Friday, January 7, 2011

Update on snow potential for this weekend

As of this 12:30pm Friday, conditions are still coming together for a potential winter storm across the Mid-South on Sunday night. The images above provide just 3 of many solutions we weather guys and gals are looking at regarding the storm. The top two images show snowfall totals from U.S.-based computer models, while the bottom image is the National Weather Service forecast for expected snow amounts.

The computer models are re-run every 6 hours and solutions change every time they are run, but they are beginning to hone in on the big picture, which includes surface low pressure moving along the Gulf Coast and an upper-level low moving across north Mississippi.

Lingering questions
The remaining questions seem to revolve around how much moisture is available for the upper-level low to work with (which would greatly affect snow totals) and how strong the dynamics/lift are in our area as well as to the south, as well as the exact track of the upper low. Stronger dynamics in our area would result in heavier snowfall, while stronger dynamics to the south could limit the ability of the Gulf moisture to move over the metro area, thereby limiting our snow totals. (Thunderstorms along the Gulf coast could rob areas to the north of moisture.)

As far as timing, light snow showers could begin moving in from the south and west Sunday afternoon but accumulating snow should hold off until after dark Sunday evening. Most of that snow will be done by rush-hour Monday morning. I expect to see Winter Storm Watches posted for part of the area later this afternoon.

MWN Forecast
Currently, we expect snow totals just slightly below what the NWS is forecasting and fairly close to what the 6am NAM had this morning (see the second image above). That is, a range of 1-3" over the northern metro (Tipton County included), 2-4" over the heart of the Bluff City and Crittenden and Fayette Counties, and 3-6" south of the TN/MS state line. It appears the heaviest swath of snow will end up somewhere over north MS, likely south of the immediate metro area. More updates to follow...

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