Dry Southwest flow is the word for the next 5 to 7 days keeping Mammoth dry with near seasonal temps……Expect cooler nights now with the drier air….CFS forecasting more wet weather ahead for CA………
Wednesday August 13, 2014
Posted at 8:00 am by Howard
An upper level ridge of high pressure will build over the Eastern Sierra while a weak baggy trof remains off shore. This will continue the dry pattern over the eastern sierra while temperatures return to more seasonal levels. High temps in Mammoth will rise to the upper 70s this weekend with lows in the 40s. Little change is expected over the next 5 to 7 days….
PS. The ECMWF model (week 2) has a Fetch of Hurricane moisture lurking off the Southern CA Coast by the end of the Month….
With a combination of weak troughing aloft, an on-shore SW flow and an upper high with an axis that is not conducive for the import of monsoonal moisture, these actions finally turn our air mass dry over the eastern sierra. This pattern may continue for a week or even longer….
Highs temps in Mammoth will be in the low 70s the next few days then rise to the mid to upper 70s this weekend.
Overnight lows will range in the mid 30s to low 40s depending upon wind. Winds will occasionally gust up to 30MPH here locally with more moderate winds to 50mph over the crest today and tonight.
Overall…..It is Eastern Sierra Weather at its best!
Thoughts about this Summer so Far…
Lots of folks like to try to tie past events to future weather or climate events…. Like a wet summer precedes a wet Winter or a dry and windy summer precedes a wet winter. Or pinecones clustering at the top of pine trees in Summer precedes a wet winter.
The facts show that all of these observations can be explained by what has already happened. Not a forecast for future events.
Example: If one goes outside in Mammoth today and looks at the local pine trees. There is difficulty finding pinecones at all! That is because the trees are in survival mode with the three-year drought. This will have nothing to do with what the upcoming winter will be like precip wise.
Heavy clustering of Pinecones in the Summer is a reaction to past years of normal to above normal snowfall.
Another observation: This has been one of the wettest Summers for the Eastern Sierra in recent memory. Does that mean that the winter will be wet? No… The wet Summer is directly related to the exceptionally strong Kelvin Wave that traveled from the Indian Ocean last winter to the Western Pacific and finally washed up upon the Central American coast late last Spring. The warm water underneath the surface was forced to rise and then was squeezed north and south by the continent. The northern portion of the squeeze pushed warm water as far north as over much of the California coastline. SSTA’s in the Sea of Cortez was recorded showing high temps well into the 90s! SST’s along the Southern CA coast were up to the mid to upper 70s! All this heat and humidity and the “shorter” June Gloom season over Southern CA was caused to a great extent from that giant Kelvin Wave. A big part of this years California Thunderstorm Equation and was a result to a great degree to the same Kelvin Wave that was actually initiated very early this calendar year. To my knowledge, no one forecasted a wet Summer for CA in the early to mid spring with record rains in the San Gabriel Mts. However, the CFS (Climate Forecast System) did forecast last June, precipitation departures from normal of over 200% over Mono County for July! The Dweebs here did put that into an interseasonal outlook early this Summer.
Fall type weather is settling into the Arctic now. The upper jet is gaining strength and tropical storm action over the eastern pacific is increasing. This is typical by mid August. The “Dog Days” of Summer are over……. From what I see in the extended outlook…The Eastern Sierra Monsoon Season of Anomalous Easterly flow from AZ is over…… However, with that said, in that it is expected to be a bit above normal in temps for the next two weeks, there is always the possibility of high based, isolated air mass type thunderstorms action over the Sierra.
OK…the Dweebs used the CFS for the Summer Precipitation outlook back last June and it accurately forecasted a wetter than normal July. Here is what it says for late August thru mid September. It says that between the last full week of August and the 1st half of September, precipitation will range from +200% to +250% as a departure from normal. However, the clustering is not from AZ, rather from the south-south west. Thus it suggests significant moisture from a tropical storm or two getting entrained ahead of eastern pacific trofs during that time frame.
This is the direction of where the eyes of the Dweebs will be focused over the remaining weeks of Summer.