Winter 2013-14 Pattern Discussion

[FLweather]

If you're brave enough to buy into 84 hours on the NAM it looks night and day vs. the 6z GFS at 5h for the New Years day "threat". The 6z NAM sends some energy diving into west Texas for another piece to come in on it's heels and scoot due east. Check out the differences at 84. 

6z GFS

 

6z NAM

 

 

That is like night and day but that engery being held back like that over the four corners and Mexico is suspect to me. Considering how progressive the flow has been this year.

[WXinCanton]

6z GFS is another pretty decent weekend rain event for next weekend.  Ensembles seem to be trending that way as well.   As much as I don't like to say it.  I think its sniffing out something.   Hope I'm wrong

[FallsLake]

RAH still keeping an eye on the 31st:

 

IN THE WAKE OF THE DEPARTING SYSTEM SUNDAY NIGHT...A WESTERLY WIND
WILL LEAD TO CLEARING ON MONDAY BEFORE A TRAILING CLIPPER WAVE SWING
ACROSS THE AREA FROM THE NORTHWEST MONDAY NIGHT.  THE DETERMINISTIC
GFS AND ECMWF HAVE SHOWN RUN-TO-RUN DIFFERENCES REGARDING HOW MUCH
MOISTURE ACCOMPANIES THE WAVE OR IS GENERATED BY ITS FORCING...BUT
ONLY A COUPLE GEFS MEMBERS SHOW MEASURABLE PRECIP OVER CENTRAL NC.
IT SEEMS THE FORCING WILL BE STRONG ENOUGH FOR AT LEAST A CHANCE OF
FLURRIES...BUT GIVEN THE LACK OF MODEL AGREEMENT...WE WILL LEAVE THE
FORECAST DRY FOR NOW.

 

From what I've seen on the models I'll surely hope for more but look for flurries at this point.
 

[tnweathernut]

I'm really interested in what the Euro ENS might be seeing.

Me too, looks really good the entire run

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[franklin NCwx]

I'm really interested in what the Euro ENS might be seeing.

what timeframe?

[Cold Rain]

Any sign of a sustained -NAO on the Euro ens? Or is it still oscillating either side of neutral?

[Lindsaywx]

what timeframe?

3rd-5th

[Cold Rain]

Yep, all the indexes appear to be heading in the right direction in the LR. But instead if seeing cold on the models 10+ days out! it looks warm. Of course, this is on the operationals only. I haven't looked at the ensembles yet. And the CFS for January looks cold in the east.

 

Well, apparently the images on the CPC site are not actually updating.  If you click on them, which I did not before my previous post, you get the updated view, which of course shows the opposite of basically every thing in bolded (with the exception of the AO, which is still predominately forecast to go negative).

 

At least the MJO looks like it might head into phases 7-1, albeit weakly, unless those images aren't updating either.

[SnowNiner]

I think right after new years is our only chance for a while.  After new years, the blocking gets really weak/neutral/positive.  The PNA also wants to go negative neutral. 

 

I'd be a bit more excited about 1/2 if we had a taller western ridge/+PNA.  The ensembles continue to hint at SOMETHING at this time frame, but the PNA is pretty neutral then.  It seems we've got a trough but it's not very sharp, so I'm not sure how much good of a spin up we can get. 

 

[franklin NCwx]

3rd-5th

for a storm? It really has nothing for a surface reflection.

[tnweathernut]

Any sign of a sustained -NAO on the Euro ens? Or is it still oscillating either side of neutral?

It's certainly not a traditional look for a -NAO, but the ensembles provide a weak (very weak) west based -NAO briefly that begins shortly after New Year and run through the 4th, before heading back weakly positive.  The eastern based NAO is weakly to moderately positive (SD from 1 to around 2) for the same time period.  These are from the Euro ensemble at 0z.

[WxJordan]

The chance of some sort of wintry weather on New Years Eve; however, it does depend on how the area of voriticty moves out of the desert southwest.

 

As posted above, there is stark differences on what will happen with the trough as it progresses eastward. The GFS actually cuts off a piece of energy in Mexico. This solution gives a weaker overall system with little impacts on our weather. The NAM holds this system together, which would give us at least a chance of some sort of wintry weather near the New Year.

 

But in the immediate future, we have another big time rain threat for Saturday through Sunday. Some areas, once again, will see anywhere from 1-2 inches of rain, with higher amounts likely in some areas. This could cause another round of flooding in some areas of the southeast United States.

 

Into the New Year, things do not look great for wintry weather. The NAO does not want to behave at the moment. The AO finally decided to go negative, and a slightly positive PNA is developing. We do appear to get shots of cold air through the extended period; however, no arctic air mass appears to be building down for more than a day or two.

[franklin NCwx]

Any sign of a sustained -NAO on the Euro ens? Or is it still oscillating either side of neutral?

no, no its basically neutral with maybe the slightest lean negative but basically neutral. If you look at the 500 anomaly charts it does keep higher heights over western Greenland Davis straits area. The ao appears to stay negative.

[Cold Rain]

It's certainly not a traditional look for a -NAO, but the ensembles provide a weak (very weak) west based -NAO briefly that begins shortly after New Year and run through the 4th, before heading back weakly positive.  The eastern based NAO is weakly to moderately positive (SD from 1 to around 2) for the same time period.  These are from the Euro ensemble at 0z.

no, no its basically neutral with maybe the slightest lean negative but basically neutral. The ao appears to stay negative.

 

Thanks guys.  That sounds about right.  The -NAO forecast that DT was harping on seems to be in trouble, while the OPI garbage has been functioning beautifully so far.

[burgertime]

12z NAM is a good lesson why the NAM is craptaculier at 84 hours out. This run looks more like the GFS early on with the energy out west that would hit us Jan 1/2. Energy is more positively tilted and faster on this run of the NAM @60. 

[franklin NCwx]

12z NAM is a good lesson why the NAM is craptaculier at 84 hours out. This run looks more like the GFS early on with the energy out west that would hit us Jan 1/2. Energy is more positively tilted and faster on this run of the NAM @60.

its leaving a piece out in the southwest too.

[burgertime]

its leaving a piece out in the southwest too.

 

It's almost trying to link them up in a loose fashion out to 75 and it has some northern energy screaming in which could juice up whats coming into the SE. Either way too positively tilted. I'll be in a few days it ends up lining up well with the GFS but who knows? 

[tnweathernut]

https://twitter.com/raleighwx/status/416554712238813184

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[WxJordan]

The NAM is trying to develop some very light wintry precipitation over western NC, nw GA, and through Mississippi and Alabama. This precipitation would be very light and would probably not accumulate; however, there is something else that should be monitored. The front that is going to come through Sunday will probably stall somewhere off the coast due to the upper level ridge in the Atlantic Ocean. The NAM is positioning the front farther west than the GFS, which is definitely possible. If the front stalls far enough west, this could help to cause a surface low to develop near the Gulf Coast as the upper level energy dives down. This will be something to monitor over the next few model run to see if the front stalls and if this upper level energy can dive far enough south.

[franklin NCwx]

https://twitter.com/raleighwx/status/416554712238813184

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he does see the individuals so that is encouraging.

[burgertime]

The NAM is trying to develop some very light wintry precipitation over western NC, nw GA, and through Mississippi and Alabama. This precipitation would be very light and would probably not accumulate; however, there is something else that should be monitored. The front that is going to come through Sunday will probably stall somewhere off the coast due to the upper level ridge in the Atlantic Ocean. The NAM is positioning the front farther west than the GFS, which is definitely possible. If the front stalls far enough west, this could help to cause a surface low to develop near the Gulf Coast as the upper level energy dives down. This will be something to monitor over the next few model run to see if the front stalls and if this upper level energy can dive far enough south.

 

Yea big question will be is the NAM seeing what the GFS isn't? That energy coming off the backside looks encouraging. What is not encouraging is as usual they huge changes you see from one run to another in the LR of the NAM. Seems like it basically caved to the GFS this go round. However does the 12z GFS hold something different up it's sleeve this go round? I hope so. 

[packbacker]

he does see the individuals so that is encouraging.

Over half the 50 members had accumulating snow for central NC.

[NEGa]

 I'd rather have 4" of sleet than 10" of snow. And I got what I wanted in 2/1979 and 1/1988! They have about the same water content but 4" of sleet probably would stick around longer.

i was in athens for the 79 sleet storm. most sleet i had ever seen til then and have never seen 4" of sleet after lol.  it was great for sledding and hard to walk in.  it covered everything, including the streets.  and we were out of school for a week...it just wouldnt melt.  then when it started to melt it would refreeze over night into solid ice.  awesome!!!

 

as to which i would prefer, jeesh i dont know.  that was one heck of a sleet storm, and that much sleet looked white, not like when you get a little sleet.  10" snow is also awesome.  i would take either in a heartbeat haha

 

edited to add:

 

 

 

So true. Thats what I don't understand why so many people look at the 240+ hour runs. They ultimately set their selves up for a huge dissappointment in the long run.  The weather is too chaotic to put much stock into models 150 hours out. Now I could see if there is strong agreement if something shows between 200-240 and holds steady sort of like early Nov... but recently its not been like that. 

 

But we all need to get through this weekends inch plus rainstorm and possibly 12/31 before looking further ahead.

 

i agree - even though my temps over the weekend sat. night went up a bit from mid 30s (which always means *possible* in my mind haha) looks like we have some things to watch coming up that can be trackable and not way off in the future.  as for 12/31 and 1/2 well jeesh they are within a few days of each other.  that signals me that there is definitely something that may be brewing around the end of the year (a week away) and having something to watch is better than the last couple of years have been

[BullCityWx]

he does see the individuals so that is encouraging.

 

That's exactly what i was curious about. A flat system scooping up GOM moisture is about the only way we can get a winter storm in this pattern.

[BullCityWx]

Over half the 50 members had accumulating snow for central NC.

 

Nice!

[NEGa]

That's exactly what i was curious about. A flat system scooping up GOM moisture is about the only way we can get a winter storm in this pattern.

 

yes it is, and i can remember quite a few times this happens (altho i was much younger and no internet but this was the set up from what i recall).  we dont want it too strong to have storms on the GOM zap out moisture inflow and bring in warmer air.  temps cold enough moisture moving through and things get interesting in the se

[metalicwx366]

Well, apparently the images on the CPC site are not actually updating. If you click on them while I did not before my previous post, you get the updated view, which of course shows the opposite of basically every thing in bolded (with the exception of the AO, which is still predominately forecast to go negative).

At least the MJO looks like it might head into phases 7-1, albeit weakly, unless those images aren't updating either.

Yeah, the updated Teleconnections for today is meh. PNA did a complete flip from yesterday. The GFS decide to keep the +PNA though. NAO is neutral to positive. The AO on the other hand, some ensemble members really want to send it strongly negative.

[dsaur]

i was in athens for the 79 sleet storm. most sleet i had ever seen til then and have never seen 4" of sleet after lol.  it was great for sledding and hard to walk in.  it covered everything, including the streets.  and we were out of school for a week...it just wouldnt melt.  then when it started to melt it would refreeze over night into solid ice.  awesome!!!

 

as to which i would prefer, jeesh i dont know.  that was one heck of a sleet storm, and that much sleet looked white, not like when you get a little sleet.  10" snow is also awesome.  i would take either in a heartbeat haha

 

edited to add:

 

 

 

i agree - even though my temps over the weekend sat. night went up a bit from mid 30s (which always means *possible* in my mind haha) looks like we have some things to watch coming up that can be trackable and not way off in the future.  as for 12/31 and 1/2 well jeesh they are within a few days of each other.  that signals me that there is definitely something that may be brewing around the end of the year (a week away) and having something to watch is better than the last couple of years have been

The model are just seeing shapes within the mist beyond 3 days, and even if things seem to coalesce at 3 or under, that often change in the next run.  I think the next storm is coming, and it'll be a surprise.  Best just focus the gaze from 3 days out, and in from there, then look for some agreement in the big two.  This isn't the pattern for a big storm to show up 8 days away and ride all the way in as depicted...yet.

[tnweathernut]

Surprised you guys aren't talking about the deepening suppressed low in the gulf on the 12z.  Very suppressed at this point, and still 7 days away, but still looks like a nice potential time frame to keep an eye on.

[franklin NCwx]

Changes on the gfs again. If we can get the wave to dig more and sharpen quicker we can be in business.