Chris's Corner - Valentines Day Week 2022

What is the sref mean

12z euro is staying in the more south camp.

Edit: definitely north of its previous runs, but well south of the gfs.

Looks like a legitimate compromise.

The Euro feels like a nice compromise between multiple models. Still a long way to go with this system.

Are any of you looking at ground temps over the next 3 days with higher sun angles? It's gotta snow alot for a couple of inches. I don't see this being anything more than a advisory level just due to rush hour timing.

I would say the euro is a good split here. Maybe a 2-4 incher for the metro, more just nw.

Earlier this winter parts of Alabama were 80° and sunny and 24 hours later they had a few inches of snow on the ground.

Ground temps are very easily overcome with heavy snow

The neat thing about ice is that it cools the surface.

Here are some points I'm considering with my forecast for the next system.

This looks like a minor to moderate impact event in our area... and moderate to maybe major impact over northern Missouri... but it's borderline.
The 300mb jet structure argues for a somewhat further north placement closer to the GFS... but maybe not as far north.
The EURO (the southern range of the models) has a surface low that supports a position further north... closer to a southern adjusted GFS
The GFS has consistently been too amplified with open waves ejecting from the southwest this season. But once it has locked in... it has done very well. The NAM is not to be trusted with the low level cold air so I'm generally tossing its solution until it proves itself. It has been terrible with low level cold air on multiple occasstions this season.
The UK has also been trending northwest with the key features.
The ensemble means have been pretty consistently pinpointing a Sedalia to Quincy to Kankakee line as the center for the max snow. But the edges are likely too broad because of the averaging.
Using all of this... and the other standard forecast methods... I've come up with what you see below...





A week with two seasons! We start with the feel of spring... a little today and a lot tomorrow! But then the battle of seasons unfolds Wednesday into Thursday. This will start with rain and thunderstorms across the entire area late Wednesday into Wednesday night. Some of the rain will be heavy at times. Then, as the storm passes through... cold air will be pulled in from the north changing the rain to a winter mix and eventually snow.
As indicated by the map, there is a good chance much of the region will see at least a little winter precipitation. However, the location of the most impactful winter precipitation is still somewhat uncertain... as it usually is this far in advance. That being said, current indications are the greatest impact from winter weather will be just northwest of metro STL... lining up from central into northeastern Missouri (lookout Pike County!) We'll have more specirfics for you coming up later today and tonight.

My current thoughts...
The greatest potential for a moderate snowfall will be over our far northwest counties (grey shaded region)... this looks like 2+ inches will be possible of sleet and snow...so Pike County is in the cross hairs again! A sharp transition zone from several inches of snow... to almost no snow is likely on the southern side of this storm. It is likely what I have drawn is too broad... but I need to leave a little wiggle room with the storm still 3 days out.

In the Blue Zone... which includes the northwest half of metro STL... is where rain and thunderstorms are likely...with some heavy rain possible. This will eventually change to freezing rain and sleet before ending as a period of snow. There is some potential for light accumulations of ice and snow in the Blue Zone... but it is highly uncertain at this time.

The Pink Zone.... which includes the southeast half of metro STL... is where most of the precipitation will fall as rain...some of it heavy...along with some thunderstorms. During the day Thursday, the cold air looks to change this rain briefly to an icy mix and then snow or flurries. Accumulations will be hard to come by in this zone...but it's not impossible so I need to watch and better refine the detail here.

The Green Zone... this is basically a rain event in these areas...some of it in the form of thunderstorms with heavy rain. There may be a brief window Thursday afternoon for a quick mix... but it does not appear the kind of thing that would cause any impacts.

Not as important now, but all 3 globals look to have an even bigger system by next week too. Fun times ahead.

I still like 1-3” for northern metro with some freezing rain and sleet, then a 3-6” band north and west of the metro including Troy and Bowling green . 1” or less south of the metro. I think the Gfs will trend south some and the Euro will go north a little more

I believe the northern solutions and trends are the way to go. This will be a semi, but not classic cutter, as it only goes to the southern Great Lakes, not the heart or northern lakes like traditional cutters. Severe storms are a concern as far north as I-44/I-70 in Missouri and Illinois respectively.

18z nam is amped up big time.

Nearly a carbon copy of its 12z run.

Actually not much of a change, it just deepens to quickly pulling it north