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Archive for August, 2012
Rapid Air Mass Modification Overnight…sets the stage for the possibility of Showers and Thunder today……Best Chance Friday PM With The Aid of the Upper Jet……Fair Saturday PM and Sunday…..
Thursday August 30, 2012
Our Air Mass locally juiced rapidly the past 24 hours with the dew-point going from the teens yesterday morning to a DP of 40F this Am. That’s fast! Rain showers were reported over the Owens Valley this morning and near Mammoth Mt as a beautiful rainbow developed at sunrise. The lower levels are now primed……and with additional moisture advection today, no doubt there will be some rain and possible thunder. The moisture is being drawn up between an off shore trof to the the NW and the upper high over the desert SW. Monsoon moisture is combining with the moisture from Hurricane Elaina for an extra boost. Although the NWS has isolated TSRWs today and tonight…..The 12z Thur WRF forecast guidance shows a 50 knot upper jet moving into Central Ca late Friday morning…thus providing extra lift Friday and into the evening for the best chance of rain and thunder.
After the possibility of showers and thunder Saturday morning…the upper trof moves through and effectively pinches off the moisture feed from Elaina by the afternoon. So Saturday PM through Sunday PM are expected to be dry. The moisture “may” surge back Later Monday into Tuesday for another round of precipitation. The outlook for early next week is clouded; (no pun intended) as the ECMWF and GFS models are at odds with the track of Elaina early next week.
Stay tuned…………………………….:-)
Dr Howard and the Dweebs…………………………………………….:-)
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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.
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
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.
The Dweeber…………………………:-)
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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.
Warm…Breezy…Dry Weather to Continue Through Weeks end, with the Coolest Day Saturday……Some Old Hurricane Debris May End Up Over Central Ca About the 4th…..
Tuesday August 28, 2012
Latest guidance through the last few days of August shows the weather in Mammoth ending on a warmer then normal note. Highs at 8000ft should continue in the mid 70s. It will be exceptionally dry and quite breezy as well. The 12z GFS has heights at or above 588DM through 12z Wednesday then lowering a bit south of 582Dm by Saturday with the possibility of a dry cool front coming through during the day. So Saturday will be a breezy one with high cloudiness and possibly some Alto Cu as well. The High temps may cool to near or slightly below 70 at the village. Overall, a nice late Summer weekend with near seasonal temps, except Saturday. Lows Sunday Am in the 30s.
This is the time of year the climatically we could get some dying Tropical storm moisture coming up from the south or SSW. There are currently TS’s over the eastern tropical pacific. One the will move NW off the Baja coast later this week. Some times we can get showers from these if conditions are right.
Looking at the EURO for the next 10 days. The trend for above normal temps is certainly there through the end of the 1st week of September. So locals enjoy!!! To bad that most of the festivities will be over after Labor Day. If you believe in the CFS 2 experimental charts, somewhat above normal temps will continue more often then not….right on through a good part of September!! That means that high temps will be mostly in the low 70s for the month of September.
See: TEMPS http://www.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20120827.NAsfcT.gif
500MB Anomalies http://www.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20120827.z500.gif
By popular demand……My 1st best guess
Some very early thoughts about the upcoming winter:
1. CFS 2 model continues to back peddle on the strength of EL Nino indicating that by Winter it may actually end up either a weak El Nino or a La Nada Winter.
See: Latest CFS #2 : http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/nino34Mon.gif
Check out Precip Anomalies: http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/nino34Mon.gif
Model says Feb, March and April best precip months? Keep In mind that this is an experimental model.
2. What about the MJO? That is the maverick that could make all the difference this Winter as it has an notably stronger effect odds wise, during Weak El Ninos…La Nada’s and Weak La Nina’s, which this winter will most likely be. IE. there may be relatively short periods of intense precipitation over the Sierra this mid to late Winter.
3. The QBO is currently in its Easterly Phase for about the last 12 months, typically weakening the build up of cold air over the Eastern half of Canada last winter. That will change with the oscillation flipping back to westerly by years end or next winter. (More favorable for blocking pattern with import of Arctic Air 1st over the west by late Fall, then via the Great Lakes about January.
4. The PDO remains negative…in the cold phase.
5. And because of all the warm SSTA’s around Greenland the NAO will be more likely negative leading to more blocking and meridional flow (IE North-South near or around the Davis Straights. That is contrary to last winter. So it will tend to be a colder winter east of the divide.
6. There is A LOT! of warm water piling up in the NW pacific with the warm pool north of Hawaii appearing to redevelop further west. This will re-inforce the -PDO with time I believe. So the -SSTA’s over the Eastern Pacific may actually grow stronger again later this year.
The Dweebs at this point are not particularly enthused about an El Nino winter for Ca. The Split Flow pattern with the enhanced Subtropical jet normally associated with El Nino may be quite incipient and Maladroit in behavior.
My gut feeling is that at this point, the winter looks wetter then last, over all; near or a bit below average precip which is usually a good winter for the Sierra, depending upon how early the storms hit.
Will Update in October or sooner if warranted.
PS… Whether a weatherman is right or wrong with a long range forecast…becasue of so many variables, any person can be right, for all the wrong reasons…….
The Dweeber…………………….:-)
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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.
