#Savannah, Coastal GA/SC to #Freeze this weekend

First, if you’re looking for a white Christmas, you’ll have to go to Tennessee … here is the forecast for Sunday morning:

Atlanta will still be the usual mad max wasteland, just without the snow. (note at bottom of post)

The big issue for coastal GA/SC will be several days of freezing overnight temperatures, with not much warming in between. Throw in some wind chill, and it will be the first serious cold snap of the year, and despite the fact folks in Minnesota would laugh at this, hazardous for those not used to it. Here is the wave of arctic air sweeping across the region …

click to embiggen.

In downtown Savannah, after rain mid week on Friday the temperature will drop continuously all day – nearly 40 degrees, from near 60F pre-dawn to near 20F by sunrise Saturday. A particular problem will be the wind chill – it will be windy, gusting into the 30mph range in the afternoon, but overnight is when it will be borderline dangerous, with a wind chill temperature near 10F by 4am Saturday morning. While the static air temperature will rise to the upper 30’s during the day, the wind chill will likely not go above freezing Saturday. At least the winds should drop off by evening, but overnight lows will still be in the 20’s and wind chill in the teens. Christmas Day (Sunday) may hit 40F, but again overnight Sunday the static air temperature will go below freezing again and wind chill in to 20’s. Here is the forecast graph for Daffin Park – you can click to go to the NWS Charleston forecasts and click on the map for other sites to get the details (including outside the Savannah/Low Country area):

click to go to NWS forecast pages.

So those are the raw numbers, what does it mean? The first thing people should think of are outdoor pets and animals. They need to be protected – brought in if at all possible. Any fragile plants that can be brought in probably should – just covering them won’t be enough for exposed potted plants, with multi-day freeze with wind. Stuff planted in the ground that are covered should be exposed during the following day to allow for evaporation – otherwise the trapped moisture will likely freeze the next night and cause more damage.

What about pipes? Any outdoor hoses or irrigation systems should be drained. Soil temperatures are still warm, so that will help anything buried over an inch or so should be ok, and we won’t get a ground freeze, but the wind means anything exposed – including pipes that run under houses with crawl spaces – will be getting pretty cold by Sunday night. So it does make sense to drip them. You don’t need a torrent, just enough to keep the water moving. Also keep in mind that many homes around here run pipes through the attic, which in many cases aren’t insulated and are designed to allow for easy air flow to aid cooling in the summer. So you may need to drip an interior line or two so you don’t get an unexpected shower from a burst pipe above. Remember if you do drip something, that water will go somewhere – and probably freeze. So don’t end up like this …

busted pipes and water damage are 30% of insurance claims each year.

The bottom line is, as usual, use some common sense. We should’t have too many instances of icy roads, things should dry out before it freezes, but caution is still a good idea if you go to Christmas eve and morning services, and of course dress warmly.

Update: for those worried about the Atlanta area, here’s what the NWS duty forecaster said about 9:30am Tuesday morning about the snow/freezing precip potential …

 As far as the ATL metro is concerned, latest model guidance continues to remain pessimistic on wintry precip chances, but like mentioned, confidence is low on spatial coverage and accumulations. It boils down to the speed of FROPA and if there is any lingering moisture.

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