JASPER, Tenn. — We have a very challenging forecast ahead for the Sequatchie Valley. Looking at the latest forecast guidance, not much has really changed in the overall thinking concerning our snow potential for Thursday.
A low pressure system will develop later tonight or early Thursday along the same frontal boundary that has brought flooding rains to the area for the past several days. That front will be nudged eastward as an upper level “trof” progrades. A strong shortwave embedded in the flow will rotating into MS/AL tomorrow morning/afternoon and take on a negative tilt and finally closes off.
Forecast radar simulations from NAM/RAP indicate a heavy band of snow as far south of southern Mississippi developing tomorrow morning on the backside of the low. This band will quickly slide eastward with time and impact locations further south into Alabama. However, this will need to be watched as our area in located in the synoptically favored regions for snow.
The only issue for you snow lovers will be temperatures (thermal profile). As the closed low passes to the south, dynamic cooling will be maximized over those locations. A combination of cold air advection and minimal dynamic cooling may help change us over around lunch time; however, I do expect a window of rain and snow mix as thermals will gradually cool.
One concern I have right now is precipitation intensity. If a pocket of higher precip rates occur, dynamic cooling will increase changing us over to all snow and those heavy precip rates will mean more snow. At this time it looks like the heaviest precipitation will remain south with the upper level low. Precipitation will come to an end around 6pm Thursday.
Given relatively warm ground temperatures it will take a high density snow to accumulate. I’m not expecting major travel problem initially; however, as temperatures cool overnight I do expect black ice to form on most roadways so use caution driving overnight and early Friday. **It should be noted that there still remain a bit of uncertainty given uncertainty relating to temperatures. We’ll have a late night here in the weather office to analyze new information that comes in around midnight.
Forecast for Marion County:
Thursday: Rainy and cool. Rain will mix with and change over to all snow by afternoon. Snow accumulations will range from a dusting to maybe up to an inch with slightly more possible in the higher elevations. High temperatures will be around 38 early and dropping through the day.
Thursday Night: Precipitation ending during the evening with decreasing clouds. Low temperatures will be around 28. Watch for black ice that may form if you plan to drive.
Friday: Becoming Mostly Sunny with highs in the mid 40’s. Again, there will be a threat for black ice early Friday.
Updated: 5:38 CST on Jan 16, 2013
Staff Meteorologist: Robert Frye
Robert Frye is a Jasper, TN native and Marion County High School graduate. Robert holds a degree in Meteorology from the University of South Alabama in Mobile and is currently a graduate student in Applied Meteorology at Mississippi State University. Frye works for a NOAA contractor as an ice/snow analyst in Washington, D.C., and is Chief Staff Meteorologist for MarionCountyMessenger.com — the only daily local news and information website in the the Tri-State area to employee an actual qualified meteorologist for exclusive weather forecasting and analysis.