***Official 2025 Weather Thread***

jsb

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What does it drain into, it’s possible that river is high so it slows downs its tribs that drain into it. 5” in a week is enough to bring most streams up on their own though. That’s an April’s worth of rain in a week.

Yeah, that river isn’t unusually high. Like I said, they’ve lived there for 43 years and the creek flooding has been a constant issue. They know when it will crest based on the amount of rain received up stream, they know when it will start to go down. They know how long the corn can be under water. It’s not crazy it would be flooded a bit. But the amount of flooding and the fact that it only started going down today is very weird.
 

NWICY

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Sep 2, 2012
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Yeah, that river isn’t unusually high. Like I said, they’ve lived there for 43 years and the creek flooding has been a constant issue. They know when it will crest based on the amount of rain received up stream, they know when it will start to go down. They know how long the corn can be under water. It’s not crazy it would be flooded a bit. But the amount of flooding and the fact that it only started going down today is very weird.
Beavers didn't happen to create a dam downstream did they? It would be unusual but not unheard of.
 

Pope

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The odds of you getting hit are the same regardless of whether you have been hit before.
I always laugh whenever I hear folks say the odds of something happening a second time are even lower.

I've joked that I should smuggle a bomb onto the plane whenever I have to fly because that would make the odds of TWO bombs being smuggled onto the same plane infinitely small.
 

TornadoTouhou

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Jul 27, 2024
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Ames, IA
So what FranCon level can we expect? We need to keep the chart alive for his stay in Iowa. His facial expressions alone can relate to the level of storm severity. :)
Well, it's still very uncertain at this range- if you watch local forecasters or check weather models there is basically no convection (storms) in central Iowa for the entire day on Monday.

The NAM 3km CONUS is the only high resolution model (CAM) RN that is showing storms anywhere in our area in Monday, it would be at midnight on Monday and could pose a spin-up tornado threat:
1745757812111.png
The more experienced forecasters at the SPC are throwing this out because it doesn't seem realistic given the strength of the low level jet and the parameter space (dew points, wind shear, instability), but some of the meteorologists at local NWS offices and local meteorologists in Des Moines news channels are not discounting the possibility of a "blue sky" bust.

NWS Des Moines at the moment thinks this sequence of events will play out on Monday: https://forecast.weather.gov/produc...MX&product=AFD&format=CI&version=1&glossary=1

-A bunch of storms might form, probably discrete/semi-discrete, right over I-35, from Minnesota down to Fort Dodge/Ames, IA at 1pm tomorrow.
-This bunch of storms would move eastward and be the biggest risk for strong tornadoes for the day.
-A line of storms will enter western Iowa from Nebraska at 7pm likely into the southern part of the state and arrive at I-35 around 10-12pm, at this point the tornado threat will be diminished.
-There could be activity south of the first bunch of storms in south-central Iowa, but it doesn't look likely. Therefore there could be a "gap" in central Iowa between these two systems.
-Storm motions will be fast at 40-50 mph, so not a lot of warning time but also tornadoes are unlikely to deal as much damage- the EF2 tornado that hit Story County last year likely would have been rated higher if it wasn't moving at 60 mph just SE of Nevada, for example.

All this is VERY uncertain, and none of the models are showing this or even storms convecting in central Iowa which is a source of controversy among meteorologists. So I guess keep an eye out on updates.
1745758684803.png
Just to highlight the uncertainty, the Weather Channel is showing only a 24% rain chance for Ames, to the point where they are not even calling for it to be a day with any precipitation (besides a stray storm in the morning).
 

Cyhig

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Nov 29, 2017
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The more experienced forecasters at the SPC are throwing this out because it doesn't seem realistic given the strength of the low level jet and the parameter space (dew points, wind shear, instability)
Forecasters at the SPC looking at the high resolution models

IMG_5142.gif
 
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cycloner29

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Dec 17, 2008
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Ames
Well, it's still very uncertain at this range- if you watch local forecasters or check weather models there is basically no convection (storms) in https://images.app.goo.gl/umzsqCBj63HbD5ut8central Iowa for the entire day on Monday.

The NAM 3km CONUS is the only high resolution model (CAM) RN that is showing storms anywhere in our area in Monday, it would be at midnight on Monday and could pose a spin-up tornado threat:
View attachment 148606
The more experienced forecasters at the SPC are throwing this out because it doesn't seem realistic given the strength of the low level jet and the parameter space (dew points, wind shear, instability), but some of the meteorologists at local NWS offices and local meteorologists in Des Moines news channels are not discounting the possibility of a "blue sky" bust.

NWS Des Moines at the moment thinks this sequence of events will play out on Monday: https://forecast.weather.gov/produc...MX&product=AFD&format=CI&version=1&glossary=1

-A bunch of storms might form, probably discrete/semi-discrete, right over I-35, from Minnesota down to Fort Dodge/Ames, IA at 1pm tomorrow.
-This bunch of storms would move eastward and be the biggest risk for strong tornadoes for the day.
-A line of storms will enter western Iowa from Nebraska at 7pm likely into the southern part of the state and arrive at I-35 around 10-12pm, at this point the tornado threat will be diminished.
-There could be activity south of the first bunch of storms in south-central Iowa, but it doesn't look likely. Therefore there could be a "gap" in central Iowa between these two systems.
-Storm motions will be fast at 40-50 mph, so not a lot of warning time but also tornadoes are unlikely to deal as much damage- the EF2 tornado that hit Story County last year likely would have been rated higher if it wasn't moving at 60 mph just SE of Nevada, for example.

All this is VERY uncertain, and none of the models are showing this or even storms convecting in central Iowa which is a source of controversy among meteorologists. So I guess keep an eye out on updates.
View attachment 148608
Just to highlight the uncertainty, the Weather Channel is showing only a 24% rain chance for Ames, to the point where they are not even calling for it to be a day with any precipitation (besides a stray storm in the morning).
1745760380136.png
 

jsb

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Mar 7, 2008
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Beavers didn't happen to create a dam downstream did they? It would be unusual but not unheard of.

Sure could be. I doubt a beaver dam would cause this much. But maybe. It’s probably just a fluky thing. But I’ll be interested in how it floods the rest of the year. It went down significantly last night and is off the road.
 
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CychiatricWard

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Sep 27, 2017
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Des Moines
Are we seeing rain tomorrow or what? Weather channel shows hardly any chance for rain tomorrow but the outlook says high chance for storms. Is there a timing to this thing? Might miss us?
 

CrossCyed

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Mar 30, 2006
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SPC moving Moderate Risk (4/5) farther north.

Much of Central Iowa now Enhanced (3/5)

...Upper Midwest...
After coordination with affected WFOs, primary adjustments have
occurred along the southern extent of the severe probabilities to
account for a more conditional, but still potentially significant
severe threat.

An arc of elevated thunderstorms will be ongoing at 12Z Monday from
ND across the Upper MS Valley. Isolated large hail will be possible
with these morning storms as they move east-northeast. Additional
elevated storms will redevelop towards midday/early afternoon to the
northeast of the aforementioned surface low. This will slow the
advancement of the surface warm front into central MN, but
strengthen differential surface heating across the baroclinic zone,
with greater warming nosing north from NE into southeast SD.
Surface-based storm development should occur by mid-afternoon across
a portion of the Mid-MO Valley into southwest/west-central MN along
the dryline to surface low. Large hail should be the primary initial
threat, but cells may congeal into linear clusters, especially
near/across the warm front. A mix of hail/wind/embedded tornadoes is
likely, with the latter increasing with southern/eastern extent
during late afternoon owing to stronger low-level shear across
southeast MN/northeast IA into western WI.

Open warm-sector storm development ahead of the dryline is nebulous
with low confidence on the degree of ascent ahead of the dryline
given the synoptic setup. Conditionally, both the buoyancy/shear
parameter space is volatile and supportive of potential for multiple
long-track, tornadic supercells. Timing of mid-level height falls
tends to favor the evening period after peak heating but CAM
signals, outside of the 12Z FV3, are sparse. Greater large-scale
ascent appears focused from far northeast IA into WI. This region
remains the most favorable for discrete warm-sector development
during the evening. Otherwise, upstream linear clusters from
southern/eastern MN will likely spread across northern/central WI
into parts of Upper MI with a mixed mode of all hazards persisting,
before eventually weakening overnight.
 
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FDWxMan

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Jan 31, 2009
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Des Moines
There are ingredients there conceptually, but based on my experience forecasting this area over the last 20 years, we're (DSM and probably Ames) aren't in what I would highlight as the best position relative to the low.

Not saying things can't or won't happen, but based on some local pattern recognition, I'm not surprised or disagree with the adjust in probabilities.
 

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