December pattern/forecast thread

[powderfreak]

2 minutes ago, Typhoon Tip said:

Firstly, that product doesn't mean it's time to jump on anything...

this has been explained to you ... a half dozen times, but I will again simply because I'm bored at the moment.  That means there is at or less than a 40 % chance for below normal temperatures - which in plain English means the assessment has an ~ 60 % chance of N/S; moreover, that region barely includes New England. 

in other words, the signal's week.  It's actually more likely to dapple anomalies on either side of 0 SD throughout that area - perhaps a few more negatives just to resist being pissy about it. 

He knows, he's one of of the most vocal against probabilistic forecasts.  If that map was red he'd be all over the awfulness of probablalistic forecasting.

[Damage In Tolland]

2 minutes ago, powderfreak said:

He knows, he's one of of the most vocal against probabilistic forecasts.  If that map was red he'd be all over the awfulness of probablalistic forecasting.

You seem to think you are me?

[Typhoon Tip]

2 minutes ago, powderfreak said:

He knows, he's one of of the most vocal against probabilistic forecasts.  If that map was red he'd be all over the awfulness of probablalistic forecasting.

...someone needs to give the GFS la-la range that same pipe CDC is smokin' ...

[JC-CT]

...someone needs to give the GFS la-la range that same pipe CDC is smokin' ...

Who doesn't love a good SE ridge

[Damage In Tolland]

LOL posting an 18z GFS map. I mean come on now..Do folks really even look at that?

[OceanStWx]

Just now, Damage In Tolland said:

LOL posting an 18z GFS map. I mean come on now

I thought mets at least had to consider it now. Or is that just the 12z/00z runs?

[JC-CT]

LOL posting an 18z GFS map. I mean come on now..Do folks really even look at that?

Yes, 18z is what is wrong with it. A 12z 384 hour map would be perfectly acceptable...

[Damage In Tolland]

1 minute ago, OceanStWx said:

I thought mets at least had to consider it now. Or is that just the 12z/00z runs?

Would you take it or an ensemble map?

[OceanStWx]

7 minutes ago, Damage In Tolland said:

Would you take it or an ensemble map?

What do you think at day 16?

[Damage In Tolland]

5 minutes ago, OceanStWx said:

What do you think at day 16?

Exactly 

[USCAPEWEATHERAF]

GFS produces snow for CHH, from December 4th 12z through December 7th 00z, OES it looks like with a delta t of 18C.

[Hazey]

The 6z GFS is looking a tad better in the medium range. I know there is work to do but I'd rather have something trend better as we get closer in than trend worse. We'll see if it's catching on rather than a blip run.

[Damage In Tolland]

Details still convoluted, but two s/w's Sunday night and again Tuesday look like they'll provide some light snow/ snow showers which if it works out right can drop an inch in places

[powderfreak]

12 hours ago, Damage In Tolland said:

You seem to think you are me?

Sorry just had you confused with someone else.  I forgot you are always preaching the values of probabilistic forecasts and how we need to take the industry in that direction to show uncertainty ;).

There's a 33% chance I'm right, a 33% chance I'm wrong, and a 33% chance I'm asking the wrong question.

[CoastalWx]

The Monday thing looks better on the euro, but the GFS isn't really biting yet. Still sort of a low chance look there. After that, the question is what happens to that Mexican s/w. No walls built here, that ejects NE. The 6z GFS gets the s/w northeast and causes a SWFE more or less. It's much more robust than the euro which ejcts the s/w northeast, but develeops strung out low pressure offshore and doesn't effect New England much at all.

[Damage In Tolland]

Great signs continue ., Today is it for warmth other than a day ahead of a cutter or something 

 

[SnowHole413]

My guess on the month in normal to -1 BN temperatures and above average precipitation. I just hope a decent storm track can set up after the 10th. Either way I think most of us will take our chances this December given the last 2 blow torch Decembers.

[dryslot]

I thought the 06z GEFS looked pretty good overall

[Typhoon Tip]

Damn ... if there were ever any sort of positive to take away from a 1859, Carrington Event, it's that the random re-posting of Tweets by ad infanitum Mets by Kevin would finally be forced to stop.

Yes...it is true. The rest of humanity would suffer a catapult cataclysm that whiplashes "civility" back to the dark ages...replete with anarchistic break-down of social order, and inevitable population correction, disease, starvation, basically ... an incalculably horrific dystopian reality - sure. But wait!  At least we could all rejoice in the knowledge that 0 percent of our eye energy will ever have to be spent again passing over some weather goober's random knee jerk reactionary optimism over a modeling product cycle, pulled undoubtedly out of context in order to push across sensationalizing another goober's desired sensible weather. 

I don't know about you'all but it almost seems worth it to me... almost. 

[Typhoon Tip]

yeah ... all that .. .and, the 00z operational GFS and the subsequent 06Z broke continuity with certain demonstrability and that's the real take away. 

up through and including 12z yesterday, all the guidance varied on timing and spacing of features (and pretty much still do), but somewhere in there... there was a modicum of two basic events to monitor:   Monday-Tuesday, then the monster in the Lakes/NP region later in the week... both of which had confidence shaken. 

Frankly, through it all I have never liked the fact that if you take a line and draw it from roughly Virginia to midriff California across the nation, and then look south, everywhere south of that line the atmosphere is too tall.  

Heights don't seem to want to come down off summer south of that line.  What's happening everywhere is that the seasonal depth of the polar vortex is trying to deepen ... press in lowering heights from the N like normal. but that is causing an average of 9 to 11 isopleths at any given time, packed together regardless of, and circuitously wending around, features in the flow.  too much gradient everywhere and the individual systems can't mechanically operate on the flow as effectively.  the whole of the PV ends up a storm.  

yet another way to look at it.. the ridges are flattish ...possibly physically caused to do so by the former at that. either way, determinism pretty much doesn't exist. 

anyway, the idea of a plumbed trough into the heartland region, with steep slopes on either side just might not have ever been a good fit for that background canvas.  Seeing the GFS get flat and more progressive with that big system for latter next week both perhaps fits better with a screaming hemisphere, but it also changes the outlook considerably.  one ...confidence is rattled of course, but the residue that falls out of that sifting is that it's a new trend that is not only supported but who knows when it stops. in fact, it's almost like the two event idea is setting/set sail and it's really more like a single even that strung out. 

[Hailstoned]

27 minutes ago, Typhoon Tip said:

Damn ... if there were ever any sort of positive to take away from a 1859, Carrington Event, it's that the random re-posting of Tweets by ad infanitum Mets by Kevin would finally be forced to stop.

Yes...it is true. The rest of humanity would suffer a catapult cataclysm that whiplashes "civility" back to the dark ages...replete with anarchistic break-down of social order, and inevitable population correction, disease, starvation, basically ... an incalculably horrific dystopian reality - sure. But wait!  At least we could all rejoice in the knowledge that 0 percent of our eye energy will ever have to be spent again passing over some weather goober's random knee jerk reactionary optimism over a modeling product cycle, pulled undoubtedly out of context in order to push across sensationalizing another goober's desired sensible weather. 

I don't know about you'all but it almost seems worth it to me... almost. 

Right on. (and right over his head...)

[Damage In Tolland]

45 minutes ago, dryslot said:

I thought the 06z GEFS looked pretty good overall

Tip didn't. As usual.. when things look bleak he portends the hero role and tries to make lemons out of lemonade.. but when things look good he masterminds ways for things not to look good. I think we all recognize this behavior by now.

Gefs have looked good for several cycles now and have nodded the way of the EPS 

[Typhoon Tip]

7 minutes ago, Damage In Tolland said:

Tip didn't. As usual.. when things look bleak he portends the hero role and tries to make lemons out of lemonade.. but when things look good he masterminds ways for things not to look good. I think we all recognize this behavior by now.

Gefs have looked good for several cycles now and have nodded the way of the EPS 

this might or might not be true, but ... unfortunately, i never said the 06z GFS didn't "look good" 

in fact, i didn't qualify in that regard at all - good or bad. 

dude, how do you sustain a successful sales career, home, family and all the usual tangible and intangibles that construct a middle ager's life with that particular reading comprehension skill of yours? 

that question in its self should be a baffling puzzle to modern science.

if anything, the 06z GFS was better for what the local denizens of social weather media want...because as i said, " it is more strung out" which anyone with a saw dust ort of mental proficiency knows in this field, that means warm air doesn't penetrate as far N. 

 

[ORH_wxman]

The analogs for after Dec 10 are starting to become a lot colder/wintry...if you recall a few days ago, I had mentioned how mixed the analogs were. They have improved for the better. However, given we are still about 10 days out, obviously caution should be applied.

 

Euro ensembles at D10 below:

 

 

 

 

 

 

 

Objective analogs from the GEFS below....you can see the pattern is very similar on both sets of guidance:

 

 

 

 

We see years like 1983, 1995, 1966, and 1977 showing up...and even the non-epic Decembers are no longer horrendous (we don't see 1994 or 1998 anymore), more middling like 1956, 1996, and 1968. We'll see as we get closer...the ensembles have been a little bit shifty with the block folding N of AK/Bering and that is an important feature.

 

 

[snowgeek]

CPC's increased chances of a warm northeast December seems to be riding on 
strong cutters during the beginning of the month.  If the flow is flatter 
with more strung out systems, they will probably be wrong.  

PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 
300 PM EST WED NOV 30 2016 
 
30-DAY OUTLOOK DISCUSSION FOR DECEMBER 2016 
 
THE UPDATED MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR DECEMBER 2016 
ARE BASED ON THE LATEST DYNAMICAL MODEL GUIDANCE, WPC TEMPERATURE AND 
PRECIPITATION FORECASTS DURING THE FIRST WEEK OF DECEMBER, THE CPC 6-10/8-14 
DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, AND CPC'S EXPERIMENTAL WEEKS 3-4 
TEMPERATURE AND PRECIPITATION OUTLOOKS. SINCE THE FUTURE MJO EVOLUTION AND ITS 
POTENTIAL INFLUENCE ON THE EXTRATROPICAL CIRCULATION PATTERN ARE NOT CERTAIN 
DURING THE NEXT MONTH, THE MJO WAS NOT CONSIDERED A MAJOR FACTOR IN THE REVISED 
OUTLOOKS. 
 
LARGE CHANGES WERE NECESSARY IN THE TEMPERATURE OUTLOOK, DUE TO A HIGHLY 
AMPLIFIED RIDGE FORECAST OVER THE BERING SEA WITH A DOWNSTREAM AMPLIFIED TROUGH 
ACROSS THE CONTINENTAL U.S. LIKELY PERSISTING THROUGH THE FIRST HALF OF 
DECEMBER. THIS LONGWAVE PATTERN YIELDS A MUCH COLDER OUTLOOK ACROSS THE 
CONTINENTAL U.S. AND ALASKA THAN WHAT THE DYNAMICAL MODEL GUIDANCE INDICATED AT 
MID-MONTH. TEMPERATURES ARE EXPECTED TO AVERAGE 5 TO 10 DEGREES F, OR MORE, 
BELOW NORMAL ACROSS MUCH OF THE WESTERN U.S. DURING THE FIRST WEEK OF DECEMBER. 
ALSO, POSITIVE ANOMALIES IN SNOW COVERAGE CURRENTLY EXIST ACROSS THE GREAT 
BASIN AND INTERMOUNTAIN WEST, RAISING CONFIDENCE IN BELOW-NORMAL TEMPERATURES 
FOR THESE AREAS. THEREFORE, BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF 
THE WESTERN U.S. IN THE REVISED OUTLOOK. THE HIGHEST PROBABILITIES FOR 
BELOW-NORMAL TEMPERATURES ARE FORECAST FOR THE NORTHERN ROCKIES AND NORTHERN 
HIGH PLAINS WHERE ARCTIC HIGH PRESSURE IS EXPECTED TO RESULT IN THE LARGEST 
NEGATIVE TEMPERATURE ANOMALIES DURING EARLY DECEMBER AND BELOW-NORMAL 
TEMPERATURES ARE MOST LIKELY TO PERSIST INTO THE SECOND WEEK OF DECEMBER. 
INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES EXTEND EAST TO THE GREAT PLAINS 
WHERE THE CPC 6-10/8-14 DAY OUTLOOKS FAVOR BELOW-NORMAL TEMPERATURES AS 
MODIFIED ARCTIC AIR IS FORECAST TO AFFECT THIS REGION AT LEAST EARLY IN THE 
MONTH. FORECAST CONFIDENCE IS LOWEST ALONG THE EAST COAST DUE TO VARIABLE 
TEMPERATURES FORECAST DURING EARLY DECEMBER, FOLLOWED BY MORE UNCERTAINTY IN 
THE LONGWAVE PATTERN ACROSS EASTERN NORTH AMERICA LATER IN THE MONTH. SINCE THE 
EAST COAST IS EXPECTED TO RESIDE ON THE RELATIVELY WARM SIDE OF MULTIPLE LOW 
PRESSURE SYSTEMS TRACKING ACROSS THE EAST-CENTRAL U.S. EARLY IN THE MONTH, A 
SLIGHT TILT IN THE ODDS FOR ABOVE-NORMAL TEMPERATURES IS FORECAST FOR THE 
NORTHEAST AND PARTS OF FLORIDA. 
 
BASED ON SHORT-TERM AND CPC'S 6-10/8-14 DAY PRECIPITATION OUTLOOKS, INCREASED 
CHANCES FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS THE PACIFIC 
NORTHWEST, NORTHERN GREAT BASIN, AND NORTH-CENTRAL ROCKIES/HIGH PLAINS. ARCTIC 
HIGH PRESSURE SHIFTING SOUTH FROM WESTERN CANADA EARLY IN THE MONTH IS EXPECTED 
TO ENHANCE UPSLOPE FLOW AND PRECIPITATION ACROSS THE NORTHERN AND CENTRAL HIGH 
PLAINS. DOWNSTREAM OF THE AMPLIFIED UPPER-LEVEL TROUGH EARLY IN THE MONTH, 
ABOVE-MEDIAN PRECIPITATION IS FAVORED ALONG THIS PREDICTED STORM TRACK. THE 
HIGHEST ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS SOUTHEAST TEXAS 
AND LOUISIANA WHERE THE PRECIPITATION TOTALS PREDICTED DURING THE FIRST WEEK OF 
DECEMBER ARE NEAR OR ABOVE THE DECEMBER NORMAL. THE MOST LIKELY AREA FOR 
BELOW-MEDIAN PRECIPITATION EXISTS ACROSS THE FLORIDA PENINSULA DUE TO RIDGING 
ALOFT DURING EARLY DECEMBER AND IT IS CONSISTENT WITH THE LOW-FREQUENCY BASE 
STATE. 
 
ARCTIC HIGH PRESSURE WITH ANOMALOUS NORTHERLY FLOW IS EXPECTED TO RESULT IN 
LARGE NEGATIVE TEMPERATURE ANOMALIES ACROSS MOST OF MAINLAND ALASKA AND THE 
ALASKA PANHANDLE DURING EARLY DECEMBER. BASED ON THESE LARGE NEGATIVE 
TEMPERATURE ANOMALIES, BELOW-NORMAL TEMPERATURES ARE FAVORED IN THE REVISED 
TEMPERATURE OUTLOOK. ABOVE-NORMAL SSTS CONTINUE TO FAVOR ABOVE-NORMAL 
TEMPERATURES ACROSS THE ALEUTIANS AND COASTAL SOUTHWEST ALASKA. ENHANCED ODDS 
FOR BELOW-MEDIAN PRECIPITATION PREDICTED FOR COASTAL SOUTHERN ALASKA ARE 
CONSISTENT WITH RECENT DAILY RUNS OF THE CFS MODEL AND ANOMALOUS OFFSHORE FLOW 
EARLY DURING DECEMBER. 

[Typhoon Tip]

39 minutes ago, ORH_wxman said:

The analogs for after Dec 10 are starting to become a lot colder/wintry...if you recall a few days ago, I had mentioned how mixed the analogs were. They have improved for the better. However, given we are still about 10 days out, obviously caution should be applied.

Euro ensembles at D10 below:

Objective analogs from the GEFS below....you can see the pattern is very similar on both sets of guidance:

e see years like 1983, 1995, 1966, and 1977 showing up...and even the non-epic Decembers are no longer horrendous (we don't see 1994 or 1998 anymore), more middling like 1956, 1996, and 1968. We'll see as we get closer...the ensembles have been a little bit shifty with the block folding N of AK/Bering and that is an important feature.

 

 

for winter enthusiasm, i actually like that look for contending and dealing with the SE ridge...

what's interesting about that is the 100,000 foot sort of perspective on things. the PNA clearly wants to maintain a negative bias, and that's probably part and parcel in why the f' ridge won't yield.  but, it seems the eastern most domain space of the PNA (the N/A sector) is trying to pinch off from the Pacific in conflict. 

not sure what comes from that, but it's certainly a start!   

but also that is a whopper -EPO block formulating up there.  it's interesting the analogs do that when the typical known event/predecessors aren't sort of lacking ...be it tropical forcing and/or MJO ...and/or torgue budget from off Asia/Siberia (although the WPO is trying to go negative so hmm). 

you know... it may be a hints and frets sort of mind game and then some Saturday morning here sooner or later we set our coffee cups down and dial into an omg moment - 

[Damage In Tolland]

GFS bows to Euro and eliminates the cutter . Turns it into interior snower mid week

[CoastalWx]

1 minute ago, Damage In Tolland said:

GFS bows to Euro and eliminates the cutter . Turns it into interior snower mid week

Euro had a cutter.

[Ginx snewx]

Low level cold, get us the cold and sh it happens. Hope this is a start of something

[Damage In Tolland]

2 minutes ago, CoastalWx said:

Euro had a cutter.

It's had it and lost it back and forth. GFS always had it. Hopefully trends continue