WKU Meteorology

Town gossip has seen a rise in the use of the s-word recently. And that word is snow! Yes, last week there was a chance of snow placed in the forecast for tonight, but that hype has died out as the models are showing temps in the 40s and upper 30s as the precipitation rolls through our area today into tonight. That means it will be all rain this time around, but watch for a different story come mid-week.

We started off today in the mid 40s with a light drizzle, and it will remain cold with on and off drizzle throughout the rest of the evening through tomorrow morning. Tuesday will remain in the 30s all day as 10 mph winds from the North bring in cold air all day long. Overcast conditions will also prevent near-surface air temps from warming. Expect your high temp of 41 to occur during the middle of the night. Temperatures will steadily drop through the 30s during the day and into the upper 20s overnight Tuesday into Wednesday.

18Z NAM showing statewide mid-afternoon temps in the low to mid 30s Tuesday – Courtesy of Pivotal Weather

Wednesday morning will start cold in the upper 20s and feel even colder with winds again coming out of the North around 10mph. Temperatures will edge into the low 40s by midday.

18Z NAM showing temps in the 20s all across KY at 6am CST- Courtesy of Pivotal Weather

Thursday will start and end wet. Rain will begin very early Thursday morning and continue throughout the entirety of the day. As the sun sets, the predicted track of the upper level low will take it across South Central KY and advect cold air into the region. This will turn the rain into a wintry mix and eventually all snow later in the evening. It’s too early to determine any accumulation amounts, so make sure to tune in over the next couple days for more updates.

18Z GFS showing rain changing to snow by the evening hours on Thursday – Courtesy of Pivotal Weather

Tuesday: High of 41 around midnight with rain ending before noon. Daytime temps will be in the 30s with dry conditions.

Wednesday: High of 41, low of 28. Partly cloudy skies and dry.

Thursday: Rain becoming a wintry mix by the evening hours. Temps staying in the 30s all day, possibly nosing into the low 40s.

Overall, make sure to dress warm and be extra vigilant while driving this week. Driving in the rain is bad enough, but with the added threat of a wintry mix, it will be imperative that you drive slow and apply the brakes a second earlier than usual when approaching a red light or stop sign. If your tires are balding, try to get new ones either tomorrow or Wednesday before conditions deteriorate Thursday.

Currently there is a high pressure system passing over Kentucky. A system centered in Wisconsin will pass eastward bringing with it some snow. Most of that snow will be to the north. A high pressure system will come down from Canada on Monday trying to bring colder temperatures with it. A low system in the west right now will be settle around the Carolinas at that time and will prevent temperatures getting too low. This will help keep most precipitation as rain.

Not much will occur for today as the high pressure system move us moves east and settles over the mid-Atlantic. Clouds over the midwest will be pushed into the area leading to mostly cloudy skies for the afternoon.

The southern part of the trough passing through Tuesday will become cut off. Where we sit will allow the cutoff to clear the skies.

SUMMARY:

• Sunday:
  • High: 51
  • Low: 21
  • Conditions will become cloudy this evening.
• Monday:
  • High: 47
  • Low: 36
  • Precipitation: Around a quarter to a half an inch with the majority of it being rain.
• Tuesday:
  • High: 40
  • Low: 33
  • Conditions will improve beginning Tuesday night.

Last night’s cold front has brought in a wave of much colder air, giving us the cold air typical of a winter season. A strong high pressure field will bring in sunny skies to bring sunny conditions for your Saturday.

So dust off your winter jackets, mittens, and toboggans as high temperatures will only reach the mid-upper 30’s and lows will sink below freezing into the mid-20’s. Our Sunday will be slightly warmer with highs into the mid 40’s, and lows into the mid 30’s, with increasingly cloudy conditions, which will transition into complete overcast as of Monday. In fact, Monday may seem some rain for the afternoon hours, and perhaps snow will enter the picture for the evening hours. Expect highs into the mid-40’s and lows into the mid-30’s, so don’t expect the snow to stick.

6Z NAM Precipitation Type (Source: College of DuPage)

Forecast:

Saturday: Clear and cold: High: 37, Low: 26

Sunday: Increasing clouds for the afternoon, High: 44, Low: 36

Monday: Afternoon rain, evening flurries, High: 46, Low: 35

Greetings!

A window into the winter months looks to be coming into our area today into the weekend. Friday starts off as a wet day with  a high in the upper 40s. By 8 AM, the rain is starting to move out of the area. As the rain chance diminishes in the afternoon hours, the clouds stick around all day Friday in clears out Saturday morning.  We can not fully say the rain chance is zero percent with the still some forcing is still lingering around the majority of the day.

Looking at the thermal profiles, it is possible to see a mix precipitation night with the Cold Air Advection (CAA) moving into the area. According to 06z GFs, around  21z, 3 central time, a strong CAA will start to come into the area and become stronger as the day evening and night goes on.

The mixture will not affect traveling with the pavement temperature in the upper 40s the precipitation that makes it to the ground will melt on contact.

Saturday will be cloud at the start of the day, but will clear out before the afternoon hours. As  low level high moves into the area it will bring clear weather here. The temperatures will start in the 20s then rise to the 40s by the afternoon. If you go out tomorrow you better bring your winter jackets and stay warm!

As the ridge axis comes into the area later part of the weekend it’ll allow for a little warm up Sunday with highs in the upper 40s, however Sunday morning will be in the 20s again. By afternoon Sunday there will be an increase in mid-level moisture which will cause an increase in clouds.  The beginning of next will will start of rainy with a cold week ahead!

Summary

Friday: 47/26 slight chance of rain into the night

Saturday: 41/24 clear with wind

Sunday: 49/36 Increase in clouds by afternoon

Good afternoon folks!!

Cloudy skies from this morning have transitioned into partly sunny skies this afternoon. Thanks to the cloud cover from this morning and a steady wind out of the NE, high temperatures for today should top out in the middle 50s across much of the area.

The rain chances are on the increase as we head into tonight, thanks to an elongated middle to upper-level trough moving through the region with a strengthening jet stream over the Ohio Valley. The strengthening of upper-level winds indicates divergence aloft and convergence in the lower-levels of the atmosphere. The peak strengthening of the shortwave will likely happen over eastern KY as the SW low-level jet kicks it into gear during the overnight hours. PWAT (Precipitable Water) values are suppose to reach about an inch just east of Bowling Green area. Precipitable Water is the measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location, usually extending from the surface to 300 mb (NWS Glossary, 2009). The response or result will be numerous rain showers throughout south central Kentucky.

Below: NAM 09Z 11-09-2018 PWAT & Sfc-400mb Mean Wind

For your Friday, rain chances stick around for the morning hours as the upper-level trough axis and surface low pressure move northeastward. Light rain showers will exit the region heading into the early afternoon hours with partly cloudy skies sticking around for the rest of the day. High temperatures across the area on Friday will have a hard time getting out of the 40s thanks to the persistent cloud cover and a steady wind out of the NW. The figure below shows CAA (Cold Air Advection) filtering into the area from the north throughout the day on Friday.

Below: NAM 18Z 9-9-18 850mb Theta-e & Winds

Friday night, high pressure will build into the area from the west. Cloudy skies from earlier in the day will move out of the area during the early evening hours, giving way to mostly clear skies. Temperatures throughout the evening hours and into the early morning hours will cool quite a bit thanks to the mostly clear skies. Temperature cools off more under clear skies, because heat that is emitted from the earth’s surface escapes freely into the atmosphere resulting in cooler temperatures. Low temperatures across the area for Friday night will struggle getting out of the 20s.

Surface high pressure that moved into the area from the west will dominate the region the whole weekend. High pressure over the area means that conditions will remain dry and cool. High temperature for the Bowling Green area will climb into the upper 30s, possibly hitting 40°.

Forecast

Tonight: Rain with otherwise cloudy skies. Low around 42° with NE winds at 5-10 mph. Precipitation totals less than a quarter inch.

Friday: Showers mainly in the morning hours. High temperature of 48° with NW wind at 5-10 mph. Precipitation totals during the morning hours of less than a quarter inch.

Friday night: Partly cloudy skies with a low of 28°. NW winds at 5-10 mph.

Saturday: Sunny skies, High of 40°. NW winds at 3-8 mph.

Over the next week and a half, much of the U.S. (including us!) will experience multiple shots of cold air.  The models have been remarkably consistent with the cooler pattern taking over, at least for now.  The first cold shot will be Friday night into Saturday morning-  you can expect upper 20s for our region with chilly winds around 12 mph.  Bring all your plants and pets indoors!  The run of the NAM shown below really helps to illustrate how deep this cold will get:

With each shot of cold air, there is some slight potential for- you heard right- snowflakes!  For the period of Friday into Saturday, some of the short range models have started showing the possibility for a few stray snow showers in the region.  This will be something to keep an eye on over the coming days, however the better chance at seeing flakes actually comes with the second blast of cold air Monday into Tuesday:

Above is the GFS for that second blast of cold air.  Temperatures could fall into the 20s again, and have yet another chance at seeing a few flakes.  It’s still pretty far out from now, so we’ll have to watch how this unfolds over the coming days!

There is a third blast of cold air after next week on the horizon- or at least the signal for it is there.  No doubt you’ll be needing your heavy coats at times over at least the next few weeks.

Tonight: Low of 36, Partly Cloudy

Tomorrow: High of 54, Low of 40 , Scattered Showers

Friday: High 47, Low 29, Rainy and Cold- chance of a snowflake late

Good afternoon WKU!

It’s Tuesday and Happy Election Day young citizens! This is a great day to get out and cast your vote for the upcoming state elections. Voting is very important as a democratic nation, and since the rain has ceased revealing perfect fall weather, there won’t be any excuse to defy the odds before polls close at 6pm. But first, a quick weather recap of Monday’s rain accumulation.

Monday’s rain totals were just several notches away from two inches in Bowling Green, Ky.! The final observation was calculated to be 1.79″ of rainfall (courtesy of NWS Climatological Report).

Tuesday will be less of a rain threat due to the moisture being wrung out of the area from a cold frontal passage. Skies began to open up this morning unveiling partly cloudy skies with a glimpse of sun. Maximum temperature for today will be 65°F but conditions start to get drastically colder after this evening.

A second cold sector sweeps through the Mid-South area associated with a fast moving cold front. Considerably, maximum temperatures for Wednesday and Thursday will be in the middle tier of 50°F. Rain chances will be prevalent for Wednesday morning before 7am but will soon clear out for a chilly and breezy day.

Overall, Tuesday is Election Day! This year’s votes involve congressional, Kentucky House and Senate, mayoral, city council and judicial races, and a constitutional amendment, among others. Temperatures are suitable enough to get out there and make your voice heard.

GO VOTE!

Tuesday: Partly sunny with a slight westerly wind, drier conditions due to passage of cold frontal boundary. 65°F/48°F

Tuesday PM: Mostly clear with a calming wind of about 3 mph. Overnight low of 49°F.

Wednesday: Mostly cloudy; Morning scattered rain chances of 30% then deteriorate to a drier atmosphere and windier conditions.  53°F/39°F

As Kelli mentioned yesterday, a line of strong to severe storms will push through South Central KY this evening and into the overnight hours. Previously, the Storm Prediction Center placed Bowling Green in an enhanced risk for severe storms, but BG has been downgraded to a slight risk as of this morning. However, that does not mean you can let down your guard! Let’s walk through the components for severe weather and which of these conditions we expect to have today and tonight.

For strong storms to develop, one should look for 3 big things: moisture, lift, and instability. A fourth ingredient – wind shear (speed and directional) – provides additional support for the development of severe storms, specifically supercells and possibly tornadoes.

12Z NAM showing DPs increasing throughout the afternoon and evening to values in the low to mid 60s. – Courtesy Pivotal Weather

Ahead of the storms, we’ll see moisture and warm air advect from the southwest. The dew point temperature and air temperature in Bowling Green right now (1pm data) are 53 and 64 respectively. A warm front will be pushing into our area during the early evening hours and increase our those values into the low 60’s and upper 60’s respectively. One thing reducing the potential for additional lift attributed to warm air temps is cloud cover. Because of the decent cloud cover we have experienced throughout the morning to noontime hours and the additional cloud cover we will have during the peak heating hours, this will keep our temperatures cooler and reduce (but not eliminate) at least one ingredient for severe weather. Currently, we’re experiencing a clearing trend, so the sun is having its first opportunity to add more significant energy to the lowest levels of the atmosphere.

12Z NAM showing MUCAPE values around 500 J/kg just ahead of the arrival of the QLCS. – Courtesy of Pivotal Weather

The amount of instability typically required for severe storms can vary greatly depending on what time of year the storms occur. Summer time storms require massive amounts of CAPE (convective available potential energy), but storms during the Fall don’t need values nearly as high. Expected CAPE for this event will be around 500 J/kg, which is enough to fire up some storms; however, if storms develop ahead of the Quasi-Linear Convective System (QLCS) that we’re expecting, they will consume some of the required CAPE to create a severe environment for the main line of storms.

12Z NAM depiction of rain (first frame at 3pm, last frame at 3am). – Courtest of Pivotal Weather

One final thing to consider is the amount of rain that will fall during this relatively short period of time. Models are pointing to a widespread area of an inch of rain, but many places could receive upwards of 2+ inches if they experience storms ahead of the QLCS. Be extra careful if you are out and about during the late night/extremely early morning hours. Turn around, don’t drown.

With all of this in mind, there will be sufficient moisture and decent CAPE (instability) and decent lift to create severe weather, but lift and CAPE will be reduced if cloud cover over our area remains throughout the day and if storms fire off ahead of the QLCS. Therefore, make sure to tune in to your favorite weather source tonight, whether that’s TV, radio, or social media. Also, stay safe by having a plan for your entire family. This includes everyone knowing where to take cover (an inner room on the lowest floor of whatever building you’re in with no windows) and having a weather radio on hand.

Weather concerns: mainly winds greater than 60 mph, slight chance for a tornado, flash flooding possible, no significant large hail threat for our area.

For updates during the event, you can follow any of these WKU Storm Team social media accounts:

Facebook: WKU Storm Team

Twitter: @wkustormteam

Instagram: @wkustormteam

Last Thursday Louisville’s Meteorologist in Charge, John Gordon, asked Twitter to give the names of some famous rain songs. Of course, two that had to be mentioned were “November Rain” by Guns n’ Roses and “Kentucky Rain” by Elvis Presley. The start of this week will be the perfect time for both songs. A cold front out to the west with a low pressure system centered in Iowa is making its way towards the area this evening. With it will come cooler temperature along as well as rain.

GFS is showing some low end bulk shear coming through the area starting Monday night going into Tuesday. This along with winds gusts and increased vorticity shows for the potential for severe weather stating tomorrow night. Right now it looks like everyone should keep an extra eye out starting around 6 pm tomorrow.

GFS vertical vorticity

Models are showing rain fall totals between 1 and 2 inches. I believe there will be areas that see 2 or more inches. Winds will have the possibility of knocking limbs out of branches and could cause some to lose electricity if gusts reach high enough.

SUMMARY:

• Sunday:
  • High: 61
  • Low: 47
  • Some precipitation
• Monday:
  • High: 69
  • Low: 55
  • Rain along with strong winds.
  • NOTE: There is the potential for severe weather staring tomorrow evening. There will be strong winds with gusts up to 65 mph, potential for flooding as well as isolated tornadoes.
• Tuesday:
  • High: 65
  • Low: 45
  • Chance of precipitation.

As always: please be safe and have a good week!

A ridge has allowed for Bowling Green citizens to enjoy sunny skies for our Saturday. It won’t be so warm today with highs only in the mid-50’s, and lows getting down to the low 40’s. However, as we conclude our weekend, we will experience a radical change in weather conditions. The conclusion of this weekend also spells the end of daylight savings time. Remember to set your clocks back one hour and enjoy your extra hour of sleep.

Sunday is facing a chance of rain as the afternoon progresses; nevertheless, there will be warmer temperatures, with highs into the upper 50’s and lows in the mid to upper 40’s.

Monday will face a greater chance for rain into the evening and overnight, with otherwise little activity for the morning. Highs will be in the low 60’s and lows will be in the low 50’s as Monday will face more warming towards the evening.

Summary:

Saturday: Sunny skies, High: 59, Low: 41

Sunday: 50% chance for rain in the afternoon, High: 60, Low: 48

Monday: 80% chance for rain in the evening hours, High: 60, Low: 50