Archive for January, 2016

Ridge in the west….Cold Trof in the East to give two more nice days before weather turns unsettled again by Wednesday…..Then thereafter for another week….

If you saw the Minnesota game Sunday then you know that there was a Cold Air invasion from Canada over the weekend. The Cold has advanced SE and is part of a slowly progressive long wave trof over the Eastern US. Chances are good that if this was not a strong El Nino Winter,  that this cold trof would have gained a foot hold over the Eastern CONUS and it would have been Ridge City over the west for 3 weeks or so…..  However, the southern stream is already coming to the rescue as it is working hard to carry the meridial flow and its cold air out off the east coast by Tuesday night.    Thus the current shortened wave length will become elongated and negative tilt, as the cold air get flushed out over the Atlantic.  At the same time, the storm door will open over the far west as a series of light to moderate precipitation producers move through the west coast.  Moderate precipitation snowfall wise is between 6 and 18 inches here in Mammoth, over a 24 hour period….  As with any pattern change, the timing of the short wave will be an issue this far out. At least until both the ECMWF and the GFS come into better agreement…  At the Moment, they both agree on the timing of the Wednesday through Thursday short waves and precipitation amounts.   It is the Friday through the weekend holiday that some fine-tuning will be needed…..

 

Although there will be a pattern change, more important changes are coming into the picture in the form of teleconnections.  Its the AO….It is flipping back to positive according to the European model by the 20th…and eventually strongly positive may I add. So this means that the flow will become more progressive as lower pressure develops over the Arctic. This sends the east back into a pattern of above normal temps over time and the storm track a bit further north again. Northern CA and the pacific NW are more apt to get more rain again during week 2. Pretty unusual for a Strong El Nino!  I noticed that a strong Potential “AR’ event may develop after the MLK holiday next week for Northern Ca and Oregon.  This should at the least get us out of the colder than normal temps in Mammoth with higher heights and so we can get rid of some of the ice dams on the roofs…  However with that all said, we need more snow as the sierra snow pack is again below normal. Today we are more than 70% below at this time…

Cold Trof developing over the east will set up over the next 5 to 7 days forcing the West Coast Ridge to build as well….Expect small systems to bring mainly light amounts of snowfall through next Friday…….

Friday the 8th:

Current conditions…Light snow showers..

Weak impulses from the back side of the storm that moved through Thursday Am will produce unstable air and some snow showers today. Little if any accumulation is expected today.

Highs today in the 20s…. Lows tonight in the teens….

There is another small system coming in late tonight and into Saturday Am. We may pick up a couple of inches by Midnight today with a few more inches Saturday AM….

It looks dry Friday with partly cloudy skies and a few flurries…

 

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Its nice during the winter to get a break  in the action for a while. That is what is expected for about a week here in the high country.  With that said, we will still have periods of snowfall but the weather systems will be weak.

Looking at the latest guidance this morning the models are continuing the trend in strengthening the negative phase of the AO. This will be good for the east in  getting snowfall during the next 7 days.  Over the far west and California, I am seeing the development of an amplified west coast ridge, ridged up into Western Canada. Again…The ridge is forecasted to be highly amplified but narrow. This is not the kind of ridge we have seen the past few years that blocked storms for week’s and months on end as we have the strong El Nino related southern stream….   The ridge will have several effects. 1. It will weaken incoming pacific storms for the next 7 days. 2. It will allow temperature’s to warm in the upper elevations. At 8000 feet, daytime highs will climb to the 40s by Mid Week. This many be our *January thaw!

The Dweebs expect periods of light snowfall. There is a system that will bring about 1 to 3 inches in town Saturday and 3 to 6 inches on Mammoth Mt. Another weak system Monday afternoon into Tuesday AM; 1 to 3 inches. And yet another system the Following Wednesday night and Thursday. That one may be light to possibly moderate.

By Friday the East Coast Trof is forecasted to begin to be pulled out into the North Atlantic by the Strong Southern Stream. This is yet another pattern change and we’ll have to wait to see what happens next.  Chances are that we will have some light snow over the holiday, bit it is too soon to say that we’ll have a significant storm.  The Dweebs should have a better handle on the MLK weekend by next Tuesday….

*Next week is a good time for locals to remove or have snow build up removed from their roofs along with Ice Dams. If you have the time, and your Eves are easily and (((“safely accessible”))), after removing the snow, try pots of hot water to break up the dams after icicle’s have been removed….You will need some help, however, it’s worth the time…. Again, this is a very-very dangerous task, so only attempt if you know what you are doing….  Better to have professional’s do it for you….  Ice dams are the number one causes of roof leaks from winter snow buildup.

Another 12 to 18 inches has fallen the past 24 hours on Mammoth Mt bringing Snow Totals over the crest to around 4 feet…..Although no major storms on the horizon….There will be additional snowfall into next week….Some very interesting development’s coming up in the long range…..

Another good snowfall over the past 24 hours in Mammoth with approximately 12 to 18 inches of new over Mammoth Mt and some 4 to 8 inches in town. These were not the totals we expected, as much of the storms energy remained off the coast then inland over Southern California, El Nino Style…..

Once again we are seeing a change in the pattern as the eastern half of the CONUS gets cold Trofing….  This will take the energy out of the big storms, as the west coast temporarily experiences height rises (Higher pressure aloft) with the tendency for weaker storms next week….  However, with this said, we will get more snowfall…

Currently the upper cold trof that is exiting the region will keep our air mass unsettled today lending the chance for more snow showers.  A couple of inches of snowfall is certainly possible. The next system that is headed our way will move in just after midnight Friday night and bring light to moderate amounts to our resort Saturday/Ngt. Expect around 3 to 7 inches in town and 7 to 12 inches over Mammoth Mt Saturday through Saturday Night.

By Sunday the Eastern CONUS trof will deepen and the wave length will shorten leading to sharp ridging near the west coast.  This will make forecasting tricky as it is possible that systems will either punch through the ridge weakening as they do bringing light showery snowfall. Another possibility is that a short wave comes through the ridge to the north of us, then rapidly diverges to the south….spinning up as a closed low over the top of us as it heads south toward SO-Cal. Either way…these are not the type of systems that are big snow producers…..They bring mainly cold-showery light snowfall.

OUTLOOK: (Long Range)

This is not a forecast but just something to keep in you back pocket…..  Most of the Inter-seasonal models are giving us a nice break over the Martin Luther King holiday weekend.  This is in the week 2 period….   What I want to blog about is the possibility of another storm cycle around that time frame….or just beyond

 

Here are some thoughts.

  1. We have a strong -AO at the moment that is expect to remain for the next 2 weeks at least.  The PNA is positive.  (If you want to know what these teleconnections mean, I have already addressed them in recent discussion’s…
  2. Due to the Eastern CONUS trof in development,  a narrow but highly amplified ridge will develop along the west coast over the next 5 days….This ridge is not the type of ridge that is likely to block the tremendous energy of the southern stream that is barreling across the pacific due to El Nino. There is the possibility of a bust in the Dam (ridge) later next week with a resulting break through of the westerlies. The fact that NCPB ( Bias-Corrected Ensemble Global Forecast System) for the  “MJO” is in *phase spaces 7 and 8 and rotating within that area means that there is a tremendous amount of convection and constructive interference going on with the ENSO base state. The location is near the dateline and east north of the equator. The SOI is still tanked negative, so something has to give….  I know that some forecasters are saying that the GFS is out to lunch and the MJO is really progressive, but the GFS has been touting it for several days now and again today.   Look out for the “possibility of a bust in the Dam (break through in the westerlies) late next week or just past in the week beyond….  Again…..this is not a forecast just some interesting curiosities…

* http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpb.shtml

Dr Howard and the Dweebs……………………….:-)