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Wintry Dec 8-10th Winter Storm

18z runs in general had a stronger ull which flipped RDU sooner. But good news is most models are showing front end snow. See if 0z continues with stronger ull.
 
SoutheastRidge said:
NWS has 5-11" for Charlotte. I take it some of you think that's too high ? I see Webber has 1-3 for Charlotte LOL. What does Webber see that the NWS doesn't ?
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A 50-60+ KT jet at 700 hPa coupled to large amounts of QPF often leads to the warm nose being stronger than forecast and the heavier precipitation rates can lead to the creation of an in-situ dome (superimposed onto the larger-scale CAD) that accelerates the end of the warm nose aloft in the downwind direction as considerable latent/sensible heating is deposited onto where the warm nose is strongest while cooling occurs below the level of maximum heating aloft. Another obvious caveat with the models is they don't have sufficient vertical resolution, the proper mixing schemes, and pretty crappy convective parameterization schemes to account for all of the above, thus leading to weaker warm noses than forecast (& often the low-level cold dome is weaker than reality in these same models).


This profile on the NAM while taken at face value (bad idea) is all snow near RDU, that's an absurd amount of mid-level veering and warm air advection above the CAD dome. Apart from all of the above, I've been burned many times the last several years figuring the models would have a good handle on this feature, and figured the warm nose wouldn't be that strong, it's usually a good idea to go a few degrees warmer near the height of the warm nose in situations like this and that favors less snow and more mixed phase precipitation in areas like Charlotte and Raleigh, this could end up being a respectable ice storm for someone in/around these areas.
The NWS GSP snow forecast of 5-11" here is likely way out to lunch (shocker) and assumes more of the precipitation will fall of snow here, the main precipitation type is liable to be sleet.

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