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Archive for March, 2018
Spring has Sprung w/Warming Trend in full swing; 50s and low 60s possible the next 3 to 5 days….MJO Amping Eastward spells excitment for possible pattern change to wet….
Wednesday March 28, 2018
Friday:
Models continue trend of focusing main thrust of Precipitation of an approaching “AR” for next Friday over Northern CA and Central CA. Snow levels look very high, at and above 9000 feet. So rain a good bet for the town if the models hold on to that idea for next week, The MJO is amplified in phase spaces 7 and remains amped through phase 1. So above normal temperatures are likely under the subtropical high….. highs at 8000 ft will range depending upon cloud cover between 57 and 62 degrees in Mammoth with lows in the 30s. These temps are primarily for just above the nighttime inversion..
The Madden Julian Oscillation is Amping now in phase 7, and accordingly, the Eastern Pacific Ridge is Amping as well along the west coast bringing the warm up. This upper ridge will move over CA Friday and weaken due to short wave action and peak out the warming trend with highs about 60 . Lots of high cloudiness will result over the weekend, however, temps will remain above normal. Highs in the upper 50s in Mammoth and upper 70s in Bishop. lows in the 30s at resort levels.
The MJO is forecasted to translate east over the following two weeks. For week one, that means a continuing period of warmer than normal temps according to the RIMM composites. As the MJO shifts from Phase 8 to 1 and possibly 2, the composites suggest the possibility of precipitation moving back into the Southern half of CA and the teleconnection WPO going negative with the “possibility of a blocking high near or just east of the Bering Sea. Undercutting of the westerlies with zone flow, may make it to the central west coast thereafter. This brings the possibility of an AR as well. Although It is still too soon to count on from a climate perspective, it is interesting that both ECMWF and GFS global models suggest a strong negative phase of the WPO developing (Upper Level High Pressure blocking) during the first week of April. In fact the standard deviation of normal for the -WPO is off the chart for the ECMWF and about -5 Deviation of normal for the GFS for that same time period. Their ensemble members during the 2nd half of next week support a possible AR during the time frame Thursday and Friday next week.
On another note, DWP just posted the update on the Mammoth Pass water wise. It indicated that the pass was 95% of normal for the water year ending April 1st. Again this is just telemetry and I suspect that when the manual survey is done, it will be considerably less. Nevertheless, it is certainly encouraging! It shows that the pass went from about 5 inches up until the 3rd week of February to 40.5 inches. Now that’s amazing…almost a Miracle? Again, this does not include the final manual core sampling that will likely be taken just after the first of April. Also noted that the Central Sierra was 70% of normal to date with about 16 inches of water eq. (Quite a difference). I feel that the main point here, is that Mammoth Pass possibly picked up the lions-share of the last AR event in California.
Enjoy the great weather over the coming days with spring conditions returning to the lower slopes…..
Get it while its cold……………..
Dr Howard and the Dweebs……………………..:-)
Current Stormy Pattern winding down as the last shoe to drop comes through Sunday….Associated with below Normal Temps through Monday…..A warming trend mid-week will Lead to beautiful Spring Weather……Miracle March in the Bag……
Saturday March 24, 2018
A lot of folks have asked me lately what is a “Miracle March”. What it is, is a colloquial term not scientific, that relates to a very dry winter followed by a wet March. There are no guidelines for this term and it has nothing to do with ending a drought, although it certainly can take the edge off one. As an example, the term Pineapple Express or Mango Express and several other such colloquial terms, now have been defined by Meteorologists as Atmospheric River’s. The term Atmospheric River is a scientific term with guidelines as to intensity; water vapor transport within a baroclinic band on a time scale. Wind speeds of greater than 12.5 meters per second in the lowest 2 kilometers; and a shape that is long and narrow, no more than 400–500 kilometers wide, and extending for thousands of kilometers, sometimes cross entire ocean basins. Recent research at Stanford has even put Category’s on the Atmospheric River like Hurricane’s, which may catch on and become mainstream at a later time.
So far this wet season, Mammoth Mt reports between 122 inches of snow and 204 inches of snow for the month of March. A bit more will come this weekend. When you consider that for all the months of the Fall and Winter through the end of February, the total was 81.5 inches. It is pretty amazing that over the Course of the winter of 2018, on the average, only 16 inches of snow fell a month! So to me, as in comparison to the rest of the winter it is a Miracle! Was this a record Miracle March?….No. The winter of 1991 totaled 176 inches at the Main Lodge. Additionally, this tally is in inches of snow fallen and not water content, which may also make a difference for comparison purposes.
Going forward:
Were approaching the end of March and weather patterns during the month of April are beginning to emerge. To begin with, the remains of the current pattern shows the cold portion of the pattern of the past several days coming through this weekend with snow showers and light accumulations. IE (1 to 6 inches) Colder than normal temperatures are expected to continue through Monday with highs in the low 30s today through Monday then moderating to the 40s by Tuesday and 50s by Thursday and Friday. Nights will be in the teens and 20s. Expect gusty winds this weekend with continued wind chills.
Longer Range:
Something to watch; The MJO is in an amplification mood. See: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncfs.shtml
The MJO Amping in this area will set up a strong (-WPO) (Blocking High pressure over the Bering Sea). Looking at both ECMWF and GFS teleconnections, it is noted that the WPO is forecasted to go strongly negative this end of this month, while the AO and NAO are only weakly negative and the PNA is weakly negative. This pattern change is a lot different from what we have experienced this winter. The past Winter has been highlighted by Meridional flow (N/S) while the upcoming pattern for early April looks more Zonal in nature across the Pacific. With the MJO moving into Phases 7, 8 then 1, look for strong amplification of the eastern pacific ridge first, leading to -WPO, then the possibility of undercutting of the westerlies during the end of March or the first week of April. This may lead itself to another west coast “AR” event around the 4th of April. With La Nina weakening, and ENSO trending neutral, this is another teleconnection that may lend a hand in its evolution. By the way, this pattern the first week of April for week 2 looks similar to what we experienced during the Winter and early Spring of 2017…..Miracle April anyone? 😉
DR Howard and the Dweebs…………………:-)
Major AR Event to pretty much Lock in a Miracle March for the High Country Mid-Week…Snow then rain then Snow for the Town of Mammoth…..
Monday March 19, 2018
9:20am Thursday:
Back edge of the AR has moved through the Bay Area and progressing east. As of 8:00AM, Mammoth Pass has picked up 3.5 inches of water EQ with another 3 inches in the bucket expected over the next 24 hours.
Colder storm off the coast of the pacific NW is digging SE and becoming negative tilt. It has picked up the southern stream trof and is the kicker that will bring in its remains tonight…The current AR is now pushing into Southern CA increasing rainfall rates there.
By early Friday AM a dry slot comes through, diminishing cloudiness and gives us a pretty nice Friday afternoon except for wind. The upstream cold core kicker trof will open and come through Northern CA Saturday night. Ahead of it will be light snowfall for our area. Amounts look lighter than my previous post. RFC has backed off and now reports .59 inches of QPF for Yosemite. Even at 15:1 that would be about 9 inches over the crest. Best guess for the Saturday storm….2 to 4 inches at 8000 feet and 4 to 7 inches over the upper elevations by late Sunday AM. Snow showers may persist for a while into Sunday afternoon but little if any accumulation is expected Sunday PM.
Longer Range shows ridging building in Mid-Week with Gusty Easterly Winds over the Mammoth Crest Tuesday into Wednesday with quite a bit of warming Wednesday into Thursday. It looks dry and warmer Tuesday through the following weekend.
It will be cold over the weekend with highs in the low to mid 30s in town and lows in the single digit and teens across the county.
The next possible stormy period will be beginning about April 5th or 6th….
Dr Howard and the Dweebs……………….:-)
9:30Am update
New guidance from the California Rivers Forecast Center shows the freezing level dropping quickly Thursday morning and that precipitation will be all snow to the lower elevations of town by Noon Thursday. If this is true then heavy snowfall can be expected to all elevations of Town Thursday afternoon. The same forecast shows between 5 and 6 inches of water EQ over Mammoth Pass between today and by Thursday night. This is in addition to the nearly an inch that has fallen so far.
Other changes; Moderate storm Saturday with up to a foot of light powder on Mammoth Mt and some 3 to 6 inches of snow in the Town of Mammoth as the freezing level lowers to 3000 feet Saturday. Light snow showers are now expected Sunday. Dry Monday…milder Tuesday….
Friday looks dry…..
The snow level in the Mammoth area will be mainly 8000 to 8500 today and up to 9000 feet for a time tonight. The snow level will come down during the day on Thursday and into Thursday night. The snow level will lower to between 6500 and 7000 by Thursday night.
Change in weekend forecast;
The models have been consistent since yesterday in deepening the northern stream trough enough to bring light snowfall to our area now….Saturday and into Sunday. Expect much colder temperatures over the weekend.
Next week look dry and milder at the moment.
Dr Howard nd the Dweebs………………:-)
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Tuesday AM:
Here is the latest…..
In summery…There is a lot of moisture coming to all of the sierra
In the Town of Mammoth there could be between two and 3 inches of water equivalent.
Over the lower elevations of town (7500 ft) I am not expecting a lot of snowfall. It will be mostly rain or rain snow mix. It may start as snow but will change to rain pretty quickly as the AR rushes in Wednesday so not much accumulation.
At elevations “Between 7500 and 8000” there could be up to a foot of sloppy wet snow.
At elevations between 8000 and 8500 there may be somewhere between 1 to 3 feet of wet snow. It is very difficult to tell whether it will be a 1.5 feet or 3 feet. You are only talking about a temperature difference of maybe 1 degree.
The main snowfall with this storm will be above 8500 feet where 3 to 6 feet is possible. The 5 to 6 feet is above 10,000 feet. (Sierra Crest)
The not so good news is that there is a large dry slot coming in behind this storm Friday and that will cut the moisture off pretty quickly Friday. So….not much influence is expected from the northern storm for Friday into Saturday night with only light snowfall expected.
What we have here in Mammoth is a weather pattern that is primarily an Atmospheric River with not much follow though with moisture from the northern branch.
It will be wet and wild the next few days!
Temperatures will be in the low to mid 40s today and mid 30s tonight…then highs in the upper 30s on Wednesday and mid 30s Wednesday night with little change in temperature for Thursday. I am expecting a freeze by Friday Morning with lows in the 20s.
Saturday there is a chance of snow showers and it looks to be a Blue Bird Day on Sunday..
Dr Howard and the Dweebs………………………..:-)
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The First major Atmospheric River event this year is shaping for Southern CA and the Southern and Central Sierra, for Mid-week. A wide swath of rich Precipitable Water will stream into Southern and Central CA beginning Tuesday night and will increase in its intensity Wednesday into Thursday. this is part of an Omega Block over the Central pacific and the eastern portion with its cut off low spinning at 140west and some 1000 west of the central coast tonight. The Duration of the event along with its intensity suggest that orographically favored areas on the west side of the southern sierra could get up to 10 inches of water from this storm. Here in the Eastern Sierra, the west side will take the brunt of the storm, squeezing some 5 to 7 inches of water over the Mammoth Crest for a good 5+ feet of snow. Snowfall amounts in town will vary greatly where the Mammoth Slopes area above 8000 feet will get a lot of snow through the period ending Saturday while the lower elevations of town get a lot of rain at times and not as much snow. So at times it will rain and at times it will snow at 7500 to 8000 feet. The Nested Grid model shows the snow level lowering into town by Thursday morning….This is Faster than predicted on Sunday Morning. We still have another 24 hours to follow its progress, as the storm is still developing…. By Thursday night, the AR should be south of the state while the colder portion of the pattern with its cold GOA low digs south into Northern CA. This will bring colder lighter snowfall to the high country, Friday and especially Friday night into Saturday.
Dr Howard and the Dweebs………………….:-)
