Jan 15-16 Winter Storm

[Brick Tamland]

4 minutes ago, NorthHillsWx said:

Trend seems up be a more amped low and with that more precip type issues. Such is life in the south. I really like everywhere along the 85 corridor and would feel very comfortable at this point. It digs far enough south to put even Atlanta in a fantastic spot. Issue is definitely when it begins to make the northward push and how Far East it gets before then. Seeing an extremely amped sub 995 low crossing SE NC is not going to be good for Raleigh proper to stay all snow. Those are minute details with huge implications at this point. A major storm seems likely in the south and we have days of model runs to sort those details out. The trend certainly seems though that there is more likely to be a piedmont-east screw zone than we were thinking at this time yesterday 

I wonder if the Triangle is going to have to get used to seeing the warm nose more and more. It certainly seems to come further west and north than it used to. Greg Fishel said something with the last snow storm that the air coming off the ocean makes it warmer in the Triangle and harder to get snow than west of the Triangle. I think the more we see the oceans warming the more we'll see this happening and the warm nose continue to increase further west and north when we have a winter storm threat. 

[Prismshine Productions]

CAE has joined the party:

.LONG TERM /SATURDAY THROUGH TUESDAY/...

-- Changed Discussion --

...Potentially Impactful Winter Weather on tap Saturday through Sunday Night... ======================= SYNOPTIC OVERVIEW ======================= Synoptic flow through this period can be classified as meridional, as the shortwave trough on Thursday digs through the region and ushers in broad northwesterly flow across the eastern CONUS. As this 500 hPa trough deepens off the US east coast, a strong surface high pressure system will begin moving from the prairies of Canada towards southeastern Canada and the northeastern US. This will begin to ridge into the Mid-Atlantic and Carolinas by Friday, and even more so on Saturday. Models are in very good agreement overall with this initial progression of features, with Ensemble and Deterministic models agree on this progression. Meanwhile, model guidance has come into fairly good agreement on the location and strength of another mid/upper level shortwave. This positively tilted trough is forecast to dig into the southern MS Valley by Saturday morning, and will push towards our region Saturday night and into Sunday. Ensemble means and deterministic models are all showing this in some similar form, with a surface low of varying strength developing across the Gulf Coast states and traversing from there and into the southern GA/northern FL. Ahead of this, the strong surface wedging looks to be in place across the region, with cool air already locked into place. From a pattern recognition standpoint, this is a favorable synoptic set up for wintry weather around the region. Precipitation is expected to increase in earnest on Saturday night ahead of this as isentropic lift increases across the area atop the surface wedging. Guidance is mixed in terms of p-type, and it is a bit early to get into these details. However, the pattern would suggest rain, snow, sleet, and freezing rain all being possible during this event. Behind this system, high pressure and dry air push back into the region to start the next work week. ======================= MODEL DISCUSSION ======================= We have increasing concern that a wintry mix of rain, sleet, freezing rain, and snow may impact the region this weekend. Model guidance is in somewhat remarkable agreement with the overall pattern and even some details of the pattern. The ECMWF begun this trend yesterday, and since, the GFS and Canadian have pushed towards that, along with their ensembles. Ensemble means are impressive, showing trends towards a deeper and more amplified shortwave over the MS Delta region as it pushes a surface low towards us. The ECM is the weakest with the 500 hPa shortwave, keeping it as a fairly progressive, open wave. The GFS and Canadian have quickly trended towards a closed 500 hPa low tracking near the region on Saturday night. The ECM would suggest more of a frozen precip type, but the trend in the 00z GFS/Can & 12z GFS is concerning, pushing strong warm air advection atop a cold layer & resulting in some ice. Model trends and agreement, both in the deterministic and ensembles, are certainly concerning and bear watching over the coming days. Models are fairly uniform in showing the precip generally starting after midnight on Sunday and lasting through Sunday evening. Leaning towards the stronger solutions given the trend towards them within the ensemble guidance. Model guidance did a similar thing (though withing 48h of the event itself) on Jan 2nd-3rd, when they quickly picked up on a deepening and closed low. One other trend to note in the 12z guidance is that the surface high ahead of this is slightly further south and slightly more intense across our region immediately ahead of the surface low. ======================= FORECASTER CONFIDENCE ======================= Forecaster confidence is increasing in some kind of winter weather event impacting the Carolinas on Saturday night and Sunday. So that answers two of the four big questions ("Where?" and "When?"). The "What?" and "How Much?" is still TBD at this point. A couple of things to note: - This could still trend away from a winter weather event. We are several days out from this event, and there is a lot of uncertainty involved in a forecast where precipitation types look to be an issue. - While forecaster confidence is increasing in something happening this weekend, confidence in p=type, amounts, and impacts is not high at this time. Depending on "What?" falls and "How Much?" actually occurs will determine overall impacts of this event. - Guidance is notoriously poor at predicting when and how long a wedge situation will set up across our region. They are usually too quick to scour it out, and usually push us out of a wedge too early. This is important because this set up will be driving any wintry precip that occurs across the area. Given all that I have outlined, I am most confident that areas along and north of I-20 are under the greatest threat for a wintry mix of precipitation this weekend. This doesn`t mean future model trends won`t push in a different direction, but given the weight of the ensemble & deterministic guidance at this point, that is the area of greatest confidence. I want to reiterate - this is a forecast with high variance and several potential outcomes at this point. Stay abreast of latest forecasts over the coming days as details come into clearer view about potential wintry weather across the Midlands and CSRA.

-- End Changed Discussion --



Sent from my SM-S115DL using Tapatalk

[calculus1]

37 minutes ago, buckeyefan1 said:

HKY

Thanks for posting these meteograms, Buckeye.  I just can't fathom all the pretty colors on these charts for Hickory -- there are so many pinks and purples, on both the ECMWF and the GFS ensembles.  We aren't supposed to get nice things.  I love the bonus bump in snow on the GFS too.  As if 12 inches with the first one isn't enough, let's tack on an additional 8 inches a week later.  Yessir!

 

13 minutes ago, buckeyefan1 said:

GSP 

The track of the low will determine how strong
of a warm nose might develop from the south, which would greatly
affect the precip-type distribution. The QPF blend right now is
especially modest, and the conservative approach is preferable
for a system that is still out on Day 4/5. In spite of the trend,
readers are cautioned to manage their expectations...at least for
the time being. Stay tuned.

My favorite part of the GSP AFD is the bolded here.  We are cautioned to manage our expectations.  Yeah, we're not too good at doing that on weather boards. 

[StantonParkHoya]

2 minutes ago, Brick Tamland said:

I wonder if the Triangle is going to have to get used to seeing the warm nose more and more. It certainly seems to come further west and north than it used to. Greg Fishel said something with the last snow storm that the air coming off the ocean makes it warmer in the Triangle and harder to get snow than west of the Triangle. I think the more we see the oceans warming the more we'll see this happening and the warm nose continue to increase further west and north when we have a winter storm threat. 

Brick, you could put this synoptic set up in 1822 and I guarantee there'd be a big warm nose.

[flotownsc]

Can someone post KFLO’S gram’s?


.

[buckeyefan1]

1 minute ago, calculus1 said:

Thanks for posting these meteograms, Buckeye.  I just can't fathom all the pretty colors on these charts for Hickory -- there are so many pinks and purples, on both the ECMWF and the GFS ensembles.  We aren't supposed to get nice things.  I love the bonus bump in snow on the GFS too.  As if 12 inches with the first one isn't enough, let's tack on an additional 8 inches a week later.  Yessir!

 

My favorite part of the GSP AFD is the bolded here.  We are cautioned to manage our expectations.  Yeah, we're not too good at doing that on weather boards. 

You are most welcome! I'm trying not to leave anyone out 

[Prismshine Productions]

Just want to point out that hr78 of the 18z NAM (hr84 of 12z) trended a few degrees cooler...

Sent from my SM-S115DL using Tapatalk

[Buddy1987]

Someone can correct me if im wrong but 18z Icon looks west with vort energy

Edit: Ah ok.. much more strung out with the energy in the Plains. Not closed at 500 not even close. 

[rduwx]

17 minutes ago, Brick Tamland said:

I wonder if the Triangle is going to have to get used to seeing the warm nose more and more. It certainly seems to come further west and north than it used to. Greg Fishel said something with the last snow storm that the air coming off the ocean makes it warmer in the Triangle and harder to get snow than west of the Triangle. I think the more we see the oceans warming the more we'll see this happening and the warm nose continue to increase further west and north when we have a winter storm threat. 

I know over the past 20 years of tracking storms for this area that the warm nose is always under modeled.  I'm not sure the reason but there have been many times models showed all snow and I had mixing issues.  Just the area we live in.  I'm looking forward to a possible storm this weekend but I believe it's always best to count on mixing issues for the RDU area.  Therefore you're not surprised when it happens.  Not necessarily directed at you Brick.  The good news is the mixing makes for some good sledding weather.  Yes, 52 years young and still go sledding with the kids...LOL!

[eyewall]

1 minute ago, rduwx said:

I know over the past 20 years of tracking storms for this area that the warm nose is always under modeled.  I'm not sure the reason but there have been many times models showed all snow and I had mixing issues.  Just the area we live in.  I'm looking forward to a possible storm this weekend but I believe it's always best to count on mixing issues for the RDU area.  Therefore you're not surprised when it happens.  Not necessarily direct at you Brick.  The good news is the mixing makes for some good sledding weather.  Yes, 52 years young and still go sledding with the kids...LOL!

As of now I am inclined to suggest this will be more of a mix event than a snow event in central NC, especially with it moving toward the Miller B side of things.

[snowmaker13]

3 minutes ago, Buddy1987 said:

Someone can correct me if im wrong but 18z Icon looks west with vort energy

Edit: Ah ok.. much more strung out with the energy in the Plains. Not closed at 500 not even close. 

That's what you want to see at this time. More amped means a app or possibly lakes cutter. 

[burgertime]

Last post of the night for me. Icon is snowier for NC. See you for the 00z runs! 

[Disc]

I will say this: I have never made a forecast using the ICON model. Entertainment at best.

[Buddy1987]

Just now, Disc said:

I will say this: I have never made a forecast using the ICON model. Entertainment at best.

What a weird ass evolution based on how it got there at 108 wow LOL

[CaryWx]

Thanks Burger

[Beach Snow]

agree from what i have read and here but a much more surpressed track than 12z.

[Wow]

ICON less dig but weaker... SLP still Miller B but not too strong to wipe out the mid level cold. 

[NorthHillsWx]

6 minutes ago, eyewall said:

As of now I am inclined to suggest this will be more of a mix event than a snow event in central NC, especially with it moving toward the Miller B side of things.

This ^^^.  Will try to keep pessimism at a minimum knowing someone in our sub forum is going to have a big storm but I do not like the trends for the Raleigh area proper 

[Tigerchick224]

My favorite part of the GSP AFD is the bolded here.  We are cautioned to manage our expectations.  Yeah, we're not too good at doing that on weather boards. 

Laughs in Weather Weenie!


.

[wncsnow]

This system is showing up a lot in CIPS analogs as well

[beanskip]

11 minutes ago, rduwx said:

I know over the past 20 years of tracking storms for this area that the warm nose is always under modeled.  I'm not sure the reason but there have been many times models showed all snow and I had mixing issues.  Just the area we live in.  I'm looking forward to a possible storm this weekend but I believe it's always best to count on mixing issues for the RDU area.  Therefore you're not surprised when it happens.  Not necessarily directed at you Brick.  The good news is the mixing makes for some good sledding weather.  Yes, 52 years young and still go sledding with the kids...LOL!

Yeah this is SOOO true. Now that I'm just an observer from afar, it helps check my "excitement bias" -- the two main biases are underestimating the "nose" and ignoring model issues with boundary layer temps. Can't tell you how many times I've been a sucker for those who say "meh, heavy precip rates will overcome those +3 BL temps" and then cursed my naivete as I watch it rain. 

Having said that -- good luck, everyone, from Tallahassee. I'll be rooting hard for the BIG DOG!

[rduwx]

Even though I don't have much confidence in the ICON, for those in central to eastern part of NC, this is the type of track and strength we'd like to see.  Haven't seen snow totals but would expect higher totals for the RDU area.  I do believe there would still be some mixing but not near as much.

[SnowDawg]

CMC finally came back to life and finished its run.

[HKY_WX]

2 hours ago, ILMRoss said:

In my opinion, a clear villain emerged from this model suite: This shortwave: 

This shortwave comes in on just about every global and slingshots our ULL to the northeast, which drives it up the coast. In previous runs, this wasn't an issue because our less amped, quicker system was able to outrun this shortwave. However now that everything's slower, the circled shortwave is exerting some influence. If this shortwave wasn't here, I think the ULL would continue to take a more lateral movement through the SE, putting more southern solutions at play. 

Agree with this. That shortwave will likely decide the fate of the RN/SN line and where it sets up. The orientation will be more SW to NE with more phasing as opposed to a March 1980 murphy to manteo I40 type storm.

[Grayman]

Early congrats to the usual winners. north western NC and S VA. I’m down here in Rockingham NC with fingers crossed but we know who wins 95% of these times in NC. 

[wxduncan]

I think Hickory NC is a good spot to be in right now. I just hope NW trends don't start because we get burned to many times here in the Lee Side. But the best to everyone I hope it's a good 4 inches at least for the whole state.

[85snowline]

1 hour ago, PantherJustin said:

This a true statement I grew up by Afton Village. Everyone even up by Rowan County/Iredell County line would smash. Luckily I’m over in Mooresville Now. South Concord like Downtown- Never gonna fare well in a CAD setup 

Afton Village is awesome.. A bit congested these days.. but.... winter wx in Cabarrus County literally makes me crazy. I'm basically on the border w/ Harrisburg between 29 and 49. It's all about now-casting in these parts.

[olafminesaw]

Does the Northward trend of the trough moving through on Thursday have anything to do with the amplification trend?

[BooneWX]

4 minutes ago, wxduncan said:

I think Hickory NC is a good spot to be in right now. I just hope NW trends don't start because we get burned to many times here in the Lee Side. But the best to everyone I hope it's a good 4 inches at least for the whole state.

We’ve earned one. We get shafted every single storm that doesn’t come from this direction. 

[WinstonSalemArlington]

35 minutes ago, Disc said:

I will say this: I have never made a forecast using the ICON model. Entertainment at best.

For some reasons, tv nets are trending toward favoring ICON.