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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Follow MWN on Facebook, Twitter, and Google+ .
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!

MWN is a NOAA Weather Ready Nation Ambassador

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Time for the A/C, but how about our storm chances this week?

A beautiful spring weekend is about in the books; hope you got a chance to get out and enjoy it! A little warmth crept into the area as high pressure shifted to our east, allowing warm southerly air to move in. With almost no cloud cover, highs reached 80°+ each day this weekend, but humidity levels were still comfortable and morning lows were very pleasant (in the 50s).

The surface map for Sunday night shows high pressure on the east coast bringing warm, southerly flow into the Mid-South, while a storm system organizes in the Plains.

Monday and Tuesday

As we head into the last week of April and towards the first weekend of Memphis in May, the warming trend will continue with a few chances of thunderstorms from the middle of the week into next weekend. Starting early in the week, dry weather continues as the focus for strong to severe thunderstorm activity focuses on the central and southern Plains. With increasing humidity, expect cloud cover to also be more prevalent than the weekend, though partly cloudy will suffice for Monday and partly sunny for Tuesday. Look for highs to reach the lower to mid 80s with lows in the 60s and warm southerly wind throughout. A shower or thunderstorm is possible Tuesday, but most areas will remain dry.

By Tuesday evening, a few showers or thunderstorms will be possible in the area, while severe storms are expected in the Plains. The cold front to our west will move into the region Wednesday bringing high chances of thunderstorms and perhaps a chance of severe weather.

Wednesday

The central U.S. storm system will make a push east on Wednesday which is our next best chance for thunderstorms. The Storm Prediction Center has a 15% chance of severe weather (equivalent to a Slight Risk, or category 2/5) for areas west of the Mississippi River on Wednesday. However, that could easily change as both the American GFS and European models indicate storms could roll into the Memphis metro late Wednesday afternoon and evening, which is when instability is maximized due to being during peak heating hours. The PM hours Wednesday will be worth monitoring, with storms possibly continuing into the overnight hours. It's too early to define exact storm threats and timing, so stay tuned.

The Storm Prediction Center's severe weather outlook for Wednesday indicates possible severe weather from MO/IL south across the western Mid-South into northeast TX.  This scenario will bear watching as the outlook are will be adjusted daily as the system draws near. Severe weather threats are TBD at this time.

Thursday and Friday

Though the medium-range models disagreed a bit the past few days, they are now converging on a solution that would keep Thursday and perhaps most of Friday dry as weak high pressure builds in behind Wednesday's system. Expect some sun, but likely not "sunny" days with continued warm temperatures, probably in the 80s for highs and 60s for lows.

Next weekend

As we head towards next weekend and Beale Street Music Fest, the crystal ball gets a little fuzzy. Long-range solutions from the computer models offer various solutions, but it appears that scattered thunderstorms will be possible again late in the week as a warm front pull back north across the region. Then, things get even more murky as to when the next cold front moves through, ranging from Saturday PM (European model) to Sunday PM (GFS/Canadian models). For now, we'll call next weekend "unsettled" with daily chances of thunderstorms. The one thing we are fairly certain of is that it won't be as cool as last year's Music Fest. Hopefully it just won't turn in to another Memphis in Mud!

As many of you know, MWN is the Official Weather Partner of Memphis in May, so we'll be keeping a close eye on the weekend and will also keep you abreast of changing conditions, including updates from Tom Lee Park during Music Fest. Stay up to date with our latest thoughts on storm chances via the human-powered MWN Forecast on our mobile apps or on the web.

Speaking of which, the Android app has a new update out (with iPhone releasing in the upcoming week) which adds a couple of features, including the ability to read these blog posts within the app and adding Drummonds, TN to our current conditions providers. We also updated some "under the hood" stuff that will keep StormWatch+ on top of its game. With severe weather season upon us, we strongly recommend you consider having a smartphone option for severe weather alerting and our StormWatch+ service is one of the best! Download links can be found below.

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook, Twitter, and Google+ Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone. Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!

MWN is a NOAA Weather Ready Nation Ambassador

Meteorologist Erik Proseus is an NWA Digital Seal Holder