Insider Blog: Tracking an active pattern into Easter Weekend
The forecast looks increasingly active leading up to Easter Sunday, and looks to be impactful with or without severe weather.
SETUP:
A deep upper level trough will form over the intermountain west by late week, which will be positioned to keep us in a constant flow of warm and wet southwesterly winds aloft and at the surface.
Within that southerly flow aloft, a disturbance will bring a surface warm front through the region Wednesday night into Thursday.
At the surface, a cold front tied to this warm front will move into the region Friday night. Along this front we'll likely see more thunderstorm development.
This front will stall over the weekend until our upper level trough clears the region late Sunday into Monday.
TIMING & IMPACTS:
On Wednesday, a warm front will lift through the region at the surface. This will bring a chance for showers on Wednesday, but by Thursday morning, an increase in the low level jet (LLJ) to the south of the front will stir a chance for thunderstorms. From Thursday morning to the evening, we will trend drier.
By Thursday afternoon and evening, storm redevelopment is possible, but most likely north of mid-Missouri, near northwest Missouri, Kansas, Nebraska, and Iowa. This is where a severe threat is most likely.
A stout "cap" will be in place on Thursday which will limit storm development, especially near Mid-Missouri, but places along and north of I-70 will have a chance.
Thursday night, the low level jet will ramp up and stir more convection near the low and warm front. Again, this will depend on low placement, but current estimates keep this mostly near the Missouri/Iowa border.
On Friday, the cold front of this system will drag through mid-Missouri, providing a focus for thunderstorms. We'll likely have plenty of warmth and moisture to aid instability locally, but there are questions surrounding the feasibility of a widespread severe weather event.
While the ingredients for severe weather are certainly present, they will have some limiting factors. There will be shear and instability, but the instability profile will be "tall and skinny". This is associated with storms that are less explosive, and may take longer to grow. They also may not grow as deep. They are also more vulnerable to water loading; when raindrops are so numerous they work against updrafts. This will be a concern due to modest to large amounts of moisture, however shear may be ample enough to maintain updrafts.
While all of this may push back on a big and prolonged severe outbreak, we do expect sufficient instability and shear to support a few strong to severe storms. The biggest question is what type of severe storms. The cap ahead of the front will keep things dry until early afternoon. As we get into the late afternoon, better forcing from some mid-level disturbances will likely have storms developing by the evening. While our cap will be weakening, it's uncertain if we'll get storms rooted near the surface. For this, our hail risk is the greatest, as this is a threat that more elevated storms can produce. If storms can become rooted in more surface based instability, then we could see a wind and tornado threat.
With all of this said, storms will likely form during the afternoon and evening along the front. Storms will have their best chance at producing severe weather early, but struggle to continue as we shift to mostly a heavy rain concern.
A flood threat will be a concern, with the flow of storms moving parallel to a stalling front on Friday. This may lead to rounds of rainfall repeating over the same areas for a prolonged period of time. Any excessive rainfall will be compounded by more rounds of rain forecast on Saturday and Easter Sunday.
Total rainfall from Thursday through the weekend could amount to several inches for some. You will likely want to have an alternate plan that keeps you inside on Saturday and Sunday for any Easter egg hunts or related activities.
