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Wintry January 3rd-6th, 2018 Winter Storm The ARCC/Xtreme Weather Special

I keep following up with NWS GSP, to see what changes they make to their Forecast Discussion. As of their most recent one, it's very intriguing. They are well versed, conservative and not bullish at all in their approach. So, makes you wonder, when they say things like that in the AFD.
 
Well KCAE finally updates to this:
000
FXUS62 KCAE 031025
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
525 AM EST Wed Jan 3 2018

A vigorous mid level short wave seen on water vapor diving
southeast across Mississippi and Louisiana. A distinct
baroclinic leaf is also evident in IR imagery. Northern stream
short wave is diving southeast into the Mississippi valley. As
expected phasing of these troughs will occur over the
Southeastern States resulting in cyclogenesis off the Florida
coast. Surface analysis at 09z indicates pressure falls off the
east coast of florida to offshore South Carolina. The models
have been consistent with surface low developing off the florida
coast then deepening rapidly as it tracks to the northeast.
Some models have surface low closer to the South Carolina coast
and the pressure falls near CHS are a concern. The ECMWF has
been consistently further to the east. The latest trends have
suggested more moisture in the 850mb-500mb layer will spread
further inland increasing the threat for precipitation (snow)
at least in the east Midlands. Even the drier GFS has sufficient
moisture in the snow growth zone across the east with strong
upward vertical motion as the surface low deepens and the upper
trough moves through in the afternoon and early evening. In fact
the omega appears to be above the snow growth zone suggesting
higher snow-liquid ratios than climatology.

Some higher resolution guidance this morning is suggesting
higher snow amounts but putting more weight on the
deterministic ECMWF/GFS and their ensembles since they have been
consistent. Lower confidence remains for areas to the west
where precipitable water should be lower...however dynamics may
be strong. So will raise pops. Based on the latest data...
confidence is now high for significant accumulation in the I-95
corridor. Will post winter storm warning in that region with
accumulation around 2 inches. A winter weather advisory will be
expanded to adjacent counties. A dusting or light accumulation
is possible in other regions. Temperatures will struggle to go
above freezing with some potential for evaporation
cooling/diabatic effects due to dry low levels. Trended
temperatures today below Mos consensus especially east. Behind
the trough tonight expect rapid clearing from southwest to
northeast with temperatures falling back into the teens and low
20s.
 
DLI4SCwx said:
I keep following up with NWS GSP, to see what changes they make to their Forecast Discussion. As of their most recent one, it's very intriguing. They are well versed, conservative and not bullish at all in their approach. So, makes you wonder, when they say things like that in the AFD.
Click to expand...

I hear ya. CAE's that I posted above is different sounding, but I highlighted some important parts. I think a lot of forecasters are more of a "lets see what happens and adjust" for this scenario.
 
Shawn said:
I hear ya. CAE's that I posted above is different sounding, but I highlighted some important parts. I think a lot of forecasters are more of a "lets see what happens and adjust" for this scenario.
Click to expand...
Ditto. I interpreted it just as you said it as well. They are in a wait and see approach, as we all are at this time. They are playing it cautiously, as they should be at this time.
 
DLI4SCwx said:
Ditto. I interpreted it just as you said it as well. They are in a wait and see approach, as we all are at this time. They are playing it cautiously, as they should be at this time.
Click to expand...

I think we sent our salt and equipment to the coast.....:eek:
 
I see that the models have increased their precipitation amounts for the CAE area. It will be interesting to see if this is just noise on the models or will a lot of people be caught off guard.


Sent from my iPhone using Tapatalk
 
Shawn said:
I think we sent our salt and equipment to the coast.....:eek:
Click to expand...
I know they are in the most primed position to get in on the action. But, they should still have contingency plans in place and have some of that equipment and salt still here. I'm sure they do, but assisted the folks down on the coast to the extent they could.
 
DLI4SCwx said:
I know they are in the most primed position to get in on the action. But, they should still have contingency plans in place and have some of that equipment and salt still here. I'm sure they do, but assisted the folks down on the coast to the extent they could.
Click to expand...
Likely already talked to areas in GA & Upstate for help, incase.

Getting ahead of ourselves anyway; off a GSP discussion and NAM run with 2-3 inches around here. lol
 
The folks at NWS CAE will be conservative always. And normally when they are, they are right. But this time, I don't think they are. I think we get some snow out of this. Everything is trending favorable for us and the storm is today. Has all the makings of a surprise hit.
 
Robert West said:
The folks at NWS CAE will be conservative always. And normally when they are, they are right. But this time, I don't think they are. I think we get some snow out of this. Everything is trending favorable for us and the storm is today. Has all the makings of a surprise hit.
Click to expand...
I love that they are being so conservative. I'd rather them bust on the lower side rather than the higher side of things. I'm just looking for every little sign that can help us in this situation. We just need to keep the West trends going!
 
DLI4SCwx said:
I love that they are being so conservative. I'd rather them bust on the lower side rather than the higher side of things. I'm just looking for every little sign that can help us in this situation. We just need to keep the West trends going!
Click to expand...
Theyre a lot of signs that point for snow for us today
 
Under a WWA. Just calling for an inch here. Doesn't seem like it will be a big storm. Even the NAM is backing down the totals now. Get a great track but still can't get the precip.
 
Webberweather53 said:
The globals are definitely adjusting NW, but I don't think they're ever gonna truly see this one coming for those west of I-95 in NC... They can't resolve the intense diabatic heating on the NE Gulf coast and thus will probably end up too far SE
Click to expand...

Webberweather53 said:
It's still not going to be enough imo, hopefully other mets realize this too but I doubt it
Click to expand...

Webberweather53 said:
Yeah I'm sticking to my guns and the actual dynamics in play here plus historical precedence wrt previous winter storms in NC and how poorly the models handled them (esp the mid-level WAA and extent of the precip NW of the low center), and this event will probably bust wetter and warmer in general vs the globals (obviously that could mean colder in those w/ more precip) as we've seen time and time again the past several years. My forecast is definitely out there against others but you don't have to look very far back to see how I've done against reality. Just as recently as Dec 2017, even when many of the models were plastering RDU & Chapel Hill a few days out, I adjusted everything NW and focused the heaviest snows in the highest elevations of the mountains... Sure, you could argue that maybe my forecast wasn't that great, but the NWS and most others at the time had a bullseye over the Triad or just east of there and we all know how that panned out in the end
View attachment 2588

Reality...
View attachment 2589
Click to expand...

I hope you're right. The models don't look good for us inland.
 
Looking at radar for Valdosta and it looks like its snowing farther west than predicted right? And what about all the blue in north Ga? Chris, I think your right! Ya may see a few flakes! My Macon peeps will be excited. Wow
 
ruh roh. if we aren't neutral tilt, we are very close to it based on wv imagery right at the ms/al border.

that leaf set up earlier could throw a major kink into some forecats, further downstream into GA & SC.
 
Shawn said:
ruh roh. if we aren't neutral tilt, we are very close to it based on wv imagery right at the ms/al border.

that leaf set up earlier could throw a major kink into some forecats, further downstream into GA & SC.
Click to expand...
Sure looks neutral, about to go negative.... should see explosive development within hours. I maybe wrong but reading GSP AFD, seeing WV loop and pressure falls along coast I think the slp organizes/consolidates early and we don't have that jumping around the models were struggling with.... gonna be a fun day
 
GSP NEW:

000
FXUS62 KGSP 031141
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
641 AM EST Wed Jan 3 2018

.NEAR TERM /THROUGH TONIGHT/...
As of 630 AM EST: The latest RAP/NAM/SREF runs have become a
touch more aggreessive on the snow potential for at least the
eastern half of Union County late today, and this has been wokred in
the 12Z update for PoP/Wx/QPF. Otherwise, today`s snow forecast for
our piedmont locations remains uncertain as concern exists over the
southern tier U.S. wave sharpening up and acquiring a negative tilt
more quickly than depicted by the operational models. Currently,
water vapor imagery shows the amplified system already acquiring a
neutral tilt as it moves into western Alabama. Additional height
falls are indicated upstream over the plains and the fear persists
that an injection of cold and dry air into the back of the trough
axis will deepen the feature more sharply and farther west than
indicated by the models. This would result in snowfall being
produced farther inland than featured in the operational models,
possibly across a good chunk of our forecat area. At any rate, we`re
getting set up for a cold day, with temps largely in the teens in
most areas early this morning, but with little opportunity for
insolation today as the mid and high clouds are already thickening
up from the southwest.

Concern is growing that the system will complete the transition to a
neutral tilt over AL/GA, then become negatively tilted crossing the
western Carolinas. Upper jet divergence ahead of this feature should
sharpen up very quickly over the central piedmont of the Carolinas
from 18Z to 21Z and a robust region of deep layer Q-vector
convergence will likely cross the area as well. Meanwhile, the
associated surface reflection will likely develop near the north
Florida coast and then deepen northward over the coastal waters of
the Carolinas. All of these features may well come together to
provide just enough moisture, and improving forcing, for snow
showers to develop mainly southeast of Charlotte. This could lead to
some quick accumulations of snow on the very cold ground, especially
over Union County NC this afternoon and early this evening. The
current feeling is that any strong frontogenesis bands will set up
east of the forecast area, so we shouldn`t be looking at any heavy
convective rates in our forecast area - unless the aforementioned
slower and more westward trends accelerate. Radar trends will need
to be monitored closely today for a short fuse SPS or winter weather
advisory should any snow showers threaten the lower piedmont.
 
Shawn said:
ruh roh. if we aren't neutral tilt, we are very close to it based on wv imagery right at the ms/al border.

that leaf set up earlier could throw a major kink into some forecats, further downstream into GA & SC.
Click to expand...
This possiblity was mentioned in GSP's discussion and im looking forward to what may happen upstream here. My temps rose 4° and dewpoints rose 7° since 3:30am.
 
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