Jacksonville low keeps on spinning

By: Dr. Jeff Masters , 01:46 PM GMT am 19. August 2006

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The persistent low pressure system about 50 miles east of Jacksonville Florida continues to kick up heavy thunderstorms and high winds over the waters off the Florida coast. Wind shear from a protuberance of the jet stream is still a very hefty 40-50 knots, and is expected to remain over 40 knots through Sunday, so development of this system into a tropical depression is not expected. However, radar animations out of Jacksonville, FL show a healthy circulation and some strong thunderstorms on the east and south sides. Wind speeds at a buoy 45 miles east-northeast of St. Augustine have been about 25 mph gusting to 30 mph this morning. A QuikSCAT satellite pass at 7:06am EDT this morning showed some wind gusts as high as 45 mph in some of the thunderstorms. The low could affect Georgia and northern Florida today and Sunday much as a tropical depression would, bringing heavy thunderstorms and gusty winds.


Figure 1. Current radar out of Jacksonville, FL.


Figure 2. Preliminary models tracks for the East Coast disturbance.

Elsewhere in the tropics
The strong tropical wave south of the Cape Verde Islands that the GFS model had been developing into a hurricane is now pretty ordinary looking. The GFS no longer develops this wave. A good general rule for model predictions of tropical storm formation:

1) If two or more of the reliable models (GFS, NOGAPS, GFDL, UKMET) are forecasting develoment, watch out.

2) If none of the reliable models are forecasting development, watch out. The models miss most tropical storm development.

3) If just one of the reliable models is forecasting development, you can probably discount it.

That being said, we have a case where two reliable models--the GFS and NOGAPS--are forecasting that the large tropical wave that will move off Africa Sunday will develop into a tropical storm by the middle of next week. However, the wave will have to contend with a large cloud of Saharan dust which has just emerged from the coast of Africa.

Wind shear remains high over the Caribbean today, but the GFS is forecasting that this will drop significantly by Wednesday, and remain very low for the ten days following. I expect at least one tropical storm will form in the Atlantic during the next seven days. One candidate might be a weak tropical wave currently in the mid-Atlantic near 11N 40W.

Jeff Masters

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1259. StormJunkie
9:36 AM EDT on August 20, 2006
ahhh the wonder of cyberspace where no one has to be quite and we all get to talk whenever we want :)

It's all good Rand happens all the time. The best is when you post something and someone post the exact opposite at the same time...lol You know you are in for a good debate then...
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1257. WPBHurricane05
9:35 AM EDT on August 20, 2006
i know just sounds good
Member Since: Juli 31, 2006 Posts: 56 Comments: 8112
1256. GoofOff
9:25 AM EDT on August 20, 2006
I enjoyed lurking on the blog last night. Lots of insults and other statements with little or no basis in fact. Thought of the times my cousins, sisters and I would be out in the yard arguing and my grandmother would come out and say "Children, play nice." And the doom and gloom group were like our first TV. We were about 100 miles from the transmitting tower and would see snow most of the time but get excited when it looked like something on the screen was moving and could have been a human being. We do that now with blobs. Technology is a wonderful thing. All things considered, the weather will do whatever it feels like.
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1255. StormJunkie
9:33 AM EDT on August 20, 2006
Sorry bout what Rand?
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1254. Thundercloud01221991
8:31 AM CDT on August 20, 2006
their have been seasons ith less storms
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1252. kmanislander
1:27 PM GMT on August 20, 2006
No question that the convection is increasing. What we have to watch for is persistence over the next 12 to 24 hrs and for what happens to the ULL

bb soon. Coffee time
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1251. WPBHurricane05
9:29 AM EDT on August 20, 2006
ok we have witnessed to record breaking seasons in a row:
2005-Most Named Storms
2006-Least Named Storms (shear)
Member Since: Juli 31, 2006 Posts: 56 Comments: 8112
1249. StormJunkie
9:26 AM EDT on August 20, 2006
Yes, Ike it is a few hours hold, there will be another one out soon. THe best way to identify shear is with the imagery if you want real time. I still see shear on the N side of the big blob.
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1248. IKE
8:26 AM CDT on August 20, 2006
There was a ULL NNW of there yesterday...easily visible on WV...but it's fading away as we type....or looks it to me.
Member Since: Juni 9, 2005 Posts: 23 Comments: 37860
1247. IKE
8:24 AM CDT on August 20, 2006
Posted By: kmanislander at 8:20 AM CDT on August 20, 2006.
Ike

there is a bit of a spin near 14N82W but that might be more in the upper levels. I would expect any low that develops to form in or near the deep convection further E. I have seen low centers jump around to wherever convection is strongest in the early stages of development. Lets hope your position is right though !


You may be right...I admit, I'm no expert. That convection looks more impressive each updated frame...ugh...you may have some rain headed your way.
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1246. kmanislander
1:22 PM GMT on August 20, 2006
there certainly doesn't seem to be anywhere near 20 or 30 knots of shear below the Nicaragua/Honduras border. The convection would not be hanging together like it is if there was
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1245. IKE
8:20 AM CDT on August 20, 2006
Posted By: Randrewl at 8:20 AM CDT on August 20, 2006.
Ike....a reliable shear map? What's that?


I understand.

SJ....that shear map link is at 0900UTC..isn't that 4-5 hours ago???
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1244. StormJunkie
9:21 AM EDT on August 20, 2006
lol Rand :)
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1243. StoryOfTheHurricane
8:19 AM EST on August 20, 2006
this is the strangest hurricane season i have ever witnessed
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1241. kmanislander
1:15 PM GMT on August 20, 2006
Ike

there is a bit of a spin near 14N82W but that might be more in the upper levels. I would expect any low that develops to form in or near the deep convection further E. I have seen low centers jump around to wherever convection is strongest in the early stages of development. Lets hope your position is right though !
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1240. StormJunkie
9:17 AM EDT on August 20, 2006
SWLA It looks like that area int he SW Carib is under 20 to 30kts of shear which is not conducive for development. Check here
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1239. IKE
8:16 AM CDT on August 20, 2006
Posted By: SWLAStormFanatic at 8:16 AM CDT on August 20, 2006.
Convection continues to fire in the SW Caribbean. Looking at the WV loop, I don't see anything impeding development. A few minutes ago, Steve Lyons said that upper level winds weren't favorable for development. What is he referring to?


Not sure..according to Tropical Weather discussion at 8:05 AM there is a high in the southern Caribbean.

Anyone have a reliable shear map they can link??
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1238. SWLAStormFanatic
1:13 PM GMT on August 20, 2006
Convection continues to fire in the SW Caribbean. Looking at the WV loop, I don't see anything impeding development. A few minutes ago, Steve Lyons said that upper level winds weren't favorable for development. What is he referring to?
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1236. StormJunkie
9:12 AM EDT on August 20, 2006
lol CWO ;)

I think the area that is in the W Carib that Rand is watching is what the MM5 puts in the Gulf. The GFS did want to do this, but has since backed off.

Take a look at the Genisis chart. Does not give the W Carib much, but that also does not mean much.
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1234. IKE
8:12 AM CDT on August 20, 2006
Posted By: CatWatchOne at 8:09 AM CDT on August 20, 2006.
luker and like it that way. I know alot of you dont put much stock in forecast models, but, according to Dr Masters, if 2 or more predict you may want to be aware. GFS, MM5FSU, NOGAPS all show the wave off Africa producing something and MM5FSU has something big in the GOM in the next few days. Havent heard it mentioned so thought I would.


I mentioned last night about the MM5FSu and NOGAPS having a gulf of Mexico storm in 5-6 days and was advised by someone to not rely on models that far out.

Hey...I was just relaying what these models were saying!
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1233. StoryOfTheHurricane
8:13 AM EST on August 20, 2006
and thats all i have to say about that.
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1231. StoryOfTheHurricane
8:01 AM EST on August 20, 2006
i rely on nhc more than anything else, from satellites to outlooks, but since weather is so unpredictable any prediction should be taken with a grain of salt bc anything could happen, and as for on here, when you have several different opinions, while only 1 being right, that one right one isnt always what nhc and everyone else thought would happen, and any warning should be taken seriously bc they are meant with good intentions
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1230. StormJunkie
9:09 AM EDT on August 20, 2006
Morning ya'll

I agree Rand, the E/Cent Atl is about ready to bust. Both the Nogaps and the GFS from two systems in this area over the next week. Not certain one of these two will make it, but I think this hints at how active the CV season will be.
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1229. kmanislander
1:07 PM GMT on August 20, 2006
we will know by tonight whether something is brewing down S or not. It will be interesting to see Dr.M's take on things today
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1228. CatWatchOne
1:09 PM GMT on August 20, 2006
luker and like it that way. I know alot of you dont put much stock in forecast models, but, according to Dr Masters, if 2 or more predict you may want to be aware. GFS, MM5FSU, NOGAPS all show the wave off Africa producing something and MM5FSU has something big in the GOM in the next few days. Havent heard it mentioned so thought I would.
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1227. WPBHurricane05
9:08 AM EDT on August 20, 2006
ok is the western carib. one because of the ITCZ??

and thank you
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1226. IKE
8:07 AM CDT on August 20, 2006
Seems to be a spin/turn...at about 14N, 82W.
Member Since: Juni 9, 2005 Posts: 23 Comments: 37860
1225. IKE
8:03 AM CDT on August 20, 2006
Hmmm...hopefully it will move inland.

Pressures down there are fairly low...I checked Nicaragua and Honduras...pressures are 29.80 to 29.86.
Member Since: Juni 9, 2005 Posts: 23 Comments: 37860
1223. WPBHurricane05
8:55 AM EDT on August 20, 2006
which storm do u guys think is forming i am doing 2 things at once
Member Since: Juli 31, 2006 Posts: 56 Comments: 8112
1222. kmanislander
12:59 PM GMT on August 20, 2006
Ike

I do live in The Caymans and I am watching I can assure you. Anything that forms there would most likely come up to the NW into or close to the South coast of Grand Cayman and my home is only 500 feet in from the beach on the S coast !!
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1221. IKE
7:56 AM CDT on August 20, 2006
Posted By: kmanislander at 7:55 AM CDT on August 20, 2006.
I ran a WV loop of the Caribbean and there is much more moisture pushing up from the S into the NW Caribbean today than yesterday afternoon. In fact it would seem that the ULL has weakened some and is starting a retreat which could open the door for development. If the convection down S persists into tomorrow and the ULL pulls away or weakens further development is a strong possibility. The GFS has shear way down in that region from late tomorrow


Do you live in the Cayman Islands???

If so, I'd be watching that system.
Member Since: Juni 9, 2005 Posts: 23 Comments: 37860
1220. kmanislander
12:48 PM GMT on August 20, 2006
I ran a WV loop of the Caribbean and there is much more moisture pushing up from the S into the NW Caribbean today than yesterday afternoon. In fact it would seem that the ULL has weakened some and is starting a retreat which could open the door for development. If the convection down S persists into tomorrow and the ULL pulls away or weakens further development is a strong possibility. The GFS has shear way down in that region from late tomorrow
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1218. SWLAStormFanatic
12:41 PM GMT on August 20, 2006
I think the NHC does a good job. They've got a job I wouldn't want. We can guess, speculate, prognosticate and copitulate and if we're wrong...who cares, it's just a blog. They've got a tremendous responsibility as hundreds, if not thousands of municipalities and governmental agencies, as well as the general public are looking to them as the final say.

As far as "classifying" a blob or discussing a potential wave, I think they have to be concerned with the "crying wolf" syndrome. It would be a different story if either one of the blobs in consideration were sitting in the Bay of Campeche. As far as needing to be prepared...that should have been completed June 1st.

I know there are various levels of knowledge and weather savy here on WU, but the vast majority want to pull the trigger on something developing, whereas the NHC seems to err more on the side of caution. (I speak in broad generalities here). Good grief, if the decisions were left up to the consensus of WU "forecasters", half of the U.S. coastal population would have been evacuated for Alberto, Beryl, Chris as well as half the blobs that have come within 500 miles of the coast.

Those are just some of my thoughts on the conversations circulating this AM on WU.
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1216. StoryOfTheHurricane
7:46 AM EST on August 20, 2006
itcz or not, i still say this thing is formin
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1214. StoryOfTheHurricane
7:41 AM EST on August 20, 2006
so a storm embedded in the itcz tends not to intensify and is only as good as the itcz convection is what you guys are saying?
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1213. kmanislander
12:38 PM GMT on August 20, 2006
randrewl

It would certainly seem so. Unfortunately the latest repositioning, if correct, makes the wave much more of a long term threat to the Islands given the current low latitude of the low center. This bears serious watching especially if it gets its act together late around 45 or 50W. The stronger a system is far out in the ATL the more likely it is to pull up to the N

kman
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1212. StoryOfTheHurricane
7:39 AM EST on August 20, 2006
lol jk
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1211. StoryOfTheHurricane
7:37 AM EST on August 20, 2006
i feel violated, damn the itcz
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1210. Tazmanian
5:36 AM PDT on August 20, 2006
hello not staying for long any thing new?
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1209. Stormy2day
8:35 AM EDT on August 20, 2006
Thanks for that Story - and, have a great day!
-stormy
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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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