Mammoth Weather

2/4/2023 Saturday AM Update

For our weekend storm, it appears that most recent model runs have continued the trend of Beefing Up the snowfall predictions. Here in Mammoth, a good two feet is now expected above 10,000 feet and over a foot in town by Sunday Evening.  The storm is moving in sooner today with the Winter Storm Warning beginning now at 7:00PM instead of 10:00PM. The good news is that the storm will exit sooner by late Sunday afternoon instead of Sunday Night. Heaviest snowfall will be between Midnight Tonight and Sunrise Sunday AM. Expect snowfall to continue throughout the afternoon Sunday. For today Saturday, expect winds to ramp up sooner and throughout the day.

Although a dry day is expected Monday, it will be windy over the Sierra Crest in the morning and quite breezy over the lower elevations out of the North, then shifting from the NE in the afternoon. That favors the Sierra Crest as far as strong winds with diminishing wind for the lower slopes during the day as again, the upper flow becomes NE.  Tuesday will dawn with calm winds and it will certainly be a Blue Bird Morning. A storm moving through the Pacific NW will kick up moderate wind again during Tuesday afternoon.  Tuesday’s high will near 40.

Strong Short Wave Ridging is expected Wednesday afternoon through Friday afternoon. So winds will be greatly diminished during this period with daytime highs 45 to 50 in Mammoth!  Some excellent Blue Bird Weather both Thursday and Friday!

This  mornings 12Z GFS shows the next Storm System digging south, west of 125W Friday Night and Saturday. Wind’s will come up along the Eastern Sierra Saturday afternoon.  The GFS has this trough almost cutting off Saturday afternoon while the ECMWF is showing a cut off low off shore. The GFS model shows the upper Jet favoring the Southern Sierra and Southern CA for mainly light snowfall for Mammoth Sunday night into Monday.

The European model really slows down the storm as the Upper Trof becomes cut off from the westerlies, Saturday afternoon into Sunday night. It appear to be waiting for the upstream kicker short wave to couple with. This delays the storm for California until Monday.

As a side note, the upstream kicker dives into the back side of the cutoff, and lifts it NNE into California,  Monday afternoon the 13th into the 14th. This scenario focuses the most moisture and vertical motion into the Central Sierra whereby Mammoth becomes more of the Bullseye for this storm. Additionally, well have to see what the Kicker System does beyond that time frame.  Stay Tuned!  The models should get into better agreement over the next few days….:-) “It can go one way or the other”

The Dweeber……………………….:-)

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It was a cloudy and breezy Friday morning as a weakening storm brushed the Mono County High Country.  Tomorrow morning looks pretty nice until the winds come up in the afternoon ahead of the next storm system that may bring snowfall as early as Saturday Night. The NWS has a Winter Storm Watch for this Late Saturday Night.

A moderate snow storm is expected through out the day Sunday before its exit Sunday night. This looks to be the last significant storm until weeks end.  Snowfall amounts will be in the 15 to 20 inches range on Mammoth Mt while amounts in town look to be around a foot. Snow to water ratio will average 10:1 on Mammoth Mt. (Average)

Highs on Sunday are expected in the low 30s in town.

A strong ridge ridge of high pressure builds in Tuesday and holds through possibly Friday next week as shown on this mornings 12Z GFS deterministic run. If this works out….This ridge should send high temperature’s warmer than any day so far this year. This means high temperatures possibly into the 50s in Mammoth later next week.

There is a possible pattern change to more of an active one, developing next Saturday with clouds and wind.  Superbowl Sunday may be Snowy… Sorry for the folks that have to plow during a Snowstorm. Lets hope the weather maps change!!!!

Beyond that weekend, there is MJO support for a week of weather to deal with!!  See Below: 

As you can see, there is a bias toward the return of storminess beginning about the middle of February for about 7 to 10 days. This is based upon the lag composites, using the GFS model; MJO RMM Phase Space, using late phase 6 into phase 7 for February. 

For Mono County, it will be one cold night tonight. (CPK) Continental Polar that has been modified a bit has moved into Mono County last night. This will result in high temps in the mid teens today and lows near zero tonight.

The weather system that brought 4 inches of Platinum Powder yesterday was off the coast of Southern California this morning. Short Wave ridging in its rear will settle the cold into the high elevation valleys of Mono County tonight for Classic “Three Dog Night” conditions!  Expect lows tonight between -20F and -27F in the coldest valleys such as Long Valley and Bridgeport Valley.

Our Old Friend “The Hudson Bay Low” will greatly limit precipitation for the Friday storm as its position over Hudson Bay (PV) keeps strong ridging over the far west.  That will weaken the Friday system and so don’t expect much more than a dusting or and inch or two at the most after midnight Thursday night into Friday AM.   By Friday, the Hudson Bay (PV) shifts rapidly east so that by Saturday AM, it is off the coast and out over the Atlantic. This opens the storm door for the Sunday Morning system. That storm looks to be with us into Monday morning. At the moment, it appears to be a storm of moderate strength, capable of about 12 to 18 inches over the crest with roughly 1/2 of that in town by Monday the 6th. The weather may turn colder after that storm with the next system more of a slider. As a note, later that week the Eastern Pacific Ridge is flat, north of Hawaii. So we are not out of the woods yet for other storms in the future. Just need some amplification to get it all going again!

Dr Howard ad the Dweebs………………………:-)

1/27/2023

10:00AM

This mornings global model runs show some interesting changes for the first half of the month of February.  Here is what the Dweebs see.

1. At this time, the Hudson Bay Low (Canadian Polar Vortex) has become very strong and deep. It is tied in with the strong, highly amplified ridge over the Eastern Pacific. This pattern is very common during La Nina winters where-by it is colder than normal in the west and central and at times eastern portions of the US. This pattern is a blocky pattern over the Eastern Pacific keeping out any big storms from affecting the central west coast. The system for Sunday into early Monday is classic!  Cold system with light snowfall and upslope as well.
2. So here is the upshot of this AMs post in getting all the ducks lined up again!
3. The Hudson Bay Vortex is forecasted to begin progressing east, just before Ground Hogs Day Thursday.  The Dweeb’s are not sure why as the Eastern Pacific upper block actually starts to break down 1st over the Eastern Pacific, this upcoming Monday.  This eastward shift of the Vortex opens the wave length between the eastward shifted Vortex near Newfoundland and the retrograding high over the Central Pacific.
4. Additionally, the Atlantic Ridge, east of Iceland is beneficially located. This positive height anomaly is also suggestive of a pattern that is progressive as well.
5. The next storm track does not appear to have any significant AR’s associated with it. These look to be mainly light to at times moderate snow producing storms for Mammoth. Some storms will be very cold! (Lots of cold powder)
6. More Later…..

Preliminary snowy dates “subject to change“;  Feb 3rd; 5th and 9th.

Dr Howard and the Dweebs…………………….:-)

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After an El Nino like pattern in December and January, the Northern Hemispheric Pattern has once again shifted back to La Nina. After a shot of cold water emerged over the Central Pacific due to enhanced trades, this has had the affect of returning our pattern to one of colder than normal with drier than normal conditions for California.

According to the Climatic Prediction Center, A transition from La Niña to ENSO-neutral is anticipated during the February-April 2023 season. By the Northern Hemisphere Spring (March-May 2023), the chance for ENSO-neutral is 82%.

So might this resurgence of La Nina and its associated pattern be the last?   Will See!

Weekend storm:

For the past 24 to 36 hours, the global models have been back peddling on the precipitation forecast for Mammoth Lakes and Mammoth Mt.  Here is the latest 12z/4:00AM updates.

The main differences between the GFS and European models is this;

The Euro is just slightly slower and colder than the GFS and has a little more snowfall for our area.  And….The upper low has no over water trajectory now, and the upper jet is off shore, and more NW oriented.

Both models agree that this system is much drier now with snowfall amounts for Mono County in the 1 to 6 inches range by Late Sunday night. 700MB temps go down to -16C Monday AM. That’s 3 degrees F at 10,000 feet Monday AM in Mammoth, free air conditions.

With Inversions setting in quickly Monday into Tuesday, Bridgeport Valley may go -25F Tuesday AM. Freezing Fogs to return next week for Lee Vining as well.

Longer Range:

We will continue with a hemispheric pattern associated with La Nina. Weather systems seem to be pretty tame through mid month. There is a small system on the 3rd and another small system on the 9th. Both are in the 1 inch to as much as 6 inches category.

Dr Howard and the Dweebs………..:-)