Look, the west coast has been under a regional anomaly ridge. Whether that is the warm SST pool, or some other factor, the reality is that the weather has been defined by the position of that ridge. As can be noted now for two years, when north central CO started going off in Feb if 2013, the eastern movement and western retrograding of that ridge has defined our seasons.
Right now, the forecast is for retrograding the ridge into the eastern pacific - this is what has opened by the storm cycle here as northern CO up into the northern Rockies continues to benefit. Look at this from today:
Originally Posted by NOAA southern CO
SECOND...MORE SIGNIFICANT SYSTEM ARRIVES MID-DAY ON MONDAY. THERE
HAS BEEN GOOD RUN-TO-RUN CONSISTENCY WITH THIS SYSTEM. H7 TEMPS
SHOULD FALL TO MINUS 8 TO MINUS 12 BY 00Z TUE BEHIND A STRONG COLD
FRONT. MOST OF THE PRECIP SHOULD FOLLOW THE FRONTAL PASSAGE. GRIDS
CURRENTLY HAVE A BRIEF PERIOD OF RAIN CHANCES ON MONDAY BEFORE TURNING
TO ALL SNOW MON EVE...HOWEVER THIS IS MAINLY DUE TO TIMING
UNCERTAINTIES WITH THE FRONT. EXPECT THIS TO BE A MOST OR ALL SNOW
EVENT AS TEMPS BEHIND THE FRONT FALL QUICKLY. THE EC HAS H7 TEMPS
FALLING TO MINUS 21 OVER THE I-25 CORRIDOR BY 12Z TUE...AND THIS
WOULD BE SOME OF THE COLDEST AIR WE HAVE SEEN THIS WINTER.THE GFS
IS ONLY SLIGHTLY WARMER AT MINUS 18 DEGREES FOR H7. BOTH MODELS
CONTINUE TO PROG BETWEEN THREE QUARTERS TO OVER AN INCH OF QPF FOR
THE ERN RANGES AND ADJACENT PLAINS. SO THE POTENTIAL IS STILL
THERE FOR OVER A FOOT OF SNOW OVER THE MTS...AND SIX INCHES OR
MORE FOR PORTIONS OF THE PLAINS. STILL A FEW DAYS AWAY...BUT WILL
HAVE TO WATCH THIS SYSTEM CLOSELY OVER THE NEXT FEW DAYS.
The NW flow is there with the ridge backing off - that forecast focuses on the urban corridor, but the storm projection is slow movement from NW to SE CO....favorable positioning for a strong storm to run right down the east side of the ridge. With potentially very cold temps. That kind of energy is exactly what we expect as the climatological Spring approaches....and why March and April are our stastically biggest months.
Now this is days out so we will see, but these patterns have consistently delivered this season because they haven't been moisture starved. Quite the opposite, and now the highest energy part of the season is upon us to create storm dynamics...something that is always lacking in the coldest and driest part of mid-winter (except warm this year for some great skiing).
The interesting question for us folk on the favorable edge of the ridge is whether this warm season is going to generate some big spring dynamics. It's been quiet relatively these past few Spring seasons with a weak cool ENSO. You ask me, eastern CO is due to go off, favoring that continental divide microclimate and the eastern resorts as the season progresses. But then wishful thinking matters not