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Busy Times in the Tropics This Week!...continued

By: Dr. Jeff Masters, 2:10 AM GMT on August 01, 2007

Guest blogger Margie Kieper

Tuesday evening update: Well, 36 hours have passed since Monday morning, and Usagi does indeed look impressive. JTWC has upgraded the intensity to 120 kt and the eye continues to clear out:

Usagi vis

With ocean heat content diminishing from here on, it's hard to see how Usagi can intensify more, but JTWC has forecast a super typhoon (130 kt).

TD-Eight was upgraded to TS Erick, with this charmer from Lixion Avila, "DVORAK T-NUMBERS AT 0000 UTC FROM BOTH TAFB AND SAB INSIST THAT THE SYSTEM IS A TROPICAL STORM."

* * * * * * *

Tuesday lunchtime update: Because of a busy workload and a sick kitty (Squeak; aka Furball, Metcat), updates today will be minimal, but I'll update with satellite imagery tonight. If you have questions, email them to viewfromthesurface at gmail...and I'll answer them, if I'm able.

The Pacific Ocean is on a roll today.

Invest 99E is continuing to look good this morning, and is likely a TD by now. Update: was designated TD-Eight this afternoon.

Usagi's appearance on satellite continues to improve on IR and water vapor imagery, and the underlying structure continues to improve as well, as this latest of 37gHz microwave images shows, and can be compared with the two others posted earlier in this blog entry:

Usagi 37gHz

Usagi's intensity has been increased to 115 kt by JTWC (1-minute max surface windspeed) and 80 kt (10-min wind) by JMA, and it is close to it's maximum intensity, as ocean heat content will steadily lower, between now and landfall in Japan, which should have an impact regardless of the excellent outflow. At the moment, Usagi is a very powerful typhoon.

Regards all the angst on the blog comments yesterday on 99L: Most important is that you will never hear hype from me when blogging about tropical disturbances. Seeing the ocean of dry air ahead of 99L, it was not difficult to have an idea about what was going to happen. Here's something to note: that area just off the South American coast is a kind of a sweet spot. There is always good divergence flowing north that, while it may resemble outflow, is not necessarily indicative of an increase in vorticity. The low level winds are just so, to support a developing low, moisture is drawn from the ITCZ...but many lows associated with a tropical wave that look good there, will fade afterwards when gaining latitude and leaving those conditions behind, especially if moving into a more hostile environment.

It appears the surface circulation of the low associated with Invest 99L opened up or elongated this morning, both on satellite imagery and looking at the earlier QuikSCAT. The dry air is preventing moisture from the ITCZ from making it to the disturbance as it gains latitude, and so it is losing definition. The tropical wave may find a better environment by the time it moves into the western Caribbean or into the East Pacific.

Tuesday morning update: Usagi in the West Pacific continues to steadily strengthen and improve in structure. This morning the eye cleared out, and most recently the structure of the core has become more symmetric. Usagi has been a large, rather sloppy-looking tropical cyclone overall, but don't be fooled by this appearance. As I mentioned yesterday morning, this typhoon should be looking fairly impressive by 00Z 1 August, in about nine hours from this post. Here is a microwave from earlier this morning showing consolidation in the center and continued banding of convection around the center:

Usagi 37gHz

There are two other areas being monitored in the West Pacific for possible development.

* * * * * * *

In the North Atlantic, as predicted by NHC yesterday, TD-Three has strengthened into Chantal, and strengthening has continued, tilted but clearly tropical, moving rapidly northeast and being pulled into the strong trough coming off the East Coast, spinning furiously like a biker pedaling downhill, on its way to extratropical transition. Life in the fast lane.

Invest 99L underwent a little reorganziation overnight and the mid-level circulation redeveloped in early morning, along with some banding structure. Convection continues to have a hard time sticking due to the dry air, but the low level organization is still intact, so there is some potential to develop into a tropical depression over the next day or so -- but as I said yesterday, chances are that nothing is going to come of this over the next day or so.

More recent morning imagery shows the low level circulation is becoming a little looser, as convection cannot be maintained. It appears this will fall apart as the day progresses.

Finally, there looks to be some potential for development - really, more potential than 99L, as there is quite a lot of energy in this area of disturbed weather - at the tail of the trough coming off the East Coast, east of Georgia and the Carolinas -- but again, a fish spinner.

In the East Pacific, Invest 99E has developed some convection to the southwest of the low level circulation, so that it is no longer an exposed "swirly." A microwave pass from this morning covered enough of the area to show the banding convection and a solid low level structure, so expect this to have potential to develop into a tropical depression as it heads out into the Pacific. Recent visual imagery shows good outflow has started to develop.

* * * * * * *

Monday evening update: Convection was able to reform over the center of the exposed low level center of invest 98L tonight, and it has become TD-Three, very near tropical storm strength. It is now centered well north of Bermuda and tracking northeast towards the tip of Newfoundland. The satellite floater is positioned so that the low off the SE coastline can also be observed for development, while TD-Three is rapidly moving north out of the image frame.

Earlier this evening, easterly shear pushed the mid-level circulation and convection right off of the low level center of invest 99L, where it spun off to the west and evaporated, as the low level center continued to move to the northwest, a process that was captured very clearly on the satellite imagery, as seen here on an IR from the NRL web site -- the gray scale helps to determine the height of the clouds:

99L sheared

As I mentioned earlier today, 99L is headed for a large area of dry air. This can be seen on the IR satellite imagery (here, RGB), which I've marked to show the successive surges of the Saharan Air Layer (SAL).

99L and SAL

Here a water vapor image clearly shows the extent of the dry air across the Atlantic and eastern Caribbean.

99L and dry air

In the West Pacific, Usagi has been steadily strengthening and the eye is starting to become visible on IR and VIS imagery. A microwave from this afternoon shows the solid inner ring of the low level circulation surrounding the eye, partially banded by strong convection (pink).

Usagi 37gHz

* * * * * * *

Monday Afternoon update: The very nice tropical wave that moved off Africa last Thursday, that is now located at about 50W, has developed rotation and convection and has been designated invest 99L by NHC. While the most recent surge of SAL only extends out to about 40W, most of the tropical North Atlantic and eastern Caribbean remain very dry, so once this wave moves out of the ITCZ and into the eastern Caribbean, chances are that nothing is going to come of it for the next two or three days. The vis loop already shows convection on the northeast and northwest side of the disturbance dissolving as it moves into the dry air.

Convection momentarily burst near the center of 98L, well north of Bermuda and on its way to the middle of the North Atlantic, before getting sheared by the upper level flow.

More on Usagi tonight.

Don't try to adjust that dial: Yes, it does appear that over the past week the NRL TC website has been quietly going berserk. Dalila is done, but keeps coming and going, as do various invests intermittently labeled "Lima" or "Bilis." One could say the site is suffering from Bilis-Lima-ia.

* * * * * * *

For Jeffs early August hurricane outlook, which came out Sunday, link here.

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Posted By: weathersp at 6:09 AM PDT on August 01, 2007.

Hey look at this guys and gals!! The NHC must be REALLy intersted if they planned 2 flights for 99L.

NOUS42 KNHC 311530
1130 AM EDT TUE 31 JULY 2007
VALID 01/1100Z TO 02/1100Z AUGUST 2007
TCPOD NUMBER.....07-069

FLIGHT ONE FLIGHT TWO A. 01/1800Z A. 02/1200Z
C. 01/1530Z C. 02/1000Z
D. 13.0N 57.0W D. 13.5N 61.5W
E. 01/1700Z TO 01/2200Z E. 02/1100Z TO 02/1600Z
F. SFC TO 10,000 FT F. SFC TO 10,000 FT


that for july 31st thats old and nots today fight plan
Quikscat link for Hi Res image

Look at the ascending pass for this morning. This evening will be the descending pass

You think they are flying in?
GFDL Has it Developing into a Cat 1 Just as it hits Belize -
Is this a Likely track?
When was Belize last hit.
Really Taz I think you might look a little bit more closely..

A. 01/1800Z
C. 01/1530Z
D. 13.0N 57.0W
E. 01/1700Z TO 01/2200Z
F. SFC TO 10,000 FT
Posted By: sporteguy03 at 1:12 PM GMT on August 01, 2007.

Thats why I say Recon goes in no Quickscat data and JP its close to the Islands and they want to see if its developing further.

Why do you say no data when the pass clearly covers 12N 57W and the center, if there is one, is near 12N 56W ?. The pass was 3 plus hrs ago when the center would have been further E even than that !
Hey Texas, Steve Lyons talked about the Gulf 3 days ago and said that we really need to watch it. Baromaters are holding steady right now. We do need to keep and I on it - much closer to home.
Firefox fan here too, although thinking of looking into SeaMonkey (Firefox fork).

On 99L, given that the time zone is UTC-4 hrs (AST), and sunrise there is 5:43 am AST, from watching the 30 frame GHCC IR loops it looks as though our intrepid 99L has continued to organize and slowly strengthen well past the diurnal max.

May be an interesting link to watch over the next 24 hours: Current Weather Conditions:
Grantley Adams, Barbados
(sorry if somebody already posted this)

Thanks to TerraNova for the Windward Islands radar link, plus a big thanks to ryang for giving us up close and personal reports!

bbl, gotta get some work done! :)
well I have to head off to work now but will check in later
No recent data I meant I saw the data you had but since it literally is trying to develop as we speak I feel they will investigate it further.
kman, the system should have been in the general area of 12N 56W about the time of that pass. Maybe even a little further W. It missed half the storm for sure and likely missed the center also.

Good morning, all!

If recon is still going out, then it looks like we may have a storm. Once more 99L has to maintain through daytime heating.

Current Steering
we see it sj. Hey sj have you seen the convection and surface low in the gom? It formed along an old frontal boundary last night. what do you think of that area shear is low there? go here:http://www.ssd.noaa.gov/goes/east/tatl/loop-rb.html and put up nws fronts to see it.

There was no closed low almost 4 hrs ago. A lot can, and probably will, change by the time of the scheduled recon. The sat images certainly suggest a West wind now but we need to watch for a wind shift first from NE to NW and then West at Trinidad and Tobago to confirm the existence of a West wind.
You can always go here and here for conditions in the caribbean.
Can Anyone See My comments - Or have I been Filtered out...
: (
Please let me know

ps kman, I am not saying there was or is a a closed low, was only pointing out that we only got half the structure of the wave at best.
I think we'll know if they fly or not by the 1130am TWO, I say they will go, just my take.

Go here for QS
The image you posted looks to have been taken from a buoy link which will not give you the same coverage. I still maintain there was no closed low when the sat passed over. We shall see how this plays out

noname-I see you
Yes SWFLBoy,
Thats what I been trying to say lol
I'm quoting but " but it continues to show signs of a low-level circulation" Accuweather
New Blog
12n,56w is still in the Itcz according to the latest sfc map; but in the sat loops, it looks like that may be changing. The upward kink in the Itcz looks to have dropped and will be further south, meaning that 99L is "finally" escaping.

Now, can it still make it w/out moisture from the Itcz? Not sure, but with daytime heating, it's gonna be tough. JMHO.
Posted By: NoNamePub at 1:27 PM GMT on August 01, 2007.
"Can Anyone See My comments - Or have I been Filtered out..."

NoNamePub - You show up on the next setting above "Show All". I always set to show all, I've seen some good posts from good people that get filtered otherwise. Blob Politics.
I tend to agree kman, I don't think it likely that there was a closed low, just not sure QS got the "center"

As far as that image goes, they are from the same page. You posted the 12.5km map and I was using the 25km page.
WTH? I think now the WU, CMC, and NRL site are all smokin' the same stuff. There is a new blog, I just posted in it, but now it is gone....Makes ya say hmm ~)
we see yah noname.
Webcams from Port St. Charles, Barbados:


Don't think we'll need them though since we have two excellent people on location :)
Thanks TN ☺

There is a new Dr M/Margie blog up. For some reason you have to click Dr. Masters name above and then click the permalink for the new blog. It is not in the main blogs title list yet. Very, Very strange...
Usagi, is that the third typhoon? It is obviously a Japanese name, and thier alphabet goes Ah, Ee, U, Eh, Oh. Do Indian Ocean Typhoons get Inidan names and Pacific Typhoons get Japanese names? Where do I look for info on that?

If the Gulf is so dry, why did my house in north florida get 5 inches of rain yesterday? There was quite a wet band across the state and that water is comming from somewhere. Don't get me wrong, we NEED it and I'm glad more is forecast. I'm just puzzled by the Gulf is Dry comment.
99L is now feeding from the NW also. This is new. We should see TD4 status this afternoon.
Here is the discussion out of Mobile this AM

Area forecast discussion
National Weather Service Mobile Alabama
1145 am CDT Wednesday Aug 1 2007

....Long term (thursday through next wednesday)...for the past several
model runs...the NAM...GFS and Gem have all wanted to form up a low
over the quasi-stationary boundary along or just south of the Gulf
Coast on Thursday...transitioning it gradually inland through
Friday. Today the GFS solution is more widely accepted with a weak
low forming up near the mouth of the Mississippi...moving slowly
north across the Mobile Bay area through Friday. The 00z NAM and
Gem forecasts taking the weak low farther to the west across
southeast Louisiana. We keep our highest/likely probability of precipitation going over the
western Florida Panhandle for Thursday and Friday...in the area of
greater moisture convergence. Odds are...either the GFS or the Gem
will verify in this pattern...and both have a likely pop scenario
painted for the central Gulf Coast on Friday. This is all inline
with the previous forecast package as well. We also went a bit
higher with the quantitative precipitation forecast values over the Panhandle Friday afternoon with
several areas forecast to have between 1 and 3 inches of rainfall
from Thursday night through early Saturday...very close to the
00-06z HPC forecast. For the remainder of the extended period...we
basically Delaware-amplify the upper trough over the southeastern states
and build a ridge just west of the area by early next week. We saw
no reason to discount the GFS/mex forecast probability of precipitation through the later
periods of the extended. /05
...Marine...a weak area of low pressure is expected to develop along a
stalled front across southeast Louisiana on Thursday. The motion of
the low after that is where the disagreement lies. The GFS takes the
low to the north across southwest Alabama. The NAM develops the low
across south central Louisiana and drifts is west northwest. Both
the UKMET and European model (ecmwf) support the GFS. Thus have used the GFS solution
for the marine wind forecast and in coordination west/ surrounding
offices have capped the wind speeds at 15 kts and sea heights at 4
feet until a better handle on development and strength can be
gained. /13