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

[chaser1]

Yeah your right, seems as if the overall Atlantic basin shows an expanding area of high SST anomalies! Though I'm not sure, does it seem as if the waters off the northeast U.S. and Canadian maritime have cooled during the same period as compared to a month or two ago?

On an altogether different note, notice those few "hot spots" across the entire globe (especially the area depicted by dark red off the East coast of S. America!?). Is it odd to anyone else that in all localized area's where the very highest SST anomalies are appearing, they're primarily surrounded by pockets of average to cooler than average anomalous SST's? Kind of hard to wrap my head around why that would occur. Could that be the result of some type of offshore industrial or significant underground volcanic activity?

[cycloneye]

@RyanMaue
As hurricane season progresses, we look into the far Tropical Atlantic for tropical waves. African dust outbreaks keep a lid on development

 https://twitter.com/RyanMaue/status/877603736247427073

[RL3AO]

@RyanMaue
As hurricane season progresses, we look into the far Tropical Atlantic for tropical waves. African dust outbreaks keep a lid on development

Maybe my memory is failing, but I seem to remember a lot more oranges and yellows (on his color bar) getting down into the MDR latitudes (10 to 20N) with SAL outbreaks last year.

[chaser1]

@RyanMaue
As hurricane season progresses, we look into the far Tropical Atlantic for tropical waves. African dust outbreaks keep a lid on development

Maybe my memory is failing, but I seem to remember a lot more oranges and yellows (on his color bar) getting down into the MDR latitudes (10 to 20N) with SAL outbreaks last year.

I was thinking the same thing. Seemed as if recent year SAL outbreaks were both, more expansive including further south AND did not disperse nearly as quickly as that loop had projected. Of course we're still in mid June and "Saharaan Appreciation Month" is quickly approaching lol. Time will tell whether larger and denser outbreaks will occur as we get into July. I wonder what would be the overall cause "if" it turns out that SAL outbreaks end up further north, less dense, and dispersing faster? Aside from whether recent spring patterns were a cause of greater precip. over western regions of Africa that could result in less dust, i suppose the other main factor would largely be a result of the orientation and strength of the southern edge of 750mb-500mb level Easterly trades coming off the African coastline?

[BigA]

@RyanMaue
As hurricane season progresses, we look into the far Tropical Atlantic for tropical waves. African dust outbreaks keep a lid on development

Maybe my memory is failing, but I seem to remember a lot more oranges and yellows (on his color bar) getting down into the MDR latitudes (10 to 20N) with SAL outbreaks last year.

I was thinking the same thing. Seemed as if recent year SAL outbreaks were both, more expansive including further south AND did not disperse nearly as quickly as that loop had projected. Of course we're still in mid June and "Saharaan Appreciation Month" is quickly approaching lol. Time will tell whether larger and denser outbreaks will occur as we get into July. I wonder what would be the overall cause "if" it turns out that SAL outbreaks end up further north, less dense, and dispersing faster? Aside from whether recent spring patterns were a cause of greater precip. over western regions of Africa that could result in less dust, i suppose the other main factor would largely be a result of the orientation and strength of the southern edge of 750mb-500mb level Easterly trades coming off the African coastline?

I would hypothesize that the main contributor to the (potentially) weaker SAL outbreaks is the somewhat weaker than normal easterly winds coming off the African coast around 15-25 North during the last month.


Rainfall amounts may also affect dust outbreaks, though there is some uncertainty whether dust outbreaks are more related to rainfall during the current year or the previous year. Regardless, it is well-documented that Sahel precipitation from June-September is positively correlated Atlantic hurricanes that year (e.g., Landsea and Gray 1992).

Currently, the African Intertropical Front (ITF) is substantially to the north of it's climatological mean position. Thus, the moist, tropical air and associated precipitation are also north of the mean position. This may reduce the severity of SAL outbreaks, but I am not certain.

http://www.cpc.ncep.noaa.gov/products/i ... itcz.shtml

For what it's worth, the NMME predicts substantially above-normal Sahel precipitation during July-September, while the ECMWF and UKMET climate models predict near-normal precipitation in the western Sahel (though the UKMET has above normal in the eastern Sahel).

Worth keeping an eye on as we head toward the MDR part of season.

[Steve820]

I wonder if climate change could be responsible for the recent streak of years with 3 named storms in the Atl by 6/20. Before 2012 the two occurrences (1887 and 1959) were very spread out. And seeing a MDR storm this early as well as Cindy being active at a similar time kind of freaks me out about what the rest of the season might look like (Aug to Oct especially)

It's most likely observations that are leading to it. Storms like Arlene (2017) simply weren't caught in the pre-satellite era, and often weren't considered tropical storms before the 1990s/2000s. You could even argue a hurricane like Alex last year might not have been caught in a pre-satellite era. Any ship report of a hurricane in January would have likely been laughed at.

That's possible. Especially weak out-to-sea storms like Arlene would have never been detected way back then. In fact, any Alex repeats back in pre-satellite era that were reported by ships might have been mistaken for just a "big storm" because no one would take seriously a hurricane forming before May or June.

[gatorcane]

Africa continues to be very active:

[Hammy]

Looks like a major change from the last several years. Good chance of the MDR being more active this year?

[Hurricaneman]

Africa continues to be very active:

This could be really be bad news as the season goes on these waves are only going to get stronger and I wouldn't be surprised if we see a few long track hurricanes hit the US

[Yellow Evan]

MJO is currently in that region.

[AutoPenalti]

Africa continues to be very active:

Holy mother of wave trains...

[Nimbus]

Africa continues to be very active:

The wave train looks a little further north than usual this June.
Bret and the current sharp wave approaching South America seem to have made it through the SAL and shear intact.
Hopefully the patterns change before Cape Verde season.
All it takes is a strong TUTT developing at the right time.

[RL3AO]

:uarrow: MJO is currently in that region.

The MJO is very very weak right now.




There's enhanced convection over Africa right now, but it doesn't appear to be tied to any equatorial wave mode.



There doesn't really appear to be a strong wave mode signal anywhere globally right now.
http://i.imgur.com/0wVhwFX.png

However, maybe some evidence of a favorable Atlantic MJO in a couple weeks.

http://i.imgur.com/UVkN85i.png

[cycloneye]

Is EPAC's turn to have activity in the next 2 weeks.

[RL3AO]

:uarrow: Is EPAC's turn to have activity in the next 2 weeks.

Yes. Epac should be rocking the next couple weeks.

[TheStormExpert]

:uarrow: Is EPAC's turn to have activity in the next 2 weeks.

Yes. Epac should be rocking the next couple weeks.

I still don't see the type of activity we saw last July over in the East Pacific.

[Kingarabian]

:uarrow: Is EPAC's turn to have activity in the next 2 weeks.

Yes. Epac should be rocking the next couple weeks.

I still don't see the type of activity we saw last July over in the East Pacific.

That's because it's not July yet and the outbreak is just getting started.

[cycloneye]

@AndyHazelton
The CFS weeklies show a sharp uptick in precip out of the MDR around week 3, so maybe we just have to wait for the climo to tick up.

 https://twitter.com/AndyHazelton/status/878644195564638208




Replying to @AndyHazelton
EPS Weeklies show the same after July 5th, continuing into August

 https://twitter.com/TropicalTidbits/status/878644695940911104

[MetroMike]

:uarrow: Is EPAC's turn to have activity in the next 2 weeks.

The EPAC is rife with cooler SST this year. Agree that it will not be as active in that region this year.


Yes. Epac should be rocking the next couple weeks.

I still don't see the type of activity we saw last July over in the East Pacific.

[Hammy]

Do the MJO and Kelvin waves have any impact on possibly distorting model outputs for the following months' rainfall? the CFS seems like it's backed off significantly in rainfall (and potential tropical activity) in recent runs.