Upper Ridge Parked Over California will Give Way to a Very Weak Coastel Slider…..Some extra wind over the Upper Elevations Friday Night and Slightly Cooler Temps Saturday……The Outlook is Still Dry Through Years End……
Thursday December 26, 2013
Posted at 9:29 am by Howard
It’s been fun to watch the week two progs of the ECMWF, GEM and GFS. After looking at them for the past few days, they all have the pattern transiting toward retrogression. The key will be where the upper high closes off. I do not believe that we can tell at this point or even possibly by the end of the new week where that will eventually be. However, teleconnection wise, if the Upper high ends up over Eastern Siberia, we’ll stay with fairly high heights along the west coast and mostly storm free. The ECMWF and GEM show that. However there is hope that it will close off further east over western Alaska. That teleconnects more favorably with a southern branch of the westerly’s reaching the central west coast. As mentioned in my past discussion we will not have a good idea where that will be for about another week. There will need to be a lot of water under the bridge flow though between now and then.
Keep good thoughts and the Dweebs will report on a regular bases……
Friday Afternoon Update: (Long Range chatter)
The CFS has been suggesting a change to the possibility of some precipitation beginning between the 8th and the 15th of January. There after on and off through the month of January. It gives something like 2 to 4 inches of water for the month for our area. Not a big deal for January but anything now is a big deal right?
Remember, this is the CFS, it is not really a weather forecasting tool. It is used more as a general interseasonal outlook. It is based upon Forecast Anomalies from Model Climatology. Now coming off a pattern like this, it is more of an outlook for Hope and Change. I know you all know about that….right?
The fantasy charts at 500MB during week two have for the past few days begun to show a change during the end of that timeframe. I see it in the GFS deterministic and the ECMWF control runs. Today’s 8 to 14 outlook for the CPC indicates that retrogression is going to take place week 2. I’ll take their word for it. At the least it means an end to the persistent ridge over head. When you get retrogression, you usually get amplification upstream and with amplification you can get undercutting of the jet stream underneath…..especially with January’s strong upper jet. However, the Dweebs have always said that we can go from one dry pattern to the next. Or we can get a storm in here, in-between. So what kind of change it is going to be no one knows for sure at this time. I will say that it is a good sign that the global models are following in step with the CFS thus supporting whatever the CFS has been touting….a pattern change week 2. Todays 18Z GFS had it as an “AR” (Pineapple Express) Pretty funny Huh….
What I can tell you is that you are all going to hear a lot of positive rumors out there over the next 7 days about a developing wet pattern. Be careful in buying into this one. I am going to tell you to keep your heart on this change, until what ever it is gets into the 5 to 7 day period. That’s because you just don’t go through a pattern like this and all of a sudden it starts dumping like it’s never going to quit. We are going to start seeing a lot of different scenarios in the global models and the spread in the ensembles is likely to get pretty out of hand before too long. However, in time the spread will come together and that will be the time to set the hook! What ever develops from this transition, we likely not know what it is for another week.
Stay tuned…….and be thankful for the great snow making system on Mammoth Mountain……
Dr Howard and the Dweebs……………………:-)
Upper ridge will hold into first week of the new year insuring warmer than normal weather for California and a persistence of dry weather. In the meantime a small feature will slide down the coast off shore. It is moisture starved and will only kick up some upper elevation breeze and some high cloudiness Friday into Saturday AM. No measurable precipitation is expected.
Expect high temps (8000 feet) in the low 50s except Saturday when it may be a few degrees cooler…
In the longest range of guidance, the ECMWF does try To break the dry spell toward mid month. However the GFS is still dry with no end in sight to the current pattern. As a side note it is noteworthy that although the (AO) Arctic oscillation is becoming more negative, there is still no change in California Weather forecasted. (None linear connection)
Let hope for the best and think positive in the European model. At least it is trying to give us some snow toward mid January. As of note, this is the driest start to the snow season since December 1999.
The latest ECMWF run now has (Tri) positive 500mb height anomalies built over 3 long wave trofs…. hemispherically. The Ridges are connectable from the Alaskan ridge to the North Atlantic, the North Atlantic to the northern Asia ridge and over the pole to Alaska. This essentially traps troughs in the far east, over the eastern US and central and western Europe. At the sometime, it traps the west coast ridge as well. This is a very stable pattern and one very difficult to dislodge, especially in January.
Upper Ridge Has Adjusted East enough to Lock us out of Storms for the next one to two weeks…..No Let up in Sight within the 14 day period……
Tuesday December 24, 2013
Posted at 8:49 am by Howard
For the 7th time since Folsom Dam construction was completed in 1955, the reservoir has dropped below 200,000 acre-feet in overall storage. The capacity of Folsom Lake is approximately 977,000 acre-feet. The record low occurred in the Summer Fall of 1977…and was just below 150,000 acre feet.
The Winter of 1976-77 was the driest year on record for Mammoth Mountain. We did not have snow making that year….
Earlier in the Fall we had an upper ridge that would allow California Sliders to bring wind and cold Weather to our region. It appears now that the upper long wave ridge position has moved far enough east for the PNA index to go positive. This makes for strong temperatures inversions and freezing levels in the 11,000 foot range. I expect the Freezing level to pretty much remain near or above 11,000 through the end of this week. Thus strong temperature inversions will rule with air quality degrading over time…. For the most part we are locked out of precipitation for the next two weeks and possibly through mid January. There is no MJO activity forecasted through the 6th of Jan to change the pattern. The pattern is very stable with ridging in the west…..The east will become colder with time……even though the NAO is still positive. The (AO) Arctic Oscillation is growing negative. The word is that San Francisco is about to have its driest year on record….
Although there is a weak upper low coming though the ridge this weekend bringing us a slight chance of showers….the pattern is a dry one for the state and there is nothing at this time that can change it anytime soon…..
Expect high temperatures in the low 50s in Mammoth with lows at night in the 20s and low 30s. Lower elevations of the county will be in the teens for the most part, locked under temperatures inversions. Mono Lake Fog and Pogonip will increase over time…….
Through all of this…folks are having a great time up on Mammoth Mountain as the mountain had been making snow for the past two months….
Dr Howard and the Dweebs……………………..:-)
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……………………………..