Although current dry pattern over the far west continues….A few small systems may bring some breeze, cooling and light snow or snow showers early next week and the 11th……

10:15AM Thursday the 3rd.

Yesterday, a system droping south from the mid-west to the Texas Panhandle spread cooling through the desert southwest where it reached the Eastern Sierra over night.   As a result, it was a cooler morning in Bishop CA with a low of 18 degrees and Mammoth with a low of 16.  Today, as the result of that same cooling, it will be about 8 degree cooler with a forecasted high of 50 in Mammoth Lakes.

As mentioned in my discuession below, the west coast ridge is in control. However, with that said, there are at times when there are weaknesses in the ridge that can allow short wave energy to makes its way to various areas. In our case, the weather the end of this week shows just that. Although the models handel a small area of low pressure differently. They both agree to the idea of around .01 to .03 inches of precip as indicated in their quantitative precipitation forecast. (QPF) for as early as Sunday afternoon or as late as the following Monday.  Its a small feature, but one that both the GFS and ECMWF models bring a much cooler thickness pool over head between Sunday night and Monday. As a result, Monday will see highs down into the 40s.

Long Range:

Looking at last nights GFS ensembels 5 day means, the current planetary Rossby Wave Train across the Central and Eastern Pacific eastward to the East Coast shows a strong negitive tilt, negitive height anomaly (Long Wave Trof)  near the Dateline with a positive tilt mean ridge position over the Far Western States and another trof stretched out from the Southern States to the SE. Over the next 7 days, the trof over the central pacific retrogrdes a bit west while the trof over the SE progresses east.  This causes deamplifacation of the pattern over the west, that results in a split flow pattern of which,  results in a trof over Northern Baja. This does not get us where we want to be pattern wise.

Over time, (Week 2) the upper height anomaly over the west, retrogrades off shore to 135W. (mid month)  We are then back in a pattern of NW sliders much like in November. Storms on this track can give us light to moderate snowfall if current guidence varifies. We on the east side of the Sierra normally do not get big storms with heavy precipitation from NW sliders or from lows that spin up and drop south down the west coast.

Inter seasonal:

For whats it worth, the Climate Forecast System (CFS)  Shows Preciptation developing over Norththern CA during the 3rd week of December with that field shifting south into Central CA the last week of this month.  This time frame is out of the relm of the week 1 and week 2 extrended forecasts from the GFS ext and ECMWF.  The MJO forecasts are of no help for signifacant precipitation during that time frame.

 

Stay Tuned…..Keeping one step ahead….:-)

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Our pattern over the far west is about as dry as one could be for December…..The MJO Phase 4 and 5 composites teleconnects to a ridge over the far west. Being that the MJO is forecasted to stall over the Maritime Continent, prospects for the continuation of dryness is indicated for another week, possibly two..   However, even so, there are a few possibilities of some light snowfall.  Both the GFS and the ECMWF to a weaker extent, drops a cut off low south through Northern NV late Sunday night into Monday and another around the 11th of December through inland Northern CA. These are not storms from the west as the active storm track remains well to our north. Rather, small amounts of energy, progged to come through an area of ridge weakness. The track if one would develop would be either the colloquial inside slider, or the California slider that are inland, west of the Sierra Crest from Northern CA. These systems if they do develop, are for the most part, moisture starved and without any pacific moisture tap. However, they do offer the possibility of light amounts of precip. (1-6) inches, if they are positioned favorably.

 

More Later………………:-)

 

Dr Howard and the Dweebs……………..:-)

Reporting and WX Forecasting for
Southern Mono County Weather since 1980.

November to Go Out on a Dry Note with December Looking Much the Same…..La Nina Running the Show….

Its Definetly a Dry Nina this year, with strong convection confined over the tropics over the far western pacific…   The MJO will stall over the phase 5 area Maritime Pacific/Western Pacific and it will be Ridge City “into” the 2nd week of Dec…..There is a system indicated toward the middle of the month. However, little confidence at this time that it will bring much more than light snowfall, wind and cooling….    La Nina continues to intensify over the tropical pacific…

Lagged Composits for Phase 5 in December:

More later………………..

 

Dr Howard and the Dweebs…………………:-)

Storm Total 6 to 9 inches……Upper jet to pull through this weekend with mainly dry weather expected…..MJO moving into Circle of Death….

Saturday 11/21/2020

Series of Northwest sliders will bring periods of breeze, cooling and maybe a few flurries or showers. 1st slider moves through Monday the 23rd, another Thanksgiving and the last in the series on the 30th. That one on the 30th may pinch off a closed low and give us some snow showers. Will update on that later next week to see if there is anything to it.  With Tropical forcing weak, (OLR) and moving east toward the western pacific, we are likely to ridge up and warm up during the first week of December. Next productive major change in the pattern will be in Mid December, as long range teleconnections show once again, the possibility of a (-PNA) teleconnection pattern setting up. Hope it makes it this time.  For whatever it is worth, the long range GFS Super Ensembles show the potential for some cold stormy weather the week before Christmas and the ECMWF Ext. Ensemble shows a stormy period from the middle of December all the way through months end and beyond a few days into the New Year….

 

Think Snow, Stay Healthy….

Dr Howard and the Dweebs……………………..:-)

 

 

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Stardate Nov 20, 2020:

Remnants for last weekends pattern are shifting east now with a weak branch of the westerlies bringing moderate winds over the Crest and light breezes in town. Temperatures began to invert again this morning with colder temps over the lowest elevations of town as compared to the upper elevations. Currently high clouds are streaming through with this weak upper jet branch. A short wave ridge moves in this weekend and will bring clearing skies and colder temperatures to the valleys along with stronger temperatures inversions.  Daytime highs will bump up a bit for Mammoth Saturday and Sunday with high temps pushing into the low 50s. Nights will be in the teens over the lowest elevations of town and high single digits over the colder valleys. However, up into the twenties in the upper elevations of town.  Nighttime snowmaking will be good as our airmass will be dry with NE flow.

The current pattern as it pertains to the East Asian Jet is very unimpressive. The upper jet resides over the Pacific Northwest keeping the windward Olympics wet with decent shadowing for Seattle and precipitation expected south through Oregon with lighter amounts south to Highway 80. Mother Natures definitely has her foot off the gas peddle over the central eastern pacific..

Looking at this mornings ensembles of both the ECMWF and GFS, there members favor the upper jet continuing to the north of us as it approach the Pacific NW coast then drops south as a NW slider into the Northern Great Basin. Over time, the long wave trof shifts east of the Mississippi. This is a dry pattern for the Central and Southern Sierra. However, on the optimistic side, there are a few members of the ECMWF that split off some short wave energy around Thanksgiving and again the very end of the month.  The CFS continues to hang on to the notion of a period of wetness between the 26 and Dec 2nd.  As mentioned yesterday, the vast number of ensembles do not favor any significant storminess through months end or for that matter,  the next two weeks.   However, if one wants to know what the outliner members show, the following was indicated in last nights 00z ECMWF;  It had two splitting systems that spin up closed lows, which one affected mainly Central and the Southern half of CA and the Desert SW.  The first brought colder weather to the Sierra along with light snowfall thanksgiving day then a stronger system that brought moderate snowfall mainly to the Sierra Crest westward. This was indicated in the Monday Night the 30th through Dec 1st. Again, there are just few of these ensemble members and is not reflected in any outlook.  The only glimmer of hope is that the Climate Forecast System (CFS) is still hanging on to the notion of a wet Northern and Central CA between the 26th and the 2nd this morning.  It will be interesting to see if they drop that notion over the next few days.

 

I’ll let you all know!

 

The Dweeber………………:-)

 

 

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Breezy weather continued this morning with windy conditions over the highest elevations w/gusts to 60mph. The Trof that brought us the snowfall Wednesday has sheared east and what’s left is a weaker trof that will gradually move through over the weekend. Looking down the road, there are several short waves that will be impacting regions to our north. The Pacific NW will benifit from these small to medium sized systems south at times to Northern California. Early next week (Monday) there is system that may bring some snow showers and gusty winds to Mammoth.  Temperatures will be fairly seasonal now with breezy periods going through next week. Expect highs in the 40s with lows in the teens this weekend. Travel weather does not look to be impacted at this time.  Great snowmaking weather will continue with cold nights.

Now getting to the point of the longer range and tropical forcing;

The Dweebs have been watching what has been going on over the Indian Ocean with the MJO.  More and More of the Ensembles Members of both the ECMWF and GFS has trended the MJO into the “Circle of Death”. The MJO peaked around 60E to 70E Monday and Tuesday and is now weakening rapidly. Thus the Climate Forecast System was wrong in its forecast of the MJO Remaining strong enough, long enough to flip the PNA to the extent that it would create both a deeper and stronger negative phase PNA pattern over the far west; “this cycle”. This means that it is very unlikely now but not impossible, that a good storm will occur this far south into California through early December. There are a couple of short waves the end of the month that may bring some light snowfall, however, a major storm capable of dumping several feet in Mammoth is not in the cards anytime in the next one to possibly two weeks. The La Nina Base State is very strong and maybe acting as a barrier with its quite cold water, destructively interfering to the MJOS convective envelope. LA NIna continues to strengthen as evidenced by the very strong trades blowing east to west.

So where to we go from here?

For the record, the Climate Forecast System this morning , (CFS) still hangs on to the idea of a stormy period for Central and Northern CA, northward in its forecast this morning for the 26th through the 2nd of December.  So it is still possible we may have a decient system the end of the month according to the CFS.  Its just that the MJO is decaying so rapidly that even most global ensembles models with the outliner of the GFS Super Ensemble, keeps everything to our north. So there maybe something else going on teleconnection wise, that it is seeing, However, with that said, the odds do not support a good storm from The Dweebs vantage point for the end of the month at this time……… If that were to change….we’ll let you know.

 

Dr Howard and the Dweebs……………………………….:-)