Global model runs discussion

[HurricaneWarning92]

From Dr Jeff Masters:

Most of the models predict the development of a tropical depression or strong tropical disturbance 5 - 6 days from now off the coast of Africa.

If it does verify, let me guess... another recurve out to sea...

[CourierPR]

From Dr Jeff Masters:

Most of the models predict the development of a tropical depression or strong tropical disturbance 5 - 6 days from now off the coast of Africa.

If it does verify, let me guess... another recurve out to sea...

Watch the Caribbean in the next ten days.

[RachelAnna]

I just can't seem to get excited about models unless they are bringing some rain to Texas.

[ronjon]

Huge western caribbean storm develops in 8-9 days and moves north into the GOM then northeast into the FL panhandle on the 18z GFS run.

18z GFS loop

[cycloneye]

I am posting the graphic of where and when it starts to develop in the Western Caribbean. Also, the model has a wave trying to develop in the MDR.



Saved image.

[psyclone]

that would certainly wake the board up. and a storm forming in that region and taking that sort of parabola is believable based on climo and the trends this year.

[BigA]

I think it is reasonable to say that seven to nine days from now there will be a monsoon trough in the western Caribbean. What forms from it and where a storm would go are still totally unknown but it is worth mentioning that most of the GFS runs showing development send the system north, not west. Still in the realm of the unknown, though, if not quite fantasy land.

[RL3AO]

The planet seems to do a good job at keeping itself in balance and the West Pac is slow and the EPac is non-existent right now. Sooner or later something has to give in the Atlantic.

[Gustywind]

From Dr Jeff Masters:

Most of the models predict the development of a tropical depression or strong tropical disturbance 5 - 6 days from now off the coast of Africa.

Any link about that Cycloneye? From wunderground?
Thanks

[cycloneye]

From Dr Jeff Masters:

Most of the models predict the development of a tropical depression or strong tropical disturbance 5 - 6 days from now off the coast of Africa.

Any link about that Cycloneye? From wunderground?
Thanks

Yes from there. I dont post the link as it has a message board with many blogs and that is one of our rules,not to post links to other message boards.

[HurricaneFan]

[quote="cycloneye"]:uarrow: I am posting the graphic of where and when it starts to develop in the Western Caribbean. Also, the model has a wave trying to develop in the MDR.



So what do the models say about the pattern in that time for the Tropical Wave in the MDR?
Will it make it to the Caribbean or will it go out to sea?

[Gustywind]

Thanks for this precious info, i understand

[rainstorm]

would be an exciting way to end sept.

[Emmett_Brown]

IF the model consensus of bringing down one big sfc high into the NE US and the 12Z GFS in bringing down a 2nd one were to verify, then the teleconnection would be for above avg. activity down below in the W. Caribbean. GOM, and/or off the east CONUS coast. Look at past seasons for proof of this. So, the 2nd half of SEP is liable to be very active in the western basin. Often times in mid to late Sep. and early to mid Oct., it is the strength of the surface highs that come into the NE US that determine how active it gets below them near the CONUS. That is because there foten is a tendency to balance out high pressure to the north with concentrated low pressure below that high pressure due to sfc convergence. JB has talked about this many times. 1947 is a very good example. Look at old surface wx maps from 9-10/1947 and check out how active it was in those areas from mid-Sep to mid-Oct.

Folks,
This is a followup to the post I made above prior to the 12Z Euro release. Since then, the 12Z Sat. Euro , 18Z Sat. gfs and 0Z Sun. gfs are being even more insistent on strong and persistent sfc high pressure over the NE US for the period ~9/17-9/23. When sfc high pressure does this, there is a good bit higher than average potential of a TC existing (either from a homegrown system or from one moving into that area) below it near the SE US/FL/E GOM due to a tendency for sfc pressures to fall and concentrate below persistent big highs aided by sfc convergence. Moreover, big persistent highs like this often act as blocks and normally prevent easy recurves/increase the chance for an existing TC to landfall over the SE US. History/analogs tell me all of this.

Stay tuned, folks. There are ominous signs that tell me that the season is likely going to get a good bit more interesting for the CONUS around the 9/18-24 period for the reason noted. IF the model consensus is close to being correct for 9/17-24, we're looking at about as strong and persistent a sfc high pressure pattern over the NE US as one would expect to see in Sep. I would be surprised to see the CONUS not get hit during or near this period. The 0Z GFs actually shows a 9/23 TC landfall over S FL fwiw as noted by the poster above (not at all surprising..I think we're going to see more runs like this in the days to come). This would be a totally different pattern from what has been experienced for much of the season to this point. The cries of "season cancel will likely become a thing of the past.

LarryWx, given the 500 mb steering pattern that the 18z GFS is predicting over the western Caribbean, wouldn't any storm that form generally by pushed W into central America?

[bigdan35]

This is where the gfs has storm ending up



Uploaded with ImageShack.us

[weatherwindow]

Will surface highs in the NE not allow troughs to swing down and scoop up any hurricanes?

The upper patterns that allow for strong and persistent NE surface highs are ridgey. Therefore, there often are no troughs then dipping down to near the SE US to scoop up TC's.

........FOR THE BOARD...Have two rather broad questions. First, we have been discussing, for perhaps a month, a pending pattern change. There has been increasing model support and there are certainly precedents for such a change. How would you assess your confidence in the strength, placement, and timing of the ridge? IMHO,if anything, the gfs tends to understate ridge strength. Unfortunately, it also tends to dispense with ULL/trofs prematurely. The evolution of the projected ridging is going to be strongly dependent on maria's track and speed. The latest nhc track brings maria to a crawl for two days prior to accelerating in recurvature. Do you see this as a significant factor? My second question touches on the issue of persistence. Do we see a dynamic ridge at 500mb supported to 200 mb which would tend to rebuild at steering level over the next few weeks?..Or do you see it as more transient. As you noted, this presence or absence of this feature will be a determining factor in October/November cyclogenesis. A persistent east coast ridge, in concert with a strengthening La Nina, could result in a memorable late season for florida and cuba.

[BigA]

00Z GFS continues with tropical development in the western Caribbean in a bit over a week. 4 of the last 5 runs have shown this.

[ROCK]

0z GFS is also more west than prior runs clips the Yucatan and making its way into the Central / Western GOM.....can we say drought killer.....hope so...

[LarryWx]

IF the model consensus of bringing down one big sfc high into the NE US and the 12Z GFS in bringing down a 2nd one were to verify, then the teleconnection would be for above avg. activity down below in the W. Caribbean. GOM, and/or off the east CONUS coast. Look at past seasons for proof of this. So, the 2nd half of SEP is liable to be very active in the western basin. Often times in mid to late Sep. and early to mid Oct., it is the strength of the surface highs that come into the NE US that determine how active it gets below them near the CONUS. That is because there foten is a tendency to balance out high pressure to the north with concentrated low pressure below that high pressure due to sfc convergence. JB has talked about this many times. 1947 is a very good example. Look at old surface wx maps from 9-10/1947 and check out how active it was in those areas from mid-Sep to mid-Oct.

Folks,
This is a followup to the post I made above prior to the 12Z Euro release. Since then, the 12Z Sat. Euro , 18Z Sat. gfs and 0Z Sun. gfs are being even more insistent on strong and persistent sfc high pressure over the NE US for the period ~9/17-9/23. When sfc high pressure does this, there is a good bit higher than average potential of a TC existing (either from a homegrown system or from one moving into that area) below it near the SE US/FL/E GOM due to a tendency for sfc pressures to fall and concentrate below persistent big highs aided by sfc convergence. Moreover, big persistent highs like this often act as blocks and normally prevent easy recurves/increase the chance for an existing TC to landfall over the SE US. History/analogs tell me all of this.

Stay tuned, folks. There are ominous signs that tell me that the season is likely going to get a good bit more interesting for the CONUS around the 9/18-24 period for the reason noted. IF the model consensus is close to being correct for 9/17-24, we're looking at about as strong and persistent a sfc high pressure pattern over the NE US as one would expect to see in Sep. I would be surprised to see the CONUS not get hit during or near this period. The 0Z GFs actually shows a 9/23 TC landfall over S FL fwiw as noted by the poster above (not at all surprising..I think we're going to see more runs like this in the days to come). This would be a totally different pattern from what has been experienced for much of the season to this point. The cries of "season cancel will likely become a thing of the past.

LarryWx, given the 500 mb steering pattern that the 18z GFS is predicting over the western Caribbean, wouldn't any storm that form generally by pushed W into central America?

Not necessarily because that is pretty far down in lat.

[rainstorm]

06 gfs has lost any meaningful tropical development through 15 days. ridge isnt all that impressive either.