Thread by @althecat

#ClimateChangeNow THREAD

Hurricane #Estelle has spun up & grown into a massive 800k wide storm.

Whilst #Estelle is expected to remain over open water its impact on the Tropical Mega-Atmospheric river mean it's impacts will be felt in East Asia 13k kms away.

I discussed this in my thread 13 days ago which takes a deep dive into the relationship between a more extreme tropical rain belt and #extremeweather globally.

#Estelle is stronger than models had expected four days ago ,and is currently forecast to become a major hurricane tomorrow.

Like Hurricane Darby (which remains active) take a fairly straight trajectory keeping it away from coastal North America.

#Estelle's genesis was remarkable shown here transitioning from a drepression into a storm on Friday.

And 12 hours later #Estelle became a Hurricane.

#Estelle is forecast to become a Category 2 Hurricane in the next 12 hours and a Major Hurricane within 24 hours and to remain at Major Hurricane strength for 48 hours after that.

#Estelle is also huge in size with intense convective bands extending 400kms from her center already, even though no eye has yet formed. She is - in summary - an extraordinary convection engine, delivering vast amounts of water vapour into the upper atmosphere.

In my thread back on Wednesday I looked at what the impact of all the additional water #Estelle is now generating would have in East Asia. The image below is an update of the GFS3 atmospheric water forecast from the quoted tweet below.

With more water than originally expected flowing into the system, the expected outcome is significantly worse.
Left. Forecast of a super typhoon hitting Shanghai Aug. 2nd
Right. Forecast (13/7) of relatively minor storm arriving 25/7.

Here are the two model forecasts two days apart. The latest forecast shows a massive slow moving storm similar to #Infa which struct China last July.

WARNING NOTE: The Chinese Storm forecast in the GFS3 Model run above is 16 days away and these forecast models are not accurate at this range.

That said, due to the forecast significant build up in atmospheric water in the Western Pacific #extremeweather is certainly possible.

The purpose of the thread from the 13th was to take a look at the cascading effects of water flow at the tropics in relation to possible #extremeweather events a year on from the catastrophic floods in Europe and China in 2021.

The effects of atmospheric water in the tropics have cascading impacts as water flows Westward. Here we see an updated Indian PWAT model taking into account #Estelle. (and the 13/7 comparison)

Here are comparative 16 day rainfall forecasts for 13/7 and 17/7 for the North Indian Ocean Region.

Here are comparative 16 day rainfall forecasts for 13/7 and 17/7 for China.

There remains a massive level of uncertainty about all of this however, with a lot resting on what happens to #Estelle's development and track.