Western Pacific Jet May Come To Our Rescue….Next Week

Another system will push into the pacific northwest tonight bringing a lot of rainfall to coastal sections Northern California northward. The upper ridge over the far west gets flattened Wednesday with the chance of some light snowfall here in Mammoth above 7500 feet, Wednesday pm into Thursday. The pattern is considered unsettled and won’t bring much in the way of precip for the Mammoth Area. Wednesday, Thursday into Friday may be unsettled… then a very nice weekend. Temps will stay mild in the 40s with over night lows in the 20 and 30s.

It will be windy Wednesday/night.


Outlook:

Yesterday and days before…the Dweebs highlighted the possibility of the enhanced tropical mode of MJO strengthening over the Maritime Continent. See the latest MJO Discussion at: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

For good technical MJO explanation see: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/MJO_summary.pdf


Those at CPC will be watching to see if the enhanced tropical rainfall mode of MJO actually develops over the Maritime Continent. (A quick look at that area looks pretty convective to me);  MJO often times modulates the westerlies when in the right phase…..Moving from the Maritime Continent to the Western Pacific. It can spawn western pacific tropical storms that effect the westerlies as well as.

The Dweebs are not sure if it is MJO that will bring about the big changes hinted in the past three runs of the global models…..

Having a look at last nights and this mornings global model runs…..ooz, o6z and 12z GFS. It is very evident that we are going to have a decisive shift in the long wave features eastward some 20+ degrees next week. This gets accomplished by a very strong, consolidated upper jet coming off Asia, extending well into the Western Pacific by mid week next week. The upstream long wave trof near Korea is extended eastward as well.

The big result is that the static block now just east of the Dateline progresses eastward to 160west and the long-wave trof shifts to 130W.  As the pattern develops further….there was suggestion in this mornings opperational 12z gfs run, that there is a break through of the westerlies under the block with a healthy subtropical branch confluent with the polar jet into Central Ca the 17th of Dec. Before that happens…the off shore trof now at 140w get pushed into the west coast about the 15th/16th.

In the meantime…enjoy the fab weekend coming up…..then get ready for some real WX next week!


The Dweeber……………….:-)


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Reference Glossary of Weather Terms

No Doubt About It….Major Blocking Has Developed Near The Dateline And Northern Atlantic…..Subtropical Ridge To Keep Most Storms Well To Our North

We’ll the Dweebs knew it had to happen at some point this La Nina Winter. The NAO (North Atlantic Oscillation) has gone pretty Negative, and as well, the -AO (Arctic Oscillation). This teleconnection simply put, keeps the East colder then normal and the west warmer than normal. The far west should be quite wet from Northern Ca, northward. The Atlantic block will also continue to import cold frigid air with some interruptions…into parts of Europe for several weeks.

If you remember, the early part of January this year was highlighted by record -AO and -NAO standard deviations from  normal which brought extreme cold to western Europe and the eastern CONUS. It looks like a repeat of that is in the cards once again.

The West Coast:

For the most part this season, the strong pacific jet has come to our rescue in freeing blocked up patterns. A MJO in October of this year was an example. But of course blocking in October is nothing like Blocking in Dec and Jan!  The Dweebs are hoping that a current developing MJO will spin up the jet over the western pacific in the coming week or two and eventually cause the Pacific Block to break down. 

Looking at the Wheeler-Hedon Phase Space, I have to admit, I am not all that impressed this morning with the progress of this developing system over the Maritime Continent. The CMET and UKME seem to have the best handle on it. Even so, they are not all that impressive in their forecasts over the next two weeks.

Last Night’s Storm:

To sum it up, fast and furious!

It began snowing just after halftime during the other battle going on back in Baltimore. The way Ben R. played, in my estimation, the Steelers deserved the win! 😉

So between 7:30pm and midnight, it snowed at a rate of a good 3 to as much as 4 inches an hour. So much for moderate snowfall! 🙂 

By the way….my Ol’ buddy the late Don Marcellin, once told me that during the winter of 69…It snowed at rates between 6 and 12 inches an hour!  Do you think that would qualify for R3 conditions?

Expect a mostly sunny day today with strong gusty winds over the upper elevations decreasing tonight.

Highs in Mammoth today near 40….lows in the teens. It will be a pretty mild week for the remainder of this week. There will be a period of over running Wednesday. However, most of the precip will be well to our north.  This pattern with the Blocking high over the Dateline may last for a long time. Unless some how we manage to get a strong destructively phasing  jet developing over the western pacific….we may have to be content with short periods of storms that occur only when the block temporarily breaks down or weakens. Thus allowing a progression or an extension of the 140W long wave trof to sneak some energy into the Central West Coast.  One thing looks inevitable…that the pacific north west will eventually get hosed from the tropics this year!


The Dweeber……………….:-)



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Reference Glossary of Weather Terms

Snowfall To Become Moderate Tonight…..10 to 15 inches over Mammoth Mt. by Sunrise Monday

No surprises this morning. There is a nice break in the weather with mostly clear skies at the moment. However….the leading band of subtropical moisture has already made it to the crest as I write. More of this high cloudiness may invade the Mammoth sky later today.  Winds were 10 to 15 mph at the main lodge and gusting to 40mph over the top of Ol Wooly. Winds will increase further today. There is a chance of showers today, especially later this afternoon.

The new 12z model runs are in. Our closed upper low off shore bottomed out over night. It has since  made the turn to the northeast toward the Northern Ca coast. There is a large swath of tropical and subtropical moisture southwest to the ITZ. However the vast majority of all that will be cut off shortly,  before it can become entrained into the west coast system. It appears that only a small amount of that will actually effect our area today. Looking at the current IR sat motion.  The upper low looks strong with good convection evidenced by lighting detection.


The cold front will sweep in tonight in advance of the main vort center that will move on shore late tonight. In that the upper low comes in negitive tilt…strong divergence aloft is noted and so dynamically, it will bring in a strong but short period of UVM. Here in Mono County, orographics are decent but not overly impressive during the main FROPA.


All in all, this system is certainly capable of some 12 to 15 inches over the upper elevations. The updated CRFC brings the crest about 1.4 inches, so we may actually get a bit more…up to 18 inches over the crest.  However, snowfall will taper off quickly eastward….with only 2 to 4 inches expected in the community of Crowley Lake.

At the Village at Mammoth (8050), I expect some 5 t0 10 inches. Most of this will be over with by sunrise, with little accumulation between 15z and 20z.


Longer Range:


The Dweebs are keeping up with the longer range. The Screaming message is still the big block very near the dateline through the 15Th. As long as that block remains in place there….. the downstream negative height anomaly will stay stuck pretty much at 140w. That keeps us well south of the upper jet with above normal temps, moderately high freezing levels and with periods of over running. There is a subtropical ridge  currently centered off Baja that will move both north and south depending upon how amped the pattern is. 

As a note, the Dweebs were concerned about the warm water west of the dateline with prospects of ridging near the dateline and the corresponding down stream ridge dear the west coast. The Dweebs believe that this is indeed happening. Although there is some +SSTA that has moved north of Hawaii, the vast amount is still west of the Dateline….La Nina Style!


MJO:  One of the great pattern changers is MJO. This morning….there is increasing confidence that a new MJO is emerging in Phase 4 (Maritime Continent) of the Wheeler-Hedon Phase Space.

See: http://cawcr.gov.au/staff/mwheeler/maproom/RMM/phase.Last40days.html

If this feature continues to develop and strengthen and then move from phase space 4 to 5 then to 6, profound changes will occur over the Central and Eastern Pacific. This area of growing  tropical enhanced rainfall will more then likely modulate the westerlies and progress the long wave upper ridge near the dateline eastward, thereby adjusting the long wave Trof currently near 140w, eastward toward the west coast.


Stay Tuned………………….!


The Dweeber………….:-)





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Reference Glossary of Weather Terms