Looks like we have a chance for some winter weather tonight across the northern tier of counties in the mountains, and especially toward the NE corner of the state, where many will possibly see some significant icing. Fortunately, temps will rise above freezing Sunday, so it will be a short lived event. First, let's look at the Winter Weather Advisory. By definition, a Winter Weather Advisory is "issued up to 36 hours before an event for an 80% or greater chance of a winter precipitation event "snow, freezing rain/drizzle, sleet or blowing snow) which causes inconveniences but does not meet warning criteria." Here is the advisory: WSWFFC URGENT - WINTER WEATHER MESSAGE National Weather Service Peachtree City GA 334 AM EST Sat Feb 3 2018 ...Winter Weather Expected for portions of Northeast Georgia Tonight and Sunday Morning... .An arctic airmass currently in place will begin to be overrun by mid and upper level moisture during the evening Saturday and the overnight hours Sunday morning. As a result mixed precipitation is expected to occur across portions of North and Northeast Georgia. Some sleet will be possible at the onset of precipitation for areas outside the advisory area including the Atlanta Metro however no impacts are expected. As precipitation increases in intensity after midnight... it is expected to transition over to all freezing rain within the advisory area and accumulate. Temperatures are expected to remain at or below freezing through the late morning hours Sunday before warming above freezing in the advisory area. Fannin-Gilmer-Union-Towns-Pickens-Dawson-Lumpkin-White-Hall-Banks- Including the cities of Dahlonega, Cleveland, and Gainesville 334 AM EST Sat Feb 3 2018 ...WINTER WEATHER ADVISORY IN EFFECT FROM 1 AM TO 10 AM EST SUNDAY... * WHAT... Mixed precipitation expected. Total snow accumulations of up to one half inch and ice accumulations of around one tenth are expected within the advisory area. * WHERE... Portions of north central and northeast Georgia. * WHEN... From 1 AM to 10 AM EST Sunday. * ADDITIONAL DETAILS... The ice will result in difficult travel conditions... especially on bridges and overpasses. Be prepared for reduced visibilities at times. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Winter Weather Advisory means that periods of snow, sleet or freezing rain will cause travel difficulties. Be prepared for slippery roads and limited visibilities, and use caution while driving. Also for Georgia and issued by the Greenville/Spartanburg NWS office: -------------------------------------- Rabun-Habersham-Stephens-Cleveland-Greater Caldwell-Greater Burke- Eastern McDowell-Greater Rutherford-Eastern Polk-Oconee Mountains- Pickens Mountains-Greenville Mountains-Greater Oconee- Greater Pickens-Greater Greenville-Spartanburg-Cherokee-Anderson- Including the cities of Clayton, Pine Mountain, Mountain City, Cornelia, Demorest, Clarkesville, Hollywood, Boydville, Toccoa, Shelby, Kings Mountain, Kings Creek, Lenoir, Sawmills, Granite Falls, Morganton, Pleasant Grove, Valdese, Marion, Nebo, Dysartsville, Fero, Glenwood, Forest City, Rutherfordton, Spindale, Tryon, Columbus, Mill Spring, Mountain Rest, Walhalla, Westminster, Pumpkintown, Tigerville, Gowensville, Cleveland, Seneca, Oakway, Easley, Dacusville, Clemson, Greenville, Taylors, Greer, Mauldin, Fork Shoals, Simpsonville, Berea, Spartanburg, Gaffney, and Anderson 328 AM EST Sat Feb 3 2018 ...WINTER WEATHER ADVISORY IN EFFECT FROM 1 AM TO 10 AM EST SUNDAY... * WHAT...Mixed precipitation expected. Total snow accumulations of up to one inch and ice accumulations of around one tenth are expected. * WHERE...Portions of upstate South Carolina, northeast Georgia, and the northwest piedmont and foothills of western North Carolina. * WHEN...From 1 AM to 10 AM EST Sunday. * ADDITIONAL DETAILS...The ice will result in difficult travel conditions. Be prepared for reduced visibilities at times. PRECAUTIONARY/PREPAREDNESS ACTIONS... Cold air moving in today will set NE GA up for some potential ice early Sunday. Areas north of I20 could see some sleet mixing in as the precip moves in late Saturday before changing to all rain. NE GA may see some accumulations of freezing rain on trees and bridges/overpasses by dawn Sunday. Impacts would be mostly confined to travel with all of it gone by afternoon as temperatures warm above freezing. It is always a good idea to read the AFD's or area forecast discussions to get a good feel for what the National Weather Service is thinking behind the forecast. Here is an excerpt from the latest AFD from 3:15am Saturday AM. ----------------------------------------- All eyes will be to the west this evening as modest but large area of energy moves out of the plains and into the Mississippi Valley. Quick movement of this system will allow for a rapid transition from mid level clouds to low clouds and developing precipitation by 03Z to 06Z. Almost invariably in these type of setups, we get more sleet than we think at the onset and expect to hear of reports even in the metro, although no travel issues are anticipated with temps above freezing. A different story for NE GA where insitu wedge situation looks to develop. Have gone with a blend of the coldest guidance including the regional Canadian to yield onset temps in the upper 20s to around 30. Top down method gives me everything including the kitchen sink for precip type... rain... freezing rain.... sleet... and even a little snow at the highest elevations. Transitions to all FZRA and RA though and expect those to be the primary hazards with this event. Even a glaze of ice satisfies advisory for the local area and with a possible tenth of an inch, will hoist one for portions of NE GA from 06Z-15Z. Will be a very slow warmup and will stick close to cold guidance again with only mid 30s for highs within the wedge Sunday. Otherwise, QPF looks manageable at under and inch for all locales. Here are two probability maps from the Weather Prediction Center (WPC) showing the probability of freezing rain >=0.01" (left) and >=0.10" (right) Here's a sequence of images from the NAM 3km showing how it sees things playing out. It's QPF amounts are on the high side but you can get a feel for how this model sees the placement. Click to enlarge the images.
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