Ice threat leads to winter storm watchPosted Jan30, 2008 at 03:28 PMUPDATED AT 5:30 PM The battle between the irresistible force -- warm, moist Gulf of Mexico air being pulled northward by a strong low pressure system to our west -- and the immovable object -- cold, dry air pushed southward by a high pressure system in southeast Canada -- will put Southwest Virginia in an atmospheric tussle that could lead to widespread freezing rain Thursday night and early Friday. As a result, the National Weather Service has issued a winter storm watch that includes the Roanoke and New River valleys and most counties along the Blue Ridge and points northwest. The irresistible force will win, and temperatures will rise above freezing Friday to melt the ice. It all depends on how much rain falls before temperatures can get above freezing how big a deal this will be. 
Latest HPC map puts moderate ice risk threat, in green, farther west than earlier maps The obvious question that arises for the immediate Roanoke area is whether the city can again pull out a 33-degree escape as we did on Dec. 16 and last Feb. 13. It is certainly possible that will end up happening, but three factors argue against it: (1) a greater degree of evaporational cooling, with moisture moving into cold, dry air at the onset, (2) more well-established cold air damming against the eastern slopes of the mountains than in those previous episodes, and (3) the overnight arrival of the precipitation. We could well see some sleet or even very brief snow on the front edge of the precipitation, which would help cool things that much more. It seems likely to me from here that we will see some ice even on the floor of the Roanoke Valley on Friday morning, but the low to the west will be so strong it will easily pull warm air northward to push things above freezing by mid-morning Friday. In an unusal twist ... the Roanoke Valley could actually end up being one of the last to warm significantly as milder air is pulled in at a higher elevation above the valley first. Would not be surprised if we struggled through the 30s during the day on Friday while some higher elevation areas to our south soared into the 50s. |
About this blog
Kevin Myatt works on the copy desk for The Roanoke Times and is its principal weather geek, writing a weekly weather column and advising the newsroom on weather topics. He helps guide students on a storm chasing trip to the central U.S. each May and was an editor for "Hurricanes and the Middle Atlantic States." .....Advertisement.....
|
...Advertisement...
...Advertisement...
No comments yet