Joe’s Weather Blog: This is going to be a strange weather week (SUN-1/8)

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I have a feeling this may be a rather interesting week of forecasting. Temperatures will be going up at unusual times…perhaps dropping at unusual times and then there is the whole issue of what happens at the end of the week which won’t resolve itself for a few more days (at least). Hang on…it may be a bumpy ride.

Forecast:

Tonight: Fair skies and chilly but overall not as cold as it has been over the past few mornings…lows around 20°

Monday: Variable clouds and a bit more seasonable with highs approaching 40°. Low clouds will move into the region later in the day from the south and some drizzle/mist is possible at night

Tuesday: variable clouds with the risk of some scattered rain showers. Temperatures in the morning will be well into the 30s and highs should be well into the 40s locally before dropping off towards the later afternoon into the 30s

Discussion:

Last night was another very challenging forecast. Temperatures were dropping…but the winds were switching and increasing from the SE…skies were clear but clouds were going to move into the region reversing the dropping temperatures and allowing the readings to start going back up. My forecast was 6°. The low was 6°. When daybreak came though temperatures were already 14°. A weird night.

That, in a nutshell, may describe the upcoming week of temperature forecasting…at some point the arctic air will win out…it almost always does during this time of the year. Remember we’ve written numerous times in the last couple of weeks that until that arctic air is scoured out of SW Canada…which I think may happen in another 7-10 days or so…it’s tough for us to have sustained mildness.

Today temperatures have been affected by the remaining snow on the ground and all the clouds that have lurked since early this morning when they arrived. This afternoon however we’re starting to brighten up and we should enjoy more sunshine for the rest of the day. As of 1PM we’re at 26° at KCI…we should at least get to 30° and some will do better. feels chillier though because of the SSE winds at 10-15 mph.

Those winds will continue to switch more towards the south on Monday. This will keep temperatures up a bit more tonight (more seasonable) and also allow a better recovery tomorrow as we start really melting the snow. We should have a mixture of sun and clouds so temperatures should recover to around 40° or so I hope.

Then Monday afternoon some moisture will surge this way from the south. This will be in the form of a low overcast and it will overtake the area later Monday into Monday evening. some drizzle is possible with this surge moving through the area into early Tuesday. This moisture will be about 3000′-4000′ thick. It will then push out towards Tuesday afternoon. With the low clouds in place on Monday night…temperatures will not drop and may actually continue to rise a degree or two.

Then on Tuesday we should see a weak front push through…this will shunt that low level moisture towards the east of here as the day moves along. A mix of clouds and sunshine should allow us to recover into the mid 40s or so and after a brief drop in the Tuesday evening temperatures a return to a more southerly wind flow will again allow temperatures to hold steady or even go up overnight Tuesday into Wednesday AM. Temperatures just above the surface will be near 50° WED AM…so we should get into the 50s on Wednesday before another somewhat stronger front comes in WED PM and sends temperatures downwards in the mid-late afternoon it appears.

Like I said…a weird weather week.

This Wednesday PM front will eventually meander down towards the Ozarks and the I-44 corridor (if not farther southwards. It will end up being the key potentially to the weekend forecast.

As I’ve written about over the last couple of blogs…let’s keep next weekend on the radar scope for the potential of some wintry weather. The model data is obviously confused with how things play out. This almost ALWAYS happens when something is 5-7 days away…especially systems that come from the SW part of the country.

There is a lot of complications with next weekend. Nothing would surprise me…from a sunny and cold weekend…to some sort of ice/sleet and or snow or even a changing to a cold rain event. That’s why it’s not worth getting all revved up about at this point. Just something to be aware of. For weather enthusiasts though…one has to look at the model data and try to dig a bit deeper. Unfortunately that can bring more questions than answers which I think is the case here from this point out.

Many forecasters, especially TV people, will hug and take to the bank the GFS (Global Forecasting System) model.  Perhaps it’s because it comes out 4 times a day. Maybe that’s the way they were taught…or perhaps it’s plain laziness. That’s fine if it pays off for them (and sometimes it does)…everybody has their own preferences I guess. When I see TV people take the exact GFS output and treat it as gospel though…it’s a curiosity to me at least. It’s funny, sometimes I don’t even have to watch a TV station to know their forecast…all I have to do is look at the GFS model.and I know what they’re going with on the air. Many TV people don’t even bother to look at the other output from the GFS model suite…and I’m mainly talking about the ensembles.

Let’s use an example from today’s GFS model run…for next Saturday morning.

Here is the operational GFS model that everybody looks at, including me.

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GFS Operational model for SAT at 6AM

One may look at that and say…well there’s really not much to look at here…any real precip is north and south of the region. It’s a very cold look for sure. 1051 mb highs in the upper Midwest are cold things during this time of the year.

One could then say…well nothing is going to happen here.

I choose to look deeper…let’s see what the other various GFS ensemble members say. Is there confirmation of the model above…or should there be at least some questioning of the output.

gefs_ptype_ens_central_25

The various other GFS model members that are averaged together to come up with an ensemble mean. This is for the same time. What I look for is confirmation of the earlier map I showed or reason for doubt.

Here’s what I see…about 11 members of the same model…showing something more significant…and in some cases MUCH more significant…that’s about 50%..and that leads me to question the “operational” model more for accuracy.

It’s worth backtracking a bit and talking about what an ensemble is. Basically it’s a model run with different initiation scenarios and sometimes even different physics in the member itself. There are some 21 different “members” and the averaging of all those members allows one to come out with a “mean” forecast. The main idea being you’re taking many different solutions (range of possibilities) and hoping for a more accurate end average.

Here is the definition from the National Center for Enviromental Prediction (NCEP)

“The National Centers for Environmental Prediction (NCEP) started the GEFS to address the nature of uncertainty in weather observations, which is used to initialize weather forecast models. The proverbial butterfly flapping her wings can have a cascading effect leading to wind gusts thousands of miles away. This extreme example illustrates that tiny, unnoticeable differences between reality and what is actually measured can, over time, lead to noticeable differences between what a weather model forecast predicts and reality itself. The GEFS attempts to quantify the amount of uncertainty in a forecast by generating an ensemble of multiple forecasts, each minutely different, or perturbed, from the original observations.” end text

The more widely different the individual solutions the more “doubt” that should enter your mind about the model itself. When the ensemble members are more aligned with the “operational” model then confidence can increase. That rarely happens on storms from this far out though.

I typically use the GFS model as my 2nd model choice. I’ll typically look a the EURO model and it’s ensembles 1st…then the GFS and it’s ensembles…then the Canadian model. Heck a few weeks ago I was looking at a model from Japan if you remember in search of snow for KC. Again this is my forecasting way. Many TV meteorologists just use my choice number 2 and their work is done.

All of this though should NOT BE used as gospel and goodness knows the EURO model…which statistically is superior to other model suites…goes wayyy off the rails sometimes. Interestingly when the weather gets more complicated in the Northern Hemisphere both models see verification scores go own…except the EURO doesn’t perform as poorly as the GFS during these times.

ecmwf_gfs_nh_f120_recent

Here are the verification scores between the EURO and the GFS. The EURO is in BLUE

Again that’s for the whole hemisphere so it’s a bit difficult to say which performs better in the Plains of the USA…but for a longer term forecast…about events days away…you get the idea.

With ALL that said, and this blog is venturing into missive territory now, I think even the EURO went off the rails a bit today in terms of how it’s handling the next weekend system. Today’s run…takes the main upper level storm that it drops towards Tuscon, AZ on Saturday (southern AZ snow in the mountains?) and shears it out towards Dodge City on Saturday. Seems a bit unusual to me. I think I see why it’s doing that but sometimes, regardless of what model(s) you look into for guidance(!), a model just doesn’t look right. To me the EURO today just doesn’t “look” right.

Even it though has something concerning for next weekend (especially Saturday) with the cold arctic air hanging on and a strong and moist flow aloft over that air mass (ice or sleet).

So what do we do. Well we don’t really. I just say what I’ve said for the last few days…be aware of next weekend. Something wintry could happen. Let’s not sweat the details at this point. Obviously there is a BIGGGGGGGG event next Sunday and that is in the back of my mind.

OK this turned into almost 1750 words…but I hope it gives you an idea of how I approach things in the big picture at least and how I try and dig deeper to find doubt and confirmation about what can and or won’t happen when making a forecast. I hope it makes sense.

Our picture of the day is from Jandy Moore of Breckenridge, MO

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Up in Caldwell County

Joe

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