Here Comes Rain

Current Radar

Wednesday will be another muggy one. Dew points are expected to be a few degrees higher than yesterday. South winds are drawing in the warm, moist air from the Gulf, hence the cloud buildup.

The high temperature will climb to 86° with clouds increasing in the afternoon. Eventually an upper level trough will dig over us tonight, but before that rain chances will increase this afternoon as a surface low begins to scoot across Tennessee from the west.

Meanwhile, a line of showers and thunderstorms will be ahead of a weak cold front that will move across our area overnight into Thursday morning. Here is the NAM model after 3:00 PM:


Showers and thunderstorms will remain in the area late this evening:



The HRRR model is a little different:

The Storm Prediction Center has us in a general thunderstorm area; nothing severe is expected.

Screen Shot 2015-09-09 at 11.15.53 AM

Thursday’s high temperature will be 82° with a dew point in the upper 60s. That cold front from Wednesday will prove to have been fairly weak, unable to scour out the humid airmass.

Rain should continue at least through the early morning hours, and possibly beyond. Models suggest off/on rain will linger until just before sundown, clearing in time for evening outdoor activities. I wouldn’t bet on this forecast; it may clear sooner than that.

Friday we’ll be waiting for a Good Old American Fall Cold Front to arrive.

Unlike today’s approaching “cold” front, this one has muscle. It will do two things.

1.  Bring rain. The ETA on this rain is pretty fuzzy, but I like a late Friday night ETA, so think about whether you have rain gear for HS football. We’ll have a better handle on the ETA tomorrow night and Friday morning to determine if you’ll need it.

The rain should linger into Saturday, but “how long” is unclear. The Euro model is pushing a secondary wave of rain through Saturday evening, but the GFS doesn’t, so we’ll just be cool and wait for more data to arrive, hoping for a consensus opinion. The hope we had a few days ago of a glorious Saturday is fading.

NOTE: the Euro model thinks it’ll be raining in Knoxville for the Oklahoma game.

2.  Cool Us Off. This thing will scour away the humidity, dropping Sunday temps into the 50°s for early birds, 70°s in the afternoon. Dew points will crash through the 50°s into the 40°s, eliminating humidity from consideration.

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