During the summer months when forecasting US weather, one must watch what’s going on the other side of the Pacific and when there’s typhoons, we pay particular attention.

The Pacific has indeed been very active this year, largely down to the strong El Nino and warm PDO. The development of typhoons is one thing but where they go is another and it’s the track which can have significant downwind influence on the US pattern.

Typically a westward tracking system into China means there’s a greater chance of ridging over the Midwest and Eastern US where as a recurve over or east of Japan and remaining over the Pacific as it tracks northwards, typically supports a trough over the Midwest and East 6-10 days later.

Before we get to the hotter end of the month, the upcoming 5 days looks downright chilly down the Plains with not 1 but 2 fronts coming down.

The GFS 5-day mean 500mb height anomalies show the initial cool punch followed by warmer times.

The GFS suggests some chilly mornings in the comings days of the central US.

We have plenty of action in the west Pacific over the next 10 days. How much can we take from this?

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Joint Typhoon Warning Center tracks.

The issue I have is that both major typhoons (Goni & Atsani) have a recurve look according to the models but the GFS supports major ridging between Aug 25-30 but the more recent runs do hold the ridge further west over the Mississippi Valley which would make for troughiness over the Northeast potentially.

Initially, the ridge expands west-east from California over to Texas and as we progress through the final week of the month, the 594dm ridge expands north over the Plains and into the Midwest, Great Lakes. Earlier runs took the 594 height line into the Northeast but the newer runs hold it west which coincides with RECURVING typhoons.

How hot may it get? A 594dm high could support 100 degrees for cities such as Los Angeles, Des Moines, St Louis, Chicago.

The 2-3 systems developing over the western Pacific will be closely monitored here as their track will be crucial to the final 10 days of August over the US. The ECMWF also pumps the ridge but is slightly less aggressive.

Here’s a look at what the GFS is suggesting towards the end of the month.

Slightly different but the ECMWF too is hinting at a hot end to August but centred more over the Plains.

Will have a video for you tomorrow.

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