Michigan Radio & TV Buzzboard

https://www.spc.noaa.gov/products/md/2021/md1343.html

Looks like Metro Detroit has been added to the watch now. The CAPE is sufficient for deep convection and this tropically moist airmass should slow cooling tonight, so the SPC has enough confidence to suspect these storms could make it here before completely weakening below severe limits. The worst of the storms will still be in Mid-Michigan where it's been quite active this afternoon.

Those storms have meant business today. Bad things can definitely happen when you mix this kind of wind shear with a deeply tropical environment. The completely saturated troposphere over southern Michigan has a higher specific heat capacity than a typical airmass, so it will take longer for things to cool off tapering the rate that these storms decay.

I definitely believe that if you're on the northern half of Metro Detroit, you should prepare for some rough weather in the form of damaging winds and isolated tornadoes (the higher surface vorticity will travel along the outflow boundaries and cold front thats pushing these storms S/SEward). I do think these will start weakening to near or below severe thunderstorm thresholds somewhere in the vicinity of the I-94 corridor, so I do agree with including I-94 counties to the watch.

One really useful tool I like to use to assess the evolution of the strength of the updrafts is the really high resolution GOES-16 near infrared satellite imagery. The convection is higher in the atmosphere where there are colder brightness temperatures, and you can see the strong updrafts moving into Genesee and St Clair counties right now. This, and the area immediately downstream, is where the current severe weather threat remains the greatest.

https://weather.cod.edu/satrad/?parms=m ... =undefined

MWmetalhead wrote: ↑Sat Jul 24, 2021 7:42 pm NWS Pontiac has finally issued a severe tstorm warning for Oakland. Alexa and AAA both notified me instantly within a microsecond of each other.

Livingston County is also included.

The "tornado possible" verbiage that has been quite common with today's warnings is included.

The velocity data within ten miles of the radar site is so incredibly noisy; NOAA should do something about that. One of the crappier radar sites I've seen in that regard.

It's really hard to clean the signal so close to the radar because the beams pass so low to the ground. You often get nonhydrometeors like dust, insects, and birds that get scattered back to the radar along with the rain. However, the tradeoff is that if you see strong rotation near the radar, that rotation is almost certainly making it to the surface and that's why we have the tornado warnings. The lowering of the correlation coefficient in the vicinity of the velocity couplet also confirms that tornado debris is being observed by the radar as well. Extremely dangerous situation.

https://www.spc.noaa.gov/products/md/2021/md1344.html

Heads up for anyone in southern Oakland, Macomb, Washtenaw, Wayne, and potentially even Lenawee and Monroe counties.. as well as southwest ontario including Windsor and Essex.

The most intense band of convection continues to be the
activity moving southeastward at an erratic/25-35-kt pace across
southeastern Lower MI. In addition to damaging gusts, a couple
tornadoes appear to have occurred in the last hour, within short-
lived but intense embedded mesocyclones. This potential will
continue for another hour or two as the convection encounters a
pocket of relatively high-SRH air (effective SRH 150-350 J/kg),
based on radar imagery, VWP analysis and objective mesoanalysis
data.

Definitely keeping an eye on the convergence of the two lines just northeast of Ann Arbor. That could also potentially produce a brief tornado in eastern Washtenaw and western Wayne county. That's also coinciding where the strongest updrafts are according to the latest satellite imagery.