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Archive for March, 2013
Northwest Flow Aloft to keep it Breezy over the Crest and Cool Through Friday……Diminishing Breezes Expected over the Weekend……Next Chance of Snow Mid Week Next Week…
Thursday March 21, 2013
Here is the latest on the Greenland Block. The (-AO,-NAO Combo)
Wow! Look at the coming break down of the block!!!!
AO index http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml
NAO Index http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif
PNA Index http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.sprd2.gif
Even though the PNA index has had nothing to write home about, the Block to the East over the north has….
The Dweebs believe that together, these two teleconnections have had more effect upon California’s dry weather this winter then anything else! Including the MJO
The forecast is for the block to weaken and fade away by the end of the month…..It is beginning to break down now…..Seasonally?
So the big long wave negative height anomaly that has been static over the east should finally push off into the Atlantic…opening up the wavelength for storms for the west coast. Don’t put away your boards just yet!!!
The central west coast storm door has a much better chance of opening up beginning the last 5 days of March…then well into April.
It may very well end up a wet April. More later>>>>>>>>>>>
Dr Howard and the Dweebs…………………..:-)
Current Storm System Off Shore Has Plenty of Fuel….However Not Much Spark! Nevertheless Mammoth Mt will get a nice Freshing of its Surface Mid week…..The Following Weekend Will be Fair…
Monday March 18, 2013
Tuesday Evening….
-AO and -NAO still is expected to break down by month end….
Technically, we should have a pattern change going into the end of the month…..
Say good-bye to Winter….Spring arrives at 4:02AM Wednesday….
What do you get with a juiced up atmosphere with no spark? A wasted opportunity that is for sure….
The Spark being referred to is dynamics. Dynamics creates lift. It takes lift in the atmosphere to squeeze the sponge. Where is the lift? Looking NW it is in the Gulf of AK. But the timing is off. The Moisture will get in here Tuesday and Tuesday night before the colder system with its lift does on Wednesday. The basic lift involved will be orographics. I do not expect more than a trace to an inch or two in town Wednesday. Snow level will be 7500 ft Wednesday.
Amounts will range from 6 inches to 10 inches on Mammoth Mt. Snow to Water Ratio’s ave 7:1 QPF from mainly orographics, .5 to 1.0
Of course this is not the whole story. There are more fundamental issues that are still causing the head winds, “figuratively speaking” and the persistence of the dry pattern we have been dealing with since the beginning of year. In short, the (-AO and -NAO Combo) have done a job on us this winter, and we are/will continue to feel its effects in a negative way until that system breaks down! Look at the standard deviations of normal in the -AO…almost off the charts!!!!!!! It is no wonder why the mid west and the east have had one of the snowiest winters in the last 100 years….
-AO: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif
-NAO: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif
Until the -NAO returns to at least neutral, its drought city for the central and southern west coast. Now this pattern was some what predictable by knowing that the QBO was heading toward neutral during the coldest part of the year. Remember that when the QBO index is in transition, -10 to +10 it points to a greater degree of certainty of the formation of the -AO/-NAO Combo) during Jan, Feb, March. Calculated at PSD (from the zonal average of the 30mb zonal wind at the equator), as computed from the NCEP/NCAR Reanalysis). SEE: http://www.esrl.noaa.gov/psd/data/correlation/qbo.data
Long Range:
From What the Dweebs see….That system will stay intact through the end of March and will slowly break down in April which may lead to a wet April into early May.
See CFS v2 500 hPa z For weeks 1 and 2 http://www.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk1.wk2_20130317.z500.gif
Weeks 3 and 4 http://www.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20130317.z500.gif
As you can see, the Block really breaks down in April….
Dr Howard and the Dweebs………………………………………..:-)
More Snow Expected Next Week……However Less Than Earlier Expected…….More Updates Next Week…….
Friday March 15, 2013
Sunday PM Update:
Models have come in a little wetter this afternoon with the EC generating up to an inch over the crest. I think that is good for the crest. This is for the period Tuesday through Thursday AM. The GFS is a bit dryer. However, it too is a bit wetter then last nights run. The subtropical system has already occluded and is cut off about 1000mi west of the central coast wine country. The system will combine off shore with a system coming out of the Gulf of AK…..but seems to dampen before moving inland producing a weakening front. Thus the lift will be mostly from orographics which will be decent and because of PWs of up to 3/4 of an inch the potential for 10 inches over the crest seem like a good bet now. SWE Ratios will be low….6 or 7:1 at the main lodge and 8 or 9:1 over the crest. There will be a lot of shadowing east of the crest so like the last system snowfall amounts will be unimpressive in town.
CNRFC has freezing levels over Yosemite Tuesday night over 9800 ft, and through Wednesday around 9500. If the atmosphere is saturated and isothermal, snow levels could fall into town. This is a big if through. Otherwise this will be a rain/snow event for the town…. Best guess an inch or two of slush.
Another update Monday…………………………………….>>>>>
Saturday Night Update:
Latest modeling is splitting the Wednesday system pretty badly. This is not going well as only light amounts now expected….
Will update Sunday….
Brief Update:
Next weather system will be still running into the head winds of the mean ridge position. The wavelength resulting form the ongoing Greenland block will cause quite a bit of splitting. The system looses a lot of its punch and the models both the GFS and the EC are less in agreement now. Usually when you get closer to an event the models come together. In that they are deviating….Not a good sign. Nevertheless, we will get enough snow to freshen up the base. If you biting down on the EC… the European has backed off a bit now on the QPF. Although it is still painting about 1.25 over the Mammoth portion of the Sierra next week. The GFS has much less. Still have time to watch it though. The Dweebs will update again Monday.
For those that wonder why I have not updated as frequently in the past three weeks. My computer was hit with a nasty virus. I hope to be back up only more frequently next week. If I find out who it was…I will give their address out so you may have your way with them. 😉
Some Rumor’s about a big storm at the end of the Month. Just RUMORS……..>>>>> Will take a good long look ahead next week……>>>>
The Dweeber………………………………..:-)
