Powerful Jet Stream…….Rain & Snow

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Good morning Weather2020 bloggers,

A strong storm system is blasting into the west coast this morning.  The Lake Tahoe area is a target this morning with 125 mph wind gusts forecast to occur today over the higher ridges.  Can you imagine that? Take a look at this forecast alert:

Lake Tahoe Area Forecast:

 

  • Timing:  Snow and rain will spread quickly across the Sierra and Lake Tahoe basin this morning and become heavy. Snow will decrease briefly this afternoon…with bands of snow and snow showers developing again tonight through early Friday morning
  • Total snow accumulations through Friday morning: Above 7,000 feet….1 to 2 feet with locally up to 3 feet near the Sierra crest. Below 7000 feet…7 to 14 inches with 18 inches possible west of Highway 89
  • Winds: Southwest 30 to 45 mph with gusts up to 65 mph. Ridge gusts up to 125 mph. The strongest winds are expected through 8 AM this morning. Damage to trees is possible
  • Snow levels will start out high near 8,500 feet early this morning, then falling quickly to below 5,500 feet by midday. Lake level is 6,200 feet

The weather pattern is about to buckle. What I mean is it is about to go from zonal flow, west to east, to more wavy and meridional flow, north and south.  A powerful jet stream is now heading towards the west coast. Take a look:

Powerful Jet Coming In

As this jet stream blasts in the morning, the Lake Tahoe area and the higher ridges are in the right position to have these high winds reach the surface. Look at what happens to the flow aloft by noon Friday:

1

This storm will move into the southwestern part of the nation by Friday.

2This next map shows what the weather pattern is forecast to look like by Sunday morning, December 13th. This storm is moving through one of the LRC long term long-wave trough positions. It is actually taking a great track to bring Kansas City snow, but guess what….it’s likely going to be too warm.  We forecasted this storm, and this developing series of storm systems to arrive during the next ten days to two weeks. Take a look at the last cycle, or 50 days ago:

LRC Cycle 1 October 23

The weather pattern sets up every fall between around October 1st and November 10th, cycles, and then repeats. We have identified the likely cycle length and if you go back 50 days you can see a similar storm system on October 23rd. The December version is a bit stronger and farther south, but even the shape of the storm is the same.  Look at the dip in the flow over Nebraska and the Dakota’s. A similar dip is approaching the plains states this weekend.

I don’t know how to say this any other way, “the lightbulb” went off!  In the past seven to ten days the LRC finally came into focus. It is really one of the more incredible moments every year and it’s hard to describe. And, those of you who have been following the LRC with us for the past decade will likely understand the best. This is the first example of the year. You can not make these comparisons before, roughly the end of November. The old pattern fell apart in September and early October and we now have a pattern cycling that has never happened before.  This is just one snap shot in time. It isn’t just this one day, but the entire pattern that is cycling.

This storm is likely taking a great track for heavy precipitation in the KC metro area and surrounding areas. It is also taking a track that would usually produce heavy snow, but it appears it will be just a bit too warm. We will continue to monitor this closely.

Here is a rainfall forecast from the 06z (midnight) run of the GFS model:

Screen Shot 2015-12-10 at 7.25.31 AM

Let’s see how the models look today. The models will narrow in on a more consistent solution after this energy blasts over the west coast today.  Most of the energy has been located over data sparse regions across the eastern Pacific Ocean.

Take a look at what is happening and forecast to happen with the Arctic Oscillation:

AO December10

The AO has been staying, “living”, mostly in positive territory this season. It did dip into negative territory one time around the second week of October, and it is forecast to do about the same type of dip in the next week. Let’s continue to monitor this closely. When the AO and NAO dip into negative territory there is an increased chance of blocking and the potential for the Arctic air to build and blast south. So, we must pay close attention to these developments. Some of the models have it getting pretty cold in ten days or so.

Have a great day and thank you for participating in the LRC Forecast Experience Blog. Let us know if you have any questions or comments.

Gary

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rickmckc
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rickmckc

What a gorgeous December day. Played golf this afternoon and it felt like mid-October. I love El-Nino!

Mr. Pete
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Mr. Pete

I really do think that all of this snow will verify in one whopper in February.

Dale
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Dale

00z NAM shows no snow for our area.

Alice
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Alice

https://www.ncdc.noaa.gov/news/historical-probability-of-white-christmas

It’s better living here, where there is at least a small chance of a white Christmas, than living someplace where there is no chance. Been there, done that. Living in Hawaii for 3 yrs, then Guam was nice, but I missed the 4 seasons ! Any chance is better than no chance

Bill in Lawrence
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Bill in Lawrence

Gary: Good evening to you sir!!!! Thanks so much for the kind response above….I have always so enjoyed this blog…always enjoyed how you take time to teach and explain things…it is awesome!!!! 🙂 Well…that didn’t take long did it…flipped in two runs!! As I said this morning….with the GFS running four times a day I would not be surprised to see 6-7 runs between now and Sunday with us in the 50’s for mid to late next week. I would not expect a consistent performance until at least Sunday…maybe 12Z Sunday but probably 0z Sunday. I am still sticking with… Read more »

Rockdoc
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Rockdoc

Uncle Bill, hope you don’t mind me calling you that. Any links for monitoring the AO and NAO? Sources please. Hope all is going well there in Lawrence.

Bill in Lawrence
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Bill in Lawrence

Rockdoc: Google CPC AO and that should take you to the pag and Gary has posted it in the blog entry. You can also access the NAO and PNA from that site. I have always thought that the PNA is another good indicator. These sites will also give you acess to data of each index going all the way back to the 1950’s. It is interesting to look at the archived data. I keep thinking of 1989 and how positive the AO was for most of November which translated into an incredibly warm month and even into first wek or… Read more »

Rockdoc
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Rockdoc

Thanks?

Rockdoc
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Rockdoc

Good Evening Gary. As you had indicated earlier, the storm system is just now approaching the west coast. The way I see these systems, and I believe you had mentioned this, is that until they are over land and weather measurements can be taken and fed into the models, the models have a hard time projecting forward. Especially with the “buckling” of the jet stream, and development and shifting of the surface lows can be a pain in the rear. This being said, I’m impressed that these models can take into account all of the data parameters and model in… Read more »

stl78
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stl78

That was the first time I looked at the nam…..interesting

Dale
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Dale

I sense backpedaling from Gary. He seemed very sensitive about the anchor claiming he said it would snow before Christmas. He said we were in a warm pattern…oops! That almost guaranteed snow seems to be going away with each model run.

Alice
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Alice

That is why I picked Feb 6 for our first inch. With the “don’t jump to conclusions” warm pattern that we have been in since the new LRC started forming.
And we have been in the warm pattern most of the time since.
I thought about Dec and Jan typically not being snowy months, but we have had some big snows in February.
I know I am probably wrong, and the first inch will probably happen long before Feb 6, but I think most of the (KSHB forecast of 23 inches ) will happen after the middle of January.

stl78
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stl78

Crickets after the 18z, hmmmm. Relax terry, it’s just one run.

terry mercer
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terry mercer

Yeah but it the same way they take one run and run with that. I’m right about that?

terry mercer
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terry mercer

Wrong Dale and that was not four days again. This is the second day.

f00dl3
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f00dl3

Hate to say this but I think it’s safe to say that Gary’s first inch of snow date (16th) and his 90% chance of us getting our first inch of snow by Christmas are both wrong. I think right now it’s more likely we will have a tornado before Christmas than snow.

Rockdoc
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Rockdoc

You do mean a “tornado blizzard” don’t you, or is that “blizzard tornado”❄?❄

terry mercer
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terry mercer

From Gary dated December 8th blog A big change in the next 5 days. So the models are going to go back and forth until at least Sunday so the models will not be consistent on what they are predicting as of right now.

Dale
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Dale

Lol that’s four days ago. A ton of things change in four days.

Alice
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Alice

Dale,
That was 2 days ago, not 4.

Mr. Pete
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Mr. Pete

No arctic air for the middle of next week from what I see.

Heat Miser
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Heat Miser

Yeah, I think going out a week is as risky as we can even realistically contemplate with the model runs…going out to two weeks is pretty much just taro cards and crystal balls

Morgan
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Morgan

Models two weeks ago were showing this warmth. So yes, we can put some stock into long range model projections, given the persistently warm pattern we’re in. Transient cold shots that last three or four days is what we’ll have to live with this year. Let’s hope it’s stormy when that happens.

heat miser
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heat miser

Just because it showed warmth two week prior doesn’t mean there is a correlation to accuracy…it’s just as often wrong about that

terry mercer
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terry mercer

Gary are any of the models showing when the Arctic cold or cold air coming in middle of next week?

Morgan
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Morgan

So much for that cold signal around Christmas. Not a good look on the 12z GFS. More GLC rain storms. Sucks to waste all of this moisture on rain this time of year.

CRW
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CRW

Like someone said a while back, the cold is always 10-14 days away.

HEAT MISER
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HEAT MISER

It sure is a good thing that the GFS is meaningless two week out huh? Nobody would much stock in that…oh wait…..

Dale
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Dale

Kinda like you do when it’s showing a snowstorm? Thanks CRW.

Heat Miser
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Heat Miser

Naw…I recognize it’s totally unreliable…just hope it happens

CRW
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CRW

We will probably know for sure a day or two before the snow actually happens.

stl78
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stl78

It’s not just warm in kc. I’m in Minneapolis right now where it is in the 40s and raining. Hard to believe its raining in dec in minn!

MMike
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MMike

Gary H,

All rain this winter….at least we’re getting moisture. It was 58 degrees this morning when I woke up………………….WHAT?????

I wonder if we can some how figure out how to get it to snow at 60 degrees.

I was reviewing the last few runs of the GFS and GEM models…the weirdest thing happen when I I would play each run…a screen popped up and it said….”No snow for KC…sell your shovels….way too warm this winter” Must be a new feature they have…messaging.

terry mercer
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terry mercer

Yeah right very funny. You Must have already had too much eggnog before Christmas lol.

Dale
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Dale

At least we are getting some storms in KC. I am glad to see exciting weather, even though it’s not snow. Let it rain, let it rain, let it rain!

Hunter
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Hunter

Are any of the storms that fit the LRC for this cycle expected to be complex, Gary? I know last year that word was thrown around a lot as we were just not in the right spot.

Why is it always complex when the air is cold enough to produce snow (which I have noticed storms are notorious for missing us when it’s freezing or below)? But when it’s warm for just rain, the storm track is just so perfect we get a good bout of it…

Gary H
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Gary H

Last couple of runs of the GFS has some very interesting winter weather near or over KC on Christmas Eve day. Looks like something to definitely watch. Canadian (GEM) is a bit different bringing the storm in a few days earlier (but still snowy). Euro (00Z) is nowhere close to either, but let’s see what 12Z says. Any ideas whether the recent GFS solutions fall in line with the LRC?

Alice
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Alice

Here are some interesting stats put out by the NWS Kansas City…
Late first snow events followed by the total inches those same winters…

First snow Total for the year
Jan 21, 1980……..23.5 inches
Jan 18, 1955……..20.2
Jan 7, 1934……….7.2
Jan 2, 2002……….8.6
Jan 2, 1897……….28.9

(Were any of these years El Nino years ? )

MMike
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MMike

Got all the sandbags ready for the flooding rains this weekend….what a waste of a great storm.

IT should SNOW this time of year!!!!

Gary H
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Gary H

I completely agree. So frustrating! But I’m enjoying the nice weather too. Very odd to still be doing yard work this time of year.

Rockdoc
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Rockdoc

06z run of GFS showing what could be a white Christmas? If the surface low shifts just a wee bit south then there could be even more snow. Most of the snow is to the north and into Iowa right now, but nonetheless temps are in the teens starting around the 24th to be supportive of snow⛄ Something to keep our eyes on.

Craig
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Craig

If this is Dec 12, one can only imagine how interesting this might be 100 or 150 days from now. Be sure to scroll down to the part about Eastern KS and MO.

http://www.spc.noaa.gov/products/outlook/day3otlk.html

Getmbuck
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Getmbuck

Gary any idea at this point on the timing of the weekend precip? Mainly looking for approx start time, peak hours and projected end time. You did a good job on predicting the timing for the thanksgiving deluge so wanted to see if you are at that point yet for this one

LS Mike
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LS Mike

Bill, you mentioned Possum Kingdom Lake, Texas. I’ve been going their my whole life, and have a cabin their. Small world!

Bill in Lawrence
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Bill in Lawrence

LS Mike:

Small world indeed!!! 🙂

My fiancee’s family has had a place there for years as well. Beautiful area for sure!!!

We were just down in October-nice to finally see the lake filled back up!!!

Anonymous
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Anonymous

Bill, my place is around the bend from Hell’s Gate have to go by boat to get to it. I told my peeps down there D/FW area to not worry the lake(S) will stay full all year. Of course they said I doubt it and mentioned back into a drought, this was right after October first of November. I told them that the pattern has changed and your in a good spot for lots of rain. Of course I was using the LRC and look what happened on Thanksgiving…. They got a ton of rain again.

LS Mike
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LS Mike

Bill, my place is by boat access only around the corner from Hell’s Gate, beautiful lake. So thankful it has filled back up. Told my family that it will stay full this year with the new pattern, lots of rain down there.

Anonymous
Guest
Anonymous

Bill, you mentioned Possum Kingdom Lake, Texas. I have been going to that lake my whole life and have a cabin their. Small world !!!

Rickmckc
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Rickmckc

It really is astounding to see a system so perfectly located for a major snow storm in Kansas City produce rain in mid December.

Bill in Lawrence
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Bill in Lawrence

Gary: Good Morning to you sir!!! A couple of random observations/thoughts….I’m sure the limb will break!!  It appears ( I think??) that the 0Z GFS Operational model finally caught on to the possibility of the AO going negative around the 16th of December. There is some weak blocking beginning to show up in the Eastern Pacific around that time and the surface temps/solutions began to show that on this run. We look to stay below for freezing for around 3-5 days beginning next Thursday before we would warm to just above for about 12 hours until what I believe… Read more »