Thursday, August 2, 2012

NWS concludes microburst produced minor wind damage in Olive Branch

On Monday night, July 30, shortly after 10pm, a small but powerful storm moved through the eastern side of Olive Branch, MS, just southeast of Memphis. As it passed over the automated sensors at Olive Branch Airport, a wind gust of 65 mph was recorded. Initially written off  (fully automated sensors are known to occasionally spew invalid readings), MemphisWeather.net nowcaster Kevin Terry decided to made a request for personal observations from people following MWN on social media in the Olive Branch area. And they came through!

Providing comments like "the wind was so strong and carrying so much grit in it it felt like pins and needles were sticking in me" and "I had to push my body against it to get back inside," it  became clear that the storm had produced more than ordinary gusts.  Probing further, the following report was received regarding the estimated wind speed: "I say close to 50mph...it was enough to blow over my overfull (sic) trash can." Then on Tuesday morning, an MWN follower said, "we lost 2 trees last night. Quite a few trees down in the neighborhood."

Reflectivity (precip - left) and velocity (wind - right) at 10:05pm on July 30, 2012.
A thunderstorm producing damaging wind is depicted.
Armed with reports of trees down and the other valuable information, we approached the NWS again about the 65 mph gust from the Olive Branch sensors. On re-examination of radar data from the NEXRAD in Millington, the NWS discovered that a microburst had descended from the storm on the east side of the town and happened to hit the official recording station for Olive Branch!  The 65 mph wind gust was determined to be accurate based on the reports and radar data and an official storm report was filed by the NWS.

MWN sincerely thanks all of you who provide feedback on what is happening in your area, particularly through our #mSpotter Twitter-spotting program.  Your reports are immediately transferred to the Memphis NWS office and help corroborate warnings, improving the quality of the information the NWS disseminates to the general public. This is just one example (another is the Germantown flooding from a few weeks ago) in which the NWS was able to verify the presence of severe weather through your first-hand accounts!  Keep it up and thanks so much!

----
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps,  now with StormWatch+!
Nowcasting services available on our Facebook page and Twitter feed.

Slight risk of severe storms this evening for parts of the Mid-South

The Storm Prediction Center, issuer of convective watch boxes and outlooks, has placed northeast AR and western TN under a Slight Risk for severe weather tonight.  The primary threat, besides dangerous lightning of course, will be damaging wind, with a slight chance of some hail as well. Tornadoes are not expected.

Convective outlook for the evening and overnight hours from SPC
Models do not all agree on the scenario for tonight, but a few indicate that storms will fire on a disturbance in Missouri left over from previous thunderstorms, then track south to southeast through the Mid-Mississippi River Valley towards the Mid-South.  If this is the case, storms should be weakening as they approach the metro and SPC tends to agree given that the southern end of the Slight Risk zone is at the TN/MS border.  Timing for any rain/storms will most likely be after dark (9-10 pm) through the very early hours of Friday should they occur.

Hi-resolution WRF model showing t'storms moving into the metro by 11pm tonight 
MWN will keep you updated with the latest info as it becomes available via our social media feeds listed below and will be nowcasting any storms that develop in the metro.

Now is a good time to make sure you have the MemphisWeather.net app for your smartphone and have activated StormWatch+, which will wake you up if severe weather threatens your location!  Download links and more information are also provided below.

----
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps,  now with StormWatch+!
Nowcasting services available on our Facebook page and Twitter feed.