Weeks of dry weather look to come to an abrupt halt this weekend, as the remnants of Tropical Storm Nate move north out of the Gulf of Mexico and interact with a frontal boundary that is currently sliding across the nation's interior.
Scott County has not experienced measurable precipitation since Sept. 22 — and only five-one hundredths of an inch of rain since Sept. 20 and only 1.1 inches of rain since Sept. 6.
The result? Despite a very wet start to September and a wetter-than-usual summer overall, local streamflows have dropped below average for the first time in months. The Big South Fork River was running at just 52 cubic feet per second Thursday evening; Clear Fork was running at just 13 cfs. And the U.S. Drought Monitor has "abnormally dry" conditions — one step below an official drought — creeping into parts of East Tennessee.
But all that looks to change this weekend, as the tropical system could bring an entire month's worth of rain to the northern Cumberland Plateau in just a couple of days.
Keep in mind that when we saw "an entire month's worth of rain," we're speaking in October terms. October is the driest month of the year in this part of the country. In an average October, Oneida receives just a little more than three inches of rain.
Still, it looks like it could be quite wet, as the National Hurricane Center's current projected track for Nate brings the tropical depression almost directly over the region.
Forecast models relied on by meteorologists are coming into close alignment with the track of the system, which enhances confidence in the weekend's forecast. The National Weather Service's Morristown office has introduced 50 percent rain chances to the forecast from Saturday night into Tuesday, and this afternoon's area forecast discussion highlighted those rain chances.
In general, models are trending away from what were once serious rain totals for the region (the GFS computer model, which is perhaps the most accurate forecast model operated by the American government at this range, was once projecting as much as six inches of rain for the general Scott County area). The greatest rains will occur wherever the tropical remnants interact with the frontal boundary, and that looks like it will be slightly to our west, according to most models.
Still, a solid two to three inches of rain are not at all out of the question. And since the actual tropical depression won't knock on our door until Monday, it looks like it'll be a wet start to fall break for area students. Rain chances are considerable until Tuesday evening.
In this afternoon's forecast discussion, the NWS's Morristown office had this to say:
"The main path of this storm and the location of the frontal boundary will likely be where we see the highest precipitation amounts over the weekend and into next week. Most models are keeping the main band of the heaviest rain off to our west, but we can't rule out some heavy rain here if the track of the storm shifts or the front makes further eastward progress than we anticipated. Currently think we could see widespread precipitation amounts of 1-3 inches in our area, but it's possible some places could see up to 4 or 5 inches. This rain will fall over several days and with our recently (very) dry conditions we've experienced the rivers and lakes should be able to handle a good amount of water."
It may be Thursday before truly dry weather returns to the region.
Eye to the Sky is a weather blog by Independent Herald editor Ben Garrett. Garrett is a weather enthusiast who has long blogged about interesting weather on his personal website. He is not a professional forecaster or a meteorologist and information on this blog should not be considered a substitute for forecasts, advisories or other products from the National Weather Service.