Cooler Weather and Quite Breezy Over The Upper Elevations Sunday

Just a quick update this morning…

It’s very breezy over the upper elevations this morning. With the ambient temperatures in the 20s today dress warmly up on O’l Woolly!

Strong upper jet NW-SE  Cutting through Nevada today. Dry cold front will slowly make its way through southern Mono County later this afternoon. A wind shift should occur for the Owens Valley tonight and so expect north winds to really pick-up this evening. (15 to 30mph)

Highs in the Town of Mammoth will be a bit higher then forecast as the front has slowed down. As of this writing,  the town has probably peaked on temps  for the day (33 degrees)…..while night time lows will drop into the single digits. Light breezes are expected for the TOM.

For the coming week…the main storm track will be well into the pacific northwest. For the Central Sierra,  expect mostly light to possibly moderate warm advection type (Isentropically lifted) precipitation. So some light snowfall is expected Tuesday and Tuesday night. There will be some chance of light snow throughout most of next week. Snow levels will rise most of the week. High temps will go from the mid 20s Monday to the 30s by Tuesday into Thursday then into the 40s by next weekend. There is still a possibility of a January thaw the following week.

The key to our longer range I believe is whether or not a MJO develops week 2 and modulates the westerlies as the NAO is going to be in the positive mode toward the longer term.

See: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

LA NINA is still raging!…….

See: http://weather.unisys.com/surface/sst_anom.gif

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

High Cloudiness Invades Mammoth This Afternoon With Dry Cold Front On The Way…..Warm Advection Snowfall Still On The Way For Tuesday And Beyond…..

What does January 4th, 2011 and January 4th, 1983 have in common? They both have very nearly the same amount of water content upon Mammoth Pass to date. Some other interesting notes…  The winter of 1983 was the wettest winter on record according to DWP for the Mammoth Pass.  Now for the Irony. The winter of 1983 was associated with the strongest El Ninos on record! The winter of 2011 is so far associated with a La Nina that’s one of the strongest on record so far.  Wet La Nina….Wet El Nino!    See:   http://www.ladwp.com/ladwp/cms/ladwp013390.pdf


Current Weather:

By 8pm or 9pm tonight a dry cold front will push south of our region……Aided by an upper jet approaching 150knots by Sunday PM across Nevada. Temperatures at 700MB are forecasted to be as cold as -10C on the east side of the Whites and on the west side… -6.5C. Nevertheless another dump of cold air is destined for the high altitude valleys that just got done with temps as cold as -20F.  There will be some -10F locations by Tuesday Am.  

The big forecast challenge is whether or not the valleys get some freezing rain next week along the highway 395 corridor….. Or will it be below freezing through the column?

For the Mammoth and June area, the Dweebs expect periods of light snow fall on and off through the end of the new week. Some days possibly an inch or two, others days 3 to 6 inches within any 12 hour period. Thursday looks a bit better for a system that may bring a bit more.

The Big picture:

Overall this coming week, the models maintain and agree that the high latitudes will remain blocked up with a strong -AO. The big Alaskan block will drift slowly west northwest from northeast AK into Eastern Siberia. Through the process…..the westerlies will undercut the big block and merge with a deepening trof in the mean over southwest Canada.

The tempo will pick up later this week as the storms will move faster under the block.  At this time….it appears that the Town of Mammoth Lakes will be mostly south of this storm track. Precipitation should be Light to at times possibly moderate later in the week.  The Dweebs Snowfall Criteria for Mammoth…..Light: 1 to 6 inches within any 12 hours period; Moderate: 6 to 18 inches within any 12 hour period.

With all that said there are some ensemble members that have the storm track further south into Central Ca later in the week. However, for the time being….the majority keep the brunt well to our north.

Again it appears that Mammoth will have a week of warm advection precipitation. IE…..isentropic induced snowfall.

Note:

There will be something to watch out for after the 15th:

Is the the Dynamical Model MJO forecasting a rapidly strengthening MJO later this week that will move well into the Western Pacific the following week?

See; http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

Never a Dull Moment!

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


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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Northwest Slider To Bring Cooler Air To Mammoth By Sunday….Some Light Snow Possible Tuesday Into Thursday…Then January Thaw A Possibility Thereafter…..

Inversions weakened over the past 24 hours and Mammoth AP Thursday morning which was -20F. This mornings over night low only was only +1F.  The strong upper ridge and surface high that kept the cold Arctic air from the previous storm trapped in the lower high elevation valleys this week is weakening…..

The next changes to our pattern:

1. Upper cut-off low off LA is currently ejecting through Southern Ca today bringing a few showers possible to the higher terrain.

2. A Northwest slider off the Southern BC coast is acting as the kicker. This system will develop quite an impressive upper jet the next 48 to 60 hours, after which couples with a mid latitude jet  into NW California  Saturday. No doubt there will be an increase of wind over the Sierra Crest later Saturday Afternoon with stronger winds Sunday into Sunday night.  The new 12z Friday GFS shows 300mb isotachs over NW Ca at about 70 knots which then increase to 110knots by 4:00am Sunday.

By late Sunday afternoon, the upper jet at 300MB is diagonally slicing through Central NV with a 135 knot upper Jet. This will keep the upper elevations of the sierra crest winds going….bring further cooling to our region and even the slight chance of some flurries or snow showers as the right rear entry region passes off to the southeast on Monday. Daytime highs for Monday in Mammoth will drop to the low to mid 20s.

3. In the systems wake…colder air will advect in. This will eventually be the lifting mechanism for several mid latitude short waves coming up from near Hawaii Tuesday….Wednesday….Thursday and Friday. These will be all warm advection precipitation producers. Will it be light or moderate in amounts?  Too so0n to tell. Warm  advection precip is some of the most difficult to forecast here in the Eastern Sierra as far as amounts. So for you snow plowers…..don’t take that trip to Mexico just yet. Your hall passes are canceled until we see if the  proposed “January Thaw” is going to be real or not!

4. The long range models are deepening the Hudson Bay Low in last nights 0000 UTC GFS  500mb Height/Anomaly Forecast 7 Day Mean, Centered Day 11 (10 days out). This looks like a January Thaw Pattern.  However, looking at the new 12z Friday deterministic run of the GFS , I have my doubts on how long any period of fair weather will last, as that key negative height anomaly (Hudson Bay Low) does not seem to like the Hudson Bay area very much this year. Thus, any strong loading of the +PNA will probably be short lived?


As usual…we’ll see how it all develops……………;-)

The Dweeber

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.