Active weather has developed across the interior West, with severe thunderstorms in E. OR, N. ID, and W. MT. Activity will diminish after today, but will persist at a diminsihed level in many areas. Major fires in NV, ID, MT, and WY will be fanned by strong winds, dry air, and possibly dry thunderstorms for the next few days, though today will be the worst day. AZ and NM continue to see heavy rain from thunderstorms, and this is expected to continue. Tropical Storm Hector is rapidly gaining strength in the Eastern Pacific, and is expected to become a hurricane shortly. The storm is forecast to take a NW track, trending more N with time. The storm will slowly weaken once it reaches cooler waters, but a remnant circulation along with significant convection will remain even after the system drops below T.S. strength. The NAM (now the WRF) has been adamant about developing a cutoff low SW of CA in the next 48 hours. It indicates that copious moisture from Hector will be caught up in the southerly flow ahead of the low, bringing potentially significant convective activity to CA by the weekend. The GFS, equally consistent in its output, does not develop nearly as deep a low and develops the low much further east, not bringing any moisture into CA from the south. This major discrepancy will have to be resolved soon as the potential event is only 4-6 days away.
In the longer term, the GFS does indicate a return to a Sonoran ridge-dominated pattern. This means a continued moonsoon flow in the far SW, warm to hot temperatures across the entire West, and the potential for monsoonal surges to make it further west than they have in the past month. Also worth noting is the GFS forecast of several strong tropical systems in the Eastern Pacific during the next 2 weeks. Flow will be at least somewhat favorable for remnant moisture from these systems to be advected into the SW throughout the period. Stay tuned.