ATL: MATTHEW - Ex-Tropical Storm - Discussion

[CourierPR]

As I look at the loop posted by Hurakan I can see the circulation around 12N and 67W.

[tshizzle]

i see absolutely nothing there that says development

this thing isnt close to developing - probably down to 30 or 40%, if not lower, at 2PM

[ConvergenceZone]

I'm suprised they have this at 60% chance of development within 48 hours.... I thought it would be quite a bit lower, based upon how it looks now.

[Steve H.]

We probably won't see any development until the weekend. It looks like the western Caribbean will be waiting for another pulse of energy from the eastern Caribbean/South America.

[CourierPR]

I'm suprised they have this at 60% chance of development within 48 hours.... I thought it would be quite a bit lower, based upon how it looks now.

I disagree. It looks to be slowly coming together with better organization.

[HURAKAN]

For a developing system, it looks great. It will get its act together when it leaves South America behind.

[caneseddy]

Not many people were expecting this storm to develop right away; even Wxman57 stated that once it got away from South American and got closer to Central America is when we should see this develop

i agree WCarib/NW Carib is where this thing will intensify..patience

[Vortmax1]

It's a developing system...that's just how it appears to me.
50-60% chance in 48 hours sounds right on it.

[SoupBone]

http://www.bama.ua.edu/~jcsenkbeil/gy4570/formation.pdf

opening sentence says it all, yet still crickets here.

Anyone care to tackle this?



Regardless of heat content, this is at May levels, way below climo and from what I gather, is an impeding factor for this.

http://onlinelibrary.wiley.com/doi/10.1 ... 4/abstract

Excerpt- "it would appear difficult for cyclones or anticyclones of any reasonable size to develop significantly in low latitudes, with the exception of cyclones in a vertically unstable atmosphere."

I'm gonna bump this too to see if anyone with a more advanced knowledge can explain this. First time I've seen something explained this way....thanks Comanche.

[Sanibel]

Hang out. Lots of moisture down there. The Atlantic recurve pattern has thrown weird westward steering currents into the Caribbean. TWC said the strong ridge that is guiding this west could break down once 95L reaches the west Caribbean allowing a northward movement.

[ColinDelia]

http://www.bama.ua.edu/~jcsenkbeil/gy4570/formation.pdf

opening sentence says it all, yet still crickets here.

I'm interested in the answer too. Maybe start a separate thread and hope someone has the time to tackle what looks to me to require a nuanced answer. My guess is that for someone to do the topic full justice - since there are multiple ways to measure instability and such concepts as CAPE, Lifted Index and CISK in addition to "vertical Instability" could all be discussed in such an answer - someone might need to take considerable time in formulating a response.

I would point out that only a short while ago Karl became a tropical storm in the Caribbean.

[tolakram]

When Karl finally developed it was at higher latitudes and out of the graveyard. IMO 95L needs to move not only west but a little north if it's going to develop.

[srainhoutx]

A feature that I think some folks have forgotten is Georgette. It could well be some of the energy that the cut off low absorbs and interacts with the Upper Low IMO...

[chaser1]

First....Frank, I too remember the "good 'ol days" across from the U of M when Frank ( and later Sheets ) were directors there..... after working in satellite, Lixion was one of my favorite hurricane forecasters. Always did enjoy some of his ( and others' ) quirks and anecdotes - but I digress........now, as far as 95L is concerned......

I am "in the camp", that there is a world of difference ( to the U.S. ) whether or not 95L develops prior to C.A. landfall. Despite a lot of statistical and global model agreement, I am not convinced 95L will develop prior to landfall. Furthermore, while I would agree that "if and when" this system were to emerge into the Gulf, development would likely occur, I am at best 50/50 that this will eventually turn into a U.S. threat - because of the possibility that time may not allow for significant development prior to such interaction with Central America.

Last night's Euro seems to have a logical solution to 95L. Perhaps rather than a system already well developed in the W. Caribbean, then turning NNE ahead of a significant "fall like" short wave, I believe 95L may well remain an open wave or possibly develop into a Tropical Depression, all the while continuing further westward over Central America. Though a discernible LLC may continue to exist for days over land, such land interaction will hinder any significant development. Thereafter, this entire "blob" could feel some northward tug by mid/upper steering associated with a fairly sharp short wave or cutoff low, I do not believe that an already well developed storm will be pulled northward from the W. Caribbean, but perhaps rather a large broad low pressure area having camped out over land - more or less as the 0Z Euro might indicate. Granted, such an evolution, while after several days of sitting over land could lead to eventual development in the Southeast Gulf; in fact I think probably would. With the westerlies pretty far the north, I would think that any significant short wave that might play a short term role in helping to lift 95L into the southern Gulf, will be eventually replaced with at least weak ridging, and thus possibly steering a significant threat northwest ( or at least NNW ) towards points between the Lousiana/Texas border and perhaps Pensacola.

I would think next plausible scenario, is a system which remains low latitude and eventually migrates into the BOC, again later developing and posing threat to N. Mexico.

Perhaps because of the fact that this is a low latitude broad system , has not yet consolidated at the surface, and given that we are perhaps at least a few weeks away from the lower level steering beginning to slacken, there would seem to be a smaller window of opportunity for near term significant development to occur ( as well as any associated NW pull given a deeper system ).

What I just do NOT see happening, is what earlier runs of the GFS were indicating with perhaps a worse case scenario which would be a large storm to develop prior to landfall, and if only "clipping" Central America remaining under diffluent upper air all the while. Now, should a storm move towards the N.W. or North, and then as the same progressive trough which aided in lifting the storm into the S.E. Gulf just as quickly depart and more or less leave a sprawling and deepening hurricane in a COL......, well then we'd really have some areas of W. Cuba or perhaps the Florida Keys receiving lashing winds for a protracted period of time AND copious rain for days over a large area. Then, everyone from Brownsville to Key West would be waiting to see if an eventual building ridge drives the storm westward or some eventual short wave finally enhancing the flow to steer the storm north or N.E.'ward.


( ...just to be safe though, perhaps i'll just pick up some "crow" at the store, just in case I come home from work this evening, just to find a turning CDO the size of Texas in the Central Carib.!! LOL )

[CajunMama]

Anyone care to tackle this?

http://www.ssd.noaa.gov/PS/TROP/TCFP/da ... carins.png

Regardless of heat content, this is at May levels, way below climo and from what I gather, is an impeding factor for this.

http://onlinelibrary.wiley.com/doi/10.1 ... 4/abstract

Excerpt- "it would appear difficult for cyclones or anticyclones of any reasonable size to develop significantly in low latitudes, with the exception of cyclones in a vertically unstable atmosphere."

If you would explain this, this would be extremely helpful to the novices on the board. We've requested that all these graphs/pics have an explanation so that we may share our knowledge with those who don't know what they are. Pass on your knowledge please!

[dolebot_Broward_NW]

http://www.breathebonaire.com/index.php ... onairecam1


A view into 95L

[HURAKAN]

Latest

[Vortmax1]

As this day progresses Invest 95L is looking less organized with each new frame.
I take back what I said earlier about this being a developing system.
To be truly honest...this just looks like a Tropical Wave passing through the Caribbean right now.
Any development will not be happening in this current location.

[HURAKAN]

WTNT21 KNGU 221600
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 12.5N 69.4W TO 13.5N 77.0W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 25 KNOTS. METSAT IM-
AGERY AT 221500Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.5N 69.4W. THE SYSTEM IS MOVING WESTWARD AT 12 KNOTS.
2. REMARKS: CURRENT MODEL GUIDANCE IS DEPICTING GRADUAL
INTENSIFICATION OF A 1009MB LOW SITUATED NORTH OF VENEZUELA. THIS
SYSTEM IS MOVING WESTERLY AT APPROXIMATELY 12 KNOTS. THIS SYSTEM IS
MOVING TOWARD WARM SEA SURFACE TEMPERATURES OF 86 TO 88 DEGREES
FAHRENHEIT, DECREASING VERTICAL WIND SHEAR, AND AN UPPER LEVEL
ANTICYCLONE WHICH SHOULD HELP THE ENHANCE THE DEVELOPMENT OF THIS
TROPICAL FEATURE.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR
CANCELLED BY 231600Z.//

[HURAKAN]

Very unstable