Tuesday PM update - storm chances through Wednesday

UPDATED - 6:50pm CDT:
This evening's threat is waning as storms are having trouble departing MO and are weakening as they do, thanks to a cap of stable air they are attempting to sink south into. Our overnight chance of rain is now just 20%. The rest of the blog regarding tomorrow is still on track, including weakening of morning storms before they get here.

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ORIGINAL POST - 3:10pm:
A warm and muggy day today has resulted in cloud cover over the area most of today, a sign that humidity is increasing as we head into a stormy pattern. The regional radar loop (shown below - always current) as of mid-afternoon shows a complex of storms extending from the St. Louis area west across MO.

Current regional radar loop. As of mid-afternoon storms are just coming into the picture in central MO as they drop southeast towards the Mid-South.

This complex will continue move southeast and is our first "fly in the ointment." As it moves south, it will encounter very moist air that is also unstable and will remain that way well after dark. Most models think it will either fall apart or move by to our northeast after dark. However, one of the more reliable short-term high-res models says "not so fast." If it's right, we could see some lightning and thunder between 10pm-2am. Severe weather is not expected locally, but a few strong storms are possible as the line moves into northwest TN early in the evening.

Once that passes, we turn our eyes to the west, where an outbreak of severe storms will be ongoing in the eastern and southern Plains. A line of storms is expected to cross AR by the wee hours Wednesday and will likely affect the metro after rush hour Wednesday morning. Once again, I expect we'll see a weakening line that will be in a state somewhere between scattered showers and a broken line of non-severe storms, depending on which model you believe. Either way, no morning severe weather is expected at this point.

HRRR (high-res model) "simulated radar" though 3am shows the MO storm complex grazing the metro and the Wednesday morning system approaching from the west. Graphic courtesy WxBell. 

However, the morning system will have a direct impact on what happens the rest of the day. The best bet is that we'll see a few peeks of sun by mid-day and the atmosphere will "re-energize" as the day goes on and as a cold front approaches from the west. The entire Mid-South is in a Slight Risk (category 2 of 5) for the potential for strong to severe storms to develop and move through the metro.

The primary risks will be large hail and damaging wind, though a tornado is possible. I also expect we'll see some refinement to the severe weather outlook tomorrow once the effects of morning rain on the overall state of the atmosphere are better understood. An Enhanced Risk (category 3/5) outlook is entirely possible somewhere in the Mid-South. The most likely timing for PM strong storms will be from mid-afternoon through about midnight, with additional refinement also expected as we head into tomorrow. If you have evening activities outdoors, we strongly recommend a plan B and to stay weather aware. (Yes, I know it has rained for about 1,512 Wednesdays in a row...)

After Wednesday, Thursday looks warm and dry with storms possibly returning by Friday evening and lasting off and on throughout the weekend.

Below are some tips to review prior to our severe weather threat - know them and share them! In addition, we highly recommend you have multiple ways of receiving severe weather warnings, no matter if you are at work, home, or asleep. Pros and cons of multiple ways are shown below as well.  One of those ways, if you have a smartphone, is to have StormWatch+ severe weather notifications set up via the MemphisWeather.net mobile app. Links to more information and downloads are at the bottom of this post. Stay tuned to our social media accounts also listed below for the latest information!

Stay safe!

Erik Proseus
MWN Meteorologist

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