Monsoon Moisture to Remain in Place Through Friday with a Persistent Forecast of Afternoon Thunderstorms this week….Drying Begins Next Weekend…….
Monday August 13, 2012
Posted at 9:21 am by Howard
Quick Update Thursday AM;
Thunderstorm action was isolated in the southern Mono County area. Today the air-mass is similar, however a surge of moisture is moving NNW from SE Ca then turning NW at 36 north. It is expected to push up into Mono County tonight and continue northward through Friday and Saturday. An especially juicy surge is expected Friday into the Friday night some of which includes some of the remains of Hector now SW of Cabo San Lucus.
The NWS has isolated Thunder today Thursday, then Scattered TSRWs Friday and Friday night then Isolated Saturday and Sunday. Some of the newer guidance is suggesting that the action may continue a bit longer into the weekend.
Will update in the Morning…..
Next Week looks dry at the moment and sensibly cooler beginning about mid-week.
Wednesday Am Madness…..
The Dweebs this morning were looking for a trigger that would initate deeper convection today. Water Vapor Loop showed the old upper low off shore at about or just west of 125west/36.5N. SSE Flow over Mono County and debris clouds still in the loop from yesterdays Sierra storms mostly to the north. To the southeast, a strong MCS developed over Sonora, Mex. There was plenty of convection still occurring over the Sea of Cortez and South Central AZ as well.
At the moment….there appears to be a subtle area of dryness or some kind of dry slot over the southern San Joaquin valley then SE into SOCal that should move into Mammoth late this afternoon or this evening. (Possible VT center?) This may keep the convection going into the evening hours beyond diurnal expectations over Mono County. Otherwise the main action looks to be mostly further north today like yesterday, with the exception of that dry area in the wave loop that will arrive sometime late today. The NAM has Thursday more stable so storms will be more widely scattered.
Next big question will be what happens Friday. 12NAM has area of 70%Rh moving rapidly NW into California and moves up into the pacific NW as well. The Subtropics south of US/Mex border is loaded with Tropical moisture from a combination of Monsoon Moisture and moisture from TS Hector. This moisture moves rapidly northward through California Friday into Early Saturday before getting blown off to the east Saturday PM. Thoughts this morning about Friday range from the moisture coming in too early so that conditions become over developed with nothing much happening, to deep convection with Rain and Thunder that continues well into the night Friday.
As far as the weekend goes…..If storms do develop Saturday during mid to late morning…..they should get blown east later in the afternoon as SW flow increases with rapid drying occurs from west to east during the PM…..due to the ejection of the off shore upper trof.
Next week looks dry for the most part with highs in the 70s in Mammoth and lows in the upper 30s to mid 40s. Afternoon and evening Zephier winds will develop Saturday PM and continue into next week.
Temps over the next 5 day will range from 75 to 80 with lows near 50…then night time lows cooling well down into the 40s early next week.
Tuesday Am Update:
Heavy Showers and Thunder roared across the Mammoth area yesterday afternoon. Mammothweather.com picked up .19 hundreds yesterday while some RAWs stations in Mammoth had up to .33 hundreds.
Today lots of Monsoon moisture remains in place. However, the Cap is a bit lower today so showers may start a bit later in the day. Outlook is the same with subtle differences in the make up of the atmosphere over the Southern Mono county area. IE the little waves are hard to see in models that trigger possibilities. Overall, Terrain induced RW’s is the rule with the high elevated heat sources providing lift and pulse type storms.
Scattered showers and Isolated thunderstorms are once again in the forecast with a good 50% probability of .01 of an inch in anyone’s rain tip bucket for Mammoth Lakes.
Still keeping an eye out for the moisture remains of TS Hector over the weekend when the upper low now currently near 130W gets the boot across the Northern Sierra. It could get interesting Saturday when some of the remains of Hector get lifted over the Sierra ahead of the upper Trof that comes through to the north Later Sunday. More later………..>>>>>>
Thunderstorms continued each day over Eastern Ca this past weekend. Although there were reports from locals that some brief showers occurred….MammothWeather.com had nothing recorded in the rain tip bucket here near the Village at Mammoth. The Dweebs see no change in this pattern through Friday. However drying is expected to begin Saturday and increase Sunday, as a system moving though the Gulf of Alaska gives the boot to the off shore upper low NE into the Pacific Northwest/Northern Ca beginning this weekend. This backs the upper flow from a more SW direction. (Drier upper flow pattern). In the transition, thunderstorms will become more isolated over the Eastern Sierra and end early the following week. Daytime highs will remain about 80 degrees each day, however this is increasingly above normal as climo temps head slowly south each few days.
In the meantime…..Monsoonal moisture will continue to support showers and thunderstorms mainly during the afternoon and early evening hours. This will be mainly driven by the high elevated heat sources of the Sierra and areas of surface convergence throughout Mono County. By midweek, an upper ridge moves westward from New Mexico, so that by Wednesday night/Thursday, deeper tropical based moisture moves northward Via Baja, Ca. Any slight trigger of UVM would be sufficient to bring night time Thunder to the high country at that time. The Dweebs do see such an area of UVM. Stay Tuned…….
Next week: Beginning the 20th….
An Eastern Pacific trof will swing through the state. As the thermal trof returns to Nevada, gusty dry Zephyr winds will return to the Eastern Sierra Monday through Wednesday. This is a dry pattern with temps cooling to the mid 70s.. For the time being…that puts an end to our thunderstorm pattern. Will it redevelop again??? Stay tuned………………>>
Dr Howard and the Dweebs………………………………..:-)
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.