Subtropical Moisture Associated with a Rex Block Pattern will stream in later today and tonight with a chance of Snow Showers Thursday through Friday…….Expect a Partly Cloudy Weekend into Next Week
Wednesday January 28, 2015
Posted at 9:17 am by Howard
More light showers are possible the next two days as a weak subtropical baggy trof spreads mainly high clouds throughout CA. …..The snow level will range from 6500 to 7,000 Ft. No significant accumulation expected. The weekend outlook for Saturday and Sunday shows Gusty Ridge Top winds as an upper ridge builds in. Winds will initially blow out of the NE, then back from the north Sunday. It will be breezy as well over the Valleys of Mono County where there are north/south orientated valleys. As the upper ridge at 500mb build over CA, temperatures will warm again over the CA State next week.
The REX Block Morphs back to a full latitude ridge over the far west as a Positive PNA pattern strengthens at the same time. Although the Daily Runs of the various longer range models show phantom systems both approaching and moving through the mean ridge position or in inside slider fashion, they should for the most part be discounted, from bringing any meaningful precipitation to CA. The next transition based upon the 21 day cycle will be more toward the middle of February.
Dr Howard and the Dweebs………………………………….:-)
Although the pattern has changed a bit from earlier in January, showing more of a REX Block, IE A coupled Upper High with an Upper Low to its south, the pattern is still a dry one for the Eastern Sierra. The biggest indice that stands out the most is the super strong positive PDO teleconnection which hit a record high of 2.51 last December. I expect that this teleconnection will prove to be very high again for January. One part of the +PDO is warm water along the west coast. Warm water along the west coast is, at the least, supporting other teleconnections in keeping an upper ridge extremely strong over the far west. This indice probably has its greatest effect over the Northern Hemisphere during the darkest months, like Mid Nov, through Mid Feb. I would expect that as the days get longer and the Sun gets higher in the sky, later in February and March that the system of teleconnections that are responsible for the dry pattern over the state will break up as we head toward Spring and Spring itself for at least some badly needed precipitation.
For those that want to read a Paleoclimate study on the Climate of CA, here is a good study and link. This study does offer an insight to past climate here in the eastern sierra. http://www.waterboards.ca.gov/waterrights/water_issues/programs/bay_delta/deltaflow/docs/exhibits/ccwd/spprt_docs/ccwd_malamud_roam_etal_2006.pdf
In reading through the dissertation, it makes reference to the affects of the little ice age and its effects on the Eastern Sierra. It was noted that during the 17th and 18th century that the Eastern Sierra as well as the Great Basin turned especially cooler and wetter. As a side note, the Little Ice Age was associated with the Maunder Minimum, in which was a period of time with either very low or none existent Sunspot Activity. This went on for about 80 years.
Coincidently, we are currently going through a solar hibernation according to David Archibald, a solar scientist. As we come off of the double peak over the past few years, it may be that over the next few years, the eastern sierra actually goes through a period of greater moisture and cooling, if sunspots indeed disappear later in the current cycle 24. The Dweebs will give it another 2 to 3 years to see if we turn extra wet again. This maybe wishful thinking, but it is worth noting!
Expect A chance of showers Thursday thru Friday with little accumulation of new snowfall. Highs in Mammoth will be in the 40s reaching low 50s by this Sunday. Night time lows mostly in the 20s. Will update weather for the next week this weekend.
Dr Howard and the Dweebs…………………..:-)
Weather Becoming Unsettled this Week as the West Coast Upper Ridge gives way to two weak Subtropical Systems……Some Light Snowfall expected Tonight and Tuesday….Cooler Weather this Week….
Monday January 26, 2015
Posted at 8:43 am by Howard
Record High temperatures were broken yesterday in many areas of Eastern CA. The combination of the lack of snow pack and high pressure aloft over Northern CA allowed these highs to be exceptionally greater than would have been, had we had a larger snow pack.
Broken high temp records occurred in other areas as well like the Owens Valley. Bishop had a high of 76 Sunday breaking the old high temp of 71 set back in 1984. Mammoth’s high temp was 61 breaking the old high of 52 set back in 2007. South Shore Tahoe record high was shattered with a high of 66 as compared to 57 set back in 1982.
A classic “Rex Block” weather pattern developed over the far west this weekend bringing record high temperatures for the Eastern Sierra. The Observed Pattern is highlighted by A strong Anti-Cyclone over Northern CA, while the southern portion of the REX (an upper low) was located to the South at 25N/130W. (Off Central Baja,MX.) The progs today show the upper ridge portion moving east today, allowing the upper subtropical low to lift north and east into CA Tonight and Friday. Latest Satellite motion shows moisture and PWAT increasing over Southern California at the moment. The progs move this moisture north into the Eastern Sierra tonight and into Tuesday. Precipitation is expected to be light, between .25 and .50 of an inch for QPF from this system. There will be no Orographic’s with this system for Mammoth Lakes. However, you can not rule out some heavier convective showers with some isolated heavier amounts over the Southern Sierra. Expect between 2 to 4 inches of snowfall over the upper elevations between tonight and Tuesday night with another couple of inches possible between Wednesday and Friday. High temps on Tuesday will be in the mid 30s. lows in the 20s
The outlook shows another but weaker system moving through Thursday/Night. with a few showers. The weekend outlook looks partly cloudy and dry with warmer temps….
The 21 day cycle completed its transition from one dry pattern to the next. The Longer range outlooks are in agreement with the ridge trof pattern lasting another 2 weeks over the CONUS.
Dr Howard and the Dweebs………………………….:-)
Modest Jet energy now moving through the High Country Aloft will spin up into an Upper Low over the weekend off the Baja Coast….As a Strong Upper High builds into CA Saturday and Sunday it will become quite mild in the High Country……Showers are expected Tuesday through Thursday….
Friday January 23, 2015
Posted at 8:10 am by Howard
Latest Update 1-22-15 from DWP for the Mammoth Pass area is 18% of normal to date and 10% of normal for the April 1st average. According to DWP, we are very close to being dead even at this time with the drought year 1977. According to Bob Sollima, (Back Country Bob), there is only 4.00 up on the pass which is even less than the telemetry is indicating. So it is possible that we are drier at this time than that year. Bob, if you are reading this, please email me and let me know the source of your data or measurement.
I just looked at the reanalysis 500mb maps between 12/1/76 and 6/30/77. There are striking similarities in that time period, both to ENSO, the PDO and the “AO monthly mean”. The AO monthly mean was a -2 sigma vs this Dec/Jan -1 Sigma. What happened in the winter of 1977 was that the long dry winter began to break beginning the middle of February with decent storms the 4th week and good storms in March and April. I would say from the reanalysis 500mb charts that it was a cooler spring and unsettled, well through May.
The biggest change of course for Mammoth is that Mammoth Mountain installed snow making several years ago which has made all the difference one can say. Chatting with those that ski every day, they have told me that they continue to enjoy themselves as the mountain freshens up the snow on many runs on a regular basis.
In 1976 without snow making, we had a few early storms in the Fall, then virtually nothing for weeks. I understand that the mountain opened early that ski season then closed for a few months then re-opened again in either late February or March.
From Fridays discussion:
Sky’s over Mammoth were clear this morning and as a result….Low temperatures this morning chilled well down into the 20s. The current analyses at 500MB showed the flow at 300MB out of the NNE as a weak upper jet dives south associated with a shearing trough. Gusty winds over the crest in the 50MPH range will continue today through Saturday AM. The energy associated with the upper jet will move south off the coast of BAJA and spin up into a closed upper low at 500MB. Though the process, dynamic lift will occur which increases the PWAT within the system over the weekend. In the meantime, a strong upper high will build into Northern CA Saturday and pinch off a closed anti cyclone Sunday. Through the process, a rapid decrease in the ridge tops winds will occur Saturday. Additionally, a rapid warm up will occur from the mountains of the Sierra Nevada to Southern CA as the upper flow sets up a moderate Santa Ana condition Sunday over the LA Basin as adiabatic lapse rates rule their. It will be beautiful in LA with highs in many areas in the 80s on Sunday. It will be in the low 70s in Bishop and near 60 in Mammoth Sunday.
The Upper Anti Cyclone will progress into the Great Basin/Nevada Monday and allow the system spinning up off the coast of BAJA to lift north into Southern CA Monday night and into the Central Sierra Tuesday. This is neither a strong storm, nor does it have a significant cold air source. There is a lack of strong dynamics to provide meaningful precipitation for the Central Sierra. At this time, it is dubious on the actual main moisture channels/trajectory. So in the meantime, showers are the best way to cover the outlook here in the Central Sierra Tuesday into Thursday. It is possible that we could pick up a few inches of snow over the upper elevations or even more if the main trajectory of moisture is more north somehow. Stay tuned, I’ll have another look and update Sunday.
Above Normal temperatures and below normal precipitation are both indicated in both 6 to 10 and 8 to 14 day outlook’s. With that said, there will be some precipitation over the next two weeks. However, at this time, no storm cycle, (5 or 6 feet+) is in the short, medium or long-range. The Dweebs expect that this dry winter will break at some point beginning sometime in February and extend into March and April. This is based in part on the CPC’s weeks 3 and 4 outlook as well as statistically, the driest winters do.
It is the opinion/belief of this WX Dweeb that this resilient upper ridge of the past 4 years over the far west CONUS, is a fundamental reaction to a teleconnection/s of unknown origin, that has yet to be discovered. Its resulting persistence and sigma in this short period climatic variation is proof of that. The fact that precipitation most often, if not always returns in the late Winter and Spring is part of the disruption of that phantom teleconnection.
Dr Howard and the Dweebs……………………………….:-)