2017 indicators: SST's / MSLP / SAL / Steering / Instability

[hurricanehunter69]

Wow, what a strong monsoonal trough just sitting in the right spot. we're definitely witnessing some strong consistent convergence going on there. And then surrounded by a large body of anomalously warm water. Good Luck

[RL3AO]

2017 is 12th Atlantic hurricane season w/ 2 MDR (S of 23.5°N, E of 75°W) TCs before 8/1. Most yrs ended up active hurricane seasons.

Other years w/ 2 MDR TCs prior to 1 August were: 1887, 1901, 1926, 1933, 1944, 1966, 1979, 1995, 1996, 2005 & 2013. 2013 only quiet season.

 https://twitter.com/philklotzbach/status/887083057152491520



 https://twitter.com/philklotzbach/status/887083395007860737

[JPmia]

https://www.wunderground.com/cat6/tropi ... es-islands

"Don is likely to be the second tropical storm to affect the Lesser Antilles Islands this year. According to NOAA’s Historical Hurricanes site, this would be the first year on record for the islands to see two tropical storms before August 1. There were two other years that came close: in 2005, Hurricane Emily passed though the islands on July 14, and the tropical depression that would become Hurricane Dennis passed through on July 4. In 1933, a tropical depression passed though the islands on July 14, and a tropical storm hit on July 25. It should give no one comfort that these were the two busiest Atlantic hurricane seasons on record!"

[Alyono]

Klotzbach is using the strangest definition of MDR ever

I've never seen it extended to 23.5N. Usually only goes to 20N. I have seen it extended to the western Caribbean, which is the one I have always used

[PTrackerLA]

https://www.wunderground.com/cat6/tropical-storm-don-forms-near-lesser-antilles-islands

"Don is likely to be the second tropical storm to affect the Lesser Antilles Islands this year. According to NOAA’s Historical Hurricanes site, this would be the first year on record for the islands to see two tropical storms before August 1. There were two other years that came close: in 2005, Hurricane Emily passed though the islands on July 14, and the tropical depression that would become Hurricane Dennis passed through on July 4. In 1933, a tropical depression passed though the islands on July 14, and a tropical storm hit on July 25. It should give no one comfort that these were the two busiest Atlantic hurricane seasons on record!"

That's a concerning correlation to the two most active seasons on record. We should all be well rested for August-October I'm afraid .

[Hammy]

Klotzbach is using the strangest definition of MDR ever

I've never seen it extended to 23.5N. Usually only goes to 20N. I have seen it extended to the western Caribbean, which is the one I have always used

Wouldn't that make this that much more uncommon if he's expanded it north?

[WeatherEmperor]

https://twitter.com/MJVentrice/status/8 ... 7440238593


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[WeatherEmperor]

https://twitter.com/MJVentrice/status/8 ... 8279937025

Very interesting.....


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[srainhoutx]

The developing Convectively Coupled Kelvin Wave near the Indian Ocean in the Week 2 time frame is clearly seen on Mike Ventrice's page. By Week 3 it expands to just beyond the Dateline heading East.

[Ntxw]

Looking at background forcing (200mb CHI) by the end of the month to early August does look more favorable for Western Atlantic activity.

[Steve]

If that is the case, which is exactly what my caveat was for anything of substance before 6-7 weeks, then it probably gets quiet after that pulse and before the peak. Could end up being a much higher NS year than I thought.

[Ntxw]

If that is the case, which is exactly what my caveat was for anything of substance before 6-7 weeks, then it probably gets quiet after that pulse and before the peak. Could end up being a much higher NS year than I thought.

Names will definitely be up there. At some point it will have to produce ACE or the ratio will be low. 2013 is notorious for a bad ratio while 2004 is the opposite

[Steve]

If that is the case, which is exactly what my caveat was for anything of substance before 6-7 weeks, then it probably gets quiet after that pulse and before the peak. Could end up being a much higher NS year than I thought.

Names will definitely be up there. At some point it will have to produce ACE or the ratio will be low. 2013 is notorious for a bad ratio while 2004 is the opposite

That's exactly right. I don't ever like seeing anything referencing 2004, 2005, 1969 or 1933. Seems those years are popping up in various analysis though this seems to be a combination year where there are elements of many different seasons rather than being one that looks like it's happened before. For instance there are years with very similar SSTA profiles to what we have now. There are years that correlate with continental temperature and precipitation profiles. And years where ridging in the Atlantic has been similar. I think 11-13 was a good point of reference for Named Storms going back to April and May with the uncertainly of what the El Nino was going to do. I think you had it pegged as a likely Modoki pretty early on. And obviously that's sort of where we are in the Pacific. I just don't wonder since this year they are naming systems they may have ignored in other years if we don't exceed 15. If we get nothing after Don until that next KW/MJO Pulse Ventrice thinks happens in early-mid August, we could be at F or G before the peak run. They might be mostly weaker systems, but still. It seems like the ACE will be at least closer to average if we even get a couple of majors, enough hurricane days and maybe a couple of systems bombing out off the SE US East Coast as we've seen in several of the last few years. I don't know. But I'd probably be more surprised at this point if the season ends up under performing rather than over performing

[TropicalAnalystwx13]

[NDG]

 https://twitter.com/MichaelRLowry/status/887430357255106560

[JPmia]

 https://twitter.com/MichaelRLowry/status/887430357255106560

The MDR is wide open on that graphic. Also, look at the anomalous low shear from the NE Carib. Islands, Bahamas, FL, and to the GOM.

[tarheelprogrammer]

So, with MJO moving into the Pacific in early August that should shut down much of the Atlantic then right?

[Kingarabian]

[tweet]https://twitter.com/MichaelRLowry/status/887430357255106560[/weet]

Those graphics line up well with CIMSS charts - except in the Caribbean, where westerly shear remains pretty vicious.

[RL3AO]

So, with MJO moving into the Pacific in early August that should shut down much of the Atlantic then right?

"Shut down" is probably too strong of a phase. The worst large scale conditions will probably be during the remainder of July with a probable shift to a favorable pattern around the 2nd week of August.

[TheStormExpert]

Then there is this.

 https://twitter.com/philklotzbach/status/887507388995035137