Jamaica disturbance getting better organized

By: Dr. Jeff Masters , 8:38 PM GMT on October 14, 2005

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A broad 1005 mb low pressure area centered over the island of Jamaica continues to become better organized. There has been an increase in intensity and areal coverage of the deep convection this afternoon, and some upper-level cirrus clouds moving northwards away from the storm show the beginnings of what may be an upper-level outflow channel starting to develop. An upper level anti-cyclone is beginning to develop on top, and the wind shear continues to drop--down to 5 - 10 knots. This low enough to support continued organization. The presence of Jamaica so close to where the center is trying to form will probably not pose a significant problem for the storm, since Jamaica is a relatively small island.

Global computer models forecast that the shear will continue to decrease over the area Saturday and Sunday, and I believe that a tropical depression is likely by Saturday or Sunday. Steering currents are very weak, and the disturbance is expected to stay in the central or western Caribbean for at least the next five days, which would give ample time for this system to grow into a hurricane.

It bears repeating that the eventual track of any tropical storm or hurricane that forms is impossible to forecast with any reliability, since steering currents are very weak and a some erratic motion is likely. The UKMET and NOGAPS models favor a track towards Honduras and Belize, while the GFS takes the system northeast across Cuba and the Bahamas. The early track models (i.e., BAM, LBAR and VICBAR models) have not been run yet for this system, but I will post them when they become available.

Cape Verdes tropical disturbance
A tropical disturbance about 500 miles southwest of the Cape Verde Islands continues to slowly improve in organization. Visibile satellite imagery and QuikSCAT satellite winds suggest that a surface circulation may be forming here, and some modest upper-level outflow has developed to the north. The system is headed towards an area of low wind shear, which may allow some further development over the next few days as it tracks west-northwest over the open ocean. Tropical storms developing this far east in mid-October are very rarely a threat to the Caribbean or North America.

New England
New England continues to suffer the onslaught of a very wet stream of tropical air from the southeast that has caused nine straight days of rain. The axis of moisture has shifted slightly eastwards today, finally giving New York City a break from the 6 - 8 inches of rain that has fallen the past two days alone. This tropical onslaught will continue moving northeast over the weekend before exiting northern Maine on Sunday.


Figure 2. Lots of rain in the Northeast the past week, but currently just a few areas of major river flooding, in New Jersey.

Katrina's winds revisited
In my last blog entry on this subject, we discussed the Florida Sun-Sentinel article commenting on new findings that indicate Katrina was only a Category 3 hurricane at first landfall near the mouth of the Mississippi, and a Category 1 hurricane over New Orleans. The article was rather imprecise in its use of the Category system for ranking hurricanes, and I interpreted the article to mean that Katrina was a Category 1 at landfall in Mississippi. Upon re-reading the article, I think what they were trying to say was that Katrina had Category 1 force winds over New Orleans, not that the storm itself was a Category 1. As several of you have pointed out, it is pretty difficult to have a hurricane with a 927 mb pressure (Katrina's pressure at landfall in Mississippi) with just Category 1 winds. Katrina was a least a strong Category 2, and perhaps a weak Category 3 hurricane at landfall in Mississippi. While Katrina did have unusualy high winds aloft compared to surface winds (which NHC noted on one of their discussions during the storm), this difference was not enough to make Katrina a Category 1 hurricane at landfall in Mississippi. Sorry for sowing the confusion!

I'll have an update tonight by 10pm if the Jamaica system continues to develop. I'll post my follow-up to the Katrina winds posting I made yesterday when I get it done. This is a complicated subject, and it's taking me a long time to do the write-up, sorry for the delay!

Jeff Masters

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182. Neapolitan
3:08 PM GMT on July 21, 2011
NEW BLOG ENTRY
Member Since: November 8, 2009 Posts: 4 Comments: 13250
181. buckeyefan1
2:01 AM GMT on October 15, 2005
I thought I did, ok maybe a rough day today!! Friday's should be easy!! LOL Buy for now everyone. Have to pick up my Daughter from colorguard (H.S. Football game)
180. HIEXPRESS
1:59 AM GMT on October 15, 2005
Here's a question for you "gurus" out there: In the complete absence of steering currents, with equal sst & pressure all the way around, which way does a Developing tropical cyclone move?
Member Since: October 13, 2005 Posts: 4 Comments: 2155
179. buckeyefan1
1:56 AM GMT on October 15, 2005
good night Finn!!
178. LakeWorthFinn
1:56 AM GMT on October 15, 2005
jeff has new posting
Member Since: October 6, 2005 Posts: 67 Comments: 7198
177. LakeWorthFinn
1:55 AM GMT on October 15, 2005
Ah, ok lefty. K guys and gals, good night, see you later. Thanks for teachings!
Member Since: October 6, 2005 Posts: 67 Comments: 7198
176. buckeyefan1
1:54 AM GMT on October 15, 2005
man I can't even tell left from right LOL! I ment left..geez
175. buckeyefan1
1:52 AM GMT on October 15, 2005
Lake, I was looking at that a little bit ago, thought the same thing, but waiting on the llc to shift. it's still to the right
174. leftyy420
1:51 AM GMT on October 15, 2005
theres a link button and u simply put the link in there and than post the comment
Member Since: August 24, 2005 Posts: 35 Comments: 1987
173. buckeyefan1
1:50 AM GMT on October 15, 2005
I'm guessing that a tornado was never official, so I would think it was a downdraft at that time, with a rotating cloud abserved by doppler


lefty, great minds think alike LOL :)
172. code1
1:50 AM GMT on October 15, 2005
Dr. Master's has a new blog.
Member Since: September 18, 2005 Posts: 66 Comments: 13872
171. LakeWorthFinn
1:50 AM GMT on October 15, 2005
ok thanks lefty
I'm gind to bed soon, but see that the Jamaica blob has swifted eastwards on this loop:
http://www.intellicast.com/Local/USNationalWide.asp?loc=usa&seg=StormCenter&prodgrp=SatelliteImagery&product=CaribbeanLoop&prodnav=none
How do I get a siple link to appear, not the whole URL?
Member Since: October 6, 2005 Posts: 67 Comments: 7198
170. buckeyefan1
1:47 AM GMT on October 15, 2005
That's kinda scarry. Just as long as she stayes away!:)
169. leftyy420
1:45 AM GMT on October 15, 2005
lake, that was a dowbdraft or small microburst. they happen durring t-storms and souns like you were in one.
Member Since: August 24, 2005 Posts: 35 Comments: 1987
168. leftyy420
1:44 AM GMT on October 15, 2005
the ships is less aggressive calling for barely a hurricane in 3-4 days.

also the gfs still does not foprm the system. currently only the ukmet and canadian show any sig development of the 98l system
Member Since: August 24, 2005 Posts: 35 Comments: 1987
167. leftyy420
1:41 AM GMT on October 15, 2005
latest gfdl run on 98l brings her to cat 4 almost cat 5 strength in 3-4 days.

Link
Member Since: August 24, 2005 Posts: 35 Comments: 1987
166. LakeWorthFinn
1:37 AM GMT on October 15, 2005
No tornado formed, but 64 m gusts? Can they just happen every once in a while? A few trees came down around the area.
Member Since: October 6, 2005 Posts: 67 Comments: 7198
165. buckeyefan1
1:27 AM GMT on October 15, 2005
Nope, don't want anything bad for anyone. Just want to witness history
164. palmettobug53
1:26 AM GMT on October 15, 2005
code1, you are right. It is morbidly fascinating to watch one, as long as it ain't "here". It's always good to remember to be careful what you wish for.
Member Since: October 7, 2005 Posts: 229 Comments: 24573
163. paweatherfan
1:25 AM GMT on October 15, 2005
Just checked the latest infared in carribean and the blob has some real deep convection firing, interesting to see what happens here.
162. code1
1:23 AM GMT on October 15, 2005
paweatherfan, scary clips! For all of you wishing for Wilma, please add wishing that it stays a fish storm! I've noticed that most of you wishing for it, are not from FL. In no way do I mean any disrespect (I enjoy reading all blogs), but, I lived through Ivan and wasn't sure that I would around 2:30 that morning. Ivan in no way compared to the intensity of Charley, and it was bad enough. It got more air play because it was a much larger storm.
Member Since: September 18, 2005 Posts: 66 Comments: 13872
161. buckeyefan1
1:23 AM GMT on October 15, 2005
me too! observed..
160. buckeyefan1
1:22 AM GMT on October 15, 2005
I'm guessing that a tornado was never official, so I would think it was a downdraft at that time, with a rotating cloud abserved by doppler
159. LakeWorthFinn
1:20 AM GMT on October 15, 2005
Katrina, my typo is also bad today :)
Member Since: October 6, 2005 Posts: 67 Comments: 7198
158. turtlehurricane
1:16 AM GMT on October 15, 2005
i hav updated my blog
Member Since: July 22, 2005 Posts: 227 Comments: 469
157. LakeWorthFinn
1:16 AM GMT on October 15, 2005
There's a question that has been bothering for a while...
I was in Boynton Beach, home alone, and saw in the weather channel a sudden black image with the peeep-peeep sound, and a tornado warning. There was (to my knowledge) no prior forecast for such a thing, just rain and winds. Then the day after I read that 64 mile gusts had been recorded. What was THAT? (It was maybe a week or 10 days before Kastrina hit)
Member Since: October 6, 2005 Posts: 67 Comments: 7198
156. buckeyefan1
1:15 AM GMT on October 15, 2005
I stayed up all night and watched this storm. I was kinda worried that it would go more north, you never know, sometimes they have a mind of their own
155. tornadoty
1:11 AM GMT on October 15, 2005
Those are some awesome pics paweatherfan.
154. palmettobug53
1:08 AM GMT on October 15, 2005
That was wild!
Member Since: October 7, 2005 Posts: 229 Comments: 24573
153. buckeyefan1
1:07 AM GMT on October 15, 2005
you wouldn't catch me there! that is one brave person!
152. paweatherfan
1:03 AM GMT on October 15, 2005
I just watched the race trac station again, and again I am in awe! thats just vicious
151. buckeyefan1
12:56 AM GMT on October 15, 2005
fan, those are some wicked pics!
150. paweatherfan
12:50 AM GMT on October 15, 2005
With all the Charlie chat thought I might add this!! It still is one of the best clips I've seen.
Link
149. buckeyefan1
12:45 AM GMT on October 15, 2005
That's me opinion too, but I have argued with others that disagree, that was for them :)
148. tornadoty
12:42 AM GMT on October 15, 2005
Vince was 100% tropical when in was classified as a hurricane. The convection was concentrated near the center, and there was a well-defined eye.
147. buckeyefan1
12:38 AM GMT on October 15, 2005
Tornadoty, I agree.
88, Yes there warm enough temps in the gulf, look at just at Vince pretty cool water, but still classified "hurricane" although, some might say it was sub-tropical
146. tornadoty
12:31 AM GMT on October 15, 2005
Hi, I'm back.

The convection has been impressive, and I think I might be seeing evidence of the LLC on the infrared satellite loop. I think depression no later than 11:00 AM tomorrow.
145. 8888888889gg
12:20 AM GMT on October 15, 2005
is the gulf water too cold to have any more hurricane this year or is the water in the gulf back up to 80 to 90 water in the gulf any one have this ? for me let me no thank you
144. buckeyefan1
12:14 AM GMT on October 15, 2005
pretty nice outflow on the NE side too
143. buckeyefan1
12:13 AM GMT on October 15, 2005
I'm back, love children! LOL
Thanks weatherboy! It's definately there. I believe (hopeful maybe) that this will be a depression at the 11:00 advisery. But lately they haven't said anything until recon has arrived.
142. theboldman
12:12 AM GMT on October 15, 2005
hey wannabe you on hows my laughting buddy lol
Member Since: September 8, 2005 Posts: 25 Comments: 2
141. weatherboyfsu
12:02 AM GMT on October 15, 2005
Buckeye....go to the colorado link on here....and click on tropics and the box over cuba.....it has a close up loop...you can see the spider legs (low level bands) creeping around the perifery of jamaica..........
Member Since: July 17, 2005 Posts: 0 Comments: 1025
140. palmettobug53
12:01 AM GMT on October 15, 2005
Hey, Buckeye - Made it back.
Weatherboy - I agree that we may see something developing down around the Caribbean by Sun/Mon. Just what, I won't hazard a guess. Early days yet. And anything can happen.
Member Since: October 7, 2005 Posts: 229 Comments: 24573
139. buckeyefan1
11:58 PM GMT on October 14, 2005
Looks like the shear has dropped. I need to see the llc! I can't get Jamica radar to work
138. buckeyefan1
11:56 PM GMT on October 14, 2005
Bring on Wilma.. Stay away from us, but Bring it on!!
137. weatherboyfsu
11:52 PM GMT on October 14, 2005
One last thing...Wilma will be with us soon...maybe by tomorrow night........and could it be possible.....wilma entering the gulf by wednesday.....possible heading towards florida..........we will see......
Member Since: July 17, 2005 Posts: 0 Comments: 1025
136. buckeyefan1
11:40 PM GMT on October 14, 2005
Hi everyone!! I want to comment on the F4 tornado vs the Hurricane.. I was in the biggest tornado ever recorded, the Xenia tornado they wanted (and still do) say this was an F6 tornado. I know no such thing, but the power of this was awsome!! I have never seen anything that bad since. I was one of the lucky ones. Everything was destroyed, except for our house and the house next to us. When I moved to South Carolina, I experienced Hugo. I don't know what was worse! I wouldn't want a direct hit from either, but at least the tornado is over in a minute or two, where a hurricane can last hours.
135. ncsounder
11:37 PM GMT on October 14, 2005
Does this mean we will see an Alpha next week?
134. tornadoty
11:35 PM GMT on October 14, 2005
I'll be back later, guys. I need a break from blogging.
133. weatherboyfsu
11:26 PM GMT on October 14, 2005
Have a good night hurricanechaser
Member Since: July 17, 2005 Posts: 0 Comments: 1025
132. hurricanechaser
11:22 PM GMT on October 14, 2005
ok..goodnight guys..thanks for the time..talk with you again soon.

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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.