frostfern

I really should not have dismissed the possibility of tornadoes at night. Rotation headed straight for Battle Creek is nasty.

BULLETIN - EAS ACTIVATION REQUESTED Tornado Warning National Weather Service Grand Rapids MI 1201 AM EST Wed Feb 28 2024 The National Weather Service in Grand Rapids has issued a * Tornado Warning for... Northern Calhoun County in south central Michigan... * Until 100 AM EST. * At 1201 AM EST, a severe thunderstorm capable of producing a tornado was located near Galesburg, or 9 miles southwest of Battle Creek, moving east at 35 mph. HAZARD...Tornado. SOURCE...Radar indicated rotation. IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely. * This dangerous storm will be near... Battle Creek, Springfield, and Level Park-Oak Park around 1205 AM EST. Brownlee Park around 1210 AM EST. Other locations in the path of this tornadic thunderstorm include Marshall. PRECAUTIONARY/PREPAREDNESS ACTIONS... TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris. Tornadoes are extremely difficult to see and confirm at night. Do not wait to see or hear the tornado. TAKE COVER NOW! && LAT...LON 4242 8530 4242 8472 4225 8472 4217 8529 TIME...MOT...LOC 0501Z 254DEG 32KT 4226 8540 TORNADO...RADAR INDICATED MAX HAIL SIZE...<.75 IN $$ NJJ

Okay. At this time of year in the eastern regions of the US high based storms are usually also elevated and non-severe. So yea, in this context what you said makes sense. It just seemed like an overgeneralization to say "high base" means non-severe, so I responded. No need to nitpick anymore. We both get it.

I remember March 31 didn't have super high dewpoints. Only low 60s at best. Low LCLs AND good instability still happened because it was cold aloft. Same here. The warm sector was a little broader and deep layer shear was stronger though. That seems like the only thing off. The best shear arrives after dark.

I noticed that too. Significant dryline with actual warmth behind it in February is wild.

Anyone else notice the super sharp dryline forming over Missouri and Illinois? I don't think I've ever seen a dryline like that so far north and east.

Sorry for being pedantic. I think you know what you’re talking about but you aren’t using the correct terminology.

Elevated and high based don’t mean the same thing. You can have either one and not the other. Out west you often have high based storms that are still rooted in the boundary layer, because the boundary layer is extremely deep. Storms that move over Lake Michigan are almost always elevated, technically, in the spring and summer because surfaces based parcels are rarely unstable, but the cloud base is often way lower than what you’d see in Colorado, New Mexico, or Arizona. Neither elevated or high based is ideal for tornadoes, but other types of severe weather are not uncommon at all. High based storms over a deep boundary layer are notorious for causing downbursts because the negative buoyancy for downdrafts is extreme. It happens out west all the time. Last spring an elevated supercell a few miles from where I live produced tennis ball sized hail with a surface temperature in the low 50s.

That’s not really true. High based storms can be extremely severe. It’s only really an issue for tornadoes.

With a strong due south wind the lakes can actually help convergence, except for directly over the lake. I think the problem is more the timing. The cap doesn’t really break until after dark. Not that tornadoes can’t happen after dark, and all the other hazards will be there. If the cap breaks early anywhere though, watch out…

Its not like a summer-like cap bust. More just all the convection being north of the surface boundary, or moving north before it has a chance to produce. These things are always so fickle this far north with the moisture strung out. The CAPE is wild for February though.

Is anyone planning on chasing? There is a cap bust risk with this kind of setup.

Its pothole season. I narrowly avoided a pretty deep one today. I hate how Michigan roads are so fragile. Is it like this everywhere?

PNW heat can be muggy, but it’s never “tropical”. Evapotranspiration from all the conifer forests can push the dewpoint up to the low 60s, but I don’t think it ever reaches 70. Triple digits usually happen when the wind blows downhill from the Cascades, and from that direction it dries out some. When it gets muggy (60 degree dewpoints) it’s typically much weaker offshore flow with temperatures in the upper 80s vs near 100. When it really torches the airmass comes from the east side of the Cascades, and then the dewpoint falls into the low 50s.

Yea. Lake Michigan definitely takes the edge off a bit in both winter and summer. Still distinct seasons, but 100F and -20F are more rare here compared to Northern Illinois. You don’t have to travel far to see those more extreme readings though. The interior north gets a lot colder and Chicago gets a lot hotter.

I don’t think interior BC gets 80 degree dewpoints though. I have experienced some PNW heatwaves, and they can be very hot and also humid enough to be uncomfortable, but you never get that steamy tropical feel. It also seems like the most extreme temperatures happen in localized downslope areas. I noticed Olympia Washington hit 110 while Seattle only got to 101. It has something to do with the terrain. There are plenty of extreme places on earth, especially when you consider micro-climates, but the combo of tropical summers and brutal cold winters seems kinda unique to the Midwest US IMO.

Most other places in the world that experience extreme seasonal variation are more arid. The upper Mississippi Valley is kind of unique in how tropical it can get in the summer while still having very harsh winters. I think the only other place similar is the northeastern part of China. I think China is a bit more mountainous though and mountains will shelter some areas. There is no real mountain range anywhere separating the arctic and Siberia from the Midwest US. Same for humidity from the Gulf / Caribbean.

The temperature in GRR has been a bit below what forecast grids have been indicating for the past 24 hours. It was below zero for quite some time last night and earlier this morning. There’s been a pretty sharp gradient through here.

Its crazy to me that the same place that has triple digit hear and 80 degree dewpoints in July and August is this cold in the winter.

Can it be as bad as seamless blocking and smoke the entire months of May and June?

I hate brutal near zero temps with a nasty wind, but I also hate 40s and melting all my beautiful snowpack. Upper 20s is the best, but it never stays there.

Picked up an additional 7” last night with strongest lake effect band I have ever seen locally. I think most of it fell in a 4 hour period between 10pm and 2am. It was a bit lower ratio than normal lake effect. Definitely not 20:1. It came down so hard the flakes were riming. I could hear it hitting the window. Surprised there was no thunder. The weekly total is now over 20” and the ground depth average is now around 14.5” IMBY. Lots of drift variability though.

You don’t need to be anywhere near frostbite to feel that burning. Blood vessels in the extremities always constrict in response to cold and dilate in response to heat. The problem is very fast dilation from a constricted state is painful. Lots of immune response signalers collect in the cold extremities because low blood flow makes them vulnerable. Sudden return of blood activates all the accumulated immune signalers causing lots of burning, swelling, itching, and tingling. A problem I have is finding boots sized to not cut off circulation in my toes. I have super wide feet with a high arch and I’ve had problems with cold toes. Sometimes thicker socks make the problem worse by squeezing my toes even tighter. They also get very itchy after being numb for too long.