BENEFICIAL RAIN FOR MOST, STRONG STORMS FOR SOME

The umbrellas and rain jackets will be quite handy for any outdoor activities on Easter across the Midwest as a strengthening storm system swings through the region bringing a threat of severe weather and heavy rainfall. While the highest severe weather chances will be mainly south of the area we could still see a few strong storms, and nearly everyone will see beneficial rainfall.

Sunday, a Level 3 of 5 Risk, an Enhanced Risk, is in place across much of Missouri. A Level 1 of 5 Marginal Risk clips southern Iowa and almost reaches the Quad Cities. I would not be surprised at all if this did expand father north depending on trends on how far the warm front advances.

Down south in the Enhanced Risk area along and south of the warm front several tornadoes are possible. Overall instability is kept in check with this event due to forecast cloud cover and morning rain, however rather strong wind shear will likely compensate for the lacking thermodynamics. That warm front will need to be watched very closely through the day as it could be a focal point for tornadoes.

Several of the high resolution weather models indicate the potential for rotating thunderstorms clipping southeast Iowa and west-central Illinois Sunday evening with a few models pushing the warm front farther north almost all the way to the Quad Cities. It will be a game of just how far north the triple point (the intersection of the low pressure, cold front and warm front) reaches by 7 p.m. Rotating storms does not always mean tornadoes, but could also bring large hail.

One severe weather model that has had recent success is the up-and-coming RRFS. It remains experimental at this stage but is improving. It is along the lines of a few of those models that brings that triple point into southeast Iowa and west-central Illinois by 7 p.m. The bottom line here - don't sleep on the severe weather risk. Make sure you are paying attention to the weather and any watches/warnings issued. The primary window for the area will be 4-9 p.m.

While the severe weather threat is a little more unlikely for most in the area, the widespread beneficial rain is more certain. Model guidance paints a broad-brushed 1"+ for much of Iowa, Illinois and Wisconsin. The heaviest rain will fall across Missouri and Arkansas over the next 48 hours where flash flooding is a much bigger concern.

Moisture content of the atmosphere late Sunday will be in the 90th percentile for climatology - a pretty strong signal for heavy rain especially given the forecast calls for widespread showers and thunderstorms. Precipitable water, a measurement of the moisture content of the atmosphere, will be over 1.25" - healthy!

Looking ahead to the rest of the week, the overall upper-air pattern holds active signals with potential bouts of rain and storms, but it's rather limited confidence given the lack of a strong upper-level low. It appears there will be chances for rain late Tuesday, again late Wednesday, and again as we head into the weekend. With that said, neither of these look particularly heavy or significant at this point in time.

A national view of rainfall Wednesday night to Thursday night has heavier rain totals across the Central Plains with more meager amounts closer to home. We will certainly take what we can get!

Before we wrap this up I did want to touch on the severe weather event in the region on Thursday. We saw a lot of reports of hail in the area with the tornado threat mainly kept to southwest Iowa and southeast Nebraska. One of the more notable tornadoes was over a mile wide near Essex, Iowa well past sunset.

Despite the massive size (1.11mi) the tornado was rated EF-1 as it was mainly in a rural area and thankfully did not hit anything to justify a stronger rating. Most damage was to power poles and trees, with a few unfortunate strikes on outbuildings. A few homes did sustain roof damage as well. Thankfully no injuries were reported.

The preliminary survey from the Omaha, Nebraska NWS office originally had the tornado at a staggering 1.78 miles wide. That would have made it the largest on record in Iowa state history. However, the survey was corrected on Saturday to bring it down to 1.1mi wide. That is why the initial surveys are always considered "preliminary" as they can change with new information and better analysis. I put together a top-25 list for the state of Iowa and you can see five of the 25 are from the last two years! Wild times in the Midwest.

Have a great weekend friends,

-Meteorologist Nick Stewart