RCNYILWX

The new and improved Kuchera output from WxBell.

Finally, took a while. I think one of our forecasters had emailed them as well about that issue. We have a pro account for the whole office with them. Sent from my SM-G965U using Tapatalk

Maybe WxBell finally fixed their Kuchera algorithm randomly on a Sunday? Sent from my SM-G965U using Tapatalk

Ensemble mean QPF for 18z GEFS, a tick up from 12z. 0.5"+ LE for downtown Chicago is impressive for an ensemble mean. And IND is looking money, as well as Detroit area. Sent from my SM-G965U using Tapatalk

Re. those regional maps, there's latency issues on NDFD, so if one office published their grids later than the data grab time for that particular map, it'll use the previous update. Would wait until about 4pm CST and 5pm EST to be sure those are the latest maps from each office. Sent from my SM-G965U using Tapatalk

Okay I'm gonna do a little bit of armchair meteorology here. This is while acknowledging such a big change from one forecast package to the next is a big deal and we try not to have too much of a windshield wiper effect in our products. That all said, I'm surprised DuPage and all of Will County were not included in the warning, as well as Livingston. For all three, there's valid meteorological and impact reasons why they should have been included. In addition, the hazard map looks cleaner with them in. DuPage County, to be even a bit more specific, the eastern half of the county or so typically does well in northeast flow lake effect/enhancement. Also ORD actually partially goes into far northeast DuPage. If we're saying that northern and central Cook can expect 8-12" and locally higher, you can be sure those warning type impacts won't stop at the county line, barring a major subsequent shift back southeast. From my experience, parts of northern Will also do well in northeast flow LE. Finally, there's multi-model support for 6+ amounts in southeast half of Livingston. Sent from my SM-G965U using Tapatalk

The NAM giveth and taketh lol Part of what makes it tough is it's hard to pin down when that model is not going to be unstable for this area. Running with roughly what ensemble means show and added detail for lake enhancement probably the way to go for QPF and snow amounts. Figure a 15-20:1 ratio on average and greater than that for lake enhancement.

The 18z HRRR is legit save worthy for downtown Chicago. And also very solid for the metro. Which represents a bump from the 12z run. Sent from my SM-G965U using Tapatalk

That's not really an accurate statement. There's multi model support for higher than 1-2" amounts, especially for eastern half of the county. 1-3" looks reasonable for RFD. Sent from my SM-G965U using Tapatalk

Always fun to take the time to post on here along with [mention=1610]purduewx80[/mention] and any other NWS mets that post here and on other subs, and see others saying they'd have no problem defunding the NWS.

The 06z EPS as you'd expect also notably bumped NW vs 00z run, which itself was a noteworthy jump from the 18z run. Can a trend gif be created on WxBell? Sent from my SM-G965U using Tapatalk

I think ultimately it shouldn't have been too surprising that this could come back northwest when you have a strong short-wave ejecting out of the southern Plains and already good eastern ridging out ahead. The TPV lobe exiting east quicker and the short-wave coming in even stronger and negatively tilted looks like it's sealing the deal.

You have wiggle room because of the excellent antecedent air mass. Never want to say never in weather but I think your area will be okay. Ohio is more of an issue with east and southward extent.

Yes, see new NAM rolling out haha Edit: Warning amounts for much of the metro through 09z Tuesday and still snowing.

From my coworker at LOT on shift today: "Yeah, this really got interesting. 0.5" QPF contour comes into our CWA now, already chatting with neighbors we'll have to increase totals perhaps by a factor of 2. Also, NBM gives Chicago a foot of LES. If the NBM is doing that, we're in trouble. Could envision having to issue a warning for a good chunk of the area."

In addition to the changes with weakening confluence and strengthening eastern ridging, doesn't hurt that the 500 mb shortwave is trending stronger and more neutrally to close to negatively tilted. This also feeds back to the background ridging out ahead of the system, with an additional bump in height rises.

Thankfully there's good support now from all the non-GFS op models. It may not be done trending either. Distinct trend to weaken the confluence from the departing PV lobe due to an earlier escape east and strengthening ridging out ahead of the system.

Additionally, QPF, sleet and freezing rain output.

Here's a better zoom for the 06z Euro, Kuchera output and 10:1 for reference.

If the liquid equivalent of 0.6" for that run is close, absolutely possible to get double digits. Averaging a 17:1 ratio would get it done at that liquid equivalent. The WxBell Kuchera algorithm has an average around 23:1 which is very likely still overdone for an average. However, in these events, within mesoscale banding if the thermal profile is favorable for a deep DGZ, and strong lift is well aligned with the DGZ you can get at least temporary >20:1 ratios.

They still look overdone, but in this air mass have a chance to be closer to correct in spots. Unfortunately Pivotal Weather doesn't have the 06z run to make a direct comparison. It largely comes down to how deep the DGZ is, how strong the omega is, and how well aligned it is with the DGZ regarding ratios. Having the cold air mass certainly helps when the lift is strong and well aligned with the DGZ.

QPF total got messed up so trying again Sent from my SM-G965U using Tapatalk

I'll post shortly, will post the total QPF, Kuchera and 10:1 for reference. Edit: Here you go

Euro bumpin again. If the guidance trends are to be believed, our amounts aside from LES going to need to be adjusted upward and headlines are going to need to be adjusted northwest today.

NSSL WRF is almost 18" for downtown Chicago by 00z Tuesday and still ripping at the end of the run. Sent from my SM-G965U using Tapatalk