Round of heavy rain and potential strong storms overnight

A welcome reprieve from wet weather is occurring this afternoon, which will continue into the evening hours.  Only a low chance of a shower is in the forecast through about midnight.  However, it will remain very warm and sticky.  This morning's rainfall was courtesy of a weak wave of low pressure moving along a very slow moving cold front draped across AR.  That wave has moved by, while another more potent low is forming further down the front.  It is triggering scattered strong storms from NE Texas into far SE Oklahoma and western and central AR.

At mid-afternoon, a line of thunderstorms is forming across AR that will move slowly east, arriving in the metro after midnight. Individual storms are moving northeast along the line. No organized rain is expected locally until this line arrives.

Severe weather risk

The Storm Prediction Center expects those storms to strengthen further as the afternoon and evening progress and could issue a Tornado Watch for much of the Slight Risk zone that extends from SW to NE across the state.  Storms are moving northeast along the line (called "training" of storms because the cells are like railroad cars, following one another along the track) while the line itself shifts slowly east pushed by the slow-moving cold front.  The Slight Risk zone extends into the western portions of the Memphis metro, west of I-55 in AR and far northwest MS and north of I-40 in west TN.

A Slight Risk area covers a good part of AR and the western metro. Damaging wind and an isolated tornado are possible in the slight risk area overnight.

What to expect locally

Within the Memphis metro, showers and thunderstorms will move in after midnight with the heaviest rain and any potential severe weather most likely between 2-6am Sunday.  The timing of the line does not typically portend a high threat of severe weather. But with temperatures still well into the 60s, dewpoints in the 60s, and a gusty south wind ahead of the line, this front, with its 40-degree temps behind it, will be strong enough to bring a threat of damaging wind and an isolated tornado in any storms that accompany it.

Perhaps the most widespread threat will be heavy and continuous rain that could drop an inch or more in just a couple of hours.  With saturated ground already, flash flooding could be an issue, thus a Flash Flood Watch remains in effect until noon Sunday.  Rain is likely to continue through the morning and early afternoon hours Sunday before tapering off by late afternoon.  Rainfall amounts could total 1.5"-2" locally by Sunday evening.  In addition, temperatures will plummet behind the front, likely falling 20 degrees within an hour or two of it's passage.  Most of the day Sunday will be spent in the 40s, or 30 degrees colder than today!

Expected rainfall amounts from 6pm Saturday through 6pm Sunday.  1.5-2" amounts are likely in the metro.

We'll have more tomorrow on the possibility of winter weather Sunday night or Monday as models struggle to determine whether precipitation occurs or not and how cold it will be.  In any case, it does not appear to be a significant issue at this point.

Prepare now with StormWatch+

With the threat of severe weather overnight, it will be a good idea to have a NOAA Weather Radio and StormWatch+, our pinpoint severe weather notification system within the MemphisWeather.net mobile app, at the ready.  StormWatch+ will wake you up if a severe thunderstorm or tornado warning is issued, but only if it is for YOUR GPS-determined location.

DO NOT count on tornado sirens to wake you up - they won't.  NOAA Weather Radios go off for entire counties, waking you even if you're in Millington and the warning is for Collierville (which is better than nothing at all).  But StormWatch+ is accurate enough to know if you are in the severe weather polygon determined by the National Weather Service.  If you're not, it'll let you sleep.  Download the app for iPhone or Android via the link below.

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