Saturday, December 31, 2016

MikJournal January 2017 Prediction

Well, it's hard to believe, but after December went into the deep freeze, almost assuring our region would be looking at below normal temperatures, both Louisville and Lexington's temperatures came roaring back and may finish at or even above normal for the month.

Weather patterns moved much faster than even I anticipated. While we did see some freezing precipitation, it was very light, and the snowfall, despite several opportunities, did not amount to much at all.

Strong low pressure systems helped offset brutal cold with record-setting warmth at times, sometimes nearing 30 degrees above average, and above normal rainfall, which was desperately needed.

Therefore, I would say that my December's prediction was not that great. I'd give it a 'C'.

Makes me wonder, should I go on with January's prediction? Hmmm.

Okay. Here it goes.

January will start out quite active with yet another in a series of strong low pressure systems traversing the real estate.

Nevertheless, just like last month, brutal cold will be settling in, possibly setting up additional opportunities for wintry precipitation.

Actually, the teleconnection pattern called the AO, or the Arctic Oscillation remained positive for much of December. Now, looking back, the AO+ did indeed provide a 'milder' regime for our region despite the occasional cold snaps.

What will the AO's effect have on our weather this month? It will favor more opportunities for snowfall.

The Arctic Oscillation will be dipping into negative. This sets the stage for some dramatic winter scenarios that may unfold right here in our region.

As I have mentioned before in some of my comments, look for an AO- signal that will be trending upward for our best snowfalls. Otherwise, a negative AO is still a good predictor since that means the cold will be around to support something related to winter.

A prolonged cold spell will help keep temperatures suppressed. Therefore, below normal temperatures should be expected through the middle of the month. I am expecting the AO to be solidly negative by then. But, I do expect the AO to begin an upward trend maybe before the 15th.

What I'm saying is that if there is a storm system nearby at about that time of the month, an AO- trending upward and a decent storm system could mean a blockbuster snow for the region.

Some places may see double-digit total snowfall for the month (not just in one storm, which may happen...).

I know there is a storm system that is poised to affect the region later in the first week, but it's the middle of the month that I am more excited about.

During the third week of January, I am expecting the 'January Thaw' to commence in earnest. Warmer temperatures though may not be enough to offset the cold this time.

Therefore I'm expecting below normal temperatures for the month with possible above normal snowfall for the month.


Monday, December 26, 2016

MikJournal Monday 12/26/2016

Good morning. Wow. Last night's dense fog and 50 degrees led to me waking up this morning to a balmy 64 degrees with a few stars shining above. I had to check the calendar on my phone just to make sure I didn't hibernate through the winter. It really feels like Spring out there.

But, of course that won't last too long. More on that in a moment.

First, I updated the Mesonet site's wettest of the wet for this year. You can find this on the side of the blog. What a contrast in amounts of precipitation this year.

Western Kentucky leads the way with a ridiculous 80+" near Murray. However, here is a 'hmm factor'. Using the Great Circle formula calculating the coordinates between Murray and nearby Hickman to the west, I came up with about 50 miles as the crow flies that separates them. But, the quantitative precipitation disparity between the two locations is rather enormous. Hickman's precipitation readings is one of the driest locations in the state, coming in at 41.68". In other words, Murray has received nearly twice the amount of rainfall than Hickman in just that short amount of distance. If there are no quality control issues at these Mesonet sites, which I am not aware of any, a difference of some 40" over 50 miles is simply amazing, nearly unprecedented for our region.

Well, there has to be a driest of the dry, right? In Nicholas county, 37.91" has been tallied through yesterday. In fact, several areas around and including Lexington's Mesonet site are reporting under 40" for the year.

But, for many of us, drought concerns are easing substantially. So, now let's get on to winter already.

I looked at the snowfall analysis for December 25, 2016 and compared that with last year. You remember last December, don't you? One of the warmest Decembers on record.

Well, here is a breakdown of how much ground was/is covered by snow....

National (12/25/15):  37.2%
               (12/25/16):  44.1%

Midwest (12/25/15):   9.7%
               (12/25/16):  16.7%

Nothing too impressive, although regionally, the percentage for 2016 does compare favorably with 2014.

Speaking of snow, when are we ever going to see some snow covering our grounds? Well, we do have to be patient. It seems with all of that cold air we have had recently, we expected more opportunities for some type of accumulating snowfall. Storm systems were just a bit too strong, being able to draw up Gulf warmth thereby providing more rainfall instead.

While I am not dancing-on-the-ceiling optimistic about snowfall chances over the next 10 days, I am a bit optimistic that some may see some whiteness on the ground before January 7. Afterward, things may get rather interesting region wide. Clashes of cold air and a possible strengthening of the SE ridge may make things interesting around here. But, I'm still digesting data and looking at other signals, as computer forecast models still aren't up to the challenge of giving me anything to work with.

I will be putting out my January prediction later this week.

Have a good day and a good week.


Friday, December 23, 2016

Teleconnections Coming Back

Ahh, the other alphabet soup aside from the numerical forecast models. I'm talking NAO, AO, PNA, and EPO, common teleconnection patterns helpful in forecasting behavior of winter patterns.

Despite the impressive cold shots recently, all of the teleconnections I recommend have shown no lasting chill and wintry conditions hanging around.

The Arctic Oscillation (AO), a major player in the winter time, has really been a non factor thus far. Let me explain.

The AO has been in its positive state for a while now, since the beginning of the month. So, one would expect a milder pattern overall for our region. "Not so fast my friend" in the words of Coach Corso.

An unusual or anomalous October snowpack in Siberia and Eurasia as a whole combined with a rather weak polar vortex had contributed to the very cold air here in our region. The disruption to our weather patterns because of the above combination looks like it has finally run its course.

Therefore, we can get a truer, more accurate look at how the AO will now behave over the next few weeks. Used in tandem with the other teleconnections above, cold and snow chances should be more definable, and forecast models might do a little bit better in predicting future outcomes.

Right now...forecasts show:
AO Positive, trending downward to neutral or slightly positive over the next two weeks.

NAO Positive, trending downward to neutral or slightly negative

EPO Positive, trending downward to negative

PNA neutral/negative to remain more negative

Right now, as of today, none of the teleconnections favor a snowy outcome. However, forecasts at least show the NAO and EPO wanting to support a wintry pattern over the next 10 days or so.

But, the AO is still expected to remain positive, and the PNA negative favors a trough west, ridge east scenario. At the very least, a warmer southwest wind will mitigate snow chances unless very cold air is in place. Which we have seen leads to higher ice chances than snow chances.

Remember to keep your eye on the AO index. Some of the best snowfall I have seen here during the last few years have occurred when the AO was negative trending upward.
Right now, we don't have a negative AO yet. A negative EPO helps as well. Team those together and we could be looking at a higher chance for snowfall. Of course, other variables come into play that might blow your mind. If you want to, research the QBO and the MJO to see how their effects may influence our pattern as well.


Saturday, December 17, 2016

MikJournal Thoughts About the Changeable Weather

We have a balmy kind of day out there, at least compared to what we have been enduring. Light amounts of precipitation occurred overnight into the first part of the day here in Louisville. At the airport last night, I did not see any sleet pellets, just plain light rain and drizzle. I'm sure others saw some sleet, but as expected, no issues with that.

Now, let's turn our attention to the rest of the day and tonight. Did you know a severe weather threat exists for part of the region? And the same areas may see some frozen precipitation several hours later. Shew! Crazy, I tell ya.

A Winter Weather Advisory is in place for much of western and central Kentucky overnight. Mainly for impact as moisture on area roadways will be hard pressed to dry out, since we will be having light freezing rain, freezing drizzle, and occasional sleet mixed with snow going on. No way around it there is going to be slick spots on area roadways. However, salt crews may be able to alleviate much despite the very light frozen precipitation falling. But, watch out for your untreated porches and sidewalks.

More updates later if necessary. Stay safe everyone.


Monday, December 12, 2016

MikJournal Monday 12/12/2016

Good morning and welcome to another installment of my MikJournal Monday. Crazy weather times are coming. You've been warned.

First, another episode of soaking rainfall, making a dent in that severe drought region wide, is just another in a series of what the Climate Prediction Center is calling for moderate to high chances of above normal precipitation over the next two weeks for the region.

Well, if that's the case, Christmas may be more wet than white. However, there is still time to sneak a cold airmass in with all of this available moisture in place. Again, though, the odds are already beginning to dwindle.

The first half of this month has delivered below average temperatures with a couple more shots of frigid air to go. Rainfall has been about average for the month so far here in Louisville and Lexington, but still a little bit below average in Bowling Green.

The coldest air of the season will be arriving by the middle of the week and staying for a couple of days. I don't remember giving an invitation to Old Man Winter. He just shows up whenever he wants, I guess. But, low temperatures may tumble into the single digits for some of us, only to surge once again ahead of another strong storm system, poised to bring yet another shot of very cold air behind that.

It appears the best chances for accumulating snowfall will be later this week. However, it may not be a pretty picture. I like my snow pure, not tainted with a mix of whatever. And that may be the case later this week.

Although the dreaded 'ice' word could be a part of the vernacular this week, I don't expect any widespread and serious issues. Things are going to move very fast this week. Precipitation transition will likely be quick as well.

Afterward, the teleconnections I follow, show a unanimous agreement AGAINST winter weather for the second half of the month. I guess it still can snow during this time period, but it won't stick around. The forecast teleconnections over the next 10-14 days are for a +AO, +NAO, -PNA, and +EPO. I would prefer to see the opposite sign for every one of those teleconnections to support a lasting wintry scenario.

In addition, the CPC is calling for modest chances for above normal temperatures, especially during Christmas week. Therefore, if you don't like the icebox, just wait a little longer.

One way to look at it, if you're planning to travel during Christmas week, a milder weather pattern around here may help ease travel concerns.

All of this is still a couple of weeks away. As always, things change. Just something to talk about for now. Enjoy the 'ride' this week.

Oh, depending on how the upcoming weekend storm system develops, I may chime in with thoughts about snow or ice, if it looks like a problem for the region. Otherwise, till next time.


Monday, December 5, 2016

MikJournal Monday 12/05/2016

Good Monday to all. I just wanted to briefly stop by and invite you to check out my 2016/2017 Winter Prediction released late last week. You may wonder why I call it a 'Prediction' instead of a 'forecast' like others. Well, a forecast tends to have a compilation of reliable data that should produce a relatively accurate picture of what's going to happen over a said period of time. However, a prediction relies on many assumptions and the data may not be enough to produce an accurate assessment of what could happen over time. I look at particular points of data and use them as a weight for what I believe will control our weather here locally. So, it is possible I could have overlooked an important driver for this upcoming winter that would in effect disrupt my thoughts of what will happen this winter. Therefore, my assumption or prediction may not be that accurate. I call it a disclaimer.

At the same time, meteorologists put out these 'forecasts', claiming they have all of the tools necessary to make an accurate assessment of what will happen. In reality, all of their hard work cannot reliably go beyond a few weeks. Even with an improvement in technology, the data is still not where we need to be in order to make a 'forecast' for an entire season spanning at least 12 weeks. In reality, these meteorologists do just what I do and focus on a few sets of data they feel will contribute more toward how the winter season will behave. They choose to call theirs a forecast, mine I choose to call a prediction.

Don't be fooled by the mentality that the winter season forecast is 'just for fun, entertainment purposes only.' Some of these professionals really take this stuff seriously and spend inordinate amounts of time trying to figure out what will really happen. And rightly so. Many government services and other industrial giants rely on seasonal forecasts to be better prepared and equipped for providing its citizens or residents what will be needed when it is needed.

And that's good and all. But, this forecasting x amount of inches of snow will fall during the next 12 weeks or so is really not a forecast at all, if you think about it. There is barely enough data that can help us put together a reliable forecast out more than 2 weeks. Just a simple 'above average, below average' and useful data of what is average for my region is really all that is needed for me. Then, we can use our own imagination to figure out what above average or below average will mean for our locations.

Have a good day and rest of the week.


Friday, December 2, 2016

MikJournal 2016/2017 Winter Prediction

A summary of the upcoming winter 2016-2017...
For the official winter months of December through February, I am expecting below normal temperatures for the Louisville and Lexington areas while we should be on either side of normal snowfall, or favoring slightly above average for Louisville and slightly below normal for Lexington.

I will introduce the December contribution for the winter during this segment....

The climatic pattern favors below normal temperatures across the region. I think that this will largely be due in part to a favorable snow cover over the Eurasian areas and low sea ice extent, which helps increase high pressure over the Arctic region leading to lower pressure for the mid latitudes. My Meteorologist instructor always says that it is easier for pressure to flow from high to low. In other words, strong polar winds, which generally keep the cold up there, will be more relaxed, allowing for chunks of cold, polar air to dive southward toward the relatively lower pressure in our neck of the woods.

What I just described is the Arctic Oscillation, a type of teleconnection that helps predict the behavior of cold air based on the differences in pressure of the polar latitudes and the mid latitudes. I will be using this feature as a primary component in my month to month predictions for temperatures.

Another important driver that I personally think may contribute to the winter is the unusual southeast drought. While we have seen an overall easing of the devastating, prolonged dry spell there, I think this pattern has already upset the balance for the first part of our winter. Archived data shows mixed results for overall snowfall amounts during December mired in a severe drought for our region.

I do think we will see more opportunities for snowfall this month than in years past, since the cold air will be more prominent. However, after this month, we will have to wait and see if the Southeast ridge establishes a firm footing and where, which may introduce several chances of the cold versus warmer air. Increased chances of freezing rain/drizzle may already become a problem for parts of the Southeast later this month into the first part of next year.

January's prediction will be out later this month...


MikJournal Monday 02/25/2019...Drying Out

What a wet pattern we have been enduring. Will we finally dry out? Welcome to another installment of MikJournal Monday, the 25th of February...