Nashville, Tennessee

New AVIATION

• Low rain chances in our southwest counties for trick-or-treat. Medium to high rain chances spread area-wide late tonight into Sunday.
• A high chance for soaking rainfall middle of next week.

The rest of the day will feature a departing high pressure pattern. It will be cloudy and mild across the Mid State with an increasing southeast breeze, maybe as high as 20 mph at times. Temperatures will remain in the 60s to lower 70s through candy time. We continue to watch an approaching trough and swatch of deep moisture over the Plains and Lower Ms Valley that will move into our area late tonight through Sunday. Moisture streaming out ahead of this system may produce a few very light raindrops in our southwest counties during trick-or-treat, but we continue to expect most of the area to stay rain-free this evening. A lot of the atmosphere column is still quite dry, so radar returns will be showing up well before any measurable rainfall begins.

Showers will overspread the Mid State late tonight, and especially Sunday morning. Forecast soundings depict a saturated profile through the majority of the column with no instability. This means mostly light to moderate showers with the highest pops Sunday morning through midday. The higher rainfall totals will occur west of I-65, but even these areas will not experience any "drought busting" amounts. Most areas will collect less than 1 inch, and most areas east of I-65 will be lucky to receive one half inch. The lack of instability means we are not worried about strong or severe storms, but a rumble of thunder cannot be ruled out.

Passage of the upper level trough will allow showers to taper off late Sunday afternoon into Sunday night. The low level pattern will stay the same with a mild southeast breeze.

Mild and dry conditions are expected Monday into early Tuesday as we look upstream for the next active system. That system will be a much more potent low pressure center that will bring soaking rainfall across the area by midweek. Deep moisture, gusty breezes, and strong lift will develop by Tuesday evening, bringing a high chance for showers across the area Tuesday evening through Wednesday. Models are varied with the exact details of this storm system, but models are confident we will have potential for heavy showers at times, especially Wednesday. The system looks quite dynamic, so some storms should be expected. However, the shear and instability parameters do not appear to line up for much of a severe storm risk. It is something we will have to keep an eye on.

While this weekend`s rain event looks like a potential under-achiever, the midweek storm system could be an over-achiever. Widespread 1 to 2 inch rainfall totals are expected, but some spots could pick up more than 2 inches. That would certainly not end the drought, but it would pause the trend for a while.

Some showers may linger Thursday and perhaps early Friday as trailing troughiness impacts the region. It looks like dry and seasonable air will come in later Friday, setting us up for a nice fall weekend.

Mid and high clouds have spread across Middle Tennessee in advance of an approaching shortwave. Light radar echoes are showing up over West Tennessee, but it will be some time before the low-levels moisten up enough for precipitation to start impacting the terminals here in the mid state. Expect light rain to begin developing during the overnight period and spreading eastward during the day Sunday, along with MVFR ceilings.

Nashville      53  63  53  72 /  70  90  30  10
Clarksville    53  63  53  73 /  70  90  30  10
Crossville     48  60  47  68 /  10  50  30  10
Columbia       52  64  52  73 /  90  90  20  10
Cookeville     53  62  52  70 /  20  60  20  10
Jamestown      51  62  50  70 /  10  50  30   0
Lawrenceburg   51  62  52  72 /  90  90  20  10
Murfreesboro   53  64  52  74 /  60  80  20  10
Waverly        53  62  54  71 /  90  90  30  10

None.