Thursday, December 16, 2010

12/16 - 2:30pm - Ice Photos

It seems we received some of the worst ice accumulations in Kentuckiana here at my house in Southeast Louisville. Check out this slideshow for some pictures of the impressive ice accumulations that I took earlier this afternoon:

It took 30 minutes to get a minivan out of our driveway using sand. Trying to walk on any of this ice isn't a good idea. Glad that I only fell once! It should be noted that all the major roads in Louisville are pretty good right now, but those streets that have not been treated are extremely dangerous. Use caution if you have to be out today.

I'll be heading out to on vacation to Florida tomorrow so there won't be any blog posts for about a week. I should be back just before Christmas, so I'll be sure to post if any wintry weather heads toward Louisville after that point. It appears that things will quiet down for a short while, so it's certainly a good time to take a break!

12/16 - 11:30am - Ice Accumulation Numbers

The temperature in Louisville got up to 32 at around 8am this morning, but we're now back down to 29 degrees. That's not good news at all because the accumulated ice simply won't melt with temperatures below freezing and cloud cover. Overall, Louisville did get around 0.5" of ice in places as expected, but the expected 1-2" of snow simply did not happen due to warm air advection aloft that traveled north quicker than expected. Here are some of the ice accumulation totals from the NWS in Louisville:



*************************ICE ACCUMULATIONS**********************

ACCUM  LOCATION             ST   COUNTY               TIME
-----  --------             --   ------               ----

0.5"   VALLEY STATION       KY  JEFFERSON           500 AM EST
0.5"   ENGLISH              IN  CRAWFORD            900 AM EST
0.3"   BROWNSVILLE          KY  EDMONSON            200 AM EST
0.3"   CASEY                KY  BUTLER              200 AM EST
0.3"   TELL CITY            IN  PERRY               900 AM EST
0.3"   ANCHORAGE            KY  JEFFERSON           900 AM EST
0.3"   DOE VALLEY           KY  MEADE               900 AM EST
0.25"  HOLLAND              IN  DUBOIS              600 AM EST
0.25"  FRANKFORT            KY  FRANKLIN            645 AM EST
0.25"  GEORGETOWN           KY  SCOTT               730 AM EST
0.25"  ELIZABETHTOWN        KY  HARDIN              745 AM EST
0.25"  CORYDON              IN  HARRISON            705 AM EST
0.25"  SALEM                IN  WASHINGTON          600 AM EST
0.2"   NWS LOUISVILLE       KY  JEFFERSON           900 AM EST
0.2"   FERDINAND            IN  DUBOIS              530 AM EST
0.2"   PORTERSVILLE         IN  DUBOIS              530 AM EST
0.1    LEITCHFIELD          KY  GRAYSON             715 AM EST
0.1"   BOWLING GREEN        KY  WARREN                MIDNIGHT

I'll post some more photos of the ice later on today. Some of those icicles out there are pretty big! I think Louisville will stay dry for the rest of the day but areas near Lexington will receive just a little more freezing rain.

Wednesday, December 15, 2010

12/15 - 11:40pm - More Ice in Louisville?

Jefferson County Public Schools are closed today (Thursday) due to the ice accumulations overnight. Great decision given the dangerously slick roads and driveways in Louisville. I know I have a few readers who go to my Alma mater duPont Manual High School, so you guys have the day off. Enjoy and be safe!

***2:30am UPDATE***
The temperature is now up to 28 °F in Louisville as warmer air drives northward. Still think we'll be below freezing for the next few hours. I just snapped a picture of some icicles forming on our deck railing at my house... check it out. Took another walk around my driveway as well and found that ice skates were preferable to tennis shoes. Don't go out if you don't absolutely have to for the next few hours.

***1:45am UPDATE***
My driveway (and most sidewalks/untreated streets in Louisville) is a sheet of ice and we're still awaiting another big batch of freezing rain in Louisville. That precipitation should be here within minutes and we'll continue to see freezing rain fall until around 7am or just before. Temperature at my house is 26.7 °F and the airport is still holding at 27 °F. You have to go down to Bowling Green, KY to find temperatures just above freezing, so I don't think any relief in the form of warmer air will make it here in time to spare the morning commute in Louisville. Still some snow falling to our north and east, but it's transitioning to sleet/freezing rain as warmer temperatures aloft work their way northward. I still think we're on track to get somewhere near 0.5" of accumulated ice here in the Metro, especially since radar returns are filling in to our west.

We started out with some snow in the Louisville area around 10pm this evening, but most of Jefferson County has now switched over to freezing rain and sleet. With what I'm seeing on radar and surface observations, the heavy snow will still fall in areas just northeast of Louisville as you go toward Cincinnati. The heavy ice accumulations are going to happen right here in Louisville I think, up to a half inch or more in places. Areas near Springhurst and Prospect in Northeast Jefferson County may pick up some of that heavier snow, but most of Louisville will stick with freezing rain and sleet overnight unless temperatures above the surface cool a bit. I'll continue to monitor the trends, but as of right now I think Louisville and points south aren't going to see any more snow tonight except for a few snowflakes.

No word on school cancellations in Louisville yet (JCPS says they'll make a decision at 4am), but I'm already seeing reports of slick roads in the suburbs. It's 25 degrees here at my house and 27 at the airport, so the liquid rain that's falling from the sky is freezing on the surface. Needless to say, things are going to be very slick on those untreated roads in the Metro tomorrow if temperatures continue to stay below 32 at the surface with freezing rain tonight.

12/15 - 9pm - Snow/Sleet Initiating, Winter Storm on Track

***10:15pm Update***
Snow and sleet are falling simultaneously at my house in SE Louisville near Fisherville with reports of snow/sleet/freezing rain coming in all over Kentuckiana.

Helpful Tip: It's sometimes hard to tell what type of frozen precipitation is falling because it's dark outside. If you're having a hard time trying to determine what's falling, stick a flat object like a tupperware lid, book, magazine, or pan out your door for a few seconds and then bring it inside or under a light source quickly. If it's all wet, you're experiencing freezing rain, any ice pellets on there are sleet, and of course you'll be able to pick out the snowflakes visually. Be sure to do this very quickly so that you're able to inspect the accumulated precipitation on your flat surface before it melts!

Precipitation is breaking out across Kentuckiana and reports of snow and sleet falling are coming in from those areas you see with precipitation on radar below:

The bands of precipitation to the southwest of Louisville are filling in quite quickly and we'll see those come into the Metro area within the next hour or two. We're still on track for 1-2" of snow before 1am tonight, but a few of the short-range models are indicating a 2-4" accumulation in Louisville if these snow/sleet bands fill in and set up well. We'll see if that happens, but for right now all eyes are on the radar. The snow and sleet will eventually turn in to freezing rain sometime between 1am and 2am here in Louisville, but areas to our northeast across the Ohio River in Indiana will most likely stay all snow and sleet and see accumulations over six inches in some cases. Areas to the south and west of Louisville like Elizabethtown, Bowling Green, etc will have little snow and see mostly sleet and freezing rain tonight. The good news for them is that surface temperatures have a good shot at getting above freezing later on tomorrow, whereas here in Louisville and points north that probably won't be the case.

I'm getting lots of questions about schools being open tomorrow and right now I can't supply a definite answer. Locally in Louisville I think the side roads and streets will be dangerous tomorrow morning (4-10am), so that will probably be a strike against schools being open tomorrow. Road crews are hard at work on interstates and major roads, but we'll see how surface temperatures cooperate with that overnight. Areas to our north with the heavy snow will also see many cancellations. This is still very much a "wait and see" game right now, but it's not looking too good for us weather-wise at the moment.

12/15 - 5:30pm - Louisville Winter Storm CRUNCH TIME!

The onset of Louisville's first major mixed precipitation winter storm of the season is just hours away and the forecast is still very difficult. The National Weather Service has extended tonight's and tomorrow's Winter Storm Warning to counties in Southern Indiana that were previously only in an advisory. The reason for this is the increase in precipitation totals that both the NAM and GFS have been hinting at today. Those areas in Indiana will see all snow and sleet, with accumulations up to six inches in places.

Here in Louisville the snow should start from the southwest near the 10pm hour and possibly mix with sleet before 1am, with accumulations of around 1-2". Based on the model guidance I've seen, I think we'll switch over to a period of sleet with some freezing rain mixed in after 1am. Freezing rain will become dominant in Louisville just a couple hours after that and last until around 7am with ice accumulations ranging from 0.25" to 0.5". The 18z GFS model (pictured top left) and the NAM both keep Louisville just below freezing at the surface during the entirety of the winter storm, but we're going to have to watch that. The snow we have on the ground will influence the surface temperatures across the area, so the computer models may be running too warm at this point. As I've said before, Downtown Louisville could get a degree or two above freezing during the afternoon and that will help road conditions improve tremendously. The 18z NAM BUFKIT output (second image on left) gives Louisville 1.7" of snow/sleet with a half inch of ice accumulation.

Even with all of this data nothing is set in stone. The storm is forming to our west right now and we're already seeing light snow and sleet falling to our west and southwest. Watching the radar trends and surface observations overnight (called nowcasting) will be crucial to see who gets what kind of precipitation. Louisville is historically the battleground between precipitation types and we'll be in that situation for sure tonight. The HPC (Hydrometeorological Prediction Center) has Louisville and areas south in a Moderate Risk for 0.25" of ice accumulation. Louisville and points north have been put under a Moderate Risk for 4"+ of snow accumulation as well, so we may very well end up with quite a bit of both snow and ice here in the city.

Should this system shift south just a few miles, Louisville would end up with mostly snow and accumulations would pile up to nearly half a foot. I've posted the 12z NAM snow accumulation output on the left just so you can see how incredibly close the heavy snow will be to Louisville, at least according to that model run. A shift northward would severely limit snow accumulations and put us in a mostly ice situation. Either way, Kentuckiana is set to get walloped by winter weather tonight. This will not be as bad as the January 2009 ice storm due to lesser ice accumulations and the potential for slightly above freezing temperatures during the daytime hours in Downtown Louisville and areas south of town as well. We'll see how it all plays out!

12/15 - 1am - Late Night Winter Storm Update

The 0z suite of computer models (GFS/NAM) is in and the verdict is not good for our winter storm here in Louisville and surrounding areas. Both computer models have increased the amount of precipitation that will fall tomorrow night through Thursday, but it still appears the time line I laid out in the blog post below is valid. The GFS model is now putting out 0.35" of liquid equivalent precipitation and the NAM just output 0.75". This is up considerably on both models compared to this afternoon's runs. Check out the 18z NAM model's accumulated freezing rain estimate for this storm on the left... it's showing the potential for a half inch or more of accumulated ice around the region.

I still think Southern Indiana north of Scottsburg will see mostly snow, which could add up to four or five inches especially as you head eastward. Here in Louisville we're on track to see a brief burst of moderate snow on Wednesday night before we go to sleet and then to freezing rain by Thursday morning. Like I said earlier today, Louisville's morning commute on Thursday is going to be treacherous if all the data we're seeing right now comes to fruition. Surface temperatures should be below freezing in Louisville throughout Wednesday night and Thursday (Downtown Louisville could get just above freezing on Thursday afternoon), so ice will have no problem accumulating on cars, roadways, overpasses, and everything in between. The computer models aren't accounting for the snow we have on the ground already, which will cool our surface temperatures, so it's difficult to gauge just where exactly it will get above freezing just south of town. The good part in all of this is that we will be fairly close to the freezing mark, which will make the salt on the roads much more effective. If surface temperatures were to be in the teens or 20's during this event, we'd have much worse road conditions. The HPC (Hydrometeorological Prediction Center) has points just south of Louisville in a slight risk for 0.25" of freezing rain or more (see right image), but we'll see how that plays out. I think we have the potential for 0.25" or higher of ice accumulation here in Louisville on Thursday, but those numbers will be fine-tuned as we get closer to time.

I'll post tomorrow with the latest data. Again, this storm won't break any records, but it will have a significant impact on much of Kentuckiana. Remember that I-64 and south will be under a Winter Storm Warning from tomorrow afternoon through Thursday afternoon and points north of I-64 will be under a Winter Weather Advisory for the same time period. The difference between these two is the potential ice accumulations, which warrant a Winter Storm Warning in place of an advisory.

Tuesday, December 14, 2010

12/14 - 1pm - Winter Storm WATCH for Louisville

A Winter Storm WATCH has been issued by the National Weather Service for Louisville and surrounding areas until Thursday afternoon. An area of low pressure passing to our south will give us a quick-hitting winter storm, meaning we'll only see its effects in Kentuckiana from late Wednesday into midday Thursday. There's talk at the NWS of issuing an Ice Storm Warning for portions of Central and North Central Kentucky if the freezing rain accumulations appear that they'll get near a quarter of an inch.

Storm Timing

Wednesday morning/midday: All Clear

Wednesday afternoon/evening: Light snow/sleet begins in the west and spreads toward Louisville as snow. Under an inch of accumulation expected.

Early Thursday morning: Snow switches over to sleet and freezing rain, becoming mostly freezing rain as the morning wears on. The morning commute will be a royal mess in Louisville. Based on the forecast models and guidance I'm seeing right now, most schools should be closed or delayed on Thursday due to the treacherous driving conditions on Thursday morning. Areas north of Scottsburg, IN should have snow throughout the entire event and I would not rule out a couple inches of accumulation up that way.

Thursday afternoon: Near and south of the Ohio River should see freezing rain end from west to east in the early afternoon hours. There could be a few snowflakes as temperatures aloft cool down on the west side of the low. Again, Southern Indiana from Scottsburg northward should stay with snow and possibly a little sleet as this system pulls out of the area.

The devil is in the details with this storm. How much freezing rain will accumulate in North Central Kentucky? Right now I'm thinking Louisville will see just under a quarter inch of ice accumulation whereas areas near Elizabethtown, Fort Knox, and Bardstown could pick up about a quarter of an inch. The GFS model is being conservative with precipitation amounts (0.27" liquid) whereas the NAM is pumping more into the area (0.56" liquid). I'm willing to bet we'll see something in between those numbers here in Louisville, some of that liquid falling as snow/sleet while the rest falls as freezing rain. Check out the annotated BUFKIT sounding from the NAM model at 4am on Thursday above (click to make it larger). You'll notice that temperatures between 4000 and 8000ft will be above freezing, meaning the snow will melt to rain while it's falling through that layer of air. The lower 4000ft or so of the atmosphere will be below freezing and that already thawed liquid rain will likely freeze when it hits the surface. There will likely be a period of sleet in Louisville as we transition from snow to freezing rain on Thursday morning. Like I said yesterday, only a few miles will make a big difference. We still have a decent snow pack in Louisville, so I do expect temperatures to stay below freezing here at the surface throughout Thursday except for some areas downtown where they may reach 33 degrees. Even though we're only about 36 hours away from this event, there's still wiggle room for all of this. If temperatures aloft aren't as warm as forecast, we'll see mostly snow in Louisville and the freezing rain risk would shift southward. On the flip side, temperatures at the surface could also nudge a couple degrees higher than expected (unlikely due to snow cover in my opinion) and decrease the ice problems on Thursday morning.

We'll see how this one plays out. The NWS in Louisville will upgrade the Winter Storm WATCH to either a warning or Ice Storm Warning at some point later today and I'll post the details of that on Twitter and Facebook immediately. Should any significant changes occur in the forecast, I'll post those on the blog.

Monday, December 13, 2010

12/14 - 12am - Cold is Here and Another Louisville Storm Looms

My apologies for posting so late today. I didn't expect the recovery time from my wisdom teeth removal procedure this morning to last so long, but I think I'm about 95% back to normal now. Cold temperatures are the big story tonight as clouds continue to clear out of the area and cooler air filters in from the northwest. Low temperatures will hover around 8 degrees early tomorrow morning and we're already well into the teens at the eleven o'clock hour here in Louisville. Check out some of the surface observations on the image to the right. Indianapolis and Evansville, IN are coming in at 9 degrees at the moment with temperatures getting even closer to 0 as you make your way toward Peoria, IL. Wind chill values will get a few degrees below zero tonight, especially in the suburbs of Jefferson and surrounding counties.

Our attention turns to yet another storm that should affect the Louisville area as soon as Wednesday evening. If you thought this past storm was a bear to forecast, try figuring this one out! Since temperatures will be hovering near freezing at the surface across the area with upper-air temperatures varying, this is going to be a real mess. The 0z NAM model run keeps Louisville and points northward mostly in the snow, but the 18z GFS had quite a mixed bag of precipitation for us, including freezing rain, sleet, snow, and plain rain. The 0z GFS is just now coming in and it appears that there will be a longer period of snow here in Louisville according to that run, but freezing rain or sleet could take hold on Thursday as warmer temperatures make their way in aloft (still need time for the BUFKIT output to be generated to find out exact precipitation type). If I had to guess right now, I'd say that Louisville and Southern Indiana will start out as snow on Wednesday night before switching over to either sleet or freezing rain sometime early Thursday before gradually changing back to snow as the storm ends. Should temperatures at the surface get just above freezing on Thursday, that period of freezing rain could turn to plain rain at times.

It's a real sticky situation as you can gather from my comments above. Since just a few miles will make a difference during this Wednesday/Thursday event, snow, sleet, and freezing rain amounts will vary wildly across Kentuckiana. I'll have an update tomorrow with more specifics and hopefully the computer models will have a better handle on this storm by then.

Check out some video that I shot of today's snow accumulations in Louisville below:

Be sure to select either 720p or 1080p and play at fullscreen for a high-definition experience.

Sunday, December 12, 2010

12/12 - 9pm - Snow is Making Things Hazardous in Louisville

Hazardous Roads
I just got back from a drive out on the Watterson Expressway, I-64, and the Gene Snyder. All of those interstates had snow on them, but they weren't quite covered. Needless to say, everyone is taking it slow and easy out there tonight. Most side roads and even some major streets have snow cover on them right now around Louisville, so take extra precautions if you're out driving tonight into tomorrow. With temperatures getting below 20 tonight in the city, the salt that Metro road crews have put down will not be as effective and major roadways could be difficult to drive on.

Snow Tonight
Louisville has been getting hit by multiple snow bands throughout the evening and it appears that at least a couple more developing in Indiana right now could hit us later on tonight. Most areas around the city and surrounding counties have seen an inch or two of snow with locally heavier amounts. These snow bands tonight could give us another inch or two in places, so a total snow accumulation of 2-3" in the city looks about right. Many area school systems are already announcing closures tomorrow and I'm inclined to think that schools around Louisville may have delays or closures based on the poor road conditions already present. (EDIT 9:23pm: Jefferson County Public and Catholic Schools have announced they will be closed tomorrow)

Gusty Winds
The winds are really going to pick up tonight on the backside of this storm. Winds just to our west in Paducah, KY and Southern Illinois are topping 25mph and those speeds are certainly headed our way. Winds tonight into tomorrow could get up to 35mph. That kind of wind will put wind chills down to zero and blow this dry, powdery snow around like dust. Visibilities will likely be reduced tonight and tomorrow, so keep an eye out if you're traveling.

Here's some irony for you... I have an appointment to get my wisdom teeth removed tomorrow morning. Not sure if that's still going to happen or not. If the surgeon's office is open tomorrow, I won't be posting on the blog or Facebook/Twitter for about a day or so while I'm recovering. If it's not, I'll have more updates tomorrow!

12/12 - 10am - Louisville Snow Still on Track

It's snowing in Louisville as of this writing and more of the white stuff is on the way. We'll see off and on snow showers today, but they should increase in coverage and intensity as we begin to see snow bands from Illinois cross into the region later this afternoon and evening. I'm still thinking we'll get 1-3" here in Louisville (down a little from yesterday because the cold air did not catch the precipitation fast enough last night) and some areas just to our north could see 4 inches. In contrast, areas around Minneapolis have seen over 20 inches of snow since Friday and the inflatable dome of the Minneapolis Metrodome, home of the Minnesota Vikings, has collapsed.

Winds will be a big issue later on today as they begin to increase and pick up the dry snow on the ground along with what's already falling. Visibilities could fall as this happens, so use caution if you're out and about. Side and back roads could be problematic as well due to snow cover and black ice that could have formed last night. Interstates and major roads look fine based on some of the traffic cameras I've looked at this morning, but use caution.

Saturday, December 11, 2010

12/11 - 10:45am - Louisville Snow Update

More Snow?
It's looking like our snow accumulation totals may be slightly higher here in Louisville than what I was thinking yesterday. The new 12z NAM and 6z GFS computer model runs have shifted the track of the storm slightly southward, which in turn gives us some of the heavier precipitation here in Louisville that Southern Indiana was supposed to receive. Check out the snow accumulation map from the 12z NAM below:

My latest thinking for Louisville is a 2-4" snowfall with possibly 5" just to our north. We'll watch this storm closely... the rain starts this afternoon and changes to snow early tomorrow morning. Watch out for gusty winds tomorrow and Monday!

Friday, December 10, 2010

12/10 - 12:30pm - Crazy Weather on the Way in Louisville!

I'm back home in Louisville after a long drive from Mississippi last night. My third semester at MSU is over after going through my final exams and now it's time to move on to more important things, like a potential accumulating snow here in Louisville this weekend!

The Latest
The computer forecast models have had a very difficult time trying to forecast this weekend's storm across the Upper Midwest and Ohio Valley. Earlier this week there were vast differences in where the low pressure center of this storm would track. Some models had the low moving into central Tennessee or central Kentucky before cutting northward to Ohio/West Virginia, and others had it moving into Wisconsin, Illinois, and Indiana before cutting north to the Great Lakes. The Tennessee/Kentucky track is the one that would give Louisville a snowstorm, but it appears a more northerly track will take place. The HPC's (Hydrometeorological Prediction Center) depiction of the northern track is on the right image. Luckily, for you snowlovers out there, this is not the end of our snow chances for this storm here in Kentuckiana!

As the cold air behind this storm catches up with the back end of the rain we'll see on Saturday, we may see a brief burst of wet snow on Saturday night. Then, light snow will wrap around the back end of the storm and impact us from the north on Sunday, possibly into Monday. By the time this is all said and done, I think Louisville will have 2-3" (isolated 4") of snow on the ground with lower amounts south and higher amounts north of here. The 6z GFS model seems to be picking up on these totals well and I've posted its forecast snowfall accumulation map to the left. You can click the image for a larger view if needed.

Here's what the National Weather Service in Louisville says about all of this:

Even though we have a general track somewhat ironed out now, there are a couple of details that could increase our snow totals. While the GFS/ECMWF (European)/NAM/CMC models all generally agree on a northern track to this storm, the UKMET model is still taking a more southerly track near the Ohio Valley. At this point I think it's an outlier solution, but nevertheless there is a sliver of a chance that the low could take a little jog southward and impact our snow totals. There's also a chance that a secondary low could form well to the south of the primary storm and the implications of that are pretty substantial on our snow totals. Chances for that look slim as well as most computer models either don't have it or get rid of it before it exits Texas. Again, these are just a couple little things to watch that could affect us if they come to fruition by some outside chance.

As if the snow wasn't enough, we'll also have to contend with gusty winds of 25-35mph on Sunday which will blow the drier snow around and create visibility issues. Temperatures will also plummet during the storm as a cold front comes through, meaning we'll see highs only in the 20's for Sunday and Monday here in the Metro. Factor those chilly temperatures in with the winds and you've got yourself below zero windchills. That's dangerous weather in itself... stay warm out there!

I'll be posting updates on my Facebook and Twitter accounts today if there are any updates.

Monday, December 6, 2010

12/6 - 8pm - Video from the Starkville Christmas Parade

I was able to get my hands on some video of WOBV 5's coverage of the Starkville, MS Christmas Parade that I participated in. I've edited an eleven minute highlight reel of my street reporting that you can view below. You may recognize a few familiar faces in there like meteorologist Jennifer Watson from WTVA-TV in Tupelo, MS and Jason Dunning from WCBI-TV in Columbus, MS. Both graduated from Mississippi State University's award-winning meteorology program and were real troopers for letting me stick a camera in their faces during the parade!

Sunday, December 5, 2010

12/5 - 2pm - WBBJ and Starkville Christmas Parade All in One Day!

The forecast for Jackson was fairly tame yesterday as a cold front was poised to swing through the area and bring cooler temperatures into the region. Highs could get into the 30's and lows into the teens this week, so bundle up! Check out my video from ABC 7 below:

As if waking up and going on-air early in the morning in Jackson wasn't enough yesterday, I drove back to Starkville to participate in WOBV 5's TV production of the Starkville Christmas Parade. Like last year, I interviewed participants on the floats and attendees on the street for the station and had a great time doing it! Since this year's broadcast was not live, I'll have to get a recording of the program and post it here later on in the near future.

It's final exam week here at Mississippi State, so that means I'll be heading back to Louisville for the long winter break coming up on Thursday. I'm watching a potential snowstorm that could happen up in Louisville next week like a hawk and I'll post some updates on that once I knock out these final exams.