A beautiful Spring Palm Sunday going on right now throughout the area, with plenty of sunshine and readings in the 70's. Let's take a closer look at what's going on, including the possibility of some severe weather tomorrow...
GORGEOUS RIGHT NOW: Not a whole lot more to say beyond that. Have a look at this image...
Just some high cirrus clouds evident on the visible satellite picture right now, but as you head west, clouds increase with some showers and thunderstorms in the nation's midsection right now, in Minnesota, South Dakota, and Nebraska.
CHANGES ON THE WAY: We'll get through the rest of today and this evening is good enough shape, but then we'll have to be aware as a surface low moves from Wisconsin into Lower Michigan over the next several hours. Daytime heating tomorrow with that low in the neighborhood will touch off some showers and thunderstorms, and not all of these will be garden variety.
SEVERE WEATHER POSSIBLE TOMORROW: The Storm Prediction Center is suggesting the possibility of severe weather in the Lower Peninsula tomorrow. The entire lower part of the state is in a "marginal" risk for severe weather tomorrow, with the standard slight risk impacting South Central and Southwest Michigan, including the west end of both zones of the blog...
The good news is that I do NOT anticipate any tornadic activity with the storms if they are able to fire and get rowdy. The thinking is a semi-organized squall line of storms that will have strong straight line winds and some small to moderately-sized hail as the primary threats. Taking a look at some of the severe weather data from our fearless forecast models, I'm not seeing a whole lot to worry about as long as you take time now to secure anything you don't want to go hunting for. Let's have a look at a couple of graphics...
The map above represents a index that we use in severe weather forecasting called SBCAPE, which means Surface Based Convective Available Potential Energy. The watered down version is, if a storm can fire and tap into this air mass, how much "energy in the battery" is there to run the storm? That is a HIGHLY oversimplified explanation of this index, but it helps explain what I'm looking at. We note that the value for this index is about 1000-1250 j/kg. Enough to get you a rowdy storm or two, but you'd want to see a higher number for a more robust severe threat. The other thing I notice is that there's not much of a "cap" in the forecast sounding data.
CAP = A layer of air off the ground that is warmer than the surface air. In a thunderstorm situation, air is prevented from rising through the layer until sufficient heating has occurred and energy is available for it to become buoyant and lift thru the layer. The longer this lifting process is delayed, the more energetic and unstable the air becomes, which can lead to more intense storms. Think of a covered pot of boiling water. The longer the pot is left to boil and covered, the bigger the steam plume when you remove the lid.
Again, that explanation is HIGHLY simplified, but hopefully you get the idea. You want some kind of a cap to delay the onset of storms and "charge the battery" more for severe weather. Not having much of one means that the first chance the air has to rise, it will, so storms will likely initiate sooner, and with less vigor than if there's a cap to contend with.
Please understand, I am in no way saying the severe threat tomorrow is zero. You expect the unexpected when you're talking about severe weather. I'm saying that the most likely modes are damaging straight-line wind and some marginally severe hail (probably nickel-sized at best).
DETAILS ON THE SEVERE: Timing appears to be tomorrow afternoon or evening. Chances of this impacting the evening drive home in South Central Michigan appear to be low. This appears to be more of a near dusk/sunset affair for our part of the world. A reasonably solid line of storms with some marginally severe straight-line gusts, and hail up to nickel sized should fill the bill right now. We'll check and see if we have any radical changes.
OK, WHAT ABOUT AFTER?: Well, we won't have any more severe for a while, and I don't even thin we get much widespread rain for the next few days. It'll cool off a bit from recent days, and I anticipate them still above normal, but single digits above, and not 15-20 degrees or better as we have been. Aside from that, I'm not overly concerned about rain. I'll mention the chance of a stray shower on Thursday out ahead of a weak upper wave that will touch off some rains back to the south and east in more scattered fashion. The next credible rain chance comes Saturday, when a strong surface low that will be way up in Canada will drag a cold front along behind it that could set off scattered to numerous showers.
Here's your forecast for Jackson and vicinity:
Tonight - Clouds thicken as the night progresses, still mild though, lows roll back to near 57.
Monday - Mainly cloudy, still mild, afternoon and evening showers and thunderstorms, especially east of I-69. Some of these could be marginally severe, including gusty wind and hail that is nickel-sized or smaller. Highs near 73, then cooling as the system approaches late.
Monday Night - Cloudy and cooler, a lingering shower or lonely thunderstorm may be around until midnight. Low 47.
Tuesday - Clearing skies and noticeably cooler, but still seasonal. High 60.
Wednesday - Mainly sunny to start, some PM clouds developing, a touch cooler still, high only 59.
Thursday - Partly to mainly cloudy, we can't rule out a lonely shower in a spot or two, High 62.
Friday - Mixed sunshine and warmer, high 65.
Saturday - More clouds than sunshine, some widely scattered PM showers are possible. Warmer, High 73.
There's a look at your forecast, I hope that you have a wonderful rest of your Sunday!
