Forecast Models Still Struggling with Split flow over or just west of California…Trend of late is for storms to be more consolidated as they come in with SSW flow offering high end moderate precipitation totals….. A winter Weather Advisory has been issued for Mono County beginning at 10:00AM Saturday….to 10AM Sunday…

Updated Saturday AM 5:00AM:

Officially our forecast area is under a winter weather advisory for Saturday at 10:00AM through Sunday 10:00AM. However, the models did come in a bit wetter this afternoon. So in order to keep from yo-yoing the winter weather advisory will remain, Nevertheless, I believe that it is quite possible to reach winter storm criteria within this time frame here in the Town of Mammoth near the Village (12 inches).

Mammoth Mt by Sunday noon, there could be up to two feet over the crest.. The Sunday afternoon into Monday morning storm is more focused to our north. However, it is highlighted by the dreaded NW upper jet. So it will be especially windy. Surprisingly, the WFO forecast is for another 6 to 10 inches of snow Sunday night for Mammoth MT and some 3 to 7 inches in town. Local Blizzard conditions may result from the wind storm expected Sunday night….

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Winter Storm Watch has been downgraded to Winter Weather Advisory. However, Mammoth Mt still expecting the upper end of Moderate amounts as the criteria is 6 to 18 inches in a 24 hour period.

It will be unsettled Sunday and Sunday night with wind….Snow or Snow Showers and colder temps. Expect Gradual Improving conditions later Monday afternoon into Tuesday Morning. A new wetter storm moves in Tuesday night into Thursday.

12:45pm Update RE: EURO MODEL….European Model is onboard now with GFS model for the mid week system with more consolidated upper flow, making it another strong Moderate to possibly Heavy snow producer for Wednesday and Thursday next week….

From Thursday AM; A series of Storms is headed for the high county beginning this weekend. The initial storm will he highlighted by two distant areas of lift. The first one will lift the warm sector with a cold front Saturday with the heaviest precipitation rates expected Saturday afternoon into the early evening hours. The second portion riding into the cold air will be more showery in nature with lighter snowfall accumulation’s expected Sunday…. The combination of the two storms is expected to bring between 1 to 2 feet of snowfall to Mammoth Mt by Monday AM. The Town of Mammoth will see all snowfall from beginning to end as the freezing level will begin about 7,000.
Thus the snow level will start at or below 6000 feet. Around a foot of snow is expected Saturday into Sunday for the town. There is likley to be travel restriction’s along highway 395 Saturday and Saturday night. Strong gusty winds with periods of heavy snowfall will make travel hazardous. All vehicle’s should at least carry chains for the trans-sierra portion of highway 395 this weekend.

The outlook for next week continues to improve for the prospects of significant additional snowfall. The New 12Z Thursday GFS model, has the following mid week system coming in much more consolidated now, similar to this Saturday’s storm. Although as of this post, the Dweebs have not seen the new European’s, Thursday 12Z run to compare with. This morning’s 12Z GFS is very encouraging as it has a wetter scenario due to a deeper fetch from the southwest and a cyclonically curved upper jet. This mid week storm was expected to split with weaker results due to the splitting process. The more consolidated scenario is capable of delivering several feet of snowfall if it is correct.

The Dweebs will keep all of you updated on these changing weather forecasts over the next week….

Dr Howard and the Dweebs…………………:-)

Another Cold Shot of Energy dropping South through the Great Basin with Snow Showers Monday then Moderating Temperatures into the first week of the New Year…..There are an increasing number of ensemble members of most global models touting the return of an Active Pattern by next weekend…..However, this is a pattern with a lot of splitting going on…..

January 1st, 2019

Days will be milder beginning Wednesday with seasonal temps for Thursday and Friday….There will be a return of the 40s for highs Thursday and Friday. Lows near zero of late, will rise to the 20s….lighter winds aloft will be highlighted.

Upcoming pattern shows promise to bring significant snowfall beginning this weekend. However, there will definitely be a split in the upper flow that will give forecasters problems. There looks to be a storm or two in the bunch at will give the Sierra plentiful snowfall, however, others that seem headed in our direction that will dive down the coast and miss us completely. Looks like a head banger pattern to me….

The Dweeber….


12-31-2018 Update
Happy New Year From the Dweebs!!! Latest gfs and ecmwf global model runs show a number of systems next week, bringing either moderate snowfall to possible heavy snowfall for a time. The Euro (ecmwf) has a small atmospheric river tied to a system on the 7th.

These are just forward looking systems that have little confidence to forecasters at this time. If the trend holds through this Wednesday or Thursday, that would be very encouraging… The guidance suggests 1 to 3 feet of snow next week, just from this mornings 12z runs. That is not a forecast…

12-30-2018 As headlined….Another Cold Slider drops south Sunday night into Monday night bringing with it a short but chilly period to the Eastern Sierra Monday and New Years Day. Thereafter. a milder period will develop with light breezes by Mid-Week with more seasonal temperature’s Wednesday through Friday.

The Dweebs this morning can not ignore the odds of the return of an active pattern for the following weekend. However, the devil as they say, is in the details. This week, the MJO fly’s rapidly through phase 6 into 7 and Phase space 7 shows better odds of being wet in parts of California. It still favors Southern CA the most, but the CFS shows in this instance, wet for most of the state week 2. We will hopefully know more by Mid Week.

FYI, next weekend is the end of week one and the following week being week 2. Week 2 may prove to be a zinger! 😉

Sensible Weather:

Expect highs in the upper 40s today Sunday, followed by mid 20s on Monday with light snow showers Monday. Expect another round of cold NE wind on Mammoth Mt with strong wind chill’s Monday. New Years morning will likely be in the single digits with highs in the low 30s….There is a warm up Wednesday into Thursday. Thursday’s high temperature will warm back into the upper 40s. The pattern expected the following weekend will involve milder pacific air. However, if by chance the initial system comes in over cold air left behind over the Owens Valley with no surface wind, there could be some snow for the Owens Valley floor. The Dweebs hope to know more by Mid Week. PS. The Euro favors the more southerly track while the GFS has more of a track further north. Time will tell…. Of note, transitionary pattern forecasts are less reliable…

Cold Inside Slider pattern will bring snow showers and cold temperatures to the high country…Gusty Winds over the higher elevations prompts the awareness of a Wind Chill-Factor….. Temperatures to moderate over the weekend….No Major Storms in sight….

12/29/2018 10:00AM

Thoughts about the long range….

When ever I see a possible series of storms during any month of Winter in the week 2 period, IE in this case, between January 5th and the 11th, I always look to see where and how strong the MJO is. The MJO has a statistical relationship to the longer range for weeks 1 through 4. In this case the week one period falls within the MJO phase space 5 and 6 and for January, this tend to be a drier than normal period through early in the phase space 6 with heights increasing along the west coast; See: http://www.americanwx.com/raleighwx/MJO/MJO/JanuaryPhase6gt1500mb.gif

So the current Saturday 12Z run has some support for the weekend storm of the 5th of January late Phase 6). However, the ECMWF Shows a weakening MJO as it moves into this western pacific region with an increase in heights in the +PNA. It delays the storm into the week 2 period. Prind point here is that using only the GFS, the weekend storm of the 5th is a somewhat low confidence bet at this point. Going from phase 6 to phase 7 has a better relationship to storminess for CA and that comes during the week 2 period. This time of the year, the week 2 period storm track may favor Southern CA best, especially early during week 2 then further north later in week 2. SEE: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/LaggedComposites/whmjo6.djf.z200composite.web.png

12/28/2018

Mammoth Weather.com picked up 3 inches of snow over night. Skies are clearing….it is cold with highs near 20 today. There is a wind chill factor on Mammoth Mt today….ware face protection….:-)

As Forecasted…A a cold inside slider is bringing snow showers and cold temperatures to our region. Temperatures are running some 20 degrees below normal for this time of the year which should be in the low 40s. Both Thursday and Friday nights lows will likley be below zero over much of Mammoth. As the upper flow becomes more NE/SE orientated today, upslope snow showers are likley with light accumulations expected. 1-3 inches. Friday will be the coldest day with highs near 20 degrees.

The Weekend outlook shows moderating temperatures that become seasonal by Sunday. Wind protected colder valleys along highway 395 are likley to experience over night lows around -10 to -15 or colder.

The longer range….First week of January is being forced by a strengthening MJO entering the Western Pacific. With the MJO in phase 6, it is likely to suppress storms and precipitation over California through the first week of January. SEE MJO Phase 6 composites for California (jan): http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/Composites/Precipitation/DJF/combined_image.png

This MJO is an area along the equator highlighted by a pulse of rain and thunderstorms. It is currently over the far Maritime Continent moving westward to the western pacific. Strong westerly wind bursts are now occurring over the Eastern Indian Ocean. See: http://www.bom.gov.au/climate/mjo/#tabs=Time-longitude In that the American GFS model and their ensembles really amplify this MJO feature to the point of +4 deviations of normal, it will be very interesting to note things like latent strong westerly wind bursts that develops in response, that possibly intensifies El Nino on a climate scale of time. However, on a shorter time scale, if the Climate Forecast system, (CFS) is correct, noting and contrary that the GFS and ECMWF appears to be much quicker and less amped, it is possible to have a strong atmospheric response on the central west coast in the form of an “AR”, sometime depending upon the speed of the MJO, during the week 3 period of January. The composites relate to warmer than normal temps for California phases 7 and 8 with a bias for precipitation in phase 7 followed by drier than normal in phase 8 then wet again phase 1. The classic MJO induced AR’s usually occur when the strong MJO crosses from Phase 8 to phase 1. The pattern can be forced by Rossby Wave Dispersion into the Pacific Basin with fast Meridional flow aloft, followed by retrogression of the long wave features over the Eastern Pacific. An extension of the East Asian Jet to the west coast is then possible. The process includes undercutting the EP ridge forcing -EPO, that transits to -WPO. it is a wait and see if the ECWMF and GFS follows suite. This of course is always a long shot, however possible…

Sensible Weather: Watch to see if: 1. we have a dry week during first week of January; followed by a possible storm during the second week of January, followed by a strong amplifying ridge in phase 8 with dryer than normal weather, followed by Pineapple express. Timing may change depending upon speed of MJO. Of course, if the current runs of the GFS and ECMWF are correct, then this post is one for the trash can.

Will Watch to see if the ECMWF and GFS falls in step with the NCFS keeping the MJO very strong and propagating it through phase spaces 7, 8 then possibly 1. The fact that the ENSO basin has not fired up convectively yet is a good sign in this respect.

Dr Howard and the Dweebs……….:-)