West Coast Ridging building in with strong height rises and off shore flow…..Fair mild weather to rule through the weekend……Retrogression to begin Sunday with cooler weather along with gusty winds over the crest later in the weekend…..
Wednesday February 11, 2015
Posted at 12:34 pm by Howard
The Dweebs been watching the Ensembles Control of both the ECMWF and GFS that last few days. Both now seem to have discontinuous retrogression in play over the next 10 days. I guess that you can say that with the upper ridge adjusting slightly west Sunday and with some cooling next week that it has begun. However, it really does not go anywhere of significance until about the 24th or 25th. This is within that last week of the month that the CFS has been touting change for the end of the month. And…although there are timing differences, there is significant retrogression that last 4 to 5 days prior to the end of the month. That is a good thing!!
The main suggestion is that there will be a cold inside slider 1st, then a full latitude trof near the west coast afterword’s. Would that not be nice. Not taking it seriously until it gets within at least the next 6 to 10 day period.
Anomalous weather continues across the CONUS as a very strong ridge remains anchored over the west coast, building northward to the Arctic, providing both extremely warm dry conditions over the west as well as creating a direct path for polar air to sweep SE through the Western Great Lakes. It then spins up into a northwestern Atlantic Nor’easter dumping more snow across New England and strong blizzard conditions as well. So as strong as the anomalies for warmth and dry conditions are across the far west, it is just as anomalous for parts of the east with the persistence of Snow, Wind and Cold for New England. The deviation’s for warmth of 850mb temps for this time of the year are very high over the central eastern sierra. High temperatures ran 24 degree above normal Friday at 8000 feet. Mammoth Weather had a high of 65 Friday at 1:30pm. Normal high is 41 for this date.
This is all part of the same western hemispheric system and wave length that the Dweebs believe is tied into by natural forces, due in part to the natural variability of ocean currents and tropical convection. Specific teleconnections have lined up like bars on a slot machine in a row 777777 with the odds well against it for this short period climate variation. It happened in the 1930s and that sequence may be happening now with the +AMO/+PDO connection. Unfortunately, the teleconnecting AMO is not as forecastable as the PDO. So we may not know how long this drought will last in the west. I have posted more information on the AMO-PDO teleconnection below….
As it stands, we are still in our winter mode and it may be that we will need to get closer to Spring until the system creating this drought producing weather….weakens due to the seasonal differences and its effects with the same teleconnections.
For what it is worth, there are still signs of a change during the last week of February. (Via CFC) Especially near the end of the month where there are still suggestions of another AR event. This has already been touted earlier this month in the Dweebs outlook.
PS Here is another climatic study on drought.
A robust but short-lived upper height anomaly is developing over the west coast at the moment. A moderate off short flow is expected for the Southern CA later today into Friday. Santana winds will be moderate to strong is some areas with low 80 to near 90 in the LA basin by Thursday then into Friday.
For Mammoth Lakes, our warmest day will be Friday with highs in the low 60s. Lows in the 20s and 30s. light winds are expected in town and some breezes will occur over the Crest out of the ENE. Later in the weekend the west coast ridge will retrograde west. This will allow systems to drop south into the Rockies and possibly great basin next week for cooler weather. Winds will come up over the crest by Sunday out of the NW.
At the moment, the pattern through Tuesday looks dry, however any further retrogression my allow trofing to develop over the far west and eventually the far Eastern Pacific. Some under cutting is also possible as both the EPO and WPO become quite negative again creating high latitude blocking. We may have some weather to talk about for the following weekend by early next week…… At the moment, the MJO is not cooperating with a weak signal….
The Dweebs have been doing some research lately on the connection between the AMO, PDO and droughts in the West. What I have come up with is a fairly strong signal when the AMO is in its positive mode. See the following links.
See two examples of research:
What is notable is that for the Number 1 example, the research was done during the negative phase of the PDO a year or two ago in which the AMO was positive. We had very dry conditions for most of CA during that phase. This year the PDO is strongly positive and the AMO Positive as well. This led to even worse conditions for CA. Although we did get a few AR events which I understand are more common during this phase.
The graph shows that the incidence of drier conditions over the southern part of CA is less with the +PDO and +AMO combo as there tends to be a higher incidence of a low/mid latitude storm track. IE pseudo warm ENSO “like” conditions. That is why there is less bias under the current teleconnecting scenario for Southern CA. Otherwise, another example of the +PDO/+AMO combo was the big drought of the 1930s. IE the Dust Bowl years.
There is some indication that the AMO may go negative by next winter but not guaranteed. That would better for the northern half of our state for a wetter winter including Mammoth. With that said, the research also shows that the “predictability” of the sign of the AMO is poor at best.
Want to track the PDO and the AMO? The links to the induces are on the my favorite links page.
What is the perfect scenario for cool/wet in the west?
It is the -PDO combined with the -AMO. Up to 80% chance for CA to be Wet.
As Wet Windy Pattern comes to a close…. Drying trend develops with upper ridging taking hold again over the far west…milder temps on the way…..Next pattern change about the 16th…….
Monday February 9, 2015
Posted at 10:24 am by Howard
Notice: Regarding Victim’s of the Swall Meadows Fire:
As many of The Dweebs know, there was a disastrous fire last Friday that took 40 homes in the Swall Meadows area. Many of these family’s need housing at this time.
If you know of any or have friends that you would like to contact to see if they would like to rent their Mammoth or Crowley Home at this time…..
Please contact State Farm in Bishop, as they are gathering a list of homes that can be rented for 6 months or so.
State Farm in Bishop
The Dweebs had a look this morning at the Key teleconnections over the high Latts that can shape our weather future here along the central west coast. The AR event for Central California brought badly needed rainfall to the northern half of CA and added more water to the exceptionally low reservoirs. Over the next 6 to 10 days the western ridge is still in control of our temperatures and to a great extent precipitation. Looking at the teleconnection of the WPO over the next week, it becomes very negative once again. In fact this mornings GFS shows the WPO dropping to a whopping -5 sigma on the 16th. The ECMWF also shows the WPO quite negative, although not to that extent at -3.5 sigma at the same timeframe. The negative sign of WPO (Western Pacific Oscillation) favors higher than normal heights over the Bering Sea between AK and Siberia. The creates blocking and a suppressed Asian Jet. This was part of the cause of the “AR” and Pseudo pineapple connection last week. The strength of the -WPO is forecasted to be stronger this time. That is why in a previous discussion the Dweebs indicated “AR Redux” around the 18th or 19th of February. And if it does develop, it is likely to be another warm precip event, preceded by strong winds. Why do I think that it will be preceded by strong winds again? Because with the ridge in place, you are going to get much warmer than normal temperatures that are antecedent. If the upper jet’s entry is again to the north of us, convergence aloft, coupled with moisture and precipitation banking up on the west side of the sierra from an “AR” is a strong signature for lee side high wind events for the Eastern Sierra. I’ll also be watching the Wheeler Phase space to see if it goes into Phase 8 again later next week…..
PS I spoke with Cliff Man this morning of Mammoth Mt Operation’s. He said that the storm did bring very beneficial snowfall to the Mountain. Although it was heavy and wet, the upper mountain has improved remarkably in its coverage, 100% according to Cliff Mann.
Sounds like it will be great skiing and boarding for the Presidents Holiday Weekend.
One More Wet System on the way for Sunday PM…..This Ones a bit Colder on the Finish for More Accumulation in Town by Monday AM…..Then Fair Weather returns by Tuesday……
Saturday February 7, 2015
Posted at 9:34 pm by Howard
Storm total in the form of water was between 3.25 and 3.50 inches of water over the upper elevations…. Not nearly as much as touted from all the guidance..
Mammoth Mt did manage to pick up at the 9000 foot level, 4.5 inches of snow early this morning. Although unknown at this time, more accumulated snowfall is expected over the summit. MMSA did pick up close to two feet from the first storm over the Summit.
Additionally, the town only picked up a dusting as most of the precip was gone by the time the cold air got on here.
This is just an opinion in regards to the Fire in Swall Meadows. Although, there is an investigation ongoing for the cause of the fire, coincidently it is alleged that there were downed power lines in that area. It is a fact that wind and downed power lines cause fires every year. One of Reno Nevada’s biggest fires was started by downed power lines during a major wind storm in West Reno. When you combine downed power lines with 70 MPH winds and tinder dry forests, you get an explosive condition. We here in Mammoth worry about a fire starting on the west side of the sierra blowing east, when one of our biggest concerns “should be” from downed power lines in our back yards. Although most of Mammoth has buried power lines, there is still plenty of power poles that are not. There is no reason for this other than Edison not wanting to spend the money to bury them…..
Overall no microphysical process took place in this pattern. The winds mixed down to the Surface. The air mass became saturated and the snow level became within 500 feet of the freezing level. The next system is the same although there is some cooler air in back of the trof.
Next weather system is moving in quicker and will leave quicker as well. The QPF for Yosemite is down to 1.67 inches from over 2.5 inches as forecasted by CRFC. The Dweebs…remember the QPF by HPC was painted to be 12.00 inches of water. I doubt that we had anymore then 3.00+ on the pass however we still have tonight to go.
As far as I can see the models did a piss poor job in many parameters. On another subject, thank goodness that there were no fatalities in the Round Mt Fire where the official count from Cal Fire, of homes destroyed is up to 40 and still counting…. The fire at this time is 65% contained. Winds in areas along the Eastern Sierra from Mono County and to the north of RENO were clocked between 60MPH and just short of 100MPH. There was widespread wind damage for 100s of miles north with trees as large as 30 inches in diameter blown down. Some of the sierra crest station’s reported wind gusts to 134 MPH.
The freezing level is currently 10,700 and will lower to 10,000 by 4:00pm this afternoon. Once again the snow level like yesterday will likely be well above 9,000 to 9500 feet until tonight when the Freezing Level comes down. The majority of the precipitation will be Between 4:00PM and 10:00PM tonight. It will be all snow in town after 10:00PM tonight. Hopefully the crest will pick up 12 to 18 inches. It will be wet 7/1 stuff until tonight when it fluffs out lighter. In town, probably somewhere between 2 and 5 inches by dawn…. The QPF goes to 0 by 4:00AM so maybe a few isolated showers between 4:00am & 10:00am.
We then go dry in the 6 to 10 day outlook….
Wow what a wild 36 Hours. At Mammoth Weather the Dweebs picked up 1.52 inches of Water during a wet snowfall Friday Night into Saturday morning. I picked up about 5 inches of wet snow here at the 8200 foot level before it rained out. Wind’s along the highway 395 corridor were nothing short of disastrous with gusts to 100mph. The worst fire in my memory for the Eastern Slopes of the Sierra occurred in the Round Valley area up through Swall Meadows and Paradise Friday afternoon. On behalf of all the Weather Dweebs, our harts go out to all of you during this horrible time. Massive Power outages and communication failures developed from Douglas County in NV to the Inyo Mono county line. As of this time, cell service is still out for Verizon. Bridgeport also had its issues with SCE station burning down leaving Bridgeport without power. I am sure that there are plenty other stories, related to the winds that gusted 60 to 100MPH Friday afternoon.
Back to the weather:
CRFC shows about 2.5 inches of water yet to come in the Yosemite area. So expect another 1 to 1.5 inches of water here in Mammoth on the east side. That means that the upper mountain could get another 12 to 18 inches above 9000 and up to the crest on top of what ever they got the past 24 hours. In that it rained up to 10,000 today no telling what the upper mountain received at this time.
This next system has some colder air in it toward the end. It is possible that we might end up with 3 to 6 inches at the 8000 foot level by Monday noon. The snow level is not likely to come down much until about midnight. So it all depends upon how fast the colder air gets in here. If it is quicker, then we’ll get more snow in town. Once again the upper elevations of town will have the most accumulations…..
I do not have any information on what the sierra crest actually picked up.
Beyond Monday we ridge up and warm up for a fair weather period for the next 6 to 10 days….