Pattern change underway with first system to bring light to moderate amounts to the high country tonight…..then major storm for the weekend into next week!

 After a small storm tonight…… (3 to 6 inches in the village) and 6 to 12 inches over the crest….

The long awaited shift from dry weather to wet will arrive Friday as a strong upper jet coming off Asia will have the effect of displacing the dateline upper ridge far enough east to get the central west coast and California wet again. The big emphasizes is on the REX configuration of the central pacific upper ridge where the upper low south of the ridge will provide for some pretty rich juice to be entrained into the west coast trof, beginning Friday night into Sunday.  Looking at the precipitate water loop, there are some PWA areas west of Hawaii up to  1.75 out there that will head for the central west coast this weekend. High moisture flux and upslope conditions along the frontal boundary should support heavy snow from the Central Sierra north.  HPC QPF has 5+ inches for the crest by Sunday. It should also be noted that 1000mb/500mb thicknesses are between 558dm and 564dm. So this will be definitely be Sierra Cement over the upper elevations this weekend and could possibly be rain at times in the town of Mammoth. The Dweebs will fine tune snow levels later this week. The models keep changing on the idea on the amount of rain we will have in town.  A good look at the Oakland sounding Friday afternoon  should help. Hopefully,  Cylke’s micro-physical processes will come to the rescue!

Outlook:


Next week continues to be wet with snow over the upper elevations…..The Dweebs will have to keep a weary eye on the subtropical ridge over the Rockies to see when everything shifts back to the north. Will it be Mid week or as late as Christmas?


Dr Howard and the Dweebs…………………..:-)




——————————————————————————–
Reference Glossary of Weather Terms

First system in the series to move through Mammoth Tuesday/Night….Followed by wet snowy weekend

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!

Upcoming systems….

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

Fab Weekend Followed By Fab Snowfall Later In The Week

OK……Here we go…..

First of all…This is not just any La Nina Winter….This is La Nina on Steroids…..Check this out for 12-10-2010.  http://weather.unisys.com/surface/sst_anom.html  Look at the  nose of the western extension of the cold/negative SSTAs all the way to 150E!  And….what the heck is this? Another extension of La Nina off South America from 70w/25S feeding into the main cold stream to 150w?   Also Solar Cycle 24 is an incipient maladroit. Will it get going before it is over…..Solar Global Cooling?

FLASH!  The warm wet pattern of Wednesday through Friday is over. A highly amplified upper ridge has taken over and we’ll have fabulous weather through Sunday!  The 500ht 588dm height line gets very close to Bishop Sunday AM. Still going with a 70 for Bishop Sunday. These temps are 15 to 20 degrees above normal.

Now on to next week.  First of all….Yes, it is going to snow. The question is always, how much.  The short answer is a lot. However, it may take a good part of next week and into the following week to get the fuse lit. 

Some considerations…

I like what MJO is doing…  It is well into the Phase 5 and still building in strength contrary to some dynamic models. It should move into Phase 6 soon. Hope she holds together Scotti! I am attributing at  least some support of the change in the pattern next week to MJO.

Here are the ponderings:

The ECMWF and Canadian are both very wet later in the week and especially next week.  The GFS is not. The Dweebs feel that the Europien  would be the superior model to the GFS,  in handling QPF in the upcoming flow pattern for the west coast next week and into the next. So, the rational is the GFS is too dry and gets rid of the pattern too fast…in stead of developing it further.

The other supporting evidence is MJO. The Dweebs feel that next week beyond the 19th is going to be particularly wet.  However, there is the potential for rising snow levels as well! So it could get messy for a spell. I think that we will  have to be concerned about the building of the subtropical ridge at this latitude later next week; (Week-2).


The first system for Tuesday night/Wednesday does not look major. (QPF .5 to .75)

The Dweebs will fine tune snow levels later.

Bigger storm later in the week…………………Stay tuned…………:-)


Dr Howard and the Dweebs………………………….:-)

——————————————————————————–
Reference Glossary of Weather Terms