A swirl of clouds from the ocean may bring us some rain Saturday … but it’s not Isaac (yet, at least)
The swirl of moisture shown earlier this evening on the satellite photo at right may bring a rather rainy day to parts of central and eastern Virginia on Saturday. And it may spin enough moisture even into western Virginia for enhanced showers, or at least, more clouds and cooler high temperatures — not that highs have been hot at all lately, but they may remain in the 70s on Saturday with clouds and showers. This swirl of clouds is a low-pressure system that may drift inland a bit this weekend. At least one meteorologist has noted it’s associated with the mid-level circulation of the barely-known Tropical Storm Helene that came inland in Mexico several days ago. The atmospheric spin it contains was significant enough for a supercell thunderstorm to develop tight enough rotation that a tornado warning was issued for Ocracoke Island in the Outer Banks on this Friday night. We experienced some effects of it Friday, as its rotation spun showers to the southwest, including one that gave a quick downpour to parts of Roanoke between 2 and 3 p.m. While this system is not a wholly tropical entity, its possible origin and the fact that it is moving westward indicates we have moved into a tropically influenced weather pattern.
Tropical Storm Isaac is nearing hurricane strength just south of Haiti late on this Friday evening. It is crossing a thin peninsula of southwestern Hispaniola, not the densely mountainous middle, that probably won’t sap its strength much, but then it is projected to move diagonally northwestward across Cuba. It may have a hard time getting anything stronger than minimal hurricane strength until, possibly, it blows into the very warm, open waters of the Gulf of Mexico late Sunday. Most forecast guidance is pointing to a Florida Panhandle/south Alabama landfall by Tuesday or so. Just as there remains some uncertainty about its track over the Gulf, its path and effects once it moves inland are a little fuzzy … but this Climate Prediction Center 6-to-10-day precipitation map certainly shows a potential wet bullseye over the southern Appalachians and Mid-Atlantic regions. Some forecast guidance turns it sharply northeastward once inland, keeping most of the rain south and east of our part of Virginia, while some of it carries it farther inland to the northwest, and brings Isaac’s remnant low toward us a couple of days later. There are a few more days to sort that out. Southwest Virginia usually — though not always — gets a pretty good soaking when a tropical system comes into the Florida Panhandle.