Upper Ridge Strengthing over the the Far West……PNA begins to go positive…..So far….no meaningful let up in sight for a pattern change……may get worse before it gets better……
Tuesday December 24, 2013
Posted at 12:36 am by Howard
This is the Dweebs year end opinion edition:
I guess I can say that that for the most part that all long range forecasts…. I mean all have gone 100% bust this Fall. So with that in mind…..I too have a prediction! I predict that for the most part, this Winter forecasts will have a 50-50 chance of being wrong as well! So what does that mean? A 50/50 chance of being wrong? It means anything a long range forecaster wants it to mean after the fact!! You will find that out at the end of this snow year which ever way it turns out! I mean that if anyone pays anyone to know what this winter is going to be, they deserves what they get!
The fact is, this is a La Nada year. There is no bias in either El Nino or La Nina! So the ability to forecast this winter is pretty slim. In this case at 50%-50% in Central California. That is why the National weather service gave Central California precipitation, equal chances. Equal chance of 100% percent of normal? No…..it means that they do not know what kind of winter this is going to be because there is little or no bias! To complicate matters further, the QBO is positive, meaning that the AO and NAO teleconnections will be mostly positive…..which by the way is what this Fall has been for the most part. When this teleconnection is positive, the flow of air out of the Arctic meridianally is much less frequent or not at all. However…Now as of last the last several days of forecast model runs………… they show the AO to become negative. That means that it is going to get very cold over the eastern half of the US. What does it mean for California? Probably nothing, as the relationship of the AO is not linier in its weather effects in California. So praying for the AO to go negative is like praying to win the lottery. Its possible, but would you really spend your last dollar trying to win it?
Now with all that said, there is still plenty of time for this winter to come back…… When that might be is not known…..The CFS is interesting for the 2nd half for January….but I would not go to the bank on that….No.
If I sound cynical this evening…your probably right…..
I hope to feel better in the morning……………………………..
Cold Upper Low Now Exiting through Northern Mexico…Leaves some light snowfall in the Process…Gusty winds over the Crest….Cooler Temps……
Friday December 20, 2013
Posted at 5:58 am by Howard
Friday Update: official word 4 to 6 inches on Mammoth Mt….. storm total with snowmaking going on all day Friday and Saturday weather permitting….
Next update Tuesday AM…..
Mammoth received some light snowfall Thursday. Although it was at the lower end of what was hoped for, about 2 to 3 inches accumulated here near the Village at Mammoth. Mammoth Mountain probably received between 3 and 5 inches. However they will update a bit later this morning.
the upper flow over the weekend will be out of the north with the upper jet over Nevada. this is a cool dry pattern. the best that can be said about it is that it will remain cold enough for snow making every night and some in the daytime today Friday as well.
By Sunday the an upper ridge builds in for the west and we become inverted again early next week. It appears that although there may be a few small systems that will modulate winds and temperatures from time to time, it will remain dry through the end of the year according to the guidance. There is some suggestion by some of the guidance that a slight shift in the pattern will occur by years end. That a weak storm or two might slip through the mean ridge position or a slight retrogression in the long wave ridge position may occur in the first week of January. However, whatever change occurs, it will most likely not be significant as there are much less ensemble members that are showing it as compared to others that are just plain dry.
For you long rangers that have the need to know what the future may hold, the Climate Forecast System (CFS) has indicated the following. (I will add as a caveat, that this experimental at best and is not to be relied upon for planning purposes).
For Mammoth Lakes (QPF)
1. From the 22nd to the 27th of December (Dry)
2. From the 27th to January 1st (Dry)
3. From Between January 1st and the 3rd. Between ( .1 and .15)
4. From between the 1st and the 5th of Jan (.3)
5. Between the 5th and the 8th (.25)
6. Between the morning of the 6th and the morning of the 11th ( . 2 to .25)
7. Between the afternoon of the 8th and the afternoon of the 13th. (.35)
8. Between Jan, 13th and the 18th (1.2)
9. Afternoon of the 18th and the afternoon of the 23rd (1.3)
10. Afternoon of the 23rd to the afternoon of Jan 28TH (.75)
11. Afternoon of the 28th of Jan thru Feb 2nd. (.7)
Total for January (QPF) between about 4 inches ( This does not include the first few days of Feb.)
Again this is experiential and not to be used for planning purposes
The average snow to water ratio is about 10:1 here in Mammoth Lakes.
Based upon the CFS guidance we might think that the chances of significant snowfall might increase about the middle of January.
In that I do not have access to the ECMWF Monthly Precip I can not compare to the CFS. However, my access to the upper height pattern at 500MB FOR 30 days and the 500MB ENSEMBLES suggests that
the CFS is too Wet…
Dr Howard and the Dweebs………………………:-)
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……………………….:-)