MikeC
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Loc: Orlando, FL 28.49N 81.47W
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Saturday (09/30) 11AM Update
Isaac now a minimal hurricane with 65 knot sustained winds - moving to the northwest at 5 knots and located over 650 miles east southeast of Bermuda. Isaac expected to turn more northerly and eventually north northeasterly in advance of a strong frontal system now off the east coast. Isaac, as a strong system, expected to head off into the north central Atlantic and may brush extreme eastern Canada with some squally weather next week.
As September comes to a close, nothing of any real concern going on in the rest of the Atlantic basin. Invest 97L has faded and another wave in the southern Caribbean Sea has weakened. One remaining large wave over Africa at 30/12Z near 12N 6E, however, it may not even make it to the African west coast - the Cape Verde environment has changed and CV activity is over for this season.
Perhaps one more baroclinically induced hybrid before this season ends - but not too much of a chance for even that type of a system to evolve as the SSTs begin to cool and the subtropical jet intensifies. The week ahead (perhaps two) looks quiet.
ED
Thursday Update - 11AM
At 11AM will upgrade TD 9 to Tropical Storm Isaac with sustained winds of 35 knots. The system has moved under a weak upper level low - and manages to survive. The position under the low has actually reduced vertical shear. Movement continues to the northwest.
Invest 97L now active as well as another area well east of the Windward Islands - see the Storm Forum for additional details.
ED
Original Post
Tropical Depression nine has formed in the Central Atlantic, yet another fish spinner.
TD#9 is forecast to move northward, gradually strengthening. Not approaching any US land areas, and staying out to sea. It has some chance to strengthen into a tropical storm, but likely not enough to reach hurricane strength.
This continues the 180 season from last year, if it keeps up we thankfully may very well get through the season without a landfalling US hurricane.
Mike
Hurricane Isaac
Animated Model Plot
Animated Model Plot
SFWMD Model Plot
More model runs on from Jonathan Vigh's page
Visible Satellite Floater
IR
Animated Floater with overlays
Edited by Ed Dunham (Sat Sep 30 2006 12:16 PM)
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Ed in Va
Weather Master
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The storm has two very distinct areas of convection. What bearing would having one or the other becoming the primary one do to the track...anything?
http://www.ssd.noaa.gov/goes/flt/t1/avn.jpg
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Survived Carol and Edna '54 in Maine. Guess this kind of dates me!
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Steve H1
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Loc: Palm Bay FL USA
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97L up now for real. I've been watching this since it separated from 09L. This should become a TD/TS in the next 24 - 36 hours, passing through the Leewards today and tonight. Who knows, if it avoids the shear to the NW, it may threaten the SE in the long range. Looking soewhat impressive on satellite. Ignore the old Tuesday plot that's on .....it way off. Currently the Invest is at 18N/60.2W. Definitely something to watch, particularly for Puerto Rico. Cheers!!
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LoisCane
Senior Storm Chaser
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Loc: South Florida
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Hey Steve.
Hard to get excited about TD9 but the Invest by the islands shows potential.
Also, there is a lot of shear out of ahead of it and a diving sort of trough to it's west but...
think that it has pretty much reached it's low point and the set up in a day or two might be interesting.
Either way, it begs watching. It has consistency going for it too.
As for TD 9.. that forecast path is consistent too...
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http://hurricaneharbor.blogspot.com/
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Lee-Delray
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We now have TS Isaac spinning in the Atlantic, but I guess that was predicted. Though I guess 97L, if it turns into Joyce will be the big topic.
Edited by Lee-Delray (Thu Sep 28 2006 11:09 AM)
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LoisCane
Senior Storm Chaser
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Loc: South Florida
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Joyce would be cool... will check out Isaac.. Could clip New Foundland ya know?
Still looks like a big Upper Level Low to me.
Thanks, really would like thoughts on the wave
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http://hurricaneharbor.blogspot.com/
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Steve H1
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Yeah Lois, Isaac looks like he's destined for the open waters. 97L looks a bit odd right now, but has held together, small as it is. With everything having such difficulty getting organized this year, we can't forget it CAN happen. Ed was also looking the the wave ESE of the Windwards. Its pretty far to the south, but has the structure a something that could develop. If this was 2005 I'd say its definitely a go. But this year i cast doubt on everything. Conditions just haven't been that favorable. But think we'll be getting into a surge of development during the next few weeks. Then bring on the cold fronts!!
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Clark
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Loc: Great Lakes 45.95N 84.55W
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To me, Isaac looks definitively subtropical at best, at worst, with the convection displaced to the north of the storm in sort of a "delta" shape and a well-defined feeder band/frontal structure extending to the southwest (coincidentally, 97L is flaring up at the tail end of that boundary). The QuikSCAT passover mentioned in the 11a discussion only clipped the east side of the storm, so it's tough to discern anything significant from that, but based on the current satellite appearance -- I'd have to go with subtropical. However, I've never seen them reclassify a tropical system as subtropical in the middle of the game, so it's likely tropical until they call it . The track guidance looks good and it's one for the fish.
97L is probably one for the fish as well if it gets going thanks to a rather large upper trough along the eastern seaboard. If it doesn't get going, it might sneak into the Florida peninsula and bring some moisture and a chance of rain. Wouldn't worry about it much right now.
The east Atlantic is effectively shut off with a sharp upper trough across the entire basin. Once that thing takes hold this time of year, it's hard to budge. Would bet pretty fair money that we've seen the last of the CV storms for this season.
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Ed in Va
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Clark,
What about the disturbance at 10/50, if it survives past South America?
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Survived Carol and Edna '54 in Maine. Guess this kind of dates me!
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Clark
Meteorologist
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Loc: Great Lakes 45.95N 84.55W
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I would tend to say it looks like a run-of-the-mill flareup in a region of weak diffluence aloft and convergence at the surface and low levels. There's not much signature of a true wave/inverted V feature in either the 850hPa streamline analysis or QuikSCAT winds (what winds are available, at least). I don't see it gaining much latitude under ENE winds at low levels and think it'll likely head into at least the north portion of S. America. Nothing to worry about, in my estimation.
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cieldumort
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I would really take exception with calling Isaac extra-tropical in nature - certainly subtropical, yes - but, as you point out, is unlikely to go back mid-stream and reclassify it as such -- however, they repeatedly do make references to it's subtropical nature. It reminds me quite a bit of a June subtropical cyclone that went unnamed ( 06/24/2345 UTC 34.4N 51.1W ST1.5/1.5 92L ) -- and certainly if Isaac can be classified as a 40kt "tropical" storm, June's 92L really is deserving of a post-season up to 40 kt subtropical, to say the least, IMHO. They are/were nearly twins. One thing for certain, Isaac is no ULL - not by a long shot.
97L is practically DOA tonight, but I wouldn't write it off just yet, as it has been one tenacious low all along -- especially in light of it's fight with 96L Norte all of this past week. While still looking abysmal, it's weak condition may allow it to slide a little further west just yet - and you know - sometimes all these things need is one good night of relaxed shear and/or notably higher SSTs to pop.
Speaking of ULLs -- really is lots of diffluence-enhanced convection associated with that 25N 32W on it's eastern side - and, there is some reflection at the surface -- I guess personally I will be watching it over the next few days for some slightly possible chance of slow development, just in case -
Real story as of late seems to be the Pacific, once again. All's not quiet on the western front.
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Lee-Delray
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Is 97L a goner? From the 5:30 looks like the is saying so.
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Ed in Va
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Looks like it's on life support. Even if holds together, it should be swept away by the front off FL. Have noticed a little flare-up off Nicaragua(?), but it looks like it's died down some.
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Survived Carol and Edna '54 in Maine. Guess this kind of dates me!
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HanKFranK
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isaac looks like the lesser version of what we've been seeing all september, post-ernesto. the ragged, subtropical appearance it has been exhibiting much of its life has already been duly noted; will be interesting to see if it improves once it gets out of the 'wake' of the previous hurricanes.
97L probably isn't worth biting at. the synoptic environment is giving it a less favorable shot than isaac (and isaac isn't really there by much), and it hasn't been as convectively active as before. it'll probably become indistinct as it drifts westward-wnw.
probably the best shot at a next system is the deep layer low developing south of the azores. i know, why not another east atlantic fishspinner, right? the globals have it cut-off from the westerlies over marginal waters, sort of stuck under a tilted rex-block most of next week. it'll develop a surface reflection... at least isn't showing much warm-core transition, but that sort of thing isn't uncommon.
for october... in spite of some sharp amplifications in the east, the kind of deep longwave trough that needs to drop in for a few days to get the caribbean cranked up doesn't appear in the offing for the near term. there is something like that happening around next weekend, and in spite of lowered pressures the models (at least the ones i've seen) don't show much out of it. it's likely just a tad too far east, as heights will remain high centered over texas... that sort of pattern usually causes anything that were to develop to just zip westward rather than come up.
big typhoon in the south china sea that ripped through the central phillipines is driving westward towards north/central vietnam right now. the westpac is active.. until something sputters up in the eastpac, we're probably going to be under the influence of quiet unless an october cut-off or pattern-induced type storm gets going. african waves are quieting down. with the already mature autumn pattern we're in, i'm not expecting much more activity, unless things really jam up somewhere, or the subtropical ridge makes a brief summer-like resurgence.
HF 1525z29september
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Lee-Delray
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HF
Might be a stupid question, but does an "Indian Summer" warm up in October effect storms off the east coast of the US?
I also note that Dr. Masters in his blog seems to be leaning the same way for October, with not much activity.
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Clark
Meteorologist
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Loc: Great Lakes 45.95N 84.55W
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Isaac is looking better now, though I would still argue it was more subtropical than tropical yesterday. It's sort of lived an odd life, with tropical origins, finally getting going with an upper-level boost, then working out of that back to more of a tropical state. Goes to show that not every storm is quite alike.
I won't disagree that yesterday's Isaac looked a lot like that early season feature along the eastern seaboard and I wouldn't be shocked to see a very short subtropical lifespan added in the post-season report, but I also wouldn't be shocked to see it not added either (more likely IMO).
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Lee-Delray
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From the :
Shower activity associated with a weak area of low pressure just north of the U.S. Virgin Islands has diminished.
Good news to start the weekend.
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cieldumort
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Loc: Texas 30.40N 97.80W
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It does appear as of this afternoon that Isaac has just about worked out the last remnants of being essentially subtropical, and does now forecast Isaac to become a hurricane. Nova Scotia may want to pay attention just a skosh, as the track has been shifted a bit left, as well. Looks like Isaac may not be out to just spin fish, and with his mechanics being partly ULL/cooler upper-level temperature -induced, he may still surprise a little on the upside like an Epsilon-type of animal. Being that the large-scale features in the states are now very much more like mid to late Fall, this really would not surprise me.
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SebLouis12
Unregistered
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Unless something forms very close to U.S., I.E. Florida,or Gulf Coast States Our U.S. Hurricane Season Is Over, Never Really Began. Something like that would probably stay weak, and not even be too major of a problem. Anything else in the east or central Atalantic should hook up and out. Fronts comming down should be our real concern at this time, we'll see what the next several weeks hold. The way I see it, any other opinions?
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Ed in Va
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I think you've got it. Looks like the remnants of old 97 are showing a little life south of the DR this am. If it holds together, it could remain far enough south to avoid the EC troughs and develop.
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Survived Carol and Edna '54 in Maine. Guess this kind of dates me!
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