Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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Update Friday 7/27... things are starting to perk up in the Eastern Atlantic with a well-defined tropical wave exiting the coast of Africa this evening. Model guidance suggests that the tropical Atlantic will become increasingly active as the upcoming week wears on.
Clark has posted a new blog on these developments and the tropical forecasting process; see it below on the main page or in the Blogs.
Update Sunday 7/23... Invest 97L has been issued but I think it's future is a non-event for most. Maybe a start for a so far slow season...
Original Post... Most of the Atlantic basin still remains quiet, however, a large but disorganized tropical wave has slowly increased in convective activity over the past couple of days in the eastern Caribbean Sea. Earlier today (19/20Z) a weak - and probably transient - mid-level circulation center was evident near 12N 66W. Movement to the west northwest at 10-12 knots - and that general movement is expected to continue for the next few days.
The wave, currently under light shear, will encounter some moderate westerly shear for the next day or two, so I wouldn't expect any significant near-term development. Over the weekend, as the system moves away from the shear zone, the wave has a better chance for some organization. SSTs in the central Caribbean Sea are about 28C. Something to watch over the next few days.
In the Central Pacific, Tropical Depression Cosme may well regain Tropical Storm intensity and pass just south of the main Hawaiian Islands on Saturday. You can follow CoconutCandy's excellent commentary on this system in the Other Storm Basins Forum.
Finally, a reminder that discussions based on long-range model projections belong in the Forecast Lounge rather than the Main Page thread.
ED
Edited by MikeC (Sat Jul 28 2007 02:51 PM)
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LoisCane
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So you are watching the system in the Atlantic not in the Carib. Is that how I understand it?
What do you think Ed about the models predicting development and a landfalling tropical system in the New England area down the road?
Was curious to your thoughts and others.
Thank you Ed, Bobbi
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http://hurricaneharbor.blogspot.com/
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Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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Loc: Melbourne, FL
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No, I'm watching the system in the Caribbean Sea. Since they are seldom correct, I don't bother with model outputs - and, as stated above, that topic belongs in the Forecast Lounge. Finally, and this is good advice for everyone, whenever you make a personal inquiry of someone, please use the PM capability.
Thanks,
ED
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danielw
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The winds at the San Juan NWS radar have begun to back over the last hour. From SSE to NNE at 0044Z.
This may or may not be indicative of the outer edges of the wave reaching the radar site. Wind speeds are up to 10knots at the 3000ft level. ( The radar site is located in mountainous terrain.)
Just something to watch...
San Juan NWS VAD Winds
Satellite imagery indicates the center of the wave is located SSE of St Croix, USVI. Using cirrus directional changes and lightning data in the NE through SSE areas of the wave. Appears to be moving NW at 10-15 knots. The system is very large. Covering the area from 60-70W.
GOES Puerto Rico RGB for Lightning Observation
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typhoon_tip
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Ed and gang,
My feeling is that an Invest should be scheduled sooner rather than later for the TW that is flaring moderate to heavy convection in the NE Caribbean.
Currently, the looping IR with deep layer wind composite layering shows a strong divergent vector field in the 200mb level, expanding, and situated nearly colocated with densest masses of convection. It is likely this is instrumental in giving additional lift and continued propagation of intense shower activity.
I am having trouble finding wind and pressure obs from that part of the Atlantic Basin that are up to the hour, but TPC reports that upwards of 3mb falls have occurred in the last 24 hours, as well as winds veering south over the Leeward Islands; and all this, prior to this evening's preceived intensification of convection. With difluence so strong and on-going deep tropospheric convection intensified [perhaps in nocturnal cyclic forcing], I would not be surprised if surface convegence were getting better defined.
I believe it is worth it, in part, because the Canadian had a rather intense system for several runs [its TC bias aside] and now we have a feature entering that same domain in an atmosphere increasingly more conducive to development. Granted, the 12Z had back off a bitl; however, the 12Z UKMET hints that it was sniffing something out, as did the , both showing pressure perturbations riding up the eastern flanks of the EC shear axis in the mid level westerlies in roughly concerted timing with the . The 18Z continued along this track with a subtle but yet clear pressure perturbation getting pulled north off the East Coast. And, it should be noted that the Global-based models will typically perform poorly until a tropical feature is better developed and in the sounding array at times of model initialization
Point being, given that there was a presence in the models at all, combined with observations this evening, I think it should peg for the and let her rip.
[Edit: I found this site and it is great! http://www.srh.noaa.gov/sju/caribm.html ]
John
Edited by typhoon_tip (Fri Jul 20 2007 01:35 AM)
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typhoon_tip
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Dan,
This is a nice site that I just found:
http://www.srh.noaa.gov/sju/caribm.html
...It was a few links down on the googling, which is why I missed it when I was looking earlier; not that you asked of course. Anyway, it may provide some key wind/pressure points as eval on this system is on-going...
[Edit: Interestingly...I am not finding the 2-3mb of pressure falls as TPC discussed; the winds in the northern Leewards are veered all the way around to the SW however]
John
Edited by typhoon_tip (Fri Jul 20 2007 01:30 AM)
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LoisCane
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Size of it is pretty interesting especially as it has held together it's shape for most of the day.
If there is a center time will tell but with models predicting development (on several runs) it's definitely worth watching carefully for any signs of investigation.
If they didn't think so they wouldn't have put it in the
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http://hurricaneharbor.blogspot.com/
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typhoon_tip
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Some annotations of interest... See attachment
These s and their associated trough axis will continue to provide an exhaust enhancement aloft. Currently, they are moving W slowly, concertedly with this wave/package of convection. This, overall, should provide continued favorability for growth in this region, when considering the strong divergence, on-going, aloft.
John
Edited by typhoon_tip (Fri Jul 20 2007 03:25 AM)
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lawgator
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Quote:
Ed and gang,
My feeling is that an Invest should be scheduled sooner rather than later for the TW that is flaring moderate to heavy convection in the NE Caribbean.
Your suggestion taken to heart....
Invest considered.
http://www.nhc.noaa.gov/text/MIAREPRPD.shtml?
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LoisCane
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sometimes when a wave splits the system is finally able to get it's act together.. wave seems to have split like the canadian showed and will have to watch it now to see if it will spin or fall apart..
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http://hurricaneharbor.blogspot.com/
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typhoon_tip
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Quote:
Quote:
Ed and gang,
My feeling is that an Invest should be scheduled sooner rather than later for the TW that is flaring moderate to heavy convection in the NE Caribbean.
Your suggestion taken to heart....
Invest considered.
http://www.nhc.noaa.gov/text/MIAREPRPD.shtml?
When my original posting was done there had just recently been a TPC statement released regarding southerly winds along the lower Leewards; suggesting at least a weakly closed surface circulation was evolving in the vicinity of the NE Caribbean. That, combined with the transiently impressive satellite presentation, and some favorable U/A conditions, is what prompted that optimism.
However, soon after making that post, I did my own analysis of the NE Caribbean and despite the TPC statement, I could not close off a circulation.
Lesson learned: Do own analysis first...so as not to be beguiled by other sources, because you take risk of drawing a false conclusion. [I think this was just a bad luck of sorts, though]
The problem is, you really have to close off a circulation of some kind before an Invest run can be made. The wind and pressure pattern may have hinted earlier in the evening, but by later on it was pretty non-descript and disorganized in that area.
Now, ...now that this wave splitting has taken place, we are in a new paradigm of sorts. What ever happens from here on out should be taken as analysis, anew. Whatever is left of the TW ...it is moving away from the upper level anticyclone and into a bit of WSW shear/jet channeling on the south side of the axis. This is not optimal for development -- although as noted by TPC, conditions could improve in a day or so. Not seeing an Invest out of this for the time being, though.
We'll see... otherwise, back to watching.
Edited by Ed Dunham (Fri Jul 20 2007 10:07 PM)
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weather_wise911
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As far as any short-term organization/development... I wouldn't get my hopes up. Now, looking into early next week, conditions should become more favorable for some organization. However, this system lacks any support from forecast models. Personally... I'll give it a 15% chance for development.
Take care...
WW-911
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weatherguy08
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It seems that as of the 10:30 AM CDT , the National Hurricane Center is giving the area of disturbed weather north of Hispaniola a little more hope: Quote:
UPPER-LEVEL WINDS ARE GRADUALLY BECOMING MORE
FAVORABLE...AND SOME DEVELOPMENT IS POSSIBLE IN THIS AREA OVER THE
NEXT DAY OR .
(Off-topic material was removed. As stated in the leadoff article for this thread, forecasts for system development based on model projections do not belong on the Main Page - they belong in the Forecast Lounge.)
Edited by Ed Dunham (Sun Jul 22 2007 02:31 PM)
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cieldumort
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Two flights have been tentatively been scheduled http://www.nhc.noaa.gov/text/MIAREPRPD_last.shtml?
1. SUSPECT AREA.
FLIGHT ONE
A. 22/1800Z
B. AFXXX 01DDA INVEST
C. 22/1300Z
D. 32.0N 64.0W
FLIGHT
A. 23/0600Z
B. AFXXX 0203A CYCLONE
C. 23/0100Z
D. 35.0N 64.5W
IMHO, as of this morning there is almost -nothing- there. Looking at 32N 64W the ULL in the region is still far too intense to allow anything at the surface to get going at those coordinates(LINK) . Also, surface pressures there are running a bit high. Additionally, the best low level convergence (LINK) , and indeed even the most impressive 850 mb vorticity -by far- has actually been centered well to the south of there for some time (LINK) .
For this "invest" to come together at that predetermined location by this time Sunday, I suspect that the ULL would need to really pull out of the way and/or weaken a good bit more. Neither appears to be happening at this time. For now, my attention remains focused -just barely- on or about 25N 64W.
Perhaps for a long-shot Invest, 13N 78W. Weak low to mid level cyclonic turning now evident in an already low shear and moist environment. Would probably still run into central America and/or cross in to the east Pac, regardless.
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Hurricane29
Weather Guru
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I see no worries with this system as the approaching cold front should keep it out to sea.
With the ULL still in place provide shear development looks unlikely in this area. Here you can see the convection with the cold-front the will sweep this mess out to sea.
Note:Recon will likely not fly out to investigate the area.
Edited by Hurricane29 (Sun Jul 22 2007 11:13 AM)
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Clark
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Just as a heads-up, following off of Ed's comment about SSTs in the basin, I've posted a new blog entry about the upcoming Cape Verde season. It's available just below the main article on the main page or directly by clicking here.
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Current Tropical Model Output Plots
(or view them on the main page for any active Atlantic storms!)
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cieldumort
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97L has been added.
Convection has been rather persistent, but any hint at a lower level cyclonic circulation might be a bit weak and fleeting just yet. Outflow has been reasonable, with the NE, E & SE sections all exhibiting decent outflow. The surface trof itself remains rather pronounced, and runs from roughly just NNE of Bermuda southwest for "several hundred miles," as mentioned in a few earlier s & TWDs. Shear is high just to its east, but rather low to moderate now right on top of much of it (LINK). SSTs are just about marginal, and drop below 26 c very soon along its track to the north, however (LINK).
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OUSHAWN
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Does anyone have an opinion on what is going on in the BOC this morning? I haven't been able to check anything out so was wondering what is causing that big blob down there. All I know is from the weather report I saw on our local news this morning they are expecting quite a bit of rain here through the weekend. Are there any models picking up on something trying to form out in the gulf?
Shawn
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Lee-Delray
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Saw this article on Yahoo this AM, thought it would be of interest.
http://www.yahoo.com/s/636164
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Hurricane29
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12z and showing signs of the cape verde season taking off?
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