UPDATE 11:10 AM, 10/1: Naming winter storms? Really? Discussion as 2 days of dreary weather begins to clear out
UPDATE 11:10 AM: Comments from 10:38 a.m. (#39) on discuss The Weather Channel’s new plan to name winter storms, similar to hurricanes, a convention that will NOT be recognized or employed by Weather Journal. END UPDATE
UPDATE 10 PM, 1/1: The high temperature barely made 60 at Roanoke and only 55 at Blacksburg on a damp Monday, the coolest highs since April. Heavy showers and some storms will move through Southwest Virginia overnight and Tuesday as a low tracks to our west, dragging first a warm front through and then a “cold” front that won’t live up to its name. (Because it will bring in dry air and southwest winds that will cause as spike of warmth during the day on Wednesday). Rain amounts near an inch may occur through Tuesday evening with locally heavier amounts. The greatest atmospheric shear will be near the low in the Ohio Valley, while the greatest instability will be in somewhat warmer air to our east and southeast, so it doesn’t appear likely the two will intersect enough for much of a severe storm threat on Tuesday in Southwest Virginia. A few strong storms are possible, though, especially when, where and if there are any breaks in the clouds allowing warming. END UPDATE
UPDATE 12:15 PM, 10/1: The Doppler upgrade to dual polarity has been delayed until Wednesday, so NWS-Blacksburg radar will remain operational through rain and possible storms today and Tuesday. END UPDATE
Remember that the National Weather Service-Blacksburg’s Doppler radar site in Floyd County will be taken offline Monday for its scheduled upgrade to dual polarity technology. The Radar / Future Cast on this Web site uses data from that radar site, but neighboring radar sites will provide enough information to give at least some idea of rainfall coverage on Monday and Tuesday, though it may not perfectly reflect what is going on.
A low pressure system moving along the Gulf of Mexico, and then northeast along or just west of the spine of the Appalachians, will bring lots of Gulf moisture into our region Monday and Tuesday. The first round of it is likely to arrive Monday morning in the form of “overrunning” rainfall, as a broad area of light to moderate rain develops when moisture moves on top of cooler, drier air being forced in from the northeast. This damp “wedge” effect will keep temperatures cool, with highs possibly not topping 60 in much of Southwest Virginia, and no higher than the mid 60s anywhere. We may see a break in the rain as the overrunning area lifts northward later Monday, but showers and possibly some thunderstorms will develop as the low moves northeast and drags first a warm front northward and then a cold front eastward. Southeast winds pulling into the low will also wring out moisture as it is lifted up the mountain ridges. Tuesday is likely to be a more showery, warmer day, with maybe even a few breaks in the clouds, as we move into the “warm sector” of the storm system. There is at least some chance of strong or severe storms as the atmospheric shear (winds changing direction and/or speed with height) will be conducive, though instability will be marginal. All in all, most spots in western Virginia can expect something close to an inch of rain the next couple of days, with perhaps some heavier rain along eastern slopes of ridges and where any stronger storms or heavy showers may develop or move over the same areas Tuesday.
The rest of the week looks mostly dry with temperatures near to slightly above normal — 70s highs and upper 40s to mid 50s lows, mostly. Beyond this week, colder weather appears likely to set in.