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Archive for September, 2015
Wrapping up the Month of September and being retrospective..it has been a real warm one……Our first either inside or outside slider will make its way through Northern and Central CA Sunday…..Showers and possible snowfall is expected….
Tuesday September 29, 2015
Wednesday AM:
- The 06z GFS has a better organized but small system ejecting through Central and Northern CA. There is plenty of moisture for it to interact with. The models generate between .25 and .35 over Southern Mono County Thursday with a freezing level of 11,000 feet. In that it is convective, a snow level down to 9500 would not be unreasonable. So a few inches of snow is possible over the higher elevations Thursday. Expect clearing weather by Friday AM. High Temps will cool to the low 50s Thursday with 30s possible by morning…
2. Continuing with regards to the new model runs from last night. As indicated yesterday, the ECMWF has been pretty bullish in dropping a small compact deep closed low over California’s interior with its primary effects to be light snowfall Sunday. The system has small but chilly cold pool as indicated below in yesterdays discussion. The model’s run was pretty consistent on this.
3. It is the 06z GFS that is struggling to get a handle on the same system. Last night’s run drops the same system south over the pacific NW then as far south as Northern CA where it stalls it while it’s upper jet energy phases with an upstream upper low directly to the west. The 250UA jet prog develops an upper jet across Central CA with has implication’s for better QPF but a higher snow level, Sunday into Monday. The fact that the ECMWF drops the low south from Northern CA to about Fresno may mean that we may see a hybrid that combines the west to east upper jet of the GFS with a deepening upper low like the EC thus eventually creating a more cyclonically curved upper jet over CA with time. The snow level would end up higher but the QPF higher as well between Sunday and Monday. The screaming message here is that if you are in the back country between late Saturday night and Monday, you should prepare for the possibility of a winter storm capable of producing 6 inches to a foot above 8500 to 9K feet. This is not a forecast just some possibilities…..
Mote later….
Dr Howard and the Dweebs………………………………..:-)
Current Analysis and days 1 and 2 progs show a continuation of the moist mid and upper level flow over the Central Sierra. Even my wife Donna mentioned to me that she observed Virga over the weekend. Several spotters from the NWS Hanford reported some sprinkles Monday as well. The flow is out of the Tropics in the super heated Nino 3.4 region. Upper divergence is no doubt playing a role associated with the Positive tilt trof centered west of Northern CA that will make its way inland Thursday with a slight chance of showers. This is not a big deal, but this pattern occurring about 2 months from now would be. Current mid latitude pattern is NOT being driven by ENSO…Just mid latitude forcing…Heights are pretty high with this mid latitude upper low and so it remains pretty mild with the high temperature over Mammoth Lakes Monday at 70. By the way…Fall colors are in full spectrum at elevations above 9000 to 10,000. They are coming on over the lower elevations between 7200 and 9000k as well. However, we are still a good week or two before they really are going strong over Mammoth.
Looking ahead:
The Euro has been toying the idea of an outside slider for CA the past several days and is holding on to the idea today. The GFS which does not have quite the resolution has been toying with the idea the past several day on and off. This mornings 12Z GFS run showed an inside slider type system making is way down from the Eastern Gulf of AK
Here are some note worthy’s:
- 12z Tuesday GFS 500MB temps over Mammoth Sunday Evening -15C
- 12Z GFS 700MB temps over Mammoth Sunday evening +2.5C
- ECMWF 500MB temps over Mammoth Sunday Evening -19C and -2C at 700mb.
- This is a big difference and a big deal for the North Central Sierra Sunday morning! The current track of the ECMWF is more west! The QPF has gone Hog Wild with over 2 inches of precip for areas like Amador County as they are in the NE quad of the upper low. If this system takes a track further south and west, it will be a big deal for Mammoth Lakes and Tioga Pass as well. As it is now, we could get a few inches of snow above 8,000 feet “IF” this model verifies! It is too soon to be sure through…stay tuned….
Comments:
The positive SSTA’s along the west coast continue to be impressive. No doubt they will affect the over lying atmosphere Diabatically. Once the Deserts cool off later in October, it will be interesting to see how the west coast ridge sets up again and how the blocking will be with the RRR. This may delay the rainy season. Well See….
Upper High remains anchored over the Desert Southwest and will hold off the Eastern Pacific Trof at least through Tuesday….Above normal Temps following suite….El Nino Strengthening again….
Friday September 25, 2015
High temperature records will fall today over the Owens Valley with a high forecasted of 96 for Bishop breaking the previous record of 95 set back in 2010. An upper high is located over the Colorado River today along the CA/AZ border with very warm temps resulting. This upper high is likely to meander over the Desert SW until about the 1st of October when it is forecasted to shift to Texas. At that time, there is a chance that at least a weak long wave trof will set up over the eastern pacific by next weekend for some cooler weather. For the time being…any storminess from the Gulf of AK will take a back seat and give way to the possibility for moisture moving north from out of the tropics into CA in October…. Daytime highs in Mammoth will continue in the 70s, through at least Monday, with lows in the 40s. Expect light zephyr breezes… These will strengthen a bit by Mid Week.
El Nino:
I will have a more formal update in the Nino 4 update for the Platinum Powder subscriber’s in early October.
Here is a short update;
Sea surface temperatures in the tropical Eastern Pacific have risen further this past week to 2.3C in the Niño 3.4 region. These SSTA indicators are showing levels not seen since the 1997–98 El Niño. The 30-day SOI to 25 September is -16.57 and the 90-day SOI is -16.71. The snap shot for todays contribution to the SOI is hefty -30.96. So the gradient between Darwin and Tahiti is growing stronger again! The more negative the SOI is, the greater the likely hood of westerly wind bursts along with even weaker trades in this region. Currently there is another strong Kelvin Wave “that is” in the process of recharging the subsurface Nino Reservoir. Watch and track the Climate Forecast system, CFS v2 at http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst
Look at the Nino SSTAs Monthly, and track the E-3, 3.4 region. It is currently 2.4C. Odds are good, that there will be a boost in this induce up to and possibly beyond 2.5C in the coming weeks because of the KV recharge. Additionally, click on the following link that shows the development of the Kelvin Wave. Compare the latest frame with the previous. You can see a weakening of the previous frame with the warmest body of water splitting…then combining again as the new surge of warmth from the KV brings another shot of warmth to the Static KV. SEE: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml (this may require a good color monitor to see the difference in the isotherms)
Indian Ocean SSTs are continuing to have a strong influence on Australian climate. Above-average SSTs exist for nearly all of the Indian Ocean, with sea surface temperatures in the southern Indian Ocean the highest on record for winter. Recent developments across the tropical Indian Ocean show a positive Indian Ocean Dipole (IOD) pattern. The IOD index is currently at +1.1°C which is the highest weekly value since the very strong positive IOD event of 2006. Four of the five international models surveyed indicate a positive IOD is likely for the next two to three months. The IOD pattern usually dissipates as the monsoon moves south in late November or early December.
Dr Howard and the Dweebs………………………………………….:-)
Above Normal Temps likely now through Friday as Forecast models delay the arrival of Gulf of AK Trof…..Expect high temps in Mammoth to remain the 70s through Friday…..
Monday September 21, 2015
Wednesday:
Latest guidance suggests that little will change weather-wise through at least Friday. There may be a little cooling by the end of this weekend. Further cooling is expected Monday and Tuesday. It will be dry through Sunday with stronger zephyr breezes Sunday.
Other thoughts…..
Winter of 97/98:
There was only one significant storm around October 10th. A Winter pattern did not arrive until November with the lifts opening in November. Why is this significant? Because the +PDO is similarly strong today as it was then. Remember that a strong +PDO (Warm Water along the entire North America coast line)…Sets up the Strong Ridge Pattern Di-adiabatically.
The El Nino effect will over ride it later in the Fall.
IE; Oct maybe quite warm and dry “overall” through month’s end.
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Forecast models are in good agreement this evening in keeping our area warm and dry through Friday. This is a change that developed about 24 to 36 hours ago delaying the arrival of a Gulf of AK trof until at least early next week. Beyond this weekend, there is model difference’s on whether to progress the trof into CA (ECMWF) or split it offshore (GFSX). All models are in agreement in developing cooling and breezy conditions by Sunday/Monday. In the meantime enjoy the last day of Summer Tuesday, as the Equinox arrives while your asleep early Wednesday morning at 1:21 AM.
Dr Howard and the Dweebs
