December 2021 Weather Discussion

[tron777]

12Z UKIE for Wed showing 0.02-0.05" of QPF across the heart of the Metro area for the light snow "event."

[tpweather]

12Z GEFS looking wet and not white for next Sat. 12Z CMC has the multi low idea but it's all rain . A much slower solution as well, just no cold air to work with at all.

I agree Les the CMC looks similar to the gfs all week. Next weekend we will see rain Saturday but there should be some cold air coming with that system and that is where I see the front stopping and another system forming. That is why I have talked about late Saturday into Sunday as a chance for snow to be near us and even more likely in the northeast. I believe the models are raising heights too much in the central part of the USA late next week due to some storminess moving its way into the pacific coast. That is how I see it playing out at the moment and need the Euro to help me out but if that model can keep its hot streak going. These systems are picking up some decent cold air with each front and that is why I have been going with the several systems this week until the weekend. Dense cold air will win out in early Dec-early Feb most of the time and models will usually correct itself towards these events.

[tron777]

12Z GEFS looking wet and not white for next Sat. 12Z CMC has the multi low idea but it's all rain . A much slower solution as well, just no cold air to work with at all.

I agree Les the CMC looks similar to the gfs all week. Next weekend we will see rain Saturday but there should be some cold air coming with that system and that is where I see the front stopping and another system forming. That is why I have talked about late Saturday into Sunday as a chance for snow to be near us and even more likely in the northeast. I believe the models are raising heights too much in the central part of the USA late next week due to some storminess moving its way into the pacific coast. That is how I see it playing out at the moment and need the Euro to help me out but if that model can keep its hot streak going. These systems are picking up some decent cold air with each front and that is why I have been going with the several systems this week until the weekend. Dense cold air will win out in early Dec-early Feb most of the time and models will usually correct itself towards these events.

One thing is looking more certain, after we get past next weekend's system, Dec 13th thru at least the 20th looks like a major torch. Could see quite a few 60s throw in there with 70 degrees as nearby as Louisville. GFS, GEFS and EPS all look very mild during this period.

[Bgoney]

I'm going to hold off thoughts for week 3 until we finish week one. No changes however through the 15th . Warmth / cold interspersed as usual. Tuesday we may see teens nearby for lows but we warm to near normals and slightly above through the week until the front passes next weekend and repeat. No arctic air for the OV through the 15th.
Here are lows for the next 10 days (EU)

floop-ecmwf_full-2021120500.sfct.conus.gif

[MVWxObserver]

Glad that the afternoon is dry for the Bengals / Chargers game. Should top out at around 60 degrees a bit later for down that way.

Currently 45 here in G'ville.

So far by the way Cincy is performing in the 1st half, you'd think they weren't in a wild card contending spot!

[tron777]

12Z Euro basically has next to nothing now on Wed... shears the energy out too much. Then it continues with the two low idea for next weekend. Rain Sat changing to a wintry mix by early Sunday morning before ending.

[tron777]

18Z NAM tries to blow it up on top of us for Wed's light snow event. 0.05" QPF for CVG.

[Bgoney]

The promising MJO forecast looks nice , but given recent model failures in their progression of its eastward motion in that they are almost always to aggressive. Its another we'll see deal.. Probably some kind of bias. Hopefully they are more in tune with the upcoming weeks

Models have been too strong with the amplitude as well as the phase. As of 12/3, the Aussies have it in Phase 6 and fairly strong compared to what we've been seeing. So this go around attm anyway it is stronger then what we've been seeing and it is on the move at this time. Question is... will it stay that way and continue to move into the West Pac, or will it crap out as it's done in the past? The last time this was expected to occur, tropical cyclones developed in the West Pac and killed the MJO wave's energy.

rmm.phase.Last40days.gif


Current look at the West Pac:


abpwsair.jpg

I only use the Aussie's on the mjo. Over the years far and away the best in regards to their modelling of the mjo.

Visiting the MJO again and why I'm skeptical of the models progression time-line, using the 850 anomalies, yes we have an uptick in westerlies and some movement but notice we also have a easterly burst in the central PAC , pushing back if you will and possibly impeding progression at.least temporarily

u.anom.30.5S-5N (1).gif

[tron777]

61 degrees here with light rain beginning.

[MVWxObserver]

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[tron777]

18Z GFS has 0.09" of QPF on Wed for CVG. All rain for the next weekend storm.

[Bgoney]

That Alaska storm observations . 949mb low alongside 1047mb high, yea that'll do it

Severe storm overnight over western Alaska. Wind sensors have failed at many FAA automated stations, but winds that have been recorded thru 6am AKST Sunday include 99mph at Tin City, 75mph at Savoonga, 67mph Hooper Bay, 59mph Shishmaref and 57mph at Nome.

FF3Ga2oVkAIZJSI.png

[tron777]

0.18" so far here for our current system. CVG checking in with 0.22"

[young pup]

That Alaska storm observations . 949mb low alongside 1047mb high, yea that'll do it

Severe storm overnight over western Alaska. Wind sensors have failed at many FAA automated stations, but winds that have been recorded thru 6am AKST Sunday include 99mph at Tin City, 75mph at Savoonga, 67mph Hooper Bay, 59mph Shishmaref and 57mph at Nome.


FF3Ga2oVkAIZJSI.png

99 wow. That would be wild to see and feel.

[MVWxObserver]

* Primary threats include...

A couple tornadoes possible

Scattered damaging wind gusts to 70 mph possible

Isolated large hail events to 1 inch in diameter possible

[MVWxObserver]

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[cloudy72]

So high temp today just after midnight of 60. Storm total rain 1.23”. Had quite the lightning show as well earlier. Not a bad night for December!

[tron777]

Lot of heavy rain and even a few severe t-storm warnings overnight as well! 61 for the high before we started to drop. 0.90" at CVG as of 6am. Will post my total shortly. Look for winds to stay strong today out of the W and NW with falling temps into the 30s later this afternoon.

[tron777]

Checked my gauge and got around 0.86" here.

[Bgoney]

Since 1980 first 5 days December mean

Screenshot_20211206-063520_Chrome.jpg

[tron777]

Thee are a few dud's in there but a couple of them went on to have great winters. 93-94 and 13-14 are prime examples of good pattern flips. But at the same time, there is an equal chance that we never flip and the entire winter is a dud. Hopefully we'll get the flip this go around. We have been on a bad run of Decembers though. 2010 was the last good one we had.

[tron777]

For the light snow maker Tues night into Wed morning... models still vary on the placement of the light snow band as well as how much we get. From nothing to an inch or so is possible in the data. So we'll just go with the festive look as we've been saying on here with a covering not out of the question. Then we warm up again with a touch of rain Thurs then a more potent system again for Fri night into Sat followed by another temp drop. We could spike up into the 60s again ahead of that system. Do we see one low for rain / t-storms then the drop or do we see the multi low idea which means one low drags the front thru, then it stalls with a second low riding up along it to produce a bit of snow? That's the task ahead of us for this weekend.

[tron777]

Quick post on the long range... I'm going with a boring and mild pattern if not a torch for Dec 13-20th. Then as we approach Christmas, does the pattern change come in time for Christmas - New Year's period or do we continue to roast? We will continue to talk about those prospects as we get closer but there is no doubt in my mind... we've got a solid week of very warm weather coming up.

[tpweather]

Good Morning and the calmness much of the country had in November compared to normal has ended with a bang. Another big storm this weekend as well. As for the week the rain will end this morning but the winds should be rather strong until early evening. Snow chances and yes we have at least some chances over the next 7 days. First will be overnight Tuesday through early Wednesday morning. Should be enough moisture to least see snow flying and some folks could get a nice coating especially on grassy surfaces. Thursday morning as warm air returns quickly we need to see if that produces some light snow before switching to rain. Last chance would be late Saturday through Sunday morning. Again these warm ups before a front comes through looking more impressive than I expected which tells me these storms are stronger. How quickly does the cold get in here later Saturday is the key question. This is the old cold get in here before the precip leaves which usually is not the best situation for us to get a decent snow. That storm will most likely give the northeast a nice snowfall late in the weekend. Les has been talking about the warmth for the week of the 13th and he is correct and is this the old calm before the storm playing out which leads to a more winter type set up for the week before Christmas. One key is one that Bgoney is talking about and that is the mjo progession. How this plays out is no doubt a key in the long term pattern and something we will be watching closely. The current wave does have some resistance and if somehow it loses then expect a much milder period the week of Dec 20th. I have touting the wave winning and moving into phase 7 which is usually a good sign for colder air working in here from the northwest. Very busy December ahead and my guess the changes we see on the models will be head scratching by this time next week.

[tron777]

I think by and large we're on the same page here Tim. I think Bgoney is as well. The MJO getting into the more favorable phases is one key to the overall process for sure that we will be watching as well as Alaska. Does the very cold air stick around there, or can we get some ridging going to put the cold air on the move? Lots of things for us to watch globally in addition to our local weather.