Expect 5 feet of Wind and a few inches of Snow from the Tuesday system then fair and warmer Wednesday into Thursday before the next system moves in Early Friday into Saturday…..Longer Range Discussed….
Monday April 21, 2014
Posted at 8:58 am by Howard
Tuesday AM UPDATE:
FROPA occurred about 8:00am this morning and the period of moderate snow has ended as well. It was nice to see some snow falling as it has been a while since that has happened. Mammothweather.com picked up close to an inch of snow while the roads being warm from the past couple of days of low 60s showed wet streets in town. Mammoth Mt probably picked up 1 to 3 inches top bottom. Outside of some scattered snow showers little in the way of accumulation is expected the rest of the day…..possibly another inch or so… The WX front is moving through the Owens Valley at the moment with strengthening winds…A high wind warning is in effect for the Owens valley today.
It will be some 10 degree warmer Wednesday and another 3 to 4 degree of warming is expected Thursday. Highs in the upper 50s for Thursday.
The next significant weather system will move into the area about Midnight Thursday. The GFS is back to the idea of digging the Vort center further south as the system splits. It is interesting to note that there is still a small pocket of -30C at 500MB up over extreme Northern CA Friday AM. However, at 700mb, as the -10C approaches the central coast by 18Z, as the split occurs, it gets left up over Northern California. Thus the energy headed for the Central Sierra weakens rapidly Friday Afternoon.
So the latest 12Z GFS model run continues to waffle while the EC still has more of a consolidated system coming through for Friday. At this point, given the time of year, the GFS may have the better solution. However, in looking down stream, I do not see any real blocking to cause this split. Everything seems pretty progressive across the country, although ridging is starting to build over the nations midsection. So the upshot here is if the GFS is correct, QPFs of at least half of what has been touted the past few days will occur resulting in snowfall amount’s of less than a foot. I will wait for another run or two of the EC to see if it too has the same idea. Will report later today, time permitting.
I forgot to mention that there is some over running coming in Saturday late AM into the afternoon lasting into the evening. This is from a strong northern pacific upper jet of a good 150 knots. It is riding atop of a building eastern pacific ridge that will eventually build over California early next week.
By late Tuesday, temps at 700MB will approach +7.5C over Mammoth and up to +10C over Southern California. This is quite the Anti-Cyclone and quite warm. Back to the over running…There is not much QPF from that system. Over running is just mid level moisture over running the cooler air in place. So there may be a period of light snow or showers during in the day Saturday into the evening. Thereafter, we ridge up early next week with vengeance and remain fair for sometime. As I mentioned in the past discussion, we may have another active pattern develop the 2nd week of May according to the Air-Sea coupled CFS. I will report on that later in the week.
Dr Howard and the Dweebs………………………………;-)
Local forecasts will reflect an increase of wind this afternoon along with lots of high cloudiness….
The weather system coming in Tonight will favor the Pacific Northwest as the main forcing and upper “jets” couple up over the pacific Northwest today. The Rt rear entry region passes over Mammoth Tuesday AM and thus that will be the best time for showers locally. The snow level will begin high. About 8500 tonight then fall to about 6500 by AM. The best time for showers will be about 15Z Tuesday. (8:00am) as a small area of 50% RH at 700MB moves through with the approaching vort center and WX front. The last Vt max will be east of Mammoth by 21Z Tuesday. Amounts??? 1 to 3 inches. Best Guess…
Upper ridging will follow, however, it is short wave ridging. This leaves the door open for an even stronger system Friday. The new 12zGFS has the cold pool at -2.5 SDN) What I did not like about the 06Z run last night was the system splitting with a closed upper center developing off the SC coast Friday night. This would reduce the QPF substantially. However the 00z ECMWF and the new 12Z GFS runs has the system holding together better. The New 12Z gfs has the upper low closing off over interior CA after the main dynamics has moved through the Mammoth area Friday. Friday is ShowTime….Saturday is just cold and showery with the possibility of some mid morning upslope.
So the way things look today….The upper jet still hooks into and through Paso Robles which is not only known for great vineyards but also one of the best upper jet entry regions for the Mammoth Area! 😉
This will be a plow for the snow pushes in town Friday Evening with clean up Saturday AM…
It is looking like 12 to 18 inches over the upper elevations at this time.
Expect warming temperatures Sunday into the following Monday.
Once again I had a look at the CFS (Climate Forecast System) for the long range. Here are my thoughts…. Normally, in many La Nina years, winter ends quickly. Summers are often warmer then normal over the interior of the Great Basin away from the coast as its colder waters effects the marine layer. However, we are no longer in a La Nina, but trending quickly toward El NINO. The MJO that has been stuck in phases 6 through 7 much of the winter was not conducive or at the least did not add much support to precipitation here in Central and Southern CA . That became dislodged in March, possibly because of the great Kelvin Wave now sloshing up against the Central American coast. Over the past 45 days the MJO cycled nicely through phase’s 1. 2. 3, 4 , 5 and now 6. If that were to have happened in January and February we would have had quite a few good storm’s, based upon the MJO teleconnections.
So what has happened?
Argument for a wet May….A strong Kelvin Wave that began over the western pacific has slowly traveled across the pacific to the Eastern Pacific. The warm sub and surface waters have flipped the ENSO sign throughout most of the ENSO regions. If you recall during strong EL Nino Winters, they no not die quickly, they tend to fade away…..sometimes lasting into early July! Like during the winter of 82-83. Could the CFS which is a *Ocean/Atmospheric *coupled model be telling us that a cool Spring is in the making? The latest CFS Run has the precipitation over Northern and Central Sierra up to 130% of normal as well as 3 standard deviations of normal for the month. Of course, one could argue that we do not get much precip during the month of May anyway…..but this is significant.
Argument against a wet “Early May”:
Using the Dynamic MJO Model based upon the GFS Ensembles….the Location of the MJO in phase spaces 8-1 for the month of May suggests higher then normal heights over CA.
SEE: for phase 8 http://www.americanwx.com/raleighwx/MJO/MJO/MayPhase8500mb.gif
SEE: For Phase 1 http://www.americanwx.com/raleighwx/MJO/MJO/MayPhase1500mb.gif
So the question may be, what happens later in the month of May?
Dr Howard and the Dweebs………………………………….;-)
*The “Coupled” in the model’s name refers to the fact that the model couples both atmospheric modeling and oceanic modeling into one all-purpose model. Its forecasts are derived from a 16-member ensemble with each member initialized on a lead of several days worth of conditions. The CFSv2 offers output that can be masked to remove forecasts with insufficient skill.