• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Wintry February 19-21, 2020 Winter Storm

Forevertothee said:
GSP discussion

Not impressed at all....

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 335 AM EST Monday: While model guidance overall agrees on the
dry weather pattern for the weekend as sfc high pressure builds in,
disagreement continues for Thursday and Thursday night. Models have
already flip flopped a handful of times for this time frame, and it
seems to continue. With nearly zonal flow aloft and sfc high
pressure expanding across much of the northern CONUS, latest 00Z
ECMWF highlights plenty of moisture spread across the Gulf states
and Southeast, as a system moves near the area and eventually
offshore the Carolina coast. As colder air infiltrates into the
area, uncertainty unfolds in regard to precip type with this system
- rain, rain/snow, snow. Meanwhile, the GFS is somewhat similar,
though shows a much drier and slightly warmer trend for the FA.
Thus, given the discrepancy, have collaborated with neighbors, and
kept with light precipitation tapering off throughout the day on
Thursday. Mainly as all rain across the area, with rain/snow mix
becoming light snow showers across the NC mountains Thursday into
Thursday evening. For now, have kept QPF near zero.

With colder air expected for the end of the week, expect a warming
trend for the weekend, with normal to just above normal temperatures
on Saturday and Sunday.


Sent from my iPhone using Tapatalk
Click to expand...


They also weren't impressed with the event earlier this month and failed to issue even winter weather advisories for much of their CWA when warning-level criteria snow had already fallen.

¯\_(ツ)_/¯
 
I was hoping you would reply. I don’t want to sound like my backyard question but what are your thoughts on the Upstate chances here?


Sent from my iPhone using Tapatalk
 
LovingGulfLows said:
NAM looks like it could be good for a decent portion of N GA if the temp profiles are right. 850s crashing just as the precip is really getting going. 2m temps around 35-38. Future runs will be interesting.
Click to expand...
I'm definitely starting to go back on my thoughts about this being over for this area after the latest runs. They've trended better with the DPs surging in before the moisture arrives and I think they'll keep getting better since the time frame is shrinking. As Webb mentioned, the CAD aspect isn't handled well and the models may just now be picking up on it to some degree. It'll come down to the last 24 hours I think to see who and what areas will get something.
 
Forevertothee said:
I was hoping you would reply. I don’t want to sound like my backyard question but what are your thoughts on the Upstate chances here?


Sent from my iPhone using Tapatalk
Click to expand...

I don't think the chances aren't all that bad for those well north of I-20 w/ some of the initial overrunning precipitation, certainly can't rule out at least a quick burst of snow and/or sleet even down to the midlands if the rates are heavy underneath a frontogentically forced band of precipitation
Best chance for accumulating snow may actually end up being the I-95 corridor in NE SC towards Florence, Darlington, & Dillon, etc. if a legit coastal low forms, however that remains to be seen.
 
Even though it's the long range NAM which isn't always exactly reliable & while there isn't any precip falling in the model (yet) over NC, when you see low-mid level warm advection (warm colors) like that with frontogenesis (contours) superimposed over the dendritic growth zone (locations where it's -10C to -20C), there's a pretty strong case to be made that we could see some significant moderate-heavy banded precipitation w/ this storm, the only hinderance to this being that the low-levels will initially be pretty dry. However, I think if this 700mb temp advection & frontogenesis forecast generally verified, there would be more than enough forcing for ascent to easily overcome it.

Now that we've started to settle in on a pattern that'll be generally conducive to overrunning, this is definitely the type of storm that usually overperforms and trends wetter & further north down to the very last second.

namconus_temp_adv_fgen_700_seus_53.png
 
Webberweather53 said:
I don't think the chances aren't all that bad for those well north of I-20 w/ some of the initial overrunning precipitation, certainly can't rule out at least a quick burst of snow and/or sleet even down to the midlands if the rates are heavy underneath a frontogentically forced band of precipitation
Best chance for accumulating snow may actually end up being the I-95 corridor in NE SC towards Florence, Darlington, & Dillon, etc. if a legit coastal low forms, however that remains to be seen.
Click to expand...

The last panel of the NAM alludes to heavier precipitation working in as a very cold rain. But the interesting part about this area, is the model trend maps show lower and lower temperatures (even before the precipitation actually starts in the Midlands), and 850's also falling by 1c or so versus previous runs.

Basically, heavier precipitation moving in with 850 right around 1c, continuing to cool down on the NAM runs.

Edit: I do know the Euro runs a bit too warm in many cases, the NAM too cool, but the GEFS ensemble members may be telling. We knew the moisture would likely be more expansive, and I was looking closer at the southern jet yesterday, and those waves are wanting to consolidate/get a bit stronger on some reliable guidance. A nightmare to forecast, ESPECIALLY if we are talking about any kind of coastal trying to get going as a result.
 
Webberweather53 said:
Even though it's the long range NAM which isn't always exactly reliable & while there isn't any precip falling in the model (yet) over NC, when you see low-mid level warm advection (warm colors) like that with frontogenesis (contours) superimposed over the dendritic growth zone (locations where it's -10C to -20C), there's a pretty strong case to be made that we could see some significant moderate-heavy banded precipitation w/ this storm, the only hinderance to this being that the low-levels will initially be pretty dry. However, I think if this 700mb temp advection & frontogenesis forecast generally verified, there would be more than enough forcing for ascent to easily overcome it.

Now that we've started to settle in on a pattern that'll be generally conducive to overrunning, this is definitely the type of storm that usually overperforms and trends wetter & further north down to the very last second.

View attachment 34857
Click to expand...
Are you talking about them purple lines on the map where heavy banding will setup I’m trying to learn how to read this map
 
  • Like
Reactions: D^2
Webberweather53 said:
Even though it's the long range NAM which isn't always exactly reliable & while there isn't any precip falling in the model (yet) over NC, when you see low-mid level warm advection (warm colors) like that with frontogenesis (contours) superimposed over the dendritic growth zone (locations where it's -10C to -20C), there's a pretty strong case to be made that we could see some significant moderate-heavy banded precipitation w/ this storm, the only hinderance to this being that the low-levels will initially be pretty dry. However, I think if this 700mb temp advection & frontogenesis forecast generally verified, there would be more than enough forcing for ascent to easily overcome it.

Now that we've started to settle in on a pattern that'll be generally conducive to overrunning, this is definitely the type of storm that usually overperforms and trends wetter & further north down to the very last second.

View attachment 34857
Click to expand...

To add to this the NAM has been trending north with our rain system in a couple of days.

I won’t be surprised at all to see this trend a bit more NW and wetter with time615FA434-9F45-4702-94C0-5189764A4C81.gif
 
Yeah I think ENC is in the primo spot but also expect an increase expanse North of the Precip . Would not be at all surprised if SVA doesn't get into the act here. Remember the comment Webb made about orographic lift, it could be a big factor in Northern and Western areas of NC and perhaps NWSC
 
Well, continuing to see a stronger coastal deal on modeling today would make sense. The Euro had this idea very first and backed off, but as we get closer the waves in the Southern stream are being seen better. Sure, 500mb has had little changes here and there, as a whole, but over all it's kind of been figured out for the most part (the players on the field), what has not been figured out is just what can come of the strength of some of these waves in the jet itself.

I saw a much more potent look to a wave on the 18z EPS mean last night, and I am continuing to monitor it. It could have a major surprise up it's sleeve and I would expect shorter range modeling to handle the strength of it better as we get closer.

Again, 500mb's basic setup has been forecast decently, but those waves .... we should start to get a clearer picture in the next couple of days in regards to that and a potential coastal.
 
Brick Tamland said:
That is pretty much where we want the moisture to show now before the NW jog. Looks like a classic setup for the eventual NW movement.
Click to expand...

Explain in meteorological terms what the eventual “NW” movement is? Because as I understand it, there is no such thing as a “NW” movement, it’s a correction of sampled modeling, so saying a NW movement means that it physically moves NW. or are you just parroting?
 
Last edited:
You must log in or register to reply here.
Back
Top