“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
The 91-day signal to noise ratio (snr) anomaly composites are now updated daily, centered on the date shown (see product descriptions). On-going map room issues causing missing data and unrepresentative plots are getting resolved.
There is little change in the global tropical SSTs from a week ago. Perhaps most notable is the warming of the equatorial and South
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
Decoupling of signals defined by the WH (2004) measure of the MJO and WB (2008) measure of the GWO has occurred. Interactions between tropical convective forcing shifting into the TNWP, extratropical processes involving the eddies and global mountains have removed subtropical easterly wind flow anomalies. Through 18 September global relative AAM was near the R1 data climatology.
A recent strong positive global mountain torque event, ~20 Hadleys largely from the Andes, has forced the WB (2008) GWO signal to propagate rapidly through the
Meanwhile, the weakening WH (2004) MJO signal was in octants 5-6 of phase space (~1 sigma projection). However, leaving the interannual component in, the projection was much weaker and drifting toward Phase 3. Hence phase 3 of the MJO 250mb psi and 2m air temperature composites may best represent current tropical circulation and North American 2m air temperature anomalies, respectively.
During the next several weeks (exact timing is noise), the WB (2008) GWO should continue ~10-20 day orbits in phase space, from octants 8-1 to 4-5. I expect the GWO signal mentioned above, already coming back into the Eastern Hemisphere, to contribute to a rapid increase of equatorial
Tropical cyclone risks will continue from the TNWP into the
Please see the latest official tropical cyclone forecasts for all basins. I trust the expertise of the appropriate meteorological centers to alert the public of additional weather hazards worldwide (high impact weather events are still continuing).
Links to CPC and PSD ENSO discussions:
The following is a link to information about the stratosphere and other nice monitoring tools:
The following is a link to NCEP model verifications (surf around for lots more).
The following is a link discussing recent global weather and related events.
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. In addition, the first of a two-part paper, where WB formally introduce the GWO (WB (2008)), has been accepted for publication in MWR. The authors are in the process of resubmitting after a minor revision. A pdf version (before revision) can be downloaded from the following link:
Overlapping seasonally varying subseasonal composites for variables such as surface temperature, precipitation, geopotential height and streamfunction anomalies are planned on being posted on the web site mentioned above and presented in part-2 of our paper. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook! I should be able to do a complete discussion next weekend, ~27-28 September.