7/22 - 10:30pm CDT - Heat Cranks Up in West Tennessee

A few showers at 3:25pm today

Some showers and downpours did make it a little further north than expected today across West Tennessee. Last night's model guidance and thinking was that any of these scattered "pop-up" showers would stay mostly south of the Mississippi border, but a complex of storms moved a bit further north than expected out of Alabama into Middle Tennessee. This complex of storms brought with it a small boundary in the atmosphere that helped get these widely scattered showers going over portions of West Tennessee this afternoon. These have all since faded away and the region should have a stretch of hot and mostly clear weather through at least the middle of the week. Humidity will be on the increase as temperatures get into the upper 90's, so expect some dangerous heat index values well over 100 degrees. Storm chances look like they will now be increasing toward the end of the week as a front drops from the south but temperatures still appear to be heading toward the triple digits since this front likely won't make it far enough south to pass through.

My weathercast from last night's 10pm news on WBBJ in Jackson is available to watch below.

7/15 - 7pm CDT - The Heat Returns!

A few showers are ongoing across West Tennnessee right now, but this is quite a bit less than what was expected today. Dry air rotating around a area of high pressure has moved into the region because this high has nudged a bit further westward than originally forecast. This means that a majority of the shower activity has stayed west of the Mississippi River, but a couple thundershowers could still pop up before sunset. These should mostly dissipate before the overnight hours.

Heat and humidity are on their way back as a large ridge of high pressure moves eastward over the next few days. This should surpress storm chances a little bit, but not entirely because temperatures aloft will still be a little cool. This heat at the surface and the slightly cool air aloft should create the typical "summertime pop-up storm" environment that we're used to seeing in the afternoons this time of year. Temperatures underneath this ridge of high pressure should be in the lower to middle 90's in West Tenneessee and middle 90's until Wednesday in Kentuckiana. A front dropping south on Thursday will trigger higher rain chances in both Kentuckiana and West Tenneessee and there could be some slightly cooler temperatures behind the front for Kentuckiana. Things look to remain hot all week long in West Tennessee!

I'm in Jackson, TN right now getting ready for the 10 O'Clock news on WBBJ this evening before going back to Louisville tomorrow. Check out my Hokey Weather Fact from last night's show on the left and be sure to tune in to WBBJ tonight at 10 for a new one!

 

7/7 - 10:30pm - Massive Heat Wave Ends with Storms

Today capped off the longest, hottest stretch of weather in Louisville that most people can remember. Today's 106° high at Louisville International Airport was the hottest it's been since July 14th, 1936 when it got to 107°. That temperature is Louisville's all-time record high and if we didn't have as many clouds as we did this afternoon in the city we would have met or broken it. This ends nine days of 100°+ weather, which is the third-longest stretch of triple digits ever recorded according to NWS Louisville.

Storms that will develop tomorrow will be ushering in cooler temperatures, which is welcome news! The bad part is that some of these storms may be severe due to the incredible amount of energy they'll have at their disposal from all the heat. Temperatures in the mid 90's tomorrow with sunshine and high humidity will power an awful lot of instability, or the tendency for air parcels to rise and create thunderstorms. A cold front sinking down from the north that will be stalling out once it passes just to our south will be the focus for storm chances starting tomorrow in the early afternoon in Louisville and lasting through Monday morning.

The main threats from these storms will be wind and hail, but there could also be a threat for some rotating storms too. While winds don't look favorable for any sort of big tornado problems tomorrow, a couple of these rotating storms may get just enough juice to put down a brief spin-up. EHI values in the adjacent image take into account both instability and helicity, which is a product of wind shear. The elevated values you see are powered mostly by instability and just a little bit of helicity, so again, winds aren't that favorable here. The Louisville area is no stranger to summertime tornadoes as you may remember a series of four of them that touched down in late June of last year.

Given the chances for some severe wind and hail tomorrow, the Storm Prediction Center has issued a 15% Slight Risk area for Kentucky. A better chance for severe weather (30%) exists closer to the East Coast where upper-level winds will be stronger as a trough digs down a bit into that area.

7/5 - 11:30pm - Louisville Urban Heat Island This Week

It goes without saying that it's been incredibly hot this week in Louisville. This is all thanks to an expansive ridge of high pressure over the center of the country. High temperatures have been record-breaking every day this week except Tuesday when the high at the airport was below 100. This stretch of triple digit temperatures dates back to June 28th and there appear to be at least two more days of 100-plus weather ahead. The urban heat island effect, which causes temperatures in concrete and asphalt-filled urban areas to be higher than more vegetated suburban and rural areas, has been pretty apparent with the extreme heat. Temperature readings at Louisville International Airport have been consistently higher than other observation sites within the city and this is easy to see when comparing the high and low temperatures for each day this week with surrounding stations. Below you'll find the high and low temperatures for each day of the week so far at Louisville International Airport (KSDF), a personal weather station in Shively (West Louisville), Bowman Field, and a personal weather station in Fisherville (East Louisville):

Thursday July 5th

Louisville Airport 104/78 | Shively 100/72 | Bowman 102/78 | Fisherville 98/72

Wednesday July 4th

Louisville Airport 102/76 | Shively 101/76 | Bowman 99/76 | Fisherville 97/69

Tuesday July 3rd

Louisville Airport 97/73 | Shively 97/73 | Bowman 96/72 | Fisherville 93/67

Monday July 2nd

Louisville Airport 100/73 | Shively 99/73 | Bowman 99/71 | Fisherville 96/67

Sunday July 1st

Louisville Airport 103/74 | Shively 102/75 | Bowman 101/72 | Fisherville 99/70

I've sorted the data above from most urban (the airport) to least urban (Fisherville), so it's not hard to put together that temperatures generally decrease as you get further away from the dense center of Louisville. The Fisherville observation station is located in a valley in the eastern portion of the county, so the low temperatures each morning are a bit cooler than they would be otherwise due to cool air settling into the valley at night. High temperatures at this station shouldn't be affected by the valley and this checks out because I've been keeping an eye on the observations in Shelbyville, which is down the street from Fisherville, so to say. This warmth due to the urban heat island near the airport is significant because this is where the official temperatures for the city are taken. If it's 100 degrees at the airport, the rest of the city is probably seeing temperatures a degree or two cooler.

This difference in temperature between the airport and the rest of the city was the focus of some research I published in April for a class at Mississippi State University. I used quite a bit of historical data to figure out how much the urban heat island "distorts" the temperatures at the airport. Go check out my research by clicking this link to a blog post I penned earlier this year.

 

6/19 - 3:15pm - The Last Day of Spring

Tomorrow marks the first day of summer as the summer solstice occurs at 7:09pm EDT. The summer solstice put simply is the longest day of the year in the northern hemisphere because the north pole is tilted toward the sun. The sun will be directly overhead at 23.5 degrees north latitude or the Tropic of Cancer, located on a line that runs between Cuba and Florida. Meteorological summer, the three month period that meteorologists consider summertime in weather terms, started on June 1st with hurricane season.

I'll tell you that it's been pretty warm in Europe over the last couple of weeks. My family and I enjoyed a very nice trip around the Mediterranean Sea and traveled to Italy, Croatia, Turkey, Monaco, and Spain. I'm still a little jet-lagged from the marathon flight between Barcelona and Philadelphia we were on Sunday, but I'm slowly acclimating to Eastern Time again. Crazily enough, a tornado touched down in Venice, Italy last week well after we had left port on our ship. Thankfully there were no injuries, but some damage was done in a place that rarely sees tornadoes. Read more about what happened here.

The heat we had in Europe followed me home to Louisville (not meteorologically of course) and now we're experiencing quite a heat wave. High temperatures are expected to be at or above 90 degrees for most of the week here, but we may get a small break on Thursday night/Friday morning thanks to a cold front approaching the area. This thing may run out of steam just as it's nearing the Ohio River late on Thursday so rainfall chances could be slim with this.

If it continues to chug along further south than expcted we could have some storms around during this timeframe. Areas in Western Kentucky and Northwest Tennessee do need the rain, but unfortunately this won't be enough (if it happens at all) to assuage much of the drought in that region. The US Drought Monitor from the University of Nebraska-Lincoln has portions of this area under a moderate to severe drought. 

In just four days I'll be heading to Denver to join Storm Chasing Adventure Tours for one more week of storm chasing this year. It's been a whirlwind of a summer break for me so far with three weeks of storm chasing and two weeks of travel in Europe under my belt, but I'm definitely excited for another week of chasing! It looks like storms may fire up early to mid next week in the Dakotas, Nebraska, and Wyoming as an upper-level disturbance inches onshore from the Pacific. It's a bit far out for specifics at this point, but I think moisture and upper-level support during this time might be decent if this disturbance comes onshore in time. The limiting factor may be capping (warm air) aloft since temperatures may be a little high up there. It'll be interesting to see how this develops over the course of the week!

Be sure to follow me on Twitter and Facebook so that you'll be ready to receive my instant storm chasing updates next week!

 

4/28 - 4:45pm - Hot Weather, Fun Show at WBBJ!

Today marks my last show at WBBJ until August when I come back from my college summer break. And boy what a fitting show it was. Of course the weather is going to be hot and muggy through next week with pretty consistent small daily storm chances (each day except Wednesday). A pesky frontal boundary sticking around the region for a few days before eventually lifting northward will be the culprit for these pop-up showers and storms. You can check out the video from this morning's weathercast below. The big show today was an interview by Myles Savage, the lead singer from the Platters, this morning on our show. He gave a fun and spirited performance that none of us in the studio will ever forget! The video of his interview is below my weathercast. Enjoy!

Just ONE WEEK until my first three weeks of storm chasing begins in the Plains!

4/25 - 12:45pm - A Hot Week in Starkville

The rest of the week in Starkville is going to be hot by most standards. Today through the end of the workweek will see highs in the mid 80's. Sunshine should be plentiful, but Thursday and Friday could have a few clouds thanks to a cold front that will be parking itself right over Tennessee. Warm southerly flow from the Gulf will also moisten up the air in preparation for our next (small) rain chance on Saturday. The video below is my last Mississippi State University Campus Connect weather update for the semester since classes ended today. Look for these to return next fall!

3/14 - 11:55pm EDT - Record-Breaking Warmth

The warm weather we've been seeing across the region hit record-breaking levels this afternoon. Here is a list of some broken temperature records today:

Jackson, TN: High 84° | Previous Record 80°

Memphis, TN: High 82° | Previous Record 80°

Chattanooga, TN: High 83° | Previous Record 81°

Louisville, KY: High 82° | Previous Record 80°

Paducah, KY: High 82° | Previous Record 78°
Evansville, IN: High 82° | Previous Record 77°

Indianapolis, IN: High 81° | Previous Record 79°

Many other cities in came close to breaking records, especially in Alabama and Middle Tennessee. The ridge over the Eastern US that's funneling all the remarkably unseasonable temperatures into the area will stay put through the weekend, but a few shortwave disturbances aloft will bring storm chances to much of West Tennessee, North Mississippi, and even into Central Kentucky tomorrow and Friday. These storms will be more organized than the spotty ones that developed in eastern portions of West Tennessee and even up through Western Kentucky this afternoon. The crazy-warm temperatures are going to last at least another full week as this strong ridge stays put, so I think to say that spring (or even summer) has sprung before winter officially ended!

8/4 - 11:30am - Finally, a Break in Sight!

Ridge breaking at 500mb on Wed.

The weather here in Louisville is about the same as when I left it last week on vacation in California! The good thing is that a cold front that came through yesterday will keep temperatures in the lower 90's today, as opposed to mid 90's for the last few days, and the humidity will be a little less oppressive. That said, daily afternoon storm chances will increase tomorrow and especially Saturday when an area of surface low pressure will pass right over us. That low and the accompanying cold front will finally begin the breakdown of this hot, humid ridge that we've been stuck under for so long, but not before some higher heat and humidity sneaks its way into the region for the weekend. Temperatures will be in the 80's next week as this pattern breaks, which could be temporary at best if some of the long-range models are to be believed.

So far we've had 40 days with highs at 90 or above in Louisville, with 18 consecutive days at 90 or above on our current streak. At this point last year we were counting 46 days in the 90's so far, so it seems this summer is a fairly close repeat of last.

Talk of development in the tropics has come to a fever pitch lately as Tropical Storm Emily seems to be taking a path that will pass very close to the southeast coast of Florida. The forecast path has been flip flopping around a little bit over the last couple of days, but at least right now it appears that Florida will not see a landfall from this storm. Emily has sustained winds at 50 mph, which is still a ways from the 74 mph needed to be declared a hurricane. The National Hurricane Center's forecast includes Emily reaching hurricane status by Monday well off the coast of South Carolina.

7/23 - 1:15pm - Heat Continues, No End in Sight

The entrenched heat we've had over the eastern half of the nation has been making headlines for quite some time now and it appears that it will continue for a while more. The strong ridge of hot, stagnant air is staying firmly in place and most forecast models are keeping it over the same area for at least the next week or two. A big portion of the Plains, Midwest, and East Coast is covered in heat advisories and warnings, which you'll see shaded in orange and purple on left.

Around Louisville, temperatures are going to stay in the 90's for the foreseeable future. For some perspective, we're hotter right now than Jackson, MS, Birmingham, AL, Memphis, TN, Jackson, TN, and Nashville, TN. Cloud cover, surface winds bringing in cooler air, and easterly flow aloft is keeping these locations cooler than Louisville even though they're all to the south. This really highlights the Midwest and Plains as being the primary target for the heatwave since we have been and will continue to be feeding off of the entrenched hot air from those regions.

A few pop-up showers and storms are possible today in Louisville, but a bigger chance for storms comes tomorrow as a "cool" front approaches the area that will cross through on Monday. I think tomorrow afternoon and evening will be the best time period for storms, most likely lasting into the early part of Monday. Behind this "cool" front temperatures won't really drop much, but dew points will take a tumble.

Check out the dew point output from the GFS for early Wednesday on the left. Those dew points are a good 15 degrees lower than the average this week and that translates to markedly lower humidity. That won't last long though... higher dew points with the same old hot temperatures will be back before the weekend. Until then, remember that an Excessive Heat Warning continues for the Louisville area until Sunday night. Stay safe!

7/18 - 12pm - Heat, Storms on the Way this Week

Many areas across Louisville saw heavy rain yesterday as scattered storms slowly made their way through the area. A setup like that will likely happen this afternoon as well with storms again coming from the north. Any chance of severe storms will stay to our north as the ingredients for this will be in better supply. Look for a high just over 90 degrees this afternoon in the city and a degree or two lower in the suburbs.

Disturbance over IN at 700mb

Tomorrow will be a different story. A small upper-level disturbance will be swinging our direction around a high centered in the Midwest. This should spawn an MCS (Mesoscale Convective System - a big complex of storms) in the afternoon that will move our way from the northwest. The whole evolution of the MCS and exactly who it will affect most is still murky at this point, but it seems the parameters for severe weather will be in place and the SPC has issued a 15% Slight Risk for the region. Damaging winds from bowing segments and even a few spin-up tornadoes are possible with this MCS tomorrow, so be on the lookout for warnings as they're issued.

Let's not forget about the heat! The National Weather Service has issued an Excessive Heat Watch along and west of I-65 from Tuesday afternoon to Friday evening due to heat index values reaching up to 110 degrees. Actual forecast highs in Louisville will be in the mid to upper 90's throughout the week, so get ready for an extended heat wave. Humidity won't be as extreme as last week, but even so we'll be seeing dew points getting into the mid 70's near the latter part of the week. Uncomfortable humidity starts with a 60 degree dew point, so you can imagine that mid 70's are pretty bad!

7/16 - 11am - Heat Building Back In

Ridge over Central US on Wednesday

It's been cooler and quiet over the past couple of days in Louisville with temperatures around and just below 90. That's going to change fast though as a hot and dry upper-level ridge begins to build into the eastern half of the nation next week. Today and tomorrow don't look particularly bad with temperatures in the low 90's and a slight chance of some afternoon pop-up thunderstorms

Thursday Eve. temperatures (GFS)

By Monday we'll be talking temperatures in the mid 90's and not a chance of rain in sight. The warming temperatures aloft with this ridge will limit instability for thunderstorm development significantly. Surface features like fronts will also be very hard to come by once this thing moves over us, so there won't be a trigger for storms either. What this means is that while the heat is building in we won't have any relief via the normal summertime afternoon storms that form. The compounding of the heat and dry air over the course of next week could send our temperatures to the 100 degree mark for the first time this season. Humidity-wise next week won't be as bad as it was earlier this week with dew points exceeding 80 degrees, but dew points in the mid 70's, still very humid, are possible especially on Tuesday and Wednesday. Below is some raw data from the GFS MOS output, which is basically a combination of numerical and statistical weather models. This output usually runs a  degree or two on the warm side this time of year, but I've highlighted the warmest temperatures of the week in red and highest dew points in green:

GFSX MOS (MEX)
 KSDF   GFSX MOS GUIDANCE   7/16/2011  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|
 SAT  16| SUN 17| MON 18| TUE 19| WED 20| THU 21| FRI 22|
 X/N  89| 73  93| 75  95| 78  96| 79  98| 78  99| 78  97|
 TMP  85| 75  88| 77  90| 80  91| 81  92| 80  93| 80  91|
 DPT  69| 70  69| 72  70| 75  74| 75  72| 72  71| 71  70| 
 CLD  PC| PC  PC| CL  PC| PC  PC| PC  PC| PC  PC| PC  PC| 
 WND   6|  6   7|  6   9|  9   9|  9   8|  7   8|  7   8|
 P12  24| 13  14|  7   9| 19  40| 27  20| 12  25| 14  19|
 P24    |     19|      9|     40|     40|     25|     34|
 Q12   0|  0   0|  0   0|  0   1|  0   0|  0   0|  0    |
 Q24    |      0|      0|      1|      1|      0|       |
 T12  26|  8  32| 10  24| 37  49| 49  39| 29  28| 21  36|
 T24    | 30    | 40    | 50    | 71    | 49    | 44    |

Looks pretty hot doesn't it? A span of three or more 90 degree plus days is usually considered a heat wave, so I think we'll meet and exceed that definition easily. Next week will be a good time to take it easy and drink lots of fluids when working or playing outside. Here comes the heat!

7/12 - 10am - Another Day of Incredible Heat

Here we go again. It's already 87° with a dew point of 81° in Louisville and we're just getting started. See that condensation on my door to the left? That started at 10pm last night when the temperature dropped a couple degrees and just now cleared up with sunlight and a bit of heating. That's some crazy humidity right there. I think we'll get near yesterday's high of 97 again today, but like yesterday the dew point is the bigger story. With such a high temperature and high dew point in the low 80's (which is almost unheard of in Louisville), heat index values will be exceeding 110° again. An Excessive Heat Warning has been issued that goes from 11am this morning to 8pm this evening.

...But wait! There's more. We're under a Slight Risk from the Storm Prediction Center for severe weather this afternoon as a cold front approaches the area from the north. This is mainly a wind threat (notice the 30% wind risk red area on the right), but there's also a small chance for hail. A lack of wind shear and helicity (turning of the atmosphere) will eliminate any tornado threat for the most part. This front should be the trigger for some southward-moving clusters of scattered storms this afternoon. With all the heat energy and moisture in the area, there's no question that some of these could reach severe limits as the SPC indicates. Not everyone will see storms this afternoon, but those who do will receive quite a bit of rainfall, lightning, damaging wind, and a break from the heat. The cold front is positioned just south of Indianapolis right now and is moving fairly slow, so there will be quite a bit of time for storms to fire today and tonight before the front passes through sometime early tomorrow.

7/11 - 6:45pm - It's So Hot You Can (sorta) Fry an Egg!

It's 96° outside in Louisville with a heat index of 114°, making this the hottest day of the year so far. This got me thinking: Is it hot enough to fry an egg outside? I grabbed an infrared thermometer (measures temperature without having to make contact with the surface) and did some tests to see how hot various surfaces around my house were. The wooden deck was 149.3°, the tan concrete of our patio was 130.6°, and our driveway was 129.5°. While all very hot surfaces with direct sunlight, the deck was a clear winner.

Now to the egg frying part. I didn't want to fry an egg on the surface of the wooden deck because it may stain it. So, I put a metal cookie sheet right on top of the deck surface. This not only protects the deck, but easily heats up in the direct sunlight. After a few minutes in the sun, the temperature of the cookie sheet with non-stick spray applied about equaled the temperature of the deck surface.

Since the refrigerator at my house was void of eggs, I poured out the one-egg equivalent of egg beaters, the made-from-eggs substitute that you find at the grocery store, into a measuring cup. This may have thrown my results a bit, but hey, this is supposed to be fun right? Once the cup of egg beaters warmed to the ambient air temperature (around 96°), I poured it out on to the cookie sheet.

The results were interesting. I spread the liquid eggs around on the pan to resemble a flat pancake or crepe to increase surface area for heating. After a few minutes the edges of this "pancake" turned crispy and the middle became a thicker liquid with solid "chunks" (yeah, don't read this if you're getting ready to eat dinner) embedded in it. The surface of the deck was cooling down just before five o'clock, so this marked the end of the experiment. Had the temperature outside been a little hotter, and hence the deck a little warmer, it could have cooked more thoroughly. The temperature of a safely cooked egg is about 160°. Check out the video below to see the end result:

Today felt so hot because the dew point was near or at 80° for a good portion of the afternoon. That's a rare occurrence and signals the presence of an intense amount of moisture in the air. Humid is an adjective that doesn't even describe how it felt. Tomorrow should be almost as hot with the high topping out near 93 and heat indices near 110. This has prompted the National Weather Service to issue another Heat Advisory from 1pm to 8pm tomorrow. A "cold" front accompanied by a little southward dip in the jet stream (a trough) will increase scattered thunderstorm chances tomorrow afternoon in Louisville. The Storm Prediction Center places us under a Slight Risk for severe weather, mainly due to the threat for some hail and strong winds. The chance for storms could continue into Wednesday morning as the front passes through, but the lack of surface heating should suppress most of the development. We should dry out for the rest of the week with highs near 90. Stay cool out there!

7/10 - 3:30pm - Heat Advisories and Warnings

The hottest days of summer are yet to come, with today and tomorrow being just the start. A ridge of high pressure has locked itself into the eastern half of the nation, and many are feeling its hot and humid effects. It's 91° at Louisville International Airport, 88° in the southeastern suburbs of Louisville, 91° in Bowling Green, KY,  and 95° in Jackson, TN as of 3pm EDT/2pm CDT. Doesn't take me to tell you that those are some hot readings! Areas near the Louisville area have been placed under a Heat Advisory until 8pm tomorrow while areas to the west of Owensboro have been placed under a more strongly-worded Excessive Heat Warning. Highs in Louisville could reach near 96° tomorrow with heat indices ("feels like" temperatures) up to 110.

Most of West Tennessee is under an Excessive Heat Warning until tomorrow at 10pm. Jackson could get up to 100 tomorrow with Memphis easily passing into the triple digits. Heat indices near or above 110 are expected, so limit your time outside if possible and drink lots of water.

As a trough and associated "cool" front dip down from the north, we should see chances for storms enter the forecast by Tuesday, which will help to break the heat a bit. While more scattered in Tennessee, Kentucky will likely see a good helping of storms during Tuesday afternoon and evening, some of which may be strong. The Storm Prediction Center has placed portions of Kentucky (including the Louisville area) under a Slight Risk for severe storms. I don't think there will be much, if any, of a tornado and hail threat from these, but gusty winds could present some issues across the region.

7/8 - 3:30pm - Here Comes the Sun!

It's been a rainy one around Louisville today. The airport has had .45", my house in Southeast Louisville received .88", and Shelbyville got .72" of rain since midnight. Bullitt, Hardin, and Meade Counties in Kentucky all received well over an inch of rain, but Frankfort is the winner coming in at 2.13" since midnight. Check out some of the rain amounts since midnight in the map below from the Kentucky Mesonet. The clouds are still hanging around just east of Louisville, but Louisville and westward is seeing some sunshine. That trend should continue eastward as the afternoon goes on. There's a chance that some scattered storms could redevelop later today around the area, so a few locations could receive more rain today before the cold front triggering these storms moves south.

Sunshine and warmer temperatures will be the rule this weekend around Kentuckiana. High pressure will keep the clouds out of the picture through Monday and temperatures above 90 degrees are a sure bet until then as well. Monday will likely be the hottest day (low to mid 90's) in the near future before another front approaches the area and increases afternoon storm chances yet again.