http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
Full disk satellite imagery shows tropical convective forcing literally breaking up into tropical cyclones from the Bay of Bengal into the
The first point to make is that MJO variability is currently strongly impacting
Official forecasts have not yet picked up on this (at the time of this writing), being fooled by model disagreement, etc.. This again demonstrates the need of an atmospheric dynamics based weather-climate linkage framework to intelligently evaluate numerical model guidance (insert my angry Rottweiler)! One purpose of the WB (2007, 08) GWO is to facilitate the latter. There is no cookbook to making subseasonal forecasts, and that includes blending numerical model predictions!!! Ensemble prediction schemes such as from ESRL/PSD as well as the deterministic ECMWF model have provided the most realistic solutions for the
The final point is that a potentially explosive pattern for severe local storms on the Plains exists for at least week-2 (exact timing is white noise). Locations to get hit the hardest may be farther north than observed during the last few weeks (climatology understood). The latter may extend from portions of
Locations from portions of the Bay of Bengal into Indonesia/Southeast Asia and the Philippines are still likely to get hammered with intense to severe thunderstorm activity week-1 including tropical cyclones (please see JTWC). This activity is probable to weaken weeks 2-3 as tropical thunderstorm activity increases from Africa into the
The best shot for enhanced Western Hemisphere convection, impacting northern South America into the Atlantic ITCZ appears to be weeks 1-2. I trust the expertise of the appropriate weather centers internationally to alert the public of additional weather hazards worldwide.
An experimental quasi-phase space plot of the GSDM utilizing time series of normalized global relative AAM time tendency (Y-axis) and normalized global relative AAM anomaly (X-axis) can be found at
This phase plot is being re-done, as is the web site. Stay tuned. We call the behavior of this plot the Global Wind Oscillation (GWO). While the intent of the legacy GSDM is to extend current thinking beyond the MJO, the GWO quantifies variations used to derive the original GSDM in a manner that is “user friendly” analogous to the WH (2004) “convention”. In addition, the GWO plot does not have the ENSO signal removed.
Please see the revised description of the GSDM per above link. Also, I encourage the readers to study the annotated MJO and GWO phase space plots to help relate the global variations explained by those techniques to “weather”.
Links to CPC and PSD ENSO discussions:
The following is a link to information about the stratosphere and other nice monitoring tools:
These are probabilistic statements, and work is ongoing to quantify in future posts (for example, risk assessment maps, signal to noise ratio plots and shifts of probability). We hope that an opportunity will arise for us (soon) to have a dedicated web page effort to expedite more objectively, with rigor, thoroughness and verification.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. In addition, a two-part paper is in ACTIVE preparation by WB that will formally introduce the GWO along with subseasonal composites for variables such as surface temperatures. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships.
Given shift work and travel, updates are extremely difficult. I should be able to post another discussion the weekend of 24-25 May.