2016 Global Model Runs Discussion (Out to Day 16)

[Blown Away]

Weak shallow systems is what models have seen in the Atlantic basin year after year... We see GFS/Euro bomb out EPAC systems on a regular basis... Not sure how many years must pass before it becomes a trend... Rarely do we see a well developed Atl system in the model runs... Likely the Atlantic will hit the number mark, but it sure does seem the storm quality has dropped significantly for near a decade... BOC & N Atl have been the breeding grounds... Just a very amateur observation...

[tarheelprogrammer]

So far GFS coming in weaker. About to cave to ECMWF and CMC?

[TheAustinMan]

Weak shallow systems is what models have seen in the Atlantic basin year after year... We see GFS/Euro bomb out EPAC systems on a regular basis... Not sure how many years must pass before it becomes a trend... Rarely do we see a well developed Atl system in the model runs...

That's what we should expect. The Atlantic is traditionally the Northern Hemisphere's third most active tropical cyclone basin, behind the Western and Eastern Pacific. Why are model storms of great importance? Better to have an intense storm on the models that has the potential to impact civilization not materialize than materialize. And sure there's been plenty of instances where the models have indicated strong systems in the Atlantic in the past few years - that's where the "phantom storm" fame comes from. I can note Erika last year: it was shown to be quite intense on the models, and how did that turn out? There's also this from the GFS ensembles last mid-October. Sheer number of "strong model hurricanes" should not be a metric by which to judge the activity of a hurricane season. Besides, the majority of tropical cyclones are the weak shallow systems you mention, so if we see a greater proportion of those, that would be accurate and would indicate the models are becoming more realistic and improving with time.

I don't want to be completely off topic though, so here's the mid-level RH on the GFS 00z run for this Cape Verde system out to 192 hours. The "pouch" of moisture associated with the disturbance is trying it's best to fuel the system, and even has the aid of a sort of sacrificial high amplitude wave ahead of it to moisten the region a bit, but doesn't appear to be cohesive enough to keep out the onrush of drier air from the east, at least for now.

[tarheelprogrammer]

GFS says what storm? LMAO completely caved in to the other models. Phantom storm it seems. The Atlantic used to be a place where storms would form but now it takes everything being completely perfect to spit out one good storm. Could the salinity of the water from melting ice be to blame? Hurricanes need salty water right? Dumb question I know.

[Darvince]

1) It is July 22. The median Atlantic ACE for this date is 6.8. We have very slightly less ACE than that.

2) Climate change will not make the Atlantic a weaker basin, and ice from the Arctic cannot reach the tropics. Outside of Newfoundland, it melts before reaching 60°N. In wintertime, icebergs from Greenlandic glaciers can sometimes make it into the Gulf Stream, but melt. The only area where these changes will impact salinity are in the far north Atlantic, in an area roughly outlined by Greenland, Iceland, Ireland, and Newfoundland.

3) The fact that the wave is not predicted to develop immediately once it exists the coast of Africa is not a good indicator that the Atlantic as a basin is becoming less active. It is because of dry air, a very typical feature of July in the Atlantic.

[USTropics]

GFS says what storm? LMAO completely caved in to the other models. Phantom storm it seems. The Atlantic used to be a place where storms would form but now it takes everything being completely perfect to spit out one good storm. Could the salinity of the water from melting ice be to blame? Hurricanes need salty water right? Dumb question I know.

No hurricanes do not need salt water, it's mostly water temperatures that propels them. In fact, less salinity in the water could be more beneficial.

Salty water is going to naturally be more dense then fresh water. In areas of the ocean where excess rainfall or river deltas dump into the ocean, we can see a top layer of fresh water, creating more depth to the thermocline. This is referred to as a barrier layer, and it develops when the psynocline (density transition depth) is shallower than the thermocline.

Essentially, a barrier layer forms when the surface water becomes much less dense than the saltier water below, preventing the two from mixing. This means less upwelling (36% less at times).

There has been some extensive research on this as well. In fact, researchers used observations and high resolution climate model simulations to analyse almost 600 tropical cyclones in the major tropical barrier layer regions — the Western Tropical Pacific, Tropical Northwestern Atlantic, and Northern Indian Ocean tropical basins — from 1998 to 2007.

You can find out more in this PNAS article: http://www.pnas.org/content/109/36/14343.short

Below is the Abstract:

Improving a tropical cyclone’s forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone’s path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are “quasi-permanent” features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

Also one other thing. The melting glaciers will have a global impact on ALL oceans, not just the Atlantic.

[Hammy]

3) The fact that the wave is not predicted to develop immediately once it exists the coast of Africa is not a good indicator that the Atlantic as a basin is becoming less active. It is because of dry air, a very typical feature of July in the Atlantic.

I agree but it certainly doesn't say much for how good the upgrade was--the lack of phantom storms over the last several weeks had my hopes up that the model would actually be slightly accurate this year.

I will add regarding some of the reduced forecasts: weather watching is 90% patience and waiting.

Regarding the salinity, I've seen numerous reports after 2013 that climate change could be causing a reduction in the thermohaline circulation by injecting too much fresh water in arctic areas, and this reduction could increase salinity in the tropics--the Atlantic could be more effected due to the largest land glacier in the northern Hemisphere being on Greenland.

On the matter of model runs, the Euro indicates waves are going to start making it into the Gulf of Mexico, and even if it shows no development at the moment this is a major change given they've been pushed straight west into the Pacific on a near constant basis over the last six weeks.

[stormwise]

https://i.imgsafe.org/1de89c52ed.png
Ens same storm as the GFS, but a fish cane.

[Fego]

https://i.imgsafe.org/1de89c52ed.png
Ens same storm as the GFS, but a fish cane.

Good morning. Is that link available? Thanks.

[cycloneye]

 https://twitter.com/MJVentrice/status/756472310455033856

[euro6208]

Weak shallow systems is what models have seen in the Atlantic basin year after year... We see GFS/Euro bomb out EPAC systems on a regular basis... Not sure how many years must pass before it becomes a trend... Rarely do we see a well developed Atl system in the model runs... Likely the Atlantic will hit the number mark, but it sure does seem the storm quality has dropped significantly for near a decade... BOC & N Atl have been the breeding grounds... Just a very amateur observation...

The Atlantic is like the little sister to the EPAC (Father) and the notorious WPAC (Mother). It's just the way it is.

[JaxGator]

Weak shallow systems is what models have seen in the Atlantic basin year after year... We see GFS/Euro bomb out EPAC systems on a regular basis... Not sure how many years must pass before it becomes a trend... Rarely do we see a well developed Atl system in the model runs... Likely the Atlantic will hit the number mark, but it sure does seem the storm quality has dropped significantly for near a decade... BOC & N Atl have been the breeding grounds... Just a very amateur observation...

The Atlantic is like the little sister to the EPAC (Father) and the notorious WPAC (Mother). It's just the way it is.

History tells of all basins having all their unique storms.

[srainhoutx]

Conditions in aiding the development of vigorous tropical waves are slowly increasing across Africa and the Indian Ocean as we near the end of July and begin August. The quiet pattern across the Atlantic Basin appears to be near the end of its 6-7 week slumber as the Eastern Pacific shuts down and potential tropical activity in the Atlantic Basin begins.

[JaxGator]

Newest run from the GFS has a TS in 120 hours/five days. Interesting that the Euro is beginning to sniff out something too.
http://www.tropicaltidbits.com/analysis ... ics_21.png

[chaser1]

Newest run from the GFS has a TS in 120 hours/five days. Interesting that the Euro is beginning to sniff out something too.
http://www.tropicaltidbits.com/analysis ... ics_21.png

I'd say the tide's a turning.....

[cycloneye]

12z ECMWF at 240 hours has a weak circulation close to CV islands.

[JaxGator]

Looks like the wave that will spawn the possible system has formed over Africa. Nice shots of the wave train too.
http://tropic.ssec.wisc.edu/real-time/e ... et7kml.GIF
http://tropic.ssec.wisc.edu/real-time/e ... /irnm7.GIF

[tarheelprogrammer]

Looks like the wave that will spawn the possible system has formed over Africa. Nice shots of the wave train too.
http://tropic.ssec.wisc.edu/real-time/e ... et7kml.GIF
http://tropic.ssec.wisc.edu/real-time/e ... /irnm7.GIF

Very nice looking wave but all that dry air out there will make it look terrible in a few days. Still a huge wave with plenty of moisture.

[Hammy]

GFS seems to develop something and then turn into a gyre almost suddenly, so I'm wondering if the model has been having feedback issues the last few runs. I remember something similar happening with Danny last year and Andrea in 2013 as well.

[tarheelprogrammer]

GFS has not only caved to the ECMWF but it has completely dropped a storm pretty much. There is always a chance the system/wave organizes quite well and defies the models like Joaquin did last season. However, every time the models hint at a pattern change or something brewing they seem to back off from it. Just an observation.

By the way if the models are correct and nothing forms up to the beginning of August then it will be the longest length of time during a season without a storm forming since 2009 and I could be wrong but it appears to be the last season to go this long a named storm or TD. I am talking solely about length of time without a storm I do know we have had named storms already this season early on.

https://en.wikipedia.org/wiki/2009_Atla ... ane_season