A window of opportunity next weekend?
Posted by JAC on 7/31/2009, 10:29 am
So, I think the last high-amp African Wave was a direct victim of El-Nino.

Yesterday morning it had a consolidating LL vorticity.

But, it also had an UL air-circulation pattern over it suggesting UL subsidence; i.e. sinking air coming from the tropopause.

The fact that the LL vorticity was suddenly killed and coincided with an increase in the UL flow pattern over it; to me, suggests that an Atlantic Walker cell has been set up.




The updraft of the Walker cell is coming from the UL High currently over north Mexico into Baja and out into the EPAC.

The first plot below shows current UL heights with the ULH outlined by the 1104 isobar.

UL winds are then carried east and sink toward the surface around 35W; i.e. in the east Atlantic.

So, the thing to watch for is what is happening to the ULH over Mexico and the EPAC.

From the 1st graph, two things are visible.

1) A strong, ULL anchored off CA coast
2) The ULH over MX/EPAC.

These two are inter-related.

Next weekend the CA-coast ULL is forecast to move NE into the CONUS and weaken the associated ULH which is driving the Atlantic Walker cell.

That is shown in the second graph below.

This in turn could weaken the associated subsidence area in the east Atlantic.

Also of note, is that the Bermuda High will be pushing NE by next weekend; possibly reducing MSLPs in the west Atlantic.

And it looks like a very moderate TUTT will be setup then at 30N 60W.











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A window of opportunity next weekend? - JAC, 7/31/2009, 10:29 am
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