Absolute Vorticity

Good morning all... SPC has increased the severe potential Wed evening across the area. Best threat will be the further SW you are from Cincinnati. See outlook below.


We will be cold today as a warm front moves in tonight. A few showers possible but due to dry air, it's going to be tough to see much out of it. Temps will rise overnight and be in the L50s by this time tomorrow morning. During the day on Wed itself, esp in the afternoon, southerly winds will become quite gusty in the 40-50 mph range. LOU has a wind advisory out for their CWA. We should see some sunshine as well in the afternoon giving us some CAPE and temps in the mid to upper 70s! (80 possible for LOU)

Storms move in anytime around the 10pm to 1am range. Timing still need to be worked out. Storms will be strongest west of Cincinnati and weaken as they run out of CAPE as they move to the East the way it stands right now. Front passes thru around 5 or 6am Thurs morning then temps drop. there is the general set up and overview so let's now begin to discuss the finer details of this system.

I’m a little skeptical of the enhanced tornado risk down south. Most of the modeling wants to take things linear rather quickly versus discrete supercells. There will be tornadoes no doubt, but I’m not currently in agreement with their enhanced tornado probabilities. Up this way, marginal should work. Timing isn’t great for us but an isolated severe wind gust is possible.

The more sunshine we get tomorrow afternoon would allow for some stronger synoptic winds to mix down. We may see an extension of the wind advisory into ILN territory in later updates. Lovey day though temp-wise tomorrow! 80 is doable if we get some sun.

Trevor wrote: ↑Tue Mar 29, 2022 8:06 am The more sunshine we get tomorrow afternoon would allow for some stronger synoptic winds to mix down. We may see an extension of the wind advisory into ILN territory in later updates. Lovey day though temp-wise tomorrow! 80 is doable if we get some sun.

I agree Trev. We will have a strengthening LLJ, but CAPE is the ultimate question (like it is so many times) Some guidance is showing some decent CAPE and a few hours of sunshine. Also curious to see if the timing or arrival of the storms can speed up a bit. That would also help.

BG StormTalk! https://www.wave3.com/2022/03/29/stormt ... pdate-329/

Trevor wrote: ↑Tue Mar 29, 2022 8:04 am I’m a little skeptical of the enhanced tornado risk down south. Most of the modeling wants to take things linear rather quickly versus discrete supercells. There will be tornadoes no doubt, but I’m not currently in agreement with their enhanced tornado probabilities. Up this way, marginal should work. Timing isn’t great for us but an isolated severe wind gust is possible.

My nephew, his fiancee / her family, and friends of theirs are in the enhanced risk via Nashville i.e.

The moderate risk looks eerily much in the same places as was last week. Areas like Arabi, LA, suburb of New Orleans (Lower Ninth Ward) that were hit hard i.e.

Timing wise... the current look has the line approaching Cincinnati after 10pm and exiting our Eastern counties after 1am. Front passes around 6am Thurs or so and temps begin to fall after that. I like this idea for timing attm. If anything, once these storms get going, depending on how fast they move, that after 10pm may need to be sped up. For those wanting severe wx, you'd like to see the timing speed up for sure.

Moisture return is also in question. We'd like to see dews get to 60, but I think we'll fall short. 12Z NAM has the dew at 55 as the line approaches. Not quite juicy enough, but with the dynamics in play here, the marginal risk to me is good. Best chance for AV Country is our SW counties at this point fort isolated severe wx. Wind gusts to 60 mph is the primary hazard IMO. Better wind and TOR threats will be the further SW ones goes. 60 degree dews on the NAM are SW of Louisville. 12Z GFS is coming in now and it's fairly similar as well.

So that's my thinking. Isolated threat for strong winds and location wise, our SW counties have the best chance. Timing wise, 10pm to 1am

There's the wind advisory for everyone:

...WIND ADVISORY IN EFFECT FROM NOON WEDNESDAY TO 6 AM EDT
THURSDAY...

* WHAT...South winds 20 to 30 mph with gusts up to 50 mph
expected.

* WHERE...Portions of East Central and Southeast Indiana,
Northern Kentucky and Central, South Central, Southwest and
West Central Ohio.

* WHEN...From noon Wednesday to 6 AM EDT Thursday.

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

Wonderful AFD from the boys:

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
A busy 24 period of weather with concerns for fire weather /see
discussion below/, strong winds, severe storms, and anomalous
warmth.

Vigorous shortwave trough will deepen and become negatively
tilted during the day into the evening to our northwest across
Minnesota/Wisconsin. Initial sub-990mb surface cyclone over Iowa
on Wednesday morning will drift slowly eastward into Illinois
Wednesday afternoon, before accelerating and deepening more
quickly Wednesday night as the trough becomes negatively tilted.
MSLP likely to drop to around 977mb or so as the cyclone drifts
across northern lower Michigan on Wednesday night.

Main impacts from this dynamic/potent low pressure will be 1)
maintenance and further development of gradient winds and an
intense low level jet across the area Wednesday afternoon and
night 2) QLCS weakening as it enters the forecast area Wednesday
evening and 3) very warm temperatures with highs in the
mid/upper 70s.

Regarding the winds - forecast soundings indicate that initially
very dry sub-cloud layers will warm efficiently and allow some
portions of the low level jet across the Ohio Valley to begin
mixing to the surface. Especially after about 1 PM, winds/gusts
should steadily increase with steeper low level lapse rates and
warming temperatures despite a fair amount of clouds. CIPS
analogs to the pattern in place Wednesday evening suggests good
chances of wind gusts> 40 kts across Ohio/Indiana, and certainly
fits the pattern of a sub-980mb surface low crossing WI/MI.
These winds will not abate after sunset, and in fact, with the
trough becoming negatively tilted and the surface low deepening
more steadily Wednesday night, expect wind potential may
increase a bit after sunset, especially ahead of weakening QLCS
as it plows into the drier air and perhaps is enhanced by
isallobaric/evaporative cooling effects. Am somewhat concerned
that CAM solutions amp up the winds while ramping down the
simulated reflectivity, indicating perhaps some favorable
downdraft/evap cooling mechanisms may be in play as the
weakening convective system moves in. Would not be surprised if
there was a need for a few SVR thunderstorm warnings across the
southwest third of the CWA despite what appears to be very
little chance for charge separation /lightning/. Instability is
very meager if not nil, but SHERB parameters suggest low/mid
level lapse rates will be substantial enough to allow wind
damage anyway. Will watch this closely, and think SPC MRGL risk
is well placed and appropriate. Wind Advisory much of the
forecast area, may need to be expanded to all of the forecast
area in future forecasts, but wanted to hit the higher
confidence areas first which is eastern Indiana/western
Ohio/northern Kentucky.

Should see rain chances taper off quickly after about 2 AM, but
actual cold front will just be entering the forecast area in the
the hours before sunrise, and this feature may offer some gusty
low-topped showers of its own to contend with, although low
level moisture will have begun to scour out by then.

Good morning all... a few changes to talk about. First, we are in the 40s with SE winds at 10 to 15. Not too bad attm. Temps will soar to near 80 degrees this afternoon esp for Cincy on south. Winds will crank this afternoon per the wind advisory in effect from noon to 6am tomorrow morning. This is outside of any t-storm activity. T-storms will move into our area in that late evening to early overnight hour window. Still going with that 10pm to 1am window that I spoke of yesterday. If anything, models have slowed the arrival a touch so the severe threat may not be too bad as a result. Something to watch. Let's watch the storms firing up this afternoon to our west and south west, then let's see how quickly they actually move.

Still thinking the isolated severe threat is good esp for folks SW of Cincinnati. The more west you are and south, the better chance you have. Storms will weaken as they move thru our area so folks to the NE and out East, probably won't see much in the way of severe wx at all. Need to see the moisture return today and sunshine. We should see some sun this afternoon. The degree of moisture return is a limiting factor for sure. I still like strong winds as our primary hazard with a brief spin up possible. For hail, not a good set up for that.

From the boys:

Although a few light showers cannot be ruled out this morning
into the mid day hours, generally expect dry conditions today.

The main story will be the warm and breezy conditions along with
fire weather concerns. Fire weather concerns are talked about
below in the fire weather section of the AFD.

Strong WAA will allow for temperatures to climb into the 70s to
low 80s today. At this time expect Dayton, Columbus, and
Cincinnati all to stay below record values of 83, 82, and 83.

Winds will pick up today, especially for the afternoon hours.
Wind gusts upwards of 40 to 50 mph are expected. Current
placement of the wind advisory looks good as wind gusts will be
closer to the 40 mph range across central Ohio and into the
lower Scioto valley region.

There will be a decrease in cloud cover towards mid day and the
early afternoon hours before starting to increase again late in
the day.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Expect a line of showers to move through this evening and into
the overnight hours. Instability is limited and therefore the
probability of thunder is low. Due to this only have a slight
chance of thunder in the forecast. Of greater concern is the
potential for strong to severe winds both with this line and
near this time frame outside of the line. Continued current wind
advisory headlines. While eastern portions of the region look
like the winds will be slightly lower, there is still some
potential that the current wind advisory will need to be
extended further east for the tonight time frame. The main
severe threat does look to be damaging winds given strong low
level wind fields.

Late Wednesday night into Thursday a cold front will move
through and bring additional showers. Due to this front, the
coolest temperatures will be across western portions of the
region on Thursday.

Current look at the dews... CVG is around 30 right now which is better then the teens we saw yesterday.

BG StormTalk! https://www.wave3.com/2022/03/30/stormt ... pdate-330/

Warm front has passed and CVG has shot up to 61.

Biggest changes to the new SPC Outlook is to trim the marginal risk back North of Cincinnati and the slight risk got bumped NE a tad of LOU. So for folks N and E this is good news! Synoptic winds are still going to be roaring however for everyone. Gusts between 40-50 are likely this afternoon and overnight. If you get a heavy shower this evening then 60+ mph likely in gusts. Best chance for that is SW of Cincinnati as previously mentioned.

12Z HRRR has the line coming in with isolated damaging winds around 11-12pm tonight. A brief spin up possible. Best shot on this model to me looks to be from about Cincy on south.

12Z NAM is similar to the timing and is better from about CVG on south for the most intense part of the line in our local area.

Models continue to show 850 MB winds of 80 knots so if we can get say just half of that or more mixing down the surface, there's going to be isolated problems out there. Winds are beginning to get a little gusty around here to about 25 mph attm, maybe 30. That's just going to increase as the afternoon wears on.

68 / 49 as of 11am at CVG. I don't think we'll hit 60 for a dew, but the mid 50s are possible.

72 / 50 now as of 12pm. Can hear the wind starting to roar now. CVG gusting to 35 already.

Currently 63 and a gust of 23 mph here in G'ville. Progged to top out at around 75. DAY going for 77.

I am at 71 / 52 currently imby with wind and partly sunny skies. Visible looks decent for continued off and on sun so pushing 80 here is absolutely possible. 83 is the record at CVG and I think we won't get quite that warm.

75 at CVG now, dew of 48. I could see dews lowering as dry air aloft mixes down to the surface. A temp. thing then it'll rise again once the front gets closer and deeper moisture begins to pool. With that stated, drier air would allow for the airmass to warm more. So 80 again should be pretty easy.

TOR Watch until 9pm our time for the Lower TN and MS Valley region.

https://www.spc.noaa.gov/products/watch/ww0077.html

55+ degree dews are over all of S ILL extreme West KY and the very western edge of IN at this time. Weak CAPE of 100 J/kg also exists in this area. Elsewhere it is dry air city and will remains so until this evening for us. Today would be an awesome day to be outside if it wasn't for the wind lol

A new Severe weather watch is likely to be issued to our SW soon. An 80% chance of a watch issuance for the area I described above:

https://www.spc.noaa.gov/products/md/md0355.html

80 at CVG now... can we break a record I wonder due to the drop in dewpoints? Dew has fallen to 41! This is allowing the stronger winds to mix down to the surface,. CVG now gusting to 43 mph. 50+ probably not far away...

Quick afternoon update from the boys:

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Gist of going forecast in great shape. After perusing latest
forecast soundings, have enough concern to add a tier of
counties to the Wind Advisory including the CMH area. The 30.12Z
sounding from ILN shows impressive warming/inversion aloft, that
will take some time to erode and allow access to axis of low
level jet which will bring gust potential to 40-45 mph during
the afternoon, especially west of I-71 and mostly centered after
2 PM. A little slower than previously anticipated. Temperatures
look well trended, especially considering rate of rise this
morning. Satellite indicates a fair amount of sunshine
especially southeast 1/2 of forecast area which will drive highs
close to 80F and promote fire weather concerns /discussion
below/. A few sprinkles possible here and there this morning,
but these will trend downward this afternoon as big surge of mid
level drying comes in this afternoon as shortwave digs and
becomes negatively tilted to our west. Most concern for wind
impacts area wide will be after sunset. Concern for fire weather
impacts will be before sunset - in the 2PM-7PM timeframe.