Wednesday, March 29, 2017

Round 3: More severe storms possible on Thursday

** 9:00PM UPDATE **

Slight adjustments to the forecast, mainly to speed up timing of the arrival of rain and storms overnight by a couple hours. We are still in an Enhanced Risk (category 3/5) of severe weather overnight with the primary risk being damaging wind. An isolated tornado or hail storm can't be ruled out. Make sure you have ways to get severe weather warnings when sleeping - we recommend StormWatch+ in the app.

For tomorrow, the cold front arrives in the metro between noon-2pm. A few storms are still possible during that timeframe though more widespread, and stronger, storms will occur to our east during the afternoon. An Enhanced Risk of severe weather is also forecast for tomorrow. That could change overnight (we expect a downward trend if it changes at all). Behind the front, no additional rain or storms are expected. Have tickets to the Redbirds/Cardinals exhibition? Leave the umbrella at home and go enjoy it!

An active weather period continues on Thursday with the next in a gravy train of low pressure systems that have affected our region over the past week or so. After this one, we'll get a break for a few days again, leading to a nice spring weekend (or most of one). But on to pressing matters!

Two rounds of weather are expected to affect the metro on Thursday as a strong low pressure system slowly moves out of the eastern central Plains into Missouri and a cold front slices across the Mid-South.

Threat #1

Storms will fire up and move east across Arkansas this evening, reaching the metro in the wee hours Thursday morning. This batch of storms is expected to affect the metro sometime between 2am-9am. The wide window is due to multiple short-term models indicating different scenarios playing out and overall low confidence in any of them right now. The best chance of rain and storms is likely between about 3-6am though.  This initial batch brings the primary threat of damaging wind, though some hail and an isolated tornado are possible depending on how the system evolves.

The high-resolution NAM 3km model simulated radar at 1am, 4am, and 7am shows the possibility of a couple of broken lines of storms moving through the area. Short-term models still have different ideas on how the early morning hours will play out exactly, thus there is low confidence in who will see what and when. (Pivotal Weather - click here if loop doesn't animate
A morning lull in activity will allow the atmosphere to renew the destabilization process. Any sunshine in this period would be unwelcome. Warming near the ground is fuel for storms that we call instability. The more there is, the more likely subsequent storms will be stronger.

Threat #2

By late morning or lunchtime, we'll likely start to see new cells form over or just barely west of the metro. I expect that they will quickly strengthen, but that will depend on just how much "renewal" the the atmosphere entertains before then. Between 12-3pm, a few storms will move across the metro and could be severe. I say "a few" because this isn't going to be another big line that affects everybody. You may not see any PM storms. "A few" is also code for "possible supercells." Supercells can produce large hail, damaging wind, and and tornadoes.

The high-resolution NAM 3km model simulated radar at 10am, 1pm, and 4pm shows scattered strong storms firing up just west of the river and becoming more of a line of storms by the time they are east of the metro. Most models agree much better on this scenario than the morning with slight variations in timing and storm strength. (Pivotal Weather - click here if loop doesn't animate)
I believe the highest threat of severe supercells is east of the metro as the storms continue to develop moving across west TN and north MS. However, with enough instability and the right timing, a few storms could explode over the metro and produce hail, high wind, or a tornado. The good news is that threat quickly shifts east of the metro by about 2-3pm and the severe weather threat ends for the day. That's good news for most school dismissal times, rush hour travel, and of course the Memphis Redbirds exhibition against the St. Louis Cardinals tomorrow evening. The evening hours should be pretty pleasant weather-wise!


Be Prepared, Not Scared

As always, please prepare yourself, your families, and anyone else you are responsible for for the possibility of severe weather overnight and early tomorrow afternoon. Check back for updates to the forecast as timing COULD still change, which could necessitate changing how you prepare and respond. We highly recommend downloading the mobile app and adding and setting up StormWatch+ in the app, which will allow you to receive push notifications as soon as watches or warnings are issued for your SPECIFIC location(s) of interest. You also should have another method or two of receiving severe weather info, such as NOAA Weather Radio and radio/TV.

I'm planning a live update on Facebook tonight about 8pm. Tune in via the link to our Facebook page below and have your questions ready! Also check our social media links for the absolute latest information throughout the next 24 hours or so.

Erik Proseus
MWN Meteorologist

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1 comment:

Anonymous said...

"Watch out for severe weather including possibly a strong tornado or two"... or the lack of so much as a drop of rain. Wish I had as much leeway in my job performance.