By Paul Huntington
Time to bundle up everyone because Thursday Jan 5 will be down right freezing with mostly clear skies, a few passing clouds and very LOW temperatures in the teens as Arctic air plunges down from Alaska. It should be one of the best ski days in a while for higher resorts that have a larger base. This appears to be some of the coldest temperatures in a while, possibly since December 1998 when I recorded snow along the beaches of Central California! Now that we have a solid frozen base this is a very good pattern for a sustained season and water storage as the fresh snow accumulates on the established base that almost melted during the last warm atmospheric river storm but has now refrozen into a thick slab of ice (lower elevation resorts like Bear Valley, Sierra Summit, even Sugar Bowl did not fair well with the warm storm though and be very careful about hidden rocks under fresh light snow!!).
Friday 1/6 and Saturday 1/7 appear to be clear and cold with temperatures moderating a bit from the coldest day on Thursday. These should be epic ski days!
Things began to look extremely exciting heading into next weekend 1/7-1/8 and it looks like we are in store for a very active wet snowy pattern! The omega block transitions into a strong rex block (high and low form a closed circular low not enabling energy to spill over the top of ridge) and is instead undercut by a steady stream of lows moving into the East pacific but at a lower latitude allowing them to undercut the rex block and make a stampede toward the West Central Coast. These storms will be more mild and wetter than the Tuesday- Wednesday storm this week and could bring very copious amounts of the decent snow to the Sierras. I would predict more strong storms to follow into the 1/9-1/12 period and possibly longer. Moreover the Madden Joulian is still displaying a rather weak signal but if and when it acts up (possibly around mid January) it should propagate east from the Maritime Indonesia/Papua New Guinea area into the Pacific. If these teleconnections come together meaning the rex block being undercut, MJO wakes up (should with La Nina dissipating quickly now), negative phase for both Arctic Oscillation and North Atlantic Oscillation it would spell FLOODING for California and massive amounts of snow that could literally bury Tahoe. I want to say I have been waiting almost 20 years for this sequence and it could be its time?
Notice how the AO and NAO are following each other very close now. This signifies the polar vortex splitting, displacing the polar high and causing more sinuosity in the Northern Hemispheric Planetary/ Rossby waves and drives the jet stream under the Rex Block, similar to what triggered the bought of rain last January. I am also thinking February continues to be active unlike the last few years??
Cheers to active patterns!