MikeC
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9AM Update 31 July 2007
A special disturbance update has upgraded Tropical Depression #3 into Tropical Storm Chantal. Still moving away from the US. Regular advisories for Chantal will begin at 11AM.
99L is not looking as good as it was yesterday, but if it persists through the day it still has a chance to develop within the next few days. For this one, watch to see if it kicks back up in the evening tonight. It managed to pull in dryer air, despite being having a lot of moisture yesterday. So currently, chances are dropping that 99L will develop into anything, but it is still important to watch for persistence during the day.
Original Update
There is a very late July development in the form of tropical Depression #3, which has formed in the eastern Atlantic. Also, a wave east of the Caribbean islands is something to watch. The tropics are waking up to an interesting start to the month of August.
Tropical depression three is moving away from US land areas and should not affect them. It is moving over warmer waters and has a chance to become the third Tropical Storm of the season, if it does it will be called Chantal. Shortly after it will likely become , so it would be short lived. Newfoundland in Canada will have to deal with a tropical or system zooming by, however.
Also a system is being watched east of the Leeward Caribbean Islands. This is being referred to as Investigation 99L.
Chances for Tropical Development of Wave East of the Caribbean (99L)
Code:
(forget it) 0 1 2 3 4 5 6 7 8 9 10 (sure thing)
[-----*--------------]
There is some chance for development over the next few days, folks in the Eastern Caribbean islands will want to watch this one. The usual pattern is, if it remains weak it will likely continue westward and have trouble gaining strength, at least initially. However, if it strengthens more as it approaches the Caribbean islands it may tend to move it a bit further north. At this point, models are a bit still too immature to gather any good information with. A day or two more of persistence will be what to really watch in this regard.
Intensity wise, 99L is looking very healthy, but still has a few negative factors associated with it, but this one has more positive factors than negative. If it persists (likely) and a low level circulation starts happening, it could be sooner rather than later. The atmosphere to the west of it is fairly wet, and shear isn't too bad, so conditions are there for it, now persistence is the key to it. And could develop within the next day or so, if it holds through the day on the 31st, then this will be the first potential system that deserves some serious attention this year.
When it arrives in the Eastern Caribbean it will have to deal with slightly higher shear, and more hostile conditions for development, so that may cause this system not to develop so much.
99L is a surprise from the thinking of late last week, our eyes were glancing more toward the gulf, while this wave kicked up.
More to come on both systems as needed...
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AmateurJohn
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Fun with maps --
I just clicked on the TD3 graphic under Current Storms in the menu on the left. The Weather Plot map just under Track Map has some interesting geography. It seems France has moved to where Newfoundland used to be, and the United Kingdom has floated all the way down to the Caribbean Sea. Is this new for the 2007 hurricane season? 
Seems like someone was having fun while waiting for the next storm to pop up. 
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Lake Placid - 27.3N 81.3W
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danielw
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As of Midnight Eastern time, 99L is beginning to look more like a tropical system. Newly formed, over the last 4 hours, -type central convective area. Quite a bit more lightning than 4 hours ago, when there wasn't any visible in the sat imagery.
Dvorak loop indicating cloud top temperatures colder than -70C. Using the coldest IR temperatures they appear just NW of 11N/ 48W. type structure is somewhat elongated to the NW. I'll call that light windshear. Not much, just enough to elongate the mid levels. NE quadrant is still lacking mid to high level clouds. Low level clouds are visible. Probably the dry air or SAL in the NE quadrant.
Long loop doesn't really reveal much more than the short loop.
Two other small areas to watch. The North Central GOM coastal area... front moving south with High Pressure over the N GOM. And the convective system just off the SC Coast.
Minor areas, and close to land... but it's nearly August and anything is possible in August. 
edit: While the type area certainly appears detached frrom the outer banding clouds. The speed at which the center is increasing areal coverage is amazing. One other note. I hope that Clark can offer a comment here. The clouds on the western semicircle appear to be wrapping around clockwise toward the Equator.
Early indicator of an Equatorial Outflow Channel?0414Z
99L Floater Page
99L long loop
99L Short Loop
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Random Chaos
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99L is definitely throwing off more convection (source SSD) tonight; question is: how much of this is result of diurnal effects and how much is strengthening. I wouldn't be surprised if we woke up to a TD, though.
Given it's pre-TS strength, models shouldn't be that good yet at predicting it's growth and motion, but what I'm seeing shows it growing nicely through the next few days across almost all models. Uniform westward motion is predicted. doesn't seem to be initializing it yet. As I said, it's early. Track and strength really isn't going to be good for another day or two, probably (until it hits TS strength, I haven't found models very reliable).
Nice catch with , AmateurJohn - someone should tell him.
Edited by Random Chaos (Tue Jul 31 2007 04:24 AM)
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weather_wise911
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It seems that 99L might have a good shot at short-term development... but long-term development is still very much in question--as far as I'm concerned........ for the very reason mentioned in the link below.
http://img402.imageshack.us/img402/5751/wvfu9.png
Take care...
WW-911
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danielw
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Update From
MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
125 AM EDT TUE JUL 31 2007 edited~danielw
CARIBBEAN AND TROPICAL N ATLC...
A 1011 MB LOW HAS DEVELOPED ALONG A TROPICAL WAVE E OF THE LESSER ANTILLES NEAR 10N49W MOVING W ABOUT 15 KT.
SINCE ABOUT 00 UTC THE LOW HAS DEVELOPED A SIGNIFICANT BURST OF DEEP CONVECTION... AND CONDITIONS APPEAR FAVORABLE FOR POSSIBLE
TROPICAL DEPRESSION FORMATION OVER THE NEXT 24-48 HRS.
THIS TYPE OF WORDING WILL BE MENTIONED IN THE FCST. MODEL GUIDANCE CONTINUES TO TRACK THE SYSTEM TO THE WNW OVER THE NEXT 5 DAYS...
CROSSING INTO THE TROPICAL N ATLC WATERS TONIGHT... ACROSS THE WINDWARD ISLANDS WED NIGHT... THEN THROUGH THE REST OF THE CARIBBEAN THU THROUGH SAT.
AT THIS POINT... ONLY THE 12Z AND 12Z CANADIAN TRACK A CLOSED LOW THROUGH THE CARIBBEAN... SO WILL CONTINUE TO KEEP WINDS AT A MODERATE LEVEL UNTIL WE SEE MORE CONSENSUS.
REGARDLESS... THE TROPICAL WAVE MOVING W WITH THE LOW SHOULD BE STRONG ENOUGH FOR GUSTY 20-25 KT WINDS TO SPREAD ACROSS THE LESSER ANTILLES AND CARIBBEAN WATERS THROUGH THE WEEK.
(This is a bit long and some of it is forecast discussion not present weather. But it's a very good wrap up of 99L~danielw)
0138 EDT
Edited by danielw (Tue Jul 31 2007 05:43 AM)
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Beach
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Looks like 99L is really getting it together.
http://www.ssd.noaa.gov/goes/flt/t2/loop-ir2.html
http://www.ssd.noaa.gov/goes/east/carb/loop-wv.html
It really wouldn't surprise me if it is TD 4 or named by 5:00pm.
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Random Chaos
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Re: weather_wise911
While there isn't much moisture ahead of it, it also doesn't look detrimental to it's development. Take a look at the Saharan Air Layer, which is usually the largest impact on negative development; it shows the influx of hot, dry, dusty Saharan air ending just north of the system. Thus what's ahead of 99L is dry, but not adversely dry.
Storm is still holding together. I agree, TD could be mentioned at anytime. Models are still having a hard time picking up the low - only the is showing it well.
Edited by Random Chaos (Tue Jul 31 2007 12:00 PM)
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WeatherNut
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Looks like we have Chantal in the north Atlantic...not much of a threat though
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Born into Cleo (64)...been stuck on em ever since
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allan
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Welcome Chantal, in my opinion, it should have been classified at 5 p.m. yesterday. For some reason, it's getting stronger every hour. About 99L, it's not dying, the wunderground bloggers are wrong. The system still has a circulation, yes it has lost convection, but it's normal for that to happen in daytime. Remember that carribean wave 2 weeks ago? It flared up in the afternoon when it was supposed to blow up at night, so lets see what happens with 99L.
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Allan Reed - 18,9,5
Edited by allan (Tue Jul 31 2007 02:46 PM)
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Rich B
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OK, my take
Chantal: Set to become extratropic by around 1200z, 1st August, probably just before the centre passes over the Avalon Peninsula, bringing heavy rains and gusty winds. CHC is forecasting totals over 100mm for parts of the Avalon and southeastern Newfoundland, so could be a problem. Uncertainty in forecast track means winds to tropical storm / gale force may occur over coastal sections, especially in gusts. This time tomorrow, Chantal will be racing into the far North Atlantic.
99L: Not as well organised as earlier, granted. But even so, there is still well defined banding especially to the south, with an area of deep convection south of the centre. The LLCC is difficult to locate given higher level cloud, but looking at imagery it would appear it may be less well defined than earlier. The environment is ok though, and tonights diurnal max could give it the kick start it needs.
Cheers
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Rich B
SkyWarn UK
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Storm Hunter
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99L... i would expect some flare up tonight of storms... down the road, i think this has the best chance of getting goin... once it crosses into the caribean... its going to be a better conditions down the road.. 4-6 days from now. A few models are trying to flare something up in the GOM... off the front that just came through... takes it towards the Big Bend of Florida... as just a open low? Things are becoming active... still expect them to lower the official forecast just a nudge coming up.
12 STORM_1 pcp
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cieldumort
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Chantal is becoming now. There was a good burst of deep convective banding about the center, including the southern half which had been rather dry earlier, but this is also giving up the ghost as a dry slot wraps around from the west and south, and strong upper level winds continue to impart a lot of shear while she is already passing over waters well below 70 degrees fahrenheit. It is off to become a potent Chantal, perhaps even attaining hurricane-force as an ET.
The low to the south of Chantal is still quite wrapped up in the fronts, but has acquired some slight tropical characteristics. This remains a bit of a long shot, but it is noteworthy that the area from about 26N/75W up to 38N/67W does exhibit some decent lower level vorticity. Ship report out from 32N/70W at 00Z out of the WSW at 35 knots, and pressures as low as 29.64. Might be a one-off, or even inaccurate, but worth making note of.
Shear in the area probably remains its largest inhibitor. There is, however, a sweet spot in there already, and as the system accelerates to the northeast, net effective shear could come down. Again, a long shot, and not a threat to the lower 48, regardless.
On the tail end of this frontal boundary, it appears that it is in the process of leaving a trof draped across the upper GOM. With upper winds aloft turning anticyclonic, and shear coming way down from levels most often seen over the past several months, as Dem5 and others have already pointed out, this could become a region that we really have to watch. After all, anything which forms there will be 100% land-locked.
Also possibly something of concern during the course of the first week in August is the already invest-tagged "99L", about to start bringing rainy weather to the Lesser Antilles. It is entirely conceivable, based not only on climatology, but also on the nocturnal enhancement taking place tonight, that as 99L approaches the islands and the winds sort of slow down and thunderstorms bunch up and start to coalesce some more there, that it crosses over into a numberable system, as early as within the next 24 hours. Beyond that, it enters the eastern Caribbean "graveyard" and will be left to do some battle with that environment before perhaps finding another slightly favorable region further west.
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weather_wise911
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Certainly seems like 99L is lacking little more than closing off the low on the west side to be a tropical depression. However, as I mentioned earlier... while short-term development does seem likely--in the long-run, shear & dry air should prevail.
Take care...
WW-911
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ftlaudbob
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99L is looking very well this morning,convection appears to be very close to the LLC.We could have TD4 when recon gets out there this afternoon. http://www.ssd.noaa.gov/goes/flt/t2/wv-l.jpg
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Survived: 10 hurricanes in Rhode Island,Florida and the Yucatan of Mexico .
Edited by ftlaudbob (Wed Aug 01 2007 01:43 PM)
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HCW
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99L seems to be off the Navy site now but they have issued a formation alert . I still don't expect it to do much untill it gets into the carib .I also wonder why the recon info hasn't be updated since yesterday .
http://www.nlmoc.navy.mil/center/Tropical/wtnt01.gif
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weather_wise911
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Quote:
99L seems to be off the Navy site now but they have issued a formation alert
Here is the text of the alert...
A LOW PRESSURE CENTER LOCATED EAST OF THE LESSER
ANTILLES HAS FORMED UNDERNEATH VERY INTENSE CONVECTIVE
ACTIVITY. SYNOPTIC OBSERVATIONS INDICATED LOW PRESSURE
CENTERED NEAR 12.0N 58.0W WITH A CENTRAL PRESSURE OF
1010.0 MB. WIND SHEAR OVER THE SYSTEM IS ANALYZED AT
5 TO 10 KNOTS. THE CONVECTION ASSOCIATED WITH THE
SYSTEM IS BECOMING WELL ORGANIZED AROUND THE CENTER.
FURTHERMORE, SEA SURFACE TEMPERATURES OF 84F/29C IN THE
AREA CAN ENHANCE TROPICAL CYCLONE DEVELOPMENT OVER THE
NEXT 24 TO 48 HOURS.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR
CANCELLED BY 021300Z AUG 2007.//
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Steve
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Of more immediate concern to the U.S. and A. is the likely formation of low pressure off the mouth of the Mississippi River. Models are in general disagreement as to the future, but all of the major globals and the (fka ETA) do close off low pressure somewhere from the Mouth of the Mississippi River to south of the FL/AL state line.
The NAM, which is generally discounted in tropical scenarios, did a nice job last week with the Texas/LA rainfall when none of the globals saw it. So whether or not it can be trusted to hit twice within 2 weeks is up for debate. Solutions range from a stationary low to something moving into AL/FL to SE LA . Afterward, some models want to nudge it north to northeast while others (including NAM) bring it WNW across Louisiana as high pressure builds in from the Atlantic.
This will be a relatively short time span if low pressure forms and if it takes on tropical characteristics. We're talking about something forming Thursday or Friday with roughly immediate impacts for the coast. Whether this is a hybrid, frontal low, tropical depression/storm or whatever remains to be seen. But we'll have action this week to talk about.
*edit* Looks like they've got RECON on standby for tomorrow afternoon:
I. ATLANTIC REQUIREMENTS
4. SUSPECT AREA (GULF OF MEXICO)
FLIGHT ONE
A. 02/1800Z
B. AFXXX 01EEA INVEST
C. 02/1730Z
D. 29.0N 88.0W
E. 02/1745Z TO 02/2200Z
F. SFC TO 10,000 FT
Steve
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nc_tropical_wx79
Weather Guru
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Does 99L have a closed low or is it still an open wave because I couldn't tell by the last/latest Quickscat if there was one or not.
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W.D. Duncan
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Robert
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000
ABNT20 KNHC 011510
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT WED AUG 1 2007
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
THE AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE LOCATED
JUST EAST OF THE WINDWARD ISLANDS HAS BECOME A LITTLE BETTER
ORGANIZED THIS MORNING. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS
SCHEDULED TO INVESTIGATE THIS AREA THIS AFTERNOON. WHILE
ENVIRONMENTAL CONDITIONS DO NOT APPEAR ESPECIALLY FAVORABLE FOR
DEVELOPMENT...THERE IS STILL SOME POTENTIAL FOR THIS SYSTEM TO
BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR AS IT MOVES
WESTWARD NEAR 15 TO 20 MPH. REGARDLESS OF WHETHER DEVELOPMENT
OCCURS...THIS SYSTEM WILL LIKELY BRING SQUALLS TO THE WINDWARD
ISLANDS DURING THE NEXT DAY OR SO.
Just taking some excerps from this (ENVIRONMENTAL CONDITIONS DO NOT APPEAR ESPECIALLY FAVORABLE FOR DEVELOPMENT) Meaning this system wont develop and it will struggle through the carribean and just keep us antsy. as the sytem gets closer to south america the normal trough over venezuala wil rob 99L of inflow and kill it. There is a slight chance it could meangle with the old frontal zone in the gulf later this week. All in All i wouldent excpect any reall true development till early next week at the earlyest i would almost go as far as to say nothing till at least the 15th.
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