Don’t get used to the mild December weather.  The cold air returns late tonight, and temperatures will start in the low 40s on Tuesday and fall during the day.  There will only be a slight chance for a shower tonight through early tomorrow as the cold front pushes through.  Lows Tuesday night will drop to the mid 20s.  Back to reality!

With a low of only 50 degrees Monday morning and a high in the low to mid 60s, the work week will be starting off on the mild side.  But it will only be temporary.   Monday night into Tuesday morning we will have a slight chance for a few showers with another cold front which will bring us back to reality on Tuesday.  Tuesday will start out in the mid 40s and temps will fall as the day goes on.  By Wednesday morning we will be in the mid 20s with a high only near 40 on Wednesday.

The overcast skies will persist tonight with mist and fog in the air reducing visibilities late tonight and Monday morning.  Temps will remain mild, with lows in the upper 40s and highs on Monday in the low 60s despite mostly cloudy skies.  But don’t get too used to the mild temperatures.

On Monday night into Tuesday morning we expect a few showers as another cold front pushes our way.  On Tuesday, temps will start out in the mid 40s and fall as the day wears on.

After a wet Saturday night and Sunday morning, the rain will be moving out as the morning wears on.  The clouds may hang in there on Sunday, but there should be some sunshine peaking between by afternoon helping temps to reach the low 50s.

Sunday night will become partly cloudy with patchy fog and lows near 40 Monday morning.  Monday, we should crack the 60s before showers and a few t’storms arrive Monday P.M. followed by more cold air Tuesday through Thursday.

You can see the rain pushing in on Stormtracker above, and it will be around tonight through Sunday morning.  Temperatures will temporarily fall into the upper 30s in the rain due to what we call “evaporational cooling”  in the rain (I’ll explain that below, and then rise back into the low 40s by daybreak.

On Sunday, morning showers will give way to mostly cloudy skies with some peaks of sun during the afternoon and temps warming to the low 50s for highs.

Evaporational cooling can occur when rain falls into very dry air (our dew point in in the upper teens, and that’s pretty dry).  Some of that rain evaporates, and evaporation is a cooling process.  That’s why when you get out of a swimming pool you feel cool as the evaporating water draws heat out of your skin.  In the same way, the evaporating rain pulls heat out of the air.

If you look at Stormtracker, as of 1:15pm the rain was just approaching south Middle Tennessee from Mississippi and Alabama.  This allowed the Mt. Juliet Christmas Parade to go on rain free.  Sparta and Hartsville have parades at 2pm.  It looks like they might just make it with the rain coming in late this afternoon towards sunset.  Highs today will  be in the mid to upper 40s, with a low tonight near 40.

Once the rain arrives, it will stay around tongiht through Sunday morning.  We should see some sunshine Sunday afternoon with highs in the low 50s!

It still looks like it will be afternoon before the rain pushes into Nashville, though it could make its way into our south and southwest counties during the late morning hours where it could have some sleet mixed in before changing to all rain as temperatures rise into the 40s.  The rain should last through Saturday night and Sunday morning with partly cloudy skies Sunday afternoon with highs in the low 50s.

After a cool night with temps in the mid 20s for lows, it looks like the rain will be reaching Nashville during the afternoon hours of Saturday.  It could be in our south and southwest counties during the late morning hours.  There could be a little sleet mixing in the leading edge of the precipitation, but it is going to be mostly rain with temps in the mid 40s during the afternoon. 

The rain will hang around Saturday night through Sunday morning, with clearing skies Sunday afternoon.  Afternoon highs on Sunday should reach the low 50s.