Dry January Pattern to continue…..Possibly through months end…..Milder weather expected next weekend…

January 17th

 

Both GFS and Euro ensembles are showing much more promise this morning of a stronger pacific undercutting pattern developing around the end of the month.  A lot needs to be worked out in the meantime. However,  AR moisture may come into play, confluent with a decent eastern pacific Trof. The Dweebs just about gave up hope until seeing this mornings ensemble runs. Also the GFS phase space is back on line to help with confidence building when we near the last week of the month.

Dr Howard and the Dweebs…………👍

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Our January thaw will continue another 1 to 2 weeks now as high pressure aloft builds over the Pacific NW.   There is some hope that some undercutting of a weak branch of the westerlies may occur before months end. However, at this time, it is sketchy at best.  Tropical modes of variability are expected to remain weak with no real driving force seen at this time.  About the only ray of hope is surface cyclogenesis that may spin up, off the coast of Japan about the 24th that may propagate enough energy eastward for a weak system that would undercut the positive height anomaly by the 28th or 29th. The main upper height anomaly is expected to retrograde during the last week of the month.

In the meantime, expect on again, off again variable high clouds from a general upper level weakness in the mean,  off the Southern CA. Coast.   This has brought a lot of high clouds to our region the past several days and is expected to continue in this fashion through mid week.

 

Expect highs temperatures in Mammoth to range in the 40s with lows in the upper teens and twenties. It may be a bit milder next weekend as pressures aloft build even stronger. No important winds expected this upcoming week…..

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

A Flip in the Hemispheric Pattern to +PNA will give us our January Thaw toward Mid-Month….A great time to enjoy all that December snowfall!!!!

Jan. 11TH

 

Pursuant to the last post, it is evident that there will be no major off-shore event for SOCAL on Friday.  Nevertheless, there is one occurring now with warmer temps expected Wednesday.  The upper low SW of Southern CA gets picked up early next week for a few showers in the LA area weeks end. There is likely going to be another forming to replace it later next week.    It all adds up to a dry pattern with variable high and mid level clouds for the Sierra into next week. The outlook is dry for the next 10 days.

The big driver for big weather all revolves around the MJO I believe and where its going to go. If it circles back around to phase 7, were off to the races!!  I think it will be a lot more evident net week.  Still expected big changes, during the last week of the month of January.  As always stay tuned……………………….:-)

 

Dr Howard and the Dweebs………………………:-)

 

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January 5th-2022

 

Not much to add to the discussion below.  The last system in the series is actually left over from the previous pattern. That will be coming through this Friday.  Expect very light amounts of snowfall, (1 to 3) inches.

That system will leave a cooler airmass for the weekend,  with high temperatures returning to the 30s with overnight lows once again in the teens and twenties.  Moderate to strong winds will pick up over the ridges beginning this Thursday night into Friday.  The storm will exit Friday night and leave a beautiful weekend as an upper ridge, developing in this new pattern builds over the west coast. Expect temperature inversions to strengthen with the possibility of Pogonip Fogs (Freezing Fog) near high elevations large area lakes, mainly in the high elevation valleys developing over this weekend.

 

The next weather feature in our long range outlook occurs next week as another short wave from the westerlies splits and spins up as a closed low well off the Central CA coast early next week. The upper low eventually forms a mid latitude REX Pattern as high pressure builds into the Pacific NW to the north of it about Friday the 14th.

This pattern this time of the year is notorious for strong gusty easterly winds over the Sierra Crest, in this case for the 14th. It can also set up a strong off shore wind pattern for Southern California. (Santa Ana’s)

A mid latitude Rex Block “in this case”, develops with High Pressure aloft and at the surface pushing into Northern California NW, couples with low pressure centered well to the south of it. Both the Sierra and Southern Ca are sandwiched in between these two anomalies and the end result is strong winds; 1. Strong east winds over the sierra crest and strong NE winds blowing off shore from the High Deserts of Southern CA to the coast via the Local Mt Ranges. The timing of this at the moment is Friday the 14th, if this pattern verifies!  Incidentally, there are some deviations that can occur with this pattern that can give the eastern slopes of the sierra precipitation. If the upper low sets up north of Vegas, Upslope snowfall could happen for the Eastern Sierra. However, at this time, the outlook shows the former pattern which is more common.

All in All it looks like a great MLK weekend weather wise for Mammoth. If strong east winds do develop, the strongest winds would be confined mostly to the lip of the Sierra Crest. The gradient is expected to relax over the weekend.

Longer Range;

The GFS is hinting at the possibility of a Sudden Strato-Warming event around Mid Month.  Stay Tuned!

The Climate Forecast System (CFS) is currently showing a break down of the current pattern during the last week of January. It suggests a -WPO with positive height anomaly centered over the Western Aleutians. This suggests a more southern storm track for the west coast.  Again as mentioned many times in earlier posts, this is not a forecast, just an interesting curiosity.

SEE:

 

 

 

Bye for now…………………….

 

Dr Howard and the Dweebs………:-)

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How quickly mother nature can turn it off!  This week a transition occurs from Decembers Ridge-Trough pattern over the Central and Eastern Pacific, to Trough-Ridge. That along with the flipping of the typical La Nina, North American Circulation Patten to the positive phase puts an end to our active wet pattern for the next few weeks this month. Sure we can still get a few storms, but its doubtful anything major. Time to get out and to enjoy all that great snow from December!   This weeks weather shows the last storm that moved over the North Pacific Block getting ripped apart east west, as strong height rises occur from the south. Expect mainly winds the next few days with fair warmer weather Wednesday and Thursday. There appears to be another short wave dropping down from the Gulf of AK, but it is questionable on how much snowfall we may get at this time. It is sort of running into a train wreck by the time it gets here. Hopefully we get an inch or two to freshen it all up for the weekend of the 8th. Daytime highs will be in the 30s and 40s with lows in the teens and 20s…

As far as weeks 2 and 3, Looking at the MJO, there are mixed signals.  The CFS weakens it rapidly then progresses it along the inner circle through phases 8 1 and 2.  Both the NCEP and ECMWF weaken the signal over the next week or two. Not any help.  The composites would suggest that if the MJO remained strong in phase 7 and 8 during the end of January and throughout February, we would expect a return of an active pattern.

I think that most importantly, the MJO Re-Emerges back out over the Central Indian ocean after the 16th and toward the 23rd; see the latest OLR with lasted CFS forecasts. Another flip in the PNA back to negative, might be expected toward the end of January.

 


Cold Western Trof Shifts East This Weekend bringing a beautiful ski weekend……Another potent storm sets up over the eastern pacific next week…..

12/29/2021

The forecast remain the same through the weekend as the current western trough gets ready to exit.   One more system today whose short wave is splitting off shore will bring the lions share of precipitation to Southern CA today and tonight.   Here in the high country, some 6 to 10 inches is expected on Mammoth Mt with half of that in town.

 

Tomorrows progs has the large scale upper trough shifting east a bit. That sends all the short waves down through Nevada. With short wave energy over land, over snow cover all the way to the Canadian border, there is little in the way of air mass modification, meaning modified arctic air will highlight our temps Friday into the Holiday with snow showers Friday. Bridgeport valley may go -20 to -25F Saturday AM. Good news is that if you Bridgeport folks want to warm up, drive up to the resort levels over the weekend as temps will be inverted! Highs in the 30s in Mammoth and June.

The trend in the longer term, IE next week is to keep the Tuesday storm, further north now. So not a lot of confidence on how much if any snowfall we may get. In the past 5 days,  the ECMWF had the right idea with west coast height rises VS the GFS that was overly deep with the January 4th storm.  It is now questionable if we will have a major storm here in the Southern and Central Sierra Tuesday as the models are trending that system more to the north, as the hemispheric pattern goes into transition.  The transition appears to involve a break down in the north-central pacific block. Additionally the Pacific North American pattern that has been negative goes neutral. This all adds up to a milder weather trend, especially later in the week with the possibility of west coast ridging returning.  Will an AR affect the west coast later next week before we ridge up?  Only the shadow knows!   😉

 

Dr Howard and the Dweebs……………………:-)

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One Item about weather patterns is that they never remain for long periods in their same form. Watching the week two (fantasy charts) is one way to catch what change there will be in our outlook period. This winter so far and Fall has been very humbling for the vast majority of climate or interseasonal forecasters as this is a La Nina Winter, and as winters go, they have a dry bias in the southern half of the state. As we have seen thus far, not all La Nina winters are dry for the south west coast.

Currently, according to the CA data exchange, the San Joaquin Drainage is 170% of normal for the 27th of December.   We are off to an amazing start!!

From the Dweebs Desk this Morning;

Our current frigid Western Trough has a couple more impulses to deliver. One that is bringing some wind to the high country this morning with a chance of light snow. Another that will bring light to moderate snowfall Wednesday and Wednesday evening. Some 5 to 10 inches is expected for Mammoth Mt by early Thursday AM. Daytime highs will continue in the low 20s with lows in the single digits. The cold upper trof exits Thursday, as a couple of inside sliders drop down the eastern slopes. Some light snowfall accumulations are expected Thursday evening and Friday. Beyond Friday is the skiers dream. A massive snowpack for December and fair weather. If you are reading this out of the area, this is the weekend you have been waiting for!!

Longer Range:

There appears to be one more storm associated with this pattern before the current upper high blocking pattern over the North Pacific breaks down. This new large scale trough is being handled differently by the global models in that the GFS is much deeper and has a stronger upper Jet for Central CA at this time.  It boasts some 3 to 4 feet of snow on Mammoth Mt at distance, However, the EC brings in about 1/2 of that.  The Jury will be in by this weekend.  The Big News is that the pattern is going into transition.  This begins about the 6th of January. The Classic Closed anticyclone shows up over Alaska. Additionally the European Global has the same Anti Cyclone Signature in the same time frame….So confidence is increasing in the outlook period. Why is this significant?  In January, when the upper jet runs Supreme, the westerlies can break under a blocking pattern when the MJO goes from phase 7 to phase space 8.  SEE Example above. The MJO progressing from 7 to 8 has the effect of extending the East Asian jet,  thus pinching off upper high and cutting it off over Alaska. This can unleash a nasty, mild in temperature and possibly strong to extreme AR along the west coast. Keep in mind that this is not a forecast at this time, but it is definitely something to watch out for the following weekend of the 8th and beyond.