IOP on track?
The weather disturbance talked about Monday and yesterday for next week continues to provide an opportunity for an IOP. Tropical convection has been reorganizing over the past few days as a weak dynamical signal from the recent MJO moves through the western hemisphere and convection increases again over Indonesia and the west Pacific. The increase is being aided by warm SSTs centered around 160E and favorable upper level wind anomalies. The possibility exists that the mid-latitude distrubance next week or the one following will interact with this convection and help produce an extension of the Pacific jet stream and drive disturbances into the west coast.
Subtropical westerly winds are relatively weak although we expect some strengthening near 25N as the opportunity for an IOP approaches. Overall the pattern still favors ridges over the east-central Pacific with downstream troughs over the western North America. This pattern may re-exert itself after week 2 if convection shifts westward or a new MJO develops over the Indian Ocean. In the meanwhile we feel the ECMWF ensemble and deterministic GFS and ECMWF provide the best guidance for the next week.
For additional discussion please see
Klaus Weickmann and Ed Berry
NOAA/ESRL/PSD and NOAA/NWS