Cooling Trend in play as Chilly Upper Level Low over the Pacific Northwest Decends South into California Early Wednesday Morning……Light Snowfall Expected to Begin Late Wednesday AM for Mammoth Lakes…..

QPF 6:00pm Update:

No Change….

1 to 3 in town and 3 to 6 over the crest Wednesday morning through Thursday morning…..

No Surprises this morning. This mornings 12z Tuesday WRF has the path of the upper low at 500mb tracking over the western slopes of the Central Sierra by early (21z) PM Wednesday. The Upper low at 700MB at the same time is about 60 miles inland from Monterrey. UVM begins to increase over the Mammoth area around 3:00am Wednesday as “the nose” of a 140knot upper jet up over the Oregon coast stretches due south along the Northern and Central CA coast. This produces the lift necessary to begin the action. Thereafter, the upper jet begins to round the base of the upper low later in the afternoon Wednesday eventually carrying the upper low just south of Las Vegas, Nv early Thursday morning.

Moisture at 700mb increases to 50% by 12z, then 75% by 15z then 90% by 18z Wednesday morning……..Thus snow will be likely for Mammoth Lakes late Wednesday morning through the evening hours. The 90% RH pool at 700mb shifts east of Mammoth after midnight and so snow showery weather is expected to begin after midnight Wednesday night with showers diminishing through the morning hours Thursday.  Sky’s will be partly cloudy Thursday afternoon then clearing over night….  the high temperature forecast for Mammoth on Wednesday is 38 degrees.



The pattern is set up with a series of short wave dropping SE from the Gulf of AK. Subsequent short waves will be dry for the Mammoth area as Sundays short wave has the upper jet cutting SE through the Pacific Northwest then clipping NE Nevada. This system will bring some NE flow and some minor cooling along to mammoth with a period of mild off shore flow for SC. The Surface high associated with the NE Flow is way up in Montana and does not move into NV,  or a stronger Santa Ana event would develop.

As a side note, there is a more significant upper trof that is being handled differently for the global models. It bears watching. will be into the eastern pacific by about the 15 of October. The models are all over the place on that one…….anything is possible…so stay tuned for updates on that system.


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Beautiful Warm Weekend Inplay with a Cold Westside Slider on the Way……..Light Snowfall expected for Mammoth Lakes Wednesday into Thursday……

Tuesday Am Update:

QPF has settled in at between .4 and .5 .   The snowfall forecast is 1 to 3 inches in town and 3 to 5 inches in the upper elevations…..

The track of the upper center is pretty much right over the top of us now and as of late….which is an adjusted slight jog to the East.


light Snowfall will begin during the day Wednesday and end Thursday evening.


More later………………………:-)



Saturday AM Update:

Mother Nature Picking up the Tempo……

Both Global Models last night still suggesting some nice light snowfall mid-week. Speed of system will determine the amount of snowfall as the American GFS model is pretty quick to move system out of here during the day Thursday. The  ECMWF delays a bit more keeping the system far enough west to continue upslope snowfall in the high country into Thursday evening and suggests up to 3 to 5 inches in the higher elevations by Thursday night. The ECMWF is certainly the most aggressive with snowfall as it is slower. By 00z Friday the EC has the upper center over Southern NV while the GFS has it over east central Utah. Both models agree on tracking the upper low far enough west for westerly flow into the coast west of Mammoth with the upper center at 500mb along with the center at 700mb very close to Mammoth Wednesday Mid afternoon.  So the upper center will “initially” be the instability that brings precip to Mammoth Mt associated with the upper low itself rather than any prolonged westerly advective flow.  On Thursday, upslope will develop as the upper center shifts south and east with NNE flow in its wake. There is some moisture indicated at 700mb that will trail the upper low Thursday by both models. Again….There will be a period of Upslope as well, but this system is not your classic inside slider any more. Track of Cold Upper Low for Mid week still suggests a model blended 4 to 5 inches over the higher elevations and even 2 to 3 inches in town.  If you have not blown your sprinklers out yet…..this weekend would be a really good time! A lot of cold air will settle over the area Thursday with possible upper teens at night in some areas.

Retrogression is apparently in the cards in the longer range as the next significant short wave digs south further west over water.  However, a strong split in the flow is noted as it approaches the coast around the 20th.  The Dweebs will have another look at that system Tuesday AM.


Stay Tuned……The Dweebs have you covered…………………………………………………;-)


Dr Howard and the Dweebs……………………………………………..:-)

Chilly Today Warm Tamale…..Upper Ridge with Warm temperatures over the Weekend to Follow Shot of Cold Air Currently Over the High Country…….Cold Inside Slider Looming for Next Week is beginning to dig further west in subsequent model runs……Will have to Keep a Weary eye on this little Bugger!

There was some light frost this morning in the Mammoth Slopes area at elevations near 8000 ft and temperatures dropped to the low 20s here near the Village. As mentioned a few days ago, the Aspens  are coming on strong now.  Color in the high country at the 8000 foot level will peak in the next 6 to 10 days……Depending upon weather. Meaning that any excessive cold snap could turn some black with a hard freeze. Time to plan that Fall trip to Mammoth as this is one of the most peaceful and beautiful times of the year in the Sierra.

Weather wise it will be cooler than normal today with light breezes in town. High temps today will be in the upper 40s at the village with another cold one tonight in the mid 20s. Gusty NE winds will blow today over the crest only.

The weather for the weekend will be a classic warm weekend with warm days and chilly nights.  Winds will for the most part will be calm with highs on Saturday in the low 60s than upper 60s on Sunday. The GFS has the upper ridge building in with 500mb Heights in the low 590s Saturday evening and 500mb to 1000mb thicknesses into the mid 570s Sunday afternoon.   So Sunday afternoon and Monday AM will produce the warmest temps in the afternoon and early AM. For you painters, Over night lows because of mild inversions will be above freezing Monday Morning at the 8,000. Elevation. Only the coldest valleys will be down to or below freezing.

Outlook Next Week:

Last nights GFS and ECMWF both came into agreement showing a cold inside slider type short wave. The models keep the strongest jet energy just off the coast.  So as the system comes in Tuesday, winds will not be a major factor here in the high country. However, as the system digs and shifts SE…..A  NNE component develops on the back side of the upper low, creating  gusty North Winds for the upper elevations Wednesday/NGT and down through the Owens Valley. It also develops some moisture at 700mb on the systems back side for Wednesday PM. Although, both models have this system as fairly moisture starved by the time it gets here with mainly over land trajectory. The EC, develops its best 700mb moisture Wednesday PM with into Thursday night. It appears that we would  be in for some “Upslope” over the Sierra Wednesday afternoon into Thursday Night if the EC is correct. The EC also has Isopleths of QPF as high as .5 near Mammoth in the most favorable areas. So it looks like we “may be” in for some light snow Wednesday into Thursday night with highs in Mammoth in the very low 40s. If the ECMWF’s QPF is correct we could see 3 to 5 inches in the most favorable areas.  Stay tuned…..

Friday 3:30PM update:

Newer guidance is showing the upper low digging a bit more west now over the top of us Wednesday afternoon. This does not change the precip forecast but increases the odds of it.  In that the GFS is beginning to get more aggressive, any further westward track by another 100s miles or so would be a game changer in the amount of snow that would fall.  Will have to keep an eye out on this little bugger……..

Note: This is preliminary as this is the Dweebs first look at this system. Updates will adjust QPF up or down as needed.

Next update Tuesday AM or Sooner….. 


Dr Howard and the Dweebs………………………………………….:-)