December Forecast Discussion

[franklin NCwx]

Euro looks good. No bitter arctic air but air from Canadian origin is good enough.

It seems to be that over the past 5 days or so the 12z has been colder than the 0z.

[jburns]

No, it's a Southern thing and strangely it does happen sometimes. One example I can think of is back on January 6, 2008 we had severe weather here and 10 days later we saw half an inch of snow and three from that we got about an inch.

Add in fogs, possums, wooly worms, squirrels and moles. It's clear the level of scientific forecasting in the South has reached an all time high level.

[NCSNOW]

Euro gets late week inland runner to stall out in NE/Canada and it just keeps the Canadian origin air coming down as oppossed to this zonal flow pacific crap we've been dealing with. This is a good setup espeacilly in NC. If the late week lake cutter can get reved up, it will suppress the shortwaves that follow it the following week(Christmas) to move futher south increasing our chances. Otherwise without the cutoff from the late week inland runner, the preceeding shortwaves will just ride up to our west and it will be the same ol same ol. We clearly know what to watch for this week an root for in order to have a shot as some fun Christmas week. The Euro keeps most of NC below normal from next Saturday onward temp wise.

[HKY_WX]

The day 10 storm has real potential. The 50/50 low is brought back on this run of the EURO. If that is there, we will get an overrunning situation where we could see some ice or snow.

[HKY_WX]

JFYI, the euro has the 30 degree line sitting on the VA/NC border at hour 240 with a large batch of precip coming over. Verbatim looks like a zr/ip situation, however, the evolution it has with the pacific wave is very odd after day 8, so I think this will change quite a bit. But this is an icestorm on the EURO.

[beanskip]

Not sure how you can divorce the meteorology from the trends in model data -- all the factors you cite(-AO; SOI, MJO) are ultimately measured from computer analysis. Doesn't seem consistent to talk about an MJO forecast,b ut then want to discard other model forecast trends. I agree that both should be taken into consideration, but the reality is that the meteorological conditions depicted by the models have been prone to consistent error -- basing meterological forecasts without taking those errors/biases into account is a recipe for missed forecasts.

First, a little bit of apples and oranges here. This is sustained cold pattern vs. opportunity for wintry weather for parts of our region. The GFS having a cold bias at times in the long range is always expected. The Euro has thrown them into the mix as well. I'm not buying a major cold outbreak either in the near term, but the wintry wx could occur.

Regardless, there really isn't any forecasting going on at all here.. this is all based on statistical history of verbatim long range GFS numbers, and arguing this would spiral right back down to the ENSO debacle.

Let's try this approach... a sustained -AO, a recent tanking of the SOI, and an MJO consistently being forecast to trail into Phase 1 territory.. given our climatology, what would you forecast to occur over the next couple of weeks and into January? By the way, this isn't really a rebuff to your model statistic, just taking this on a meteorological point of view rather than statistical data of the GFS.

[MichaelJ]

With the models taking turns doing flips depending on the time of the run, it is apparent to me that the atmosphere is currently going through changes they are having trouble getting a handle on. Unfrotunately it appears to me the changes are a weakening (and moving further east) Greenland block and the sst's NW of the Nino3.4 area continuing to cool. Combining these two makes me think the the predominate flow for us in the SE will remain a zonal one for the most part. That is not to say that a powerful low going by to our north can not drag down some cold Canadian air, just that it would be very transient even if it does. The most likely form of wintry precipitation during these patterns are CAD events with zr as the predominate type. The NW mountains can still get some good snows from this pattern but the rest of us north of the NC/SC border need to be alert to zr events from time to time if the timing is just right (or wrong depending on how you feel about the dangers of zr) for some winter weather. While it is certainly not ironclad that the pattern would not change, the long lasting ability of the Pacific to stay in a -PNA this year does not give me much hope, especially considering the NAO looks to hang around Neutral at best for a while. Long way to go and many many things could change to a better situation for us so we need to just hope that it will and not live or die with the operational runs of the models. I am not ready to throw in the towel yet because there is so much we don't understand about all the indices and how they work but currently they are not in our favor.

[WilkesboroDude]

I believe the change is here. It's raining outside and into tomorrow. Another front Thursday followed by a much colder Friday. And by that time, we may find ourselves with a new thread for a new Winter Storm. JMO

[NCSNOW]

I believe the change is here. It's raining outside and into tomorrow. Another front Thursday followed by a much colder Friday. And by that time, we may find ourselves with a new thread for a new Winter Storm. JMO

You are correct. The pattern we have been in since Turkey day for our climate is in the infant stages of breaking down thankfully and should be completed by this time next Sunday. Doesn't mean we flipped 360 degrees like all of us would hope for, but we are through with the first half of December cooker that was taking place with much above normal temps and zero qpf (NC foothills/piedmont). Now question is what will it look like and how long will it last before changing again. Those questions can't be answered yet, but atleast we will start out next weekend with normal/below normal temps and maybe average precip chances thanks to a couple of fronts sweeping through. Being optimistic and realist it's better than the hand we got dealt the first 16 days of met winter.

[HKY_WX]

I agree that the track of the Pacific system doesn't dig as much as it should. Also, with the amount of blocking to the north I think this would track farther south. Still seeing a lot of varying solutions, but the one consistent theme remains an active Pacific in the 25-27 time frame with good high latitude blocking to the north. As others have said, the PNA ridge and position of the "50/50" low will be critical in determining the amount of high pressure that will feed into this storm. I do still think our wintry potential is on the table for now though.

Yea this is an extremely good look. If this is what actually transpires w/ the undercutting stj and 50/50 low, there's very high chance of a winter storm. The likelihood is that the STJ wave would shear out into pieces and the HP would slide into the great lakes I'm not understanding all the negativity around here lol.

[burgertime]

I agree that the track of the Pacific system doesn't dig as much as it should. Also, with the amount of blocking to the north I think this would track farther south. Still seeing a lot of varying solutions, but the one consistent theme remains an active Pacific in the 25-27 time frame with good high latitude blocking to the north. As others have said, the PNA ridge and position of the "50/50" low will be critical in determining the amount of high pressure that will feed into this storm. I do still think our wintry potential is on the table for now though.

Yea this is an extremely good look. If this is what actually transpires w/ the undercutting stj and 50/50 low, there's very high chance of a winter storm. The likelihood is that the STJ wave would shear out into pieces and the HP would slide into the great lakes I'm not understanding all the negativity around here lol.

That's why we have you guys here to walk us off the ledge. Here is to the Euro ENS hopefully it fully backs up what you two and others have been saying.

[Wow]

Not sure how you can divorce the meteorology from the trends in model data -- all the factors you cite(-AO; SOI, MJO) are ultimately measured from computer analysis. Doesn't seem consistent to talk about an MJO forecast,b ut then want to discard other model forecast trends. I agree that both should be taken into consideration, but the reality is that the meteorological conditions depicted by the models have been prone to consistent error -- basing meterological forecasts without taking those errors/biases into account is a recipe for missed forecasts.

The AO has been and is currently negative.. the SOI dropped swiftly last week, which thus supports the forecast MJO burst.

Models are always prone to error in the longer range.. no question there.

[HKY_WX]

Yeah I think too much is being made about model specifics 10 days out. The H5 pattern continues to strongly suggest a wintry threat is possible, and this is as good a look as we've had around here in a long time. I'll take our chances with this over what we saw last year!

No question.

[WidreMann]

The day 10 storm has real potential. The 50/50 low is brought back on this run of the EURO. If that is there, we will get an overrunning situation where we could see some ice or snow.

With the marginally cold air around, I'd say no.

[HKY_WX]

With the marginally cold air around, I'd say no.

Good, that's step one towards our first winter storm.

[tnweathernut]

You are correct. The pattern we have been in since Turkey day for our climate is in the infant stages of breaking down thankfully and should be completed by this time next Sunday. Doesn't mean we flipped 360 degrees like all of us would hope for, but we are through with the first half of December cooker that was taking place with much above normal temps and zero qpf (NC foothills/piedmont). Now question is what will it look like and how long will it last before changing again. Those questions can't be answered yet, but atleast we will start out next weekend with normal/below normal temps and maybe average precip chances thanks to a couple of fronts sweeping through. Being optimistic and realist it's better than the hand we got dealt the first 16 days of met winter.

Unfortunately, ALL we have done in the last winter plus is go in 360 circles, winding up in a warm and snowless scenerio time and time again. Sign me up for a 180 though, beginning next weekend. I will remain optimistic as I think things are changing. Even if the change is transient and we begin January warm, I can hold out hope for a rocking latter January, into February. Climate statistics say those are the preferred times for snow/ice in the southeast anyway.

[metalicwx366]

Add in fogs, possums, wooly worms, squirrels and moles. It's clear the level of scientific forecasting in the South has reached an all time high level.

Lol this is rich. Then you need -NAO -AO +PNA +QBO +PDO EPO 50-50 lows Neutral XYZ's Blocking Snowcover El nino MJO Active STJ H5 patterns SOI Bombogenesis and other stuff never heard of before.

[CAD_Wedge_NC]

The AO has been and is currently negative.. the SOI dropped swiftly last week, which thus supports the forecast MJO burst.

Models are always prone to error in the longer range.. no question there.

Yeah I think too much is being made about model specifics 10 days out. The H5 pattern continues to strongly suggest a wintry threat is possible, and this is as good a look as we've had around here in a long time. I'll take our chances with this over what we saw last year!

I don't undestand the problem is here..... This is exactly what most of us expected would happen. The models would tease us a bit with some pretty maps and we would undergo a step-down process until we got where we eventually wanted to be. I agree with Wow..... given the SOI data, the current state of the AO, the MJO, and the current SSW event, I would have to forecast cold incoming for the eastern US. If it doesn't happen, it will be going against some pretty reliable analog data.

[Brick Tamland]

So what happens if next Sunday the models are different and we don't have a winter threat around Christmas? Not saying that will happen and hope it doesn't. But the models have cried wolf so many times from 10 days out in the past.

[POWERSTROKE]

So what happens if next Sunday the models are different and we don't have a winter threat around Christmas? Not saying that will happen and hope it doesn't. But the models have cried wolf so many times from 10 days out in the past.

Life will continue to go on. It doesnt end just because winter doesnt occur

[Cold Rain]

Just wonder how long do we continue to let ourselves get burned by it. It seems a lot of folks are optimistic about this setup, and some still are pesimistic. I wonder if it is because they see something different in the setup or they just don't believe the models this far out.

So far this year, including now, there have been several good/awesome setups in the day 10 or 10+ time frame. And so far this year, they have not verified. That is the problem. Period. So far. If you take the map HKY showed and assume that it will verify, then yeah, we really could be in business. But so far, we have not seen that look have any staying power inside 10 days. This time might be different. We will see.

[dsaur]

Just wonder how long do we continue to let ourselves get burned by it. It seems a lot of folks are optimistic about this setup, and some still are pesimistic. I wonder if it is because they see something different in the setup or they just don't believe the models this far out.

No one with sense believes the models this far out. You look for trends. It wants to rain, it is slowing stepping down in temps. To get anything down that's frozen takes timing. Timing takes some "wait and see". The Gfs long range said I'd get some rain, and now it raining, but that's not near as hard as verifying snow out there in the way out. I'd believe rain over snow, because climo says so. But ColdRain made it snow two years ago on Christmas Day, and that had never happened down here. That's where the "wait and see" comes in, lol. If you get some around normal temps, with some normal rains, after Christmas you might see some ice, or something else, with timing, and a nice re enforced Cad. T

[metalicwx366]

Just wonder how long do we continue to let ourselves get burned by it. It seems a lot of folks are optimistic about this setup, and some still are pesimistic. I wonder if it is because they see something different in the setup or they just don't believe the models this far out.

Most just don't believe the models this far out. They keep showing great things at the same timeframe every run which is basically just pushing the timeframe back further and further. There was supposed to be a pattern change at the end of Nov, after Thanksgiving, after beginning of Dec, and that famous DEC 10th date.Now we are here in Mid Dec and its 80+ degs here today after a top 10 cold November. (6th coldest) . Only interesting weather will be Thursday if the severe weather happens.

[FallsLake]

RAH out of Raleigh has an interesting long range discussion this afternoon:

.LONG TERM /THURSDAY THROUGH SUNDAY/...

AS OF 300 PM SUNDAY...

A VERY ACTIVE PATTERN IS EXPECTED MID TO LATE WEEK INTO THE

WEEKEND... TURNING COLDER AS WELL. MODERATE CONFIDENCE.

MODELS FAVOR THE DEVELOPMENT OF A POWERFUL STORM THAT IS FORECAST TO

TRACK FROM THE MID-MISSISSIPPI VALLEY NE NEAR CHICAGO THEN ACROSS

THE GREAT LAKES THURSDAY INTO FRIDAY. THE TRAILING COLD FRONT IS

EXPECTED TO BE ACCOMPANIED BY A SHARP TEMPERATURE GRADIENT AS IT

SURGES EAST THROUGH OUR REGION LATE THURSDAY AND THURSDAY NIGHT. THE

FORECAST HEIGHT FALLS COMBINED WITH THE POTENTIAL FOR A SECONDARY

TRIPLE POINT LOW DEVELOPMENT THAT MAY TRACK ACROSS A PORTION OF OUR

REGION MEAN A BRIEF (6-9 HOURS) BUT SIGNIFICANT (HEAVY RAIN AND

POTENTIAL FOR STRONG TO ISOLATED SEVERE THUNDERSTORMS) WEATHER

EVENT. THE MOISTURE SOURCES APPEAR TO BE OPEN FOR BUSINESS WITH THE

SURFACE HIGH OVER THE WESTERN ATLANTIC EXPECTED TO TAP THE GULF OF

MEXICO AND WESTERN ATLANTIC AHEAD OF THE SHARP COLD FRONT. QPF OF

0.75 TO 1.25 MAY FALL FAIRLY QUICKLY WITH THE EXPECTED FRONTAL BAND.

FORECAST DEW POINTS MAY BE TOO LOW GIVEN THE CLIMATOLOGY OF THIS

EVENT... AND THEY MAY SURGE INTO THE LOWER 60S PRIOR TO THE BAND

THURSDAY. IF SO... THIS MAY CREATE A MORE SPRING-LIKE SEVERE WEATHER

THREAT GIVEN THE EXPECTED STRONG DYNAMICS AND WINDS WITH THE TROUGH

AS IT PUNCHES EAST ACROSS THE MOUNTAINS. THE POP WILL BE UPGRADED TO

LIKELY WITH A CHANCE OF THUNDERSTORMS. STRONG GUSTY WINDS WOULD BE

THE MAIN SEVERE WEATHER HAZARD.

THE POP WILL REDUCE QUICKLY BEHIND THE LINE OF CONVECTION WITH THE

FRONT THURSDAY NIGHT. IT WILL TURN WINDY AND SHARPLY COLDER BEHIND

THE FRONT LATE THURSDAY NIGHT AND FRIDAY. LOWS THURSDAY NIGHT SHOULD

FALL TO BETWEEN 30-38 NW TO SE. HIGHS FRIDAY WITH VARIABLY CLOUDY

SKIES AND A BRISK NW WIND WILL ONLY REACH THE MID 40S WEST AND MID

50S SE.

FRIDAY NIGHT THROUGH SATURDAY... A CONTINUED CHILLY PATTERN IS

EXPECTED WITH CONTINUED BRISK NW BREEZE FRIDAY NIGHT INTO SATURDAY

AS THE LARGE UPPER CYCLONE WILL BE SLOW TO DEPART NEW ENGLAND. LOWS

25-30 AND HIGHS SATURDAY EXPECTED IN THE 47-52 RANGE.

LATE WEEKEND... EXPECT A LARGE ARCTIC HIGH OVER CENTRAL CANADA TO

BEGIN TO EXPAND SOUTH AND EAST INTO THE MIDWEST AND GREAT LAKES. THE

FAVORED EC AND GEFS ENSEMBLE MEANS SUGGEST THAT THE COLDEST AIR WILL

REMAIN OVER THE MIDWEST. HOWEVER... ENSEMBLES SUGGEST THAT AT LEAST

A PORTION OF THIS ARCTIC HIGH MAY EXTEND INTO THE OHIO VALLEY AND

GREAT LAKES... THEN DOWN THE EASTERN SEABOARD INTO THE CAROLINAS BY

TUESDAY. THE NEXT POTENT UPPER TROUGH THAT IS FORECAST TO COME EAST

FROM THE WESTERN STATES MAY HAVE A MORE WINTRY FACE FOR OUR REGION

(IF)... COLD AIR CAN BECOME ESTABLISHED DOWN THE EASTERN SEABOARD BY

THE 25TH/26TH. A CAD PATTERN IS PRESENT WITH SOME MODEL SOLUTIONS

INCLUDING THE 234-240 HOUR OPERATIONAL EC... WITH THE HIGH IN A

FAVORABLE POSITION... AND A POTENTIAL MILLER B STORM (MAIN STORM

TRACK THROUGH THE LOWER MIDWEST... WITH SECONDARY DEVELOPMENT OVER

THE SE US). INTERESTINGLY... THAT FAR OUT... THE CAD ADVERTISED BY

THE MODELS WOULD COME WITH WARMING ALOFT (WITH THE APPROACHING

DIGGING UPPER TROUGH FROM THE WEST) STRONGLY SUGGESTING EITHER A

COLD RAIN OR SOME FREEZING RAIN IN THE TYPICAL PIEDMONT DAMMING

REGION AROUND DEC 26-27.

SUNDAY... EXPECT MOSTLY SUNNY AND CHILLY WEATHER. LOWS IN THE MID TO

UPPER 20S. HIGHS 45-52.

THE BOTTOM LINE HERE... A TREND TOWARD STORMY AND PROGRESSIVELY

COLDER WEATHER FOR OUR REGION CAN BE EXPECTED FRIDAY (DAY 5 AND

BEYOND).

&&

[NCSNOW]

JMA on board with Euro for next Saturday Low that will wind up being our makeshift 50/50 and ticket to winter weather in NC 25th-28th. Has the low futher south and much deeper which is what we are rooting for. Waiting on euro ensembles.

[ncwinterwxman]

Could you post or do you not have access?

JMA on board with Euro for next Saturday Low that will wind up being our makeshift 50/50 and ticket to winter weather in NC 25th-28th. Has the low futher south and much deeper which is what we are rooting for. Waiting on euro ensembles.

[Brick Tamland]

Well, looks like the pattern will indeed be more active. I guess some just don't believe the models regarding winter weather this far out. That is what my main question was, if others were just seeing something else on the models or just not believing what the models are advertising this far out. RAH sounds pretty confident. We had storms last night and maybe more storms coming. With that much energy around, it's not unheard of to have some winter weather a few days after storms this time of year, going from one extreme to another with such an active pattern. We don't need extreme cold for weeks on end. We just need a lot of activity and for the temps to be just cold enough when one of these systems come through. I think they system we have coming through now and the one later right before Christmas could be setting the stage for some good winter weather events.

[burgertime]

JMA on board with Euro for next Saturday Low that will wind up being our makeshift 50/50 and ticket to winter weather in NC 25th-28th. Has the low futher south and much deeper which is what we are rooting for. Waiting on euro ensembles.

Euro ENS looks like cold chasing rain to me for Christmas week then it turns warm again.

[WidreMann]

Good, that's step one towards our first winter storm.

Not with the path of that low and the crappy pattern and high heights. We aren't that close, perhaps only if by virtue of the fact that it's getting close to mid-winter.

[WilkesboroDude]

Damaging winds possible this coming Friday...I was wrong earlier to say this week would be brutal watching the long term. This week features rain chances, wind, and cold coming. Looks good.