Good morning folks, here is an update on the upcoming weather events.
December 29th Event
The event looks to be on track and is lining up with what was discussed yesterday. The lack of a cold high pressure in the Northeast and the fact that this current cold air mass is weakening and eroding means that this event is going to be rain it appears outside the mountains. It is possible that the precipitation could start as a mix of rain/snow late tonight across parts of the foothills, particularly the counties near the Virginia border, but a quick change to rain should occur even if this happens. Most of the model data I have seen shows a 1-4 inch type snow event in the mountains mostly above 2500-3000ft with some areas also seeing a wintry mix overnight. It shouldn’t be a big deal but another reminder that we are in winter. East of the mountains just a cold rain later tonight and tomorrow.
The models have come into a little better agreement today on the scenario during this time frame although significant uncertainty continues. Almost all of the model data shows a 2 pronged scenario. The first impulse will move into California tomorrow, with a 2nd impulse in the Pacific hot on its heels. This will force this first impulse to eject quickly into the southern Plains and Deep South and it looks like this system will spread precipitation into the mid-Atlantic/Southeast by New Year’s Day. It looks like the precipitation type corridors will likely line up based on the track of the weak area of low pressure.
It appears most models/ensemble members show now potential from Virginia to Kentucky and north into the Ohio Valley. The QPF is light but several inches would be possible. South of this it looks like mostly rain for NC/TN although it is close. Some of the ensemble members show snow/wintry mix, but the best bet right now is rain.
Part 2 of this even is more uncertain, as the 2nd impulse eject out across the southern Plains/Gulf Coast. The models are oscillating from cycle to cycle on this being a suppressed event with many not seeing much to a more westward event. In my opinion this looks like another overrunning event where we will not see a strong storm system but a weak low moving ENE across the Southeast to off the Southeast coast. The question is what is the exact track and will the northern stream provide enough cold air for this to be a wintry event. It looks like we may see a cold high pressure sliding into the Northeast as this event beings around 1/3 or so. The Euro Ensemble mean shows a couple inches of snow from NC northward, but the operational model is a cold rain. The 6z GFS and many of its members are now suppressed with this system showing it offshore. The 00z Canadian had a light wintry event for NC. I think the potential remains around 1/3 or so for a wintry event as far south as NC/TN but much will depend on the timing of the northern stream and this southern stream impulse, as usual J
Stay tuned that is how it looks for now.