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

[tron777]

50 mph is the new peak gust at CVG.

[tron777]

Seeing a few showers now over IN and KY well out ahead of the main line. We will need to watch these to see of any of these can grow in intensity or not.

[tron777]

So far, the cap is holding and those showers may even fizzle out in time. However, look at the visible. Clouds continue to erode ahead of the line in the Plains. Not good IMO... This event maybe rocking and rolling throughout the night.

[tron777]

80 / 62 now at CVG, 81 so far for my high.

[tpweather]

So far, the cap is holding and those showers may even fizzle out in time. However, look at the visible. Clouds continue to erode ahead of the line in the Plains. Not good IMO... This event maybe rocking and rolling throughout the night.

I agree Les and really the cap holding in this case is probably not good as this will leave the atmosphere here locally in better shape for severe storms to keep their intensity later tonight. Do we see any long lasting tornado's tonight and that is possible and those could be stronger than the ones Sunday. Going to be a long night and my guess the power outages this go around will be much higher than this past Sunday.

[tron777]

18Z HRRR shows those little showers moving thru but nothing that would impede future t-storm development. Anytime after 10pm we are fair game. The sounding looks pretty good still.

hrrr_2025040218_009_38.99--84.62.png

[tpweather]

The HRRR model has changed very little and gives us more confidence over the next few days. The NAM is one that can be out there with some crazy outputs and sure it catches some bigger events but still has the northwest bias even in these types of events.

[tron777]

The HRRR model has changed very little and gives us more confidence over the next few days. The NAM is one that can be out there with some crazy outputs and sure it catches some bigger events but still has the northwest bias even in these types of events.

The NAM has been consistently crazy too. 18Z run will be out shortly.

[tron777]

MD is out now for a TOR Watch likely to be issued soon for ILL and Western IN:

https://www.spc.noaa.gov/products/md/md0357.html

[tron777]

NEW AFD from the boys for tonight:

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Incredible temperature gradient exists across the local area this
afternoon with a warm front still lingering across the far north.
Temperatures along and north of the front are still in the mid 40s.
Looking across the south reveals temperatures in the lower 80s. Cloud
cover is rapidly moving across the area within very strong
southwesterly low-level flow. Even with the cloud cover, growing
instability of 1000-2000 J/kg is moving northeastward into the area
as dewpoint temperatures climb into the lower 60s. This antecedent
atmosphere sets the stage for a very active severe weather evening
and overnight as a cold front approaches the area. Details below...

Wind Advisory: Ongoing wind gusts have peaked around 45 to 55 mph.
These wind gusts become less frequent and decrease in magnitude into
the late afternoon and evening ahead of the approaching severe
weather. Strong southerly flow will continue to feed warmer air and
rich moisture northward into the evening hours.

Severe Weather information by timing:

Late afternoon & early evening(~5pm-8pm): While model soundings
originally showed a capping inversion remaining in place through the
afternoon, there has been noticeable weakness in the cap, with some
high- resolution CAMs indicating some convective initiation ahead of
the primary event. Recent output from the HRRR suggests at least some
potential in supercells a few hours ahead of the line, but current
thinking is that this is overdone. Some showers are beginning to form
in southern Indiana, but with the lack of stronger surface based
forcing, these likely remain elevated within a region of warm air
advection. A slight chance of thunderstorms continues to be messaged
for this period.

Evening(~8pm-1am): Confidence is much higher that as height falls
occur across Illinois later this afternoon and early evening, an
eruption of thunderstorms will form far to the west of the local
area. As these cells merge and upscale, a mostly organized QLCS
quickly shifts eastward through Indiana and into western Ohio between
9pm and midnight. Upon approach to the area, additional cells form
ahead of the line, providing at least some chance for supercell storm
structures before the QLCS merges with them. Large curved hodographs
support the potential for strong tornadoes, specifically across
portions of eastern Indiana, western Ohio, and the greater tri-state
area. Even if cell mergers occur, strong tornadoes will be possible.
In addition to the tornado threat, a well established QLCS will
provide widespread damaging wind gusts of 60 mph, but also the
potential for more localized 70 to 80 mph wind gusts. The hail threat
will be greatest with any supercell structures or within the deepest
cores in the QLCS.

Late evening into the overnight(~1am-6am): As the QLCS continues
eastward at a rapid pace (60-70 mph), ALL hazards continue to be
expected as the line reaches Columbus southward toward the Ohio
River. The supercell threat has likely decreased, but the atmosphere
remains very favorable for tornadoes, with mesovortex tornadoes
quickly forming along the line. 70+ mph wind gusts also remain
possible within localized areas of the line. Hail threat is lower,
but quarter sized hail is still a possibility in the strongest cores
within the line.

Eventually, the line shifts entirely east and south of the local area
leaving in its wake, stratiform rain showers. By sunrise, the cold
front will be moving across the area. The location of greatest PoPs
is positioned across the south with any remnant rain associated with
the convection lingering across central Kentucky. Otherwise, much of
the area is likely dry heading into the short term.

Flash flooding: While confidence in flash flooding is low, if the
evolution of the QLCS or the development of thunderstorms ahead of
the line provide an opportunity for training or repetitive
thunderstorms, flash flooding would have the chance of forming where
this occurs. Otherwise, expectations at that the line quickly moves
across the local area, limiting heavy rain and better chance of flash
flooding to central Kentucky.

[tpweather]

MD is out now for a TOR Watch likely to be issued soon for ILL and Western IN:

https://www.spc.noaa.gov/products/md/md0357.html

I believe we will se the tornado watches go up for the local area probably between 5-7pm. Time period will probably be a 9pm-5a type of watch is my guess at the moment

[tron777]

ALERT: PDS TOR Watch issued for ILL, SE MO, SW IN, West KY, West TN, and N MS until midnight CDT.

https://www.spc.noaa.gov/products/watch/ww0098.html

[tpweather]

ALERT: PDS TOR Watch issued for ILL, SE MO, SW IN, West KY, West TN, and N MS until midnight CDT.

https://www.spc.noaa.gov/products/watch/ww0098.html

Les that was expected though these are rather rare each year this one no doubt fits the bill imo

[tpweather]

Les where the nam and hrrr models differ is later Thursday and I agree more with the hrrr output. Have not seen the latest nam but the noon time one was no doubt much different than the hrrr later on Thursday into early Friday

[tron777]

18Z NAM on the sounding is finally agreeing with the HRRR in terms of the sounding and the timing for tonight. I would agree Tim to go with the HRRR right now.

nam_2025040218_009_39.3--84.66.png

[tron777]

CAPE values of 2000 J/KG are developing now to our West / SW. We will see a bit more sunshine here soon and our CAPE values will respond accordingly.

[tpweather]

Hey Les and they still disagree about later Thursday as the nam is further north and west with the second round. Reason I like the hrrr is I believe the 1st wave overnight has no doubt went further southeast over the past 24 hours and I believe this tells me the round on Thursday has a better shot of being further south than the nam shows. Again once the first round settles in the morning sometimes this is when you would most likely see a change to the model runs. Further down the road still believe a break Friday and will watch to see if we get a decent rebound in sun and temps and if that happens that could lead to a wild last wave later Saturday as the main piece of energy moves through the area. Still going with 6-8 though always a little nervous giving out totals like that but I believe by Friday morning we are somewhere in the 4-5 inch range locally so a decent round Saturday would have us fall into the 6-8 inch range.

[tron777]

NEW Tornado Watch out for Central ILL and IND Land until 10pm CDT:

https://www.spc.noaa.gov/products/watch/ww0099.html

[tron777]

Hey Les and they still disagree about later Thursday as the nam is further north and west with the second round. Reason I like the hrrr is I believe the 1st wave overnight has no doubt went further southeast over the past 24 hours and I believe this tells me the round on Thursday has a better shot of being further south than the nam shows. Again once the first round settles in the morning sometimes this is when you would most likely see a change to the model runs. Further down the road still believe a break Friday and will watch to see if we get a decent rebound in sun and temps and if that happens that could lead to a wild last wave later Saturday as the main piece of energy moves through the area. Still going with 6-8 though always a little nervous giving out totals like that but I believe by Friday morning we are somewhere in the 4-5 inch range locally so a decent round Saturday would have us fall into the 6-8 inch range.

I agree with you Tim on everything you've said here. Great post!

[tron777]

VTP is now at a 6 or 7 in Central ILL and around a 5-6 in Central IN. For us, a 2 at this time.

[kywthrluvr]

Went out earlier to run some errands and came hope to find my empty Rumpke can had blown from the side of my house i to the street. The neighbor across the street has lost about a half dozen fence slats. That wind is no joke!

[tron777]

Storms continue to explode from ILL down into MS. The event is getting under way now.

[tron777]

MD issued for intense tornadoes becoming likely over West KY / TN down into N MS:

https://www.spc.noaa.gov/products/md/md0359.html

[tron777]

79 / 62 with a gust to 39 as of 5pm at CVG. Supercells continue to develop with l;arge hail and violent tornadoes over West TN and N MS. A few into SE ARK as well. The main line is producing damaging winds, hail and embedded tornadoes from ILL all the way down into AR. Gonna be a long night tonight!

[tron777]

20Z run of the HRRR. Sounding valid for 10pm tonight. Storms arrive by 10:30 or 11pm for the Metro.

hrrr_2025040220_007_39.0--84.73.png