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……………………………….:-)
While Split Trof moves through CA bringing high cloudiness….There is an interesting feature in the models about a week away…..
Tuesday January 20, 2015
Posted at 5:02 pm by Howard
The ever resilient ridge of high pressure is still hanging out over the far west keeping CA locked into a historic drought of middle age proportions. Really? Maybe….
I can not seem to get any straight answers for those in the know. I have heard 1200 year drought. I would love to see the data on that! Some one needs to present to the LA times a tree ring study on that one for all to see.
I have heard of 2 extreme dry years in a row but this dry and now 3.5 years. I do not know or have heard of anyone taking water measurements in CA back in the 1500, 1600 or 1700s. Some CA natives back then may have been into Weather. Possibly written in the Petroglyphs? Seem like a lot of work just to tell a dry story….especially one without much humor.
But during the little ice age in the late 1600s, might have CA been this dry? It is all about the wave length. A deep persistent polar vortex that descends out of the Arctic via Canada over the eastern half of the CONUS that would freeze the Great Lakes and inlets of the east coast. Would that not bring drought to the central west coast inland? Think about it. It all about the planetary wave length. A Big Omega Block with the polar vortex in the east and a mega ridge even stronger than this one out west followed by a western deep Trof south to Hawaii. Where are there tree ring studies for the mid to late 1600s during the little ice age for CA? The bristle cone pines where growing in the Bristle Cone Forest on White Mtn. I wonder what the research shows for that time frame.
There is an interesting twist in the GFS the last few days. It is worth mentioning because the new higher Res T1534 GFS shows it as well as the new 12Z ECMWF.
This is the scenario. The forecasted Ridge that is expected to build into California this weekend becomes extremely positive tilt. Before it builds in, a shearing trof comes through the upper flow Thursday, then digs south off the Southern CA coast, well down over tropical Mexican waters. This Tropical/Subtropical Eastern Pacific low spins up…then lifts north into CA about next Tuesday.
This is similar to an early season tropical depression that comes up along the Baja Coast gets entrained into an approaching mid latitude trof, then spreads rains into Southern CA and eventually the Sierra. It is interesting to note that there is a PWAT pool of moisture up to about 2.00 inches to tap from. This is only worth mentioning as the new 6 to 10 day outlook is showing the possibility of something like this effecting CA next week. This would be a warm system with high snow levels. What aids the trajectory of the moisture is that the upper ridge progresses into the Great Basin providing the channel for the moisture into CA. I do not remember seeing something like this, this time of the year in memory.
On another note, we are at the end of the 21 day cycle and the Dweebs would expect the pattern over eastern pacific to go into transition. And…..it appears that it is beginning to do just that…. The first change is with the wave length. Once the new pattern sets up, the models will reset and we’ll see what kind of animal we have coming our way. We are talking February now which the latest guidance is showing to be wetter then normal. Let hope that is correct…..
Variable High Cloudiness expected for the MLK Weekend….Temperatures to Remain Mild through the Holiday….Then Expect Cooler Weather Tuesday and Wednesday…..
Friday January 16, 2015
Posted at 8:38 am by Howard
Friday 1:25PM Comments….
Just had a look at some of the key teleconnections this afternoon.
The PNA is currently positive and is why we have such strong ridging over the far west. However, in looking at the PNA by the 26th…. It is interesting to note that the 12z 1/16/15 ECMWF on the 26 of January has the PNA index at about -2.5 Sigma from neutral. What I like as well is that the new GFS Upgrade T1534 12z run today has the PNA at -2 Sigma. The old GFS has been retired as of early this week. As far as the EPO index, the ECMWF goes from +2 Sigma today to -2 Sigma but the GFS Upgrade goes from +2 sigma to neutral for the 26th.
The (PNA) is the Pacific North American Pattern and in its negative phase is usually associated with more trofing over the far west. The (EPO) eastern pacific oscillation is associated with heights building over Alaska further west and is often times associated with retrogression. So things maybe moving in the right direction during the last week of January into February.
The updated forecast for the MLK holiday weekend shows variable high cloudiness through Sunday with Gusty Winds at times over the Sierra Crest, breezy at times in the Town of Mammoth. High temperatures will range in the 50s at resort levels and 20s and 30s at night. The further outlook is dry for the most part and cooler as well.
A blocking ridge of High Pressure aloft will remain off the Southern CA coast through the middle of next week. The upper jet favors Extreme Northern Ca, OR and WA. With the upper jet this morning over Northern Ca, gusty winds are occurring over the Mammoth Crest to 60 MPH. It is likely to remain quit breezy today and tonight over the crest. Another short wave will move onshore later Saturday. This will bring more breeze to the upper elevations as well as more cloudiness to the Mammoth area. However, these clouds have little in the way of moisture and outside of a slight chance of a shower, precipitation will remain 100s of miles to the north of us.
The short, medium and long-range shows well below normal precipitation through the end of January. However, with that said, there are increasing signs that during the last week of January and into February, that retrogression with the upper blocking west coast high and a gradual weakening of the Subtropical Eastern Pac Upper High will occur. This is according to both the new T1534 now operational GFS and latest runs of the ECMWF…32 DAY 51-MEMBER ENSEMBLE CONTROL (EPS) Note: There is no established pattern yet, just retrogression with many of the ensemble members.
PS There is no truth to the rumor that it will be dry through Mid February because the forecast skill for weeks 3 and 4 is no better than about 50/50.
Dr Howard and the Dweebs………………………………..:-)
On a bright Note….
Check out the latest CFC Forecast:
CFSv2 Forecast of Weekly Climate Anomalies
Wouldn’t that be nice!
Some Unofficial Mammoth Pass information provided by amateur Hydrologist Bob Sollima “Back County Bob” as it pertains to local history….
According to Bob…..
“At this time, we are about even with the 1991 year mid-January. 1991 was the second worst drought on record (for Jan-Feb)…then the March Miracle that year which propelled the water content to 75% of average at (water) year’s end on April 1st. If Mammoth Pass does not pick up any additional precip by the February 1st (2015) survey, we would be in danger of having the lowest February survey result in history…even less than Feb 1977. The 1977 winter at this location only gave us 8.6 inches of water content at April 1st TOTAL. As the Pass sits now, we have about 4 inches of water stored in the snowpack there…about 50% of what was there this time last year (2014) & about 50% of what we had at this time in (2012). 4 inches of water content (at this point in time) equals 1977. Average for this date is about 25 inches water.”