2015 Global model runs discussion

[Yellow Evan]

Honestly I'm in the minority, but I think the GFS has made some progress with it's upgrade. It's cut back on false alarms somewhat, but then again it's gotten worse with overdoing intensity of typhoons.

ECMWF has also become more bullish due to increased resolution and it's low bias in genesis has turned into a high one. It's almost as if the ECMWF/GFS have flipped flopped roles from years past.

Yeah that is a good take. I think the roles have reversed to some degree.

I am interested to see how the GFS does in the SW Caribbean now late in the year. It has been abysmal in that area last several years spinning up phantom storms for several runs in a row. I hope they improved that because that was extremely annoying.

I don't recall seeing too many phantom storms in June this year compared to last.

[gatorcane]

12Z GFS develops the NW Caribbean system starting around 200 hours and has it in the GOM doing a loop in the long-range. The timeframe is coming in.

300 hours below:

[LarryWx]

12Z GFS develops this around 240 hours and has it in the GOM doing a loop in the long-range.

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

[blp]

12Z GFS develops this around 240 hours and has it in the GOM doing a loop in the long-range.

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

What is the Climo for El Nino years. I always thought the W. Caribbean mostly shutdown during October El Nino years. I remember Ida in 2009 but don't remember others.

I am still skeptical the shear will let up to allow this to happen.

[NDG]

12Z GFS develops this around 240 hours and has it in the GOM doing a loop in the long-range.

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

Larry, I know you have been preaching this for while based on analogs, the UL environment will have to really become favorable for any development in the Caribbean to be much of a US threat.
It will be interesting if your forecast comes to fruition or not

[LarryWx]

12Z GFS develops this around 240 hours and has it in the GOM doing a loop in the long-range.

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

What is the Climo for El Nino years. I always thought the W. Caribbean mostly shutdown during October El Nino years. I remember Ida in 2009 but don't remember others.

I am still skeptical the shear will let up to allow this to happen.

To a large extent during strong El Nino years, I agree. However, it seems that 2nd year strong El Nino's (like 2015) may tend to buck the
trend.

[LarryWx]

12Z GFS develops this around 240 hours and has it in the GOM doing a loop in the long-range.

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

Larry, I know you have been preaching this for while based on analogs, the UL environment will have to really become favorable for any development in the Caribbean to be much of a US threat.
It will be interesting if your forecast comes to fruition or not

Duly noted.

[blp]

With as bad as the models have been at day 5, much less at day 10, I think that most know to take these with a huge grain. Also, the GFS has a recent history of false geneses in the W. Caribbean. However, climo does start favoring the W. Caribbean for genesis during the last few days of Sep. and especially during the first half of Oct. Considering climo and being that the last four runs (at least) of the GFS and the last two runs (at least) of the Euro have at least suggested TC development there ~9/25-7, it wouldn't surprise me if that area into the Gulf will become an area being watched closely as we approach the end of Sep/early Oct.
In addition, I have an extra interest in the western basin from now through ~10/15 because I've noted since early August based on three 2nd year strong+ El Nino analog seasons the hint of a potential Conus H threat centered on the NE Gulf/NW FL from late Sep. through ~10/15.

What is the Climo for El Nino years. I always thought the W. Caribbean mostly shutdown during October El Nino years. I remember Ida in 2009 but don't remember others.

I am still skeptical the shear will let up to allow this to happen.

To a large extent during strong El Nino years, I agree. However, it seems that 2nd year strong El Nino's (like 2015) may tend to buck the
trend.

Thanks for your time to research this.

[gatorcane]

Thanks Larry, the ECMWF is also showing something so this makes me think the GFS is not showing a phantom system this time.

[Alyono]

for laughs, see what the MU is doing in the CPAC. Has a slow moving Iniki and then breaks a piece off and rockets it toward the NW or Canada. This is after it has another hurricane that starts forming in 4 days threatening the islands

[gatorcane]

18Z GFS has development in the NW Caribbean but the timeframe seems to have pushed out some on this run and still shows it in the very long-range.

[gatorcane]

The GFS looks to be not that enthusiastic about the NW Caribbean system in the overnight runs but the ECMWF shows a tropical storm heading NE into Florida from the NW Caribbean and the CMC also shows the system at 240 hours forming in the NW Caribbean. The GFS hits Florida from the east though in the long-range:

ECMWF:


GEM:


GFS:

[gatorcane]

The ECMWF has the area of disturbed weather that eventually forms into a tropical storm moving off the coast of Honduras in around 5 days now so it is bringing in the timeframe. My confidence is growing we will get some area of disturbed weather to form over the NW Caribbean / Yucatan / Belize area starting in the Thu.-Fri. timeframe. Whether it eventually forms into something of significance is the question.

[gatorcane]

From what I can tell, the GFS doesn't develop the NW Caribbean system in the last couple of runs because it keeps the vorticity over land. In this map below, you can see the vorticity inland, just west of Belize where it moves NW. If the GFS moves this vorticity over the NW Caribbean instead like the ECMWF and CMC, one would think we would see development. Very curious what the next set of runs look like for this potential NW Caribbean system for next weekend.

The big difference between the GFS and ECMWF is that while both the GFS and ECMWF pinch off a cut-off low from a short-wave moving east over the Great Lakes next week, the ECMWF keeps this cut-off low around much longer and that allows for a weakness in the ridge over the SE United States and Gulf, allowing the NW Caribbean system to move N and then NE between this cut-off low and a ridge over Central Caribbean and far SW Atlantic.



ECMWF 500MB Heights at 216 hours showing cut-off low hanging around the SE United States:

[CourierPR]

Gatorcane, do you think something will form in the NW Caribbean?

[Weatherwatcher98]

Close to That time of year for home brew

[Weatherwatcher98]

Nice naked twist in the Gulf west of Tampa

[Sanibel]

Talk about an entire basin that's just scrubbed clean of any tropical development.

[blp]

I am starting to bite a little on something possibly getting going in the SW Carribean. The MJO on both the Euro and GFS are trending stronger toward that region first days of October. I think the problem right now is that it will be complicated setup with gensis possibly coming from EPAC crossover, frontal boundary or SW Carribean based . Could end up being one broad gyre that never does anything significant.

[Rgv20]

12zECMWF Ensembles showing a lot of sub 1005mb lows in the SW/SC GOM by day 10....the control run has a 998mb low in the NW GOM. In the longer range the control run weakens the low and moves it SW toward Mexico.