WKU Meteorology

I hope everyone enjoyed the sun today, because that all is going to change this week.  There is a system out to our west right now that is going to move to the east causing us to see some rain, sleet, and snow this week.

Right now, we are under high pressure.  That will move out of the way for a low pressure system to make its way in.  Also, a cold air mass will make its way down causing our temperatures to make a 15 degree drop by Wednesday.

 While the low pressure system comes in, it will bring with it some rain ahead of the front, and as the front passes we will see some rain/snow mix.  This could cause some iffy conditions as we head through the end of the week.

If you look at the top right, there is a low pressure system moving east and the 540 line, which is the indicator of snow, still has us under rain, but as the low moves off then we will likely see some rain/snow mix.  Some accumulations are possible.

Monday: Sunny skies will continue through the morning, but as we head through the afternoon we will see increasing clouds.  Highs in the mid 50s.

Monday Evening: Showers will likely return and temperatures will be in the low 40s.

Tuesday: Rain is likely with temperatures in the upper 40s.

Tuesday Evening: Rain will start to mix with snow and this could cause icy conditions through the night and into Wednesday morning.

Days at a glance:

Thursday: High – 46  Low – 21  Precipitation – 30% chance early rain showers with the impending warm front, totals will be less than .25 inch  Winds – N switching to E early 12-16mph  Sky – mostly cloudy with clouds increasing into the evening

Friday: High – 62  Low – 41  Precipitation – 100% chance rain showers associated with the warm front early and mid-morning  Winds – S 13-17 mph switching to NW 6-9 mph late evening  Sky – Overcast throughout the day, with clouds beginning to thin late evening

Saturday: High – 46  Low – 31  Precipitation – 0% chance  Winds – W 5-8 mph  Sky – mostly sunny

Sunday: High – 51  Low – 27  Precipitation – 0% chance  Winds – SE 5-8 mph  Sky – sunny

Discussion:

Today was a beautiful, but chilly day with blue skies and a high of 35. Bowling Green is currently at 26 degrees, with clouds rolling in from the west. With clouds, the low tonight will stay above 20. Tomorrow will be a slightly warmer, but cloudier day with a high in the middle 40’s. Winds will be out of the east, switching to southerly around midnight. This is preceding the disturbance mentioned in the previous discussion and will keep the low above 40. Throughout tomorrow night into Friday morning, clouds will increase with showers also increasing into Friday. This is due to a warm front with precipitation ending into Friday afternoon. Expect precipitation to be light to moderate in intensity and persistent in the early and mid-morning hours before tapering off.  Precipitation will be in the form of rain since temperatures will be in the low 40’s and rising as the front passes with totals less than one quarter of an inch.

Forecast surface analysis for Friday morning at 6 am CST. Notice the showers over our area associated with the warm front to our south

Later in the day around 5 or 6 pm, the cold front will pass with little precipitation expected. With that said, clouds will persist throughout the day. After the cold front passes, winds will shift from the northwest as cold air filters into our area into Saturday. Saturday and Sunday will be nice, but on the chilly side. Enjoy the fantastic weather this weekend!

Today was a beautiful day with a high of 44 and blue skies.  Tonight’s low will slip into the upper 20’s under mostly clear skies. A brief warming trend will begin tomorrow throughout the day with southerly winds predominating. High’s will get into the upper 50’s and maybe 60. This is preceding a cold frontal passage late tomorrow evening around 10 pm. Available moisture and instability will both be minimal, giving low confidence for organized precipitation. Regarding precipitation type, models are keeping surface and near-surface temperatures above freezing during the time of expected precipitation, giving high confidence for rain. With intensity, the surface low will  be to the north near the Great Lakes. This increasing distance may lessen the strength of the front as it passes our area.

Considering amount, models are calling for upwards of three quarters of an inch. The earlier stated weakening front, minimal moisture, and lack of instability lower my expectations to under half an inch. Given it is a cold front, any precipitation that falls will be relatively brief, but intense. It should be hit or miss. Half an inch will be my upper threshold. After the passage, temperatures will drop and remain on the chilly side for Tuesday and Wednesday. Another brief warming trend will commence Thursday ahead of a more promising disturbance Friday. There will be mid-week details regarding this feature.

Days at a glance:

Monday: High – 59  Low – 27  Precipitation – 80% (.35 inches rain)  Wind – S increasing throughout the day up to 20-24 mph then switching late to NW 13-15 mph  Sky – clear with clouds gathering into the evening

Tuesday: High – 43  Low – 31  Precipitation – 10% residual rain from cold front  Wind – NW 11-13 mph  Sky – cloudy skies becoming clear by afternoon

Wednesday: High 39  Low – 21  Precipitation – 0%  Wind – NW 5 mph switching to N and E late  Sky – clear

After a very nice Thursday with sunny skies and a high near 60 a cold front will be bringing a change in temperatures to the state.  Currently a trough is centered over the central US with a few disturbances riding through.  Furthermore there is a surface low pressure over the Great Lakes and the aforementioned cold front extending to the south moving into Kentucky.  With these small disturbances and the trough moving into Kentucky much colder air will spill in from the northwest which will set up a chilly weekend.

Surface map indicating the Low Pressure near the Great Lakes and the cold front bringing in cold air (blue arrows) into KY for this weekend.

Temperatures especially on Saturday will be as much 10 degrees cooler than average.  These disturbances moving through will bring increased cloudiness  and there will be a chance for an occasional sprinkle/shower or flurry especially on Friday.  By Sunday afternoon these disturbances will move off to our east as a ridge of high pressure moves toward the Ohio Valley/Mid-south region.  This will provide for a brief warming trend by Sunday with some clearing especially Sunday afternoon.  The next big weather maker for area looks to be sometime in the Monday-Tuesday time frame when showers and possibly a few storms will move through.

Daily Forecasts:

Friday: Morning low near 35.  Cloudy with a 30% chance of a shower, a few flakes could mix in.  Chilly with a high near 44.  Northwest winds from 5-10 mph.

Friday Night: Mostly cloudy with occasional clearing.  Cold with a low around 25; light NNW winds.

Saturday: Chilly and mostly cloudy; high near 36.  Northwest winds from 8-14 mph.

Saturday Night: Partly to mostly clear and cold with a low near 21.  5-10 mph winds switching to the WSW.

Sunday: Partly cloudy with a high near 46. South to southwest winds from 6-12 mph.

Monday: Morning low near 32; daytime high near 58.  Partly cloudy becoming cloudy with a chance of rain and possibly thunderstorms by the afternoon.

Sunday’s rainfall has moved out of south-central Kentucky after the area received anywhere from 0.25 – 0.50 inches of rain.  This rainfall was due to an approaching storm system with a cold front which will not actually make it’s way through the Commonwealth until overnight tonight.  Until the passage of the front the chance lingers for a few showers and sprinkles; any lingering precipitation will be light.  By Monday the rainfall and clouds of Sunday will just be a memory as a surface high pressure will begin to work it’s way in.  The strong low pressure centered over the upper-Great Lakes however will be close enough to make it another windy day (though not as windy as Sunday) with winds from the west from 10-20 mph with gust 20 mph +. Other than the wind it will be a mostly sunny day with highs in the upper 50s to near 60.  Tuesday should be another nice day though slightly cooler thanks to more north-northwesterly winds from the lower levels of the atmosphere to the surface.  Clouds will also be moving in during the afternoon ahead of the next storm system.

An upper-level disturbance will eject from the four-corners region Tuesday and move toward our area.  Furthermore a surface low pressure system will try to develop in Texas and then move to the east and north.  This in turn brings a good chance of showers from Tuesday night through Wednesday.  The sub-tropical jet will bring ample Pacific moisture to the area but the track of the low should be to our south and thus the heaviest precipitation should also pass to our south.  Nonetheless it appears that rain is likely with anywhere from a 0.1 to 0.30 inches of rain mainly during the day on Wednesday.  There is a chance given the strength of the upper-low and the cold pocket of air aloft that will move over our area associated with the system that some wet snow flakes could mix in at times with the rainfall especially Wednesday afternoon. Notice on the image below that the blue 0 degree line at 850 mb is south of most of Kentucky which would normally indicate snow.  However such warm air at the surface will likely keep most of the precipitation as rain.  Nontheless a full transition to wet snow Wednesday afternoon cannot be ruled out however nothing of any significance and no

GFS precipitation and 850 temperatures for noon Wednesday.

accumulation is expected at this time.  Behind this system the weather will turn dry for a while with colder air moving in.  Indications show that from Friday and especially into the weekend much colder air will return to Kentucky.

Climate Prediction Center’s 6-10 day temperature outlook indicates a good chance of below average temperatures.

Daily Forecast:

Tonight: Cloudy skies with a chance for a few sprinkles or even an isolated shower.  Low near 44. 8-14 mph winds from the south switching to the west around midnight.

Monday: Mostly sunny with a high near 58. West winds from 10-20 mph with gusts 20 mph +.

Monday Night: Clear skies with a low near 30. Light WNW winds.

Tuesday: Mostly sunny to start but cloudy by the afternoon; high near 51. Light north to northwest winds.

Tuesday Night: 50% chance of showers with a low near 34.  North to northeasterly winds from 3-8 mph.

Wednesday: 60% chance of showers possibly mixed with wet snow during the afternoon. No accumulation expected. High near 42. Rainfall totals between 0.1-0.3 inches.

Thursday: Morning low near 33; Mostly sunny skies with a high near 58.

After a busy weather weekend, conditions have begin to calm down just a bit with clear and milder temperatures across the state.  High pressure will continue to shift over our region towards the east near Pennsylvania/New York by this evening.  Highs for your Wednesday are expected to reach the upper 40’s, low 50’s with mostly sunny skies.  Winds will be light and variable through much of the day before shifting to  a more southerly wind by Thursday. These southerly winds will be ahead of an advancing trough from the Central Plains as our region looks to be between two systems associated with this trough.  The models continue to show our best chance at some light precipitation with the northern system as we head into Thursday evening and early Friday morning.  Models continue to indicate weak isentropic lift in between the two systems by Thursday evening, leaving the area a chance to see some isolated – scattered showers move through.

GFS 500mb Heights & Vorticity valid for Friday 12Z.

GFS MSLP, PCPN (In.) and 1000-500mb Thickness valid for Friday 12Z.

The latest GFS run for 500mb Heights and Vorticity map shows the northern disturbance over the Great Lakes with a progression towards the northeast.  As far as concerns for precipitation, a light rain event will primarily dominate this event as the GFS precipitation and thickness map hints towards this possibility with 0.01 – 0.10 inches of rain accumulation.  Conditions for your Thursday look to stay dry through the morning hours under partly sunny skies.  Temperatures look to warm up nicely by the afternoon hours with a high around 58º.  Heading into the evening and overnight hours, we’ll see the best chance for showers with a low around 42º under mostly cloudy skies.  Expect the heaviest rains to occur through the evening and overnight hours as we’ll see another high pressure build back into the region by Friday.   Clearing skies accompanied by cooler conditions will be the main talk of the day.  Low to mid 40’s will be expected state wide with light winds from the northwest.

Last week’s wild weather continued into the weekend as continuous Alberta Clipper systems swept through the Ohio Valley Region. Parts of Central and Eastern Kentucky received the first dose of measurable snowfall with a couple clipper systems dropping 2-4 inches of snow for those areas. South-central and western parts of the state missed out on most of the action by picking up a dusting of snow, with far western counties receiving no accumulations. Another clipper system developed over the mid-west and quickly moved through parts of Missouri late last night. Quick burst of snow was recorded over parts of St. Louis as accumulations ranged from 2-3 inches of snowfall. The HRRR last night showed positive signs for snow lovers across south-central KY as 1 hour accumulated snowfall rates of 1-2 inches/hr were possible along the I-65 corridor and westward.

Snowfall was forecast to impact the Bowling Green area this morning and did so by dropping an official inch of snow.  This intense and quick hitting system affected areas just to our north and west as the hardest hit areas along a narrow axis extending from Ohio County through Edmonson, Barren and southern Hart counties picked up 2-3 inches of snow.  As far as Bowling Green is concerned, some photos were taken this morning as the heaviest snow began to fall around 3am.

Photo captured early this morning on campus. Heavy snow covered many roads and side streets along the area making for cautious travel around town. (Credit Photo to STN)

Another photo capturing the heart of Campus with a light blanket of snow covering the ground. (Credit Photo to STN)

Snow abruptly came to an end shortly after its impact over Bowling Green as the system continued to work its way through eastern Kentucky and Tennessee by late morning.  Cloudy skies are expected to stick around through the afternoon hours before some partial clearing to our west occurs.  Temperatures in the forecast look to warm up as highs make a run towards 40 degrees in Bowling Green.  Clouds should continue to push to our east as Mostly Sunny conditions should prevail by mid-afternoon with wind from the west around 10-15 mph.  Expect partly cloudy conditions tonight, with a cold low around 24 degrees.

Looking ahead for your Monday, another system is expected to impact the area by Monday evening and could bring a rain/snow mix to the area.  The latest model run (NAM) shows another system with a bit warmer air mass and more moisture to sweep through as precipitation is likely to start out as rain before switching to snow late Monday night/early Tuesday morning.  Light snow accumulations are expected at best with better chances of snow to our north.

NAM valid for Tuesday 3Z… MSLP, Thickness (1000-500mb), and Precipitation.

Latest NAM model run shows the 5400 line cutting the state nearly in half as this gives a good idea where the rain/snow line could exist.  As mentioned before, areas to our north will see a better chance at a light accumulation with more of a rain/snow mix towards the south and west.  Monday’s temperature will continue the warming trend with highs around 47 degrees with a slight chance of rain through the late afternoon hours.  Lows for your Monday night will hover right around the freezing mark as the chance for rain/snow mix will exist.

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Tuesday: Partly sunny conditions. High: 45º. Southwest wind around 5-10 mph.

Tuesday night: Mostly Clear skies. Low:29º. Light and variable winds.

Wednesday: Mostly Sunny. High:48º

We saw about every season this week.  From tornadoes to snow.  It has been a crazy, intense week here in South Central Kentucky.  We first saw fall like temperatures earlier on in the week and then we transferred right to summer like temperatures with 70 degree temperatures Wednesday Morning.  Yes, that’s right, Wednesday morning at 1 am.

Here’s what happened:

Tuesday night into Wednesday there were two EF-2 tornadoes that touched down near Bowling Green.  One was in Smiths Grove and destroyed someones barn and silo.

Then there was another one near Penrod, Ky.  This one tore apart a barn and left debris in the trees.

Picture taken by Landon Hampton and posted on Facebook. This is damage from the EF-2 tornado near Penrod, KY.

There were numerous storm reports on Wednesday morning and the NWS went out and surveyed the damage, deciding what was caused by winds or a tornado.

Lets move on to the other drastic change.  We are back to the cold temperatures of January.  Another cold front is moving in tonight and is bringing with it snow.

We could see up to 1 inch of snow when all is said and done.  We will see sunny skies on Friday after the snow and clouds move out, but then there is more.  ANOTHER COLD FRONT will move into the area on Saturday bringing with it another shot at some accumulating snow.

If you look at the 540 line (red dashed) in the top right and bottom right pictures,  that is showing the line of where snow would form to the north of.  So we are going to see some light snow on Saturday.

The Weekend:

Friday: Sunny skies with highs in the mid 20s.  The wind chill could be in the single digits.  Bundle up!

Saturday: We will see a chance of snow showers in the morning before noon, then that will mix with some rain.  Could see some slick spots on the road.  Less than a half of inch is possible.

Sunday: Mostly sunny, highs in the low 40s.

Everyone enjoy the warmth this afternoon, because it is all about to change.  The front will pass through overnight tonight and with that it is going to bring the chance of severe weather and colder temperatures after the front.  The CAPE is slightly higher than previous models have shown, which hints to us more instability in the atmosphere.

With the amount of CAPE, it is possible to see some small hail and isolated tornadoes.  Along with these threats, we may see strong winds move through Bowling Green tonight ahead of the storm and with the storm.  The moisture axis is right through Bowling Green and surrounding areas.  This adds to the instability of the atmosphere.

The strongest winds are also near South Central Kentucky.  We could see wind damage as we wake up tomorrow morning.  Downed trees and power lines will most likely be the main threat.

We are going to see periods of heavy showers and rumbles of thunder tonight.  Here is the radar for overnight tonight.  The cold front will bring heavy rain and thunderstorms between 2am and 4am. This makes it more of a hazardous situation because it is coming overnight.  1-2 inches of rain is expected through the storm.

The model below is showing a high vorticity value in the top left box and the front just to the west of Bowling Green in the top right box.  This is indicator of strong storms tonight. This is showing the change in wind speed with height and is showing upper-level divergence in the atmosphere, which is why there is a possibility of isolated tornadoes and a supercell thunderstorm.

As the front passes and we go through the day on Wednesday, temperatures are going to decrease.  We should see our highest temperature in the morning on Wednesday, and we will cool off as the day goes on.  The colder temperatures will come behind the cold front.  Then we are back to seasonal temperatures for the remainder of the week.

Today: We will remain cloudy for the day and temperatures will near 70.  Our record is 74 degrees and was made in 1975.

Tonight: Make sure you stick to your television or radio for the up to date weather information.  The strong line of storms has the possibility of bringing small hail, strong winds, and isolated tornadoes across South Central Kentucky.

Tomorrow: We will see cooling temperatures as we go through the day tomorrow.  Clouds will move out leaving us with partly cloudy skies in the afternoon.  We will see more seasonable temperatures before tomorrow is over.

I am sure everyone is in the need of a break from the winter weather that we have seen the past couple of days.  Well the break is on the way.  Temperatures will make their way into the upper 50s and into the 60s this week.  This is about 20 degrees above average.  But with these milder temperatures comes the chance of severe weather in the middle of this week.

This is showing the severe weather potential for Tuesday night into Wednesday.  Bowling Green is on the edge of a slight severe potential for the week.  This would come in the form of a squall line, which has the possibility of damaging winds.  In the picture below, it shows a squall line moving through the area overnight on Wednesday.

 If you take a look at the top right image, this is showing that there will be a cold front that comes through Tuesday night into Wednesday.  If you take a look at the bottom right image, we may see about one inch of rain as the system moves through.  Also, Bowling Green is near the heaviest amount of rain.  The winds will be strong during this time frame.   After the cold front comes through, temperatures will be back to reality, with temperatures back in the 30s.

Week Forecast:

Today- We have a slight chance for rain as we go through the day today.  Temperatures in the upper 40s.

Monday– Another slight chance for showers and highs near 60 degrees.

Tuesday-Showers, temperatures in the mid and upper 60s.  Later in the evening, we will hear rumbles of thunder as a squall line moves through.  There is a possibility of damaging winds.

Wednesday-Showers linger throughout the day and temperatures will drop.  Our high will be in the morning, so we will be back to seasonal temperatures by the afternoon.

Thursday-Mostly sunny, with highs in the upper 30s.

Friday-Mostly sunny, highs in the upper 20s.