First system in the series to move through Mammoth Tuesday/Night….Followed by wet snowy weekend
Monday December 13, 2010
Posted at 9:24 am by Howard
The long wave pattern will change over the next week…however one resounding fact remains…..the snow level will be higher then normal for the month of December. Why?? The long wave trof is too far west along with the long wave positive height anomaly near the dateline. Until these features shift east….we will most likely be more effected by the subtropical jet then the polar jet. The best that we can hope for is the right rear entry region of the polar jet. The MJO seems stuck in Phase 5. The Dweebs are looking forward to the new CPC weekly discussion today to shed light on the matter. If the MJO would continue to track eastward and remain as strong as it currently is, that would have a profound effect in dislodging the current ridge/trof positions. That most unlikely will not happen because of La Nina and how far west the Negative SSTA’s are. The MJO will probably die or at least significantly weaken over the graveyard of the warm waters of the Maritime continent.
Monday Am update:
The new 12z Monday GFS does show a strong Asian Jet having the effect of temporarily shifting the long wave features east some 1000mi. That is how they accomplish all the precip between Friday and the following Wednesday. This is just a temporary eastward shift as the pattern retrogrades back again some 1000 to 1500mi before Christmas. Using the operational 12z GFS run this AM, we ridge up again after mid week next week….possibly through the end of the year!
1. The snow level will be about 8000 during the day Tuesday then 7000 feet Tuesday night… with it lowing to near 6500 after midnight. Mammoth Mountain should get 6 to 12 inches….with the village….4 to 8 inches. This will be mainly a Tuesday night snow event for the town…… highs in the upper 30s Tuesday at the village.
2. A split in the upper flow will give a bit of a break Thursday. Snow showers still possible but the main short wave is coming in split.
3. The new 12z GFS is now very wet for the weekend beginning Friday and continues though Monday am. Several feet of snow is expected over the Sierra this weekend. 1st guesstimates, 4 to 5 feet over the crest. (This may be bumped up later) There appears from this model run…. plenty of snowfall for the plows in town as well.
The new guidance is colder now with the upper jet a bit further south. So….. A pretty much non stop dump (with some breaks) is portrayed beginning later Friday through Sunday night. The upper flow continues natural to Sierra through Tuesday night with excellent orographics. The grand fennalli comes in Tuesday/night associated with a 996mb surface low W of the Bay area. That is being portrayed by the new Monday12z GFS as the grand daddy storm that will really dump in a short period of time. There after, if the longest guidance is correct…..we should gradually ridge up, as the long wave features retrograde west. Christmas looks fair at this time……
Dr Howard and the Dweebs……………………..:-)
Reference Glossary of Weather Terms