Friday, May 25, 2007


Reanalysis-1 (R1) data woes still continue meaning ESRL/PSD AAM plots have not updated since May 11th (as well as the GWO phase space plot). Work on resolving this problem is occurring as I type.

I will not post a discussion today since I had to cover an operational shift. I do plan on issuing a discussion on Monday, 5/28.

However, I did have time to do some monitoring, and there is little change from my thoughts given in the May 22nd Blog discussion. The tropical convective dynamical signal is centered ~0/60W and there is now a zonal wave number 1 spatial pattern to the 200mb velocity potential field. Tropical convective forcing is increasing across the Indian Ocean just south of the equator. By the end of week 2 the dynamical signal should be well into the Eastern Hemisphere supporting strong convection from the warm Indian Ocean perhaps into the Indo-China region (including onset of the Indian Monsoon). Suppression may be prevalent across the west central Pacific. In fact, there may be some truth to what the Wheeler phase space plot is already depicting. A true MJO may be developing, or at least a spatially coherent region of tropical forcing and circulation response.

I think the global weather-climate state is solidly in GSDM Stage 4 given increasing easterly flow across the upper tropospheric tropical/subtropical atmospheres and relative AAM becoming negative (per operational plot). Tied to what may be a negative East Asian mountain torque, a baroclinic wave packet coming off that continent is interacting with a downstream Rossby wave train. A probable solution is a slower and deeper western USA trough early next week and some models are beginning to capture that. During week 2, the strong North Pacific jet shown by most models is likely to be transient as the tropical forcing intensifies across the Eastern Hemisphere. I favor an evolution toward GSDM Stage 1 increasing the probability of yet another unseasonably strong western USA trough by week 3.


An experimental phase space plot of the GSDM utilizing normalized relative AAM tendency (Y-axis) and normalized relative AAM (X-axis) can be found at

These are probabilistic statements, and work is ongoing to quantify in future posts. The WB (2007) paper on the GSDM has been published in the February issue of MWR. I plan on writing a posting 5/28. Also, since I have to cover additional shifts next week, the posting after that is likely to be the following Monday, 6/4.

Ed Berry

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