Atmospheric River Event Continues……More Flooding for Northern Ca and More Snow Headed for The Upper Elevations….
Saturday December 1, 2012
Posted at 10:07 am by Howard
Heaviest precipitation “to begin” between 10:am and 12:00 noon Sunday….
Main Lodge at 9:00am…..Rain/Rain Snow Mix…… Freezing level 9800 will lower to 9500 by about 10:00am then down to 9,000 ft by 4:00pm…… ALL Snow at/above McCoy……>>>> No micro physical processes at work to promote snow level lower then expected. Column not saturated from either Dendritic Crystal Growth zone to 7000ft….Dry slot at 750mb. SEE: http://weather.rap.ucar.edu/upper/oak.gif
At 10:00am it was 36 degrees at 8200ft. Most ly rain and rain snow mix at the main lodge and Snow at McCoy Station. The out look for today is for falling temperatures the remaindere of the morning and through the afternoon. The snowlevel will be falling to 8000ft by 12:00 Noon and to 7,000ft by 4:00pm.
The National Weather Service has hoisted a winter storm warning above 8000 for this afternoon until 7:00pm this evening for hazardious driving conditions in the Towns of Mammoth and June Lake as well as the higher passes of 395 through out Mono County such as Conway Summit and Dead Man Summit just north of the CrestView Station. Expect between 10 and 14 inches above 8000 ft and 4 to 8 inches above 7000ft by 7:00pm tonight.
12 Central and Northern Ca rivers at flood stage…..Inc Merced River….Well Southwest of Sentinel Dome.
|10.0 Feet||Western portion of North Pines Campground, located at the east end of Yosemite Valley between the confluence of the Merced River and Tenaya Creek, begins to flood. Water rises to the base of the swinging bridge downstream from Chapel Meadow.|
|10.5 Feet||Water tops the swinging bridge downstream from Chapel Meadow. Overflow from Woski Pond floods access road (Northside Drive) leading out of the west entrance of the park.|
|11.5 Feet||Sewage pumping relay station at North Pines Campground becomes flooded.|
Can you smell the Pinnapples? You will need Flash to see this….See: http://www.ssd.noaa.gov/goes/west/nepac/flash-ir2.html
North of Hawaii the PWAT is over 1.5 inches
At 10:30AM Saturday….Rex Block Config continues west of Hawaii with a static 500mb upper high 50N/169W and upper closed low 36N/170W slowly progressive. Nice tropical tap southwest from this mid latitude low to about 15N with PWAT 1.50+ Inches north of Hawaii. This is the feeder for the confluence east along 35N to 42N then east to the California Coast. Confluence takes place about 150 west then shifts east with time this afternoon as main PJ short wave bottoms out into STJ at 40N. At the same time…it spins up to about 150knots before heading east to the Ca coast. The Rt rear entry of the Upper Jet looks to clobber Central and Northern Ca Sunday. The good news is that the models are about 6 hours slower with the cold front and not as warm today during the wettest part of the storm Sunday afternoon. It appears that the freezing level will be about 500 feet lower then earlier forecasted. So although we never do get to the cyclonic side of the PJ upper jet, any rain that may fall at the main lodge will be much more limited time wise and it is likely that another couple if feet may fall Sunday afternoon during the height of the storm as temps are forecasted fall during the heaviest part of the storm now.. I will take another look at this either tonight or for sure in the morning. The OAK sounding will be something critical to look at to see the possibility of Micro Physical Processes at work. If the air mass is saturated and at least -15C from the dendritic growth zone then saturated down to 750-800mb and the 0C line down to at least 700MB, we could get snow to much lower elevations than forecasted. Will need the 12z Sunday OAK Skew T to see.
I see another 3 feet plus above McCoy Station either way…..
Both the STJ and Polar Jet separate again Monday as they both shift north. A weakening subtropical jet brings the slight chance of showers to the Central Sierra Tuesday night and Wednesday as the Rex Block breaks down mid week and the pattern goes into transition. I see a fair weather period with less cloudiness Thursday into the next weekend. The flow over the Eastern Pacific is Northwesterly with the upper jet well to the north.
Amplification is forecasted by both the American Models and Canadian while the European has something a bit more interesting longer range with much more retrogression in the upper high and a very deep cold low developing in the Northern Gulf of AK. This gets accomplished as a deepening cyclone develops off the coast of Asia builds the down stream upper ridge over the Bering Sea.
Lots to watch in the coming weeks as long range forecasters are scratching there heads wondering what’s happening?? 😉
Dr Howard and the Dweebs…………………..:-)