Developments off the U.S East Coast

By: Dr. Jeff Masters , 1:12 PM GMT on July 17, 2006

Share this Blog
0
+

A cold front that pushed off the U.S. East Coast this weekend stalled out, and has spawned two areas of low pressure. The first is an extratropical or subtropical low that developed along the north portion of the front. This low is about 300 miles east-southeast of Cape Cod, Massachusetts, and is moving northeast away from the U.S. The storm is over the Gulf Stream where water temperatures are in the upper 70s, which is borderline for a tropical storm. The low has a large area of heavy thunderstorms on the northeast side of the center of circulation, and is undergoing significant wind shear that is exposing the center. To my eye, the system is probably a subtropical storm, and technically should be classified as Subtropical Depression Two. However, is it difficult to tell for sure, and the NHC is conservatively not naming it, since it is headed towards colder water and has little chance of becoming a full tropical storm.

>
Figure 1. Visible satellite image for 8am EDT July 17 2006, showing the various areas of interest along the East Coast.

The departing low has left behind the tail end of the old cold front over the waters off the South Carolina/North Carolina coast. This old front could serve as the focus for some tropical development over the next few days. There is a narrow area of reduced wind shear of 10-15 knots over this region, and the GFS computer model is indicating that the area of reduced shear will remain. Steering currents are weak, so it is difficult to tell where this system might go. The models seem to lean towards it heading northeast up the coast, possibly brushing Cape Hatteras and Nova Scotia later in the week. However, the system is currently very broad and disorganized, and any development will be slow to occur.

A very large area of concentrated thunderstorms is a few hundred miles north of Puerto Rico. This is associated with a tropical wave interacting with an upper-level low pressure system. Wind shear is 25-35 knots over this area, and no tropical development is expected. We will have to watch this area later in the week as it approaches the East Coast, as wind shear may fall and allow some slow development.

A solid-looking tropical wave has just emerged off the coast of Africa, and is headed towards the Cape Verde Islands at 15-20 mph. Water temperatures and wind shear are marginal for tropical development in this region, and I'm not expecting this wave to be a threat. It's very common this time of year to see impressive looking waves come off the coast of Africa, only to fizzle after spending a day over the water. By early August, I'll start taking these waves more seriously, when the waters are a bit warmer.

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: 276 - 226

Page: 1 | 2 | 3 | 4 | 5 | 6Blog Index

275. hurricane23
7:09 PM GMT on July 17, 2006
97 Recon Schedule...

Free Image Hosting at www.ImageShack.us
Member Since: May 14, 2006 Posts: 8 Comments: 13841
274. quakeman55
7:09 PM GMT on July 17, 2006
Dr. Masters has a new blog.
Member Since: March 31, 2002 Posts: 1 Comments: 1276
273. StormJunkie
7:07 PM GMT on July 17, 2006
Ya'll want tracking software?

Check this.
Member Since: August 17, 2005 Posts: 26 Comments: 16874
272. wxhatt
7:07 PM GMT on July 17, 2006
I have a free account here at wunderground, and to have access to the mailbox, but it doesn't seem to work? Is that for paying members only? Also wondering if I can receive mail though, and what the address would be. wxhatt@wunderground.com?
Member Since: October 5, 2005 Posts: 2 Comments: 930
271. Cavin Rawlins
6:58 PM GMT on July 17, 2006
global tracks is as cool as Tracking the eye.Net..thanks
Member Since: July 24, 2005 Posts: 407 Comments: 19076
270. Cavin Rawlins
6:52 PM GMT on July 17, 2006
Posted By: StormW at 2:35 PM AST on July 17, 2006.
wxhatt,
It's hurricane tracking software from extremeweather. GT7 (Global Tracks 7) If you can give me your email address I'll send some examples by attachment. Very good program. It imports all the data from NHC, JTWC, ETC. You can overlay satellite, model forecast tracks, wind swath, even has a wind table to tell you when and what wind speed to expect at a certain location.


can you send me some at weather underground
Member Since: July 24, 2005 Posts: 407 Comments: 19076
269. RedMosquito
6:46 PM GMT on July 17, 2006
StormW

Go to this website and learn some html tags.

Lurn gud stuff hear
268. hurricane23
6:44 PM GMT on July 17, 2006
18:00z Run of BAM models for 97L...

If DSHP is right this will be a 45kt storm.

DISTURBANCE INVEST (AL972006) ON 20060717 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS... ...36 HRS...
060717 1800 060718 0600 060718 1800 060719 0600

LAT LON LAT LON LAT LON LAT LON
BAMD 31.0N 75.5W 30.6N 75.9W 30.4N 76.4W 30.1N 76.8W
BAMM 31.0N 75.5W 30.7N 76.3W 30.6N 77.3W 30.2N 78.4W
A98E 31.0N 75.5W 30.3N 75.5W 30.3N 75.2W 30.2N 75.5W
LBAR 31.0N 75.5W 30.5N 76.2W 30.8N 77.0W 31.4N 77.8W
SHIP 25KTS 31KTS 36KTS 41KTS
DSHP 25KTS 31KTS 36KTS 41KTS

...48 HRS... ...72 HRS... ...96 HRS... ..120 HRS...
060719 1800 060720 1800 060721 1800 060722 1800

LAT LON LAT LON LAT LON LAT LON
BAMD 29.9N 77.3W 29.9N 78.2W 30.0N 79.2W 30.0N 79.9W
BAMM 30.1N 79.4W 30.1N 82.0W 30.4N 85.1W 30.9N 86.8W
A98E 30.2N 75.4W 29.6N 75.0W 29.2N 74.2W 29.0N 73.7W
LBAR 31.9N 78.5W 33.4N 79.8W 35.1N 78.9W 36.6N 73.3W
SHIP 45KTS 50KTS 50KTS 49KTS
DSHP 45KTS 38KTS 28KTS 27KTS

...INITIAL CONDITIONS...
LATCUR = 31.0N LONCUR = 75.5W DIRCUR = 190DEG SPDCUR = 5KT
LATM12 = 31.9N LONM12 = 75.3W DIRM12 = 192DEG SPDM12 = 4KT
LATM24 = 32.7N LONM24 = 75.2W
WNDCUR = 25KT RMAXWD = 40NM WNDM12 = 20KT
CENPRS = 1012MB OUTPRS = 1015MB OUTRAD = 150NM SDEPTH = D
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

Member Since: May 14, 2006 Posts: 8 Comments: 13841
267. hurricane23
6:40 PM GMT on July 17, 2006
As far as the system of Africa...

Still at the 18:00z full disk image it looks very good.

For those who can't see the image,you have to register for free.

Member Since: May 14, 2006 Posts: 8 Comments: 13841
264. wxhatt
6:38 PM GMT on July 17, 2006
sounds like a very useful program StormW. I just used the link that 23 posted. Thanks to All.
Member Since: October 5, 2005 Posts: 2 Comments: 930
263. StormJunkie
6:38 PM GMT on July 17, 2006
C2, it looks like the whole thing is still being pushed S and E.

This is 97L. Click the Most Recent button for the size image you want. There is clearly some circulation centered around 31.1 77.8. Not well organized by any means.

It looks to me as if the NW side is getting sheared while it is trying to build over from the SW side.

Member Since: August 17, 2005 Posts: 26 Comments: 16874
261. hurricane23
6:35 PM GMT on July 17, 2006
Global Track 7

Hurricane Tracking Software Worldwide...Good Software.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
260. C2News
6:35 PM GMT on July 17, 2006
yeah i know what you ae talking about though....what model is most dependable
Member Since: July 17, 2006 Posts: 73 Comments: 622
258. wxhatt
6:31 PM GMT on July 17, 2006
StormW what kind of software is the GT7?
Member Since: October 5, 2005 Posts: 2 Comments: 930
257. wxhatt
6:30 PM GMT on July 17, 2006
Can't say C2News. Without a fix on a LLC (low level center) it's very hard to tell.
Member Since: October 5, 2005 Posts: 2 Comments: 930
254. hurricane23
6:27 PM GMT on July 17, 2006
YEA MY BAD 2 TIMES....LOL!
Member Since: May 14, 2006 Posts: 8 Comments: 13841
253. C2News
6:27 PM GMT on July 17, 2006
anyone have an idea where the distrubance off the carolina coast is drifting?
Member Since: July 17, 2006 Posts: 73 Comments: 622
252. hurricane23
6:26 PM GMT on July 17, 2006
Close up Visible pic of 97L...


Member Since: May 14, 2006 Posts: 8 Comments: 13841
251. Tazmanian
6:26 PM GMT on July 17, 2006
we have a TS now?


some one say that this have 50mph dos the make it a sub -tropical TS now or what?

hmmmmmmm sub way lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115436
248. turtlehurricane
6:22 PM GMT on July 17, 2006
Here is a REAL CLOSE VIEW of 97L on Ramsdis.Also try the loop u can clearly see the LLC.

Thats in the East Pacific. Try the GHCC for close ups but, there is nothing spinning in 97L at this time.
Member Since: July 22, 2005 Posts: 227 Comments: 469
246. StormJunkie
6:21 PM GMT on July 17, 2006
Yes rain it is, I was about to point that out also. The link 23 just posted is a sat image centered on 10 N 100W
Member Since: August 17, 2005 Posts: 26 Comments: 16874
245. Tazmanian
6:20 PM GMT on July 17, 2006
we have a TS now?
Member Since: May 21, 2006 Posts: 5091 Comments: 115436
244. nash28
6:20 PM GMT on July 17, 2006
Yeah, it seemed a little high to me after I calculated it, but didn't realize it until I read your post.

Member Since: July 11, 2005 Posts: 190 Comments: 16972
243. highndry
6:19 PM GMT on July 17, 2006
hurricane23 - but I thought Stormtop made it clear that it was written in stone that there were to be NO TDs or TSs 'till August? ;-) I guess those invests are just going to have to wait for a couple of weeks.
242. StormJunkie
6:19 PM GMT on July 17, 2006
I concur with turtle and 03, the ships is not realiable with weak or unformed systems. But to answer your question it would be about 50mph. 1 knot is about 1.15mph.



Member Since: August 17, 2005 Posts: 26 Comments: 16874
240. raindancer
6:18 PM GMT on July 17, 2006
hurricane23 - Your image of 97L is actually in the Pacific (100 W) - isn't it?
Member Since: September 14, 2001 Posts: 0 Comments: 79
239. nash28
6:17 PM GMT on July 17, 2006
Oops!! StormW, I goofed and multiplied by 1.5 instead of 1.15.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
238. wxhatt
6:17 PM GMT on July 17, 2006
Been looking at the vis and do see the low level circ, but there is clearly a lack of thunderstorm activity associated with the disturbance. Must be due to the fact that the front is still somewhat active. I think your right weatherguy03, it will take a high to build over it to create the ventilation for thunderstorms to develope.
Member Since: October 5, 2005 Posts: 2 Comments: 930
237. WSI
6:16 PM GMT on July 17, 2006
"Yes, I dont look at the SHIPS at this point. "

You also can't really have a good idea of path on anything that hasn't formed yet either, mainly because there is no center to get a fix on.
235. hurricane23
6:15 PM GMT on July 17, 2006
Tazmanian go to my blog....There some pics there.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
234. hurricane23
6:14 PM GMT on July 17, 2006
hey SJ whats up?I was mentioning earlier that this buoy started the day with a WSW wind and it has now swung to the ENE so the low clearly drifted south past this buoy today.Theres no doubt about it that theres a weak LLC its just a matter of if it develops or not and i think a TD or atleast a sub-TD is really looking like a possibilty now.

Here is a REAL CLOSE VIEW of 97L on Ramsdis.Also try the loop u can clearly see the LLC.
Member Since: May 14, 2006 Posts: 8 Comments: 13841
233. nash28
6:14 PM GMT on July 17, 2006
I really believe the wave off Africa is going to be a player over the next few days. If it can avoid the horrendous shear to its north and head due west, then it has an excellent chance of becoming a TD or TS within the next 72 hrs.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
232. weatherguy03
6:14 PM GMT on July 17, 2006
Yes, I dont look at the SHIPS at this point. Turtle is correct.
Member Since: July 5, 2005 Posts: 592 Comments: 29708
231. turtlehurricane
6:13 PM GMT on July 17, 2006
What's 44Kts in MPH. Because the ships model has it there in 120 hours from now.

Don't use SHIPS on storms that havent formed or are weak ;)
Member Since: July 22, 2005 Posts: 227 Comments: 469
229. nash28
6:12 PM GMT on July 17, 2006
About 66mph.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
228. weatherguy03
6:12 PM GMT on July 17, 2006
But, a TD or TS would not suprise me. Well, back to work:(
Member Since: July 5, 2005 Posts: 592 Comments: 29708
227. NWAtlanticCyclone
6:11 PM GMT on July 17, 2006
What's 44Kts in MPH. Because the ships model has it there in 120 hours from now.
226. weatherguy03
6:11 PM GMT on July 17, 2006
Doesnt look all that organized today. Will have to see if High Pressure can build over it the next day or two. Shear is still low. I still have a feeling we are gonna see something out of this, with a slow movement to the west or nw. The models still arent too keen on it yet, and thats what makes me hesitate a bit.
Member Since: July 5, 2005 Posts: 592 Comments: 29708

Viewing: 276 - 226

Page: 1 | 2 | 3 | 4 | 5 | 6Blog 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.

Local Weather

Overcast
48 °F
Overcast