Archive for March, 2013

All the Dweebs can say is Wow!  Our weather is way too nice for this time of the year…..

The strong upper high over California will weaken this weekend to allow considerable high clouds into our area beginning later Thursday.  Temps will remain in the low 60s until Friday when a slow cooling trend develops. The cooling is more due to falling heights and cloudiness then any cool air advection.

The next important change comes to the Eastern Sierra when the wave length opens up a bit across the Conus. Notably, Week 2 when positive height anomalies pull far enough north next week and allow more energy to break under the Greenland Block. This looks promising. I think…I mean I hope that the ECMWF has the right idea now as the latest GFS and GFSX has been coming over to its idea of a storm about mid week, next week.

The ECMWF is pretty wet. It appears to be taping into a mid pacific westerly flow (Subtropical jet) and is generously painting 2+ inches (QPF) for the Central Sierra next week between Wednesday and Friday night.  The GFS is looking promising as well.  However….I would approach this with caution as drought patterns like the one we have been in the past 8 to 10 weeks do not change that quickly. Rather…they tend to fade away with the seasonal change.

So try to enjoy the beautiful weather. I realize that it is difficult. 😉  I Will update this Saturday Night or Sunday the latest…..

The Dweeber…………………..;-)

Quick Thursday Afternoon Update:

Storm progressing nicely and as expected with nice deformation zone set up over Mono County. Snow will continue to fall tonight and into tomorrow. Looks like upper limits of 2 feet in the powder bowls will be reached by this evening as snowfall rates kicked up quite a bit this afternoon. Main lodge reported about 12 inches by mid afternoon. The Dweebs expect another 6+ inches over the upper elevations next 36 hours.

The storm exits during the day on Saturday, but not before dumping 12 to 18 inches at the main lodge and well over 2 feet on the crest.

For you Southern Ca Dweebs……

The weather system will finally move into the LA area tonight and bring some snow to the San Gabrials.  6 to 8 inches w/SWR up to about 3/4 inch.

Double barreled upper low was between 250 to 450 miles off the southern and central coast late this afternoon. Main front was moving east about 15 MPH. UVM will increase over the coastal plane and rain will increase late tonight in the LA area and valleys. Mostly light to moderate but there could be a few boomers as well for some brief heavy rain..  Freezing level lowering to near 4K over night.

Looks like were getting set up nicely for this month……

After a period of warm weather next week…the follow weekend may see a return to an active pattern………………..:-)

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Tuesday Am Update:

Latest CRFC QPF shows 1.04 for Yosemite

Freezing Level at 6000 to slightly above.

The heaviest most concentrated shot of precip will be with the front between 12z and 18Z Wednesday. (4:00am and 10:00AM) …then frequent snow showers through out the afternoon.

The 12z Tues GFS 700mb=Rh has has us in 90% with the Front mid morning then 70% Wednesday afternoon through Thursday afternoon. Then there is another RH max Thursday PM into Friday morning when we might pick up significant snow again.  It may be that we get as much snowfall behind the front associated with the upper low at 700mb Thursday night into Friday Am then with the front itself Wednesday AM.

The Dweebs still think that this is going to be a 1+ to 2 foot storm total by early Saturday morning on Mammoth MT. Again….There will be significant snowfall due to the upper low dropping south Thursday and the subsequent deformation zone setting up over Mono County Thursday night with up slope possible later Friday into the night. The Storm exits during the day Saturday.

Thoughts about the Winter……

Last year all the rage was that the AO was positive and the reason for the dry winter over the west was due to the +AO. Reading the studies and research….it is clear that the -AO teleconnection for the Far West means nothing!!!!!! Reason…  There is a non linear relationship between the -AO and wetter then normal winters over California. Anything else said is HOG WASH!!!!

Here is something to think about though.  The QBO…..

David Tollis a retired Meteorologist from the National Weather Service may be a little rough around the edges but he is a brilliant long range forecaster!

In his research, he researched the QBO signal and its affects upon high latitude blocking. QBO is  (The Quasi Biennial Oscillation) From wikipedia>>>The OBO is an alternating wind regimes that develops at the top of the lower stratosphere at 30MB and propagates downwards at about 1 km (0.6 mi) per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found. The whole cycle takes about 30 months to complete negative to positive and so it can be some what predictable.

OK So what…..

When the QBO is in its westerly phase (Positive phase)…strato winds blow from west to east.   When the QBO is in its Easterly Phase (negative phase) the Strato winds blow from east to west.

Strong positive QBOs correlate to Non Blocking weather patterns

Strong Negative QBO values equate to +AOs and +NAO patterns

(((However))) when the QBO is in transition…….  -10  to +10, it strongly forecasts blocking patterns over North America. So when it is accompanied by a strong -AO and -NAO you get a strong +PNA pattern over the far west.  (+PNA Pacific North American Cir pattern…..IE the big west coast perma-ridge in the mean)

So although when the -AO is strongly negative, the west does not benefit to high degree when the QBO is very weak!!!!!  That is probably in part why the relationship of the -AO teleconnection pattern is non linear to California weather!!!

See where is the QBO signal is today:   See http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

It is probably near 0.   What do we have currently. Big high latitude blocking over the northern hemisphere, -A0, -NAO, +PNA  Drier then normal California WX that past two months. Imagine that…….

The Dweeber…………………………..:-)