ATL: HERMINE - Models

[LarryWx]

the 12Z ECMWF develops a cutoff low near Bermuda again and it might create just enough of a weakness to lift the weak surface low north out of the Bahamas. The GFS nor CMC show this cutoff low. Besides that, the ridge over the Carolinas looks strong. The window is tight and timing would be crucial, if 99l does develop and is positioned a little further west it could get under that Carolina high and move west.

It looks to me that that cutoff low near Bermuda is involved with the remnants of Fiona at the sfc.

[WeatherEmperor]

To summarize we have the following:

Models developing: Canadian, Navgem, Hwrf, Gfs (very little), Jma, Gfdn

Models not developing: Euro, Ukmet, Gfdl

Knowing all this, Nhc increased development chances to 60%

[chaser1]

Looking at this 192hr EURO, i'm just not really seeing any weakness or much evidence that any support would allow decent fronts to penetrate off of New England at this time. Whether or not 99L does develop, I'm just not seeing how it is not trapped and forced to move seemingly over Florida and into the Gulf. Perhaps by coincidence too, there does seem to be a weak low in the N. Gulf at 240 hr. just south of Louisiana at this time as well. Furthermore, one can plainly see how the orientation of the 594 mid Atlantic high might allow for developed systems to turn "more poleward" as they approach 50W-60W but no where have I seen in this EURO run any significant reason for tropical systems to be recurving into an obvious gap in the ridge. I"m just wondering if (or why) there would be any chance that the EURO might be slightly underscoring mid level pressure heights?

[chaser1]

To summarize we have the following:

Models developing: Canadian, Navgem, Hwrf, Gfs (very little), Jma, Gfdn

Models not developing: Euro, Ukmet, Gfdl

Knowing all this, Nhc increased development chances to 60%

Wait? Last I heard someone had indicated that the UK was on-board with developing 99L, but weakening to a T.S. as it approached landfall over HIspanola. Has that changed on this 12Z run??

[LarryWx]

Looking at this 192hr EURO, i'm just not really seeing any weakness or much evidence that any support would allow decent fronts to penetrate off of New England at this time. Whether or not 99L does develop, I'm just not seeing how it is not trapped and forced to move seemingly over Florida and into the Gulf. Perhaps by coincidence too, there does seem to be a weak low in the N. Gulf at 240 hr. just south of Louisiana at this time as well. Furthermore, one can plainly see how the orientation of the 594 mid Atlantic high might allow for developed systems to turn "more poleward" as they approach 50W-60W but no where have I seen in this EURO run any significant reason for tropical systems to be recurving into an obvious gap in the ridge. I"m just wondering if (or why) there would be any chance that the EURO might be slightly underscoring mid level pressure heights?

I wonder if had Fiona had not existed if 99L wouldn't have moved W into FL on this Euro.

[Alyono]

UKMET is developing late next week

[WeatherEmperor]

To summarize we have the following:

Models developing: Canadian, Navgem, Hwrf, Gfs (very little), Jma, Gfdn

Models not developing: Euro, Ukmet, Gfdl

Knowing all this, Nhc increased development chances to 60%

Wait? Last I heard someone had indicated that the UK was on-board with developing 99L, but weakening to a T.S. as it approached landfall over HIspanola. Has that changed on this 12Z run??

I use this site for Ukmet output:

http://my.sfwmd.gov/sfwmd/common/images ... plots.html

I see nothing on the graphical or text output for 12z

[WeatherEmperor]

UKMET is developing late next week

Can you post your Ukmet source? Perhaps what I am using is no longer reliable

[Yellow Evan]

idk why people would expect this to bomb out over the Bahamas after interacting with Hispanola and with no MJO/CCKW help. I expect the GFS to back off in intensity gradually the past few days, and now it appears to be playing out.

I wonder if this is why proto-90L gets very intense on this run. The MJO might not be doing 99L any favors, but if the pulse does weaken it could aide the next system if pressures in the western Atl basin drop a little.

Perhaps it is simply moving the MJO from the dead circle towards the Atlantic too fast in the long range.

[chaser1]

UKMET is developing late next week

Can you post your Ukmet source? Perhaps what I am using is no longer reliable

Thanks WeatherEmperor, and maybe you and Alyono are talking about the same thing?? From the link you posted, I found this at the bottom:

NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 138 HOURS

FORECAST POSITION AT T+138 : 23.1N 74.8W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 26.08.2016 23.5N 76.3W WEAK LITTLE CHANGE

[Dean4Storms]

When the models are this split and somewhat inconsistent beyond 5 days you'll just need to wait for TC Genesis and even then we might need Recon Obs before the models become better defined with the track and intensity. Right now all we can genuinely get out of the models is that after the NE Carib. gets either a lower end TC or just a TW the system will emerge near the SE Bahamas, from there right now it is a crap shoot!

[chaser1]

That forecast for a weak T.S. to form by UK just east of S. Florida is pretty much in line with where the EURO shows the remaining vorticity of 99L (give or take 12-24hr.'s).

So, albiet weak the UK is also on-board with eventual development of 99L. Hard to imagine that such a robust tropical wave with an evident circulation at some level is going to move all the way across the Atlantic given very dry SAL conditions and marginal to somewhat supressed upper conditions, only to form barely east of Florida. Meanwhile, this is more or less what the GFS is advertising as well.

[WeatherEmperor]

UKMET is developing late next week

Can you post your Ukmet source? Perhaps what I am using is no longer reliable

Thanks WeatherEmperor, and maybe you and Alyono are talking about the same thing?? From the link you posted, I found this at the bottom:

NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 138 HOURS

FORECAST POSITION AT T+138 : 23.1N 74.8W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 26.08.2016 23.5N 76.3W WEAK LITTLE CHANGE

Ooooh I cant believe I missed that lol. Ok so we have to wait a few more days for the Ukmet data to show more

[Siker]

UKMET is an intensifying TS into South Florida. Graphics here:

http://ruc.noaa.gov/hfip/tcgen/

[wxmann_91]

Still seems odd to me that you could have a vort max in the Bahamas this time of year with a relatively moist atmosphere, moderate wind shear, and get minimal development. From what I'm seeing on the simulated IR page, it appears the shear might be a little too much for the small vortex. That being said, anytime you get a disturbance in the Bahamas in late August it's worth watching.

We have reframe our line of thinking... the Atlantic basin is just not a very favorable basin for TC genesis and development. Waves developing into storms are the exception, not the norm. The Pacific basins are much more favorable on average.

[blp]

Here is the graphic. UKMET shows development now in Bahamas as other noted.

[p1nheadlarry]

Still seems odd to me that you could have a vort max in the Bahamas this time of year with a relatively moist atmosphere, moderate wind shear, and get minimal development. From what I'm seeing on the simulated IR page, it appears the shear might be a little too much for the small vortex. That being said, anytime you get a disturbance in the Bahamas in late August it's worth watching.

We have reframe our line of thinking... the Atlantic basin is just not a very favorable basin for TC genesis and development. Waves developing into storms are the exception, not the norm. The Pacific basins are much more favorable on average.

Less land mass at temperate/horse latitudes, lots of water available for heating. It's a giant battery that the Atlantic will never become for several hundred thousand years and more as the plates shift, growing the Atlantic. If you thought climate change would be bad for our neck of the woods, I really feel for other parts of the world.

[jlauderdal]

UKMET is an intensifying TS into South Florida. Graphics here:

http://ruc.noaa.gov/hfip/tcgen/

the ukmet talking the place of the gfs for a south florida strike...another model storm for miami...mosquitos in miami far bigger concern at this point

[Bocadude85]

UKMET is an intensifying TS into South Florida. Graphics here:

http://ruc.noaa.gov/hfip/tcgen/

the ukmet talking the place of the gfs for a south florida strike...another model storm for miami...mosquitos in miami far bigger concern at this point

I wouldn't rule out a tropical storm impact on South Florida. Seems like a reasonable forecast/ guess to me.

[Blown Away]

NHC has bigger tool box than Storm2k... They had 12z Euro run prior to the 2pm update and they still increased 5 day to 60%... Gotta think if they are considering the Euro showing very little and potential future 90L blowing up affecting 99L they would begin lowering 99L's percentages at the 8pm update...