Archive for year 2017

Gusty East Winds will slowly diminish later today with warming aloft later this week and strong temperature inversions expected….The Weather will likey remain dry for a week or two…….

Thursday December 7th:

There is not much to add to the previous discussion other than to emphasize that this pattern is all about the big Trof in the East and the other Trof in the mean north of Hawaii. The Dweebs know that when the big Trof in the east moves out to sea, the west coast ridge will weaken and some energy will more through. Whether it brings just wind and cooling or some light snowfall it is not known at this time. However, the timing appears to be about the middle of December for this to take place. I have been writing about teleconnections a lot lately. During a winter like this, they really can give a better picture to what is happening, as well as to add support to what the models are doing with our future weather.  Things to watch for:  Feed back mechanisms like wide-spread snow cover developing over the Great Lakes Region and Eastern US. Also the development of anomalous warm water along the west coast.  These two feed back systems if established would be a future concern to the persistence of a dry southern and central west coast winter pattern.  The current pattern if it persists could be perpetuated into the winter if anomalous warm water develops along the west coast (+PDO) in conjunction with a large-scale snow pack in the mid west and east.

On a positive note, the *Climate Forecast System”  is still consistent in a break down of the current Ridge Trof pattern over the CONUS and develops a teleconnection of a strong negative phase EPO and WPO.  This along with at least a neutral “PNA” should return storminess to California with needed precipitation toward the end of the year and into January.  The Global models EC and GFS should have decent visibility as to this change in about 6 to 10 days. Although it is always possible to go from one drought pattern to the next, I trust the EC quite a bit as its physics are better at long distance than the GFS.

By the way, I have chatted lately with several locals here in Mammoth that have been up on the hill skiing and boarding. All have indicated that snow condition are very-very good. Comparing ski reports over California,  Mammoth Mt certainly has the very best snow conditions in California with the most snow pack reported of all the resorts. Mammoth Mt reports a 5 foot base over the upper elevations due to receiving more than 6 feet of snow during one of the AR events of November. The lower slopes has about 2 feet and they have been adding to that base with their extensive snow making system nightly. Over the past few days, it has been cold enough to make snow during a lot of the daytime hours and all night.  This includes The Little Eagle area as well as Canyon Lodge. Skier’s and Boarder’s are going to be amazed how good the skiing is when they are up for the holidays! 

 

More Interseasonal outlooking….

Below is the Weeks 3 and 4 500MB outlooks from the Coupled Forecast System/Upper height anomalies at 18,000 feet; Note the Red (Positive Height Anomaly (Blocking) over Alaska and Siberia and the Green (Negative Height anomaly) on the week 4 chart at the bottom. Also note the Blue Color “The Polar Vortex” becoming stretched out shifting well east. This is far from where it has been.  Note the Green (negative height anomaly below the Red on the week 3 chart, (Rex block) morphs to a full high latitude block in the WPO and EPO region. The Negative Height anomaly gets established over the Pacific Northwest.  If this verifies, this should be a good pattern in late December and early January for badly needed precip over the Central and Northern Sierra. This looks to be a colder pattern as well.

 

Dr Howard and the Dweebs………………………:-)

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It is another clear cold morning here in the Eastern Sierra. As the western ridge continues to build over the entire west coast and even up into Canada, a strengthening cold surface high over the Great Basin with a general off shore flow pattern is expected to prevail for several days.  Air Quality will diminish for those who live in the Eastern Sierra. Expect hazy conditions both day and night beginning Wednesday. This new pattern initiates with a strong east-west gradient. Gusty easterly winds over the Sierra Crest will slowly diminish over time, then briefly increase again Wednesday night. Mammoth Mt was reporting easterly gusts to 70mph range this AM. Again, winds will gradually diminish over the upper elevations as the gradient relaxes. At the Same time, warming aloft will begin today with the freezing Level expected to go up beyond 11,000 by tomorrow Wednesday. Once reached, an 11,000 foot freezing level will continue through the weekend. High temps will climb into the 50s later this week at resort levels while lows at night will rise to the 20s and 30s.

This pattern over the far west is part of the infamous positive phase of the Pacific North American (+PNA). Its key teleconnection lies over BC, Canada were it is anchored. When teamed up with a strong negative phase of the Arctic Oscillation (-AO) (Anomalous high heights over the Arctic) This pattern along with a northern hemispheric four wave, (long wave pattern) is very stable and unlikely to change anytime soon. The Climate Anomalies from todays run of the CFSv2, shows a 500mb positive height anomaly remaining anchored over the far west for both week’s 1 and 2, or through the 18th of December.  During week 1, the 500mb Height anomalies axis is located about 120west or over the Sierra. During week 2 it may shift east to about 110 west.  This eastward shift may bring further warming to the Owens Valley as there maybe periods southerly flow. By week 3 the interseasonal climate model shifts the northern part of the upper height anomaly over Canada further east to about 100West away from the PNA region, while the southern portion of the block remains strong over the Desert Southwest. This change will allow the westerlies to move back into the west coast from about Northern CA northward to Washington State. So the potential of an “AR” exists for the coastal regions of the PACIFIC Northwest. It would be primarily warm air advection precipitation over Northern CA, and most likely rain except for the highest elevations. Based upon this mornings run, most of it remains to our north and that may be a good thing!

The week 4,  500MB height anomaly if we choose to believe it, definitely shows the Break Down of the +PNA pattern over the far west and SW Canada. So the pattern goes into transition, the last week of December. Yesterdays European EPS, PNA region showed the +PNA dropping to neutral by the 28th of December. What is even more encouraging is that the Western Pacific Oscillation goes negative about the first of January and the Eastern Pacific Oscillation goes negative beginning the first week of January as well. These two Teleconnections indicate that high latitude blocking high pressure aloft will develop between Alaska and the Bering Sea during the first week of January and into the 2nd week.  PS. The AO goes positive the first week of January, and so there is the possibility of less Meridianal flow. This may allow the pacific jet to make its way to the west coast again.

Just using these teleconnections along with a negative PNA, tells the Dweebs that a stormy period will take place possibly beginning sometime toward the end of the month of December. The odds will then increase through first half of January. Of course, the Dweebs will have better visibility in about 1 to 2 weeks.

Stay Tuned……………………..>>>>

Dr Howard and the Dweebs………………..:-)

Chilly Today with strong Easterly Winds over the crest developing this afternoon…..It will be fair and milder later this week…..Dry weather is expected this week….

Tuesday AM:

It is another clear cold morning here in the Eastern Sierra. As the western ridge continues to build over the entire west coast and even up into Canada, a strengthening cold surface high over the Great Basin with a general off shore flow pattern is expected to prevail for several days.  Air Quality will diminish and those who live in the Eastern Sierra. We will note hazy conditions both day and night. This new pattern initiates with a strong east-west Gradient Aloft. Gusty easterly winds over the Sierra Crest will slowly diminish over time. Mammoth Mt was reporting easterly gusts in the 70mph range this AM. Again, winds will gradually diminish over the upper elevations as the gradient relaxes. At the Same time, warming aloft will begin today with the freezing Level expected to go up beyond 11,000 by tomorrow Wednesday. It stays there pretty much through the weekend.

This pattern over the far west is part of the infamous positive phase of the Pacific North American (+PNA). Its key teleconnection lies over BC, Canada were it is anchored. When teamed up with a strong negative phase of the Arctic Oscillation (-AO) (Anomalous high heights over the Arctic) This pattern along with a northern hemispheric four wave, (long wave pattern) is very stable and unlikely to change anytime soon. The Climate Anomalies from todays run (DEC 5th) of the CFSv2, Shows a 500mb positive height anomaly remaining anchored over the far west for both week’s 1 and 2, or through the 18th of December.  During week 1, the 500mb Height anomalies axis is located about 120west or over the Sierra. During week 2 it may shift east to about 110 west.  This eastward shift may bring further warming to the Owens Valley as there maybe periods southerly flow. By week 3 the interseasonal climate model shifts the northern part of the upper height anomaly over Canada further east to about 100West away from the PNA region, while the southern portion of the block remains strong over the Desert Southwest. This change will allow the westerlies to move back into the west coast from about Northern CA northward to Washington State. So the potential of an “AR” exists for the coastal regions of the PACIFIC Northwest. It would be primarily warm air advection precipitation over Northern CA, and most likely rain except for the highest elevations.

Based upon this mornings run, most of it remains to our north and that may be a good thing!  The week 4,  500MB height anomaly if we choose to believe it, definitely shows the Break Down of the +PNA pattern over the far west and SW Canada. So the pattern goes into transition, the last week of December.  Yesterdays European EPS PNA region showed the +PNA dropping to neutral by the 28th of December. What is even more encouraging is that the Western Pacific Oscillation goes negative about the Frist of January and the Eastern Pacific Oscillation goes negative beginning the first week of January as well. There two Teleconnections indicate that high pressure aloft blocking will develop between Alaska and the Bering Sea the first week of January and into the 2nd week. Just using these teleconnections along with a negative PNA, that tells the Dweebs that a stormy period will take place beginning sometime toward the end of the month of December and most likely into the first half of January. Of course, the Dweebs will have better visibility in about 1 to 2 weeks.

 

Stay Tuned……………………..>>>>

 

Dr Howard and the Dweebs………………..:-)

 

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Monday AM:

It is a beautiful morning in Mammoth with clear skies and cold temperatures…..10 degrees at the village!  Last little wave of the westerlies is currently moving through, resulting in a reinforcing shot of cold air. Mammoth Mt will be making snow today and tonight and  for the next 24 to 36 hours.  The aforementioned wave will increase easterly winds later today over the crest while the lower slopes will experience light winds. Winds over the crest will increase to 80MPH by tonight out of the East.  This little ripple is the last shot of cold air before the full latitude ridge sets up. This ridge has legs and will likely last for at least one to two weeks. The Upper Ridge will shift slightly east week 2 and that will allow the beginnings of some southerly flow to boost temps up in the Owens Valley next week. The Climate models (CFS) shifts the mean ridge position a bit more east weeks 3 and 4. However, 500MB heights remain pretty high over the Christmas holiday period.  I would suspect that we’ll see some AR precipitation beginning later during the 3rd week of December into the end of the year. The Dweebs note that in todays interseasonal Climate Models run, our air mass will be warmer than normal and that high elevation snow would be the more likely scenario, if we have precipitation during week 3 and possibly week 4. The CFS also suggests the absence of any blocking upper height anomalies over or near Alaska during weeks 3 and 4; IE -epo or -wpo. That is inconsistent with the EU EPS that came out a few days ago as it touted different teleconnections.

I will update “on the EPS”,  later this week to see if there are changes to its teleconnections in the WPO and EPO regions.

 

Some thoughts this morning……

  1. At the moment, there is no doubt that there will be plenty of Great Lake, Lake effect snows over the coming two weeks. The Dweebs are just not sure that based upon the precip anomalies forecasted by the CFS for the Ohio Valley and east, that significant snows will be accumulating in areas that there would be enough for the feed back necessary to anchor this pattern in the long run. Although that is certainly possible, it just remains to be seen. On the same thought, without the feed back, we could see this pattern break down quicker or at least gets some decent storminess in here for a while.
  2. The pattern shift suggested by the CFS this morning would allow for a significant AR into California after Mid Month. However,  odds are it would be warm with high snow levels as there does not appear to be any cold air confluence with this interseasonal pattern shift, at least based upon this mornings look.  On a bright note, Mammoth Mt usually does much better for snowfall from AR events as compared to Tahoe, because of its elevation….:-)

Sensible weather:

Expect a couple of cold days, with warmer weather the second half of this week. Daytime highs will go from near 30s today and mid to upper 30s Tuesday,  to highs up into the 50s during the day by Thursday and into the weekend. The cold temps at night and early mornings as of late will moderate into the teens and 20s at the Village. By the weekend, expect lows in the 30s by Saturday.  It will be much colder over the lower elevations of town during the early AM hours the 2nd half of this week. IE Strong Temperature Inversions and diminishing air quality is likely!

 

More later after the new EPS is released this week….

 

Dr Howard and the Dweebs……………….:-)

Chilly Upper Trof Axis has pushed east of the Sierra Now and so Sunny skies are expected Sunday…..What appears to be the last shot of Cold Air will Follow Monday….Then its Ridge City for quite a while….

Today is a blustery day in Mammoth with light snow this morning and currently sunny skies. High temperatures today will be in the mid 30s and gusty west winds will make it feel even colder. Lows tonight are expected to be in the teens. There appears to be one more shot of cold air following this trough, between the upper ridge now crossing 140W and the Sierra Crest.  This short wave is dry, but will bring some high clouds, some breezes over the upper elevations and more importantly, a shot of cold air Monday for which Mammoth Mt will be able to make snow day and night. By mid-week,  the upper ridge now progressing toward the west coast will amplify, forcing the freezing level up to 10,000 feet by Wednesday night and over 11,000 by Friday. This west coast ridge is likely to become stationary for sometime. Possibly 2 weeks according to the Euro Model/(Mid Month). I suspect that the week 2 models or during the 2nd week of December, will have better visibility about a change in the pattern for the future.  For the Dweebs…..An important indicator that will give an even longer look down the road will be the RIMM Phase Space, showing where the locations of potential tropical forcing will be. The strength of the signal and speed will be important as well. The speed of the signal can give an indication of what it is.  IE, an MJO, Rossby Waves or Kelvin Waves. A “strong” MJO moving through the Indian Ocean in phase spaces 2 and 3 would  break down the +PNA and help bring retrogression to the pattern that is currently developing for the west coast and eastern US.   At the moment, the RMM chart this morning using the NCEP. (American Models) ,show more amplification within Phase 7 for week 2. This just intensifies the +PNA the following week, so this pattern setting up this week looks bullet proof for at least a week or two.

The good news is that Mammoth Mt received up to 6 feet of snow about a week ago and they are making snow nightly…….:-)  Skiing and boarding is reported to be very good!

 

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