A Fair Weather Upper Ridge develops by Mid Week….Expect an end to the Windy Weather for a 5 day period….Upper Jet Makes a return to Northern CA by Sunday Night……The forecast for Mammoth includes a dry period beginning Tuesday through the end of this week….
Monday March 14, 2016
Posted at 9:01 am by Howard
As the East Asian Jet retreats….strong height rises continue to be expected this week for California, as the upper jet lifts north into Canada by Mid-Week. Upper level winds will be very light by Wednesday and subsidence will warm daytime highs over Mammoth to near 60 by Saturday. By Sunday, the pattern becomes a bit progressive again and the upper jet makes a return to the NW coast for more upper level wind next Sunday PM into the following Monday a full week away. Looking at the week 2 progs, the next weather system arrives next Sunday night into the following Monday. That system is targeted mainly to the north of us. However, we may get some showers. The main message this morning according to the 500mb ensembles from both the ECMWF and the GFS is that a fair weather ridge will remain over the central west coast more often than not……Well into the end of March. However with that said, the deterministic 06z run of the GFS was much more encouraging for more precip with a specific storm the last week of March.
From a Climo point of view, we are getting into that time of the year where the models become more fickle and are not as reliable during the week 2 time frame….
By the end of March and beginning of April, the upper jet is in a weakening process as the days are longer and polar nights much shorter…..
”Dr Howard and the Dweebs”…………………….:-)
Friday March 11, 2016
Posted at 7:38 am by Howard
Changes in the weather pattern across the far eastern pacific and downstream are becoming less conducive for storminess over the next week. The East Asian Upper Jet stream is weakening as the main area of tropical forcing along the equator weakens and redevelops over the Indian ocean.
The immediate effects in the next two weather systems headed for the Sierra are:
- The Splitting of the Friday/Night storm due to a shorter wave length created by the upper low now lifting into Texas.
- This will have the effect of weakening it to where most of the precipitation for our area will fall on Mammoth MT or the Sierra Crest…….With a lot of shadowing as you go east.
- Snowfall estimates for Mammoth Mt are about 7 to 14 inches by Saturday AM; (3 to 7 in town)
The next and last in the series of storms will move into the sierra after midnight Saturday night with the remains of it moving out Tuesday AM. This system does not dig as much or have the depth that the models showed earlier in the week. Again, this is because of the weakening and retraction of the earlier extension of the *EAJ. With both of these storms, there will be a lot of wind. The snowfall forecasts for the Sunday through Monday Night look like more in the 1 to 2+ foot range now. So the 3 to 5 feet that was touted two days ago is off the table and more likely 2 to 3+ feet over the upper elevations between this Friday and Tuesday AM. The Town of Mammoth should get between 3 to 7 inches from the Friday/Night Storm and 6 to 12+ from the Sunday Through Tuesday AM system.
Wind: The 2nd weather system coming in later Saturday has a nasty West NW upper jet. So it will be a windy one…right on into Monday….
With the East Asian Jet continuing to retract, a full latitude fair weather ridge is probably going to develop over the far eastern pacific later next week. However…..The pattern becomes progressive again by the end of next week or beginning of the next as both the ECMWF and the GFS has another series of storms headed for California.
Last nights ECMWF brings a storm into the west coast on Sunday while the new 12Z GFS this morning shows it more like Monday. However, using the Hovmoller method, there isn’t any Surface Cyclogenesis out at 140E (off the coast of Japan), until Friday night the 18th…..which via the Hovmoller method, would propagate the short wave energy through our state Tuesday night the 22nd. So The Dweebs are not sure about what the models are seeing for a Sunday or Monday storm. It may be delayed a day or two. Stay Tuned on this one……More later on the long range next week…..
*EAJ = East Asian Jet
Dr Howard and the Dweebs…………………..:-)
Mammoth Mt picked up another 8 inches over the past 24 hours…a nice break today with unsettled weather returning late tonight and into early Wednesday…..Another Major Storm Expected by the end of this week….Storm Door to Close During the 2nd half of next week….
Tuesday March 8, 2016
Posted at 9:57 am by Howard
All forecast models are back peddling a bit on the QPF between Today and next Tuesday indicating about a 4 inch Bull’s-eye over Mammoth. That means that we could see between 3 AND 4 FEET OF SNOW BY NEXT Tuesday.
The AR forecasted for early next week looks much weaker in the models today.
That appears to be the end of this storm cycle as the upper jet lifts back to the north. However,. Winter is not done yet and The Dweebs expect that the last week of the month of March to be quite active with more snowfall……
Skies dawned clear this morning after an unsettled day Monday. A nice short wave ridge builds in today with milder temps. The ridge is dirty and so high clouds will return by Noon. Gusty winds will increase this afternoon into tonight. Highs today in town near 40. Low of 25.
Upper pattern will remain progressive through next Tuesday with a series of weather systems. The highlights are:
- Light over running precipitation late tonight through Wednesday AM. Light snowfall is expected over Mammoth Mt. (1 to 3 inches)
- Winds will begin to ramp back up later this afternoon over the upper elevations into tonight.
- It will remain breezy to windy over the upper elevations beginning later today through Sunday.
- The next storm will move in Thursday Night and will end early Saturday. That system had been showing signs of splitting according to the GFS over CA. The ECMWF model has been more consolidated all along and now the GFS is showing more consolidation with the “Upper Trof” as well with this mornings run. This trend is more favorable for strong UVM over the Sierra Friday AM. Additionally, the new 12Z guidance is showing the front left quad of the upper jet favoring the Central Sierra at 12Z Friday AM.
- Although the Jury is still out on snowfall amounts by Early Saturday AM, it seems that a foot of snow or better over Mammoth Mt is reasonable, at this point in time.
- After the storm moves out early AM Saturday, it may actually be a decent day with wind over the upper elevations but little or no snowfall. The EC shows the potential for some nice wave clouds in the AM for Early AM photo shoots.
- By later Saturday afternoon the clouds increase with the wind, as the Last in the series of deep upper lows approaches the west coast. The system has an impressive upper jet that will move into Northern CA 1st, then slide south as the upper trof reloads and deepens. Several weather fronts will move through with this system Saturday night into Tuesday AM. The ECMWF has a nice atmospheric river associated with the strongest upper jet Sunday night through Monday AM. The Dweebs are expecting 4 to 5 feet over the upper elevations during the period “Saturday night through Tuesday AM”
- There will be a long break in the storminess by Mid-Week next week as the upper pattern stagnates as a result of the EAJ receding. The GFS develops a full latitude ridge over the Eastern Pacific later next week with just a hint of a break through of the westerlies by weeks end. The ECMWF is not as bullish with 500mb higher heights, as well as the upper jet remaining well north week 2. Looking at the MJO and its composites, the MJO is pretty weak the next few weeks cruising through Phases 3 and 4 then strengthening in phase 5. However, the MJO is destructively interfering with the El Nino base state next week. That will assist in supporting the pattern change for the week two period….To go dry along much of the west coast. With the return of convection north of AU….the SOI has gone positive. This may also aid in a quicker weakening of ENSO base state in the coming 4 weeks as well..
- The Dweebs at this point are in agreement with the ECMWF and believe that the end of this particular Storm Cycle associated with moisture leaden storms from the pacific will be ending by the middle of next week.
Dr Howard and the Dweebs…………………………..:-)