Monday, January 24, 2011

Model Waffling Continues. A Wet Start with Potentially A Snowy Finish on Next Event...?

We continue to have a great deal of uncertainty as we progress into the beginning of this week.  Forecasts have progressed from a crippling ice storm to major snow storm and now a major rain to snow event.  One reason that I believe we have seen such trends is because the models were beginning to realize the absence of the high up to the northeast, which will slide OTS and not provide the CAD signature that was progged earlier.  However, we now have to turn our attention over to the storm system and the ULL associated with it, which will ultimately determine who sees what based on track, strength, timing, and the features aloft. 

My thoughts at this point are that the low will track along the Gulf Coast and begin its turn through southern GA and onto the southern SC coast, heading due northeast. Throughout this period, I expect rain to spread over the Carolinas and parts of Georgia with snow beginning to develop on the backside as colder air is wrapped up into the system when the dynamic cooling kicks in.  Once the low begins to leave from the NC coast, we have an ULL that will be providing some folks with additional cooling and cause deformation banding to set up somewhere from N GA toward areas in WNC and onward.  Here in the CLT region, I believe that it will be a close call with a very sharp cutoff either just due west or east of CLT but will not guarantee our area to get into any heavy snow just yet.  I also think the track will end up being similar to the March 2009 event but perhaps a slightly more northward track this go around.  We'll see how it goes.  The conundrum with these ULLs are rather difficult to forecast and could take one for quite a spin when trying to pinpoint locations at a given time but we should have a better idea of how things unfold once we get into the later part of tomorrow with radar trends and the continuation of the nowcast models.

This is a very fluid situation we are dealing with here and chances are that whoever may be in the lucky spots now could very well not be so lucky later on and vice versa.  I still think the mountains and parts of the foothills in NC stand to see a very good chance of significant snow accumulations for their area, as well as back into eastern TN, extreme SE KY, and parts of VA.  Due east of the Apps., it's all about how that ULL behaves when it tracks through the Carolinas and of course the surface low as well.  Lots of tracking to do with this one and it will be interesting to see how it all plays out in the end.  There will be broken hearts and satisfied folks with this but at least it has been fun getting a REAL challenge for once to see how well we predict this storm.  Hope everyone (well mostly) gets what they want.  More later.  

Wednesday, January 19, 2011

Rain Exits and then Returns for Thursday Night/Early Friday. Model Madness Continues with Wintry Precip. Chances...

Hope everyone found a way to enjoy yesterday's damp and chilly conditions as we finally see this ugly mess lift away from our region across the SE for the rest of the early morning hours.  An arrival of colder air filters into the area for the rest of this week, knocking us back into the much colder temperatures for the night time period of the 20s and possible upper teens as a range of lows around Saturday.

What looked good for a possible wintry event this late week has since vanished from the modeling and looks more likely that we experience nothing but a chance for some passing showers for the Thursday night-Friday morning time frame.  Once that clears out, our attention will be toward what occurs for next week.  Based on recent data, here's the breakdown:

0z GFS:  Once more, we see another oddball job pulled off with this run.  Going out to the 120 hr at 500mb, the setup it shows is fantastic for something interesting across the SE.  The vort energy has a very healthy look to it back in the southwestern states and digs a good bit southward while progressing east.  Jumping to the 192 hr, that energy has reached central TX with a neutral trough already established and staying intact.  However, that energy gets dampened out as soon as it leaves TX and thus you see a garbage output with the surface plots not matching the upper air features at all.  This is just like the time that the NAM was having an issue matching its 700mb/omega feature with its 850mb plots for our past winter event.  At this point, I wouldn't throw away the 0z completely despite its screw up but keep an eye on the 5H level.  If we see a continuing trend with the model extending the life of the vort energy (and if the surface plot correctly reflects this), it will be something to take into consideration in the near future.

0z GGEM: This was also a great run for us.  Here the Canadian is able to handle a couple of waves of energy correctly (again at 500mb).  With the primary wave, this one moves into central TX and then travels across the southern part of MS and into central/northern AL while still remaining healthy.  In turn, upper level cooling can take place and snow becomes more likely for areas north of the surface low as it travels along the Gulf Coast.

0z UKMET:  Also comes in robust with our system but threatens areas such as the Carolinas and north GA with a damaging ice storm at the cost.  You have a 1039mb high in the NE in NY with a low at 1009mb sitting between the borders of MS and AL on Tuesday.  Places east of the Appalachians would need to watch out if this solution verified but will not wig out about it on this model.  However, the Euro says this as well but will get to that part on the next section.....

0z Euro: As stated, pretty much an eerily similar setup shown on here like the UKMET but first, I will point out what has showed up for Sunday.  Starting out at the 72 hr., our system is exiting southeastern TX and moving across the Gulf Coast strengthening some as it does so and actually spreading what looks like a bit of snow across the Arklatex area and northern MS/AL/GA.  By 96, this low has become 1000mb and curves NE after exiting FL but not hugging the coast.  However, it is close enough that areas along the SC/NC coast could get in on some snow for their area.  Any closer to or along the coast and areas further west like us will need to start watching but right now this is more of "Coastal Special" verbatim of the Euro.  QPF totals suggest nearly .70 for Wilmington (the winner) and the Pitt-Greenville Airport area with only .09 (the loser).  After this, we relax for a day before worrying about the next system to push in.  This is where the similarity between it and the UKMET comes into place, with nearly the same strength and placement of the damming high (1038mb), as well as the low:

UKMET: http://i715.photobucket.com/albums/ww152/Killerchaos7/UKMET.gif?t=1295424474
EURO: http://i715.photobucket.com/albums/ww152/Killerchaos7/EURO.gif?t=1295424476

In this case, the Euro would also suggest an icy doom for parts of the SE, with everyone starting as snow and then changing to ice as temperatures aloft warm some.  This would imply that from say NE GA to Western/Central NC would see the worst of this scenario.  I would pay special attention to the 5H with this one because if it holds on the next several runs, then we have ourselves a major problem to deal with.  I wouldn't worry about the 850s or how much moisture, but just keep an eye on the 500mb charts when you get the chance to view them.  It can easily change on the 12z and is also out to at least a week, so there is not much to worry about for now thankfully.  Could trend colder/snowier, warmer/wetter, etc. but I just can't give a definite answer until we're closer.

Overall, one can say that the trend was colder and potentially more wintry on all of the models that I just summarized.  One thing that I will say is to keep watching what happens back west with our shortwave, and pay attention to how much it digs and whether or not it stays unblemished.  That will be key as to what we in the SE could see for next week.  It will be a rough ride indeed and chances are, MUCH CAN AND WILL CHANGE between now and the next 7 days.  As always, I will keep an eye for you folks on this ever-changing situation and will get back to you all if I can.  Take care.

Saturday, January 15, 2011

Two More Dry Days. A Wet Tuesday Down the Road (Not Feeling the Icy Love Anymore). Also Watching Next Weekend's Threat...

Conditions today have felt rather nice; almost Spring-like if you will after being stuck in the 30s as highs for so long with temperatures ranging from the mid to upper 40s throughout our region and even nicer conditions as you head further south and southwest from North Carolina.  Still plenty of snow and ice left on the ground (currently have 2 or 3 inches here in Gastonia) and a bit of ice remains on the secondary roadways but traveling has substantially improved with the progressively warmer temperatures and plentiful sunshine in these areas.  Make the most of tomorrow and Monday for next week because we go downhill from here after experiencing upper 40s and lower 50s for highs over the next 2 days...

Regarding the next shot for precipitation, what was once a chance for us here in the Piedmont to get into a bit of a wintry mix during the early day Tuesday is no longer looking like a threat.  I expect any frozen precipitation to be confined to the high elevations of the NC and VA mountains, where they could see some snow and a bit of ice in the mix in spots.  The rest of us east of the Appalachians and throughout the rest of the Southeast should see rain as the primary precipitation here with temperatures getting close to 50° for some areas.  Looks like a decent hit, and despite the recent wintry weather some people could use a bit of rain so it's not all bad.

After this event, we dry out for a few days before another system comes in for next weekend.  Right now specifics are something to not worry about at this point.  Modeling has been all over the place with this one.  Some suggested another snowy hit, others a rather icy one (mainly from watching the Euro trends).  I will go ahead and say that ANYTHING is possible at this point and the modeling will NOT get a good handle on our re-developing cold pattern after this brief relaxation, so there's still some time to watch this.  Not excited about it yet but we'll keep an eye on things for everyone and let you folks know when something comes up.  For now, just enjoy the break we have from the very cold and wintry conditions, and hopefully some of you already have indoor plans when the rain comes in.  Take care and have a good evening.

Thursday, January 13, 2011

Melting Continues for Today. Still Looks Wet Next Week but Potentially Icy...

This will make it the third day today since the snow and ice fell in our area on Monday.  Temperatures have been rather cold and keeping the melting process from progressing at a faster rate.  I think as we finish today and a part of tomorrow, most if not all of the secondary roads should be safe to drive on.  I had seven individuals, including the mail man, getting stuck in my neighborhood and all of them either went back home or took the very long way to get out.  The horror of steep hills and ice...

Regarding next week, modeling continues to show a wet scenario for our region.  However, there has also been the idea of possibly some ice to deal with if the setup is correct but so far, hardly anything is showing that play out for areas outside of the Appalachians but here's the breakdown of what I've come across so far:

GFS- Tries to build a bit of a CAD signature with a 1028mb high sitting in southern Quebec but decides to make our high retreat north and east from there as a 1000mb low goes through the OV (like the 0z and 6z run did).  Therefore, the majority of the precipitation avoids us altogether and continues to stay west of the Apps. until early Wednesday and at that point, we're seeing light rain falling here.

CMC- Precipitation is able to spread into NC, but everyone east of the Apps. sees a cold rain while along and northeastward of the Apps. sees a bit of rain and ice before kicking over to all snow, especially once you get into VA's mountain range.

Euro-  It's close to having something for our area, but quickly swipes the chance of wintry precipitation in the later frames.  Around 96, we have a 1028mb high to our NE while our Gulf low is making a run for the coast around SC.  By 120 however, that high to our north is not there all the sudden to provide a healthy CAD and the low is just off the coast of NC at 1000mb and rapidly deepening just like the previous storm. Consequently, temperatures at the surface and aloft are just a tad too warm to support anything else but a cold rain.  If we had kept the look of the Euro at 96 but a bit colder with a stronger CAD, there would have been a better chance for some areas to get in on wintry precipitation.  It's a close one on this run but still so far away.

That's the way things are shaping up for now.  I would advise anyone to NOT write this off yet as we still have a few days for changes and if we trend toward the more wetter and icier side of things, then it's something to keep an eye on for sure.  How bad would the ice be if it does trend that way I won't know for sure until we get into the latter part of the weekend but for now, this is looking like a mostly cold rain event with perhaps a bit of sleet and/or a touch of freezing rain to start.  If you have any plans or heading into work for Mon/Tues, there should be no problems on the roads.

Have a good day.

Tuesday, January 11, 2011

Adios Winter Storm....Hola Ice and Cold.

After last week's shenanigans with model watching and weenieism, our storm panned out better, if not MUCH better than some folks expected.  I was surprised myself at some of the total accumulations I were getting, especially for the areas further southeast of Charlotte where upwards of 8 inches were reported and even along the coast, a few folks reported 3+ inches.  I'm very impressed by what this storm was capable of doing and as RUC and SREF kept hinting, it was going to be quite a snowy smack for parts of the SE.  Here was my predicted snow accumulation map:


Back into the areas of northern GA, AL, southern TN, and into AR, thundersnow occurred for those parts, dumping notable amounts of snow due to the increased snowfall rates occurring due to having some instability of the atmosphere and mesoscalic banding associated with strong UVVs (Upward Vertical Velocity or lift).  Some cities received a foot out of this, which already sets them well above average in snowfall for the season.  This was all thanks to the massive slug of moisture associated with our surface Gulf low that rapidly intensified as it carried the rain and snow well north and northeast.  Originally the threat of Gulf Convection due to thunderstorm development earlier that morning was looking rather unfortunate for the Carolinas, which would have disrupted the moisture transport and orientate most of the moisture to spread more west to east instead of southwest to northeast but thankfully the peak of the storms' bowing was reached and the convection relaxed to where it stayed close to the low.  Despite working with a powerfully-dynamic system, the airmass across NC was rather dry and any banding that arrived was immediately ate but was progressively saturating the air as it did so.  Earlier arrival was not expected by some forecasters, and thus snow arrived in Charlotte a little after 3am which briskly accumulated due to the combination of very cold ground temperatures and heavy precipitation which with high snow ratios dumped a quick 4 inches in 2.5 hours for some.  Later that morning, some folks were getting rather concerned about the event ending so quickly with the majority of the moisture staying just to our south, but the RUC, SREF, and WRF argued for afternoon development due to the change in moisture source from the Gulf and instead would be a direct result of the Atlantic Transfer while our surface low (weakened) began to curve toward the Carolina coasts.  Unfortunately, this also brought in a warm nose aloft into the very cold layers, causing the snow to melt and refreeze a bit as the moisture entered back into the cold again for sleet to occur later that afternoon and eventually, freezing rain took over but remained light which reduced the the threat of major damage from ice. Albeit this situation, even a tenth of an inch of ice is enough to cause traveling issues when combined with a few inches of snow on the road and secondary roads became awfully dangerous to drive on especially after some areas received heavy sleet during the evening.  This finally became freezing drizzle for the rest of the night and into the early morning hours.  My advice for today would be to not make any attempt to drive somewhere unless you KNOW you'll get there with no problems.

Overall, this was a terrific storm to monitor and make educated guess of even though it was looking rather bleak when we were 3 or 4 days out but just like our Christmas storm, it came back on some of the modeling withing 24 hours and again getting progressively stronger with each run.  The trend has always (or most of the time) been for moisture to be further north and a system being stronger than progged so far this season, as well as some of the other winters when dealing with a developing southern cyclone.  Unfortunately for the areas further north and northeast of Charlotte, not much snow was attained out of this but there were decent reports of 4 inches in spots so that is good news for those folks.

Speaking of winter, I believe we stand the chance to see one more accumulating winter event this month, whether that be in the form of snow, ice, or both. The pattern supports for such a chance and next mid week might be the time period for the threat. The NAO/AO briefly trends toward the neutral/positive phase but only for the time being around the 16th and beyond into next week (I remain a tad skeptical about it but will not rule out such) with the PNA inching closer and eventually becoming positive. Also if you haven't noticed, the Pacific seems to be awfully busy with a couple of major storm systems out there. Right now there is one that is closing in on the West Coast and that might be the one that affects us next week, but there's another one on its hills that could be it also (the way I see it). We'll have to keep a close eye on this one but temperatures are going to have to cooperate for this one.  Too far north and it will be too warm with rain.  Too far south and no one in northern NC (or all of the state for that matter) will see anything except for southern SC and GA, which I wouldn't mind seeing just so they'll get in on the fun for once.  Go down the middle and you'll end up with an ice storm on our hands and a potentially dangerous one at that with this system expected to be strong at this time with a strong CAD signature.  We'll see what plays out but as of now, I'm not going to focus on it much until Wednesday when the modeling starts to get a bit of a handle on it.  Too much mayhem with this event haha.  There's also indication of a massive intrusion of a very arctic airmass to settle into the US later this week, which would suggests temperatures as low to be in the low teens but I'm thinking we can easily see single digits with enough snowcover hanging around (possibly close to 0 for some)!

Well whatever it is you do, be it sledding, snowball fights (or iceball fights for this matter), or taking a walk around town, just be careful and enjoy the snow that we have here.  Make it a good day everyone!

Thursday, January 6, 2011

No Flurry Show Tonight. Snowy Concept for Next Week on the Increase

What a fantastic set of model runs we had tonight.  Most of the modeling came in with a nice wintry smack for parts of the SE, including areas back into AL and GA.  With that said, here's how the models held up for next week...

GFS- One of the more "impressive-looking" models with the 0z.  It had our low really ramping up in intensity as it slid eastward while temperatures out ahead of it are rather cold between hours 78 and 102.  At 108, that low nears southern GA and spreads its precipitation across GA and SC, with NC getting onto the edge of the shield.  Our 0 850 line drags from Myrtle Beach to southeastern TN while still remaining just south of NC and Upstate SC at 108.  Here's where it gets tantalizing.  From 114-126, that low turns NE a bit and slams much of the SE with heavy QPF totals (indications of over an inch in spots, including the CLT region).  I still fear for the folks from central GA to central SC, as they end up getting a significant ice threat per sounding data.  You are talking about a CRIPPLING ice storm with ice accumulations from .75-around an inch total, especially for central GA.  Much bears watching for them and here as well, where temperatures throughout support snow but we barely hang on to this in a path from GSP to CLT to HKY.  Totals predicted on the BUFKIT suggested at least a foot in the favored areas, including ours.  Beyond 126, the low heads due north and slams the NE as usual.  After this, man does it get downright cold, with temperatures taking a nose-dive on both the highs AND lows.  In fact, after Sunday if the data is correct, we don't break 30 for the rest of next week and we could be dealing with temperatures in the single digits to possibly flirting with 0 as lows!  Not set in stone of course, but prospect is looking high for such.

GGEM- Similar to GFS with, again, heavy snowfall across the SE and thankfully not as much ice for places further south near I-20.  SC actually gets in on heavier snowfall amounts this time around, so that's good news for the folks down there who enjoy such due to having a colder profile.  Going out into the later frames, that ice line nears the CLT region but doesn't quite get in and heads due east from there.  We remain as all snow and are not on pins and needles of an ice threat.    By 108, that frame proves exactly what I mean regarding the heavier snowfall for some areas (http://www.weatheroffice.gc.ca/data/model_forecast/colour_images/00_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012_108.jpg).  Here, we remain as all snow and are not on pins and needles of an ice threat.  Just like GFS, the storm then heads north to hit the NE states (Deja vu anyone?). 

Euro- This model handles the storm much differently than the other two.  For starters, the amount of precipitation is not as significant across NC.  In fact, it is actually from an area around the NC/SC border southward and back into TN is where the winners of the heavier snowfall could take place.  QPF is practically non-existent around the NC/VA border and as you head down here to CLT, it goes up somewhat but I will estimate the QPF total would have to be somewhere between .5-.75 at this time.  Temperatures aloft and at the surface support snow, so we're fine on that part.  One bit of interesting info. that I gathered regarded GSP's sounding data, and it supports all snow with around an inch of QPF.  Places in and near that area may end up getting more than us, and even back into TN the Euro shows some love for them as well, making them winners.  The track of the low is another thing to notice, for it has it a bit further north than 12z, which brings in slightly warmer 850s and also that threat for ice but not as significant as it was on GFS for the same areas mentioned earlier.  In addition with that track, the Euro decides to take it OTS instead of curving it up the coast like the other models did.  This may or may not be a trend, but will keep a close eye on this one in particular.

UKMET- Not much to say about this model, but it appears to have had done better than its 12z run.  Our low is essentially tracking like GFS and GGEM but without trekking along the coast (heads just off the northeastern coast but ends up bombing at 999mb).  It's also similar to the Euro regarding the strength, sitting at 1005mb south of the MS and GA coastal borders and then weakens a bit to 1011mb from hour 96 to 120.  Might as well say that it's similar to the Euro solution but just slightly different overall.  We'll find out more once it gets closer to next week and see what changes from there (if any).

DGEX:  Despite the usual inaccuracy with the DGEX, for once, it may be on to something regarding the 500mb setup at 18z.  It makes as much as sense as what the GFS was doing for the past few runs and has that huge vortex move out of the way and keeping our southern vortex in tact.  Obviously, the moisture looks to be over-performed, but still looks like it has the right idea of where the heaviest could set up.  It ends up bringing over a foot of snow for most areas with a rather robust system that heads into the strong category.  It appears absurd but if one were to take this in reality, the totals would be at least halved and the system being somewhat weaker.  We'll see what the next run shows, which either keeps this or weakens it greatly (leaning more with the second scenario assuming its past behavior).

That about does it for now.  I highly anticipate seeing the 12z runs after tonight's data.  More later.  

Wednesday, January 5, 2011

Round 1: Weds. night- Thurs. Morning. Early Next Week System Still Interesting

Alright.  We are now finally in the period to watch the radar trend with our first system to move in for Wednesday Night-Thursday Morning.  At the moment, current radar shows am ample supply of precipitation breaking out across LA and southern AR with a long stretch going from parts of central and southern MS to west central GA.  As we progress through the day, I expect the bulk of that precipitation to stay to our south.  However, I cannot rule out that another area of precipitation reaches just far enough north to get parts of northern GA, Upstate SC and southern NC for the night time period and early morning.  Take note that this would not be anything significant despite this, so I'm going with flurries or light snow showers at this time.  Dusting would be a safe thing to say as far as accumulations though, but if it's a tad more aggressive, we could see some spots reach an inch, especially for the folks back in northern GA where they could see a couple of inches.

As of this post, I took a look at the RUC at hr. 12 and it has our precipitation continuing to break out in AR, LA, and MS.  Where it goes from there remains the question, but as previously stated, we need to watch the radar trends.  Could get a nice surprise; could not.  It all depends on how our system behaves and where it goes.  I recommend using the water vapor imagery, NOAA radar, and of course the nowcast models for this one.

Regarding our more interesting system next week, there are a few things that I will point out quickly.  If you've seen the 0z GFS, that run had a major change with its solution, going from a GLC (Great Lakes Cutter) to a track heading for Cuba.  At this time, I'm not too concerned with its solution, but I will say that this would be much better to look at than seeing it take our system way north.  If the usual occurs, we will slowly see this trend more northward overtime so I will not throw it out completely but rather I am remaining cautious until I see that trend (if it does).

As for the GGEM, taking verbatim its solution shows quite a smack for parts of the SE signaling a serious threat for wintry precipitation between hours 120-144.  The model cranks out plenty of moisture across MS, AL, and GA and then working across the Carolinas.  Track of the low goes somewhere near Mobile, through southern MS and then turning NE toward the NC/SC coastal border at 1007mb.  Quite impressive.  The Euro has a similar solution to the GGEM, but somewhat weaker and surprising some folks back in ATL with some accumulating snowfall, while up here we are see around .25 QPF or less.  The track is similar but further south once it gets near southern GA, taking our low OTS.  By then at 168hrs., temperatures are really plummeting across much of the CONUS with that brutal arctic air settling in.  Only places like FL or parts of CA and AZ escape from this.      

Here's what I meant regarding GGEM's solution: http://i51.tinypic.com/2u95ndi.gif

So overall, I continue to watch that threat but much more closely than I did a couple of days ago.  Models can and (as we've all seen) WILL change while trying to get a grasp on our developing pattern.  Thanks to our dual blocking that we have going on and indications of the -NAO/-AO tanking, we are looking at a potentially record cold and snowy month (keyword potentially) for this winter.  There are loads of things to monitor as it stands now, and as a few folks have stated, this month promises to keep the majority of us on the edge as we progress through this month.  Winter is far from over at this point, and there's no telling when the next several storm systems will roll in but as always, I will keep you folks up to date the best I can whether it's by the chat I go onto or here.  Remember: "Nothing is certain no matter what your resources are."  That is one of the greatest thoughts any forecaster should have in the back of their mind.

Take care!

Monday, January 3, 2011

So Long Warmth. Deep Detailed Explanation of Potential Arctic Intrusion on the Horizon

As we begin to progress through this week, our 60s are long gone from here.  40s and 50s will return as our highs across the area, but that's not the point I'm making here in terms of our winter.  The bigger story is what could be occurring as we head into mid-January (and I warned folks earlier about how the warm January forecasts are truly in danger).  Now try to bear with me on what I have come across while taking a look at some of the data regarding our Northern Hemisphere pattern.  I can't promise that I explained it all perfectly but I did the best I could to interpret my findings so keep that in mind.  

NOTE: This is what I gathered from the previous runs of some of the modeling (mainly Euro), so the new runs DO NOT apply to this...

Alright.  Going back to late December when our Christmas Storm was forming out west, our pattern featured the Greenland Block sitting up north with our East Pacific trough in place and an upper level low sitting off the East Coast.  Meanwhile, a piece of energy entering southwestern California (developing system) was ready to make its way across the Southern U.S.  Now we all know that eventually, that system ended up bringing us our snow from late Christmas Eve and early Christmas Day thanks to our two streams phasing at just the right time to help amplify that storm.  As that lifted out on the 26th, the pattern shifted to where troughing was now taking place along the West Coast, ridging through West-Central U.S. and into Western Canada, and then troughing over the Eastern U.S.  Are you with me so far (at least I hope so haha)?

Moving along to yesterday (per 0z Euro data), the pattern shifts to where ridging takes place in Alaska with a trough diving through Central U.S.  From there, I begin to notice something about our Greenland Blocking that caught my interest greatly, and that was the sign of it beginning to strengthen...powerfully.  From hours 72-120, that block becomes much greater than it was.  The polar vortex has no choice but to head southward after our block moves westward and soon ends up being displaced to where the Great Lakes are get hammered by this nasty intrusion of cold air.  Around this time, a disturbance that showed up on the 72hr. ends up as a potential coastal storm for the upcoming weekend (more likely for the northeastern states), but those details are still being worked out.  The block at this point has become even more powerful (and that word is starting to sound like an understatement at this point).

Now as for the 0z Euro Ensembles, the energy is a bit more powerful in this case.  On Jan. 6, our southern feature at 1007mb is off the NC coast from Cape Hatteras that has swung through the SE.  At this point, if anything did happen with it, we would see a bit of snow out this but nothing to get excited about.  Also to our north, an upper air feature settles in place over the Great Lakes associated with the PV.  That eventually combines with that southern feature and ends up becoming a major storm system for the NE with that arctic air beginning to intrude over the NE and MA.

Heading toward hr. 168 on the Euro (Jan. 9th), the PV gets displaced WAY south by a few hundred miles or so.  The reason for that is because the model now shows that block as a VERY MASSIVE (from NE Canada all the way to Yukon)!  With that vortex being this far south, any southern system just gets suppressed quite a bit.  That low is pushed into southern MS and AL and by Day 10, it ends up trying to traverse along the East Coast but is still SE of Hatteras.  When it leaves, that arctic air grasps the SE and we are looking at a nasty outbreak forming.  Speaking of this setup, the CMC at Day 7 (hr. 174) wants to change this and cause an over-running pattern instead, which would have the moisture flow from TX toward the Carolinas and VA while the arctic air is pressing southward.  Granted this isn't a major system being depicted here, but I figured I mention it for the sake of it.

Now as for GFS, I'm not too concerned about what it showed mainly because of what it has done with our PV.  The model takes this and places the vortex in the NE around Boston!  I wholeheartedly doubt this will verify due to it handling the feature way too far south.  In this case, our shortwave would get utterly destroyed by this and you have absolutely nothing to work with.  Interesting to note, this would bring some -15 850s to parts of the Eastern U.S. which is very brutal for some folks.

At 500mb on the 12z Euro during hr. 216, it models the PV back in the Dakotas thanks to it having the Gulf low present with blocking going from Eastern Canada to the Northern slopes of Alaska.  Euro ensembles has a disturbance taking shape in the Plains with a jet stream flow from Japan all the way across the southeastern states with that Alaskan Ridge still there.  This tells me that a stormy pattern is coming up later on, which makes things interesting down the road.  Euro at Day 10 at hr. 240 has the vortex sitting over Pittsburgh of all  places with this dip taking place across the Central U.S.  That dip represents something known as the Siberian Express.  With the ridge along the West Coast and the block settling over Eastern Canada, that arctic air gets spilled southward and toward the Eastern U.S.  Consequently, this causes VERY COLD air to take over most of the U.S., even down across parts of the Deep South such as the Panhandle of Texas or Arkansas!!  Back across our region per 12z OP, there are -14 to -16 850s over most of NC with -20 850s in the Apps!  Unbelievable of how powerful this arctic air is.  Then finally on the 12z Euro Ens., they show those very cold anomalies pushing eastward into the Eastern U.S.

Having all that said, we could be easily averaging this month as below average if that arctic intrusion comes to play.  Course, this will limit our precipitation chances but we'll see.  This was just something I wanted to summarize from last night's runs but didn't get a chance to type this due to my illness throughout yesterday (had a massive headache and an upset stomach).  Speaking of precipitation, while this weekend's not looking impressive, next weekend seems quite promising and could be a significant hit if this pattern adjusts for such, but I'll explain that later.  For now, take care everyone.