frostfern

The Euro shows a zone of 500+ j/kg MUCAPE getting into northern IL and far southern MI Thursday night. The mid-level lapse rates will be getting steeper and freezing level lowering due to the upper low nosing in, so even less that 500 j/kg could produce some low-topped storms. The lightning will be in a diminishing trend as the system moves north, but there will probably be a few rumbles everywhere along and south of I-94. It will be a super tight temperature gradient so Wisconsin might get snow while Illinois gets thunder.

I had a bad cough and 102 F fever a couple nights in a row about 2 weeks ago. I get colds and bad intestinal stuff a couple times a year but I don't recall the last time I had full-blown flu symptoms like that. I'd probably have to go back to childhood. Thankfully I was only really sick for about 3 days. I want to the doctor but there was no test. They said 90% likelihood it was influenze B or H1N1 (even though I had a normal flu shot last October). It would have been nice to know for sure what it was and why the flu shot didn't prevent it. I didn't travel anywhere but now it's a little concerning that random celebrity cases are turning up. It's a worry if non-severe cases are slipping through untested.

Yea. This system really lacked instability, even down south. Previous ridge scoured out moisture along the GOM. First thunder will probably be after the 16th. The western GOM is progged to have more juice when next LW trough finally lifts out. The ensambles are showing SW flow developing by then. The southern plains will definitely light up, but thunder could spread further north and east if a stronger low develops and brings the warm sector up. Could also end up being a snowstorm for the GL given the uncertainty this time of year though. Until then it looks like a boring week.

Yea. I think sometimes intense sunshine is unhelpful because it produces a deep dry adiabatic layer. Supercell tornadoes tend to like areas where there the low-level lapse rate isn't too steep. Downdrafts don't become too dominant then. You also get more backing near the ground when the first 1000 feet is a little more stable because there aren't as many dry thermals mixing westerly momentum down from above. The most likely place for big tornadoes usually isn't in the middle of a bubble of high SBCAPE. It's usually around the edge of the SBCAPE bubble (i.e. where there's a sharp SBCAPE gradient). I think tornadic supercells are often pulling in the most unstable air from a slightly elevated layer, but the meso is able to "dig" down and pull in surfaced based air as well. For example, you might have a MUCAPE of 1400 j/kg for a layer rooted around 900 hPa on the "cool" side of an old outflow boundary, but the storm is also pulling in surface parcels with CAPE around 700 j/kg. The surface parcels probably have a fairly high LFC, but the vacuum effect of the meso can get them up there. These parcels have a lot more "backed" momentum profile than those entering the storm from the 900 hPa level, so they can contribute a lot of extra spin to the meso, helping to reinforce the upward vacuum effect. On the warm side of the outflow boundary you might have SBCAPE of 2500 j/kg, but meso's are all weak and elevated due to strong cold pools and lack of near-surface backed flow.

Yea. Tornado outbreaks in March and April are usually going to coincide with abnormal warmth and humidity for the time of year. That doesn't mean you need summer-like temperatures though. Shear is far more important, and low cloud bases / high relative humidity is very beneficial because evaporative cooling from nearby precip won't completely stabilize surface-based storm-inflow. I think Dr. Leigh Orf's work provided some pretty strong evidence that violent tornadoes ingest a lot of surface-based parcels that are more stable than average, yet still realize some positive buoyancy once lifted into the middle levels of the storm by the upward vacuum-suction force of the rotating meso. Hot weather brings you the highest surface based CAPE, but that CAPE can be completely neutralized by just a little bit of precip if the boundary layer is characterized by low relative humidity. The result is many hot-day summer supercells have elevated inflow, and thus never produce tornadoes. Early spring supercells are very good at producing tornadoes because they often form in an environment where instability is more than adequate for strong convection despite high boundary layer relative humidity.

Yea. Missing out on big jet-phased synoptic snow events happens every year, but being in West Michigan most years you at least get the consolation prize of a decent cold stretch with a clipper train and lake enhancement to build up the snowpack. We missed out on that part of winter almost completely this year. Cold snaps have been unusually dry and short lived.

A year like this I'll gladly take 5".

Any other Grand Rapids are folks here? Looks like Lucy pulled the football away yet again. This winter has been so disappointing. It seems like it's just IMBY bad luck for GR in particular as other areas have been hit. At this point I'm ready for spring.