12z Saturday GFS Model coming in a bit dryer this morning…..

Just a quick update this morning to indicate that the 12z run of one of the models was a bit dryer than yesterday. However the WRF is still pretty bullish for about an inch of QPF. CRFC has about 1.25 just west of the crest. In that this storm is warmer/wetter then several in the recent past, with Snow to Water Ratios equal to or less than 10:1 ….. considering the topography, 12 to 15 inches is probably the most that we will see up upon Ol’ Woolly!

The majority of all this will occur Sunday night through mid Morning Monday…..The snow level begins about 8000 feet Sunday am, lowering to 5500 by 12z Monday morning.

Longer Range:

Of note…the furthest reaches of the fantasy charts or the second half of week 2 has been fairly consistent in sagging the upper jet south over Central Ca. again. The wavelength does open up across the Conus and out over the Western Atlantic by then. The block over the Aleutians does break down during week 2. 

Another important feature to watch which may be supportive, is that another MJO may be developing toward mid-month. (See)  http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml 

Then check with http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf   for the weekly discussion, early next week to get an update on a possible MJO flair-up. MJO can modulate the westerlies and is usually a pattern changer.

The Dweeber……………………..:-)

Reference Glossary of Weather Terms

Unsettled weather to continue with a good shot of fresh snow Sunday night into Monday AM….upper elevations (9000+)could receive between 15 and 20 inches

Over the next 5 days…..

Northern hemispheric pattern is highlighted by two major blocks. One near Greenland that is progressive. This assisted in a major cold wave over parts of Europe the past several days with fridged air and sever cold over Poland and other nearby areas. This Block is progressive.

The other developing Block in the mean (day +5) is located near the Western Aleutians with a corresponding long wave trof redeveloping in the Gulf of AK at about 140West. The amplifying upstream ridge will once again import cold arctic air from Eastern Asia via the Bering Sea, and fill the trof with it. As the Trof continues to reload with short waves…..This may eventually set the stage for a major wet storm through the Pacific Northwest by about the middle of next week (9th) as cold arctic air phases with southern stream energy WNW of Kauai. The further north you go, the wetter it will be. As of this time….The southern and south central west coast should be protected by upper ridging. 

In the meantime, our weather is still effected by a pattern that is not as amplified with an upper trof that will get kicked in Sunday night. The weekend weather will be unsettled with little snowfall for the high country until Sunday and into Monday with the trofs passage. Snow levels will range from 6500 to 8000 feet. Mammoth Mountain may get up to 15 to 24 inches in the Sunday through Monday period with the town much less. According to the new 12z WRF, prime time will be 06z Monday through 12Z Monday. Expect periods of gusty winds most of the weekend with highs in the 40s then 30s Sunday and Monday. Lows will return to the teens by Monday AM.

Longer Range:   There was some suggestion this morning by the opperational GFS…..that the upper jet would move south again into Central California by about the 15th or 16th of December for a stormy period for the Central Sierra. The change in patter is suggested by a progression of the long wave ridge to 160W…..There is also some support for that progression in the MJO week 2 model.

Reference Glossary of Weather Terms

Weather to remain unsetteled through the weekend…..”Wind Advisories” Hoisted for today

Winds will be on the increase today Thursday as a splitting trof approached the west coast.  A few showers are possible over Mono County. However, the southern portion of the county  is not expected to experience anything measurable. Winds will be the main theme with Southwest gusts increasing to 95 mph over the crest, while winds in the residential areas could reach 50 mph.  A wind advisory is now hoisted for the county.

New 12z nam/wrf  shows a splitting trof off shore with the main baroclinic band over Northern Ca. Topo lift will allow for some showers for Mono County by late afternoon. The freezing level over Mammoth is 10K today….9.5K Friday and 8.5K Saturday. Snow levels generally are some 1500 feet to 2000 feet below this level. The heaviest precip will be on the west side, Tahoe north today. Highs in Mamoth today will be in the 40s vs. low 50s yesterday.

A baroclinic band will weaken somewhat Saturday as the splitting process continues. There after…a double structured baroclinic band develops Saturday afternoon with one band mainly north of Tahoe with the other over the Southern Sierra. CRFC gives Yosemite a QPF of .1 Friday and .2 for Saturday.

At 10:1 possibly an inch of snow Friday for Mammoth Mountain and 2 inches Saturday.

The temp should pick up Sunday as the southern branch and main closed/cut off low gets the boot inland. Some 3 to 6 inches of snowfall is currently expected for Mammoth Mountain Sunday afternoon into the evening.

As mentioned above…..with the freezing level lowering through Saturday….it is natural to believe that our high temps will lower into the 30s by Saturday as well.

The Dweeber………………………..:-)

Reference Glossary of Weather Terms