Absolute Vorticity

tron777 wrote: ↑Thu Jan 19, 2023 8:57 am

cloudy72 wrote: ↑Thu Jan 19, 2023 8:53 am SPC out with an enhanced risk for DAY-CMH corridor for this afternoon.

Rainfall here so far 0.77"

Wow! This could get interesting especially for you all around the I-70 Corridor. Already seeing some sunshine now and visible satellite looks good for a few hours worth. That'll only get the wind cranking as the higher winds aloft begin to mix down.

I think this could bring Trev out of his den for a bit today

Bgoney wrote: ↑Thu Jan 19, 2023 9:06 am

tron777 wrote: ↑Thu Jan 19, 2023 8:57 am

cloudy72 wrote: ↑Thu Jan 19, 2023 8:53 am SPC out with an enhanced risk for DAY-CMH corridor for this afternoon.

Rainfall here so far 0.77"

Wow! This could get interesting especially for you all around the I-70 Corridor. Already seeing some sunshine now and visible satellite looks good for a few hours worth. That'll only get the wind cranking as the higher winds aloft begin to mix down.

I think this could bring Trev out of his den for a bit today

I'm honestly shocked that he hasn't posted this week with the mild weather we've been experiencing. This pattern has been right up his alley.

Wonderful outside and feels and looks like a mid-March day. Nice video by Brian and mentions everything we have talked about on this forum. The Sunday system is one we need to see if we get a phase and if we don't which is possible precip totals of rain or snow will be even lighter for some folks. Bgoney talked about how the Euro moved north and that is true though the track is still not bad and then we need to see where an upper low will be placed. The biggest problem still is the cold air. We will have some but not polar in nature though I believe late next week we see some cold that will give us a nice shot of arctic air. These kind of systems over the next week are nice when you already have snow of the ground as it keeps colder air locked in and then you get a nice southwest wind which brings moisture but not quite the warmth you see from a southeast wind. The problem is that snow cover by next Tuesday looks very unlikely even if it snows on Sunday the changeover to rain is likely and with temps near 32 even if it stays all snow it will melt by Tuesday and of course south of here very little chance of snow. Tons of model watching over the next few days and hopefully by Saturday the models have narrowed down the system for late Tuesday and Wednesday and no doubt the best shot of snow since just before Christmas.

12Z NAM shows a very weak, unorganized system for Sunday. Very little precip until it finally gets its act together over PA. 12Z RGEM has a more organized system so you get that thumping of snow Sunday morning before going over to rain from the Tri-state on south. I-70 Crew would stay all snow for the entire event and would be able to pick up a few slushy inches out of the deal.

have to like what the models are showing for next week. several storms one after the other. im just concerned about the cold I would like to see a stronger high pressure for the storms to feed off of then I would feel better about snow chances

Are you kidding me?

Full sunshine here. Feels balmy. The calm before the storm.

airwolf76 wrote: ↑Thu Jan 19, 2023 10:29 am have to like what the models are showing for next week. several storms one after the other. im just concerned about the cold I would like to see a stronger high pressure for the storms to feed off of then I would feel better about snow chances

Totally agree! So we've got to rely on the proper phasing unfortunately to make it happen which is always difficult in the Ohio Valley especially. The pattern looks better for cold behind that system so hopefully we can cash in then if we fail on Tues night and Wed's system.

Bgoney wrote: ↑Thu Jan 19, 2023 10:30 am Are you kidding me?

Definitely liking the hail risk too. Freezing levels down to 7,000-8,000 feet now.

young pup wrote: ↑Thu Jan 19, 2023 10:31 am Full sunshine here. Feels balmy. The calm before the storm.

It is gorgeous right now for sure! I plan on going outside for a bit on my lunch break.

A very nice update from the boys as of 9:08 am:

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Showers have moved east and clouds are decreasing in a dry slot
wrapping around complex low pressure, allowing sunshine to
occur for a period into the early afternoon hours. Our attention
then turns to low pressure and another cold front to our west.
As low pressure moves northeast toward the western Great Lakes,
another cold front attendant to this low is forecast to sweep
through the area later this afternoon into this evening. Despite
low pwats of 0.50 to 0.60 inches, models continue to show that
the atmosphere will destabilize quickly this afternoon as the
boundary layer warms and mid level lapse rates start to steepen.
This developing instability (about 500 to 800 J/kg MLCAPE) will
interact with the advancing front. Increasing speed convergence
in the low levels and upper level lift from a vort lobe
rotating around the parent mid level low should result in a
developing line of showers and embedded thunderstorms as seen by
the various CAMs. This activity will be associated with
increasing winds aloft along and behind the front due to a
developing pressure rise/fall couplet. These winds, along with
steepening low level lapse rates and relatively dry dewpoints
(mid 40s) will pose a strong to severe wind threat across our
region. This has been highlighted in the latest SPC SWODY1
product, which now shows enhanced risk from Dayton to Marysville
and Columbus. Given strong speed shear, some rotation is
possible, but there seems to be a lack of direction shear in the
low levels so hopefully this will keep the tornado threat on
the low side. We will certainly continue to watch observational
and model trends should this change. Some high resolution models
(HRRR in particular), indicate that there could be a 2 perhaps
3 hour period of wind advisory type wind gusts (around 40 knots)
behind the front/outside of the convective line. Given the
uncertainty of how long this window will be, will issue an SPS
for the entire region to highlight this threat and in
collaboration with surrounding WFOs. For now, the current Wind
Advisory for parts of the Tri-State will remain, but will
highlight the period of stronger winds along and behind the cold
front. Highs today will range from the mid 50s northwest to the
lower 60s southeast, which are well above normal for this time
of the year. Record highs, however, should not be in jeopardy
(upper 60s to the lower 70s).

tron777 wrote: ↑Thu Jan 19, 2023 10:49 am

young pup wrote: ↑Thu Jan 19, 2023 10:31 am Full sunshine here. Feels balmy. The calm before the storm.

It is gorgeous right now for sure! I plan on going outside for a bit on my lunch break.

Been outside here. Getting some wind gusts to 20 to 25 mph here????

12Z GFS to me for Sunday also looks unorganized with some light snow. Text data shows thermals should remain cold enough on this run for mostly frozen precip but it is light. Surface temps are warm too. So it's a case of heavy precip rates would be snow. If it is light then it's rain / drizzle.

Then for Tues night and Wed... the GFS is coming in with a more wound up system. A 987 MB low over Evansville, IN does us no good. You want that over SE KY or WV for a snow storm here.

young pup wrote: ↑Thu Jan 19, 2023 11:10 am

tron777 wrote: ↑Thu Jan 19, 2023 10:49 am

young pup wrote: ↑Thu Jan 19, 2023 10:31 am Full sunshine here. Feels balmy. The calm before the storm.

It is gorgeous right now for sure! I plan on going outside for a bit on my lunch break.

Been outside here. Getting some wind gusts to 20 to 25 mph here????

Same thing here. Not too bad wind wise yet, but it'll pick up as the front gets closer to us this afternoon. Once the leading edge of the upper trough comes in it'll ramp up quickly. The visible satellite pic below shows that it is almost ready to enter Western IN and KY so we've got a few hours yet.

Freezing levels in ILL ahead of the front are like 2000-3000 feet so they will continue to lower over us to that level also. The storms that do pop (in the stronger cells) will contain some hail. Small hail at the very least should be common along with strong winds and an isolated tornado. Again, best threat for more organized convection is north, but the threat is still there even for us in the Cincy area too. Certainly worth watching the radar from about 2-3pm on.

12Z Canadian for Sunday continues the disorganized theme and we get a short period of snow / rain for the area. So far, I'm glad that I did not start a thread for this system. Then for next week's storm, the Canadian is pretty much like the GFS. Might be tracking rain and storms again should this solution be correct. We'll see. The Euro for this Sunday so far was the leader in showing the weaker, more southerly solution that pretty much all models are now agreeing upon. Now yes, the 0Z Euro did bump NW from it's prior solution but it is still more SE then the rest of the guidance. We'll just have to wait and see if the Euro is leading the pack for next week or will it continue to come NW and rain on us? Ensemble guidance from the overnight runs (GEFS and EPS) also favored the more northerly track.

NEW Update from the SPC now expands the marginal risk down towards LOU. Slight risk pretty much now to CVG and the enhanced risk area covers more of our OH counties.

Lapse rates are starting to increase.


Wind shear is ridiculous!


And finally... 100 J/kg of SB CAPE is starting to develop SW of us over Southern IN.

ILN is sending up an extra balloon at 2PM. Concerned about the risk, since we’ve never had an enhanced risk in January before.

Impressive wording from spc



THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS WESTERN AND CENTRAL OHIO
### SUMMARY

Low-topped thunderstorms are expected to develop over eastern Indiana and move rapidly east across Ohio this afternoon into early evening. Scattered severe wind gusts from 60-80 mph are most likely between 3 to 7 PM EST in western to central Ohio.

Eastern IN and OH
A potent mid-level vorticity maximum over IL, embedded within the broader central CONUS trough, will eject east into OH through this evening. This feature will aid in sharpening an associated surface cold front that will rapidly progress east. Low-topped thunderstorms are expected to initiate across eastern IN towards early to mid-afternoon in a broken arc along the front. Within the exit region of an intense mid-level jet, this convection is expected to race east across OH through the afternoon. While SBCAPE will likely be meager, holding at or below 500 J/kg, nearly full insolation across the Lower to Middle OH Valley will yield steep 0-3 km lapse rates. This should support downward momentum transport of 50+ kt low-level winds as convection matures. Some 12Z HREF members (HRW-ARW, HRRR, and NAM-Nest) suggest boundary-layer max winds may reach 65-70 kts within rear inflow, supporting peak surface wind gusts across western to central OH. The arcing convective band will weaken after sunset as surface-based instability dwindles, but strong gusts may persist until convection dissipates in the western to central PA vicinity

Bgoney wrote: ↑Thu Jan 19, 2023 11:46 am Impressive wording from spc



THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS WESTERN AND CENTRAL OHIO
### SUMMARY

Low-topped thunderstorms are expected to develop over eastern Indiana and move rapidly east across Ohio this afternoon into early evening. Scattered severe wind gusts from 60-80 mph are most likely between 3 to 7 PM EST in western to central Ohio.

Eastern IN and OH
A potent mid-level vorticity maximum over IL, embedded within the broader central CONUS trough, will eject east into OH through this evening. This feature will aid in sharpening an associated surface cold front that will rapidly progress east. Low-topped thunderstorms are expected to initiate across eastern IN towards early to mid-afternoon in a broken arc along the front. Within the exit region of an intense mid-level jet, this convection is expected to race east across OH through the afternoon. While SBCAPE will likely be meager, holding at or below 500 J/kg, nearly full insolation across the Lower to Middle OH Valley will yield steep 0-3 km lapse rates. This should support downward momentum transport of 50+ kt low-level winds as convection matures. Some 12Z HREF members (HRW-ARW, HRRR, and NAM-Nest) suggest boundary-layer max winds may reach 65-70 kts within rear inflow, supporting peak surface wind gusts across western to central OH. The arcing convective band will weaken after sunset as surface-based instability dwindles, but strong gusts may persist until convection dissipates in the western to central PA vicinity

Wow. Better move any vehicles from under trees at those speeds. Guess I better go for a walk now too.

Daddy likey.

Trevor wrote: ↑Thu Jan 19, 2023 11:59 amDaddy likey.

There you go Bgoney! Trev finally came out to play!

Trevor wrote: ↑Thu Jan 19, 2023 11:59 amDaddy likey.

We all know he just can’t wait for the cold front to move in…