Garrett’s Blog: “Active April Weather”
The typical April severe weather pattern is starting to take shape. April is usually the wettest month of the year and it’s also the peak of tornado season in Arkansas.
Short term: For the next few days, the upper level winds are aligned from the northwest to southeast. We call this “northwest flow” and it’s notorious for busting our forecasts. We’re essentially at the end of a gutter drain pipe for all of the central plains. Anything that develops upstream… travels our direction. These systems tend to peak in the middle of the night west of us and affect our area during the morning from Tue – Thu. There is some uncertainty as to whether or not they’re develop.. so the overall forecast is “chance for rain early in the day… and then in the afternoon with any leftover boundaries”.
Long Term: This is where it gets interesting. The image shown here is the upper level wind pattern for later this week and into the weekend. Notice how the upper level winds are now from the southwest to the northeast. Usually when the cold front parallel’s the upper flow, heavy rain occurs and this certainly looks like the case for the weekend.
The same SW to NE orientation will allow dry air from the southwest to be pushed into the middle of the atmosphere. The drier air above us will accelerate the cooling of rising air making the atmosphere more unstable and more favorable for severe storms.
Another interesting feature is the high pressure situated over Georgia and Florida. The clockwise flow will move lots of moisture from the Gulf into our area. Not only the fuel for the storms but also for heavy rainfall.
As the jet stream energy nears, smaller embedded features will be within the main upper system. These “shortwaves” could serve as the focus for several rounds of severe weather. The timing is difficult this far out because there could be multiple episodes depending on the number of small waves embedded within the big wave. That’s why rain chances look peppered all over the place. The main upper system may not exit until around Tuesday of next week and could even offer some colder than normal temperatures on its departure.
Bottom line… severe weather season is here. Expect several rounds of showers and thunderstorms for the next week and likely for about the next 2 months.