Seasonal Indicators (Beyond Day 16): Instability / SST's / MSLP / Steering / Sal

[TheStormExpert]

Wxman57 did mention that the NW Caribbean was where he thought things would wake up first in the Atlantic.

[SFLcane]

Tempted to say this but the Caribbean,Gulf Bahamas region are open for business even the main development region to some extent. Once we get ride of this SAL "watch out ".

[TheStormExpert]

Yes shear has most definitely dropped to non-inhibiting levels towards tropical development.



Now all we need is for the SAL to decrease a good deal at least and instability should come up some though I still expect it to be below average in the Tropical Atlantic this season.

[RL3AO]

That wave near Cape Verde is very large and is bringing moist air from the south up behind it. It might be a rather effective sacrificial wave.

[Hammy]

That wave near Cape Verde is very large and is bringing moist air from the south up behind it. It might be a rather effective sacrificial wave.

Is the SAL basically the only think preventing development at this point?

[RL3AO]

That wave near Cape Verde is very large and is bringing moist air from the south up behind it. It might be a rather effective sacrificial wave.

Is the SAL basically the only think preventing development at this point?

I don't think anything can develop east of 50W right now. Water is kinda cool and there is a bunch of sinking air. Any development in the next couple weeks will be near the islands or in Caribbean/Bahamas.

[TheStormExpert]

Yes SST's throughout the eastern half of the Tropical Atlantic are Below Average and not warm enough or just barely warm enough to support a Tropical Cyclone or development of any sorts. Even with the NAO recently dipping negative it did not help increase SST's.

[gatorcane]

That wave near Cape Verde is very large and is bringing moist air from the south up behind it. It might be a rather effective sacrificial wave.

Is the SAL basically the only think preventing development at this point?

Another thing is mid-level dry air. Even in 2013 I recall low shear across much of the Atlantic with warmer than normal SSTs but yet it was a below average season. This mid-level dry air is widespread across the Atlantic basin. Models out through a week do not show any improvement so waves just dry up and then once they enter Caribbean cannot develop due to shear. We would expect to see less mid-level dry air as we head into early August but my feeling is we may need to wait another 4-5 weeks to get a named system of tropical origin in the Atlantic.

[Ntxw]

That wave near Cape Verde is very large and is bringing moist air from the south up behind it. It might be a rather effective sacrificial wave.

Is the SAL basically the only think preventing development at this point?

Another thing is mid-level dry air. Even in 2013 I recall low shear across much of the Atlantic with warmer than normal SSTs but yet it was a below average season. This mid-level dry air is widespread across the Atlantic basin. Models out through a week do not show any improvement so waves just dry up and then once they enter Caribbean cannot develop due to shear. We would expect to see less mid-level dry air as we head into early August but my feeling is we may need to wait another 4-5 weeks to get a named system of tropical origin in the Atlantic.

Higher than normal pressures the cause? i see it in the drier than normal precipitation rates using July 1-12 reanalysis. Though not the extent it was in 2013.

[TheStormExpert]

Mid-Level Dry Air at the moment is an issue, but of course there is so much Dry Stable Air/SAL out there at the moment so we will see if this changes in the coming weeks.



Like Wxman57 said, he is not seeing a big Cape Verde season coming but of more concern is the waves that can actually survive and track all the way to the Western Caribbean, Gulf of Mexico, or even off the SE U.S.(if the Bermuda High isn't too strong). This is where the real action will take place, and as we've seen years past those systems are far more likely to affect land.

[Ntxw]

:uarrow: Mid-Level Dry Air at the moment is an issue, but of course there is so much Dry Stable Air/SAL out there at the moment so we will see if this changes in the coming weeks.

That's certainly true but mostly for the lower levels, SAL can be overcome with vigorous waves. Mid level dry air is more a product of sinking air.

[ninel conde]

I dont expect july to be super active but if i were looking for aug/sept to be active i would expect at the very least to see waves survive across the atlantic with at least some convection. Going well past day 16 to next season its beginning to look like another very dry winter in cali with a big trof in the east. To see a break in this multi-year pattern i would expect first to see the drought in california to end. I should have realized this season when the super el nino didnt result in cali drought busting rain that something was wrong.

[tolakram]

I dont expect july to be super active but if i were looking for aug/sept to be active i would expect at the very least to see waves survive across the atlantic with at least some convection. Going well past day 16 to next season its beginning to look like another very dry winter in cali with a big trof in the east. To see a break in this multi-year pattern i would expect first to see the drought in california to end. I should have realized this season when the super el nino didnt result in cali drought busting rain that something was wrong.

They are all surviving just fine and developing in the EPAC. Why do you claim waves are not surviving?

I don't think the 'big trof in the east' has as that big an influence on Atlantic and US weather patterns. As can be seen looking at archived weather maps the 'trof in the east' is a fairly regular feature.

[tolakram]

CIMSS product loops.

SAL: http://tropic.ssec.wisc.edu/real-time/s ... E5new.html

Mid-level Water Vapor: http://tropic.ssec.wisc.edu/real-time/s ... d5new.html

Upper-level Water Vapor: http://tropic.ssec.wisc.edu/real-time/s ... i5new.html

Sat loop: http://tropic.ssec.wisc.edu/real-time/s ... l5new.html

All from this page: http://tropic.ssec.wisc.edu/real-time/salmain.php?&prod=truecol&time=

[srainhoutx]

I continue to see the GEFS Ensemble Members suggesting the possibility of TC Genesis across the NW Caribbean and the Gulf in the longer range. Both the 00Z and 06Z runs are indicating the potential of a more favorable pattern developing as we end July and begin August as mean sea level pressures lower and vorticity potential increases.

00Z:


06Z

[TheStormExpert]

This was also posted in the ENSO Thread but I feel it could be something to discuss here while we wait for what the rest of the 2016 season has to offer.

What effects would a Neutral state ENSO have on the Atlantic when compared to a La Niña state ENSO?

 https://twitter.com/philklotzbach/status/753945406514397184

[Ntxw]

It means local conditions and indices in the Atlantic will have bigger influences since there will be little outside influence. Weather patterns and preconditioning even more a player. The past two neutral seasons (2012 and 2013) were complete opposites. Volatile forecast.

[chaser1]

I dont expect july to be super active but if i were looking for aug/sept to be active i would expect at the very least to see waves survive across the atlantic with at least some convection

I agree to a point, and I do believe that we will soon begin to see some far more impressive waves begin to roll off Africa somewhere in the 1-3 week time frame. The only exception I might take comes from recalling years where wave after wave rolled off the W. coast of Africa, just to dissapear as they entered repressed E. Atlantic conditions, or perhaps to seemingly dive SW. into a southward repressed ITCZ. However, that wasnt to say that those "pouches" of vorticity didn't re-emerge farther west where pressures might have been lower and the ITCZ bulged further north. Ironically, it could well be those systems that are unable to develop further east that might well reappear east of the Lesssor Antilles which might be cause for development of tropical systems that would have otherwise developed and possibly picked up by some mid Atlantic trough. These same repressed and 'under the radar" waves, might well be an increased cause of Caribbean, Mexican, and potentially U.S. landfalls as we move into the meat of the season, a few weeks from now.

[tolakram]

 https://twitter.com/philklotzbach/status/753950725508431873

[hurricanehunter69]

Maybe we can think of this wave in the far eastern Atlantic as a snow plow ( dry air/SAL plow). Or...the engine of the 2016 cape verde wave train? also...check out that cyclonic motion in the Gulf? http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html