Archive for September, 2012

September to end on a very warm note with October hot on it heals!….Models now back peddeling on cold system for next weekend……WX just returning to Climo….

Quick Sun AM Update:

Gorgeous Days ahead, with the heat peaking Monday into Tuesday with highs in the upper 70s! Bishop up to 93 degrees Monday/Tuesday but no records. The records for Bishop set back in the 4 day heat wave of 1980 was 95,97,95, 96 beginning September 30th and the following days into October.

Pattern highlighted by strengthening upper high over Ca as upper low retrogrades further off shore then deepens next week. Pattern becomes progressive after the following weekend. Eventually the offer shore upper low will come into California “around” the middle of the following week. When it does, there could be that dusting that folks are looking for with the coolest days since last Spring. That will be around the 7th-8th of October.  This mornings operational run of the 12z GFS suggests another small closed low splitting off from the westerlies and taking about the same route into Ca around the 15th or so. Overall…..temperatures are expected to end up above normal for the month of Oct. Cool inside slider to return temps to near seasonl value by weeks end…then further cooling expected when the upper closed low comes in abouth the middle of that week. (7th/8th)


The Dweeber…………………………………:-)



Yes…it is early Fall and mother nature has the right this time of the year to change her mind frequently…..

An anomalous strong upper high will build over the Ca and bring some of the warmest temps for early October. Highs over Mammoth may reach mid to possibly upper 70s while bishop heads for the low to mid 90s.  If that ain’t Summer weather what is? Meanwhile, as the upper ridge builds, cool air will radiate out in the longer nights and provide freezing temps to the lower valleys of Mono County each night through Tuesday AM.  Areas like Crestview will go below 30F at night.


Retrogression of the upper high and the configuration of a developing REX block off shore will keep the strong short waves from digging too far south and west. Instead, it is scenario 2 from the last post where the system will dive into the Northern Rockies and bring some wind and cooling for the high country. The Northern Rockies will receive their first winter like weather. Precipitation over Northern Ca if any, would be scant.

Upshot will be a return to Climo with highs cooling to the low to mid 60s by the following Sunday. Currently…the new 9/29/12-12z operational run of the GFS is consistent with last nights run in progressing the block to the west coast for warmer temps. Now with all that said, that upper level mid latitude low portion of the block has to come in sometime. When it does, there will probably be clouds, showers and further cooling. That should hold off now until early the 2nd week of October.

Like March and April, longer range models are not nearly as accurate as they are as compared to the November through February time frame.

The Winter forecast is still a long way off from being understood in my opinion as lots of things are changing. In the meantime, we do not get Summers and early Falls like this very often….so enjoy it while it lasts!!


The Dweeber…………………….:-)

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.

As one of the warmest Septembers comes to a close….Retrogression of the long wave may bring major change to high country weather later next week…..There will be the possibility of strong cooling with precipation and even some snow in the higher elevation by the following weekend……

While Reno is looking to break 100 year old records for the warmest September on record along with similar conditions over Eastern Ca…mother nature has been quietly planning a change to cooler…possibly wetter weather with even the chance of some snowfall in the highest elevations of the back country the following weekend.

Retrogression of the long wave ridge currently extends from West Central Canada then south over the inter-mountain west is forecasted to back up to about 140West; (1400 miles west of Mammoth) by the following weekend.

In the meantime;  as the upper ridge in the mean backs up….it will grow warmer over the high country through Tuesday.

1. There is a weak mid latitude upper low west of South Central Ca. that is pulling up some moisture from west of Baja. A 80 knot upper jet at 250mb is forecasted to spin up the next 24 hours as it moves into Northern Baja.  The front left exit region favors the Tehachapi’s and Southern Sierra with spokes of vorticity remaining west of the crest. The model’s QPF however is light and focused upon the Southern and Central Sierra this afternoon and evening.  Most instability is South and west of Mammoth.  The forecast for this afternoon and evening is for a 20% chance of showers & thunderstorms.

2. By Saturday….the upper high strengthens and caps most convection. Warmer temps will be the rule through Tuesday with highs in the mid seventies the first few days of October.

RECAP:    With the upper ridge migrating west, ridging will strengthen over the next few days with record high temps a possibility over Eastern Ca this weekend into early next week.  There has been a weak mid latitude upper low off the Ca coast, far enough west to channel a small amount of the remains of Miriam just off the Southern Ca Coast.  This mornings 12z guidance has several spokes of weak vorticity coming into the Southwest coast.  Some of that moisture as it combines with the anomalously warm temps and weak divergence to the south will help to destabilize the atmosphere and allow isolates TSRW’s to form today. As the upper ridge strengthens further, the atmosphere will “stabilize” to cap off convection for the weekend.  At the same time the upper low backs up as high pressure aloft over California puts the squeeze on the upper low westward into early next week. Temps in the meantime will range pretty much in the low 70s for the Mammoth and June area this weekend and rise to the mid 70s Monday and Tuesday. Low 90s in Bishop by Sunday.

Longer range next week:

The upper ridge should hold through October 3rd….Wednesday.  As the long wave ridge continues its retrogression…Short wave energy will begin to drop SE toward the Pacific Northwest…. “Possibly”coupling with the mid latitude upper low and drawing it northward, as cooling begins and moisture streams into California later Thursday. Thereafter, if coupling is truly in the cards…..subsequent short wave energy will deepen the upper low and move it east into California,  providing further cooling and precipitation along with a chance of the first real dusting over that weekend.   Beyond that…..indications are that warming will return for the high country with Indian Summer weather in the offering….

“Another Scenario” does not couple the upper low to the west of us, with short wave energy coming in as an inside slider, bringing just cooling and gusty winds.  Either way it’s looking significantly cooler by the following weekend.


The Dweeber………………………….:-)

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.

Beautiful Weather to continue in the High Country, with Above Normal Temps Returning This Weekend….Next sensible change in the weather expected during the first week of October……

Wednesday Am Update:


Moisture from Miriam, will be split NW/NE around the desert southwest. Most moisture will head into Texas via Sonora Mx, however the upper Subtropical upper low will pull some moisture NW off the Southern Ca Coast and will wrap into the off shore low. There is still the possibility of some of this moisture getting channeled northward along the Ca coast then inland into the Sierra about the middle of next week or just prior to the following weekend. The results would be showers and the back country’s first dusting!……so will keep an eye out for this.

In the meantime enjoy! Enjoy warming temps in Mammoth back into the low 70s by Thursday and fair WX. Night time temps will be above freezing Thursday AM in Mammoth and through the weekend….Temps in Bishop back to the low 90s by Sunday……!!!!


Some thoughts this morning…….

The El Nino Forecast continues to look weak this fall with the possibility of ENSO neutral conditions returning for most of this Winter.  It very well may be that the influence of the -PDO has some kind of dampening effect upon El Nino strength or its growth?   The phases the AO and NAO which were quite positive last winter and negative this Summer/Fall have been recently relating to a lot of Meridional flow. (N/S)  The easterly phase of the QBO that has been ongoing since last Fall 2011…..(time wise) is getting quite seasoned and a Flip to the Westerly Phase will be more likely anytime after the new year.  Most long range forecasts I have seen have been based in part by the ongoing Easterly Phase of the QBO.  IE. Strato winds moving from East to West which usually relates to a weaker Hudson Bay Low. A Westerly Phase in the QBO often times relates to a deeper Hudson Bay Low and stronger -AO and -NAO numbers during the Winter especially during the time of the flip from easterly to westerly or vice verse. So what I would expect during the winter and the current set up of the supporting warm SSTA’s throughout the Davis Straights are very large negative departures of normal in both the -NAO and -AO, not unlike the winter before last.  However, the Pacific SST set up is quite different now than it was as compared to the Winter of 2011.  Two years ago we had a strong La Nina, last year a weaker La Nina.  This Winter La Nada?    Case in point, weak El Ninos “often times” cause drier than normal winters for the interior portions of Central Ca.  With that said……ENSO +/- of 05C are notorious for stronger MJO activity.  Combining a Winter with Enhanced Meridional Flow and Strong MJO action carrying through the Western Pacific may make all the difference in being the important feature for February/March during the winter of 2012/13 in Northern and Central Ca.  The Dweebs are once again mentioning this because of the current ENSO set up over the central pacific. I am touting the possibility of a Pineapple Connection later in the Winter. The odds are higher for this during a forecast of a weakly positive ENSO State and would make the difference of a drier then normal winter with conversion to a normal or even a wetter then normal winter, water wise.  Are the Dweebs Forecasting a wet winter. No…..  However, odds wise, there is a stronger possibility of the subtropical branch of the westerlies out of the tropics reaching the west coast later next winter I believe.



Jack Frost took a quick swipe at the lower elevations of town this morning as lows were near freezing. This timely occurrence is expected by late September.  The pattern over the far west is highlighted by upper ridging building in while an area of low pressure aloft develops to our WSW. Tropical storm Miriam is headed NW but will make the turn shortly to the North then NE coming inland over Central Baja. Some debris from her may get caught up in the upper flow,  with a subtropical upper low developing to her NW over the weekend. Rainfall is expected over the desert SW from the debris. However, for Southern Mono County, there was not enough threat to put the slight chance into the forecast.  So expect a very nice warm weekend with highs in the low 70s….I.E. about 8 degrees above normal for this time of the year.

Next pattern change retrogrades the upper ridge westward to the western G of AK while the upper low that is expected to develop over the next few days remains off-shore. A sort of Rex block is likely to develop over the eastern pacific with heights remaining above climo so warmer then normal weather to continue through the end of September.

We will have to keep an eye on the fact that once the upper ridge gets west of 140west….there is always the chance that short wave energy coming over the top of the upper ridge could dive southeast into the pacific-northwest and pick up the upper low to the southwest of us bringing showers, a dusting and much cooler weather. This is not a forecast…..but something to watch out for toward the end of the first week of October.


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.