The December to Remember 7th-8th blue turd winter threat thread.

[franklin NCwx]

7 minutes ago, mackerel_sky said:

Temps, temps, and temps!

Qpf, qpf,  and qpf

[burrel2]

A nice band of snow showing up on the Hi-res NAM around lunchtime Friday up the I-85 corridor in SC. If it plays out like this I think the upstate could get a quick inch or two of snow as the heaviest burst comes through.  Both the Hi-res NAM and RGEM are really slow to change over from rain to snow here, which I don't understand looking at the soundings. From what I see we should flip over to snow relatively quickly once rates pick up. We'll find out I guess.

[lilj4425]

4 minutes ago, burrel2 said:

A nice band of snow showing up on the Hi-res NAM around lunchtime Friday up the I-85 corridor in SC. If it plays out like this I think the upstate could get a quick inch or two of snow as the heaviest burst comes through.  Both the Hi-res NAM and RGEM are really slow to change over from rain to snow here, which I don't understand looking at the soundings. From what I see we should flip over to snow relatively quickly once rates pick up. We'll find out I guess.

GSP has us going over to snow at lunch time then back over to rain in the afternoon-evening before going back over to snow around 10-11pm.

[FallsLake]

43 minutes ago, PGAWx said:

From NWSRal:

This 4 AM EST surface analysis reveals one of the prohibitive factors for appreciable measurable snow in cntl NC. The weak ridge of high pressure from TX to NC is not sufficiently cold/dry to support much snow; and the upstream arctic front will be blocked by the Appalachians. 

If we can get a dusting or a half inch of slush, consider that a victory.

 

Here's RAH's discussion from last night:

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 425 AM Thursday...

...Some wet snow is still possilbe across portions of Central
NC Friday night and early Saturday although accumulations will
be limited...

An amplifying trough extending from eastern Canada southwest
through the Great Lakes/Ohio Valley into Texas on Friday
morning will shift east and approach the Southeast coast by
Saturday evening. At the surface, a stationary front extending
from northern FL northeast just off the Southeast coast lingers
through Saturday with a couple of surface waves of low pressure
developing and riding up along the front. A secondary cold
front with a surge of slightly colder and drier air settles into
VA and evntually northern NC from the north on Friday.

The persistent southwesterly flow aloft originating in the western
Gulf of Mexico with deep moisture including precipitable water
values of 1.5 inches or more and multiple disturbances riding
northeast will produce a long ribbon of precipitation across the
northern Gulf to the Southeast coast. As disturbances aloft
move up the coast near the baroclinic zone off the coast, the
precipitation shield will buckle northwest across most of the
central NC including the Piedmont on Friday and Friday night.
The most widespread precipitation and greatest precipitation
amounts will be across the coast with 72-hour model consensus
QPF amounts ranging around 1.5 inches in the southern Coastal
Plain near Goldsboro, with around an inch from Southern Pines
northeast to near Raleigh up to Roanoke Rapids. There will be a
sharp gradient in the precipitation amounts across the
northwestern edge of the precipitation shield with amounts of
0.1 to 0.25 in the Triad.

While anticipating the precipitation amounts across the
northwestern colder edge of the precipitation shield is
challenging enough, handling the mixing with/change to wet snow
and then accumulation potential is problematic. The big picture
using pattern recognition screams that a lack of a strong
cold/dry high pressure system in a favorable position prohibits
a higher impact snow accumulation event. What is more likely
are narrow, southwest-northeast elongated snow islands where a
cold enough boundary layer meets the precipitation axis and
produces some snow accumulations.

Partial thickness values and forecast BUFR soundings suggest
precipitation on Friday will generally be a cold rain as snow
falling aloft melts as it enters a warmer boundary layer where
air temps are in the mid to upper 30s in the lowest few thousand
feet. With time during the day, the warmth in the boundary
layer will cool and toward evening, the precipitation across the
interior Piedmont will increasingly mix with and then change to
snow overnight with the wet snow area expanding southeast. It
typically only takes a wrinkle or two to sabotage snow forecast
in central NC or to decrease the snow accumulation efficiency,
and there are a lot of potential issues with this event including
a lack of cold/dry air, a warm boundary layer, warm ground
temperatures and questions about how far northwest the
precipitation will extend.

In the end, we still expect some light snow accumulations,
certainly less than an inch and generally a dusting, will
occur west of U.S. Route 1, mainly across elevated and grassy
locations. The greatest amounts will likely occur in the I-85
corridor from Burlington northeast to the VA border. It is not
out of the question that a couple hour burst of heavier
precipitation rates could produce some localized greater amounts
up to an inch or possibly two, but that is a low likelihood
outcome. The precipitation will end from west to west Saturday
morning, perhaps lingering into the early afternoon near the
I-85 corridor as some light rain.

Highs on Friday will only be in the lower 40s (may stay in the
upper 30s in a few spots) with lows Friday night in the 30 to
36 range by Saturday morning. It`ll be chilly on Saturday with
highs in the lower 40s. -Blaes

&&
 

[FallsLake]

Elizabeth Gardner from WRAL.

http://www.wral.com/weather/video/17167486/

 

 

[PackGrad05]

It is exciting because it is the first event of the season for a lot of us, but I agree with her statements.  Fun to see snow flakes flying, but I'm not cancelling any of my saturday plans because of it.  

[FallsLake]

The euro would be nice; particularly for the RDU folks. It also shows potential events in the LR.

http://wx.graphics/models/ecmwf/ecmwf_usa.php

 

[Blue_Ridge_Escarpment]

03Z SREF really amped. Showing 4-6 in SW NC

[odell.moton]

03Z SREF really amped. Showing 4-6 in SW NC

What’s its showing for upstate Sc


.

[Blue_Ridge_Escarpment]

3 minutes ago, odell.moton said:

 

 

 

What’s its showing for upstate Sc


.

 

 

 

It's such a tight gradient so it's hard to explain. Picture can explain better lol. 

[mrdaddyman]

Does anyone know whether the "Snow Depth" output or the "Kuchera" output on the model maps is more accurate? It's very confusing because the Snow Depth output is often more than the "Kuchera" output for the same time period. Are they just 2 separate methods that are calculated differently or are they supposed to be related somehow? Any ideas from you veterans?

[Jonathan]

8 minutes ago, Blue_Ridge_Escarpment said:

03Z SREF really amped. Showing 4-6 in SW NC

Wow, yeah. SREF is juicy. Probably the most juiced run its had.

[wncsnow]

New SREF will be out soon

[PGAWx]

Barely any discussion on the overnight euro.  That 0z NAM really took the wind out of everyone's sails.  

[snowlover91]

19 minutes ago, mrdaddyman said:

Does anyone know whether the "Snow Depth" output or the "Kuchera" output on the model maps is more accurate? It's very confusing because the Snow Depth output is often more than the "Kuchera" output for the same time period. Are they just 2 separate methods that are calculated differently or are they supposed to be related somehow? Any ideas from you veterans?

Usually the Kuchera gives a little more accurate pictures, and even then I don't think it factors in ground temps and such. The Kuchera does a better job assuming ratios based on the atmosphere/dynamics and doesn't just default to the 10:1 that the snow depth and other maps seem to use. Since this will be a heavy wet snow, ratios will be pretty low around 5:1 or so.

[Wow]

NW trend with the SREF

[J.C.]

SREF mean for ATL is 1.5" and GSP is 1.89"

[DopplerWx]

this will be killer for snow chances just like last year, another snowstorm a couple thousand feet up. going to be very difficult to overcome a 3c warm nose.

 

Jonathan Blaes @jlblaes 5 minutes ago

Snow lovers, Rut Roh! The 12/07 06Z NAM BUFR forecast for KRDU is picking up on a developing warm nose Friday night. At 2am, snow aloft is falling but likely melts in the ~3C warm nose near 775 mb. The +2C surface temp and warm ground limit accumulations. #ncwx

[packbacker]

11 minutes ago, Wow said:

NW trend with the SREF

GEFS still in the slow down and closer to coast mode...

 

 

[griteater]

4 minutes ago, packbacker said:

GEFS still in the slow down and closer to coast mode...

 

 

Looking at the isobars there, you can see how Alabama and Georgia have more northerly wind component trying to feed in cold air...whereas SC and central NC are struggling in that department

[Buddy1987]

11 minutes ago, packbacker said:

GEFS still in the slow down and closer to coast mode...

 

 

Man crazy to watch the trough take a bend backward in the last frame there, in an attempt to try and go neutral. 

[packbacker]

1 minute ago, Buddy1987 said:

Man crazy to watch the trough take a bend backward in the last frame there, in an attempt to try and go neutral. 

To bad...if that piece of energy diving in over Wisconsin was diving in over Minn it might be different.  

[packbacker]

For Raleigh this sure is a cruel way to start this winter after last January bust....NAM/GFS both shows 30 hours of mid/low 30's of really cold rain.  

http://68.226.77.253/text/MESOSFC/NAM_Krdu.txt

[griteater]

Here are the Charlotte surface observations from the Nov 2000 storm.  It probably won't be this cold, but similar setup relying on precip to cool the lowest warm layer in the atmosphere

http://mp1.met.psu.edu/~fxg1/NARR/2000/us1119.php

[Buddy1987]

10 minutes ago, packbacker said:

To bad...if that piece of energy diving in over Wisconsin was diving in over Minn it might be different.  

I still think that the "digginess" involved with the northern stream energy is somewhat stronger than progged and may have some type of adverse affect on the tilt of the trough. It seems to be responding to that energy if you examine 5h closely.

[Buddy1987]

Lol the NAM is trying again at 30 to tilt the trough more neutral. Don't know if it will manage in time to have any meaningful affect for all of us.

Edit: Much better expansion of qpf in western and northwestern MS/AL

[FLweather]

7 minutes ago, Buddy1987 said:

I still think that the "digginess" involved with the northern stream energy is somewhat stronger than progged and may have some type of adverse affect on the tilt of the trough. It seems to be responding to that energy if you examine 5h closely.

I agree looking at WV loop. That one Tiny piece of Shortwave energy diving southwest from CO to NM to AZ may help keep the energy more consolidated. Not ATM outwest shows a major wrapped up closed h5 from TX to NC. But maybe stronger in sense.  Last few frames looks like its wetter maybe more NW push of moisture over TX and NM

[franklin NCwx]

Nam looking great

[Buddy1987]

3 minutes ago, FLweather said:

I agree looking at WV loop. That one Tiny piece of Shortwave energy diving southwest from CO to NM to AZ may help keep the energy more consolidated. Not ATM outwest shows a major wrapped up closed h5 from TX to NC. But maybe stronger in sense.  Last few frames looks like its wetter maybe more NW push of moisture over TX and NM

The northern energy diving out of Canada this run is not impinging as much on the trough, allowing it to bend back some. This run has that energy a little more northwest of where it was on 6z. Interesting to see what affect this has in upcoming frames.

[Buddy1987]

Nam at 36 has some light precip showing up in eastern TN now. The base of the trough is really trying to take a swing here now.