take more time than a typical disturbance for it to spin up into a strong tropical storm. Given that the steering currents are expected to pull 96L 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 55 mph tropical storm for Florida. I think the top winds in Southeast Florida are likely to be in the 30 - 45 mph range on Wednesday. By the time 96L makes landfall in North Carolina or South Carolina on Thursday morning or afternoon, it could be as strong as a 55 - 65 mph tropical storm, but I think it is only 20% likely that 96L will make it to hurricane strength on Thursday. The primary danger from the storm is heavy rainfall. A potent upper-level low and stationary front over the U.S. East Coast have been bringing moist, tropical air from the Caribbean northwards over the past few days, bringing heavy rains that have saturated the soils. 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 96L 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.


Figure 2. Radar-estimated precipitation since Saturday for the North Carolina/South Carolina border region. Widespread rain amounts of 5 - 10 inches have occurred.


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

Elsewhere in the tropics
Once 96L 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 late this week or early next week. The other models are not showing this, but do predict a continuation of the disturbed weather pattern over the Western Caribbean. A second disturbance, if it develops, would be subject to similar steering currents, and may also move northwards across Cuba, Florida, and the Bahamas, then up the U.S. East Coast. This second disturbance might be more dangerous, since it would be dumping heavy rains on regions already drenched by 96L.

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 Beverly Hills 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 96L requires.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 997 - 947

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21Blog Index

Multiplatform Tropical Cyclone Surface Winds Analysis (MTCSWA)

AL162010 SIXTEEN for Run: 2010-09-28 18Z


Member Since: Posts: Comments:
Quoting BLee2333:
I haven't seen winds that support a TS designation.


that is because they have yet to go to the convection to the east of the center
Member Since: Posts: Comments:
Quoting Hurricanes101:


they have yet to go to the convection east of the center kman, they are still trying to fix the COC location


They should look closer to us. Pressure at our airport now 998.6 mb and still falling.
Member Since: Posts: Comments:
I haven't seen winds that support a TS designation.
Member Since: January 6, 2009 Posts: 0 Comments: 217
Quoting presslord:


if you work off island you may very well not be going to work thursday...


Work on Kiawah, should be an interesting drive in.
Member Since: Posts: Comments:
Quoting Bordonaro:

Well, welcome Tropical Storm Nicole, welcome to the 2010 Atlantic Hurricane Season family. You make number 14 :O), please be kind, bring beneficial rains only.

New record 8 TC's in the month of September, we are now at:
14 TC's, 7 hurricanes and 5 majors so far and the party is not over yet!


It is not a TS yet, atcf jumped the gun

they changed it back to a TD a few minutes later
Member Since: Posts: Comments:
Interesting westerly shift in latest models...wonder if NHC will follow suit at 5pm?
Thoughts?
Member Since: Posts: Comments:
Quoting CyclonicVoyage:


I can't speak for others but, I surely am. HWRF and GFDL keep trading Hurricanes back and forth past 2 days.


Right, which is exactly why people shouldn't be brushing these models off. In fact, I've always known the GFDL/HWRF to be reliable models.
Member Since: Posts: Comments:
Quoting kmanislander:
It has the pressure of a TS but does not have the winds to go with it.

Very odd system.


they have yet to go to the convection east of the center kman, they are still trying to fix the COC location
Member Since: Posts: Comments:
Thats due to the Gyres size..takes more time to rotate as itsa Big sized system.

Member Since: Posts: Comments:
I know this isn't a typical Atlantic depression and more like a Pacific storm, but doesn't 999mb pressure typically translate into a moderate tropical storm?
Member Since: Posts: Comments:
Quoting reedzone:


AL162010092818BEST0212N829W351000TS

Will be upgraded at 5 p.m.

Well, corrected, still TD 16..

At 7 TC's in the month of September, we are now at:

13 TC's, 7 hurricanes and 5 majors so far and the party is not over yet!

Wind shear should keep TD 16 in check!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting kmanislander:
It has the pressure of a TS but does not have the winds to go with it.

Very odd system.


Reminds me of Alex.
Member Since: Posts: Comments:
20.933N 83.400W 998.9 mb still not a fixed COC
Member Since: January 6, 2009 Posts: 0 Comments: 217
Quoting CaptnDan142:


Confusion. It's what happens when people jump the gun.


No one jumped the gun, atcf site is the official word of NOAA and the NHC, they upgraded it to a TS

THEY jumped the gun then, not us
Member Since: Posts: Comments:
It has the pressure of a TS but does not have the winds to go with it.

Very odd system.
Member Since: Posts: Comments:
based on radar I think the center is closer to the isle of youth than they have it at 2pm, meaning further west
Member Since: Posts: Comments:
Quoting jholmestyle:
Winnsboro, might be taking a boat to work on thursday.


if you work off island you may very well not be going to work thursday...
Member Since: Posts: Comments:
Quoting tropicfreak:


I though ATCF changed it back to TD. This is confusing me.


Confusion. It's what happens when people jump the gun.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Winnsboro, might be taking a boat to work on thursday.
Member Since: Posts: Comments:
I just saw the HH take off from Owen Roberts airport (GCM) around 1:55pm local time.
Member Since: Posts: Comments:
Highly unlikely however, possible. I think it will be a high end TS. No difference from a low end CAT 1 if you ask me.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Member Since: Posts: Comments:
Quoting reedzone:


AL162010092818BEST0212N829W351000TS

Will be upgraded at 5 p.m.


they changed it back a few minutes later to a TD
Member Since: Posts: Comments:
Quoting TreasureCoastFl:
From local weatherman : "ATFC indicates that Tropical Depression Sixteen has been upgraded to Tropical Storm Nicole. No official confirmation yet from NHC."


As I mentioned a short while ago, ATCF said it was a tropical storm with 35 knot winds, but then recanted that 20 minutes later and said it was only a 30-knot tropical depression after all.
Member Since: November 8, 2009 Posts: 4 Comments: 13552
Quoting reedzone:


AL162010092818BEST0212N829W351000TS

Will be upgraded at 5 p.m.


I though ATCF changed it back to TD. This is confusing me.
Member Since: Posts: Comments:
Quoting jholmestyle:


We had large branches and a tree go down on Bohicket and Betsy Kerrison pkwy with the rain yesterday. If the models and precip forecast verifies I'm afraid we'll lose alot of grand oaks Thursday.


I'm on Johns Island, too....at Fenwick Hall...
Member Since: Posts: Comments:
Poor old (new?) TD 16, it's already being rip apart by that super deep (& still diggin) trough.

Adios.

Zig in Marathon, Fla
Member Since: Posts: Comments:
Quoting Ron5244:
Why is everyone paying no attention to the latest GFDL run?



I can't speak for others but, I surely am. HWRF and GFDL keep trading Hurricanes back and forth past 2 days.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Quoting Hurricanes101:


I thought the said it was still a TD


AL162010092818BEST0212N829W351000TS

Will be upgraded at 5 p.m.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
Quoting presslord:


not you...it's the track I don't like...


We had large branches and a tree go down on Bohicket and Betsy Kerrison pkwy with the rain yesterday. If the models and precip forecast verifies I'm afraid we'll lose alot of grand oaks Thursday.
Member Since: Posts: Comments:
TD-16 Floater - Rainbow Color Infrared Loop

TFP's are available
Member Since: Posts: Comments:
19:08:00Z 20.733N 83.600W 999.1 mb
Member Since: Posts: Comments:
Quoting Ron5244:
Why is everyone paying no attention to the latest GFDL run?

Wow.
Member Since: Posts: Comments:
Quoting reedzone:
Tropical Storm NIcole slowly organizing, look at the convection north and south of the center.. Getting a bit symmetrical.



I thought the said it was still a TD
Member Since: Posts: Comments:
Quoting Waltanater:
Yes, I noticed that too! Similar to how Wilma(2005) started to organize. The only differences here is that TD16 is going N and is affected by some shear. Wilma went W and had diminishing shear. The pressures were about the same (comparing when Wilma was first a depression) and I surmise that the SST were about the same as well) If that trough is backing up a bit, maybe it won't become subtropical later!?





Member Since: Posts: Comments:
Looks to be tightening up just south of the western tip of Grand Cayman 20.5N 83W
Member Since: January 30, 2010 Posts: 0 Comments: 3259
Member Since: Posts: Comments:
Why is everyone paying no attention to the latest GFDL run?

Member Since: Posts: Comments:
Quoting tropicfreak:


What?? It didn't show up for me before, but I just refreshed the page and whalaa, it appears. What did I do wrong??


not you...it's the track I don't like...
Member Since: Posts: Comments:
Quoting reedzone:
Convection starting to consolidate around the center, this IS organizing at a slow pace.

Yes, I noticed that too! Similar to how Wilma(2005) started to organize. The only differences here is that TD16 is going N and is affected by some shear. Wilma went W and had diminishing shear. The pressures were about the same (comparing when Wilma was first a depression) and I surmise that the SST were about the same as well) If that trough is backing up a bit, maybe it won't become subtropical later!?
Member Since: Posts: Comments:
Tropical Storm NIcole slowly organizing, look at the convection north and south of the center.. Getting a bit symmetrical.

Member Since: July 1, 2008 Posts: 13 Comments: 7396
Complete Update


AOI
AOI AOI AOI

AOI AOI AOI

TS BUSTED FORECAST ALIBI
Member Since: Posts: Comments:
Quoting HurricaneRoman:
oh my god! This reminds me of hurricane Irene (1999)


yes it is starting to look like another Irene...
Member Since: August 29, 2005 Posts: 299 Comments: 40917
Quoting presslord:


Stop it!!


What?? It didn't show up for me before, but I just refreshed the page and whalaa, it appears. What did I do wrong??
Member Since: Posts: Comments:
Quoting chrisdscane:


is that from recon


yes
Member Since: Posts: Comments:
Quoting reedzone:
The REED run is a bit too far east.. hmm, interesting isn't it?

Photobucket


Need more funds for a new super reed computer.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting TOMSEFLA:
were you on the island for ivan?


Who ??
Member Since: Posts: Comments:
Thats a LOTTA Junk to Move N to NE next 48,
Someones gonna get the Bizz big time.

Member Since: Posts: Comments:

Viewing: 997 - 947

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21Blog Index

Top of Page

About

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