Christmas Forecast for Kentucky

It is looking like Christmas this year is going to be pretty much par for the course.  With GFS and ECMWF both showing cold temperatures and no major storms in the area, the holiday doesn't look to be affected by nasty weather.  Save for the stray clipper that may streak in from the north with a light dusting of snow, I don't see any weather really coming our way for the 25th.  It looks to be seasonably cold with only a small chance of snow in the air.

The bigger story looks to be what happens between now and then.  After a mostly dry week this week and moderating temperatures, the weekend will turn very soggy.  Both major computer models are in step with one another showing a frontal zone setting up near the OH River this weekend.  Lots of Gulf moisture will spread northward and Kentucky will be in the prime area just south of the front to see the rainfall.  Areas of low pressure will develop along the front and move northeastward into Kentucky enhancing the rainfall throughout the weekend.  Right now it appears that we will stay on the warm side of the front, so all of the precipitation here should fall as rain.  However, just to our north a major snowstorm will be possible once again.  Some of the model data is showing 4-6" of rainfall, especially across western KY.  This axis of heaviest rainfall may set up farther east or west...it just depends on the exact position of the front.  Regardless, Kentucky is in for a very wet weekend and flooding may be the big weather story.  You can see the conveyor belt of the waves of rain coming northeastward toward Kentucky in the ECMWF model data from today:

In addition, this storm could end up becoming a travel nightmare for people looking to fly out of airports in the eastern U.S. to visit family for the holidays.  I expect that delays and cancelled flights will be a common occurrence this weekend and into early next week.

So the monster storm will come through just before Christmas, and then we go relatively calm and colder for Christmas, and then beyond that I expect winter to stay active for a little while longer.  It is not yet officially winter, so after the holidays I'll write a little bit about what January-March could hold for us this year.  I do think it's going to be interesting.

-Shawn

It's been a long time since Kentucky had an ice storm...

The GFS model is harping on another one this weekend.  The weather has turned very active this fall just as I expected.  From abnormal cold at times, to severe weather outbreaks, and snow/sleet...we've seen it all since October.  Here is how I see things playing out to end this first week of December:

Tonight the rain will start to push into Kentucky.  By tomorrow the rain may be heavy at times.  Guidance suggests that some counties could see a few inches of rain before it's all said and done.  This may create flooding issues.  The ground stays wet this time of year due to the low sun angle.  If you live near a creek or stream, or a low lying area that floods frequently, keep an eye on this!

Going into Friday the freezing line at the surface starts to move south of the Ohio River.  It will be a slow process...crossing into the Lexington area by evening.  With the freezing line obviously will come a changeover in precip. type.  I expect that rain in central KY will go over to a period of sleet during the afternoon.  There may also be some freezing rain also.  The precip. will end during the wee hours Saturday morning as snow.  The concerning part is the freezing rain possibility.  It doesn't take much ice to create a nightmare.  Here is the current forecast for ice accumulation of at least a tenth of an inch.  Notice that some areas in central Kentucky are as high as 80% chance!

This may also create an interesting situation with our schools since early Friday morning we'll just have plain rain, and the weather should deteriorate during the day while the kids are in school.  Going to be a tough call for administrators probably.

After this system departs on Saturday, the weather should go dry for a time.  This will allow those Christmas parades around central Kentucky to be squeezed in between weather systems.  However, it's going to be cold!  Some models are showing wind chill values in the 10-15°F range Saturday!  So if you're going off to see a parade take lots of clothes and blankets.

Sunday round two moves in.  This is the part that I'm most concerned about.  I just mentioned that arctic air will establish itself across Kentucky on Saturday.  With moisture once again moving into the area from the south this could be very bad news.  Warm air and precip. falling from above onto a surface that's been well below freezing could create a really bad situation with ice.  As the models are showing it right now, I expect that Sunday morning driving conditions will be very treacherous.  Keep in mind also that on Sunday, road crews are at a minimum.  Who wants to work on Sunday??  So I suggest keeping a close eye on this.  There could be lots of church cancellations on Sunday.  Let's hope that the ice doesn't accumulate to the point where we start to see tree damage and power outages.

The GFS model shows the situation well.  The blue line is the surface freezing line on this particular chart.  Notice the huge slug of precip. moving into the below freezing airmass.  Yuck.

So the bottom line is that we've got a huge mess coming up.  Rain, freezing rain, sleet, and snow are all possible at various times from Thursday-Sunday in the Bluegrass of Kentucky.  Buckle up and enjoy the ride!  And be safe out there...slow down and take your time.

-Shawn

November Going Out Like a Lion

OK, so here's how I see this winter storm shaping up for Kentucky.  Most of the action is going to happen south of I-64 and east of I-75.  So places like Corbin, Pikeville, Hazard, etc. will have to really keep an eye on this one.  I expect up to 6" of snow to fall in the mountains of eastern Kentucky through Wednesday night.

Farther west, we are looking at just a "pretty" snow here in the Bluegrass.  The type that looks really nice, but doesn't really amount to anything.

Looks like we've got a small piece of the system coming through tonight, with the main show Tuesday night into Wednesday morning.  Schools here will likely be out for the holiday before it gets rough outside.

Here is the probability of at least 2" of snow in Lexington through tomorrow night.  Notice that Lexington has a roughly 30% shot at seeing 2"...but the farther west you go the snow drops off drastically.  There will be a very sharp cutoff to the snow with this system.

There will be salt trucks running around, so watch out for them and remember to wash the car well underneath this weekend when the storm has cleared.  Ahhh...if only we could catch those tax dollars flying out the backs of those trucks...  we'd all be wealthy.

Looking down the road, December looks to remain active.  In fact, if THIS does happen, look out!

That, my friends, is a 150+ knot jet streak screaming into the Ohio Valley out of the desert southwest and IF this pattern develops it would almost certainly lead to a monster winter storm in the eastern U.S.  Kentucky would potentially be under the gun.  This is a couple weeks away so it's just for eye candy right now.

The kids are out of school Wednesday anyway, so I don't expect any impact to schools around here this week.  If you're going to eastern Kentucky to visit family for Thanksgiving you will want to watch the weather closely.

-Shawn

Severe Weather Outbreak #2 for the Fall Season in Kentucky

Update 16:45EST November 16th:

 

My concern is that this is a transitional season.  Just like March-May brings the most intense severe weather, there is another severe season that occurs in the fall of the year and we're right in the heart of it.  When you get this kind of model data coming in it really raises some eyebrows.  SPC has already upgraded from Slight Risk to Moderate Risk for a huge part of the Ohio Valley tomorrow.  It's starting to get a little concerning.

 

I'm still seeing good shear, CAPE, moisture, upper support, and favorable time of day for this system to support severe weather.  I think we will see two rounds of storms.  The WRF model shows this well.  The first wave of storms will come through early Sunday.

 

 

 

This first round of storms may bring small hail, gusty winds, and dangerous lightning with it.  After it passes through for the most part during the early afternoon, we may go quiet for a short time.  Then the wind will start to howl and as the cold front approaches from the west a more severe squall line will form and drop into the area.  This squall line looks to strike central Kentucky sometime during the evening hours.

 

 

 

This second squall line may have more severe wind associated with it.  There is also a threat for tornadoes to spin up inside the line as well.  These are the most dangerous type of tornadoes sometimes because they happen so quickly without warning and it's almost impossible to tell exactly where they will strike.  It's not like a supercell that you can easily track.  This happens and then boom it's over. 

 

I strongly recommend keeping a close eye on the weather tomorrow anywhere in the Ohio Valley. Northern Kentucky and all of Indiana and Ohio look to be the most prone for damage tomorrow.

 

-Shawn

 

Previous discussion:

 

The models are starting to indicate that yet another severe weather outbreak may be coming to the Ohio Valley.  Today’s 12Z run of the Euro model is particularly scary looking with good shear, good moisture, and favorable upper dynamics relative to this time of year.  Time of day is also good…not perfect, but good for thunderstorms.  The Euro model is showing as much as 500 joules of CAPE preceding this system Sunday night for much of Kentucky, which isn’t that shabby for November.

 

I will update the blog this weekend with more details.  For now, just file a note in the back of your mind that Sunday night could be dangerous for Kentucky and parts of surrounding states to our west as well.  Be alert!

 

CAPE values forecast off today’s 12Z European model run:

 

 

-Shawn

Halloween Thunderstorms

Update: 19:49EDT 30-October-2013

The latest run of the ECMWF model shows three distinct areas of convection ongoing as of 14:00EDT Halloween  afternoon.

The convective line in eastern Arkansas would then work northeastward into central Kentucky during the late evening.  The timing on the main push of weather looks to be between 20:00 and midnight for the Lexington area.  This doesn't mean it won't storm before then as pre-frontal cells pop up, but the main batch should come through around that time.

Following the main squall line, there may be a second line come through overnight as the airmass driving this system plows through the state.

Ahead of this system, it's going to be very windy tomorrow during the day.  A Wind Advisory is posted currently by the NWS for most of the state.  The ECMWF model predicts sustained winds of 18-24 MPH!  This should mean that gusts will exceed 40 at times.  You should tie down trash cans, loose outdoor furniture, jack-o-lanterns, and anything else that you don't want to blow away tomorrow.

Additionally, there is still a high-end Slight  Risk of severe weather posted for all of Kentucky roughly west of I-75 tomorrow.  Tornado spin-ups along the squall line are a possibility.  If any tornadoes do spin up, these will be the type that are very hard to detect with radar and will hit quickly.  These types of tornadoes have a much smaller warning time.  Therefore, it is critical that even if a Severe T-storm Warning is issued for your location tomorrow, you should still take shelter (as always) as if it were a Tornado Warning instead.

Obviously, most towns have changed trick-or-treat to Friday to protect the children in case of severe weather moving in sooner.  I think this is a great call.  Safety first!

Previous discussion follows:


-Shawn


Right on cue, the wild ride I talked about in my last update has arrived.  We had some of the hottest weather of the year early in October, and that went straight into winter-like temps this past week with lows below freezing and highs that didn't get out of the 40s.  We even saw a few snow flakes mixed in with plain rain for a brief time that did not accumulate at all but for some it was neat to see.

As we head into the final week of the month the roller coaster continues.  Temps early this week will moderate back to normal with highs in the 60s.  The weather actually looks to be quite pleasant, so enjoy it!  By Wednesday the next weather system will start to draw closer and by Halloween it will be upon Kentucky with rain and thunderstorms likely.  This is not looking like a good forecast for treat-or-treat at all according to the GFS model.

The GFS model brings the heavy part of the storm in during the evening Thursday and pushes it through during the night.  It shows a 110 knot jet streak overhead so there will be some decent upper air support.  RH values look to be decent for this time of year also.  The real question will be how much instability can we achieve during the day Thursday?

If we get some good insolation and increase in instability we could potentially see a round of stronger storms push through.  The tornado threat at this point looks low, but we will have to watch model trends over the next couple of days to see how this evolves.  The Storm Prediction Center currently has areas just to our south highlighted for severe weather but they do mention that Kentucky could potentially end up being included in the outlook area in later forecasts.  Also, it was looking like a flooding threat from heavy rains might occur but now that is looking less likely.

The ECMWF model is slower and brings the main push of weather through overnight Thursday into Friday morning.  As a result, it shows even less instability and meager CAPE values of a few hundred joules per KG at best.

If this model verifies, the threat of severe weather would be much lower.  It would be possible that some areas in central KY might possibly squeeze in some dry weather during the early evening for trick-or-treat before the rain hits.

It'll take a couple more runs before we can put a finger on the exact timing of this storm system for Kentucky.  The bottom line right now is this:  beautiful fall weather tomorrow will slowly degrade this week and turn into rain by Thursday.  Cooler air will once again spill into Kentucky next weekend behind the cold front and we'll start the cycle all over again.


-Shawn

Cooler Weather is Here to Stay

If Wednesday is "hump day", then this week is "hump week" as we are now firmly into the middle of October.  This, being a transition month, is usually one of the most unpredictable months of the year.  You can have snow or tornadoes, sub-freezing air or mid-80s, sunshine and drought or flooding in any given Kentucky October.  So far in 2013, October has been fairly nice though and for that many of us are thankful.  This is about to change now, and the cold air of Fall is upon us as the sun is approaching the Tropic of Capricorn.

This year has been an odd one, with every single month except February being cooler than average.  It's also been rainy this year with no dry months, let alone drought.  The reason for this is because a blocking pattern established itself in the northern latitudes that resulted in a trough controlling the weather in the eastern U.S. for most of the year.  We saw that trough finally break up in September which is why we had the warmest weather of the year in September and the first week of October.  Interestingly, the GFS model is predicting that the trough is going to return now.  It looks as though the eastern U.S. is going back into the northwesterly flow possibly for the rest of October.

What does this mean for Kentucky?  Well, as you can see on the (clickable) image above, the jet stream is going to take a big dip and when that happens, you get colder air moving in.  This image is valid Thursday the 24th.  The trough is actually going to move in tomorrow with cooler air...but the model is predicting that the trough will actually linger and then become sharper next week.  By Thursday the 24th, Kentucky is firmly in the base of the trough and this will likely bring our coldest temps of the season with frost being likely.

We will NOT have a good shot at snowflakes, contrary to what a certain TV meteorologist in Lexington will start harping on daily now until May.  But we will see showery weather and colder air become more common now going toward November.

It's time to get out the jackets and coats.  And as bad as I hate it...my utility bill is likely going to start going up now because the thermostat will soon get flipped to the "heat" setting.


-Shawn

October Weather in Kentucky Looks More Stormy

My meteorology friends and I have been using one word to describe 2013: boring.  But I suppose that’s a good thing when you consider the shear lack of tornado outbreaks and big severe weather outbreaks across the nation this year.  Here in the Ohio Valley region we’ve spent most of the year locked into a blocking pattern that has kept the flow mostly northwesterly.  As a result, we’ve had above normal precipitation and below normal temperatures in every single month this year, minus February.

 

That’s all about to change, however.  In my last write-up I talked about how this consistency in the pattern is what leads me to believe it will break up soon.  Looking at the latest model data, that may be exactly what’s about to happen.  The jet stream is starting to move around more now and going into October the GFS model is predicting the jet to go wild.  A very wavy looking pattern, which we call a “meridional flow” pattern, is predicted to take shape in the coming weeks.  When this happens, it shakes up the weather nation-wide.

 

 

I expect that the first truly cold air of the season is coming to the Rocky Mountains soon.  We may hear the first echoes of the “S-word” mentioned by national TV weather personalities as some huge troughs begin to dig into the western U.S.  Here in the Ohio Valley, Kentuckians can expect more variability in the weather with potential episodes of heavy rain and more frequent shots of colder air moving in.

 

Because of the cool, wet summer we just experienced I’ve been using 2004 as a good analog year to compare to when looking at what may be coming for the end of this year.  This might not turn out to be a good year to use after all.  In 2004 the 70s and 80s that we saw all summer continued through October.  What was labeled as “cool” in July became “warm” by the time we were deep into fall.  Winter ended up being mild overall, with one historic snowstorm around Christmas that mainly affected the Louisville area with a couple feet of snow, and another cold snap in late January, but otherwise temperate and rather dry.  This year is starting to follow a different course already with the cool air of summer looking like it will turn into cold air sooner.  You certainly cannot predict winter accurately from months away and I will not try.  But the overall pattern this year will likely be colder and snowier than what we ended up seeing the last time we had a cool summer.

 

It should be fun to watch this play out.  In the meantime, as the growing season comes to and end now we’ll all be on the lookout for that first frost of the season.  If the GFS computer model is on to something, we might not have to wait too much longer.

 

 

-Shawn

Some Early Thoughts on Winter 2013 - 2014

 

The weather pattern all year has been one that features a lot of blocking across Canada which has largely kept the eastern U.S. in a trough.  As a result, the eastern part of the nation has been cool and wet, while the western part of the nation has baked.  The consistency of this pattern for the first 8 solid months of the year has been pretty amazing.  The last cool summer similar to this was nine years ago, when the Lexington official reporting station never hit 90°F the entire year.

 

Summer 2013 is starting to wind down now.  Meteorological autumn begins in just 20 days.  This has led many including myself to start wondering what the end of the year may bring.  If this pattern that has been locked in all year were to remain in place going into late autumn and early winter, we could be looking at ferocious winter weather with snow and very cold weather being likely.  In fact, the summer I mentioned earlier resulted in a massive snowstorm just three days before Christmas 2004 in which Louisville saw two feet of snow and the Lexington area got in on some of the action as well.  So with 2013 going the way of the unusually cool and wet summers it does make you wonder what could by lying ahead for us.

 

On the other hand the amazing consistency of the pattern we’ve seen is also what makes me think it will break up soon.  It’s just a matter of time until the blocking breaks up and allows the jet stream to start moving around again.  Interestingly, this is what the GFS model is currently showing for the second half of August.  It lifts the jet northward, and takes the flow across the United States into a zonal setup.  Basically, this just means that you don’t have huge ridges and troughs…the flow is simply west to east across the nation.  This would result in a more stagnant airmass, as well as an increase in temperatures for us and a lack of rainfall compared to what we have been seeing.

 

 

The question of course becomes:  Is this a temporary switch to more average summer weather at the very end of summer or is this the beginning of the next major pattern flip?  That is the huge question because again, if the current pattern were to take us into winter we’d have big problems.  But if this switch at the end of August is the beginning of an overall pattern flop, then winter 2013-2014 will be anybody’s guess.  Time will tell and of course I’ll be watching for signs.  In the meantime, it appears that summer is going to give us one final attempt at mustering up some hot and humid air to close out the season for 2013.

 

 

-Shawn

Cool and Wet Summer Continues in Kentucky

June finished with over 7” of rain in Lawrenceburg, making it clearly above average.  So far, we are 5 days into July and we’ve already seen over 3.5” of rain and there is more in the forecast for the upcoming weekend, so you can already label July above average too.  So…out of the first 7 months of the year, 6 of them have seen above average amounts of precipitation.  That is why the grass still looks green, trees are growing rapidly, and the temperatures here have only passed 90°F on one day the entire year.

 

This is a total reversal of this time last year, in which we were baking in 103°F temperatures with heat indices into the 115°F range.  However, July 2012, despite the heat, did feature a lot of rainfall.

 

So is this going to be the rule for summer 2013?  It continues to look that way.  Next week we will probably see warmer weather.  Temperatures in the 85-90 degree range will be common I think, and areas that stay out of the scattered thunderstorms will have a chance to pass the 90°F mark.  However, it looks to be short lived.  The model data is predicting that the “heat bubble” will retrograde back to the western part of the nation again, which will open the gates for a large trough to once again take over in the east.  This should result in a continuation of the relatively mild and wet summer that we’ve been seeing so far in the Ohio Valley.

 

 

I still do not expect July to finish as a hot month.  The large amounts of rain we’ve seen this year have caused ground water levels to be high and vegetation to be green and moist and this will keep mitigate the heat.  And with the flow being mostly from the northwest we won’t see the tropical air mass down south invade this area.  So I look for a July that is relatively cool compared to average and wet.  What about August, the hottest month of the year?  Time will tell, but there is no data currently suggesting that a reversal will take place.  Summer 2013 will probably go down as one of the coolest and wettest on record.

 

Some farmers say that too much rain is as bad as not enough rain because you can’t get down into the field to work the crops.  My hope is that the pattern lets up enough from time to time to allow the soil to drain some.  I have also noticed a huge increase in mosquito activity and I’ve read that in the western part of the state there are areas that are being dusted via aircraft to try and control mosquitoes.  So there is clearly good and bad with both drought and wet weather.  It seems there is no such thing as “normal” anymore in Kentucky.  This summer, though, is one for the books if you hate hot and oppressive summer weather.

 

 

-Shawn

Kentucky Speedway Weather Forecast for NASCAR Weekend

Update (13:06EDT 26-June-2013):

It is gametime.  It now appears that central KY is the prime spot for severe weather across the nation today.  Lexington, KY is the center of the tornado threat zone (5%).  Widespread severe weather and high wind will be possible across southern IN, most of KY, and parts of TN before nightfall.  Be prepared for flash flooding, dangerous lightning, and large hail also.  It's about to get ugly.

Update (14:01EDT 25-June-2013):

The Storm Prediction Center has just upgraded most of Kentucky to it's 30% probability range for tomorrow.  The ingredients are starting to come together nicely for a severe weather outbreak Wednesday evening into early Thursday morning.  Tornadoes will be possible, but large hail and high wind will be more likely.  This activity may affect all areas in and around Kentucky Speedway.  People camping should stay alert and keep the NOAA weather radios nearby at all times Wednesday and Thursday.

Previous discussion:

Race fans showing up at Kentucky Speedway on Thursday will likely need to bring the ponchos and umbrellas.  It appears that a weather system will drop in from the north and bring a good chance for thunderstorms to the region.  Some of the rain could be heavy.  While every place won’t see rain all day, I would prepare for a wet Thursday.

The rest of the NASCAR weekend looks better with smaller chances for storms, but still a chance for storms nonetheless.  Outside of thunderstorms temperatures will be very warm with highs close to 90.  If we see sunshine most of the day, the green flag weather will be uncomfortably hot Saturday.  Hopefully there’ll be a mix of clouds to keep the heat down this weekend.

Overall it looks like about a  70%  shot at rain on Thursday, and then more of a 30% shot of rain Friday and Saturday.  We could see another MCS drop in late Saturday night or Sunday morning with a re-enforcing blow of thunderstorms.

Stay safe and enjoy the weekend.  I’ll be watching from the couch this year.

-Shawn

Derecho?

A “derecho” is a large meso-scale convective weather system that usually takes on the shape of a boomerang and can be hundreds of miles wide.  They will typically advance at high speed for hundreds of miles across many states spreading very high wind out ahead of the edge of the line.  The Ohio Valley commonly sees these in the summer months, with lots of wind damage as a result.

 

The computer modeling has been hinting for days now that a storm of this type will form near Iowa and then head southeast into the middle and/or upper Ohio Valley Wednesday night into Thursday morning.  The first concern is: will this storm actually form as predicted?  There are a couple of points that might prevent this.  Dewpoints are only mildly high with readings in the upper 60s and low 70s and these may fall slightly as we head into this afternoon.  Secondly, upper flow is not particularly strong in this area.  So we’ll have to wait until afternoon and see if this derecho actually does form.  If it does, the second concern obviously will be its path.  What path will it take?

 

Currently, the Storm Prediction Center is thinking that the storm will move largely eastward, and will affect Indiana and into Ohio and then West Virginia.  There is an outside chance that it could track slightly farther southward which would pull northern Kentucky into the mix as well.  Here is the current outlook from SPC for the possibility of wind damage tonight:

 

 

None of the high resolution models are currently showing the derecho affecting Kentucky.  What they do show is a line of storms connected to the derecho back-building down the Ohio River.  This line of storms would then sweep across Kentucky late tonight and would pose a lesser, but still possibly severe, threat to central Kentucky.  The NAM-WRF model shows this well:

 

 

Everyone along and north of I-64 needs to pay special attention to the weather conditions tonight.  This has the potential to be a very damaging event for a great number of people.  NOAA weather radio is the best way to receive warnings and watches.  If you use a smartphone, I have found Weatherbug to be the best app.  The NWS websites are also the best places for weather forecasts and info.  http://www.weather.gov/louisville

 

 

-Shawn

Kentucky Drought in Summer 2013?

The thing that has stood out to me so far in 2013 is the amazing consistency of the overall weather pattern we’ve been locked into here in the Ohio Valley.  Typically, the weather varies greatly from month to month and from season to season here in Kentucky.  What we’ve seen since January has been quite the opposite.

 

Temperature is one part of the equation but precipitation is arguably the most important statistic for most people.  Whether you have agricultural interests, or sporting interests, or are an outdoor event planner, the precipitation stats are what you are really after.  Check out where we are so far in 2013:

 

 

The average precipitation stats come from Lexington, KY because that is the nearest official reporting station for National Weather Service records and the received precipitation stats come from my weather station in Lawrenceburg, KY.  However, only about 17 miles separates the two sites as the crow flies so bear with me for the sake of conversation here.  Look at the amazing consistency we have seen.  January, March, and April were all roughly one and a quarter inches above average.  February was the only month with below average precipitation so far this year.  May still has a week to go with plenty of rain in the forecast so it’s reasonable to assume that we’ll finish the month near or above average again.

 

With almost five months in the books for 2013 and this wet pattern being so persistent, the reasonable forecast for summer would be to predict a continuation of wet weather unless some data strongly suggests otherwise.  Farmers will be happy to know that at this point in time that’s not the case.  It does not look like a drought will set up this summer.  The first half of June, which had been looking to come in hot and dry, is now beginning to look cooler and possibly wetter as the computer models are starting to get a hold on how things will evolve.  The official forecast for the critical growing months of July, August, and September calls for “equal chances”.  In short, this means that the forecasters cannot see any reason why drought would set up in this area, nor do they see any data suggesting abnormally wet conditions.  Basically, one can look at it as if average weather for the time of year can be expected.  Take a look:

 

 

In the past several years we’ve seen a lot of hot summers and dry conditions.  It makes sense that we’re due for a wetter and cooler summer overall and the data is supporting that idea right now.  That’s not to say that we’re going to have another 2004 in which we never touched 90 degrees all year long.  But I just don’t see the oppressive and consistent heat setting in this year.  I also don’t think we will go into a serious drought this year.  If we continue on our current weather pattern it would make for a pretty awesome growing season for those with agricultural interests.  That is, if the rain doesn’t come in the form of severe weather.

 

Enjoy your Memorial Day weekend.  The weather looks fantastic!

 

 

-Shawn

Severe Weather Odds for Central Kentucky

Update (14:08EDT 22-May-2013):

While SPC does still have most of KY in the Slight Risk zone for severe weather this afternoon, I don't feel that coverage is going to be anything like what we saw yesterday.  Southern and eastern KY got hit hard yesterday. Today the airmass simply is not as unstable.  Also, we are blanketed by a lot more cloudcover.  I don't see storms blowing up across the state today.  There may be a few isolated storms or rain showers, but that's about it for the next several hours at least.  

For this afternoon, most of the severe weather will likely be confined to areas north and east of Kentucky....from Indiana into New York.

The front will pass through on Thursday and Kentucky might possibly see more storms again with that passage.  I'll keep an eye on it.

-Shawn



Update (22:27EDT 21-May-2013):

Round two is about to push into central Kentucky over the next couple of hours.  This batch looked very healthy in western Kentucky but it is now weakening due to loss of solar energy and because the atmosphere here is still recovering from the first wave.  So I don't expect any severe weather overnight in central Kentucky.  Just garden variety thundershowers.

A low level jet is anticipated to ramp up during the morning hours and we could potentially see round three of thunderstorms moving into the area early Wednesday.  My opinion is that this is very questionable right now, but the modeling isn't helping much at this point so it should be mentioned at least as a possibility.  Wednesday afternoon if we see more sunshine we could have another more severe round of storms blow up.  We will watch that closely tomorrow.

For tonight, I think most of us can sleep easy but keep those NOAA radios on alert mode at all times to be safe.


-Shawn



Update (12:33EDT 21-May-2013):

I looked over the 12Z model data.  Hi-Res NAM model looks a little less likely to me with only isolated supercell storms blowing up in this highly unstable airmass this afternoon.  Taken verbatim, it shows one massive storm near Frankfort, KY and another near Campbellsville, KY this afternoon...then grows these two isolated supercells into a larger MCS this evening.  What I think is more likely is the scenario offered by the WRF model out of St. Louis NWS office.  Here is a look at it:

The reason I like this solution a little better is because we currently have a cluster of storms trying to get going in western Kentucky and the outflow boundaries left behind from earlier dying convection this morning would seem to be a great way for the current storms to go upscale and create explosive convective development in the Bowling Green, KY area this afternoon.

So let me be clear that the forecast for today is very challenging.  There are so many cards on the table.  But..if I had to make a forecast I would say that with clearing skies now in the Bluegrass part of the state, instability is going to be insane and with a cluster of storms trying to get going now in the western part of the state we may just have the trigger we need to cause storms to rupture this afternoon.  I think that south-central KY stands the best chance of seeing storms today.  The Bluegrass will likely get some activity...but I think it'll be later in the day.  Soundings are showing huge CAPE numbers, the lifted index numbers are very low (around -10!) and we have a lot of moisture to feed on.  It's just a matter of a trigger and I think that trigger currently lies in west KY.

Keep in mind that while we do not have the tornado threat that Oklahoma had yesterday, we still could see damaging hail and winds from any storms that manage to blow up.  Fortunately, the wind fields look less than favorable today for us to see tornadoes.  So that isn't a huge threat.  But excessive rain will cause possible flash floods under these storms and flash flooding is the #1 killer of weather.  Did you know that?  Also, the lightning should be intense with these storms and you also have the hail and wind threat.

I think SPC should extend the Slight Risk zone farther east to include the Lexington and Somerset areas.  They will be updating within the next hour and we'll see if they choose to do that or not.

Unfortunately for Moore, OK...they are seeing more severe weather again today.  Poor folks...

-Shawn

When the 12Z data finishes coming in over the next 2 hours I will take a good look at it and post my thoughts on how this evening will unfold for Kentucky.  We’ve all seen the destruction left behind in Oklahoma.  I was there in 1999 to see that damage first hand.  I went down to the Storm Prediction Center office, and the word floating around unofficially was that if there was such thing as F-6 on the scale, that tornado would have been F-6.  Well, this 2013 May event in Moore, OK hit pretty much the same area and from the pictures I have seen it was equally as bad as 1999.  Please keep those folks in your prayers.

An update for Kentucky is coming soon…stay tuned.

-Shawn

Kentucky Derby Looks Wet

It looks like the weather for KY Oaks will be nice.  There is a small chance of a shower or two, but I think that the day will mostly be dry in Louisville, as well as in all areas of Kentucky along and east of I-65.

The computer modeling is pretty locked onto the idea of swinging the axis of rain eastward into the state on Saturday, however.  It looks like the entire swath of rain and embedded lightning strikes here and there will spin around the gyre and so the Louisville area will see a good soaking leading up to, and during, the KY Derby this year.  If you are a gambler, it's time to put your money on the horse that's a good "mudder".

Here's the depiction from the latest Hi-Resolution NAM model.  Notice the axis of rain directly over central Kentucky:

-Shawn

May Flowers or May Showers?

The outlook for April worked out great.  Highs in the 50s and 60s were common most days, and it turned out to be a wet month.  Let me give a few thoughts about May.  They say April showers bring May flowers but for 2013 we’re probably just looking at more showers.

 

The weather for Derby weekend is looking iffy.  On one hand you’ve got the GFS model which tries to hold a cut-off low out in Missouri and that would mean showers and storms staying just west of I-65 through Saturday.  On the other hand you’ve got the ECMWF model bringing the low closer to Kentucky and the resulting rain moves into our area for Saturday.  Both models are pretty similar, but in this case 100 miles is going to make the difference.  It’s going to be a very tough forecast.  Will the Kentucky Derby run in the rain or on a dry track?  That is anyone’s guess.  These pesky cut-off low pressure systems spin over an area for days on end and really wreak havoc with everything.  One thing that’s pretty sure is that the weather will be unsettled this weekend with chances for rain through at least Monday.

 

As we head into mid-May, signs are pointing to more upper level blocking occurring in Canada.  Unfortunately this means a continuation of northerly flow and cooler air.  It looks to me like the weather we’ve seen in April will carry us into most of May as well.  We normally start seeing a big warm-up in May with days in the 80s being common.  I don’t think that’s going to be the norm this year.  I think a generally cool and wet pattern is going to rule the month.  Those who enjoy outdoor activities won’t be very excited about that forecast, but agricultural interests should be happy for frequent rainfall and mild temperatures.  This may turn out to be a pretty good growing season.  The bottom line is that we’re going to have to hang onto the jackets a little longer than usual this year.

 

 

 

 

Shawn

 

Kentucky Derby Forecast

Well, we are now a week away from KY Oaks and KY Derby action in Louisville, Kentucky.  Let’s take a look at what the weather may have in store…because the weather is everything for this event.

 

For the past couple of days, the GFS model has been consistent in showing an upper air pattern developing by Thursday that would create a lot of blocking across North America.   This, in turn, would cause a storm system moving through the Ohio Valley sometime around Thursday to put the brakes on and stall out.  We could potentially see a lot of rainfall and possible flooding issues with this system as it moves through on Thursday. 

 

The parent low is then forecast to get caught up in the blocking and become cut-off from the main flow.  Cut-off lows are horrible things…they spin over the area for days on end and bring clouds, showers, and generally nasty weather.  It is unfortunately starting to appear that this is exactly what’s going to happen next weekend.

 

Check out the brand new GFS run hot off the press.  It shows the cold backlash of air coming in on Friday behind the cold front, the day of KY Oaks action, with high temperatures topping out in the 40s!  Yuck!

 

 

 

As the low becomes cut-off from the main flow, it will spin over the area throughout the Derby weekend.  Here is the GFS forecast for Saturday evening.  Notice that we’re in the 40s for a high on Saturday as well, with WET conditions area-wide.

 

 

 

For the thousands of fans planning to attend this year, the weather forecast is a nightmare.  For the jockeys and horses entering the races, it’s not much better.  We haven’t seen frozen precipitation on Derby Day since 1989.  This year there is a much better than average chance that we could put some frozen precip. on the board for Derby Day.

 

I will continue to watch this forecast evolve over the next few days, but for now you can plan on the Kentucky Derby weather being down right AWFUL this year.

 

 

-Shawn

 

Tornadoes Possible in Kentucky

Good afternoon.  A severe weather outbreak is occurring now and will continue to get worse as we head into the evening hours.  A powerful cold front is running into a warm and moist airmass in the Ohio Valley and wind parameters are favorable for bowing structures and tornado spin-ups inside the squall line.  It appears that this squall line will move across the area this evening and tonight and we will probably see damage along its path.  The current model data is pretty impressive looking with this line later today.

 

Here is the current outlook from the Storm Prediction Center.   Notice that areas west of I-65 are in the Moderate Risk zone.

 

 

 

Based upon the latest computer model data here is what I think will happen..

 

Areas out to our west around Paducah, KY will see the greatest chance of severe weather.  Western Kentucky will begin to be affected by the squall line as early as 18:00 tonight.  As the line moves eastward, it should reach the Elizabethtown area by around 22:00 tonight.  I think that it will maintain its severe nature as it moves eastward, and based upon forecast soundings I would say that a few tornadoes will occur with this activity.  Wind damage will be fairly widespread out in western KY, southern IN, and western TN.  By midnight (0:00EDT Friday) the line will advance into the Bluegrass of Kentucky and by this time it will be in a weakening phase.  All of the major computer models drastically decrease the severity of the squall line by the time it reaches the Lexington, KY area just after midnight.

 

There will still be isolated wind damage reports in central and eastern KY…but by far the worst of this storm will occur in western KY.  The rain shield will move across central KY Friday and should clear the area by noon on Friday.  It may be that flooding issues will be the worst part of this storm for the Bluegrass and also eastern KY.  Remember…flash flooding is the #1 killer of severe weather!

 

If I lived west of I-65 I would take the time now to prepare for possible tornadoes and wind damage.  Have a plan ready for your family in case you take a direct hit.  Remember to keep a NOAA weather radio on alert mode to keep you updated on the latest warnings.

 

Here is a graphic from the NWS office in Louisville, KY showing their forecast timing on when this line of storms should move into your area.

 

 

 

I will update via Twitter for the remainder of the afternoon and evening.  @WxinKY

 

 

-Shawn

More Storms Coming

Looks like another round of storms this afternoon.  The HI-Res NAM wants to blow the area up again, the visible sat. channel is showing good sunshine along I-65, and SPC is monitoring for a possible watch and upgrade back to Slight Risk for us.  I’d say in a couple more hours we’ll see round 2 pop off in this soupy airmass with dewpoints in the 60s.  All kinds of outflow boundaries are left behind also.  Pretty textbook environment for more activity here today.

 

Question will be how far north and east of I-65 will it occur.  We’re still socked into left over cloudiness from this morning’s convection here in Frankfort.  Might be a close call for Frankfort and Lawrenceburg.  Right now I think that areas along and west of I-65 will see the best coverage of storms.  The Bluegrass counties in and around Lexington may possibly see storms drift into the area from the southwest this afternoon, or if we see enough clearing we could possibly get new convection to form here.  Any storms that do form will be capable of large hail once again, because the air aloft is very cold at a low altitude. 

 

Keep your eyes peeled this afternoon and evening. 

 

The thinking for Friday at this point is that the squall line will be severe in western Kentucky Thursday night, but will be in a weakening phase on Friday morning when it rolls into the Lexington area.  Strong storms likely…but severe weather and damage isn’t looking like a sure bet here in central KY at this point.

 

Here’s an image courtesy of my friend Brian Goode at WAVE-TV from last night’s hailstorm near Louisville.  I can assure you that the people under the storm were not smiling.  J

 

 

Shawn