Upper level winds on the increase this morning as short wave passes to the north……warmer today with increasing high level moisture Sunday afternoon

The high country is getting ready for a return to Winter after a very long dry spell.  As the Eastern pacific long wave ridge returns to the central pacific,  a deepening long wave trof will progress toward California early next week with the upper jet eventually digging as far south as Northern Baja, MX.  The first system will juice up our air mass Monday into Tuesday before a vigorous Cold front swings in from the west. At this time, it appears that all the ingredients are in order….. including strong orographics, deep moisture and strong UVM Wednesday to produce quite a winter storm.  Although precipitation will begin as snow Monday, it will be too warm to stick in town. Once the 1st short of energy comes through about Midnight….temps will fall with a better chance for some light accumulation on Tuesday. By Tuesday night the tempo will pick up with moderate snowfall a possibility then heavy snow likely Wednesday and a good part of Wednesday night. This is because that although the cold polar front is expected to come through during the afternoon, several trailing vort maxes along with the upper flow natural to the Sierra should keep an active pattern going into the night.   It looks like a good 3 feet possible on the plot by Thursday AM with the possibly of more snow over the Crest.  Currently…HPC is forecasting about 3.00 inches over our area by Thursday AM. Considering how cold the storm is in back of the front with several inches of snow falling post frontal….we should easily get 3 feet plus by Thursday AM. The Dweebs will be updating the QPF on a daily bases…

 Thereafter…..another system may effect the Sierra by Friday, however the upper jet by then favors more Southern California  then Mammoth Lakes. It may be that we will just be an a cold showery pattern.

One more Notation:

There will be a potential period of strong  and possibly damaging winds in some of the valley locations including Crowley between Monday and Tuesday. More on the strong wind possibility’s in a later discussion Sunday as more information arrives from the National Weather Service.



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.

Last really mellow day today then winds on the increase as well as temps this weekend…..Storm/Timing still good for next week!

All large scale features still preforming well as forecasted, with upper pattern morphing toward a temporary REX block near the dateline Sunday afternoon. This is always good for the generation  of tropical and subtropical moisture for storms to feed upon at a later time.

 The eastern pacific upper ridge continues to progress into California as it becomes squashed over the area Saturday. On a smaller scale…..heights increase over Mammoth this weekend as  a short wave moves through the pacific northwest. This has the effect of increasing winds at 700mb and so it will be quite breezy over the upper elevation Saturday and at the same time, temperatures will actually be warmer.  By Sunday afternoon…the ridge axis shifts east into the Great Basin and the door opens to high level subtropical moisture along with stronger gusts over the Sierra Crest. The new 12z Friday GFS has a lot of upper level moisture advection at 700mb (rh) rushing in during the afternoon Sunday….so it is possible that although Sunday morning may be mostly sunny……then by the afternoon cloudy. 700mb winds will continue to increase Sunday PM.

Synoptic scale timing: 

Just using the new deterministic 12z Friday GFS for timing. 700MB (rh) has slug of mid level (50%) moisture into the Sierra after midnight Sunday night increasing to 70% by Monday mid morning then up to 90%  by late afternoon Monday. Initially, this is moisture advection without any dynamics from the subtropical 1st short wave.  Nevertheless, orographically induced light precipitation is possible as early as Monday morning with the chances increasing during the afternoon.  The actual energy and dynamic lift from this 1st subtropical short wave comes through during the early morning hours Tuesday. Thereafter….a larger scale Trof deepens with a vigorous cold front coming through Wednesday afternoon with heavy snowfall both frontal and pre-frontal. Snow levels may drop to 3500 feet by Wednesday night.  700mb winds natural to the Sierra may keep orographically induced snowshowers  going up to about 9 to 10z (UTC) Thursday am.  It is still too early to really predict how much snow we may get. However, the Dweebs have a 1st call of 2.5 feet over Mammoth Mt. by ooz Thursday…..just a guess at this time.

Longer Range: 

The longer range models still has the long wave ridge in the mean back between Hawaii and the dateline which is good. However, the GFS is beginning to display typical characteristics of Spring with an incipient trend of cut off lows during week 2. Once we get to March which typically begins cut off low season, week 2 reliability begins to diminish.  Additionally…looking at the fantasy charts of the GFS, the energy coming off Asia and Japan becomes split.  This often times creates a split flow pattern for the west coast. Of course, where the split occurs is what is important.

Although March is typically a very wet month on the average, this is an La Nina year. La Nina winters are usually more intense but shorter precip seasons. It may be that Cut-Off low season will begin earlier this year?

Future timing of “significant energy” through west coast “week 2”.

1. Night of Friday the 18th

2. Thursday morning the 24th


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.

Cold inside slider brought some light upslope last night…..Light Mono Lake effect probably helped……Nice weekend shaping up with light winds followed by Storm Tuesday

Lee Vining and June Lake picked up a little lake effect over night. Infact some lake effect was still occuring at this time.  West coast upper ridge to begin reacting to pattern change as strong height rises are now occuring near the dateline and a deepening trof is digging south along 150w. The effect upon west coast upper ridge off shore are profound this weekend. The off shore ridge gets flattened with its high heights squashed into the west coast beginning Friday as it gives us a beautiful weekend! Winds will be light this  Friday, Saturday and Sunday with highs in the 50s Saturday and Sunday at resort levels. Heights peak out Saturday at 00z Sunday and temps will reach into the low 70s in Bishop Sunday. (Golf anyone?)

The next shoe to drop will be the rapidly approaching lead short wave with a fair amount of subtropical moisteure. The timing from the GFS seems pretty good now with the energy expected to come through Tuesday. Cylke’s Law says 12z Tuesday as the 1st iso bar reaches 150E at 12z Friday morning. 96 hours of propagation says energy to come through 12z Tuesday.  So snow fall could begin any time after Midnight Monday night. 500ht Heights are around 552dm at that time, so a snow level around 6000 to 7000 feet to begin with seems good depending upon the dew point and 700mb temps. The nature of the moisture is subtropical so it may end up a bit higher to start with. At the moment…..the isentropic surface along with the front slide through Southern Mono during the afternoon Wednesday. With some additional energy coming through Wednesday night.

A following shot of energy comes off Japan about the morning of the 14th. Although it really does not spin up for another day. Will watch that one the next couple of days….



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.