Quiet Pattern Shifts To Slightly Active

For the last three weeks, thanks to a dampening MJO pattern and "Sudden Stratospheric Warming Event", the West has for the most part been situated under either amplified ridging or dry troughing.

The MJO (past and forecasted above) is now entering a somewhat amplified Phase 7.  For the last 3-4 weeks we went from no MJO to the very dry Phase 5 and 6 and now into Phase 7.

Take a look at the anomalies above for all 8 phases of the MJO.  Though not a soaking Phase, Phase 7 is a wetter pattern than the very dry phase 6-7, historically.

Something interesting that has been ingested in the models in the last 48 hours, is Air Force Flight Recon. data.  Flights went out in the Pacific to sample the southern stream of the jet stream.

From HPC......

ENOUGH SUPPORT/EVIDENCE DURING THE LAST 48
HOURS TO REQUEST A SERIES OF NOAA G4 WINTER RECON FLIGHTS TO
SAMPLE THE NORTH CENTRAL PACIFIC BETWEEN HAWAII AND ALASKA.

This extra and more accurate data has changed model output drastically for both Wednesday's system and this coming Weekend's system.

Though not strikingly wet, Wednesday's system is now trending much wetter than a nearly dry system seen just 36 hours ago.

The image above is the Euro forecast model's output for Saturday's system.  You can see a positively tilted trough about to slam in to Northern California.  This should supply at least enough energy for scattered showers and storms, if not some sort frontal precipitation shield.  Something to watch the next 5 days.