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Wintry Feb 17-19 Smastsmasher Snow/Ice

Cardall07 said:
I am confused. The NAM total snow accumuations looks like this, only when you watch the radar it does not show any real frozen precip moving through my area (Dalton, Ga.). I'm really just looking for someone to explain to me why it looks like North Georgia has accumulating snow/sleet when the radar shows only rain.
View attachment 75811
Click to expand...

Because only certain temperatures are put into that algorithm to make snow output. The SLR 10:1 ratio map that says **includes sleet** at the top of it is not seeing the warm nose. Same reason then 3KM nam has the Piedmont of NC getting 9” snowfall when we are expecting an ice storm with zero snow.

Read this: https://home.pivotalweather.com/guides/snowfall


Sent from my iPhone using Tapatalk
 
Cardall07 said:
I am confused. The NAM total snow accumuations looks like this, only when you watch the radar it does not show any real frozen precip moving through my area (Dalton, Ga.). I'm really just looking for someone to explain to me why it looks like North Georgia has accumulating snow/sleet when the radar shows only rain.
View attachment 75811
Click to expand...
I think it is because that TT map attempts to count qpf that is freezing rain and sleet as snow. Try Pivotal Weather.
 
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Cardall07 said:
I am confused. The NAM total snow accumuations looks like this, only when you watch the radar it does not show any real frozen precip moving through my area (Dalton, Ga.). I'm really just looking for someone to explain to me why it looks like North Georgia has accumulating snow/sleet when the radar shows only rain.
View attachment 75811
Click to expand...

The tropical tidbits snow maps are trash, I recommend using the pivotal weather maps which take into account what is actually falling as snow. The kuchera snow map is better to use on there vs the 10:1 map also.
 
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Latest snippet from discussion forecast from GSP:

.NEAR TERM /THROUGH TONIGHT/...
As of 935 AM: No significant changes to forecast thinking for
now. Question remains how far south does the cold air move and how
far south can the freezing wet bulb temps make it when precip
develops. Current Warnings/Advisories still look well placed;
however, could see small ice accums farther south into the Advisory
counties than currently forecast. Stay tuned for the latest updates.
 
Myfrotho704_ said:
Eh the NMMB (which has done extremely well and doesn’t have a cold bias like the WRFs do) looks the most accurate, looks just like the 3km NAM View attachment 75821
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Ehh the WRF did well with the last storm we have and although I don't think we will get down to 26-28 degrees but this has a bust for a colder solution written all over it. A continued supply of cold air over snow pack and the 3K NAM is already underestimating just how dry the airmass over us is currently. Personally I think all of those solutions are on the table for this.
 
Jon said:
Because only certain temperatures are put into that algorithm to make snow output. The SLR 10:1 ratio map that says **includes sleet** at the top of it is not seeing the warm nose. Same reason then 3KM nam has the Piedmont of NC getting 9” snowfall when we are expecting an ice storm with zero snow.

Read this: https://home.pivotalweather.com/guides/snowfall


Sent from my iPhone using Tapatalk
Click to expand...
Thanks! That makes a lot more sense now!
 
iGRXY said:
Ehh the WRF did well with the last storm we have and although I don't think we will get down to 26-28 degrees but this has a bust for a colder solution written all over it. A continued supply of cold air over snow pack and the 3K NAM is already underestimating just how dry the airmass over us is currently. Personally I think all of those solutions are on the table for this.
Click to expand...

Yeah, DP are running a good couple of degrees below what models had us out. We're still at 19. This has overperformance written all over it. I still think area's from CLT-RAH are going to surprised as to how much ice may fall. Which, as we all know is NOT a good thing. We're entering now time when it comes to forecasting.
 
GaWx said:
"Hail" at DFW at 2 AM lol:

200 AM CST WED FEB 17 2021

NOTE: "FAIR" INDICATES FEW OR NO CLOUDS BELOW 12,000 FEET WITH NO
SIGNIFICANT WEATHER AND/OR S TO VISIBILITY.

TXZ118-119-170900-
DALLAS/FORT WORTH METROPLEX

CITY SKY/WX TMP DP RH WIND PRES REMARKS
DFW AIRPORT HAIL 19 17 92 E3 30.11R FOG
Click to expand...

That's how our graupel episodes were reported during an even we had here last month...
 
Myfrotho704_ said:
RGEM Looks more like the 3km now, models finally starting to agree View attachment 75843
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The one interesting thing it has is the secondary hit of freezing rain Thursday night into Friday morning. I would normally discount this as its cold bias but RAH also mentions a chance of freezing rain tomorrow night (for some).
12z Friday:
aaab.JPG
 
hope this holds true tonight
 

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Myfrotho704_ said:
I wanna bet these high clouds move out and a lot of us warm 2-4 degrees past the forecasted temp then clouds move in later and things retreat north a tad
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Meh, I don't think they will warm that much. The clouds will move out but it has limited warming to some degree. I am more focused on DP's which are running lower than anticipated.
 
Myfrotho704_ said:
Here’s what I’m thinking looking at the FRAM ice map, most of the stuff south of the dashed line is mostly rain (maybe spotty light ice), north/inside of the red line is the bad stuff, and in between is the lighter ice View attachment 75853
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I think the areas hit hardest last time and those impacts move south towards Raleigh and maybe Charlotte but they may be too far south ... the next level of ice storm seems to effect the areas that got hardest hit last time .. ugly stuff
 
NickyBGuarantee said:
I think the areas hit hardest last time and those impacts move south towards Raleigh and maybe Charlotte but they may be too far south ... the next level of ice storm seems to effect the areas that got hardest hit last time .. ugly stuff
Click to expand...
Probably gonna be where north Charlotte/north, northwestern Raleigh has some visible ice while the southern parts it doesn’t even look like it did anything
 
GSP
As of 935 AM: No significant changes to forecast thinking for
now. Question remains how far south does the cold air move and how
far south can the freezing wet bulb temps make it when precip
develops. Current Warnings/Advisories still look well placed;
however, could see small ice accums farther south into the Advisory
counties than currently forecast. Stay tuned for the latest updates.
 
Myfrotho704_ said:
Here’s what I’m thinking looking at the FRAM ice map, most of the stuff south of the dashed line is mostly rain (maybe spotty light ice), north/inside of the red line is the bad stuff, and in between is the lighter ice View attachment 75853
Click to expand...

Looks about right with your edits. The furthermost North counties in SC may see a bit, but nothing like NC is going to end up as. That national blend is a little bit overzealous because of a rogue member or two. I'm not even sure Charlotte sees much of any ZR at this point.
 
We are entering the time frame where models, while helpful are not necessarily the answer. We are in now casting time. Even GSP alluded to the wetbulb, etc. And while the sun came back out that could also cause us to drop more tonight before clouds move in. If you look at the visible satellite, the main system is still pretty far out.
 
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