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I disagree with our weather forecasters on TV

Discussion pertaining to Detroit, Ann Arbor, Port Huron and SW Ontario
jadednihilist
Posts: 313
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Re: I disagree with our weather forecasters on TV

Unread post by jadednihilist »

00Z sounding for DTX shows 35 kt winds at 850 mb, which is robust enough to support MCS maintenance. I'm a bit concerned about instability though. Lots of dry air in the sounding compared to the 19Z Green Bay sounding. We would need a bit more moisture aloft to steepen those mid-level lapse rates, but that'll eat away at this storm as it moves east. This increases the impact surface cooling would have on overall instability.

Image

It's worth noting that CAPE represents an upper bound on available thermodynamic energy. It assumes no dry air mixes with a saturated parcel (bad assumption, especially in a dry airmass) and also ignores drag forces. With dry air in place, actual buoyancy of parcels is substantially lower. I'm downgrading my expectations for tonight.
I'm here for a good, hearty debate, to agree and disagree respectfully, and commiserate on the current state of terrestrial radio.
jadednihilist
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Joined: Sun Jun 16, 2019 3:31 am

Re: I disagree with our weather forecasters on TV

Unread post by jadednihilist »

The HRRR doesn't really give the atmosphere an opportunity to recover tomorrow as it develops deep convection to the south, limiting moisture transport up here. It seems like the CAMs are pushing the jet stream a bit farther south than the GFS/Euro, which would support that conclusion.

I'm looking at the 588 dm 500 mb height isohypse as a proxy for southward extent of the 500 mb jet stream. The 00Z soundings show a bit of deepening of the jet with the 588 line between Davenport, Iowa and Springfield Illinois (closer to Davenport). At 700 mb, pretty wide area of 35 kt winds would also support convection farther south as well. I would argue that a southward miss is definitely in the cards tomorrow.
I'm here for a good, hearty debate, to agree and disagree respectfully, and commiserate on the current state of terrestrial radio.
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WOHO
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Re: I disagree with our weather forecasters on TV

Unread post by WOHO »

Severe Tstorms that rolled-thru Toledo during the night, 2:45am, didn't come from the NW like it looked like during the 11pm forecasts, but snuck-up from the SW into the area, and one that rolled thru Wood County at 8am came (pretty fast-like 50mph straight out of the west). Wood County storm was probably the first one all season that had any sort of electrical activity in the way of nearby strikes.
km1125
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Re: I disagree with our weather forecasters on TV

Unread post by km1125 »

As I was watching the radar signatures as the storms rolled across Lake Michigan, I thought it was interesting that when they were leaving the Wisconsin shore, their shape mimicked the shoreline of the state. As they rolled across the lake, it appears they "adjusted" so by the time the made landfall on the Michigan side, they actually mimicked the Michigan shoreline. I don't know what they call that, but how the geography impacts the formation and direction of storms is very interesting. It's very obvious around mountains, but I think it's really interesting how the lakes affect it. I've watched storms roll across the Detroit Metro area and it's interesting what happens to them as they hit the area around Lake St Clair.

I've also wondered how much this really impacts the storm. I've noticed some storms rolling over the Ann Arbor area and it seems like they split when they go over that valley, with some of the storm trending north and some south. Not that they really GO north and south, just that the development peters out going over the valley instead of strengthening like the areas to the north and south. A couple weeks ago I was in the Bay City area the morning after a bunch of storms rolled though there. Ask a couple people how bad they were and some said "Well, it wasn't too bad. Since we're in a valley they kind of skip over us"

Makes me wonder. If there's a valley, is the influence different if the storm is going over them perpendicular to the valley vs parallel to it? How much of a valley (or a hill) does it take to make an influence to the weather pattern and affect storm development?

EDIT: Here's an example I caught today as the storms were rolling over AA:
Image
jadednihilist
Posts: 313
Joined: Sun Jun 16, 2019 3:31 am

Re: I disagree with our weather forecasters on TV

Unread post by jadednihilist »

km1125 wrote: Wed Aug 11, 2021 2:43 pm As I was watching the radar signatures as the storms rolled across Lake Michigan, I thought it was interesting that when they were leaving the Wisconsin shore, their shape mimicked the shoreline of the state. As they rolled across the lake, it appears they "adjusted" so by the time the made landfall on the Michigan side, they actually mimicked the Michigan shoreline. I don't know what they call that, but how the geography impacts the formation and direction of storms is very interesting. It's very obvious around mountains, but I think it's really interesting how the lakes affect it. I've watched storms roll across the Detroit Metro area and it's interesting what happens to them as they hit the area around Lake St Clair.

I've also wondered how much this really impacts the storm. I've noticed some storms rolling over the Ann Arbor area and it seems like they split when they go over that valley, with some of the storm trending north and some south. Not that they really GO north and south, just that the development peters out going over the valley instead of strengthening like the areas to the north and south. A couple weeks ago I was in the Bay City area the morning after a bunch of storms rolled though there. Ask a couple people how bad they were and some said "Well, it wasn't too bad. Since we're in a valley they kind of skip over us"

Makes me wonder. If there's a valley, is the influence different if the storm is going over them perpendicular to the valley vs parallel to it? How much of a valley (or a hill) does it take to make an influence to the weather pattern and affect storm development?

EDIT: Here's an example I caught today as the storms were rolling over AA:
Image

Off the top of my head, there are a couple factors at play as mesoscale convective systems (a broad term to describe thunderstorm complexes that are roughy 100 to under 1000 km in horizontal length) move over large bodies of water like the Great Lakes:

1.) Water surface temperatures. Since water has a specific heat capacity of roughly 4000 J/kg, about 4x higher than land, it takes roughly 4x more energy to raise the temperature of the water surface. That's why as you drive towards the beaches in the early summer, the lake breezes are so cool. However, during the fall/winter as cold air masses move into the region, it takes much longer for the lakes to cool off and we get lake effect precip.

In the summer, these relatively cooler water temps create a shallow layer of stability which inhibit storm development. If the atmosphere aloft is unstable (that is, the vertical temperature gradients are steep) and there's a steady supply of warm moist winds in the presence of a lifting mechanism (like a front), the air parcels in these storms airmass originate above the stable surface layer. That's called elevated convection - and this type of convection can still be quite robust. As the storms approach land, they encounter a horizontal thermal gradient once again, which can affect storm circulation.

2.) Friction. Just like with automobiles and planes, storms are also shaped by aerodynamic flows. Near the surface (about 1 km and below), there's a bunch of turbulence because of air interacting with trees, buildings, hills, etc. This turbulence slows down air flow, which is why winds at the ground tend to be gusty, but winds aloft tend to be more continuous. We call this turbulent surface region the boundary layer, similar to what you would see in water flows in pipes or rivers. Rough surfaces over land produce more friction than flatter water surfaces. The impacts from friction affect internal storm dynamics. These affects are especially pronounced during lake effect season where you'll see friction lead to sinking air upstream of lake effect precip, and rising air downstream. Example:

Image
I'm here for a good, hearty debate, to agree and disagree respectfully, and commiserate on the current state of terrestrial radio.
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Robert Faygo
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Re: I disagree with our weather forecasters on TV

Unread post by Robert Faygo »

We've quickly devolved from major annoyance into major disaster all across Metro Detroit over the last 18 hours with no real sign these training downpours are going to abate.

1/2 million DTE customers in the dark and growing.

While everyone predicted the chance of rain, the amount of widespread damage from wind and rain seems to have caught everyone that forecasts the weather for a living by surprise.
Wellllll... la de frickin da
km1125
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Re: I disagree with our weather forecasters on TV

Unread post by km1125 »

Just heard Michael Estime say something like "one inch of rain over one square mile is 17 million gallons of water"

I did a little math and come up with over 2.5 billion gallons. Is my math wrong or his??
BKRPDM
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Re: I disagree with our weather forecasters on TV

Unread post by BKRPDM »

To jaded or MW, or anyone who might know:
*Customarily, storms of a severe nature seem to lesson in intensity towards the late evening or overnight. I wonder why this hasn’t been the case lately….
*Has this been a relatively rough storm season? It seems like we’ve had some calm summers the last few years. I do remember some stormy summers in the early 1980s.
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Rate This
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Re: I disagree with our weather forecasters on TV

Unread post by Rate This »

BKRPDM wrote: Thu Aug 12, 2021 10:49 am To jaded or MW, or anyone who might know:
*Customarily, storms of a severe nature seem to lesson in intensity towards the late evening or overnight. I wonder why this hasn’t been the case lately….
*Has this been a relatively rough storm season? It seems like we’ve had some calm summers the last few years. I do remember some stormy summers in the early 1980s.
For what it’s worth 1980 was a particularly bad July… there was a Derecho that smacked southeast Michigan with 140+ mph straight line winds. The eruption of St. Helens that year messed with the weather for a couple years. Winter 1982 was very very old.

As late as 10pm the NWS auto forecast box was giving a 10% chance of storms and the hazardous weather outlook was saying storms should be confined around the Tri-cities. When the storm complex hit Kzoo and started dipping down I knew we were gonna get hammered. I did not expect the training and freeway flooding. Lots of branches down and power out. Fortunately I’m unaffected so far.
Donald Trump… In your guts you know he’s nuts.
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WOHO
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Re: I disagree with our weather forecasters on TV

Unread post by WOHO »

According to Cleveland NWS, they had NOT issued a single severe weather warning thru the entire "Meteorological Spring" of 2021, which is unheard of since Doppler Weather Radar. So not jack anything this spring.
June 20th/21st were the very first Severe Thunderstorm Warnings issued for Lucas County since October of 2020.
Then nothing, until the three warnings this week, so only this past week have we seen anything resembling severe weather this summer in NW Ohio, and yesterday saw some significant wind damage for the first time in a long time.

Agree on the 70's having many more severe weather events up thru 1980.
Then a another lull until about July 1992, June 1998, (a year with no summer in 2004?) and a
lull again until June 5, 2010 killer tornado in Wood County, OH and a June 2012 derecho.
Oddities were the two November Tornado events: Nov.10, 2002 VanWert/Tiffin Tornadoes & Nov.17, 2013 P-Burg/Oregon Drive-in tornado).

As far as winter goes, Jan/Feb of 1977, 1978 and 1982 sucked big time along with Dec83/Jan84 and Jan2014 being record cold.
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