Thread by @althecat

#ExtremeWeather Update.

There is a lot going on in the Tropical & North Atlantic over the coming fortnight in this latest GFS run. Including two hurricane's and the continuing impact of the remnants of #HurricaneIAN in NE Nth America.

Here's the PWAT version. For Texas's sake it would be best if #Invest91L does not become a TS/Hurricane.

But there are a few other features in that forecast which are alarming. In the short term the MLSP shows the remnants of #HurricaneIAN remaining stationary just off the coast of Maryland for the next 48 hours. Which means this storm is not going away for two days.

Take the low that forms (top right corner) over Newfoundland, Indicating the presence of moisture. looking a bit closer what you find is moisture flooding in from Hurricane Orlene and off the Pacific. And the result is... an arctic blast.

And wild northern Canada/Arctic & South Eastern US temperature anomalies = colisions between warm wet and freezing arctic air.

Here's a snow depth plot for Canada during the period of the Eastern Canada - NewFoundland low presure system.

And a PWAT forecast during the same period.

Producing several rain+snow storms over Canada heralding perhaps the beginning of the ice rain season.

On the other side of the Atlantic the presence of the warm tropical water flows are also obvious. No lasting snow and lots of rain.

Here's a current 24 hour satellite sequence.