Severe Wx / Flooding Rain Event Combo: April 2-6, 2025

[tron777]

In addition to thew severe threats we are watching for Wed and Thurs, the SPC has us outlooked for severe wx (it's close for Cincy) on Fri and Sat too. The threat is south of us by Sunday.

[tron777]

Just the synoptic winds tomorrow will be gusting in the 40-50 mph range per models

No doubt! The strong southerly flow is going to be ridiculous on Wed, esp if we get some sun to help mix those higher winds down.

[tron777]

Good morning AV family! I agree with the forecasts on here. It doesn't look good and quite frankly I can't recall the last time I saw this much QPF printed out for such a large area that included us (echoing Bgoney's thoughts). Let's just hope the HRRR doesn't verify because it looks downright scary for Wednesday afternoon/evening. Picked up over an inch of rain with the Sunday night-Monday morning event so ground is already primed.

12Z HRRR continues a pretty nasty looking signal Wed evening for severe wx.

[tron777]

[tron777]

I thought the HRRR was bad, this is down right scary from the `12Z NAM. Image valid for Wed night near CVG.

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[Bgoney]

Looks like the short range hi-res models really want to strengthen the storms as they enter our SE Indiana counties and west of 71 , in that 3am-7am range with fullest potential

[tron777]

BG's call for rainfall. I pulled it from this mornings blog video. Wow... look at this! I thought it was a snow storm forecast at first.

WAVE 3 Rain.png

[tpweather]

What a wonderful video by Brian and when he harps on something you know its going to be a big event. The severe weather has always been a concern of mine for several days and this is similar in some ways this past Sunday but also different in other ways. The storms are going to come to a stop or nearly stop after mid-night Wednesday. The problem is they will still be happening and if you get into that 3a-9a period this can not only continue the severe portion but really heavy rains.

This past Sunday the temps and dewpoints never got out of hand but on Wednesday a quick climb for both and usually when you see a big climb like that the atmosphere is telling us something is going to happen and even this past Sunday without the climb the storms were stronger than I expected.

Yes nowcast as always but watching the short-term models over the next 36 hours will be important and they hopefully will narrow down some of the worst weather.

Flooding will happen but how bad and where is still somewhat of a guess because we are in April and some vegetation has started plus the ground is not frozen and not dealing with snow melt. Flash flooding and that can occur especially if get a 2-4 hour period where its pouring and especially each day the ground will only be able to hold so much water.

After I watched Brian's videos I increase the totals locally and going 6-8 inches. Can that change and sure but seems like 6 inches is the lower amount for most folks locally. I know somebody will complain they got 4 inches and guess be happy if that happens.

BTW my son expecting another 3-5 inches of snow and he is getting close to the normal output for a season which is in the upper 50's for total snow. He mentioned his pond is overflowing and that is complete opposite of what happened last year.

My guess this forum is going to be very busy over the next 5 days or so and all we can do is gather data and see what is happening to the west and try to stay ahead of the forecast which again will not be perfect for every location but we try to narrow down that as quickly as possible.

[tron777]

Get done today anything outside you need to get done. You may have part of tomorrow also as long as the warm front isn't active in the morning of course. However, the wind will be cranking regardless of storms so there's that.

[mikeyp]

Any thoughts on how high the river will get?

[Bgoney]

Kind of hard to comprehend how much qpf potential we have going on here. That’s not your normal skinny axis of heavier rains , that’s a couple hundred mile wide band of 6”-12”+ and 4-6” surrounding that on either side .

[Pepper]

Concerning Wednesday what is timing of the bad weather expected/

[MVWxObserver]

Last spring Darke Co. had a touchdown in March and another in May.

Talk about a queasy stomach re late day tomorrow and tomorrow night. My folks and I miss our finished basement as here at this house they have a walk-in closet (that can still be cramped but better than nothing) and I have the main bathroom (thankfully doesn't have a window).

Too bad these set up situations tend to be nocturnal often in our part of the OV but thankful we have NOAA radios e.g. etc.

Prayers and thoughts with everyone in the OV etc. over the coming days.

[cloudy72]

I thought the HRRR was bad, this is down right scary from the `12Z NAM. Image valid for Wed night near CVG.


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That is the classic loaded gun sounding! Very scary indeed!

[tron777]

Any thoughts on how high the river will get?

It really will depend on how much falls upstream and into the tributaries of the Ohio upstream from Cincinnati. That will take longer to respond whereas creeks and streams and smaller rivers, we will see a much faster response.

[tron777]

Kind of hard to comprehend how much qpf potential we have going on here. That’s not your normal skinny axis of heavier rains , that’s a couple hundred mile wide band of 6”-12”+ and 4-6” surrounding that on either side .

I don't recall ever seeing such an expansive area of precip from a non-tropical system. This is a very rare set up for us indeed. The Gulf is wide open totally unblocked from S US t-storms as the storms will be here instead. Low to mid 60s for dews isn't too shabby for early April either so PWATS should be high for the time of year. Then if that front stalls for 3 or 4 days and we get 3 nights in a row of heavy rain, then those high end totals are for real. If the location changes each night then it'll be more widespread but lower amounts like 4-6" or something. I can't believe I am saying 4-6" is on the average end of the spectrum.

[tron777]

Concerning Wednesday what is timing of the bad weather expected/

If the warm front stays quiet in the morning then we are good until the late afternoon or evening hours. We need to see what happens very early Wed morning first with that warm front. If it is active then we get severe wx with it too in that 4 - 8am range Wed morning. Most models have us dry though at this time so anything early on Wed has a low chance at this time, but certainly not zero.

IMO, if Wed morning is dry, that is bad news for later on. We will have plenty of heating and CAPE to work with which we did not have on Sunday. Dynamics on Sunday were great and they should be Wed night too. Probably even better! But if we get that expected CAPE Wed night could be a busy one for us. Stay tuned is my best advise right now.

[tron777]

My God... 9.07" at CVG from the 12Z GFS - event total then an additional 0.05" QPF that falls as snow Mon night with a little clipper like system. What the hell is going on?!?!? Wow... I cannot believe the QPF totals we are seeing here.

[tron777]

12Z Euro coming in now and it is active with the warm front for Wed morning. Event total rainfall at CVG is 5.93" so almost 6" And that is on the lower end of the model range. Man oh man!

[Bgoney]

SPC afternoon update



Mid Mississippi Valley to the Lower Ohio Valley...
Thunderstorms will likely be ongoing from northeast Texas to the
Upper Midwest at the beginning of the period. East of this activity,
a warm front will surge rapidly north across Illinois and Indiana
with mid 60s dewpoints expected across the Mid-Mississippi Valley to
the Lower Ohio Valley by mid-day. As temperatures warm into the
upper 70s to low 80s, moderate to strong instability will develop by
early afternoon. A cap, centered around 700mb, should keep deeper
convection suppressed for much of the day. However, as height falls
overspread the warm sector after 21Z and ascent increases in the
right entrance region of the upper-level jet, this cap will erode.
Simultaneously, even richer low-level theta-e, with upper 60s
dewpoints and mean mixing ratio in excess of 14 g/kg will advect
into the mid-Mississippi valley. This will provide an environment
for explosive supercell development given 45-55 knots of effective
shear. In addition, low-level shear will support the threat for
tornadoes.

A broad, strong low-level jet will be present across the warm sector
for the entire day. However, there will be some relative weakening
during the 18-22Z period. This may limit the tornado threat
initially, but by 00Z, most guidance shows a renewed low-level jet
strengthening and elongating of the hodographs. Therefore, the
primary threat could be hail for a few hours during the evening
before the tornado threat increases by 23Z-00Z and persists into the
evening hours. Orientation of the storms and potential for training
do provide some uncertainty, but in the moist environment, expect
multiple mature supercells to persist into the evening when very
strong low-level shear develops. Multiple strong to potentially
intense tornadoes are possible during this period

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[tpweather]

I agree Les and that is why I moved my numbers up and have 6-8 inches locally. Rare event to say the least and yes sometimes folks say that and its like don't you remember last year when this happened. That is not the case here and though the event has not started yet and really its the final outcome that will determine how rare but all indications is this is going to be at least one of those top 10 events in terms of rainfall.

Flooding is a concern especially smaller rivers,creeks etc. For the major rivers its just a little to soon to see how this shakes out. No doubt the major rivers will rise but will they get into the major flood range. I have no ideal and my guess the folks that take care of the river forecast are going to be making several updates over the 5 day period.

[tpweather]

I see the change for the severe output. The area in western Kentucky and Tn no doubt looks like a place that may see the most tornado's later Wednesday and early Thursday. We are not out of the woods either but that could be quite explosive imo.

[Bgoney]

Severe percentages stayed the same for cvgland except for hail which increased

IMG_3384.jpeg

[tron777]

I agree Les and that is why I moved my numbers up and have 6-8 inches locally. Rare event to say the least and yes sometimes folks say that and its like don't you remember last year when this happened. That is not the case here and though the event has not started yet and really its the final outcome that will determine how rare but all indications is this is going to be at least one of those top 10 events in terms of rainfall.

Flooding is a concern especially smaller rivers,creeks etc. For the major rivers its just a little to soon to see how this shakes out. No doubt the major rivers will rise but will they get into the major flood range. I have no ideal and my guess the folks that take care of the river forecast are going to be making several updates over the 5 day period.

My 4-6" maybe too low for sure. I think I'll go more in line with you and now say 6" is the min amount instead of 4". There's the mod risk area from the SPC too. Figured that was coming.

[tron777]

...WIND ADVISORY IN EFFECT FROM 10 AM WEDNESDAY TO MIDNIGHT EDT
WEDNESDAY NIGHT...

* WHAT...South winds 15 to 25 mph with gusts up to 50 mph expected.

* WHERE...Portions of east central and southeast Indiana, northern
Kentucky, and southwest and west central Ohio.

* WHEN...From 10 AM Wednesday to midnight EDT Wednesday Night.

* IMPACTS...Gusty winds will blow around unsecured objects. Tree
limbs could be blown down and a few power outages may result.