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Winter 2014-2015 Pattern Discussion Thread I

LithiaWx

By LithiaWx,
in Southeastern States

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packbacker

packbacker

Posted
Posted

Agreed.  I'm on board that we "should" be rocking cold and stormy in Janaury per the analogs.  But around December 20 if there's no relief in sight on the long term ensembles, I'm going to start raising my cliff diving status to defcon 2.  By then I would hope to see some ridging starting to develop at the poles and toward greenland. 

 

LOL, I might wait a little longer than that, if by Jan 1 things don't look better then it might be every man for himself...have a feeling things don't really get cold/stormy for us until mid-Jan, but do think things get a little better end of this month.

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packbacker

packbacker

Posted
Posted

 

WB 45 day CFS model run has been spitting out colder temps after the 20th for a few days now...here is a 10 day snapshot, the next 10 days is even colder...

post-2311-0-32129300-1417627781_thumb.pn

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Jon

Jon

Posted
Posted

 

 

 

Thanks guys.  I feel a bit better now.  December has always been sort of the wildcard, though that point has been made more strongly lately...now that a bad pattern is here to stay.  I feel good about the analogs, but I hate sitting here at the beginning of the month not being able to realistically expect a change for anywhere between 3-6 weeks.  Analog cold is good and all, but it doesn't put any frost or snow on the ground.  If we don't start to see some meaningful changes show up in the LR guidance soon, I'm afraid December might turn out not to be the only wildcard month this winter.

 

Here is the CFS for January.  I will readily admit that I discarded what it was showing for December, based on how poorly it performed for November.  But if this type of output is still being generated mid-month, I think there is a legitimate cause for concern for January.

 

attachicon.gifCFSv2_NaT2m_20141203_201501.gif

Like I mentioned, I'll wait until the 16th to cancel the last half of December including Christmas. So I'll wait to see that change in the guidance. Before, everyone was screaming torch for the entire month. Now people are saying we'll end up normal/near normal, no torch, cold but definitely not snow (which I don't disagree with)...but we'll see these opinions change as the models start showing new ideas mid month. I feel like this happens most years. We never have a killer December as people have already mentioned, so we need to temper our expectations.

 

Now for the CFSv2...I think what you posted is based off initial conditions Dec00z1-00z3rd, which I don't know how you can worry about January based off of those IC's, it'll change again tomorrow and the next day, then the next.

 

Check this out. Last 25 runs 2mT for January, mainly, look what's showing up after the Dec 1st. These are monthlys ending Dec 2nd, it hasn't updated to Dec 3rd on Wxbell but my point is to look at the trend and averaged runs over more days.

R0KzRj7.jpg

 

Now here's the average of those 4x daily runs over 7 days

GWj6QTe.png

Then the last 3 days

DUStiWJ.png

1 day

KGO33Hz.png

 

CFSv2 sub-weekly run for today: -AO, -NAO, +PNA through Jan 1st. -NAO goes negative just before Christmas.

 

BTW: Snow Depth maps for the CFSv2 sub-weekly show snow well into the SE (meaning a swath on the gulf coast states) on 3 out of 4 members, valid 18Dec to 28Dec and some big fun for NC late month, FWIW (take with a grain of salt)

 

FYI: Ryan Maue of WxBell gave permission to his members to post a lot of maps, except some Euro specific ones that make his site specific. Mods message me if you need proof before hitting the X on my post if you see some wxbell images throughout the season, thanks :)

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FallsLake

FallsLake

Posted
Posted

That's more like it, Pack!  Let's get some more images like that in here, stat!

I agree that we must be patient. Also as many on here have noticed, low level temps are not as bad as the upper air temps would indicate. Nothing really cold but I could see many of us averaging normal until the cold comes the end of the month. **something to track while we're in this type of pattern.  

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packbacker

packbacker

Posted
Posted

Don't look now, but I think the DOC is going to have a nice trof over the E early next week. I see the early signs of it on the new run coming out. 

 

It's gone insane, I think the Euro was bored with what it's been spitting out so it decided to shake things up a bit.  The NE gets hammered not once but twice in the next 7 days.

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deltadog03

deltadog03

Posted
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I don't think we see snow out of that...but hell, look at it and gfs and tell me if there is any similarity.  lol  GFS will STRUGGLE mightily this year.  It can not handle all the energy that comes with an el nino ish winter.  EURO will struggle as well, but not nearly as bad.

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Cold Rain

Cold Rain

Posted
Posted

I agree that we must be patient. Also as many on here have noticed, low level temps are not as bad as the upper air temps would indicate. Nothing really cold but I could see many of us averaging normal until the cold comes the end of the month. **something to track while we're in this type of pattern.

 

 

Some positive signs coming to light in the long range. Anyone getting antsy now needs to toughen up a bit. JMO.

Good posts.  I will go eat some Jack Link's beef jerky now.

 

Jon had a good post too.  Thanks for the info and maps, Jon.

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Jon

Jon

Posted
Posted

 

 

Good posts.  I will go eat some Jack Link's beef jerky now.

 

Jon had a good post too.  Thanks for the info and maps, Jon.

No problem...

 

Euro flips, brings -5C 850mb temps to North Florida on 06z Dec 10th. Hopefully it's not on drugs.

Edit: actually, it had -5's in florida 12z yesterday. Nvm. Euro didn't exactly flip, just showing more chances for DCA north.

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FallsLake

FallsLake

Posted
Posted

Looking closer at the 12z GFS, the upper pattern definitely sucks in the LR but ground temps are actually on the cool side. There are many days in the LR where highs are only in the 40s for many. Now to be fair, there are very few lows below freezing but the point is we in the SE are possible looking at a below normal (average temp) December. 

 

http://www.twisterdata.com/

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Jon

Jon

Posted
Posted

Funny how the cfsv2 is wrong/ sucks when it shows warm, now it's everybody's last hope, lol

I don't know about that. It might be because it's the only extra long range model beside the Euro monthly that we can look at. Also, it spits out a lot of data and runs so if you look at the 4 runs averaged over a single day every day, you're going to say the CFSv2 sucks. It's only guidance! Trust me if the averaged runs of 7 days wasn't showing cold over the Hudson Bay my post would look a lot different.

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packbacker

packbacker

Posted
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Funny how the cfsv2 is wrong/ sucks when it shows warm, now it's everybody's last hope, lol

 

Whoever says it's always wrong is wrong themselves.  I went back and looked at the last 3 winters (9 months) of monthly predictions and it missed one of those 9 months.  The other 8 it hit.  It did miss November, missed it badly but so did the mighty Euro/ENS/Monthly. The previous few months it did fairly well.  It's going to do well for Dec, maybe not in the SE, but it will do well with a warm Canada and warm western/central US.  We are by no means going to be cold, but we (SE) will be above average for temps the first 20 days of the month, just depends on how rainy we are on how much we are over.  I could see us be below normal for the last 10 days of Dec and we end finishing neutral, but that's a long ways off.

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griteater

griteater

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Posted

Whoever says it's always wrong is wrong themselves.  I went back and looked at the last 3 winters (9 months) of monthly predictions and it missed one of those 9 months.  The other 8 it hit.  It did miss November, missed it badly but so did the mighty Euro/ENS/Monthly. The previous few months it did fairly well.  It's going to do well for Dec, maybe not in the SE, but it will do well with a warm Canada and warm western/central US.  We are by no means going to be cold, but we (SE) will be above average for temps the first 20 days of the month, just depends on how rainy we are on how much we are over.  I could see us be below normal for the last 10 days of Dec and we end finishing neutral, but that's a long ways off.

 

That's pretty strong Pack.  To clarify, I think there are a couple things at play here.  I believe what you are referring to with respect to CFS verification the past 3 winters is taking the last day of the month to project the following month...so, the CFS forecast for Dec taken on Nov 30, is that correct?  As viewed here - http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/

 

Whereas tracking a CFS January forecast four times a day in early December isn't going to be very fruitful.

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packbacker

packbacker

Posted
Posted

That's pretty strong Pack.  To clarify, I think there are a couple things at play here.  I believe what you are referring to with respect to CFS verification the past 3 winters is taking the last day of the month to project the following month...so, the CFS forecast for Dec taken on Nov 30, is that correct?  As viewed here - http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/

 

Whereas tracking a CFS January forecast four times a day in early December isn't going to be very fruitful.

 

Correct, I look at the last 1-4 days of the run before the month ends, I don't even look at the CFS until mid-Dec for what Jan brings.  But you can see trends as the month moves along, if you take the CFS model FWIW it can be useful.  It's not the end all be all but if your looking at the last couple of runs of Nov and see that it's calling for a conus torch and the argument is that it always busts then your wrong.  Well I guess you could argue the CFS is always wrong by only looking at the first runs of the month but with any model as things get closer its more right than not.

 

You see what HM posted in the MA thread?  That should calm the weenie meltdowns that have been going on today across all regional forums.

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Webberweather53

Webberweather53

Posted
Posted

Regardless of wintry wx, the subtropical jet looks like it will turn things up a notch over the coming week (already a 70-80 knot+ jet streak showing up in the GFS ensembles, pretty impressive). You should also note the distinct split stream flow accompanying the massive & persistent trough over the Aleutians/Gulf of Alaska, a textbook East Based El Nino pattern for Dec. However this should be relatively temporary, but even in such a set-up it is most certainly not a "dumpster fire" as some have falsely assumed for the southeastern US. The invigorated subtropical jet will keep our temperatures in check & more seasonable but we could see above normal temps from time to time, however it simply doesn't compare (vs climo. averages) to what our neighbors to the north & west will experience.

 

Given the placement/latitude of the ridge over central N America & the aforementioned momentary analogs, there is likely to still be plenty of mischief within the subtropical jet (also denoted by the pronounced dip in the heights over the northeastern Pacific) that will keep our weather at least somewhat interesting ...

 

test81.gif

 

hzCftC2w4G.png

 

& I suspect the progression convectively enhanced phase of the CCKW well into the Pacific & Western Hemisphere may be to blame here & Dr. Ventrice concurs, igniting the already active east-central Pacific...

gfs-ens_uv250_namer_31.png

 

This CCKW may be causing a punctuated uptick in the southern stream reminiscent to that of the phase 8-1 MJO which in NDJ is quite wet in the southeastern US

 

combined_image.png

Knowing how El Nino winters behave I see no reason to be worried or frustrated about wintry wx in December, in fact, seeing snow before the new year is IMO a bonus. I've noticed (for reasons I've yet to figure out) that in general, El Ninos have a tendency to pack in their big snows in the heart of the winter & display a very distinct peak in activity in Jan & Feb. While La Ninas are significantly more even tempered & peak in March. I looked through the NC Winter Storm Database that goes back to 1958 and divided the the late Oct-Apr period into 5 day increments (to capture the beginning & end of the months, instead of a week where I would have to deal w/ a considerable amount of overlap) & normalized the data to account for the difference in the # of + vs - ENSO events, & the 5 day blocks at the end of the month. (I took out the NW flow events, esp. later in the record, which may have been undersampled/reported in the antecedent decades & I plan to eventually present some of this data over the coming few weeks regarding Equatorial VP & NC Winter storms in seeing the robust connection I observed w/ 30-60E 200hpa VP.). As I mentioned above, you should see that El Nino winters esp. tend to have a more pronounced peak in wintry wx in the heart of the winter vs La Ninas from late December through mid Feb & a minor secondary peak is evident in April. The largest advantage in winter storm frequency w/ La Ninas tends to be around the edges of winter, particularly in early-mid December & March

ENSO-NC-Winter-Storms-5-Day-Increments-1

 

Similar results were attained when I looked @ all the NESIS snowstorms as indicated by Kocin & Uccelini. In order to level the playing field, I divided the # of La Nina events (22) over the # of events in other ENSO categories & then multiplied that by the # of storms in each ENSO category, hence the decimals...

Monthly-NESIS-Normalized-Snowstorms-El-N

 

 

 

Monthly-NESIS-Snowstorms-ENSO-ENSO1-1024

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Jon

Jon

Posted
Posted

Correct, I look at the last 1-4 days of the run before the month ends, I don't even look at the CFS until mid-Dec for what Jan brings.  But you can see trends as the month moves along, if you take the CFS model FWIW it can be useful.  It's not the end all be all but if your looking at the last couple of runs of Nov and see that it's calling for a conus torch and the argument is that it always busts then your wrong.  Well I guess you could argue the CFS is always wrong by only looking at the first runs of the month but with any model as things get closer its more right than not.

 

You see what HM posted in the MA thread?  That should calm the weenie meltdowns that have been going on today across all regional forums.

Can you link? I can't find it other than the SST anomaly analogs at 500mb? Is that it?

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Brick Tamland

Brick Tamland

Posted
Posted

Yep Robert and JB both have said for weeks on their websites that it was coming that models has not picked up on it.  

 

A lot of mets have said the first half of December shouldn't be much of anything, and the fun won't start until the second half to the end of the month. This month is just setting the stage for the rest of winter.

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