Slow warming trend in the forecast through Thursday…….Models are moving toward more summer troughing over the East Pac in the weeks to come…possibly opening the door to a tropical system next week….A surge of monsoon moisture coupled with moisture from Dolores is heading north into CA this weekend……
Monday July 13, 2015
Posted at 1:46 pm by Howard
Idea of any meaningful effect from Dolores are still in question this afternoon as the latest model runs keep her off shore. Stay tuned!
The Dweebs are reconsidering the idea of the Dolores effect upon Southern and Central CA. However, not from a wind or tropical storm idea…rather from a precipitation event. Both EC and GFS ensembles have been trending more in the direction of the most current deterministic runs today which does give Southern CA and Central CA rainfall, beginning as early as Saturday then on into early next week.
What we have here is a west coast long wave trof that is beginning to over stay its welcome. It has been weakening recently and is forecasted to continue in that direction the next several days. However, out over the western pacific, typhoon action is constructively phasing enough to create retrogression with the westerlies later this week. That action will redevelop the long wave trof off the west coast and is forecasted to pick up the remains of Dolores Saturday afternoon into Monday. This evenings 00z Tuesday GFS shows a double jet structure developing over South/Central CA for Saturday night and Sunday into Monday. It appears that an upper vort center (Remains of Dolores) will move on shore Saturday night with strong upper divergence at 250mb over the same. This may be akin to a strong easterly wave coming north around a ST high. but from the SW.
Of most importance, this will not be much of a tropical system, rather the remnant’s thereof, with an enhanced upper jet providing the ingredients for moisture and the possibility for a period of general rainfall over the weekend. Tropical storm Dolores will not be the story, as it will not be much by the time it reaches the Channel Islands. The real story will be the deformation and strong upper divergence from the two air masses combining to bring more rainfall for South Central CA. I.E. the upper jet spun up and the remaining VT center of Dolores.
It should not come to anyone’s surprise that it has been wetter than normal for the Central Eastern Sierra and extreme Western NV this Summer. But how much wetter than normal is the question. It may interest you that according the latest graphics from the CPC during the period 12th of May to the 10th of July, the isopleths show that precipitation was about 200% above normal here in Mammoth to as high as 500% above normal near the mountains around Hawthorne, NV. The CPC latest model runs show more anomalous rain this Summer in the coming weeks. The Dweebs will highlight where and when later this week.
The weather this week shows the upper trof over the State of CA weakening over the coming days with rising heights, bringing warmer weather into Thursday. There is a lot going on, on a hemispheric bases.
Here are some of the players.
1. The extremely strong MJO for July last week has moved into the East Pac and appears to be constructively interfering with the El Nino base state. Looking at the Rimm Phase Space today SEE: http://cawcr.gov.au/staff/mwheeler/maproom/RMM/phase.Last40days.html
It is located in mid Phase 8 defying most of the dynamic models as it remain about +1 Sigma. If this were Jan or February, we’d probably have a major Pineapple Connection going on now!
We now have western pacific tropical storms that were caused by the combination of the MJO and KV over the western pacific last week, effecting China; another that appears to be going to constructively phase with the westerly’s near Japan. The Dweeb will have to keep an eye on the West Pac, as amplification and retrogression down stream is still possible, even in July! Yes, mid July and “I am” having a real hard time saying that.
For those that are concerned about TS Dolores. She does not appear to be of a concern for the west coast through this weekend. The big question is, which short wave if any will be the one to pick her up her moisture? The longer she remains over colder waters to the north , the less she will be a problem. So what happens over the Western Pacific (West Pac) with typhoons, will have a major influence upon the west coast Long Wave Trof next week and beyond. Both of todays 12z runs show Dolores in the Eastern Pacific well over shore, weakening, with high clouds shearing off to the east into CA. However, both Global models do pick up her remains “about” mid-week, next week and give parts the west coast some rain. There are a few models that try to bring her in very early next week but I am not buying into that at this time.
Here is something to think about. When and if the remains of Dolores comes into the west coast, it may not be her moisture that is most significant, it maybe the remaining vort center that would affect the state. Less emphasis on hurricane moisture and more on the remaining dynamics. If by chance, she gets picked up by “a strong” for July short wave trof in the westerlies, which is possible next week, then her remaining moisture and upper divergence will be important to watch for. One thing is certain, a strong convective envelope from MJO in Phase 8 has moved into the Eastern Pac and modulating tropical storms now and that is expected to continue into next week.
Expect a nice week with occasional high clouds thru Thursday. Then an increase of thunderstorms this weekend… Thus, monsoon moisture and upper divergence makes a return this weekend.
Dr Howard and the Dweebs………………:-)
Thunderstorms Rumble with Marble Sized Hail Today…..Rare for July closed low making landfall over Central CA Wednesday…..More rain to Come especially Thursday then drying tend into the weekend…..MJO now at dateline moving east and weakening…..But not before Cranking up the East Pac Hurricane Season!
Tuesday July 7, 2015
Posted at 1:55 pm by Howard
Some lingering convection over Mono County brought a few showers and a Beautiful Rainbow in town.
ENSO now most likely driving the +PDO as the new update shows it strengthening again…
Weather outlook shows a slow warming trend with still the slight chance of a few isolated thunderstorms Sunday.
High temps in the low to mid 70s Sunday and Monday climbing to near 80 by Thursday….thus Summer weather returns…
Platinum Powder El Nino Update to be released Monday…
Rainfall totals have been over 1/2 inch the past 24 hours as the final shoe dropped and the main upper low came on shore late last night. Nocturnal storms developed as expected, early this morning with thunderstorms that began at about 4:30AM. The upper center is still over Central Ca today and so rain showers and isolated thunderstorm’s will be around most of the day today with snow showers above 11,200ft. However the heavy convective situation we had yesterday is not there anymore because it is both cooler with much less sunshine. Thus precipitation will be more showery in nature and although there may be some areas of heavy rain, it will be in those areas that are exposed to more sunshine today.
By tomorrow Friday will be sunnier. So although dynamical forcing will not be as strong, we will have more sunshine. Thus the likelihood of thunderstorms will increase again Friday just because of that added convective element. A drier air mass moves into our region Saturday as well as more of an upper convergent atmosphere. Shower activity will be much more isolated. Expect dry weather Sunday through a good part of next week with more seasonal temps by Wednesday.
From the CPC:
Synopsis: There is a greater than 90% chance that El Niño will continue through Northern Hemisphere winter 2015-16, and around an 80% chance it will last into early spring 2016.
Comment from the Dweebs……You can now pretty much go to the bank on this one snowfall wise with the likelihood of at least a normal to quite possibly an above normal winter…. The Dweebs will continue to follow the events and report any changes either way here at the Dweeb report. I will have a special report to my Platinum Powder email subscribers this week….. PS, if you have signed up for the Platinum Powder Alert before, please do not subscribe again. You are in the system….
Dr Howard and the Dweebs……………………….:-)
Wednesday AM: 8:30AM Update:
The National weather service has a flash flood watch for Mono County beginning at 10:00am this AM. So expect the possibility of heavy rain developing again today with small marble sized hail.
Possibly of further importance….the storms main area was over the eastern sections of town yesterday and so western sections of town did not pick up any rain. The latest HRRR model shows the storms firing up over the crest today and shifting NNE; so the back country this afternoon is more susceptible to lighting, hail and heavy rain, VS yesterday as it was mostly eastern sections of our city limits. An upper level low comes in tonight and so the rain may continue on and off all night tonight and into Thursday. The next 36 hours should be the wettest. We will begin to dry out Friday with just a chance of rain and a sight chance of rain Saturday. It will be fair, warmer and dry Sunday through Tuesday with highs back into the 70s.
Very slow moving Thunderstorms are dropping heaving rain and hail on Mammoth Lakes. Another report was that a TSRW stalled over Montgomery Pass and dumped a lot of rain today as well. Clouds will continue to build with more heavy rain possible, shifting east later this evening….
A Rare upper closed low is moving toward the central coast today. More potential for heavy rain, especially Wednesday/night through Thursday night. There is even a slight chance of a dusting at and above 11,000 feet Thursday afternoon and evening. On Thursday, it may just end up a rain event. Once this system moves east by Friday AM, drying trend to develop through the weekend. Expect warmer temps Saturday through Monday. But not until afternoon highs peak out in the upper 50s on Thursday! That’s 20 degrees below normal!
The convective envelope of MJO is shifting into the eastern pacific this week. It is likely that the eastern pacific will have a series of Hurricanes beginning around this weekend and continuing through the 3rd week of July. This is significant for the deserts and even parts of CA as the position of the continental high will most likely divert much of the moisture into AZ, NV and CA in the weeks to come. San Diego has had a very unusual late spring and Summer so far for rainfall. It’s possible they may get some more…
Dr Howard and the Dweebs…………………………….:-)
Thursday July 2, 2015
Posted at 3:32 pm by Howard
Flash Flood Watch Today: http://forecast.weather.gov/showsigwx.php?warnzone=CAZ073&warncounty=CAC051&firewxzone=CAZ273&local_place1=17 Miles ESE Bodie CA&product1=Flash+Flood+Watch&lat=38.0781&lon=-118.739#.VZgAMGfbKUk
Saturday the 4TH of July:
An upper wave moving NW along the periphery of the upper high is tracking NW along the CA/NV border. Abundant moisture and instability will combine to bring a good chance of rainfall to Mono County, Later this AM and this afternoon. Not every part of Mono County will get heavy rain. However, the areas that do get thunderstorm’s, it is possibly because of the nature of this pattern to get torrential rains and flash flooding. So if you are outdoors today, have a plan to be able to seek shelter if necessary. A flash flood watch goes into effect at 11:00am this morning and ends at 8:00PM this evening. Precipitation should end this evening until Sunday afternoon when more storms are possible. However, there does not seem to be the focusing Sunday for as much heavy rain as today.
Scattered mainly late afternoon and evening thunderstorms are expected today with an uptick in action tomorrow afternoon due to wave moving from south to north.
It will be drier and a bit cooler next week with only isolated action.
Here is an important update from the Climatic Prediction Center today:
During the past several days, an extremely strong anomalous westerly wind burst, partly caused by tropical cyclone activity, developed over the equatorial western Pacific just west of the Date Line. This feature helped contribute to a very strong Phase-7 projection on the RMM MJO index, more than three standard deviations outside the circle. Dynamical models favor further amplification of the RMM Index, followed by gradual weakening, with the ECMWF continuing to depict further eastward propagation of the intraseasonal signal, while the GFS maintains a more stationary pattern.
Two additional tropical cyclones developed over the northwestern Pacific during the past several days, both within the high confidence formation shape depicted on the 30 June GTH Outlook. Tropical Storm Linfa is currently east of the Philippines, and may make landfall over Luzon over the next several days. Tropical Depression 11W formed near 170E and 10N, and is forecast to move westward or west-northwestward while intensifying. Dynamical models do not favor additional tropical cyclogenesis over the western Pacific, so the TC formation shape was removed from the updated outlook. The enhanced precipitation shape was modified based on the latest tropical cyclone track forecasts.
The National Hurricane Center is currently monitoring two systems that have a potential to develop over the southwestern portion of the East Pacific basin during the next 5 days. Additionally, the Central Pacific Hurricane Center is monitoring a system near 140W and 10N that has a low potential for development during the next 48 hours. For the updated GTH Outlook, a broad high confidence TC formation shape encompasses all three areas of potential development. A moderate confidence TC shape was maintained south of Hawaii for Week-2, and dynamical models, the MJO, and the El Nino base state all favor new potential cyclogenesis over the eastern Pacific during Week-2.
A moist South East flow with transient areas of upper divergence will continue through the holiday weekend. With that said, a drying trend will begin Sunday and continue into next week. There is some differences on the handling of the upper low off the central coast next week. Will it come inland; cut off and provide an area of upper divergence focused only it its NE quad. Will have to see. However, it will provide a lot of drying Sunday into Monday. The NWS has isolated action for early next week with a lot less humidity. Highs in the upper 70s and low 80s, lows in the low 50s.
The Madden Julian Oscillation is off the charts at the moment for July. This may be the only time of this intensity this time of the year since the early 1980s; which coincidently was one of the biggest El Ninos. 1982/9183. SEE: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml
The system is responsible for modulating tropical convection as it moves west to east along the equator. At the moment the core of the enhanced state is located about 160E with its suppressed state over the Indian Ocean. It will be shifting east and weakening next week. Well see if there is any effect over the southern portion of the Hawaiian islands later next week. Eventually it will modulate Eastern Tropical Pacific, (East Pac) Watch out for TS Storm action moving along the Mexican coast around the middle of July.
About last night rains….
These MCVs are often missed on many initial analysis because of the scale but are extremely important in initiating new convection. and providing the upper divergence component of a conv/div couplet. Because these vort maxes appear to come and go so quickly, its is hard follow them from day to day with any continuity on the computer models. Only large scale systems such as ex-hurricane’s easterly waves and large MCSs get carried through on models from run to run with any continuity. The MCV is the most common upper level convective focus/ trigger mechanism around the periphery of the 4 corners high which are often mis-identified as moisture surges. If forecasters would just look at the SPC analysis they will see many areas of upper divergence that that cannot be resolved in the traditional synoptic scale vort analysis in many cases.
A mesoscale convective vortex (MCV) is a low-pressure center within an mesoscale convective system (MCS) that pulls winds into a circling pattern, or vortex. With a core only 30 to 60 miles (97 km) wide and 1 to 3 miles (4.8 km) deep, an MCV is often overlooked in standard weather analysis. But an MCV can take on a life of its own, persisting for up to 12 hours after its parent MCS has dissipated. This orphaned MCV will sometimes then become the seed of the next thunderstorm outbreak. An MCV that moves into tropical waters, such as the Gulf of Mexico, can serve as the nucleus for a tropical storm or hurricane.