With a Persistent Upper Trof along the West Coast….Expect a dry week ahead with a Stronger Zephyr at times…..Rain out of the forecast for Mammoth through Thursday……
Monday August 3, 2015
Posted at 8:17 am by Howard
An upper trof will remain anchored along the west coast this week with a dry SW flow aloft. For the most part this will be a rainless week with only a slight chance Friday and night….High Temps will average near normal for August with highs in the mid to upper 70s then cool to the lower 70s by next weekend….Expect Nighttime lows mostly in the 40s this week. Afternoon and evening Zephyr winds will blow up to 30 MPH this week.
Dr Howard and the Dweebs……………………….:-)
Some folks have expressed concern about the CFS V2 with a drop in the index as of Late. Have no fear of that. The reservoir of anomalous warmth under the ocean and equator over the eastern tropical pacific normally goes through a process of weakening and strengthening over time. We had a weakening of the index back in early July and then a strengthening later in the month. The same process is going on now. Looking at the wave structure, the index will reflect strengthening a bit later this month. A lot of down welling has again occurred in the more west portion of the thermocline and that will ripple east and will eventually recharge the Nino Basin. Looking at the SOI this morning it is a very strong -38. So “La Machine” is working well! And…..The Walker Pump is quite weak… I will graphically point this out soon…
Here are the animated graphics for the Kelvin Waves and the Thermocline: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml
1. Note how the warm undersea KV wave shrinks up and expands; IE weakens and strengthens.
2. Note the 28C (upper isotherm) in Thermocline in the lower graphic. Looking at the animated graphic, you can clearly see the west moving waves rippling through by following the rise and fall of 28C isotherm. At the moment, it appears that there is another surge of warmth moving westward, recharging the Nino basin. This additional warmth will be reflected in the CFSv2 eventually…. PS, the SOI was a -38 yesterday, an indication of the gradient west to east (Very Strong) keeping the surface movement of water, west to east along the equator….
Additionally…A Hovmuller time section of upper ocean heat content along the EQ at 300M in (C)
http://www.cpc.ncep.noaa.gov/products/intraseasonal/heat_tlon.shtml Best to use Google Chrome as browser I have found…
Monday Night Extended Update:
The Dweebs looked at both the ECMWF and GFS Ensemble Control this evening. The weather will remain breezy on and off this week and into at least next Monday. There is now some concern for the closed low coming into CA this Friday as the new 00Z run of the Hi Res GFS T1534 is showing the upper low coming ashore near Monterey Bay this Friday. A shift south of some 30 or 40 miles would make a big difference as far as precipitation over Mammoth Lakes. More concerning is that the trend which is usually my friend in forecasting, is further south. So there is at least a chance now for some showers and isolated thunderstorms Friday the 7th. More later…..
Next week: The GFS, ESM Control moves the upper long wave Trof out Tuesday the 11th and retrogrades the continental high back over the Desert SW, for a return of the Monsoon. The ECMWF delays the warming until 13th; (The next Thursday) and then also retrogrades the Continental upper High but sets it up further south over AZ and NW. This give us a warm up without the Monsoon as the upper flow remains SW and dry.
What does this mean? It means that we’ll likely warm up for by the 12th or 13th. The issue of Thunderstorms is still a question. After looking at the actual Ensembles of both global models, my personal take on it is based somewhat upon the Summer so far. So the likelihood of more thunder and rain showers is the best way to call it from this point in time, the 2nd half of next week. Additionally, the upper flow looks more southerly instead of southeasterly, so the pattern may not be as robust for thunderstorms unlike the last two monsoon outbreaks. Updates on all of this later this week…………