Archive for January, 2023

Surface Low crossed the Sierra this morning and is located about Hawthorne, Nevada. Nice deformation zone set up between Hawthorne, NV and up into Reno providing snowfall over Western NV and the Eastern Slopes of the Sierra. SW flow has increased in Mammoth with whiteout conditions at this time. Please do not drive under these conditions… Please check with Caltrans before traveling north or south on Highway 395. Mammoth Mt shows over 4 feet storm total over the past few days….Up to another foot is possible today…. Platinum Powder Alert for Tuesday from todays storm with one foot or better on the slope at 15:1 (Platinum Powder)…

Weather Discussion:

Latest Model Simulations show Snowfall rapidly tapering off after mid afternoon and will end by early evening.    After the break in the snowfall later today, It will be quite cold Tuesday with diminishing clouds then clearing over night Tuesday night. Low temps will will go -17F to -6F throughout Mono County early Wednesday morning and although the Blue Birds are gone, it will be that kind of day!. Cold Dry Powder a sure bet with EGO snow! Make sure you have the right wax for the very cold snow in the morning…

Another weaker system will bring some 1 to 5 inches Wednesday night into Thursday AM with high snow to water ratios. That will be the last storm in this cycle. Temps will remain cold for the rest of the week with some moderation over the weekend. 20s for highs.

Looking at next weeks weather….Over all great!  There is a cold system that drops out of BC, Canada bringing very cold air and NE wind over the Sierra Crest Monday the 23rd. Its to soon to see if we get any meaningful upslopes from it but it is not expected to bring any substantial snow…..Mainly snow showers Monday. Today’s model simulations show the wind with this pattern at 700MB (10,000 feet) is strongest over the Northern Sierra. The system spends time over Tonopah, NV, during early morning hours Monday…..Best chance for upslope.

Thereafter, there will be some windy periods week two but northing unusual and it looks like precipitation will be below normal.

Tropical Forcing:

There are a few very interesting developments the last week of this month.

The first strong MJO; Madden Julian Oscillation is expected to affect the mid latitude flow toward the end of the month. Retrogression is being shown in the global models the last week of the month of January. Another storm cycle is now a good possibility as the MJO is forecasted to be very strong in the RMM Phase 3. Composites show wet weather for CA in January and February for that phase.

Although a new long wave Trough is expected to carve out over the far Eastern Pacific toward months end, we do not know if this pattern will set up with AR’s again.  However, today extended model 12z GFS simulations for early February shows that; so there is some possibility although that pretty far out in time. Therefore please consider your snowpack around your home and or businesses and diminish the loading on your roofs. Do this before the end of the month!! The last series of ARs were not really warm AR’s. They were not the Colloquial Pineapple Connection as the moisture was mainly subtropical. Should an intense static AR develop from Hawaii, with freezing levels well above 10,000 feet, that could be disastrously.  While there is no forecast for that that at this time, it is still a good idea to have roofs shoveled in the meantime.

See one possibility below:

I also wanted to add that there is a very strong Strato-Warming event taking place over the Arctic in a few weeks. See graphic Below.   That will most likely have an affect on our Northern Hemispheric Pattern. However, it is unknown to what change it will bring.

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Dr Howard and the Dweebs…………………:-)

1-15-2023 830am

Exciting meteorological development with this last significant storm.  The new ICON model 12z run shows the upper level wave with this last system, coming through Sacramento late morning while a surface low is over Monterey Bay at 400am and crosses the Sierra near Mammoth late AM. This will bring a bonus of snowfall to Mammoth Monday with some 3 more feet expected on the mountain. The Snow will be light powder with higher snow to water ratios than past systems this month. 12 or 13:1

I am still expecting another a smaller storm Wednesday night into Thursday with light to moderate amounts. The Euro is in some what agreement. See below…

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Saturday night 9:55pm….1-14-2023

Outlook

Just saw the new 00Z Sunday GFS model run.

Apparently,  this model run wants to dive the following short wave after Tuesday, further west to the Northern CA coast late Wednesday afternoon before progressing it through Central CA Thursday. Previous runs had this as an inside slider with mainly wind and very light snowfall. Well need to see the Euro come into agreement tomorrow and if it does, this new twist brings the possibility of moderate snowfall Wednesday night into Thursday. Preliminary estimates indicates between another 5 to 10 inches of snow if the Euro comes into agreement. Stay tuned….

After a decent break, Friday, Saturday 20th and 21st. into that early Sunday. The next system system drops south from Alberta and British Columbia, Canada. So it’s source region is dry and cold. It heads for Southern Nv and through the process,  can give us cold, windy, showery weather. This for Sunday night and Monday the 22nd and 23rd. Thereafter, as indicated in previous discussion, serious retrogression of the Eastern Pacific high begins to occur.

Sometime during the last week of January, we’re likely to see a major storm for California. I don’t see an AR yet but a strong subtropical tap could occur as the Trof that going to develop shows up as positive tilt and is deep as well.

Comment; while the storminess the past two weeks was not related the MJO forcing, the next storm cycle apparently is.

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As of 9:00AM, Mammoth Mt has picked up about 9 to 12 inches of new snowfall since yesterday when the storm began. Another 4 to 5 feet is expected by Tuesday AM. Winter Storm Warnings are hoisted now through Tuesday at 10AM. Since the mountain has received about a foot, up to another 5 feet is expected by Tuesday AM.

Fridays System has passed bringing mainly light to moderate amounts. This current system has the AR attached to it so heavy amounts expected to develop later this morning into the evening. After somewhat of a break Sunday with very light snowfall, the last of this storm cycle will move in Sunday night with strong winds and heavy snowfall though Monday PM. Expect possible white out conditions in the morning.

The Monday/Tuesday system will be the last of the storm cycle. The pattern transits to an inside Slider Type/Great Basin low…Wednesday afternoon into Thursday. This pattern may offer some snow showers with gusty winds over the upper elevations and somewhat colder temps. Highs in Mammoth will be in the mid 20 mid-week. Then improving weather Friday into Saturday before another system Sunday afternoon into Monday dives north south into the Great Basin and desert southwest.  This is a windy pattern over the Sierra Crest and north wind prone areas. Some light snowfall is possible with light amounts if any.

The extended out for the following week shows another cold Great Basin Slider the 25th and 26th bringing the possibility of more upper elevation wind and light snow. The upper air hemispheric pattern is suggesting this morning that retrogression will begin to take place around the 26th. The MJO is strong going into Phase III of the RMM. (See previous post for that comment)   So odds are good that the eastern pacific high backs up again and a new storm cycle will begin just before the end of January.

Highs mid week in the mid 20s lows in the single digits and teens.

Dr Howard and the Dweebs…………….:-)