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.