New Year Rain

Today has been a beautiful day with a high temperature of 38. A surface high pressure has settled in the area underneath upper level ridging. Aloft, the ridge is rapidly breaking down and moving east because of a very deep positively tilted trough over Southern California. This trough has very impressive winds downstream which will be intensifying to upwards of 160 knots into the week as it traverses east. These strong winds and significant positive vorticity advection at 500 mb indicates substantial upper level support for areas downstream of this trough, which is currently the central and southern Great Plains. The timing for precipitation for our area is looking most promising Tuesday morning, which corresponds to the highest 700mb vertical velocity values over the Ohio River valley. Because of the stated dynamics aloft, the surface high will quickly track east overnight, producing a return flow over the area for tomorrow, bringing Gulf moisture and slightly warmer air into our area. A majority of the moisture will reside to the south and west of our region, since our area is near the upper extent of advection as seen below. This will lead to lower precipitation values for the event.

12Z (6 AM) 1/1/13 Tuesday NAM 850 mb dewpoints (deg. C), winds (knots), and heights. Notice the high pressure in the Atlantic east of Florida pumping in Gulf moisture across the gulf coastal states.

For Tuesday, there are two surface features coming into play. There is a weakening cold front from the NW crossing our area, and there is also a weak surface low pressure system that will stay along the Louisiana gulf coast. This gulf low will help to pump additional moisture into the southeast and north into our area, where the cold front will act as the lifting mechanism. The timing of the front will be around noon. Expect slight warm air advection associated with the return flow Monday afternoon into Tuesday morning. The freezing line will be slightly to our north, but with the presence of warm air advection, any precipitation should fall as rain along the frontal boundary.
 

NCEP GFS mean sea-level pressure, 6 hour precipitation (inches), 1000-500mb thickness at noon Tuesday 1/1/13. 

Notice the GFS output above indicating most precipitation associated with the frontal passage and gulf low to the south and west of our area with the 540 thickness line (a rough indicator for the rain/snow boundary) to the north and west of our area. Behind the front into Wednesday morning, expect skies to clear and temperatures to drop. Wednesday should be nice, but cool with a surface front entering the area from the northwest on Thursday. This feature will need further monitoring, but is not showing significant strength or availability of moisture.

Days at a Glance:

Monday (New Years Eve):  High: 41  Low: 27  Precip: 30% chance of rain  Wind: S 5-9 mph

Tuesday (New Years Day): High: 36  Low: 29 Precip: 80% chance of rain  Wind: S 7-10 mph switching to NW 8-10 mph late. Precipitation will range .20-.40 in total for Monday night into Tuesday depending on the amount of moisture that makes it to our area and strength of the weakening cold front.

Wednesday: High: 33  Low: 21  Precip: 0% chance  Wind: NW 5-8 mph

Forecaster: Austin Boys

More Rain & Another Winter Weather Tease

As Wednesday's major winter storm was wrapping up across the area, light snow fell and officially a trace of snow fell in Bowling Green; just a winter weather tease so to speak.  Behind the system also came cold air.  Highs on Thursday only reached 36 degrees at the Bowling Green-Warren County airport under an overcast sky.  Speaking of overcast skies we really haven't seen much of the sun since last weekend and we won't see the sun again until Sunday.  That's nearly a full week without sunny skies.  We'll be seeing more than just cloudy skies by this afternoon/evening however.  Drizzle or light rain should start sometime around 1 pm and then continue into the evening and overnight.  Rainfall will be fairly light but steady and anywhere from a quarter to a half of an inch of rainfall is expected by morning.

The Hyrdometeorological Prediction Center's total precipitation forecast shows around a half an inch across south-central Kentucky. Some of this will be rainfall while some of it will fall as sleet and snow.

Temperatures today will reach the low 40s but they will continually cool during the evening and overnight.  With cooling temperatures and continued precipitation, a chance of a wintry mix and eventually snow exists after midnight.  Sometime between midnight and 3 am is when sleet and snow should begin to mix with rain and eventually a change to all snow is expected sometime early Saturday morning.

High-Resolution NAM model showing the rain/snow line bisecting south-central Kentucky around midnight tonight. This is not a forecast but rather just one computer model.

At this time no significant accumulation is expected and for this reason it will be just another winter weather tease for south-central Kentucky.  Nevertheless, up to an inch of accumulation is possible by Saturday morning.  This is not to say we will see an inch as some locations especially further south likely will see no accumulation but areas further north and west (Butler & Ohio Co etc...) stand a decent chance at some minor accumulations.  Snow chances and totals will increase as you go north and along the Ohio River some locations could receive 2-4 inches of snow.  In fact a Winter Weather Advisory is posted along and to the northwest of the Western Kentucky Parkway.  Snow showers/flurries should continue throughout much of the day Saturday and at the very least it will be another cloudy cold day.  Cool WNW winds at 8-12 mph will keep highs in the low to mid 30s.  Clouds should finally begin to clear out Saturday night as a surface high pressure moves in; these two factors combined with light winds will make for a very cold start to Sunday with lows in the upper teens.  The sun will make a return to the area by Sunday with the high pressure overhead but it will still be chilly with highs only near 40.  The sunshine will be short lived however as another system is poised to impact the area Monday afternoon into New Year's Day.  At this time the system should bring predominately liquid precipitation but there is a possibility it could bring yet another winter weather tease.

Daily Forecast:

Today: Cloudy skies with a 80% chance of light rain after 1 pm. High around 40.  Southeast to south winds at 3-8 mph. Around 0.1-0.25 inches of rainfall.

Tonight: 90% chance of precipitation which will start as rain and mix with and change to snow by morning.  Low near 30. Around 0.1-0.25 inches of rainfall.  Up to an inch of snowfall possible.  WNW winds from 3-8 mph.

Saturday: 50% chance of snow showers/flurries.  Otherwise cloudy and cold with a high near 34.  WNW winds at 8-12 mph.

Saturday Night: Mostly cloudy skies will become mostly clear.  Cold with a low around 19.  Northwest winds from 4-9 mph becoming light by morning.

Sunday: Mostly Sunny with a high around 39. Winds will be light and from the SW to south.

Monday: Morning low near 29 with a high around 41.  Cloudy with a 40% chance of afternoon showers.

Forecaster: Ryan Difani

Heavy Rain Tonight... Snow Tomorrow!

A Winter Weather Advisory has now been issued for Warren County and all of south-central Kentucky until 6 pm.  Heavy rain fell overnight with 1.01 in at the Warren Co mesonet site, and just under an inch at the Bowling Green/Warren County airport.  Rain is no mixing with sleet and snow and a full transition to sleet/snow is occurring.  Current radar imagery shows a moderate band of snowfall just west of and moving into Bowling Green.  Furthermore continued sleet and snow is possible into the afternoon.  Up to an inch of accumulation is possible across the county mainly on grassy surfaces.  Accumulation on roads will be minimal if at all and thus travel should not be greatly impacted.

Moderate snowfall band in the western part of the county is set to move into Bowling Green.  Radar image from 9:58 am.

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Christmas has turned out to be cold and cloudy here in south-central Kentucky, but at least the cold weather makes it feel more like Christmas right? The clouds are ahead of a major winter storm now starting in the southern plains.  Snow is falling in Oklahoma, even as far south as Dallas, TX and icing is occurring in Arkansas.  Meanwhile Tornadoes have already been reported in east Texas and there are numerous Tornado warnings in LA/MS.  So how will this storm system impact us here in south-central Kentucky?  It looks like the heavy snow/blizzard conditions will remain just off to our west.  Blizzard warnings have been posted for much of western KY with a winter weather advisory now extending from just north of Louisville down to Central City and Hopkinsville.

Current watches and warnings across central Kentucky as of 3:40 pm.

In these areas rain will transition to a wintry mix and will eventually switch to all snow sometime Wednesday morning.  Some light snow is likely even for much of south-central Kentucky including Bowling Green by mid-day Wednesday.  First however rain will move in and the winds will increase.  NE winds will continually increase this afternoon into the evening.  Overnight winds will be from 18-28 mph with gusts up to 35 mph.  Winds will be strongest between 10 pm and 6 am.  Rain should start across our area sometime around or just after 6 pm this evening and will continue into the early morning hours of Wednesday.  Rainfall will be heavy at times and 1.00-1.50 inches of rainfall is likely in the area, some areas may receive up to 2 inches of rain.

The Hydrometeorological Prediction Center's precipitation forecast. Note around an inch plus in south-central KY.

Rain will probably move out between 6-9 am tomorrow as the "dry slot" of the storm system moves in.  Meanwhile temperatures will be dropping from the mid 40s early to the low 30s throughout the day as cold air is ushered in by strong 10-20 mph NW winds.  Some precipitation should wrap around the back side of the low pressure system and into south-central KY including BG just around noon on Wednesday and continuing into the evening hours.  This will likely be rain which will mix in with and switch to snow after 1 pm.  At this time this shower/snow shower activity appears to be light and scattered and thus little accumulation of snow is expected.  Some areas may pick up around a half inch of snow.

18Z High Resolution NAM reflectivity indicates light rain changing to light snow in central Kentucky by 1 pm.

Behind the storm system cold air will continue to move in.  Skies should be mostly sunny by Thursday though it will be cold with highs only in the upper 30s.

Tonight: Rain, heavy at times.  Windy; winds from the NE from 18-28 mph with gusts to 35 mph.  Temperatures warming to near 45 by morning.  Rainfall between 0.75-1.25 inches.

Wednesday: Rain in the morning coming to and end by 9 am.  70% chance of rain/snow showers after noon.  Winds switching from the NW at 10-20 mph.  Temperatures cooling from near 45 in morning to the low 30s by 6 pm.  Rainfall less than a quarter of an inch and snowfall around a half an inch is possible.

Wednesday Night: Cloudy skies with a few snow flurries possible early otherwise cold with lows near 26.  Winds from the NW at 6-12 mph.

Thursday: Partly cloudy and cool with highs near 38.

Forecaster: Ryan Difani

Cloudy Cool Christmas... Rain or Snow Christmas Night?

It's been a nice first weekend of winter here in south-central Kentucky.  As a matter of fact yesterday's high of 55 in Bowling Green put us about 10 degrees above average for this time of year.  Changes in our weather pattern look to bring the warmer than average trend to and end by the end of the week however.

Below Average Temperatures are Forecast by the Climate Prediction Center for this Weekend into Next Week for much of the Nation including Kentucky.

Cold Canadian air will take aim at the Ohio Valley behind a storm system moving though this Wednesday.  Temperatures will initially begin cooling off this afternoon as a cold front will pass through.  Behind the front cooler air will settle in from the north which will make for a cool Christmas Day. It seems as though clouds will stick around for most of today with some clearing overnight behind the front.  The clouds will quickly create overcast skies again on Christmas Day with the next storm system which will be approaching from the southwest.  There will be no snow, so if you've been dreaming of a white Christmas, just keep dreaming, next Christmas is only 366 days away!  Back of the next storm system, the last blog post mentioned the possibilities of our first real winter storm of the season the day after Christmas.  I also said that the models didn't have a good handle on the track of the storm system and that the track of the low would mean all rain, all snow, or a mix here in south-central Kentucky.  Well the models have come into some better agreement, enough to say that it seems very unlikely that we will receive snow here.  Models have come into better agreement that most of the snow will fall just to the north of the Ohio River from SE Missouri to Indiana.

Probability of 2 inches of Snow or more from the Hydrometeorological Prediction Center shows that any significant snowfall will remain just north of the Ohio River.

As we near the time of the system and because the models have come to at least some degree of certainty it seems highly unlikely that the models would shift so far south as to give south-central KY/Bowing Green a good chance at significant snow.  However, some snow may wrap around the back side of the low pressure system and thus there is a chance for light snow Wednesday afternoon.  So if you are in want of snow you'll need to travel north and west to find some snow. For those traveling north to the Little Caesars Pizza Bowl in Detroit to cheer on the WKU football team be aware that heavy snow is likely in Detroit Wednesday morning. So if no snow here, what kind of weather will come our way?  Well you guessed it, it looks like a rainy Wednesday is ahead.  Rain should actually start sometime Christmas evening, around or just after 6 pm.  Rain will continue overnight and some rainfall could in fact be fairly heavy.  It appears as though much of the area may receive at least an inch of rainfall by the time the rain is ending midday Wednesday; much of the mid-south could receive closer to an inch and a half.

The Hydrometeorological Prediction Center's Precipitation Forecast for the next 3 days. Notice the Forecast of 1.00 to 1.75 inches of Rain in South-Central Kentucky.

It does look like that at least some light snow may fall Wednesday afternoon/evening but little to no accumulation is anticipated at this time.  As for the end of the week, skies should clear briefly Thursday before another storm system impacts the area Friday night/Saturday.  This system will too bare watching as precipitation may be of the wintery type.  Temperatures will be cool with highs in the 30s and 40s.

Daily Forecast:

Monday: Mostly cloudy with 40% chance of light rain/drizzle especially before 10 am.  High near 52.  Winds between 3-8 mph switching from the SW to NW.

Monday Night: Clouds clearing to become partly cloudy with a low near 34.  Light northwest to northeast winds.

Christmas Day: Increasing clouds in the morning to make for a cloudy day.  Cool with a daytime high around 45.  40% chance of rain late.  Northeast winds from 6-12 mph.

Christmas Night: Rain some of which could be heavy at times.  Temperatures warming overnight to near 50.  Winds from 10-20 mph switching from the east to the southeast and then to the southwest.  Rainfall between 0.75-1.00 inches.

Wednesday: 60% chance of rain before 10 am with a 40% chance of a showers changing to snow showers by the afternoon. Temperatures will fall throughout the day with temps near 50 at 6 am but only in the upper-30s by 6 pm.  West to west-northwest wind from 10-20 mph.

Thursday: Partly to mostly sunny with morning low near 28 and high of only 38.

Merry Christmas All!!

Forecaster: Ryan Difani

Thursday to Bring Rain, Colder Temps, High Winds & Snow Flurries??

The last couple of days have been very nice here in south-central Kentucky, sunny skies have dominated and highs reached the mid 50's yesterday and the low to mid 60's today.  However....  changes are on the way!! Currently a major storm system is developing over the southern plains which could bring severe weather to our west overnight in parts of Arkansas and Missouri.  Meanwhile a blizzard with heavy snows will occur on the north side of the system from Nebraska to Wisconsin.  This system will begin to impact us here in southern KY as early as this evening in the form of increased cloudiness and stronger winds.  Current satellite imagery shows increased cloudiness moving into the area from the west.  Rain will soon follow as rain and storms should break out in the southern plains by 6 pm.  The storm system overall will quickly progress from the panhandle of Oklahoma to near Chicago, IL by tomorrow afternoon. As it does, several different impacts will be felt here in south-central Kentucky including rainfall, high winds, much cooler temperatures and finally, snow flurries???

Rainfall:
Models are consistent in showing the precipitation moving in between 3 am and 5 am.  Rainfall will then continue steadily thereafter into Thursday morning.  There will be some very limited instability in south-central KY but nonetheless a rumble of thunder cannot be ruled out during the morning hours.  Rain will fall steadily throughout most of the morning as will the temperatures.  Rainfall totals will likely be anywhere between 0.25 and 0.5 inches.

The Hydormeteorological Prediction Center's 1-2 Day Precipitation Forecast.  Note Around a Half an Inch in South-Central Kentucky.

Temperatures:
Temperatures will start out Thursday in the mid to upper 50's. However, they will be dropping and will do so all day Thursday.  By noon, temperatures will be near 50 but will begin falling more rapidly as the cold front should push through around that time.  Winds will switch out of the west ushering in the cold air.  By 6 pm temperatures will have fallen to around 40 and the strong winds will make it feel even colder outside.

Winds:
Speaking of the winds they will be very strong.  There is a WIND ADVISORY for Warren County and all of south-central KY from 3 am tonight until 9 am Friday.  Tonight the winds will be increasing with winds out of the south between 10 and 20 mph.  They will continue to increase and will be anywhere from 20 to 30 mph tomorrow especially around and just after noon behind the front as the winds switch out of the west and southwest.  Gusts will be greater than 35 mph and may be as high as 50 mph between noon and 4 pm Thursday.

NAM model forecast for 3 pm Thursday.  Note that the for the most part precipitation has pushed to the east.  The black lines indicate equal lines of pressure and the closer these lines are to each other the higher the winds.  Also the 850 zero degree line (blue line intersecting KY) indicates that cooler temperatures will be moving in and with some lingering precipitation flurries are possible.

Snow Flurries??:
As if the day would not be eventful enough weather wise, flurries or even light snow will be possible as moisture wraps around the storm system.  The best chance for flurries/snow showers will be between 6 and 9 pm and chances will increase as you move north and east of Warren Co.

Finally, skies will slowly clear into the early morning hours of Friday but cloudy skies most of the night will be enough to keep temperatures from getting too cold.  Nonetheless, Friday morning lows will be in the upper 20's.  Skies will remain clear Friday but temperatures will remain cool and winds will once again be strong.  Winds Friday will be from the northwest from 15 to 25 mph with gusts as high as 30 mph.  Highs will struggle to get above 40.  Clear skies will remain through Saturday morning and winds will finally become much lighter.  With lighter winds that may go calm and clear skies, Saturday morning temperatures will dip into the low 20's.  Next chance of rain won't be until Monday.

Daily Forecasts:
Tonight: Increasing clouds with rain by morning with some thunder possible.  Temperatures may drop into the low 50's before holding steady or even warming to around 56.  Winds will increase out of the south from 10 to 20 mph.

Thursday: Rain with some thunder possible before noon.  Rainfall totals will be between 0.25-0.50 inches.  Strong winds switching from the south early to the west by the evening; winds will be from 20 to 30 mph with gusts 40 mph+.  Temperatures will fall from around 56 in the early morning hours to around 40 by 6 pm.  Flurries or a light snow shower is possible in the evening.

Thursday Night: Cloudy skies with a few flurries possible early.  Still windy with winds from the west at 15 to 25 mph.  Clearing late with a low near 27.

Friday: Sunny skies and still windy with northwest winds from 15 to 25 mph with gusts as high as 30 mph.  Cool with a high near 40.

Friday Night: Clear skies with wind slowing to near calm by morning.  Cold with a low near 22.


Forecaster: Ryan Difani

Stormy start to the week...Nice Tuesday ahead.

An upper level low with associated surface low moved to the northeast through parts of Illinois and Indiana Monday afternoon/evening.  Thunderstorms developed ahead of the approaching cold front as storms strengthened while producing heavy rains, gusty winds, and hail.  Mostly pea to dime size hail was reported across southern Indiana and central Kentucky where some spots received enough hail to turn the ground white or even caused piles or drifts of hail to form.  A few locations did receive severe hail of 1 inch in diameter. Along with severe hail reports, heavy rainfall seemed to be the other threat from the storms that impacted the region.  Heaviest rainfall occurred over parts of Central and South-Central Kentucky where recorded rainfall amounts ranged from 0.50 - 1.00 inch.  

Louisville NWS  24-hour Precipitation through Tuesday am, December 18, 2012.

Top Photo: 1'' Hail in SW Scott County, KY.
Bottom Photo: Pea-size Hail in NE Louisville Metro.
(Reports and Images from Louisville NWS)

Once the front tracked through the region by late afternoon, early evening hours on Monday, slightly cooler and gusty conditions prevailed.  Cloud cover continued to diminish throughout  the evening and overnight hours leaving a cooler, but windy Monday night.  

Looking ahead for Tuesday, clouds should continue to clear out by morning hours leading to mostly sunny skies with highs reaching the low to mid 50's, especially west of I-65.  A weak ripple in the WNW upper level flow will pass just to the north of our area tonight with little impact on the weather.  Effects could tighten the the southwest gradient as the region remains near the external boundary of the surface high over the deep south.  This will help keep overnight temperatures slightly above average with lows projected in the upper 30's to around 40 degrees.  

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Wednesday: Mostly Sunny skies. High near 65ºF. South winds 10 - 15 mph. 

Wednesday night: Expect increasing clouds with showers and possibly a thunderstorm after   midnight.  Low: 55 ºF. Breezy conditions expected with south winds 15-20 mph.

Thursday: Showers likely before 9am, then scattered showers through the early afternoon hours. Cloudy conditions expected with gradual clearing by evening hours.  Breezy, with a south wind 20-25 mph. 

Forecaster: Chris Johnson

Weekend Ahead

Currently there is an upper level trough over California and Nevada which will set the stage for us this coming weekend.  Vorticity associated with the trough will help to deepen and move the trough into the Warren County area.  High pressure is dominating our area which means Relative Humidity values are low over the southeast United States meaning that the air is not saturated which will allow the temperatures to plumit tonight down to 28.  For tomorrow, be sure and have a jacket.  Your morning commute and bus stop forecast calls for a temperature of 26 at 7:00 A.M. with mostly clear skies with winds out of the south due to the high pressure over the area.  This will help the temperatures to climb tomorrow with a high of 55 with light winds out of the south at 5mph.  The trough will continue to push east and become negatively tilted by late afternoon due to a diffluent flow occuring over the southeastern U.S.  A jet max moving through the area due to influence by the subtropical jet, will cause the trough to define more as we move into Friday Night.  The winds will be from the south Friday night causing temperatures to be warmer with a temperature at 10:00 P.M. of 43. 

Saturday: High 63    Low 39

Sunday:   High 65    Low 55






Forecaster:  Tyler Binkley 

Wet Weekend Ahead!!

Rain today, rain tomorrow will be the general theme of this weekend.  This is due to several disturbances passing through our area between now and Monday when a strong cold front will finally pass through.  Until that time we’ll have a cold front approaching from the northwest will which begin to stall out near the Ohio River Valley.  Because the front will begin to stall to our north we’ll see continued rain chances along with warm temperatures.

A cold front near the Ohio River Valley will be the focus of scattered areas of rainfall the next couple of days. Surface forecast from the HPC for Saturday.

Today and Saturday by no means look to be wash outs.  For today, the majority of the rain will be focused north of south-central Kentucky near the Ohio River which is closer to the front but at least a few scattered showers are likely in our area.  On Saturday rain seems more likely in our area as a band of rainfall should set-up in south-central Kentucky along the front which will slowly drift closer to our area and even pass through during the evening hours.  Rain chances will be highest into the afternoon but this rainfall shouldn’t be terribly heavy with generally less than a quarter of an inch of rainfall possible.

Total rainfall forecast from the HPC through Wednesday morning.  Rainfall totals in Kentucky/Tennessee are expected to be between 1.50-2.00 inches of rainfall.

By the time we move into Sunday another cold front will be approaching from the west ahead of a deep trough in the upper-levels which will be moving east.  As this system approaches the front which had stalled near our area will begin to lift back the north as a warm front.  This should enhance rainfall chances with the front near our area especially Sunday morning as the front pushes back through our area.  Sunday should be a warm day as we once again challenge record highs in Bowling Green.  Highs should be near 70 and could reach the record high of 71 set in 1952.  The warm weather will break into early next week however as the aforementioned strong cold front pushes through bringing much colder temperatures to our area.  Furthermore as the cold front moves through Sunday night/Monday morning rain will be likely.  Rainfall is expected to fall steadily for several hours and thus the area could pick up as much as an inch of rainfall by midday Monday.  Some of the models disagree with the timing of when the rainfall will move out Monday and thus this will be monitored to see how forecast models can come into agreement.  Meanwhile temperatures will fall throughout the day on Monday with temperatures expected to be in the 30s by the afternoon.

Daily Forecast:

Today: High: 66  Cloudy with a 70% of a few scattered showers through the day with around a tenth of an inch of rainfall possible.  Winds from the south-southwest from 10-15 mph.

Saturday: Low: 58  High: 67  Cloudy skies with and an 80% chance of showers especially in the afternoon.  Rainfall should be less than a quarter of an inch.  Winds from the southwest switching to the northeast late at 5-10 mph.

Sunday: Low: 54  High: 71  Cloudy skies with an 80% chance of rainfall especially before noon.  Rainfall around a quarter of an inch.  Winds out the south-southwest from 10-15 mph.  More rainfall moving in overnight Sunday night; overnight/Monday morning rainfall totals could approach one inch.

Forecaster: Ryan Difani

Highs in the 70s... It is December Right???

Yes, you read your calendar correctly, though it may not feel like it outside, it is indeed December.  Highs of 68 (Rec: 71) on Saturday and and high of 72 (Rec: 76) on Sunday challenged daily records for Bowling Green.  On average we should be in the low 50s for highs this time of year and thus we are 20-25 degrees above average.  The warmth looks to continue as temperatures will climb even with Bowling Green situated on the warm side of a surface high pressure system off the southeast coast.  It looks as though we will once again fall short of the record high of 78 set in 1982 as highs are only expected to be around 75.  Meanwhile skies will be mostly sunny and thus making for a phenomenal day for December.  The only drawback to the weather is that it will be blustery with winds between 12 and 18 mph out of the south/south-southwest.  Temperatures will reach the maximum for the week today however as a cold front is set to bring in cooler temperatures and likely rainfall by Tuesday afternoon.  Their could even be enough instability for a rumble of thunder.  The cold front will not be a very powerful front as it is far from the surface low pressure centered well into Canada; this will allow the front to be somewhat slow moving.  Due to this rain could fall for several hours Tuesday afternoon and thus rainfall totals could be as high as a half an inch in some places with even higher totals further south and east of Bowling Green.  The best chances of rain will be between noon to just after 6 pm when the front pushes through.

The Hydrometeorological Prediction Center's 1-2 Day QPF (Total Rainfall) Forecast.  Notice forecast rainfall totals around a half an inch in south-central Kentucky.

Behind the front on Wednesday, skies look to clear out for a sunny day as another high pressure system will work its way in from the northwest.  While temperatures will be cooler, highs near 60 will still mean that we'll be about 10 degrees warmer than average.  Thursday looks to be the coolest day with morning lows reaching the upper 20s and highs only in the mid to upper 50s due to cool winds coming in around the high pressure.  Looking longer term into the end of the week temperatures will remain above average and rain looks to enter the forecast again for the weekend as front stalls out in the Ohio Valley.

Daily Forecast:

Today: Low: 57  High: 75  A few clouds especially in the morning but otherwise mostly sunny and warm.  Blustery with S/SSW winds at 12-18 mph.

Tuesday: Low: 59  High: 68  Cloudy skies with rain moving in mainly after noon.  Rainfall totals between 0.3-0.6 in.  Chance of rain 90%.  S/SSW winds between 8-14 mph becoming NW/N in the evening between  5-10 mph.

Wednesday: Low: 39  High: 60  Sunny skies with light north winds 3-8 mph.

Thursday: Low: 28  High: 58  Mostly sunny with winds from 5-12 mph switching from the east to the SSE/S.

Forecaster: Ryan Difani

Welcoming December on a Mild Note

For the past couple of days, we have been under a dominant surface high pressure system. Currently, the upper level flow is zonal and the models show this pattern persisting into Sunday. Thus, we are going to be stuck under this stationary high pressure to close out the week. As it moves eastward, our area will begin to experience a return flow, bringing in warmer, more moist, Gulf air. With this said, expect a warming trend into the weekend with beautiful weather. Get ready to welcome in December with mid-60 temperatures!

Days at a glance:

Friday: High - 60; Low - 32
Saturday: High - 65; Low - 42
Sunday: High - 67; Low - 48

Forecaster: Austin Boys

More Cold Weather This Week

We are currently in the return flow of a surface high pressure system with a weak cold front draped diagonally across central Illinois and Missouri. The strengthening upper level support will help to push the boundary through our area early Tuesday morning. The inflow of moisture is apparent, but not very significant. There is a nose of moisture extending into western Kentucky from the Gulf of Mexico.

NAM 11/25 18Z run valid for Tuesday 11/27 03Z (9PM 11/26) showing 850mb dew points greater than 0 Deg C, heights, and winds. The nose of moisture is clearly visible as well as the frontal boundary across the Ohio River valley.

The question is whether this precipitation will be of the frozen kind, and how much.

GFS 11/26 00Z run valid for Tuesday 11/27 12Z (6AM) showing mean SLP, 1000-500mb thickness, and 6 hour precipitation in inches. The boundary between red and blue thickness lines marks the freezing line bisecting Kentucky. 

The GFS run above is showing the line of critical thickness (estimated freezing line) horizontally dividing Kentucky. Being situated near the freezing line makes determining the type of precipitation very tricky. Concerning the amount, both the NAM and GFS are concluding the precipitation at 12Z Tuesday, with the GFS calling for up to .09 inches and the NAM calling for up to .24 inches. I will stick to the lower end, since the frontal lifting and moisture inflow are moderate at best. The temperature difference on either side of the front is lacking, thus further reducing its chance of strengthening, especially at night. Right now, precipitation received is looking like rain, but I will continue to monitor and provide updates to precipitation type up to the frontal passage if needed.

After the frontal passage early Tuesday morning, a surface high pressure will settle into the region for the middle of the week bringing more of a return flow into Thursday.

Days at a glance:
Monday: High of 56, Low of 34, no precipitation
Tuesday: High of 43, Low of 22, .11 inches of rain
Wednesday: High of 49, Low of 25, no precipitation
Thursday: High of 55, Low of 32, no precipitation

Forecaster: Austin Boys

Thanksgiving Forecast....

One more warm and sunny day is expected across the area for the Thanksgiving Holiday before a cold front brings a big temperature change for the Ohio Valley region. For today, high pressure currently stretching across the region will slowly shift eastward leaving the area the last full day of sunny and warm conditions.  Highs are expected to reach the mid to upper 60's with light and variable winds from the southwest making the holiday an absolute gorgeous one.

SPC Mesoanalysis Map 500mb heights, temps, and winds valid Thursday 14Z. Ridge building over the south with the short wave trough to our north and west.

Looking ahead, a cold front will move into parts of southern Indiana late tonight while advancing southeastward near the Ohio River by tomorrow morning.  The cold front will bring  showers into the forecast as the highest coverage of precipitation looks to be just to our west.  Shower activity will become more scattered in nature as the front progresses eastward over our area.   The HPC's  latest QPF map shows a light to moderate rainfall event over the Midwest with heaviest rainfall falling in parts of Missouri and southern Illinois.

HPC's latest QPF map showing a light to moderate rainfall event over 24-36 hours.

As the front passes through Friday, some additional moisture swinging around the upper level trough may bring some scattered clouds in the north during the afternoon.  At this time, winds should begin to pick up out of the northwest behind the front with gusty conditions expected with winds up to 25 mph.  Colder air will filter in behind the front just in time for the weekend, as temperature will be noticeably cooler across the region.

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Friday: Showers likely. High: 54 Northwest winds around 10-15 mph.

Friday Night: Clearing skies and cold. Low: 28. Light Northwest winds around 5-10 mph.

Saturday: Sunny and cool. High: 41. Northwest wind around 5 mph.

Saturday night: Clear and cold. Low: 24.

Unseasonably warm temperatures to stick around....

As we start another week and head into the Thanksgiving holiday, conditions across the area are expected to be unseasonably warmer.  A fast zonal upper air flow continues across much of the eastern United States as the northern branch of the jet is located along the U.S./Canadian border, helping keep the cooler air to our north.  A weak 500 mb ridge will temporarily develop over the region today, followed by a weak trough that will slide through the Commonwealth by Monday.

HPC/NOAA short range forecast valid for Tuesday 12Z. Ridge of high pressure will build over the Tennessee Valley region as the weak trough to our west tracks eastward through the area by Monday night/early Tuesday morning.

As the low tracks through late Monday night, a slight chance for an isolated shower will exist although the main threat seems to be cloud cover.  Neither feature will have much effect on the the overall temperatures as a gradual warm up is expected through the Thanksgiving holiday.  The HPC's QPF maps below seems to show agreement as any rainfall that does occur will be light and mainly to the north of the state.

HPC's QPF precipitation forecast map valid for Tuesday 12Z. Showing areas of light precip. just to the north of the state in parts of southern Illinois and Indiana.

Highs for your Sunday will begin a nice stretch of comfortable fall time weather.  Temperatures are expected to reach the low to mid 60's here in Bowling Green under mostly sunny skies, as identical days look to follow.  Skies will remain clear for your Sunday evening as temperatures drop to around 36 degrees with calm winds expected.

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Monday: Expect mostly sunny skies. High: 64.

Monday night: Expect increasing clouds with light and variable winds from the west. Low: 43

Tuesday: Another nice day with partly sunny conditions. High:65 Light winds from the southwest around 5mph.

Tuesday night: Partly to mostly cloudy skies expected. Low: 41

Forecaster: Chris Johnson

End of the Week and Weekend Forecast

A calmer weather pattern looks to set in for the end of the week into the weekend here in Bowling Green. The biggest story will be the cooler temperatures with several mornings starting out below freezing. Conditions should remain dry Thursday into the weekend as our air remains very dry with dew points only in the 30's throughout most of the period as winds remain out of the north advecting in dry cool air from Canada. Surface high pressure will dominate the forecast period.

NAM Forecast surface temperature for Thursday morning.

Some weak upper air disturbances in the form of shortwave troughs will move through Thursday into Friday. With moisture lacking, it is not likely that we will see showers. Thursday looks to be mostly clear and sunny. Cloud cover will likely increase into Friday with relative humidity forecast to be around 60% during the day. Saturday and Sunday we should see more clear sunny conditions.

NAM forecast relative humidity for Friday 7 am. Circle shows relative humidity values around 60-70% beginning to move into Bowling Green resulting in increased cloud cover.

Forecast Overview:

Thursday: Low, 28. High, 52. Mostly clear with morning temperatures below freezing.

Friday: Low, 32.  High, 54. Clouds increasing in the morning with periods of clearing throughout the day. Morning temperature below freezing.

Saturday: Low, 34. High, 55. Warming up with clear skies.

Sunday: Low, 40. High, 55. Mostly clear skies.

Severe Weather Potential for Monday and Beginning of the Week Forecast

Hi-Res radar courtesy of Noaa.gov

Showers and storms will be moving into the Bowling Green area into Monday morning and afternoon as a cold front sweeps across the southeast. Behind the front, we will see much colder temperatures which is change from the warm up we experienced this weekend. We see highs this Sunday as of 7:00 AM EST (6:00 AM CST) in and around 5-10 degrees above normal for this time in the month of November.

Photo courtesy of weather.com showing temperature departures from normal.

As we examine the latest RUC model analysis of surface temperatures, you can clearly see the colder air mass in behind the front that will bring us the drop in temperatures for Monday and Tuesday. With the displacement of the surface low to the north west, we will see our chances of severe weather be cut down significantly. We do see a strengthened area of positive vorticity that will enhance upper level support into Monday. We also see pocket of elevated wind shear that will support lifting and provide a hail threat as upper level temperatures will be substantially cold. The main threats will be high winds and hail. The event will likely be in the nature of a squall line. Another inhibition will be the earlier in the day timing which will mean less daytime heating and energy for developing storms.  After the cold front passage, We will see our winds shift from the south to out of the north west as the front progresses through the area bringing much colder drier air into the Bowling Green area. 

RUC surface temperature analysis for 23 UTC

We are seeing winds increase throughout the day here in Bowling Green. The Kentucky Mesonet shows peak wind gusts of up to 36 MPH in Warren County as of 6:50 CST. These winds are increasing in response to the tightening pressure gradient we are seeing across western Kentucky as the system is moving eastward.

Photo courtesy of kentuckymesonet.org

Looking into Tuesday, we will see a dry out with temperatures more normal to this time of year. Temperatures could drop below freezing Tuesday morning as that cold dry air continues to funnel in from the north west. Wednesday could also see below freezing temperatures in the morning hours and chilly temperatures remaining throughout the day. Wednesday our winds will shift to the north east as surface high pressure builds in behind the previous system. A weak upper level disturbance will move towards the area deepening somewhat as it approaches our area. We can expect some light showers to possibly develop with this system. Forcing will be lacking for any severe weather/thunderstorm potential.

Forecast Overview:

Monday: High ,66. Low, 28. Winds SSE, 5-15 knots. Rainy cloudy conditions to persist throughout the day. Slight chance of strong to severe thunderstorms.

Tuesday: High, 49. Low, 28. Winds NW, 5-10 knots. Clearing conditions with a cool down. Freezing temperatures possible in the morning hours.

Wednesday: High, 51. Low, 26. Winds NE, 5-10 knots Light showers possible. Partly cloudy conditions.

FORECASTER: Emily Yates
NEXT UPDATE: 11/14/12

Showers, Major Cool Down to Start the Work Week

It is an absolutely beautiful Saturday in south-central Kentucky. A ridge of high pressure over Bowling Green (Figure 1) kept skies clear overnight, and fair weather will hang around until Sunday night. The Saturday morning low temperature was 42 degrees, and the afternoon high will be in the lower 70s. Sunday will be very similar to Saturday, with sunny skies and highs in the lower 70s. Get in your outdoor activities before the end of the weekend, folks, because Monday morning will be a return to dreary November weather.

Figure 1. 6 AM Saturday 500 mb Analysis.

 

A deep 500 mb trough (Figure 1) is located over the western United States and this feature will swing across the Plains today and into our area later on Sunday. At the surface, the pressure gradient will tighten as the mid-latitude cyclone approaches, which will provide gusty winds on Sunday. Sustained winds of 15-25 mph with gusts to 35 can be expected. The surface low pressure center is expected to track northeast towards Lake Superior and then into Canada. The system will feature a long cold front extending the full width of the U.S. (Figure 2) Current models have the front arriving Monday morning, so expect widespread showers and isolated storms overnight Sunday night into Monday morning.

Figure 2. Surface cold front at 6 AM CST Monday.

At this time, severe weather is not expected with the
passage of the cold front. The Hydrometeorological Prediction Center (HPC) is forecasting system rainfall totals in the 0.50″ – 0.75″ range through 6 AM Tuesday morning (Figure 3).

Figure 3. System total precipitation through Tuesday morning.

 

Polar air will flow into southcentral Kentucky on Monday behind the cold front, so expect the temperature to drop during the day on Monday from the mid 50s down to the upper 40s. The clouds are expected to clear out to the east by Monday evening, so Monday night will be cold. The overnight low will be in the upper 20s, and Tuesday will be sunny with highs in the upper 40s.

Bowling Green, KY Forecast:

Saturday: Sunny. High 72.
Saturday Night: Clear. Low 46
Sunday: Sunny and windy. High 72.
Sunday Night: Showers and isolated storms. Overnight low in the mid 50s, dropping throughout the day Monday.
Monday: Cloudy. High 52, dropping into the upper 40s.
Monday Night: Clear. Low 29.

Rainy, Cool Election Night, Warming Trend Starts Thursday

Tuesday has been overcast and cool thus far, with afternoon temperatures in the lower 50s.  A shortwave trough (Figure 1) is currently affecting Bowling Green’s weather, and it is expected to continue to dig southeast to further affect the forecast for Tuesday night into early Wednesday morning.  Before the clouds set in from the northwest Tuesday morning, the temperature did fall to 34 °F.  Current enhanced infrared satellite imagery (Figure 2) shows the heavier cloud cover over Illinois, Indiana, and western Kentucky.

Figure 1

Rain showers over these same areas will move southeast this evening into tonight, so expect a wet and chilly evening as you watch election results roll in.  Cloudy skies will remain through the night and through half of Wednesday.  Overnight lows will be in the lower 40s.

Figure 2

The clouds will persist until Wednesday afternoon, so expect highs only around 50 degrees.  A ridge of high pressure begins building into the region Wednesday night into Thursday, and this feature will produce warming each day into the weekend.  The NAM (Figure 3) shows surface temperatures rising back into the mid 60s by Friday.  

Figure 3

Bowling Green, KY Forecast:

Tuesday Night: Rain.  Cloudy, with a low around 42.

Wednesday: Cloudy in the morning, partly sunny in the afternoon and evening. High 50.

Wednesday Night: Clear. Low 32.

Thursday: Sunny. High 58. 

Forecaster: Evan Webb

Time Falls Back this Weekend... Will Temperatures Fall Too?

What a nice week to end October and move into November.  Skies have been generally sunny all week despite temperatures that have been slightly below average.  Temperatures should be in the mid-60s for this time of year in Bowling Green but highs have been in the 50s to near 60 this week.  As for overnight lows, Bowling Green fell to 30 degrees Thursday morning which is one of the coldest nights we’ve had thus far this fall.  There has been a gradual warm up in temperatures this week and this slow warm up should continue into this Saturday before yet another trough dips down to encompass southern Kentucky by Sunday.  As the trough and the jet stream dips to our south, slightly cooler air will once again filter into our area.  Until then however we will be on the southern edge of a trough but very near the southern edge of the jet stream as a ridge tries to build in. Generally when this jet moves to our north we warm, and when it moves to our south we cool down, thus this week with the jet stream virtually speeding by directly above us temperatures have been fairly consistent and neither warm nor cold.  

NAM 300 mb heights/winds forecast for Saturday afternoon. Temperatures will gradually warm thanks to being on the south side of jet stream but overall temperatures will be relatively neither warm or cold.

Thus until the trough dips in on Sunday expect temperatures to be warming ever so slightly. A shortwave is expected to move through Saturday afternoon ahead of the trough which could bring enough lift to create a few showers.  Rain chances Saturday afternoon are about 40% though any rain that does fall should be very light with a 0.1 of an inch of rain at the very most.  The system lacks a strong forcing mechanism as warm thermal advections and positive vorticiy advections will be very weak if present at all.

NAM forecast vertical velocity (rising air) at 7 pm Saturday. Increased vertical velocity here in southern Kentucky at this time just ahead of the shortwave (yellow dashed lines) indicates rising air and thus a chance of rainfall.

In summary, expect a very slow warm up through Saturday followed by increased cloudiness as rain chances enter the picture Saturday afternoon.  Cooler air will once again try to spill its way in by Sunday.  Looking longer term into early next week, models somewhat disagree to the strength of another trough axis moving through, nevertheless, more troughing is expected and thus cool weather will likely continue.

Daily Forecast:

Friday: Low: 40  High: 63  Mostly sunny skies with increasing high clouds late in the day.  Northwest winds will become more northerly; speeds from 4-9 mph.

Saturday: Low: 35 High: 64  Mostly cloudy skies will become overcast with a 40% chance of rain after noon.  Rain will be light with up to a 0.1 of an inch possible.  Winds from the north-northeast turning to the north at 5-10 mph.

Sunday (Daylight Savings Time Ends: Fall Back): Low: 41  High: 57  Partly to mostly sunny with light north winds between 3-8 mph.

Forecaster: Ryan Difani