Ice and De-ice

Good morning, Somerset KY. A little souvenir left over from yesterday's overachieving ice event. You received 0.2 - 0.25" ice accumulations, a common amount for several areas of south-central KY. Things look to improve dramatically today. Still, beware of leftover moisture on the ground that is likely frozen this morning.

Even here in Louisville, black ice looks to be an issue on some untreated subdivision roads, like my street.  Thanks to barely any snowfall, temperatures should rebound above the freezing mark for many locations across Kentucky, except the usual cold spots of far northern Kentucky and elevated parts of eastern Kentucky.

A nice warmup is in store starting tomorrow and should last into parts of Wednesday before we get slapped with another backhand of Ole Man Winter's dry, cracked, and calloused knuckles.

Here's your next teaser. From the CPC, an updated page from yesterday shows the 6-14 day outlook that features below normal temperatures for all of Kentucky and above normal precipitation for parts of the state, roughly from I-71 and I-75 corridor east including all of eastern KY. Well, you figure it out. Probably means nothing, though.

MS

First Call for Snowfall 01/24/13

Well, I've had a chance to examine the recent runs of the NAM and do lean heavily toward this model as I forecast these amounts. I will throw in what my MrHP forecast will be along with my personal expectations.

First, let me say there will be quite a bit more of mixed precipitation than snow for this event. To summarize, I expect all snow from Carrollton northeast to Cincinnati and east to Ashland. Louisville should expect a mix of snow and sleet. Lexington also a mix of snow and sleet, although more snow than Louisville. Bowling Green could see freezing rain and sleet throughout the event while Somerset could see freezing rain and sleet before changing to all snow later in the event. Again, a very complex setup.

MrHP says...
Cincinnati 1-2"
Louisville <1" + sleet
Lexington 1" + sleet
Ashland  1-3"
Somerset  0.1 - 0.2" ice, <1" snow + sleet
Bowling Green 0.1 - 0.2" ice + sleet

MikeS says...
Cincinnati  1-2"
Louisville <1" + sleet
Lexington  1-2" + sleet
Ashland  2-3"
Somerset  1" + sleet, 0.1 - 0.2" ice
Bowling Green 0.1 - 0.2" ice + sleet

NWS says (as of 12:30pm est)
Cincinnati  1-3"
Louisville 1" + sleet
Lexington 2"
Ashland  1-3"
Somerset  <1"
Bowling Green 0.2" ice

Very subtle differences in the forecasts above. I will say that the NWS has the best track record . However, I'm beating my MrHP forecast model for the season. The most obvious differences are that Lexington is expecting no sleet and Somerset no ice according to NWS offices.

MS

Forecasting Snow For the Region - Try This One

Sure, we can look at the forecast models, you know, GFS, NAM, Euro, GEM. Often, we leave it to the pros to interpret what those models will spit out in terms of precipitation for the area. And yes, all eyes are glued to the same models again as they fluctuate in their various runs for the next upcoming system.

Folks, this is basketball country around here. We live and breathe this stuff, the tickling of the nylon, the diaper dandies, and the thunderous throwdowns. The atmosphere around here gets so heated, I think we can alter the weather at times. You know, it could be true.

Looking at our most recent heaviest snowfall in January, it was January 20, 2011 that Louisville recorded 3.6" and Lexington 3.3". I can't remember how the meteorological computer models fared with their forecasts but I found an interesting correlation that may prove useful for our next storm system in a couple of days.

Introducing the NCAA model.

Something else noteworthy occurred in January 2011. The University of Louisville and Kentucky Men's NCAA basketball teams suffered a loss in the same week.

In fact, UL lost to Villanova 88-74 at Villanova on 1/12. UK fared no better at Tuscaloosa on 1/18 when Alabama beat the Cats 68-66.

Two days later, on January 20, 2011, Louisville and Lexington recorded their respective snowfall amounts previously mentioned.

Last night, UL lost to Villanova at Villanova and UK lost to Alabama at Tuscaloosa. Could this be deja vu? Well, if history repeats itself, then two days or so later, Louisville and Lexington should be looking at possibly 3" of snow on the ground.

Hey, this model makes just as much sense as the ones we hear about on a daily basis from our weather heroes. Take care and I'll give the NAM a few more chances to catch up with the NCAA model.

MS

Snow Chances 01/23/13

Ah, I said beware of the 'snow job' fallacy during a prior post. Data for our upcoming storm system comes in weaker mainly because the phasing aspect may not materialize as assumed. Nevertheless, my low end conservative guidance remains in play (2-3"). And things can still change. I'll be taking a look at the NAM model throughout the day. It is perhaps the main driver in my MrHP (Mid-range Highest Probability) snow forecast. The other factors include the timing (24-36 hours out), upper air forecasts, surface temperature forecasts, and to a limited extent (and I do mean limited) my personal expectations based on observed data.

Even if this forecast does not favor snow enthusiasts' expectations, winter is not over yet. So far, the CPC has put out these mid-range forecasts that have been surprisingly accurate, at least for our region. They predicted the above average warmth and wetness just before the middle of the month. They predicted the below normal cold and below normal precipitation for this period, again some 6-14 days out.

Mark this on your calendars. The January 28 - February 03 time frame is expecting above normal precipitation. Interestingly, the first part of February could be looking at below normal temperatures. Coincide the cold with the precipitation and we could be looking at the elusive 'big one' for our region. Or at the very least, our biggest snowfall of the winter season is in store.

You can check out their predictions at the link below...

CPC Outlook and Information Page

MS

Another 'Snow Job'?

Snow Job - "an attempt to deceive or persuade by using flattery or exaggeration" (Dictionary.com)

For at least a couple of days now, NWS offices and other mets have been advertising an 'impactful' winter storm for the Jan 24-26 time frame.

The NWS Louisville office reminds us that despite high confidence for a storm system to affect the region, precipitation types are still 'up in the air'. At this time, a southern track remains the preferred choice.

If the southern track should verify, then sizable snow amounts can be expected, generally north of a line from Beaver Dam to Richmond. However, as usual, Kentucky seems to be the battleground for transitional precipitation.

Any shift in the storm track will impact snow and ice amounts significantly. However, there seems to be growing confidence that a wintry scenario will unfold across the state due to the presence of a retreating yet still present Arctic air mass by Thursday.

Since this type of cold air is difficult to budge at the surface, how thin will the Arctic layer become? If precipitation falls later than expected, warmer air will nudge in from the south in the upper layers of the atmosphere, possibly falling as rain for some of us. The problem then becomes, if temperatures are below freezing, perhaps 3-5 degrees below freezing, any liquid rain that falls will freeze on contact with surfaces and other objects (thus freezing rain).

I'm not here to exaggerate precipitation amounts and types. The storm system is still just offshore. Remember, as I know from personal experience, Arctic air masses are typically stubborn. Cold air likes to hang around, especially near snow-packed areas. There's not much snow out there. Also, these air masses have a great deal of dry air with them. Any precipitation that falls generally have a difficult time making it to the surface.

Depending on the speed, strength, and track of the storm system, it will be interesting to forecast how a developing winter storm will fare against a retreating yet somewhat strong Arctic air mass.

Nevertheless, 2-6" looks like a conservative guesstimate for those who get mostly snow. Although this sounds like an appreciable amount, any mixing of precipitation will reduce those totals in a hurry.

The main concern that I have with this upcoming system is the ice potential. It could become a widespread issue, not like the last storm where only a relatively few locations were significantly impacted.

If the current track remains, ice accumulations for Campbellsville to Corbin  appear possible, at least somewhere in that region, maybe even more locations of eastern KY as well.

For now, let's just wait and see as the storm system comes ashore. Upper air data can then be calculated and storm track along with p-types will become a little clearer.

Looks like another tough snow job to forecast, or should I say, beware of those snow job forecasts that persuade you this will be an easy storm to forecast.

MS

January Mid-Month Report

A good time to look at what has and what will happen.

Overall, it's been wet and mild...thru 1/16
Louisville  234% of normal precip
Louisville 4.8 degrees above normal

Lexington 181% of normal precip
Lexington 5.3 degrees above normal

Bowling Green 203% of normal precip
Bowling Green 5.8 degrees above  normal

Jackson 179% of normal precip
Jackson 5.5 degrees above normal

The CPC says for the time frame of Jan 22-26, temps retreating from below normal readings. In fact, Jan 24-30 time frame shows above normal readings across much of the south, including KY.
I'll be interested in seeing how this unfolds as some are pointing toward a very cold period during this latter period.

Here is what the CPC says for the month of February...

February Temps
February Precip

MS

Mix It January 15, 2013

Wintry mix for many locations today. Therefore, WWAdvisories posted, generally south of Louisville.

Things to think about...

NAM radar shows mostly rain, with freezing rain/sleet along the Ohio river.
This seems to contradict with forecast surface temps, especially south of Louisville.
For Louisville, NAM suggests liquid equivalent of 0.18". Sounds excessive.
According to upper air forecasts, the freezing point will be right over Louisville (how many times have we seen that?); therefore, any precipitation that falls will be a mix of rain and sleet. Surface temps look to be near the freezing mark.
I think main roads should be okay here in Louisville. The usual bridges and overpasses along with secondary roadways could receive a slight glazing at best. However, this does not appear to be a significant event.
Temperatures will need to be monitored, though.
Don't know if WWAdvisory will be posted for Louisville. It will be a close call. Still, exercise caution, regardless.

The way I see it, you already know the forecast. Areas NOT under the WWAdvisory can still expect a mix of sleet and possible freezing rain. Therefore, treat the situation as if we were under the Advisory. If you know that you're running low on gas, you don't need to wait for the gas light to come on to get gas. Similarly, you know there will be a wintry mix for some, which requires caution when driving. You don't need to wait for the NWS to issue an Advisory to decide if you're going to drive with caution.

HPC Freezing Rain Probability Jan 15-16

MS