Unsettled weather to continue through this weekend and into next week as long wave upper trough remains a fixture over CA….
Friday May 15, 2015
Posted at 7:38 am by Howard
Monday AM: 920AM
Looks like another very active day today..
SPC shows a very strong 250MB Divergence-850mb convergence couplet over the Owens Valley at the moment associated with the 300mb cyclonically curved upper jet to the south. Best Surfaced Based Cape is located along the CA/NV border and SE Inyo County 500-1200 Joules per Kilogram (J/KG) according to the 14z HRRR 3km. (Rapid Refresh model) 850/500 crossover MULI lifteds are -3 over SE Inyo County. It all adds up to some strong thunder storms developing near Death Valley and to the NW of that area today. Best 850 surface deformation is over Southern Mono and south to Northern Inyo County. Good Thunderstorm potential over Inyo County Today…especially over the Southern Whites Mts…
The HRRR forecasts up to 300 J/KG over Mono County today and so air is not nearly as Buoyant and unstable. Nevertheless, deformation enhanced showers quite possible this afternoon for all of Mono County.
Dr Howard and the Dweebs…………………….:-)
Another system is currently moving in….snowfall to pick up later this morning and continue into tonight. Some thunder possible. Accumulations in town above 8000 about an inch with several inches over the crest today and tonight…..This pattern of on and off again rain and snow will continue through much of this coming week. It will be all snow on Mammoth Mt. More snowfall expected Monday in the shorter term…. highs in the 40s lows near freezing….
1. Increasing divergence over Mono County Today
2. 850mb deformation across northern NV
3. Strong 250MB Divergence over Mono County this afternoon
4. (Currently) storms are forming and training northward according to radar, north of Mono Lake along the south border of the Lion County and Mineral County line in Nevada. This is an area of strong 250mb upper diffluence.
Additionally, the SPC 850/250 differential divergence is showing an area of 850mb convergence near the Inyo/Mono County border with the 250mb divergence over Lyon County.
Here is an update on the current and extended pattern in general terms…
The Dweebs looked at GFS means this morning. IE days 3, 5, 8 and 11. The current pattern is likely to last through mid week. Looking at the larger scale, we can expect a continuation of the 500mb block over the NW territories of Canada through Thursday and the 500mb mean upper Trof over the far west. That keeps a rather unstable pattern for this time of the year with the combination of various areas of deformation and actual progressive areas of dynamic forcing aloft. The long wave trough is not as deep as it was with the system that brought up to 3 inches of rain over San Diego and 5 inches of snow to Mammoth MT last Thursday. Snow levels will likely not be as low with the exception of occasional lower level snow showers or snow pellet falls, due to the convective nature of the cells that form. So over the coming days there will be very active periods over the Sierra and Great Basin especially the Northern and Central Sierra eastward. Although none in the forecast, Great Basin funnel clouds can occur during some of the more active afternoons this upcoming week.
Beyond Mid Week:
GFS days 8 and 11 means, move the block westward over Alaska with the results of rising heights over CA. By the Memorial Day weekend the trend’s would suggest more of a diffluent upper flow pattern which is both warmer over California but still offers the chance of some at least widely scattered or isolated Thunderstorm’s. Mule Day temps would climb into the seasonably low 80s that weekend. A mid latitude ridge is suggested over the Rockies in the GFS by the 25th with still some difluence suggesting some isolated late Afternoon Thunder.
However… The ECMWF (Euro) wants to keep the pattern cooler than normal and unsettled through Friday next week. Furthermore……Cooler than normal temps will continue through the holiday, Precipitation will end by Friday night and so Saturday and Sunday for the holiday weekend look fair but some 6 degrees cooler then normal. (Mid 70s)
What the ECMWF does in the their 5 day means next weekend is to Morph the block over the NW territories’ into a full latitude ridge at 140 west by Memorial Weekend with a negative height anomaly over Los Angelus. In that the upper jet is progged N/S off the coast….Some periods of north wind becoming westerly early that following week is possible. High temps are currently progged to be about 6 degrees below normal for the bishop area, or in the “mid 70s” VS the GFS which is more low 80s. The ECMWF indicates a dry pattern for the Owens Valley Saturday and Sunday and into the next week with a warming trend…..
Dr Howard and the Dweebs…………………..:-)
Massive convection boiling north of the equator Wednesday with strong moist STJ tapping the moisture……Arcing across the Big Island of Hawaii then eastward into Extreme Southern CA/Northern Baja. SSTA’s now more then +1C in the Nino 3.4 and warmer east to well over 2C in the Nino 1+2 region. I am sure that the Anchovies are having a difficult time now down under…..
San Diego has receive between 2 and 3 inches of rain in the last 36 hours. .15 is Climo for the month of May.
If it Walks like a like a duck….Quacks like a duck…..But oh how I know……The key is to wait a few more months so not to step on the duck….. 😉
Although the right combination of dynamics did not all come together for Southern Mono County yesterday, Mammoth Mt did manage to pick up about 5 inches of new snow. A few more inches could fall today as well. The brunt of the storm is focused upon Southern Ca and especially San Diego where up to 2 inches of rain has fallen in some areas and more currently occurring….. Deformation zone set up yesterday was too far to the north of Mammoth, more over Northern CA and NW Nevada. The upper low at 7:00am this morning was located near Dayton, NV tracking east. Precipitation is actually moving south along the eastern slopes of the sierra over Alpine County and near Reno and some of that will wrap back into Mono County before too long….
We have two more systems to deal with. Both are warmer than each other, but possibly better from the possibility of Thunderstorms…..
High temps will remain cooler than normal through the weekend with below freezing lows in the morning…
Blocking Pattern over Northwest Canada will suppress Upper Jet well South into CA this week and into the next…Expect cooler than normal temps with periods of Rain and Snow in the High County…
Tuesday May 12, 2015
Posted at 8:50 am by Howard
Wednesday AM Update:
It appears that we have 3 significant short waves (Storms) to expect weather from.
1. The 14th and 15th. Cold Spring system with subtropical tap. A foot+ possible over Mammoth Mtn (4 to 7) inches at 8K….. (2 to 4 inches above 6500)
2. The 17th through the 19th ( Not as cold as Thursdays system) Snow level above 7.5K to 8K
3. *Possibly the 21st and 22nd; then outlook into the end of the month.
Interestingly….the polar jet actually couples with the subtropical jet with these systems giving them more boost…
Observation…..look at the **16K IR Satellite. You can actually see the results of El Nino in the “Massively Strong Convection” north of the equator over the Nino Basin. This is acting to spin up the subtropical jet and depress the Hadley Cell to the south to 130W/20N as the jet curves over and past the Big Island of Hawaii. So we are already seeing the incipient results from an increasingly warm Nino Basin over the Subtropical Eastern Pacific.
*Note: The NW Canadian Block will be breaking down during the end of the 3rd week of May with the anomalous 500MB heights lowering in that area. This should allow the upper jet to lift back to the north with the majority of anomalous precipitation shifting into the Northern Great Basin, Northward. Warmer and drier weather should be the result over the central sierra, except for some isolated thunderstorms the last week of May.
The new updated PDO for the month of April is out. It shows the strong positive record-breaking teleconnection that has been grossly responsible for this years drought is weakening rapidly…..The updated AMO is still negative which is a good thing.
Dr Howard and the Dweebs…………………………….:-)
I guess if you do not get it in the Winter…sometime you get it in the Spring! Global model teleconnection’s show the positive phase of the PNA teleconnection strengthening over the next week with a notable block over the NW Territories’ of Canada. This effectively splits the upper jet and forces the majority of pacific energy southeast from the GOA where it carves out a long wave Trof along the west coast. This is expected to bring the Central Sierra above normal precipitation over the next week to ten days along with below normal temps. More snowfall is expected with the snow level lowering to 6500 to 7000 at times. It would not surprise the Dweebs if another 6 to 12 inches fell over the crest by the end of this weekend. Some 3 to 6 inches is possible in town mainly Thursday AM through Friday AM and lingering into Friday.
Because of the time of the year snowfall impacts to local roads are usually short lived. However, if you are planning travel over Tioga and Sonora passes Thursday and Friday, travelers should pay close attention for the possibility of temporary road closures.
The upper pattern over the Eastern Pacific and CA remain unchanged with a series of short waves impacting the Sierra with periods of precipitation. More snowfall is expected next week in the high country. Amounts will very with each storm as zones of deformation set up in varies areas being the main focus of occasionally moderate to at times, heavy precip. This time of the year, you not only get dynamic lift from the upper jet but additionally, strong convection from the combination of deformation and surface heating…. This can lead to larger hail and even funnel clouds in extreme cases.
EL Nino: It is already there!
SOI is now crashing as a cold wave takes over Australia the next 72 hours…. Expect the SOI to come in quite negative for the Month of May when the figures are released next June. This is another indicator that this ENSO event has Legs. Watch for more westerly wind bursts over the Central Pacific.
Read how El Nino Effects our weather on the west coast. : http://28storms.com/longrange/how-enso-impacts-the-northern-hemisphere-pattern/
“Prind Point for the Effects of El Nino to the Eastern Pacific”
During an El Nino, there is more rising air in the equatorial Pacific due to the relaxed trade winds. This increased ascent helps raise the equatorial tropopause height. In turn, there is increased divergence at the tropopause and thus the air has to “more quickly flow poleward” to balance the heat.
Since the air is moving at a greater velocity, the Coriolis effect is correspondingly greater, so the air is turned to the east at a lower latitude than normal. The result is an anomalously equatorward-displaced *Hadley Cell. This forces an unusually low tropopause height over the subtropics. Since the tropopause naturally declines in altitude closer to the poles, any change in its height will have more noticeable impact on the 500mb geopotential height. So in an El Nino , 500mb geopotential heights tend to be lower than average “over the subtropics”.
Series of Cold Lows to bring chilly temps and Snowfall to the high country…..Thursday….Tuesday the 12th and possibly Friday later next week….
Wednesday May 6, 2015
Posted at 3:24 pm by Howard
Friday AM Update:
The Dweebs have been traveling the past week, but have been keeping tabs on MammothWeather. A good foot has fallen at the Main Lodge and some 6 to 8 inches in town. Many of the loader drivers have long since removed their chains from their machines and so it may have been a while for the streets and drive ways to be cleared….However, the sun will do rest of the job soon!
It is interesting to note that some scientists called for a wet spring because of the California Nino (not to be confused of an actual El Nino) for this season. I suspect that more will be on the way as the global models continue the trend of an active pattern over California well into the following weekend. The timing still seems to be Monday or Tuesday of next week and/or about the following Friday for another upper low capable of producing more rain or snowfall in the Mono Sierra.
If it walks like a duck and quacks like a duck, is it really a duck? The Models that forecast El Nino are not all that reliable at this time. So….. More time is still needed seasonally to know with a greater confidence as both the ONI and NOI have not signaled strong enough that a Significant El Nino is going to take place next winter. I will say that the Nino Basin is very warm for this time of the year and I suspect growing even warmer by the day.
The prospects for a strong El Nino are very important to the Eastern Sierra for many reasons. For one, the prospects for a deep snowpack and filling local reservoirs of water is most important. And although even a Super Nino most likely will not undue the damage of 4 years of drought, it will pose a sizable dent.
For the Mammoth’s Real Estate industry, it will do much to restore to both buyer and seller, the confidence that one of our most important assets economically…..Resort Real Estate is a viable asset.
Looks like were back into quite the active pattern again with a series of closed lows dropping down over the state or just off shore. Either way it looks active with snowfall, showers and or thunder, on and off for the next week or more.
Timing of the 1st storm is tomorrow Thursday and into that night where a closed low will ride just to the west of the crest then shift east over the Southern Sierra. The high country may get 6 to 8 inches from that system above 8000 feet and 9 to 12 inches over the crest. Another low looks to bring precip early next week and yet another the following Friday….
The Dweebs will have a complete update Tuesday or sooner if there is time…