Monsoon III to make appearence by tonight with lots of mid level cloudiness….Moistening to continue through Monday….With Best Chance of Thunderstorms during Monday PM and again later in the week……Models Backpeddeling on SW Upper flow….With Unstable Air Mass continuing into next weekend
Saturday July 26, 2014
Posted at 11:53 am by Howard
Deep moisture remains over the eastern sierra. Areas with good sun in the morning will benefit from the convection process (IE Surface heating)
While there is no significant trigger today…scattered thunder will be heard in many areas, with plenty of rain showers.
The latest guidance does show several Vort centers bubble up from the south. Thus Wednesday should be a more activate day and evening with more of a potential of localized heavy rain….
We go back to isolated coverage Thursday…..with warmer temps as well. Another surge of Moisture returns Sunday from the South….
Expect Scattered Thunderstorms each afternoon and evening through Wednesday…with local areas of heavy rain…….
Saturday AM Update:
High level moisture is streaming Northwestward from an MCC over the Central Sea of Cortez, MX. SST’s there are nearly 90F degree’s. Blow off from those storms has moved into the Southern CA Deserts with the leading edge now showing up over the Owens Valley. The Upper flow is now backing from the South over Mammoth Lakes and will veer more SE the next 24 hours. High and mid level moisture will be making a return over Mono Co over the 24 hours with much deeper moisture by Monday AM.
New 12z GFS had dew point temps in the low teens over Mono County this Morning. The model progg’s a steady increase in the Dew Point temperature the next 60 hours…so that by Monday morning the Dew Point is expected to be near 40 degrees over Mammoth. If Monday morning is mostly sunny, the odds for rain in the PM will be greater then 40% in Mammoth as the best forcing and vertical motion is that day. There will be plenty moisture around Tuesday and Wednesday. However, the dynamics are not as favorable. So Thunderstorms Tuesday, yes….but more isolated and convergence driven.
The Owens Valley is expected to have Dew Points into the low 50s by Monday evening and so it will be a pretty muggy Monday night by the valley’s standards, with nighttime lows in the upper 60s or even 70 degrees. Daytime highs will cool to the mid to upper 90s the first few days of the new week.
Tuesday through next Friday now offer a continuing threat of thunderstorms for Eastern CA……
More on the changes Monday AM……
Dr Howard and the Dweebs…………………….:-)
Currently, a weak upper low is west of Northern Baja reacting with the Continental High and Mammoth is in-between the two. This has spun up a weak 50 knot jet and is producing high clouds that is streaming through our area. This little feature will lift NE over Northern CA later today and tonight and RH will diminish at 300MB later today and tonight as this feature moves away. Tomorrow Saturday, the upper flow backs to the South later in the day and eventually SE by Sunday. This opens the door to increasing RH at 700MB (Monsoonal Flow) and so expect mid-level clouds to increase from the South later in the day Saturday with a lot more mid level moisture pushing into our area Saturday night and Sunday. It should remain dry Saturday with warmer temps because of the lack of high clouds. By Sunday, we may become over developed (Mostly Cloudy Early) and so any thunderstorms would be isolated. Further moistening will occur Sunday night into Monday and into Tuesday for a better chance of afternoon and evening TSRWS. There are a couple of VT centers that will lift through the sierra between Monday and Wednesday as well. By Friday the 1st…The upper flow begins to back to the SW and drier air begins to move back into our region. The Blues Fest will be Hot ! 😉 Quick Look at the new 12Z GFS 700 Temps….shows 15C isotherm over Mammoth during the late afternoon and Saturday afternoon. This is quite warm and will promote highs in the Mid 80s today and Saturday. 700MB moisture begins to increase later Saturday and into Sunday. 700 temps begin the fall off toward 10C by Sunday into the middle of next week. Temperatures do begin increasing again back up to 15C the following weekend. As far as the possibility of any remaining thunderstorms from mid week….it all depends upon the strength of the upper flow and its ability to flush the moisture out. The Dweebs will take a good look at that next Wednesday…… Note: +15C at 700MB with drier conditions in July and no significant cloudiness, usually gives Mammoth highs in the mid 80s……+10C = mid to upper 70s Dr Howard and the Dweebs