A Look At the Far Northwest Pacific

The GFS and ECMWF model forecasts are still producing fairly different solutions for the 500 mb S/W trough or cutoff that comes into the west U.S. at the start of next week. Perhaps this uncertainty is due to the degree of downstream response in the forecasts to the intense cyclogenesis predicted to occur in the northwest Pacific and Bering Sea. The images above are the 48-hour forecasts (for the 00 UTC runs last evening) from the GFS operational member for the surface (top) and 500 mb (bottom). The very strong surface low in the Bering Sea appears to have a forecast central pressure of around 964 mb. The downstream response, ahead of the strong ridging that occurs across western Alaska, produces a significant vorticity streamer that feeds into the rather benign S/W off the northwest coast of the U.S. This flow also brings along an infusion of very cold air at middle levels. The result is a significant intensification of the eastern Pacific S/W after 48 hours. Currently the ECMWF brings this system ashore further south and with greater intensity than does the GFS. The model that best predicts the events off in the far northwest Pacific will probably also verify best over the western U.S. Something to watch the next couple of days.