November 2013 pattern and discussion

[Huffwx]

Agree and disagree.

 

Most classic Miller A's have a small ip/zr band. However, there are MANY exceptions. 

 

Miller B as a ZR/IP maker is an option, but not a "normal" outcome. 

 

 

Grit is right.... not seeing freezing rain with this one. Freezing rain comes from Miller B's not Miller A's. It will be either rain or snow. Soundings look suspect. I can't see 925's colder than 850's in that pattern.

[dsaur]

Lol climo? I guess it's normal to see 3-5 day snow/freezing rain/sleet events in Texas in November. Wintry precipitation is just as rare in Dallas as in NC. I guess climo isn't going to allow wintry precipitation there even though the models are trending colder for that area.

I'd say this event you are describing is rather common out there.  At least since I've been watching weather.  Texas always gets the good sleet/sn storms, and for days, and by the time it gets here, it's sunny and warm, lol.  It's climo, just like the track they like in Carolina doesn't help me at all because they are closer to the cold cad high, and I'm closer to the warm, warm storm.  It's rarely good for everybody at the same time, but those Texas folks luck out more than is fair.  Of course they get up to 120 in the summer, so they get cut some winter slack. Heck they get snow, and ice and sleet down, way down in Texas, down near the equator where you are, but when it tracks across, you get tornado warnings instead of snow warnings...does that seem fair to you?  They just lucked out by location relative to the land of ice and snow, and when a blizzard high blasts down from the north pole, it winds up in the gulf south of Texas, and not over WayGone.  And what's worse is when the blast does head for WayGone, it's a sunny 10 degrees, but when it's Galveston, it's 3 days of sleet and zrain, lol. 

[buckeyefan1]

Just passing along info from bufkit etc.  Not experienced enough with the dynamics and all that.

GFS 18z does show ZR

 

131127/1200Z 138 03010KT 37.1F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.021 0:1| 0.0|| 0.00|| 0.00|| 0.02 0| 0|100

131127/1500Z 141 04013KT 37.7F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.024 0:1| 0.0|| 0.00|| 0.00|| 0.05 0| 0|100

131127/1800Z 144 03014KT 37.3F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.038 0:1| 0.0|| 0.00|| 0.00|| 0.08 0| 0|100

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

131127/2100Z 147 03016KT 36.2F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.055 0:1| 0.0|| 0.00|| 0.00|| 0.14 0| 0|100

131128/0000Z 150 03018KT 35.5F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.550 0:1| 0.0|| 0.00|| 0.00|| 0.69 0| 0|100

131128/0300Z 153 03021KT 34.8F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.225 0:1| 0.0|| 0.00|| 0.00|| 0.91 0| 0|100

131128/0600Z 156 03020KT 33.2F RAIN 0:1| 0.0|| 0.00|| 0.00|| 0.086 0:1| 0.0|| 0.00|| 0.00|| 1.00 0| 0|100

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

131128/0900Z 159 02020KT 31.7F FZRA 0:1| 0.0|| 0.00|| 0.36|| 0.347 0:1| 0.0|| 0.00|| 0.36|| 1.35 0| 0|100

131128/1200Z 162 02017KT 30.8F FZRA 0:1| 0.0|| 0.00|| 0.25|| 0.238 0:1| 0.0|| 0.00|| 0.61|| 1.58 0| 0|100

131128/1500Z 165 04014KT 32.3F RASN 0:1| 0.0|| 0.00|| 0.00|| 0.083 0:1| 0.0|| 0.00|| 0.61|| 1.67 88| 0| 12

 

EDIT.....

It looks like I get to enjoy 33 and rain   

 

131128/1200Z 162 03018KT 33.9F RAIN 

[superjames1992]

Lol climo? I guess it's normal to see 3-5 day snow/freezing rain/sleet events in Texas in November. Wintry precipitation is just as rare in Dallas as in NC. I guess climo isn't going to allow wintry precipitation there even though the models are trending colder for that area.

 

Actually, (according to Wikipedia, anyways) Dallas averages 1.5" snow/year while Raleigh averages ~6.5", Charlotte ~4.5", and Greensboro ~8.5".  Dallas averages roughly the same amount of snow as Atlanta, though.

[superjames1992]

Eh, I've seen ZR from Miller As before.  12/19/09 had quite a bit of IP, then ZR and freezing drizzle at the tail end of it.  I think 1/31/10 might have ended with some ZR and IP, too.  It's certainly not typical, but it can happen.

[NCCatawba]

from what you just showed I'd say NOT RELIABLE at all....

 

Yea EURO probably wrong...actually has Mount Airy at 5" which is close to half of your seasonal snowfall I think? Has around 3.5" in Hickory. 

 

I think the free twisterdata snowfall map actually does pretty well. It again shows a max east and west of you and me. Shows a nada punching through the extreme southern foothills...usually this will become more pronounced closer to the event and eventually shadow all accumulations over the foothills. This usually out does the EURO every single time.

[dsaur]

Agree and disagree.

 

Most classic Miller A's have a small ip/zr band. However, there are MANY exceptions. 

 

Miller B as a ZR/IP maker is an option, but not a "normal" outcome. 

When these Fla tracking gulf storms get into cold air, there is usually a dividing line down Atlanta way between rain, snow, and zrain in Macon and LaGrange, sleet/sn/zrain here, sleet and snow Atlanta north.  See that here a lot.  It's unusual for it to be all snow, all storm, Macon north as opposed to the mix.  We dance such a tight line down here between the Waa and the Caa. It's why a Fla. track is always what I want, unless the cold air is deep and well reinforced.  Such a tight line between cold rain and snow, with the mix in between, and it will wobble up and down state if it's a long storm.  Usually for us a weaker storm is best.  In 73 I saw over 3 inches of ice from a slowing moving gom low that was strong.  After that I like 'em strong for the cold rain, and moderate to weak for the fun stuff.  Don't much care if I never see zrain again, but it comes with living in Ga.  We see a lot of zrain, while north of Gainesville it's all snow.

[GaWx]

Fwiw, Euro weeklies for SE US issued Thursday, 11/21/13:

 

Week 1 (11/25-12/1): very cold with 8-10F below normal and wet (~2" qpf)! +AO/+NAO

 

Week 2 (12/2-12/8): cool with 1-3 F below normal and fairly wet (~1-1.5" of qpf) +AO/+NAO

 

Week 3 (12/9-12/15): near norm temp.'s with slightly drier than normal (~0.50-0.75" of qpf) neutral AO/NAO

 

Week 4 (12/16-12/22): near norm temp.'s with near to slightly wetter than normal (~0.75-1.25") neutral AO and slight -NAO

 

Alaskan ridging (higher than normal 500 mb heights) is very strong week 1 but it weakens thereafter and becomes mainly troughing weeks 3-4

[Shawn]

 

EDIT.....

It looks like I get to enjoy 33 and rain  

 

131128/1200Z 162 03018KT 33.9F RAIN 

 

There is still a small chance to get a bit.  Long ways out.. but the way the CAD dives in, pretty quick here.

[FLweather]

Not seeing any way the 18z GFS is freezing rain...it's Miller A sfc coastal low with 500mb vort max tracking to our south...rain or snow all the way

So true. While it can happen its very rare. This is the ideal setup for snow anytime in the winter. That I think will be the case here.... either cold rain or snow.

 

Honestly I think the models are having a tough time on the pattern pulling out the cold air too fast on the return flow from the HP. 

[Brick Tamland]

I just checked the Euro monthly run that came out today (apparently it's released sooner than I realized).  Starts off with cold shots coming in one after another, not staying long, but they are frequent.  By about Dec 11 it turns mild and stays that way.  This seems to go along with Don Sutherland's current line of thinking.

 

Edit:  Moisture wise, looks like a pretty juicy system around the 6th followed by another one around the 8th or 9th, then dry until the end of the run.

 

It is fun having something like this already in November to keep an eye on. I hope this continues into the winter and we have a lot of chances for wintry weather. However, this doesn't make me as excited. Maybe we can get something at the first half of December, though, and things can change again for the better for January.

[WeatherNC]

Just a few minor details to work out between the 12z GFS and Euro at 144hrs 

 

GFS

 

EC

 

As you can see from the H5 graphics above, the GFS is a pure southern stream with little to no involvement of the polar jet.  The Euro on the other hand hooks them up late, as indicated by ~200m height differences over the OH Valley.  Either case is not conducive for a widespread SN even for the interior SE or even lower portions of the MA.  One would want to see a more pronounced PNA than what either model shows, with a rogue parcel riding down and amplifying the sw/cutoff ivo the lower MS valley.  The differences illustrated above though are going to have an impact on sensible weather, if the Euro is has a better handle and there is interaction, the SLP will quickly jet to the NE, with Nor-Easter potential into the N MA and NE.  Fo us to the south, this could be a more interior track with the surface low riding slightly inland.  The GFS, with little to no interaction, crawls the low along the SE coast, excellent RN event, and while the Miller A solution supports narrow transition zones, there has been exceptions (more on that in closing).

 

Off to the 200mb maps, both models show a strong signal for EC cyclogensis (not quite bombo) when looking at the upper level jet.  Solid vacuum cleaner (Euro more so) in place to the north, no wonder they have been honking at the coastal for days.  Southern energy is coming in with pretty good timing, this is one of the reasons it amplifies rather than dampens out.  Bother graphics again from 12z, valid 144hrs.

 

GFS

 

EC

 

Neither models shows a SN signal imo outside of the mountains, and maybe up into the VA Blue Ridge vs NC.  With verification closer to the Euro there is lower heights being drawn done, but the interaction takes place way too late for the foothills and W TN, if you were to speed the that up the SLP would cut even further inland with the absence of a pronounced PNA.  Unsure what to make of the GFS, where is it getting the shallow surface cold pool from that has a sig ZR event in W NC?  Soundings and thickness plots are the best tool for determining p-type.  Sure you can argue a M-A vs M-B, RN/SN vs mixed bag with large and sometimes irregular transitions, but there are exceptions.  Even with TREND on the nonogram, you will see instances where RN verified in what should have been an otherwise sn event.  Soundings don't lie, models do (especially 6 days out) but the signal is certainly there for amplification of a surface wave coming out of the gulf.  

[Stovepipe]

It is fun having something like this already in November to keep an eye on. I hope this continues into the winter and we have a lot of chances for wintry weather. However, this doesn't make me as excited. Maybe we can get something at the first half of December, though, and things can change again for the better for January.

 

It's November.  Pull yourself together man!

 

[FallsLake]

So true. While it can happen its very rare. This is the ideal setup for snow anytime in the winter. That I think will be the case here.... either cold rain or snow.

 

Honestly I think the models are having a tough time on the pattern pulling out the cold air too fast on the return flow from the HP.

Exactly. This is some very cold/dry air coming in this weekend. Read somewhere maybe coldest since 1938(??). The latest 18z GFS still shows dew points near zero(Raleigh area) for the Monday Tuesday time, but now keeps it (colder)near freezing throughout the event with the very cold/dry air staying very close up in Virginia. Then as the system starts to move out all the cold/dry air up in Virginia comes crashing back in. We need to keep an eye on this initial air mass; I think it is the key to if anybody gets any wintery precip.

[John1122]

Keep in mind that this is late November, just a few days from climatological winter beginning. On today's MRX weather facts page it's speaking of the 16.2 inches of snow that fell in 24 hours in the Tri-Cities in 1952. 2-4 inch snows aren't uncommon at all in the last week of November and first week of December in East Tennessee/Western NC areas.

[downeastnc]

Dec 3 2000 was epic for us, and I dont see why something like that couldnt happen a week earlier given the right setup, so while I normally dont expect significant snows before late Dec into Jan/Feb they are possible.

 

The forecasted high Sunday of 41 woud tie the min max record for that date at PGV be nice to set a new all time record low max for the date.....

[griteater]

Looking at the 18z GFS Ensemble members on ewall, I see 7 that more or less keep the northern and southern streams separate, and 5 that show northern stream interaction, pulling the sfc low up the NE coast.

[metalicwx366]

This will be as cold a November as I can remember, we are definitely going to finish a negative departure, the question is how much.

Last November was much much colder.

[toxictwister00]

Last November was much much colder.

Maybe where you are, but November 2012 was definitely warmer than this November currently is here. Thanksgiving week might just be enough to end the month at the very least slightly below average.

[CAD_Wedge_NC]

Agree and disagree.

 

Most classic Miller A's have a small ip/zr band. However, there are MANY exceptions. 

 

Miller B as a ZR/IP maker is an option, but not a "normal" outcome. 

 

Just for the record, this is November not January.... Freezing rain from a miller A storm in November in the Southeast US is very rare. Look at Nov 19, 2000. This time of year, the low levels will not get cold enough without the mid levels being cold enough for snow. Most likely the transition line will be snow and sleet to plain rain over a short distance. That is unless the low-level air is super cold....and it will not be with this storm.

[CAD_Wedge_NC]

Last November was much much colder.

I am afraid he is right....Last November finished up with a departure of -2.8 degrees and this year we are sitting at -1.3 degrees to date. However, next week looks to bring that number down somewhat.

[metalicwx366]

Maybe where you are, but November 2012 was definitely warmer than this November currently is here. Thanksgiving week might just be enough to end the month at the very least slightly below average.

Come on lets be realistic here.

Atlanta temperature graph last year. -3 departure.

This year. Currently 0 degree departure.

[Cold Rain]

Just a few minor details to work out between the 12z GFS and Euro at 144hrs

As you can see from the H5 graphics above, the GFS is a pure southern stream with little to no involvement of the polar jet. The Euro on the other hand hooks them up late, as indicated by ~200m height differences over the OH Valley. Either case is not conducive for a widespread SN even for the interior SE or even lower portions of the MA. One would want to see a more pronounced PNA than what either model shows, with a rogue parcel riding down and amplifying the sw/cutoff ivo the lower MS valley. The differences illustrated above though are going to have an impact on sensible weather, if the Euro is has a better handle and there is interaction, the SLP will quickly jet to the NE, with Nor-Easter potential into the N MA and NE. Fo us to the south, this could be a more interior track with the surface low riding slightly inland. The GFS, with little to no interaction, crawls the low along the SE coast, excellent RN event, and while the Miller A solution supports narrow transition zones, there has been exceptions (more on that in closing).

Off to the 200mb maps, both models show a strong signal for EC cyclogensis (not quite bombo) when looking at the upper level jet. Solid vacuum cleaner (Euro more so) in place to the north, no wonder they have been honking at the coastal for days. Southern energy is coming in with pretty good timing, this is one of the reasons it amplifies rather than dampens out. Bother graphics again from 12z, valid 144hrs.

Neither models shows a SN signal imo outside of the mountains, and maybe up into the VA Blue Ridge vs NC. With verification closer to the Euro there is lower heights being drawn done, but the interaction takes place way too late for the foothills and W TN, if you were to speed the that up the SLP would cut even further inland with the absence of a pronounced PNA. Unsure what to make of the GFS, where is it getting the shallow surface cold pool from that has a sig ZR event in W NC? Soundings and thickness plots are the best tool for determining p-type. Sure you can argue a M-A vs M-B, RN/SN vs mixed bag with large and sometimes irregular transitions, but there are exceptions. Even with TREND on the nonogram, you will see instances where RN verified in what should have been an otherwise sn event. Soundings don't lie, models do (especially 6 days out) but the signal is certainly there for amplification of a surface wave coming out of the gulf.

This is an excellent, excellent post, worth reading a few times. I wanted to reply to it to acknowledge the effort and the accuracy of the information given.

Regarding ZR, it's hard for me to see a scenario, given the current set-up, where anyone would see any meaningful ZR, outside of a brief bit at onset. This is likely going to be mostly rain, with snow being the predominant non-frozen type, if there is any. There could be, but there's still more work to be done with the players on the field.

Anyway, good post, sir.

[griteater]

It looks like there is going to be more northern stream involvement this run

[Reb]

yep low looks farther north at 114

[FLweather]

It looks like there is going to be more northern stream involvement this run

 

Yeah looks that way... stronger push of cold air coming down out of the plains compare to 12z.

[NCCatawba]

[griteater]

Ptype maps have rain to snow in NC Mtns, TN, far north AL/GA as the 500mb low sweeps through.  Looks like your run of the mill noreaster.

[NCCatawba]

[Reb]

trending toward euro?