Absolute Vorticity

Clouds are quite stubborn to leave here - you would think being in a dome that deters rain, that it would deter clouds as well. Nah! LOL

The SW corner of Ohio is destabilizing like I am over here in NKY but the northern extinct of this is going to have its limits. Mike... going to be close for you guys in our I-70 Crew zone.

There's the TOR watch box now issued for MO ahead of the MCV:

https://www.spc.noaa.gov/products/watch/ww0243.html

EDITED Post to correct link and type-o's. (As usual)

2500 J/KG CAPE over NKY now... Ohio... catch up!! Did you guys see the Lifted indices (LI's) -10 from West KY into Middle TN? Googly Moogly! I was content with the -3 to -4 over my hood.

Quick 12Z GFS update for this weekend... looking hot and humid with temps in the U80s to L90s for Sat. Best chance for storms will be NW counties during the afternoon and evening. Isolated for the rest of us. Sunday is the day for most of us to get wet with the front not clearing our KY counties S of the River until early evening.

ALERT - Watch likely!


Mesoscale Discussion 0829
NWS Storm Prediction Center Norman OK
0118 PM CDT Thu May 19 2022

Areas affected...southern Indiana into Kentucky

Concerning...Severe potential...Watch likely

Valid 191818Z - 192045Z

Probability of Watch Issuance...80 percent

SUMMARY...Clusters of storms producing large hail and sporadic wind
damage are expected to persist for several more hours.

DISCUSSION...Visible imagery shows a substantial CU field across TN
and KY, with a surge of higher dewpoints northward. Storms have
erupted along this effective front over southern IN which also lies
within the 850 theta-e advection zone. Given continued heating and
the persistent diffuse moist advection zone, addition clusters of
storms may form east or southeastward into KY, with hail and
localized wind damage. The ongoing IN cluster may effectively
translate eastward, and additional isolated storms may develop to
its south over central KY.

FYI - 70 mph wind tags with those storms between Evansville and Louisville

New Svr TS Watch until 8:00 for southern Indiana and central Kentucky including Louisville

Sorry for the rambling here LOL Anyone notice the very latest HRRR has absolutely nothing in Indiana for now? Meanwhile we have 5 SVR (2 considerable) and 1 TOR warnings there. Gonna be an interesting evening...

T-storm watch out now just to the W and SW of us.

https://www.spc.noaa.gov/products/watch/ww0244.html

Hey hey finally seeing sunshine now!

You can see where the warm front is easily by looking at visible sat where the t-storm towers are developing. Going to eye ball it and say from a ST. Louis to between EVV and LOU thru South Central KY still a ways south of the I-64 corridor. Movement is to the NE towards us for the warm front itself. Individual cells also moving ENE. 80 degrees imby now with a dew of 69.

Current Mesoanylsis as of 3pm: 3500 J/KG of CAPE now right over the Metro! The atmosphere is becoming like a powder keg now, just waiting on the trigger to arrive. LI's now at -5. Steeper lapse rates that I mentioned to our SW earlier are now here! Supercell comp index now at a 4.

So may not take long for us Dayton folk to catch up. Temp up to 75 and mesoanalysis shows almost 3000 J/kg SBCAPE even here now. Our Supercell composite about a 2 or 3.

12Z Euro dumps an inch of rain overnight from the t-storm activity we are watching. This is for CVG! Not much else until Sunday afternoon with the front.

For next week.... the Tues night and esp Wed daytime period is looking interesting for severe wx. Stay tuned! Wed has been showing up for a while now.

So guys... to summarize... We are watching this evening... then again Sat late for NW counties. Sun afternoon for the rest of us for some more rain then finally what I just mentioned for the middle of next week. Busy enough for you? Gonna be tough for many folks to get a mowing in next week.

Whether we get hit or not... I will already give you PROPS Trev because the warm front is already more active then I thought it was going to be anyway so I would have most likely busted whether you posted today or not.

I think that the storms are going to be arriving faster then that 8-9pm window. Any takers on an earlier arrival time like maybe 6-7 pm? AFD from the boys thru tomorrow:

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A warm front trailing southeast from the low located near
Minnesota lifts north through the Ohio Valley, bringing showers
and storms this evening. In addition, a MCV located in the warm
sector of the low is moving northeastward into the tri-state
area, forcing convection out in front of its center.

Dew points have trended higher (69 degrees F at CVG) as moisture
surges northeastward with the front, ample instability (SBCAPE
on the order of 2000-3000 J/kg) is present, and a nose of a low
level jet moves into the tri-state this evening. This, combined
with the advancing warm frontal boundary, will aid in producing
some strong to severe storms this evening into the overnight
hours, particularly in northeast Indiana, northern Kentucky, and
southwestern Ohio. The largest threat with these storms
continues to be hail and damaging winds, however, an isolated
tornado cannot be ruled out as surface flow backs ahead of the
warm front.


&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
By Friday morning, pcpn moves out of the area. The center of the low
pressure system will have shifted eastward toward the Wisconsin
area, placing our CWA inside of a potent warm sector. Ample
southerly flow and clear skies will aid temperatures to increase
into the upper 80s/low 90s throughout the day. In fact, we will be
within a degree or two of record breaking criteria at the Big 3
Climate sites (records: KDAY 91, KCMH 91, KCVG 92).
With that being said, post- frontal breezy conditions prevail
throughout the day, with S/SWly winds around 20 mph, gusting up
to 35 mph, especially in prone areas in west central Ohio.

Winds die down slightly Friday evening and overnight temperatures
cool to the low 70s/ upper 60s across the area.

That bow in Missouri looking quite impressive. Lines up well with the new Enhanced and Slight risks expansions in the new day1 outlook.

I think we could definitely see some cells along the warm front prior to 8-9 pm but I think the main show (if it survives here) would be around or after midnight IMO.

Mike and really everyone... Just to limit any potential confusion coming from me... I was talking about the arrival time of the cells immediately to our SW that we're watching for first impacts. We will all be awake and alert for those and it should still be light out too.

Cautiously optimistic, not sold on severe just yet for cvgland. Would at least love to get a heavy rain to get rid of the last of the pollen hanging around.

T-storm watch boxes are out for folks West of us and S of us at this time.

Cells seem to be losing steam when they try and push N of LOU. However, check out the AFD from the LOU office. We probably need to wait a few more hours before we know for sure how things will trend for us.

Synopsis...Strong storms capable of producing severe hail and
damaging winds are already ongoing along the lifting surface
boundary previously located in the Tennessee Valley. Moreover, an
MCV moving later on through south-central Indiana might trigger
another round of severe storms as well as isolated flash flooding
instances. SPC has highlighted an Enhanced risk of severe weather
for northwestern Kentucky and southern Indiana due to the increasing
threat of damaging winds and hail. Also, a Severe Thunderstorm Watch
(#244) is in effect until 8 pm EDT for southern Indiana and most of
the central Kentucky counties west of I-75 to account for the
potential of re-strengthening convection during the late afternoon
and early evening.

This Afternoon and Tonight...A theta-e advection regime has
effectively initialized convection along a line extending NW-SE from
southern Indiana to south-central Kentucky. Initially, the main
severe threat with this line would be damaging winds and large hail,
although a brief tornado cannot be ruled given streamwise vorticity
ingestion due to boundary collision processes. SPC mesoanalysis
reveals effective bulk shear around 30 kts and slightly oblique to
the forcing boundary, which initially favors organized multicellular
storms or supercells. That has been the radar trends during the past
couple of hours. Nonetheless, anvil-level flow and the closed
distance between developing storms indicate that cold pool
interaction will be favored once storms are in the mature phase.
Therefore, storm mergers will be expected during the foreseeable
future. Seems to me that the mean wind is modestly low for upscale
growth at this time.
Persistent moisture advection and clearing behind the current
convective line hint at a quick instability recovery for convective
initiation during the late afternoon and early evening. Enhanced low-
level flow attendant to the MCV circulation and mass response might
be the forcing mechanism for further storm coverage. It is noted
that effective SRH and 0-1 km shear will eventually augment and
overlap with the potential second storm episode. Further
confirmation of a tornado risk is provided by the composites SCP and
STP indexes, both of which increase after 21 Z. Therefore, there is
a conditional risk of tornadoes provided that storms kick off during
the aforementioned time frame. On the other hand, flash flooding
should be closely monitored due to the heavy rain rates already
evidenced on radar and the expected environmental ingredients. The
most vulnerable zones will be the low-lying areas or urban settings
with poor drainage as well as the ones that received rainfall
yesterday and, therefore, the 1-hr (3-hr) FFG is already low.

Friday...Dry air and low-level subsidence will keep precipitation
chances out of the forecast at the start of the weekend. The
combination of solar heating and warm air advection related to deep
southwesterly flow will allow temperatures to soar, probably
breaking some records (see Climate section below). Finally, a
healthy LLJ in combination with steepening near-surface lapse rates
will ensure gusty winds around 30 kts during the afternoon hours.

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