RE: FRIDAY’s ARCTIC COLD FRONT and *POSSIBLE * SNOW SQUALLS in SOUTHERN MID ATLANTIC
DT -WxRisk is a busy as a T-REX in late cretaceous period attacking a herd of Hadrosaur. After this update I will make a post about the Midwest AND watching something DEC 27 (or you normal mundane ordinary humans that don’t understand the reference ….ask your 7 or 10 year who loves dinosaurs).
In the large scale of things nothing really has changed. There is going to be a Blizzard across the heart of the Midwest which will begin early Thursday morning and continue right to until Friday evening. For the Middle Atlantic region, this event will primarily be a rain event as the intense LOW pressure area moves from southeast Missouri into Indiana and Michigan. This will pull up strong south winds and bring in mild air as far north as southern Maine and central New York. However, at the beginning of the event there will be an Inverted surface Trough on Thursday morning along the Carolina coast. This will cause rain to break out in North Carolina which will spread rapidly into Virginia and Maryland and Delaware on Thursday. But with cold air dammed up against the mountains in the Shenandoah Valley, eastern third of West Virginia, and western Maryland temperatures will be cold enough to support a period of Sleet.
The recent spell of cold temperatures during the overnight hours have allowed ground temperatures to drop several degrees. At the beginning of the event Thursday morning readings will be around 30 degrees so there will be some icing problems for several hours on Thursday. In southwest Virginia — EAST of Interstate 77 including areas like Roanoke, Blacksburg, Hillsville etc AND in southeast 25% of West Virginia, the sleet will begin around 4 am on Thursday and continue until about noon.
In the central portions of the Shenandoah Valley and the eastern portions of West Virginia the sleet will begin around 8am on Thursday and reach into western Maryland Winchester Martinsburg Hagerstown by 11 am. It looks like the interval of sleet will last anywhere from 6 to 9 hours which means that in the central and northern portions of the Shenandoah Valley, western Maryland, and the eastern third of West Virginia the sleet will continue until about 2 or 3 pm before it changes to rain.
Temperatures will rise Thursday night into Friday morning across all portions of the Mid-Atlantic region. East of the mountains readings in pre-dawn will reach into the low 50s and possibly 60 degrees near the coast before the cold front hits.
Next, we have to deal with the Arctic cold front on Friday morning. These images show the morning GFS model which is the most aggressive of all the models showing the rain changing to snow Friday morning for a couple of hours when the arctic cold front hits. Most of the other data does NOT show this much snow in the Middle Atlantic region when they cold front arrives. So this amount of snow that the GFS model is showing — see images- is probably over done but it is not out of the question.
The energy with this Arctic cold front is Extreme and at the top of the charts so it could produce a Squall line of heavy snow lasting 1 hr that could whiten the ground up to 1 inch especially in the Shenandoah Valley, southwest Virginia, into Central Maryland to the north and west of DC and Baltimore.
In the Eastern third of West Virginia several inches of snow are quite likely with the arctic cold front as it moves through the mountains plus additional snow squalls on Friday afternoon and again on Saturday from the Northwest Arctic winds coming in from the Eastern portions of the Great Lakes.
The front will cause temperatures to collapse 20 or 30 degrees in a matter of two or three hours. These images showed the progression of the cold front Friday morning. This means that the max temperature on Friday will occur either before Dawn or before noon depending on the location. The data shows winds with gusts up to 40 mph when arctic cold front hits and for several hours behind it. Again, I need to emphasize that there is a possibility that there could be a snow squall line with the article fun as it sweeps through the Middle Atlantic region even in the areas east of the mountains across the central and Eastern portions of portions of North Carolina, Virginia, Maryland, and Delaware.
Christmas Eve and Christmas day will be the coldest Christmas days in many years across the entire eastern half of the country including all of the Mid-Atlantic region. Min temperatures on the morning of December 24th and 25 in the mountains of Pennsylvania, the western half of Maryland, Shenandoah Valley, southwest Virginia, northwest mountains of North Carolina, eastern Kentucky, and the entire state of West Virginia will be close to 0 or Sub-Zero in many locations. East of the mountains min temperatures will be in the low teens except along the coast where readings will be closer to 20 degrees.