March 2025 Weather Discussion

[tron777]

CVG picked up 0.22" from the overnight and early morning action.

[tron777]

Timing has moved up too per the 12Z NAM and HRRR. Both soundings are still frisky looking so the SPC's maps still look good to me. 5pm to 10pm looks to be the primary window for severe wx.

[tpweather]

Les you mentioned some sun in parts of Illinois and also thinner clouds in southern Indiana an western Kentucky. Getting the higher sun angle will probably allow at least some partial sun this afternoon. How many hours and will check on that around 1-2pm to get a better handle on the cloud situation. I agree the system has sped up some and this does get us into more of the prime time and storms may be a tad stronger further east as well

[tron777]

Les you mentioned some sun in parts of Illinois and also thinner clouds in southern Indiana an western Kentucky. Getting the higher sun angle will probably allow at least some partial sun this afternoon. How many hours and will check on that around 1-2pm to get a better handle on the cloud situation. I agree the system has sped up some and this does get us into more of the prime time and storms may be a tad stronger further east as well

The timing is great for severe wx, but the degree of instability is the only limiting or non limiting factor that I can see. Just too soon to tell as you mentioned.

[tron777]

A watch is likely to be issued for STL area and S ILL per MD from the SPC:

https://www.spc.noaa.gov/products/md/md0296.html

[tron777]

Not much change from the new Day 1 SPC outlook. See below discussion:

...Midwest/Ohio Valley to the Great Lakes...
Visible-satellite imagery shows cloud breaks to the immediate east
of the lead mid-level disturbance as a moist/warm conveyor (40-kt
southwesterly LLJ) maintains a fetch of seasonably rich moisture
into the region. Additional thinning cloud cover and heating
through the early to mid afternoon will lead to thunderstorms
developing and intensifying. A belt of 50-80 kt 500-mb flow will
overspread the destabilizing airmass and yield ample deep-layer
shear for organized convection.

The stronger early storms will favor supercell and banded linear
modes, with the supercells posing a threat for large to very large
hail (around 1.5-2.5 inch diameter) given the presence of steep
mid-level lapse rates and favorable deep-layer shear. Meridional
upper-level flow from I-70 northward will favor a quicker transition
to linear structures compared to farther south/southwest, where
hodographs will promote a longer window of opportunity for cellular
(discrete and clusters) storm modes. The tornado risk will be
greatest with quasi-discrete supercells (potentially a few strong
tornadoes) near and south of the OH River, but some tornado threat
will probably develop with a squall line as it matures through the
afternoon/evening. As storm coverage increases, multiple swaths of
numerous to potentially widespread severe/damaging winds appear
likely as one or more clusters moves quickly east-northeastward over
the OH Valley and southern Lower MI. The threat for damaging winds
and tornadoes should continue this evening into the overnight hours,
until convection outpaces the low-level moisture return and
eventually weakens over the upper OH Valley and central
Appalachians.

[tron777]

CAPE building to the west now.

sbcp_sf.gif

[tron777]

67 / 61 IMBY. If we can get some CAPE in here and I'm talking 1500-2000 J/KG range, then we should be in business for a couple rounds of severe wx this afternoon and evening. By the looks of the above map, that should be coming. I will continue to monitor the visible sat.

Update from the boys:

.NEAR TERM /THROUGH TONIGHT/...
Focus is on severe weather threat late this afternoon thru this
evening. Initial weak shortwave to continue tracking northeast thru
the area with ongoing showers decreasing from west to east as it
exits the region late morning into early afternoon.

Mid level shortwave to eject northeast across the Mid MS Valley and
into the Great Lakes today. At the surface, low pressure over
eastern IA to track northeast thru the Great LAkes and deepen today
and into southern Canada overnight. A southward trailing cold front
will sweep east across the area late tonight and early Monday.

Wind fields increase ahead of this system with surface dew points
increasing into the lower and even middle 60s in the warm sector.
This will result in the development of a corridor of moderate
instability ahead of the cold front. Convective development is
expected to our west during the early to mid afternoon hours, and
then spread quickly east. Favorable bulk shear will support organized
convection. Initially, discrete storms are expected to develop and
then quickly transition into a linear or multi-storm cluster mode.

There is some question to how far east discrete storms make it prior
to becoming more linear. The discrete storms(supercells) will have a
large hail and a strong tornado threat - with the highest potential
from the tri-state region and southwest. The threat for damaging
winds and possible embedded tornadoes will persist with the linear
feature due to the favorable low level shear thru the mid to late
evening hours. Eventually the convection will weaken as it tracks
across the Upper Ohio Valley and instability decreases overnight.

The most likely time frame for severe weather looks to begin as
early as 6 pm in Eastern Indiana/Western Ohio and North Central KY
with chances increasing thru 8 PM and continuing through about 11 PM
as the line moves across ILN/s forecast area into Central Ohio and
Northeast KY.

Highs today will reach into the lower 70s across most of the area
with mid 70s possible in the southeast before CAA evolves area-wide
toward daybreak Monday. Lows tonight range from the mid 40s northwest
to the upper 50s southeast.

[tron777]

TOR watch up for ILL and IN (All of it to our West) until 8pm EDT:

https://www.spc.noaa.gov/products/watch/ww0070.html

[tron777]

CINH is now gone over us and 500 J/kg is our CAPE for the Tri-state at this time. We shall see how much we can build from there in the time we have available. 4 hours give or take.

[MVWxObserver]

63 with a DP of 60 here in Greenville.

[Bgoney]

Brief Off and on appearance from the sun here. More of the same to our SW

IMG_3366.gif

[tron777]

Another watch likely to be issued over NE ILL, NW IN, and SW Lower Mich:

https://www.spc.noaa.gov/products/md/md0299.html

[tron777]

TOR Watch now for NE ILL, N IN and SW Lower Mich:

https://www.spc.noaa.gov/products/watch/ww0071.html

MD for another watch likely to be issued soon for N AR, S MO, Western TN, and Western KY:

https://www.spc.noaa.gov/products/md/md0300.html

[MVWxObserver]

63 with a DP of 60 here in Greenville.

Now 67 / DP of 61 and sunshine breaking through for destabilization.

[MVWxObserver]

----

[tpweather]

Good Afternoon and the weather is behaving the way it looked earlier today. Two lines of storms that will finally combine later this evening and move through rather quickly. Straight line winds the main problem but an isolated tornado is possible but with such a fast movement tornado's do have a harder time getting through act together. Rainfall with this evenings round will probably be near 1/2 inch for most but a storm lasting a tad longer can bringer a few higher totals. Then we get ready for the Wed-Sat period and that looks more interesting in many ways especially late Wed for severe weather and then the remainder of the week heavy heavy rains possible.

[MVWxObserver]

----

[MVWxObserver]

CVG got to 73, DAY 72 and CMH 70 today.

[MVWxObserver]

* Primary threats include...

Scattered damaging winds likely with isolated significant gusts to 75 mph possible

Isolated large hail events to 1 inch in diameter possible

A tornado or two possible

[tron777]

73 here earlier but had a shower come thru that dropped me back down to 69. Dew is 62. 1500 J/Kg is the CAPE we get to work with along with 40 knots of bulk shear and 150-200 for helicity. Lapse rates aren't the best so the hail threat should be low IMO. Wind is the highest threat for us followed by those brief QLCS spin up tornadoes. Winds to 70 mph possible in the strongest cells.

[tron777]

Individual cells are starting to fire now ahead of the main line. Those need to be watched for large hail and tornadoes if that can get going long enough before the main line comes in.

[tron777]

MD issued to our SW:

https://www.spc.noaa.gov/products/md/md0307.html

[tron777]

TOR Watch until 1am ET:

https://www.spc.noaa.gov/products/watch/ww0076.html

[tron777]

Tornado Warning
National Weather Service Indianapolis IN
708 PM EDT Sun Mar 30 2025

The National Weather Service in Indianapolis has issued a

* Tornado Warning for...
Southeastern Shelby County in central Indiana...
Southwestern Decatur County in central Indiana...
Eastern Brown County in south central Indiana...
Bartholomew County in central Indiana...

* Until 730 PM EDT.

* At 707 PM EDT, a severe thunderstorm capable of producing a tornado
was located 7 miles east of Nashville, or 9 miles west of Columbus,
moving east at 65 mph.

HAZARD...Tornado and damaging winds in excess of 70 mph.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.

* Locations impacted include...
Flat Rock, Newbern, Hartsville, Columbus, Geneva, Clifford, Gnaw
Bone, Grammer, Hope, Taylorsville, Elizabethtown, and Edinburgh.

This includes Interstate 65 between mile markers 63 and 79.