Wintry Saturday 12/17 light ice threat

[WeatherLC]

Hopefully I don't jinx it but I thought I would start a new thread for the weekend storm threat. Will be interesting to see if the 0z runs keep the trend going.

 

[Snowflowxxl]

oh snap! first southernwx storm thread! Lets hope its good!

 

[Storm5]

oh snap! first southernwx storm thread! Lets hope its good!

if it's not good for the CAD areas and thread fails Gainesville will be banned from ever starting another thread lol

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[CummingWx]

Hello. My first post here. I keep hearing there could be bad news for us (the precip is delayed until it's too warm and the high is transitory so it doesn't keep supplying us with cold dry air). Regardless, CAD is almost always underestimated so I'm guessing before it's all said and done someone in NE GA will have some ice problems saturday morning. Just a big question how far south and west it will be and if it gets bad or not.

 

[WeatherLC]

[quote author=SnowFlowXXL link=topic=46.msg1621#msg1621 date=1481588611]
oh snap! first southernwx storm thread! Lets hope its good!

if it's not good for the CAD areas and thread fails Gainesville will be banned from ever starting another thread lol

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[/quote]
Haha I'll take that chance. I'll be interested to see what the name and 4knam show as we get closer. The 4knam has been fairly accurate with past storms if I recall correctly.

 

[WeatherLC]

To me this looks like a hybrid damming situation at best. The GFS is only showing about 6 hours of ZR duration before the high moves off shore. Also the precip does not look to be all that heavy, so I have to wonder if we would be able to truely tap the wetbulb potential? Please correct me if I am wrong, I'm learning. 

 

[Tarheel1]

To me this looks like a hybrid damming situation at best. The GFS is only showing about 6 hours of ZR duration before the high moves off shore. Also the precip does not look to be all that heavy, so I have to wonder if we would be able to truely tap the wetbulb potential? Please correct me if I am wrong, I'm learning. 

Models 9 out of 10 times under estimate the strength and duration of wedges in the CAD areas, early start time can lock in even an in-situ CAD. I mean a difference of 1-2 degrees, can have huge ramifications!

 

[Shawn]

To me this looks like a hybrid damming situation at best. The GFS is only showing about 6 hours of ZR duration before the high moves off shore. Also the precip does not look to be all that heavy, so I have to wonder if we would be able to truely tap the wetbulb potential? Please correct me if I am wrong, I'm learning. 

Yeah, CAD situations usually hang on longer than forecast.  I don't believe the models ever really handle the true "dryness" of the air in these situations either for the wetbulb process.

If you get too much rain too fast (moderate-heavy), temperatures will eventually raise through a process of latent heat.  To get a substantial ice storm, you need a nice steady precipitation rate with temperatures 30F or lower. 

From what I noticed, the High is moving quite a bit fast off shore like you said.  That's going to work against a major event. Precipitation needs to come in much sooner, but we will see on future runs.

Edit: I'd like to note areas like CLT/ATL could undergo major problems if the system even slightly over-performs.  A few years ago, ATL got whacked during rush hour due to something not too-well forecast involving icing.  It doesn't require much ice at all to paralyze a big city.

 

[Shawn]

Looking over the 18z GFS's ensemble member thickness & moisture profiles, there does not seem to be much support for precipitation arriving earlier or in larger amounts before the temps warm up.

 

[WeatherLC]

Looking over the 18z GFS's ensemble member thickness & moisture profiles, there does not seem to be much support for precipitation arriving earlier or in larger amounts before the temps warm up.

Doesn't the GFS typically have a bias for under doing QPF though?

 

[Shawn]

[quote author=Starburst link=topic=46.msg1637#msg1637 date=1481592324]
Looking over the 18z GFS's ensemble member thickness & moisture profiles, there does not seem to be much support for precipitation arriving earlier or in larger amounts before the temps warm up.

Doesn't the GFS typically have a bias for under doing QPF though?
[/quote]

I can't say anymore these days.  Last I heard, GFS was too aggressive/fast with precip.  It's all a blur.  But the majority of precip as a whole really isn't coming in (if at all) until the temps warm up.

Dont' get me wrong, there are a couple members with a substantial event, but nothing like "boom" or "scary" as you sometimes see in the individual members.

 

[SoutheastRidge]

I don't mean to be a party pooper, but I don't know if this little "event" is even worthy of its own thread.

 

[D-Ray]

need to watch the trends on how soon the precip gets here....its all about timing just like most storms in the southeast

 

[Shawn]

Was hearing about the Canadian ensembles being a bit icy.. saw some individuals and some were substantial into parts of GA.  Member 06 would be quite a problem for ATL.  Anyway, here they are from the 12z:

 

[Storm5]

I don't mean to be a party pooper, but I don't know if this little "event" is even worthy of its own thread.

of course it is. could have a large impact  area that impacts members of the board regardless  if it's just a few hours or not

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[Storm5]

00z gfs is way late with the precip . very little if any frozen precip

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[Snowflowxxl]

Yep, good bit less than 18z

 

[Shawn]

00z GFS OP looks about like the 18z ensemble members as a whole did.

 

[Supershow]

00z gfs is way late with the precip . very little if any frozen precip

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That's a pretty stout HP at 1044 in Iowa, growing to 1046 in NE MO -  why is the cold air so delayed?

 

[NCSNOW]

Try you some foreign guidance, it'll serve you better