MikeCAdministrator
(Admin)
Tue Sep 21 2010 09:35 AM
Matthew Forecast Lounge

Invest 95L, in the Eastern Caribbean is being tracked, and this has a larger than usual chance of impacting somewhere along the Gulf coast. Early model runs take it toward the west, but some of the more dynamic models such as the GFS, Euro, CMC, and NOGAPS take it more northward.

Until the system develops it's pretty much in lounge territory, the odds slightly favor the turn north, but there is still quite a bit of uncertainty. Time will tell, but the early indicators are leaning toward a potentially anxious situation next week.


MikeCAdministrator
(Admin)
Tue Sep 21 2010 07:26 PM
Re: Invest 95L Forecast Lounge

95L has a lot of model uncertainty in the future, and will probably be a difficult system to track. The trend from today is west then northeast into Florida,

What likely will make it difficult to track is the idea that it may sit in the Northwestern Caribbean waiting for something to nudge it either further westward into the Yucatan, or Northeast into Florida. Both are possible, with west more likely if the system moves faster.

If the storm stays over water there is plenty of moisture and the positive MJO to give it a real shot to become this year's sixth major hurricane.

Moving northeasterly depends on interaction with a possible cold front at that time.


danielwAdministrator
(Moderator)
Tue Sep 21 2010 10:08 PM
Re: Invest 95L Forecast Lounge

Just checking the latest model run. 00z output is still trending with Mike's post above.
Either the models take 95L into Nicaragua, or they follow a nice curve toward the Yucatan Channel/ Western Cuba at the 5 day/ 120 hour time frame mark.

This could place the system in the NW Caribbean by Saturday or Sunday. Those living or vacationing in Southern Florida, Western Cuba and the Yucatan area should keep a real close eye on what the system does over the next few days and which direction it is drifting.


Owlguin
(Weather Hobbyist)
Wed Sep 22 2010 08:16 AM
Re: Invest 95L Forecast Lounge

Upgraded to red and 60% now. Definately something to watch. It appears that the models are having a difficult time determining the strength of the trough that is expected to turn it north. Right now though, it still looks like to me that the west coast of Florida or the panhandle are possibilities. If it stays over water, we could have a much bigger problem.

MikeCAdministrator
(Admin)
Wed Sep 22 2010 08:32 AM
Re: Invest 95L Forecast Lounge

Last nights GFS (0z) had it going into South Florida and then rakin gthe coast all the way to New York City. Others this morning are more into Pensacola.

HRWF keeps it over water and near Western Cuba, with a lean toward Florida.

Euro slams it into Honduras/Nicaragua then back over water, clips western Cuba and into Southwest Florida. (Hits florida overnight Sep 30 into oct 1).



weathernet
(Storm Tracker)
Wed Sep 22 2010 09:47 AM
Re: Lisa and The Caribbean Wave

Interesting to see that NHC has up'd 95L to 60% ( with surface obs to support forecast ), yet morning satellite would seem to indicate that no significant consolidation has occurred overnight, with this fairly large and broad low to mid level circulation. Given that the wave itself is moving along, and proximity to South America is at least temporarily preventing ideal surface convergence, a less developed system would typically continue to briskly move along with the lower level flow ( BAMS ) and be less apt to gain latitude in the very near term. These factors may be indicative of this morning's 12Z model runs seemingly more convergent towards the west. Even if a broad circulation does in fact exist, limited surface obs indicating west winds might indicate that a fairly well identified circulation still remains just above the surface. Last nights Euro though still attempting to eventually lift a broad system northward into the Southeast Gulf, has backed off the prior run's more intense modeling. Should development be delayed, this could play out like many late season monsoon troughs that often develop over Central America ( borne from either Pacific or Atlantic origin ) and only slowly lift poleward - all the while only slowly developing given the obvious land interaction. Such systems are capable of tremendous flooding over Central America, but by the time they lift northward into the Gulf the same steering conditions finally lifting the system northward, is also impairing increasing S.W. shear. Whether or not a well developed 95L does eventually lift out of the W. Caribbean, increased land interaction would not only hasten localized flooding conditions over Central America, but perhaps also develop into a significant rain event for parts of Western Cuba and Florida.

(Please keep long range assessments in the Forecast Lounge.)


MichaelA
(Weather Analyst)
Wed Sep 22 2010 10:10 AM
Re: Invest 95L Forecast Lounge

Still way too early to say what scenario will come into play. I'm just keeping a wary eye on the situation until there is a definite center fix on a defined system and the model runs become more consistent.

hogrunr
(Weather Guru)
Wed Sep 22 2010 10:38 AM
Re: Invest 95L Forecast Lounge

I agree, the 00z ECMFW, for instance, has several areas of low pressure that have potential for development in the vicinity of 95L, one is further north and one is further west. So until one of these actually develops, the model is simply making a best guess as to where the potential system will begin it's development. The beginning point is crucial to model accuracy.

weathernet
(Storm Tracker)
Wed Sep 22 2010 10:39 AM
Re: Invest 95L Forecast Lounge

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. Though 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 - more or less as the 0Z Euro might indicate. Granted, such an evolution could lead to eventual development in the Southeast Gulf; in fact I think probably will. 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.

Next plausible scenario is a system which remains low latitude and eventually migrates into the BOC, again posing threat to N. Mexico or perhaps Brownsville.

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 limited period of time for 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.


OrlandoDan
(Weather Master)
Thu Sep 23 2010 06:23 AM
Re: Invest 95L Forecast Lounge

So....Just about anything that could happen, might happen.

weathernet
(Storm Tracker)
Thu Sep 23 2010 08:27 AM
Re: Invest 95L Forecast Lounge

Funny as it sounds...., I'd say that "anything could happen" is a pretty fair appraisal of 95L. Differing models seem to be fluctuating with regards to their own respective forecasts. As of this a.m., most recent GFDL model is suddenly more "bullish" that ever and brings a powerful hurricane near or over South Florida, while the HWRF which has consistently re-curved this system out of the Caribbean and seemingly towards Florida or the southeast Gulf, now keeps 95L far to the south and into the BOC. The global GFS and Euro have been "generally" consistent with their own overall solution, though their intensity forecasts have been up and down.

As of this writing, we do not have an organized deep systems, so models really cannot be relied upon for too much accuracy and to an extent are basically attempting to forecast a "what if" scenario.

With edit to my own post........case in point! In error I realized that it was last night's GFDL 0Z run that very aggressively develops 95L, and just a quickly the 6Z has backed off a lot and track appears more ambiguous.


Thunderbird12
(Meteorologist)
Thu Sep 23 2010 10:47 AM
Re: Invest 95L Forecast Lounge

There seems be better agreement now on taking 95L into Central America, though if it develops quickly it may try to gain more latitude. Both the GFS and Euro have been taking 95L into Central America, but then developing another system close on its heels that takes a more northerly track through the Caribbean and potentially into the Gulf. Given the major pattern change forecast over the eastern U.S. and potentially one or more tropical systems trying to develop in the Caribbean, the long range forecast is particularly uncertain right now.

MikeCAdministrator
(Admin)
Thu Sep 23 2010 03:43 PM
Re: TD#15 Forecast Lounge

The Euro for next Friday has it over south/central Florida:

Ed in Va
(Weather Master)
Thu Sep 23 2010 04:08 PM
Re: TD#15 Forecast Lounge

Pretty wierd track...will we get another track update at 5, or will this be the one until 11?

MikeCAdministrator
(Admin)
Thu Sep 23 2010 04:14 PM
Re: TD#15 Forecast Lounge

Quote:

Pretty wierd track...will we get another track update at 5, or will this be the one until 11?




They are doing a full update at 5, so yes another track. Odds are they won't change much though.


Thunderbird12
(Meteorologist)
Thu Sep 23 2010 10:17 PM
Re: TD#15 Forecast Lounge

The 12Z Euro seems to move Matthew into Central America and lose track of it, then develops another system over the Caribbean which moves northward. The 18Z GFS seems to keep some version of Matthew alive, first over the BOC and then back over the western Caribbean, and develops another system further east over the Caribbean, which eventually slingshots to the north around Matthew, which basically moves slowly and erratically (with a general trend to the NE) to the end of the forecast run. Both models have indicated a very large circulation developing in the 7-10 day timeframe, which is tropical (warm core) in nature but with the potential for some baroclinic interaction.

Both of these model solutions are pretty anomalous and in remains to be seen how things develop down the road.


Edski
(Verified CFHC User)
Fri Sep 24 2010 12:08 AM
Re: TD#15 Forecast Lounge

What I'm seeing is 3 of 14 models have it as over water at 120 hrs. If it is over water at that point it's a crap shoot, and I'll be stocked up and ready to bolt up I-75...

Well if it's over the Bay of Campeche I worry a bit less.

We really have to look for an excess northerly component to the overal storm motion as it has a relatively rapid recurve, or just a more rapid onset of a less severe recurve. Either way, more northerly motion for the next 30 hours increases the time this storm avoids land, and the chances it misses land totally before getting caught up by the next trough that digs in...where this thing could be in 120 hours, and the steering currents it'll possibly not have, makes me a little nervous living near Tampa.


MichaelA
(Weather Analyst)
Fri Sep 24 2010 10:38 AM
Re: TD#15 Forecast Lounge

The question remains whether that second center is Matthew or a new storm. The models really don't have a long term grip on this at all.

danielwAdministrator
(Moderator)
Fri Sep 24 2010 10:58 AM
Matthew Forecast Lounge

The second system could be one of the reasons that some of the models are showing a hairpin 180 degree turn. System 1 follows the track to the west, and system 2 arrives, develops, insert word of choice, at the eastern end of the hairpin turn... poof. Number two is alive. Just my thoughts at the moment.

MichaelA
(Weather Analyst)
Fri Sep 24 2010 11:37 AM
Re: Matthew Forecast Lounge

Is this the potential second system that some of the models are trying to show?



MikeCAdministrator
(Admin)
Fri Sep 24 2010 12:09 PM
Re: Matthew Forecast Lounge

It's very possible, and actually increasingly likely.

It resembles a western pacific monsoon pattern than anything, and whatever develops from it could form a large area of rain and winds. It may not be purely tropical.



weathernet
(Storm Tracker)
Fri Sep 24 2010 01:17 PM
Re: Matthew Forecast Lounge

Quote:

Is this the potential second system that some of the models are trying to show?






Yep, my thoughts exactly. Of course the convection in the S. Central Caribbean is firing up nicely, but over the last few frames, I've noticed what I thought was actually a small area of turning ( mid level ? ) right on or just inside the coastline of Northeastern Venezuela. Either way, the spacing would seem more or less probable for whatever wave that came after Matthew, might be near this longitude. It would be pretty odd to see "our side of the world", that quickly develop a 2nd tropical cyclone - that fast. This would seem to fit the GFS's recent days of runs insistence of a 2nd low forming in relative close proximity to Matthew ( obviously much closer had Matthew stalled off the C. America coastline ).

With the recent global model's insistence I'm nearly convinced at this point that we'll soon see Nicole emerge from the Caribbean. A new system could of course just as easily be farther south than where the Euro/GFS solutions were indicating that Matthew might strike South Florida ( from Yucatan area ). Should newly developed cyclogenesis truly occur, but perhaps south ( or well south ) of 20 latitude, than it would seem clear that the impact of such timing and steering might render the current Euro/GFS solution of a South Florida impact to be "bogus". It remains to be seen if such a threat might once again exist next week, or it that threat might be placed elsewhere altogether.


MichaelA
(Weather Analyst)
Fri Sep 24 2010 05:58 PM
Re: Matthew Forecast Lounge

There is also a small ULL over Hispaniola which is imparting some shear over the northern edge of that area, but it appears that there is some upper level divergence farther South. I don't see any organization or circulation in the region yet, but I believe it needs to be watched over the next few days.

Thunderbird12
(Meteorologist)
Fri Sep 24 2010 06:00 PM
Re: Matthew Forecast Lounge

As MikeC mentioned above, the low pressure system that may form over the Caribbean later in the week may not be fully tropical, at least in the sense of being a typical tropical storm/hurricane. While the models can't fully resolve a hurricane, the GFS and ECMWF are capable of producing compact tropical cyclones of hurricane strength. Neither of those models do that with the potential Caribbean system... rather the low pressure they develop is a order of magnitude larger than a typical tropical storm and the pressure gradient is pretty flat (rather than ramping up quickly near the center). You can also tell from the forecast precip pattern that it is not a typical tropical cyclone, with no well-defined QPF bullseyes near the center. Anything that gets as far north as FL or the GOM may also become involved with a cold front and undergo some baroclinic interaction.

This is not to say that a true tropical cyclone (of the type that NHC is concerned with) could not form, but it looks like it would be a case of a smaller-scale vortex developing from or within a broad low pressure area, rather than the usual case of a small-scale disturbance growing upscale into a tropical cyclone.

Also, while it seems likely that Matthew will dissipate over land, that can't be taken for granted at this point. The forecast becomes even more complex if that hangs around in some form.


berrywr
(Weather Analyst)
Fri Sep 24 2010 06:17 PM
Re: Matthew Forecast Lounge

This is the problem with Matthew. Honduras is not flat except along the coast; it's mountainous. Where the shades of grey begin are when Matthew's mid level center decouples from it's surface and low level center. The mid level center should continue west and possibly emerge on the Pacific side. It is the low level center and where it goes that decide if it's Matthew that re-emerges into the Caribbean, a combination of both systems; Matthew's low level circulation and the disturbance farther to the east depicted on satellite and models up to 500 millibars. I poured over the 12Z package today and I think it will be Nicole, not Matthew. Whatever develops is likely to strike the US given the pattern shift and Typhoon Malakas becoming a powerful post-Tropical system in the Gulf of Alaska where a formidable system is now. The downstream amplification of the W US ridge and downstream cutoff low should pull Nicole poleward and for the moment the models are over the place on position including the GFS and a strike on the FL panhandle in 8 days....that's a long way off between now and then. The ECMWF suggests it's Matthew that will strike FL in 6 days. I share Thunderbird12's reasoning; I can't dismiss the real possibility that this system may very well be subtropical or post-Tropical given the synoptic features that will be in play given the depth of the cutoff low over the Mid-South late this weekend and early next week. Initially it is expected to move fairly slow across the South before lifting NE.

Rasvar
(Weather Master)
Fri Sep 24 2010 06:30 PM
Re: Matthew Forecast Lounge

With this complex pattern, it may be 48 hours or more before the mystery energy that is seen in the models is shown to be Matthew or from someplace else. I am starting to think that it will be a case of Matthew raining itself out over land (as the NHC track implies) and the flag being taken up by another low pressure system. South Florida may end up being the focal point the middle of next week as I think that any development is more likely to be further east than what the models are showing. However, it really seems to be just as clear as Mississippi mud right now.

WesnWylie
(Weather Guru)
Fri Sep 24 2010 07:18 PM
Re: Matthew Forecast Lounge

The latest (18z) GFS shows what would be Nicole making landfall in South Florida, crossing over the state, moving into the Northern GOM, and then inland over Texas. This would be very interesting if this were to actually occur. Of course, the next run of the GFS will likely show something different, but what the models continue showing is that the Tropics will continue to stay active for the next few weeks.


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