Stubborn ridge to continue … for awhile … NWS

.LONG TERM...(Monday night through Saturday)
Issued at 225 AM MST Sun Dec 10 2017

The ridge out west will hang on through most of the upcoming week.
There will be a compact clipper type system survive a trip over
the top of the ridge and dive into the High Plains on Wednesday.
Cooler air arrives aloft in the wake of this system and it may
weaken the inversions just a tad but models have not been handling
this feature very well the past few days. A more significant
Pacific wave crashes into the ridge going into Friday.
Unfortunately there is no consistency with this feature this
morning. The best hope is the Euro which weakens but keeps this
wave intact as it swings across the Rockies Friday night. The GFS
splits the energy dropping a low down to the Baja while swinging
the northern split across the Dakotas. This second pattern is more
familiar lately so will probably need most of the week to sort
this out. Otherwise plan in dry conditions continuing.

GFS – US – 500mb – Loop