Weak little Subtropical Low Ejecting through Sierra This AM….. bringing a few showers ahead of Main Coastal Slider For late tonight into Thursday Night….A few showers are possible Friday Night as well…..Weekend to be partly cloudy with moderating Temps…..Then possible back door cold front Tuesday…….
Wednesday December 18, 2013
Posted at 9:19 am by Howard
According to Jan Null CCM
As 2013 comes to an end it is very likely that this will be the driest “calendar year” in San Francisco since records began in 1849. So far only 5.59 inches have fallen since last January 1st; almost three-and-a-half inches less than the previous driest of 9.00″ in 1917.
For the present “rainfall season” (July 1st to June 30th) the total is 2.08″, which is the 4th driest on record.
So if you think that it has been strangely dry…you now have a clue…..
Thursday 5:30pm update..
Storm is mostly over but linger snow showers is a possibility tonight…..
Received about 3 inches at the 8200 foot level….a little more over the upper elevations…..good news is that its cold and snow making is in full swing tonight! Should stay cold through Friday night with snow making continuing…..
Nothing on the horizon at this time….Back door cold front idea has shifted east into the Rockies…….
Thursday AM: BACK TO REALITY!
All long range models were dry again for the first week of January 2014….this is what weather folks have to deal with…. That is why we just watch and wait for something that sticks within the 5 to 7 day period….
Snowfall was increasing this morning across the Eastern Sierra….for Southern Mono County the heaviest period of snowfall will be between 11:00am and 3:00pm. The heaviest Precip is indicated by the models over the Southern Sierra with upslope enhancement combining with a deformation zone from Southern Mono County south to Olancha. Temperature’s bottomed this morning at 26 degree at the 8200 foot level. I do not think that it will get much warmer then that today. As usual the strongest winds will be up over the crest to 60 MPH.
Here is your forecast for Mammoth at the 8300 foot level….
Today: Snow showers. High near 26. Northwest wind 5 to 15 mph becoming north in the morning. Chance of precipitation is 100%. Total daytime snow accumulation of 2 to 4 inches possible.
Tonight: Snow showers, mainly before 10pm. Low around 16. Northwest wind 5 to 15 mph. Chance of precipitation is 80%. New snow accumulation of less than one inch possible.
Friday: Mostly sunny, with a high near 36. Northwest wind around 5 mph.
Friday Night: Mostly cloudy, with a low around 23. North wind around 5 mph.
Saturday: Mostly sunny, with a high near 42. North wind around 5 mph.
Saturday Night: Mostly clear, with a low around 22.
Sunday: Sunny, with a high near 45.
Wednesday PM: 2:00pm
Seems like todays 12Z run of the ECMWF control ensemble has a pattern change in early January to wet. While this is certainly nice to see, at this distance….it is pretty dubious at this time. Will watch….follow and report as time goes by…..
5:00PM Wednesday: New 18Z GFS has closed upper high in Gulf of AK on January 3rd. Another promising sign but again too far out for anything serious…..
Some light showers developed over the Sierra this morning from a weak subtropical low being picked up by the main system coming in late tonight and tomorrow. The Upper low this morning is more of a nuisance forecast wise then anything else. A very small area of divergence aloft develops mainly south of Mammoth, produced a few reports of very light rain. QPF is up to a .1 max along the Inyo Mono Boarder. Although the models have had it for days…no QPF was associated with it until last night for today. Again this little wave will be through by this afternoon. Some snow showers possible over the higher elevations in the AM. No big deal….
Next stronger coastal slider is headed south tonight. This is one of those systems that will produce snowfall after the cold pool arrives. It will be the cyclonic upper flow that develops once the closed low forms that wraps back and gets us.. Upslope snowfall is likely and will produce precipitation during the morning hours and peak during the afternoon. Of note, the 500mb low center is on the coast and the 700MB upper low is east over the Central Valley in a better position for us.
Timing wise the snowfall is later then yesterdays thinking and light Snowfall may continue into Thursday night. Thereafter….were in an insider slider pattern which may actually produce snow showers again Friday evening or night……well see. Over all…..these are still storms in a dry pattern that shows no signs of changing. Snowfall estimates…….2 to 5 inches for Mammoth Lakes between 7000 and 8000 feet. As much as 5 to 7 inches up by the crest by Friday AM.
Extended range shows a back door cold front through Christmas Eve. It may or may not happen. If it does we may get a few showers………………and it will turn cooler again after warming up Sunday into Monday.
Dr Howard and the Dweebs……………………….:-)