Archive for October, 2015
Low pressure system approaching west coast will weaken and sheer as it moves through Wednesday and Thursday….light amounts of snowfall will occur over higher elevations Wednesday/Ngt ……..Much colder system may dig south over the Sierra this coming Monday….
Monday October 26, 2015
Posted at 5:33 pm by Howard
Brief update Monday AM: Full Update Later today….
- California Rivers center shows about 2.00 of QPF slated for our own Sierrra crest by Monday night. the break down is an inch of qpf between 4:00am Monday and 10:00am so that will be the heaviest period.
- .55 from 10:00am to 4.00pm It will be all snow near the village soon…
- Another .50 between this evening and Tuesday PM…
Overall this is a 6 to 12 inch storm for the town and 1 to 2 feet for Mammoth Mt
5:00PM Wednesday Update:
This is a quick update for the QPF for the cold storm Sunday night through Wednesday.
Steady Snowfall to begin Sunday night and will end mid Monday morning. Snow showers will continue through the day Monday. Snowfall will increase again Monday night, then if Euro model is correct, snow showery Tuesday through Wednesday night with light accumulation’s. Few lingering showers possible Thursday. Dry Friday through Saturday next week.
QPF snowfall totals via the European model will range from 12 to 18 inches over the upper elevations at and above 9K. Roughly 1/2 of that at the Village and half again of that 1/2 , at Highway 395 east of Mammoth. The storm is 4 to 5 days away and so amounts are subject to change.
Snow levels will fall to the Mono County Valley floors by Tuesday.. Highs in town Tuesday in the 30s with teens and 20s on Mammoth Mt.
Fabulous snow making conditions Monday through Thursday if the EURO is correct as the upper low lingers into Thursday…to the contrary, the GFS is more progressive.
As of late…those that are following the MJO know that there is a lot of amplification in the RIMM over the Western Indian Ocean. According to the CPC, they think that it is being supported by a Kelvin Wave traveling east through that area. They feel that it is highly unlikely that the MJO signal will remain strong or move as far east to the Maritime Continent.The El Nino base state has very strong upper subsidence over that large region north of Australia that makes up the Maritime Continent. However…..Just an FYI for the west coast of the CONUS. A strong MJO progressing east from south of India, between 70E and 95E may flip the PNA to negative over the eastern pacific. Additionally…looking at the MJO composites, in November, if a strong signal goes from Phase 1 then 2 to phase 3…the odds are pretty high for the PNA flip and thus cold wet weather for CA. Maybe this is what the new deterministic ECMWF is looking at…. (See Below)
Outlook for next week….
The new October 27th, 12Z Euro really dumps the cold air in here with 700MB temps dropping to -8C by Tuesday morning. This system is from the Gulf of AK….Taps a lot of cold air from AK and BC, Can. Then drops pretty much SSE over the top of us. There is some over water trajectory, but the main dynamics will be in the cold core low as it moves over the top of us.. QPF is suggestive of up to a foot this far out over the higher terrain but this system is cold enough to bring snowfall to most of Mono County above 6,000 ft. early next week. If by chance the storm digs back west a few hundred miles….then were looking at something different….
More later…..Lets light this Candle!
Dr. Howard and the Dweebs……………….:-)
The weather system west of the US has an upper Low pretty much anchored in the Gulf of AK. The upper trof pivots negative tilt and sheers southeast into CA Wednesday. It is picking up quite a bit of subtropical moisture at this time. The guidance is in agreement in weakening the upper dynamics as it moves into California Wednesday. In the meantime, lots of mid and high level moisture from the remains of Olaf will move over California Tuesday into Early Wednesday. The Dweebs take, on the QPF will be a blend of the GFS and ECMWF. Amount look to be about .25 to as high as .50 over the upper elevations. The snow level will be pretty high, generally above 8500 feet. Cooler air following the trof will allow the freezing level to come down a little Thursday, after most of the precip is gone.
The high country will have it first real taste of cold weather with a cold digging Sierra Slider early next week. So far this next system is progged to have an over land trajectory. Thus, it should not be a major precip producer. But it looks to be mostly snow in the Town of Mammoth Monday and Tuesday. This is actually a good storm to get the snow making going on Mammoth Mt as temps at 700MB are currently progging between -6 and -7C, or around 20F degrees. The Dweebs will have a better idea on snowfall amounts Thursday or Friday…. Light to possibly moderate amounts are in the cards….
Dr Howard and the Dweebs……………………..:-)
Storm Clouds Clear Out to leave cool crisp morning in Mammoth with Icy Conditions and Clear Skies…..Westerlies continue to slowly strengthen as well as El Nino…..The week ahead looks seasonal and dry….However….Toward the end of next week, Stormy….
Monday October 19, 2015
Posted at 8:43 am by Howard
Chatted with one of the Leed’s this morning and the upshot was that too much is going on at this time to make an accrete QPF forecast for the Wednesday night-Friday system. There are two tropical storms out over the pacific. One that is phasing with the westerlies over the western pacific, but that should be well into the guidance by tomorrow AM. Over the eastern pacific, tropical storm Olaf is being picked up by the next wave approaching the west coast.
I will make a guess at this point but there is not a great amount of confidence. Maybe by tomorrow morning things will be different?
For what ever it worth, it appears that chances are decent that some light snow to fall…..between Wednesday afternoon through Friday night. The snow level will begin about 8000 to 8500 feet Wednesday night but will come down Thursday and down further Friday/Ngt. The wettest model tries to bring in close to an “inch of QPF” over the west side of the sierra, over the 3 day period Wednesday night through Friday night. The driest model brings in about .25 during the same period. That is quite a big spread but that is what I am working with. October is a tough month for forecasting….It should be easier later in November though the Winter. Next update in the morning…
Longer range is not convincing enough to get excited about anything yet…..However, hemisphere is chilling fast and so it is just a matter of a few weeks to start seeing in the models some significant storms headed for the west coast….
OCTOBER 24th Update:
Models are diverging from earlier prongs for a storm capable of delivering several inches of snowfall to the eastern sierra. I still expect some light snowfall Wednesday over the higher terrain but it is not looking as favorable now as 3 days ago.
I will have a complete update Sunday on next weeks weather and beyond…
Oct 21st, Wednesday AM:
There appears this morning, to be the possibility of a decent storm, sometime between next Wednesday and Halloween.
Here are the ingredients:
- Typhoon Champi was located some 500Mi due south of Tokyo this morning
A. Over the next 5 days Champi will be totally extra tropical and merging with the westerlies as it moves NE
- A moderate trough will move off the Asian coast this Saturday AM and constructively phase with Champi over the following 24 hours building a strong ridge down stream on a longitude between the Dateline and the Hawaiian Islands.
- That amplified ridge deepens a new trof down stream over the East Pac tapping cold from the GOAK.
- This eastern pacific trof entrains now Hurricane OLAF as a extra tropical storm which spins up the jet in the negative tilt system. This builds an upper ridge over the pacific NW while the upper trof digs into California “”About”” next Thursday the 29th. This timing is subject to the scenario over the western pacific.
- Climo wise, this will bring the possibility of our All Hallows eve storm, even through the storm may come a day or two sooner. The models also suggest that the leading trof may be just the 1st in a series into that following 1st week of November.
Wednesday PM Update:
It should be noted that in advance of the system next week, there is a mid latitude upper low north of Hawaii this afternoon that will bring clouds and possibly some showers this Sunday….
Once again another interesting 5 day period of weather over the southern half of the state of CA. Precipitation amounts ranged mostly between 1.25 to 2.00 inches in the sierra with some isolated amounts of 3.00+ inches, especially in the mountains north of Santa Barbara. The weather has been greatly influenced by the highly anomalous sea surface temps off the Southern California Coast this Summer, and now Fall. The positive phase indices of the PDO for the month of September reached 1.95. Comparing that to September of 1997 was 2.19. A moderate weakening began in October of 97, before rapid weakening the end of that year. The PDO in its positive phase is responsible for a lot of heat in the oceans along the west coast the past 12+ months. Oceanic Kelvin Waves have added to that heat this year allowing SSTA to reach record levels west of Southern CA beaches. Sea Surface temps according to buoys, recorded temps just over 80F is some cases this past September.
The Quite Giant:
El Nino’s effect upon our current weather is quite incipient now compared to what is likely to happen this Winter as the East Asian Upper jet strengthens and migrates south and splits eastward from the Subtropics. Its split southern branch associated with the +PNA teleconnection pattern will likely bring a lot of beneficial rains to the Southern half of our state. In the case of strong El Niño’s like this one, even the more northerly portions of the state that are often times absent from the effects of El Nino’s wet pattern may benefit.
The Dweebs are following the RIMM phase space that are at least suggestive of a strong MJO to develop over the Indian Ocean with the potential to flip the PNA to negative in the coming weeks. . As mentioned in my last discussion, there appear to be an emerging signal over the east coast of Africa in the Eastern Indian Ocean. As of late, the Ensemble Global Forecast System may be hinting at an Equatorial Rossby Wave or tropical Storm or KV because of the emergence is followed by an Eastward shift with the convection. That is not all that encouraging….
The ECMF is progressive and needs to be followed…..As strong Convection between 70E and 100E over the Indian Ocean is often associated with a flip in the PNA to negative and long wave trofing over the Eastern pacific. This looks like sometime between week 2 and 3. I will update Wednesday AM after the CPC update….
As mentioned last August, the warm water along the west coast is reminiscent of the winter of 1957-58 El Nino year. However, the strength of El Nino this year is stronger, but the SSTA structure along the west coast is similar. That allowed a winter of 140% of normal to Mammoth Lakes. With as much energy (Heat) that is trapped in the tropical oceans over the EQ eastern pacific, there is likely going to be some pretty intense precip events this winter. The CFS VS2 is calling for a November that has normal amounts of precipitation for Mammoth Lakes. December on through the Winter is expected to be much wetter than normal. I have given up on following the ECMWF monthly guidance for precipitation as it preformed so poorly last winter and several winters back. To me it does not make much sense to try to predict 3 months of precipitation on a monthly basis, let alone a month’s worth of precip for area’s like Mammoth Mt, when you have to consistently update those figures during the month. The best forecasts will be the ones with the best guidance 7 to possibly as much 10 days out, once we get into the meat of the winter.
Although, this winter looks quite wet snowfall wise with snow to ratios low, and the likelihood of the Platinum Powder Criteria not being reached until late winter like late February or March. Nevertheless the Dweebs will still hope for a good cold one at some point! In the meantime, for those that have signed up for the Platinum Powder alert system, I will make good use of email by offering you all some very good forecast information well before the weekends, so you can plan accordingly before coming to Mammoth. In addition, if the Dweebs see an opportunity to advise for a Platinum Powder advisory or alert, you will benefit from the timing to cut up some amazing powder…… As a reminder, Platinum Powder criteria is 12 inches or more of light snowfall which for the majority of it is at ratios of 15 inches of snow to one inch of water at 10,000 feet and above….
Dr Howard and the Dweebs……………………..:-)
Record to near record heat will give way to clouds and cooling Wednesday Through the Weekend as Boomerang upper low pays a revisit…
Monday October 12, 2015
Posted at 5:31 pm by Howard
Wednesday PM: 10-14-15
As we wait for the subtropical upper low to move on shore and spread precip north into the Sierra over the next few days….I have taken another look at the CFS vs 2. It looks pretty dry for the rest of the month of OCT. However, some of the long-range ensembles (Week 2) try to bring in a cool trof from the Eastern Pacific into CA. The only comment I will make is that, this time of the year, (October) is the worst month for model accuracy. So they may be saying one thing and doing another. Best to stick with the week at hand for best results. Climo wise, the weather does begin to change that last week of October so we’ll see.
Todays SOI shows tanking at -44! So atmospheric coupling still well underway with EL Nino!
MJO: A strong signal is developing over the Indian Ocean the last week of October. This might be why there is a weather system suggested by the GFS and EC.
However, the guys a CPC are not all that sure of the signal being a MJO.
Read from their latest discussion…
During Week-2, above-average rainfall is likely over the Central Pacific while below average rainfall is likely over Southeast Asia and the Maritime Continent. Both of those forecast regions are linked to the ongoing El Nino.
“Some models are indicating a strengthening MJO anywhere from Africa to the eastern Indian Ocean. Recent observation based analyses indicate a “Kelvin Wave” over the Central Pacific now, and typical propagation speeds would have the Kelvin wave located over the Indian Ocean, so at this time, uncertainty is too high to depict any large-scale, MJO-related impacts to that region”
Note: I will update on the idea of either a MJO or KV Next Tuesday or Wednesday for that following week.
PS, if that emerging signal is a MJO, that would most likely bring a major pattern change to the eastern pacific that last week of October by flipping the PNA to Negative. That would quite possibly mean “SNOW” for Mammoth
Tuesday AM Update:
Today should be the last of record or near record highs as increasing cloud cover Wednesday will keep temps below any past records. From Southern CA inland, to the Central Sierra, Meteorologist’s are keeping an eye on the cut off low that’s been over the west, for close to two weeks now. Latest IR Satellite loops are showing good upper divergence in NE quad. The upper low is expected to move into Southern CA Wednesday night with the location of the center of the low over the Channel Islands at 18Z Thursday morning. It get the boot east into southern NV very late Saturday night….by an upstream Trof. That next upstream trof is being handled differently by both the EC and the GFS with the GFS splitting it and the EC forming a coastal closed low. Thus the ECMWF is the wetter solution with the GFS about half as wet. Will update again Wednesday to see how the models are syncing….
Excitement in the weather about record heat followed by a Boomerang upper low later this week has folks scratching their heads wondering what is going on with the weather? Yes there is an El Nino and the warmer than normal SSTs along the CA coast will supply additional moisture for another unusual weather event beginning Wednesday into the weekend. Snow levels will be very high until they come down enough to dust Mammoth Mt this weekend. The Southern Sierra and even the mountains around the LA basin will get bulk of the precip with some areas like the past subtropical systems dropping over 2 inches of rain over favored terrain. The waters are so warm off Baja and Southern CA that the models are going to underestimate the QPF.
So what is the history of this system: (At least from Memory); those that know more exact timing feel free to comment.
- It began as an upper trough that dropped south from the BC coast October 1st and 2nd as an inside slider inland over Washington and Oregon . It dug back and closed off along the Northern CA coast early that weekend. The track took it all the way SSE to near Paso Robles/Santa Barbara, then ESE across Kern the Mojave desert. Through the process, there were areas of heavy rain and high elevation snow over the Southern Sierra, White Mts and mountains along the CA/NV boarder. The Southern Sierra east to Western NV got the bulk of the precip. However, there were reports of heavy rain showers in the LA area as well.
- The track of the upper center moved as far east as New Mexico before it dropped south over the Sonoran Desert of Mexico before last weekend. As high pressure built into CA from the SW, the upper flow sent the upper low across the Sea of Cortez and off the coast of Baja early last weekend.
- Today the upper low is west of central Baja. Although it may still be considered a cold core low. It has tapped into a lot of tropical moisture to its SW. As the upper high breaks down over the far west, the upper level system will lift into Southern CA Wednesday into Thursday. Although the precipitation guidance shows moderate amounts of precip with this old low, looking at the latest satellite IR, you have to ask yourself if they are underplaying the QPF for later this week. Nevertheless, it looks like primarily a Southern CA, Southern Sierra system east into South West Nevada storm. However, precip will spread well north into the Central Sierra. Amounts will be between .5 to 1.00 in favored mountain areas of Southern Mono County and the White Mts.
Just a quick update for the change in the weather for the end of the month. The CFS v2 still has cooler then normal temps with a long wave trof, south over the Great Basin, This is typically a dry pattern with light precip. The Dweebs will take another look at it next week….
Dr Howard and the Dweebs………………:-)