A Fire Weather Watch is Hoisted for the Sierra of Mono County because of the possibility of Dry Lightening Saturday afternoon through Sunday evening…..Wetter Storms are possible Later Sunday afternoon…..MJO is Amping as it goes into the Western Pacific….There will be a pattern change due to this action the week following July Fourth…But it may not effect the far southwest.
Saturday June 27, 2015
Posted at 10:39 am by Howard
A few sprinkles occurred yesterday afternoon in Mammoth Lakes. The most important thing that happened was that air mass modification occurred, as evidenced by 1. Dew points have risen from the mid 30s yesterday to the mid 40s this AM and Precipitable water has jumped up in our area up to about 3/4 of an inch. Looking at the SPC this AM, there is an 850MB-250MB convergence/divergence couplet over the Northern Owens Valley at this time. Also, radar is showing light precipitation over the Northern Owens Valley. This may not be reaching the ground yet. The HRRR rapid refresh model has rainfall for our area developing later this morning and increasing this afternoon. Thunderstorms and rain showers, some of which may be locally heavy at times are possible later this afternoon. High temps will be cooler today with upper 70s more likely than 80s. The fetch of monsoon moisture along with the combination of air mass modification and (couplet’s of upper divergence and surface convergence) will continue through tomorrow, mainly during the afternoon and evening hours. There may be a break Tuesday according to the new 12z Sunday WRF model….
As previously mentioned in the past two discussion’s…. MJO induced retrogression will occur later next week.
1. The First change that will happen is that the continental high will get pulled west over North Central CA and so expect another heat wave to develop this coming Wednesday into Friday. Highs may reach into the upper 80s in Mammoth Lakes by Thursday/Friday. In Bishop between 105 and 109 by Thursday thru Saturday. With the core of the upper high so close to us, daytime convection may be capped…will have wait to see.
By the way, Bishop broke another high temperature record Saturday of 106 breaking the old record of 105 set back in 2013. One more thing….There were 5 days in a row in 2013, between 6-27-2013 and 7-1-2013 that were records for Bishop. Although the next few day will be a bit cooler due to the increase in monsoon moisture, it may still remain in the low 100s. However, by Thursday, highs will be near record levels again.
Back to retrogression of the long wave upper ridge; this change is forecasted by all global models out to 145 west by early the following week. The models are struggling with the strength of the Continental High in its western location….. If the upper high remains strong enough, it will continue to be located west of the 4 corners area. If the upper trof is stronger as it digs south the continental high will be displaced east of the four corners area. The latter would result in a long wave trof off the west coast later the following week. If the latter happened…A dry SW flow would develop leading to a dry breezy pattern, for the Central Sierra with temps a bit cooler like upper 70s. If the upper southwest high wins out, then we’ll stay very warm with the chance of TSRWs through the period. Will update on this next week.
The only other concern is that the MJOs convective envelope will be well established in the eastern tropical pacific by the Fourth of July and that following week. It will no doubt be busy modulating tropical convection as it “Constructively Interferes” with the El Nino Base state, the week following the 4th of July. If by chance, we do get a long wave trof that sets up in the right spot over the Eastern Pacific, it may draw up one of the tropical systems and entrain it in the upper flow. Chances are best that any of that would benefit the desert southwest more than Southern CA, but stranger things have happened in the past. It is important to note that the MJO that is currently strengthening in Phase 6 is possibly in record territory for July with a sigma of close to +4 according to the ECMM. That is nearly at the end of the scale as a deviation from normal. What this may also mean is for the possibility of another strong westerly wind burst along the equator, over the western or central pacific. Can you imagine injecting more warm water into the Nino Basin 150 Meters under the surface that is already +5C to +6C?
Like the Dweebs said earlier….This is getting very scary! 😈
In the meantime, enjoy the thunderstorms the next two days and hope that no new fire starts occur today or Monday.
Dr Howard and the Dweebs…………..:-)
Saturday AM Update:
Expect Low to mid 80s to continue at resort levels this weekend with over night lows in the low 50s….Expect the addition of high cloudiness today Saturday with scattered high based thunderstorm’s later this afternoon. This is due to the channeling of high level moisture between the continental high to the east and an upper low to the west. The upper low is forecasted to shift north along the coast through the weekend eventually being absorbed by the westerlies early next week. Through the process, there is the possibility of nocturnal convection as the models show good 250MB divergence aloft Sunday afternoon over Mono County and at night over the west side of the sierra. Should this verify another 50 miles east we would have rain Sunday night. On the topic of divergence aloft, the new 12z run of the WRF shows 250 upper divergence over Mono County later this afternoon into the early evening hours as well as Sunday afternoon into that evening. As Sunday will be more moist, that afternoon and evening seems to be the best chance of wetting rainfall. The upper flow does back a bit from the southwest Monday. Not too sure if that will do much to lessen the chance for thunder. However, it quickly backs from the SSE by this coming Tuesday/Wednesday.
Outlook: Lots going on in this El Nino Summer.
Once again the global models bring significant retrogression to the Hemi pattern going into the holiday weekend. This acts first to retrograde the continental high to over Eastern CA Thursday and Friday for hot weather, the 2nd and 3rd of July, then weakens it a bit as the long wave upper high both retrogrades and redevelops and AMPS at 145west. This action will dig a strong short wave trof along 125west to the Pacific NW. In the process it picks up a small upper low in the mid latitudes, early that following week. Although the Dweebs will have to keep a eye on this anomalous pattern for the week just following the Fourth of July Holiday, it is unlikely that this trof will make it far enough south to bring weather to the high country. This is because the Continental high is so strong and acts to block it. However, at the same time we have a very unusual set up over the western pacific with a very strong MJO developing the next 7 days. This MJO no doubt to the Dweebs, is responsible for the retrogression forecasted in the westerlies and the Pacific NW trof the 5th and 6th of July. Additionally, this MJO as expected, has assisted in a major crash in the SOI to -50 yesterday and -41 today. So effectively the crash of the SOI weakening the easterlies has created a better environment for convection over the western pacific while the MJO enhances Upper Divergence over the western pacific tropics at the same time. Expect an enhanced state for the development of major typhoon action over the western pacific the next 2 weeks. PS. With a little luck there may be another strong westerly wind burst over the next week as a result…We’ll see.
All the global models now have the development of a tropical wave moving out of the ITCZ at this time as the convective envelope of the MJO moves into that area. The forecast is for the storm to move NW toward the Northern Mariana Islands by the Fourth Of July… This typhoon by then will continue to strengthen the following week. Another Tropical Storm will follow on its heals for week two. Now if these storms constructively phase with the westerlies late week 2, we’ll have another issue to deal with along the west coast later, but that is not in the long range forecast. The storms seem to be headed for the China Mainland.
Tropical Eastern Pacific:
The Convective Envelope of the MJO will move into the tropical central and eastern pacific week 2 and into Week 3. Above medium precip is forecasted to extend as far east as 110West. Tropical storm action will be enhanced for both the central and eastern tropical pacific week 2 and 3. As mentioned earlier, this may also enhance the SW monsoon the second week of July.
Dr Howard and the Dweebs…………………….:-)