Current Strato-Warming “In Process”and the flip of the QBO to Easterly Suggests That Arctic Air Will Decend Upon NA..
Saturday January 7, 2012
Posted at 9:25 am by Howard
Quick Update Saturday 1:15pm
*Today’s Operational 12z Run of the ECMWF and the EC ensembles have the ridge ridge axis at about 166 west. This is much more encouraging then last nights 00Z run of the GFS. the Differences is a location of about 240 miles further east which results in the heights being about 50 to 60 meters lower for the Mammoth area. That would likely mean a lower snow level.
Checking in on the current state of the well advertised strato-warming event…..the data via (EC Ensembles 360hr) at the 10mb level is pretty amazing showing the warming over the N pole going from -68c to -18c at 10mb over the current 15 day period. (360hours). Check out the GFS over the upcoming 240 hours period. http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/
Additionally, the QBO’s easterly flow continues to deepen in elevation and is now over much of the hemisphere near the equator in which relevance supports strato-warming and the GFS upcoming AO flip in the next (6 to 10 days) The GFS is forecasting the AO to be in negative territory by the 15th of January. Remember, that there is a correlation to a positive AO and dry weather in California.
This all adds up to a forecast that Arctic Air, via Siberia and Alaska should invade North America the second half of this month. The exact timing is uncertain but best guess is about the 3rd week of January.
*The key to what Mammoths weather will be like always revolves around where the pacific ridge set up. Set it up too far west and we ridge up. Too far east and we ridge up. Too far north near AK, you get under cutting of the westerlies. If it is too far west and north we may get rain as the wave train comes up from the lower latts (Subtropics). The GFS 00z 7th sets up the mean ridge over the Bering Sea at 170 west. It closes off an anticyclone at 500mb with 300 meters of the southern branch (wet) by the afternoon of the 17th. http://www.hpc.ncep.noaa.gov/cpc/cpc_NAM_f264wbg.gif
That is a relatively warm wet pattern for the Central Sierra as the mean heights over Mammoth would be in the mid to upper 560sdm. The 564 line at 500mb cuts across Tahoe. Snow levels in saturated air 8.5K to 9.5K? depending upon micro physical processes/sounding. Again the key will be where the upper ridge sets up. The Dweebs would like to see it closer to 160west so we get more energizing from the polar jet and a cooler air-mass. (confluence)
The good thing is that the pieces to the puzzle are coming together and although we have another good week before we can nail it down, the light continues to grow brighter that a change to a wet pattern is nearing and the end to a very long dry spell……
Latest Climate Model anomalies show it going dry again week 4.
Dr Howard and the Dweebs…………………………..:-)
Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.