***Official 2025 Weather Thread***

awd4cy

Well-Known Member
Dec 29, 2010
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Central Iowa
So I've seen a lot of "We don't usually see warnings this far out" comments lately. Has something changed in forecasting, like AI, or are we seeing changing weather patterns?
Forecasting keeps getting better and better. I always cringe when people say the weather man is always wrong. I think that couldn’t be further from the truth and I’ve noticed even in the last decade forecasting seems more accurate. Sometimes certain events get overhyped, but they usually nail the location and timing.
 

cyfan964

Well-Known Member
Oct 22, 2006
5,115
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I got hit by the White Oak/Nevada tornado last year... 2 weeks of tree removal and cleanup. What are the odds of a tornado hitting the exact same location 2 years in a row. Pretty low right? Someone talk me off the ledge.
 

FerShizzle

garbage man
SuperFanatic
SuperFanatic T2
Feb 5, 2013
15,420
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Des Moines
I got hit by the White Oak/Nevada tornado last year... 2 weeks of tree removal and cleanup. What are the odds of a tornado hitting the exact same location 2 years in a row. Pretty low right? Someone talk me off the ledge.
The odds of you getting hit are the same regardless of whether you have been hit before.
 

awd4cy

Well-Known Member
Dec 29, 2010
27,946
19,573
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Central Iowa
I got hit by the White Oak/Nevada tornado last year... 2 weeks of tree removal and cleanup. What are the odds of a tornado hitting the exact same location 2 years in a row. Pretty low right? Someone talk me off the ledge.
Don’t want to freak you out, but I saw it happened in Arkansas. Same neighborhood just different damage to same houses. They were hit in may of last year and March this year. That is just insane.

 
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cycloneG

Well-Known Member
Mar 7, 2007
15,864
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Off the grid
The odds are still extremely low.
dumb-and-dumber-lloyd.gif
 

CryoLegion

Member
Jul 27, 2024
29
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Ames, IA
1745599552095.png
It's still a little early for the higher resolution models (HRRR, NAM) for Monday but the latest GFS is showing actual convection and potentially discrete/embedded supercells in Iowa from 4-10pm on Monday.
1745599621397.png
Here is a sounding for Ames, IA on 4pm on Monday- decent low level curvature that gets better as the night wears on, upper 60s dew points, over 3,000 Surface-Based CAPE, and 54 knots of wind shear is a very potent setup for all modes of severe weather if a supercell moves over, even strong tornadoes. Again the main thing that is stopping this from being an upper upper echelon event is the helicity- around 200 helicity is good for tornadoes but a little low for the really violent ones like the ones that hit Greenfield last year. Of course an unlucky boundary interaction and that could be overcome.
1745599886225.png Another potential limiting factor for a tornado outbreak is Iowa will likely have near total cloud cover for most of Monday (this is Monday morning at 10am) and that could dampen the instability somewhat, though not nearly enough to prevent severe weather outright especially given there is the occasional break in the clouds.
1745600376629.png Map of helicity at 7pm on Monday (still a tad early for helicity tracks)- blue is 100 m2/s2, orange is 200 m2/s2, red is 300 m2/s2, purple is 400 m2/s2. The SPC defines the ideal environment for strong tornadoes to be around 247-402 m2/s2 helicity: https://www.spc.noaa.gov/exper/envbrowser/, and the higher helicity values are generally gonna be east of I35, so I think that's looking to be where the largest potential for tornadic action will likely be from this model- of course that can change as high resolution models come into play (and GFS is historically very bullish and somewhat chaotic on tornadic setups).
 
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CryoLegion

Member
Jul 27, 2024
29
30
13
Ames, IA
1745601763792.png
It looks like the CSU-MLP model (one of the AI models that is a big reason why forecasting has become so accurate this year) is currently placing the biggest risk over eastern Iowa, western Wisconsin, southeast Minnesota which lines up with what I said above with helicity, though again that can change in 4 days (yesterday it was right over central Iowa)
 

clonedude

Well-Known Member
Apr 16, 2006
32,850
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So are we talking about spotty tornadoes, or is there a possibility of a widespread wind event like a derecho happening?
 

jsb

Well-Known Member
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SuperFanatic T2
Mar 7, 2008
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I got hit by the White Oak/Nevada tornado last year... 2 weeks of tree removal and cleanup. What are the odds of a tornado hitting the exact same location 2 years in a row. Pretty low right? Someone talk me off the ledge.

I know someone whose house was destroyed in a tornado in 2000. They rebuilt the exact same house and it was destroyed in 2008 in another tornado.
 

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