Airmass dry as a Bone…..Monsoon push into Southern Ca Now Occuring…..Most of it to remain mostly south of Mammoth….So slight chance of a shower or thunderstorm Thursday and Friday…then Dry for the Weekend……Forecast Tempo to pick up for Eleanea Next Tuesday/Wednesday….
Wednesday August 29, 2012
Posted at 10:08 am by Howard
Wednesday Am Update:
At the time of this discussion…there was a band of debris clouds…..probably Alto Cu pushing north into the Southern Sierra. I am not sure if this will make it north into Mono County but it may….
Monsoon moisture is making another run into Desert SW. It advects into Southern Ca, Nevada and Southern Sierra…then east of Mammoth to the Nevada border. So these areas will be under the gun beginning Thursday through Friday night for TSRW’s. Northern areas like the Mono County Sierra are on the northern edge. Our air-mass over Mammoth is currently bone dry with surface dew point in the teens. In fact yesterday at 3:00pm, dew points dipped below 0F. So we have a very-very dry air mass presently. No doubt it will juice up a bit the next couple of days and we will begin to experience afternoon convection. Thunderstorms? Well it is in the 20% probability class Thursday PM into Friday evening.
It will certainly be warm enough for convection with highs in the mid to upper 70s but our air mass will really have to go through some serious modification the next 2 days for that to happen. To the south, the Mountains of Inyo County and east….no doubt there will be Showers and thunder…especially Friday/Ngt. The NWS has slight chance of Thunder throughout the night Thursday for Mono County. Not sure what they are looking at. There is a weak trof coming in Late Friday night into Saturday….But SW flow should keep things dry unless storms form on the west side of us 1st.
More importantly, is the forecast revolving around the remains of dying Hurricane Ileana early next week. The new 12 z GFS shows it coming NW several hundred miles west of Baja….then swinging NE into Northern Ca by Mid week next week. It is interesting to note that a weak circulation center at 700mb stays intact as it moves north…well west of the California coast late Monday night into Tuesday. The 50% RH line pushes north well north during the day Tuesday through Mono County, and there will be plenty of heat for convection that afternoon. Additionally the Rt Rear Entry area of a 50knot upper jet at 300mb is over Mammoth Lakes. So you have UVM as well. The Dweebs will watch this the next few days but thinking at this time is that some rain or rain showers is in the offering Tuesday afternoon and possibly into the night as well….Showers may linger into Wednesday.
Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.