WKU Meteorology

As mentioned yesterday we would have to keep a close eye on the temperatures here in south-central Kentucky to see what type of precipitation would fall tonight.  Temperatures have risen to 35 at the airport as of 1’oclock  Meanwhile the Kentucky mesonet shows temperatures hovering around the freezing mark.  The key is that dewpoints are still near 30 degrees and as precipitation begins to fall the temperature will cool down toward the dewpoint temperature by a process called evaporative cooling.  That’s not so say that temperatures will cool to 30 but they may fall just below freezing.  If this indeed  occurs sleet and freezing rain will fall across south-central Kentucky.  Some areas could receive up to 0.25 inches of ice, especially from I-65 and to the northwest.  Some sleet accumulation is also possible but I think that will be further to the north and west where less melting will occur in the atmosphere.  Rain will probably fall more so in places such as Simpson and Barren counties but will likely be mixed with sleet and temperatures could cool enough to turn rain into freezing rain.  The temperatures will need to continue to be monitored as the precipitation moves in.

Summary:

-Precipitation will move in between 2 and 4.

-Precipitation may start as plan ole rain mixed with some sleet in locations such as Warren, Simpson, Allen and Barren Co.  However precipitation will likely start and continue as sleet and freezing rain in locations further north and west such as Logan, Butler, Edmonson, and Grayson Counties.

-Temperatures should cool a degree or two after precipitation begins which could allow for locations such as Bowling Green to dip below freezing and thus allowing precip to change to freezing rain.  The amount of sleet mixed in may also bring down temperatures.

-Temperatures will need to be monitored closely as a degree or two will mean the difference in an Ice Storm and just a cold rain.

-An Ice Storm is possible with up too 0.25+ inches of ice which could bring down some tree limbs.  Over an inch of sleet is also possible especially northwest of a line from Russellville to Morgantown to Edmonson Co.  These same areas stand the best chance at an Ice Storm, including NW Warren Co but all areas in south-central KY will likely be impacted by freezing rain and sleet.

After a weekend of warm temperatures and rain we now find ourselves in the low 30s with sleet falling in the area.  A very strong cold front blasted its way through the commonwealth yesterday bringing in much colder temperatures.  At one time Sunday afternoon temperatures dropped 15 degrees in an hour.  The front has since moved to our south and east but has stalled generally from Virginia to the New Orleans area.  Meanwhile and upper-level disturbance is moving across the southern plains which is pulling moisture up and over this boundary.  When you have moisture being pulled up and over a cold airmass at the surface, winter weather enters the conversation.  Not just winter weather but usually a wintry mix including sleet and freezing rain.  This is setting up ahead of the disturbance across the mid-south and is impacting us here in south-central Kentucky.  Currently a large area of precipitation exists from Mississippi into our area bringing with it mainly sleet.

Radar imagery around 4 pm shows a large area of snow, sleet, and freezing rain from MS in southern KY.

Snow has been reported on the northern end of the precipitation but its the freezing rain and sleet in Mississippi and Tennessee that have made headlines today. With temperatures hovering between 30 and 33 across the area and with dewpoint temperatures in the 20s, precipitation is falling as snow and mainly sleet.  Precipitation amounts should be very light and with roads still warm after this weekends record warmth any impacts should be minimal but there could be some issues on bridges.  All precipitation should move out quickly this evening and we should be left with just cloudy and cold conditions by 9 pm.  That likely won’t be the end to the wintry weather however.  Yet another upper-level disturbance will move in tomorrow and once again moisture could be pulled up and over the cold air we have in place at the surface.  Models are indicating that this event could be more significant however with around 0.25 of an inch of moisture.  Right now models indicate that this would fall as a very cold rain but I fully expect sleet at times and if temperatures remain below freezing longer than expected some freezing rain is possible too.  Models show that BG would reach a high of 39 but I don’t expect that to occur either.

NAM model simulated reflectivity for 6 pm Tuesday. Temperatures at this time are expected to be in the low to mid 30s.

I think temperatures will struggle to reach 35 tomorrow with precipitation and clouds.  The models forecasted a high from 35-40 today and we only very briefly hit 34.  Thus I expect a mix of sleet, freezing rain, and a very cold rain tomorrow.  Depending on the temperature we may see some travel problems especially late in the day as the sun angle decreases.  Precipitation should move out late tomorrow evening and we return once again to just cloudy and cold conditions.  As for the rest of the week, there could be a few peaks of sun by Wednesday but several clouds will stick around as well.  By Thursday models greatly disagree on the movement of an upper-level disturbance moving through the southern US.  Most models agree that the system will pass off to our south and thus only bringing in a few clouds to our area while the NAM indicates that some rain or even a wintry mix could move in.  Until any of the other models bring the system further north, I’ll leave this out of the forecast but it does at least need monitoring.  I’ll give an update on this system during the midweek update.  One thing is certain in the long term and that is the COLD.  How cold and how long remain unknown but it seems likely that very cold air will move in by early next week which could mean lows into the teens and highs struggling to reach the freezing mark.

Daily Forecasts:

Tonight: 20% chance of a sleet/snow possible before 8 pm otherwise cloudy and cold with a low near 27.  North winds from 5-10 mph.

Tuesday: 70% chance of a wintry mix of sleet and freezing rain, and rain mainly after noon.  Some minor sleet and ice accumulations are possible.  Cold with a high near 35.  Rainfall around 0.25 in.  North to northeast winds from 5-10 mph.

Tuesday Night: 40% chance of a wintry mix before midnight, otherwise cloudy with a low near 28.  North winds 3-8 mph.

Wednesday: Mostly to partly cloudy with mainly high clouds.  Still cool with a high near 44. West to northwest winds 5-10 mph.

Thursday: Partly cloudy with a morning low near 30 and a high near 47.

As mentioned 11 WKU meteorology/land, weather, climate majors traveled to Austin, TX for the Annual American Meteorological Society (AMS) meeting.   Dr. Mahmood, WKU professor of geography/meteorology, also made the trip to Austin with his family to attend the meeting.

The 11 WKU meteorology students that attended the 2013 Annual AMS meeting.  Photo courtesy of Andrew Dockery.

Students left Bowling Green last Friday morning and after staying the night in Dallas, TX made their way to Austin Saturday morning just in time to attend the Student Conference.  The Student Conference featured keynote speakers Dr. Steve Lyons, Meteorologist in Charge at NWS San Angelo, TX (formerly of The Weather Channel)

Dr. Steve Lyons, MIC at the NWS San Angelo, TX office, was a keynote speaker at the AMS Student Conference. Photo courtesy of Andrew Dockery.

and Dr. Francis Slakey of Georgetown University.  The Student Conference as provided an opportunity for students to attend breakout sessions that varied from individuals in the private sector, those in research, those in the public sector including National Hurricane Director Dr. Rick Knabb, and individuals associated with graduate school.  All told there were numerous speakers from all sectors of the meteorological field at the student conference that specifically directed there talks and gave advice to meteorology, climate, hydrology  etc… students.  A career fair and graduate school reception also provided and excellent opportunity for students to connect with possible employers as well as professors and students from graduate schools.

To end the student conference, students from across the nation presented research in a poster session.  WKU was well represented with 3 research posters being presented.  Andrew Dockery and John L. Thomas presented a poster entitled “A Case Study of a Rare Long-Track EF-3 Tornado in Eastern Kentucky” which was a result of research with Dr. Durkee done during the 2012 Summer Research Seminar.  Other WKU students Tyler Binkley, Ryan Difani, Micheal Flanigan (not pictured), and Quentin Walker also worked on the research.

Tyler Binkley, Andrew Dockery, John L. Thomas, Quentin Walker, Ryan Difani, (from left to right) and Michael Flanigan (not pictured) with their research poster presented during the Student Conference at the 2013 AMS Annual Meeting. Photo courtesy of Will Paschall.

Emily Yates presented her research poster entitled “March 9 Hawaii Kona Low System Case Study” which was research she did for her Weather Forecasting and Analysis Project.

Emily Yates with her research poster during the student conference at the 2013 Annual AMS Meeting. Photo courtesy of Will Paschall.

Finally Chris Johnson presented a research poster entitled “15th Anniversary of Mid-South Severe Weather Outbreak.”  This research project was a result of Dr. Durkee’s Fall Research Seminar.  Others working on this research were Emily Yates, Micheal Flanigan (not pictured) and Quentin Walker.

Quentin Walker, Emily Yates, Chris Johnson (from left to right) and Michael Flanigan (not pictured) with their research poster during the student conference at the 2013 Annual AMS Meeting. Photo courtesy of Will Paschall.

Starting Monday the main conference was underway with numerous talks throughout the week.  Some favorites of students were talks on tornadoes, hurricanes, and lightning.  Aside from the talks there were opportunities to meet and network with other professionals.  Officers of the WKU AMS/NWA student chapter attended a chapter officers breakfast on Tuesday morning.  An exhibit fair featured numerous professionals in the field with which students could meet with.  The Doppler on Wheels (DOW) vehicle was also on display with researcher Dr. Josh Wurman present.  Finally not to be left out was some great Texas food enjoyed by the group including an excellent “Tex-Mex” location in downtown Austin and some fantastic barbecue from The  Ironworks Barbecue also located in  downtown Austin.  The trip concluded  with

Chili and a brisket barbecue sandwich from “The Ironworks Barbecue” in downtown Austin, TX. Photo courtesy of Andrew Dockery.

the AMS banquet on Wednesday evening.  The group left out Thursday morning to make the trip back to Bowling Green.  Also not to be left out, WKU student Austin Boys served as a student volunteer throughout the conference.  The group thoroughly enjoyed the conference and we are already making plans to attend next year’s annual meeting in Atlanta, GA.

We’re back!  For those that noticed the lack of forecasts this past week it was because 11 WKU meteorology students (including your forecaster) traveled to Austin, TX for the 2013 American Meteorological Society Annual Meeting.  I’ll post a recap of the trip later but for now back to the weather.

When I last posted, we we’re talking about a warm up in the days to come and warm up it did.  Bowling Green reached 70 degrees on Friday which broke the old record of 68 set in 1916!  Meanwhile temperatures have hovered in the upper 60s to near 70 again today.  Besides the warmer weather, rain has been the other story.  We have seen a little over an inch of rain this past week in the county and more heavy rain is on the way.  This will bring up the threat for flash flooding and minor river flooding.  The NWS has issued a Flood Watch for Warren Co and most of south-central Kentucky through tomorrow evening as up to 3+ inches of rain is possible.  Currently there is a low pressure in NE Texas with a warm front extending from the low through Arkansas and into Indiana.  The aforementioned low pressure will ride along the front and will pass to our north but a cold front extending south from the low will pass through Sunday.  This system will be the focal point for the heavy rain through Sunday night.  Very heavy rain will be possible especially around midday tomorrow as moist air will be streaming in from the Gulf.  A very strong low-level jet between 50 and 60 knots will be responsible for bringing in such moist air.

NAM forecast precipitable water values Sunday morning are in excess of 1.5 inches over most of central Kentucky.

Precipitable water values will be over an inch and a half for several hours during the middle of the day tomorrow.  With the intense rainfall flash flooding will be a very real possibility especially because of the amount of moisture already in the ground due to our recent rains.  In total between 1.5-3 inches of rain will be possible across much of south-central Kentucky.  It can’t be ruled out that some locations could see more than 3 inches.  The official forecast from the Hydrometeorological Prediction Center is for between 1.5 and 2.5 inches of rain.

The HPC rainfall forecast indicates 1.5-2.5 inches of rain over south-central KY.

Behind the front which will pass through Sunday MUCH colder air will move into the state.  The cold air mass that is currently over much of the Midwest (which provided the cold air for the Broncos vs. Ravens game in Denver) will be moving in (though it won’t be as cold as it is at the game).  Temperatures will begin falling by early afternoon and temps will be in the 40s by 6 pm.  Temperatures may be cold enough tomorrow night before the precipitation ends to allow the rain mix with or transition to sleet or even freezing drizzle.  Overall any wintry precipitation should be light and shouldn’t create any impacts.  Colder air will be in place for much of the early part of the week with temperatures generally in the 40s for highs.  The front which will pass through here Sunday will stall across the southeastern US and a couple of disturbances along with this front will create at least the chance of precipitation both Monday night and Tuesday.  Models disagree on how much if any precipitation will fall in south-central Kentucky and thus this system bears watching.  Furthermore with the colder air in place especially at night some of the precipitation could be of the wintry type.  Check back in for the early week update on this system.  Furthermore another system next Friday could also bring a chance of some wintry weather or it could just be all rain but time will tell.

Daily Forecasts:

Tonight: FLOOD WATCH  Cloudy skies and warm with temperatures steady in the upper 60s; low near 66.  50% chance of rain after 1 am.  Windy with south winds 15-22 mph.

Sunday: FLOOD WATCH  Rain, rain will likely be heavy at times and some thunder is possible.  High near 65 early but temperatures will drop throughout the day into the 40s by 6 pm.  Winds will switch from the SW to the NW throughout the day; winds from 8-15 mph.  Rainfall totals between 1.5 and 3 inches.

Sunday Night: 50% chance of rain before 10 pm with a slight chance thereafter. Some sleet or freezing drizzle can’t be ruled out.  Temperatures cooling to a low near 28.  NNW winds from 5-10 mph.

Monday: Partly to mostly cloudy and cool with high near 38.  North winds from 5-10 mph.

Tuesday: Mostly cloudy to cloudy with a 40% chance of light rain possibly mixed with sleet.  Chilly with a low 29 and a high near 40.

The sun has made a return to south-central Kentucky after a few days of clouds and rain to start the week.  Temperatures have slowly warmed as well and it seems as though highs will trend to being in the low 40s for the remained of the week and into the weekend.  High pressure will be in control over most of the central US for the end of the week.  With the high centered to our west, north and northwesterly winds will keep the cool air across Kentucky.

NAM forecast surface temperatures/MSLP Saturday afternoon. With the high pressure centered to our southeast, a warm-moist southerly flow will be over KY. The cold front located over the Plains will pass through Sunday morning bringing in another wave of colder air.

By this weekend however the high will push to our east and thus a southerly return flow around the high will bring in warmer air and more moisture.  This return flow along with a shortwave disturbance in the mid-levels of the atmosphere will be enough to bring at least increased cloudiness by Saturday afternoon/night.  A few sprinkles/flurries are possible Saturday evening/night though any precipitation should be light if it falls at all.  Another wave of colder air is likely behind a cold front that should pass through Sunday morning; meanwhile high pressure will once again build in.  As that high moves east early next week a more significant warm up appears likely.

Daily Forecast:

Tonight: A few clouds but otherwise mostly clear and cold with low around 22.  Light NW winds.

Friday: Sunny skies with a high near 43.  West winds from 3-10 mph.

Friday Night: A clear cold night with lows around 23. Light and variable winds.

Saturday: Partly cloudy skies early before becoming cloudy by noon.  High around 45.  South winds at 3-6 mph.

Saturday Night: Mostly cloudy to cloudy skies with a 20% chance light shower/snow shower or sprinkle/flurry.  Low around 30. Southwest winds from  2-6 mph.

Sunday: Partly cloudy and cooler with a high near 40. Winds switching from the SSW to the NW; winds from 6-12 mph.

Monday: Mostly sunny skies with a high around 44.

Another “trace” of snowfall was recorded over the weekend for Bowling Green, but there has still been no measurable snowfall this winter.  Despite a very cold upcoming week to start the new year, any snow chances are slim to none.  Rain chances on the other hand are quite high at least through tomorrow morning.  Currently an upper-level trough extends across the Rocky Mountains with an associated shortwave in the four corners region.  This disturbance along with a weak surface low in Oklahoma is setting off a large area of showers over much of the south-central US.  This disturbance and thus the rainfall will be moving east and into our area.  Light rain should begin this afternoon and continue off and on into the overnight.  Rain should become steadier around midnight just in time to ring in the 2013.  The best chance for a steady rainfall will be between midnight and 6 am.

RAP model simulated reflectivity for midnight tonight. Notice rain will be falling to ring in the new year for most of Kentucky.

The front associated with the system will be moving very slowly by tomorrow morning thanks to a strong high pressure just off the southeast coast. This will allow a continued area of rainfall Tuesday morning from Warren Co south and east into Tennessee; with that said some of the highest rainfall totals should be to our south and east.  Nonetheless between a quarter and half inch of rainfall is expected here in south-central Kentucky.  The first day of the new year will be cloudy day with a chance of a showers primarily before noon.  North to northwest winds on New Year’s Day will bring in a reinforcing shot of colder air which will keep temperatures cool.  Highs likely won’t reach 40 Tuesday and Wednesday.  The cold weather will be the main story this week after tonight’s rainfall as the rest of the week will be rather uneventful.  High pressure will in Tuesday night and keep the weather calm and cold.

The Hydrometeorological Prediction Center’s national forecast for Wednesday shows high pressure in control over the central US. Also note the low pressure and cold front near the US/Canadian border. This weak front should pass through Thursday and bring in another wave of cold air late in the week.

Another weak cold front will likely push through Thursday only to bring in more cold calm weather.  The front will lack moisture and thus it should be a dry front on Thursday.

Looking long term models are indicating that the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) will become positive which would tend to allow warmer air to move in.  It does indeed appear as though warmer temperatures will be in store by next weekend and highs may approach 50 by early next week.

Daily Forecasts:

New Year’s Eve Night: 90% chance of rain. Chilly with a low around 37.  Light SE winds.  Rainfall between 0.25-0.40 inches of rain.

New Year’s Day: 50% chance of rain before noon with a 30% chance of a few showers or even a flurry thereafter.  Cool with a high near 39.  North to northwest winds from 3-8 mph.

Tuesday Night: Mostly cloudy becoming partly cloudy by morning.  Cold with a low around 25.  North winds from 3-8 mph.

Wednesday: Partly to mostly sunny with a few high clouds.  High near 36.  Light north winds.

Thursday: Mostly sunny with a morning low near 24 and high around 41.

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 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.

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.

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 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.

What a wild weather day!  From 60 and heavy rain to 35 and light snow; the biggest story of the day however… the wind!  Bowling Green had sustained winds up to 35 mph and the peak wind gust was 53 mph!  Other locations in the state had gusts up to 60 mph.  What really made yesterday’s winds impressive was there longevity.  Since the start of the 20th (12 am) 32 hourly reports at Bowling Green had gusts equal to or higher than 25 mph including 18 hours straight from the 11:53 am report (20th) to the 4:53 am report (21st).  The winds will die down continually overnight and may even be calm by morning.  Light winds combined with a clear night will allow temperatures to drop a good deal.  Temperatures will fall into the low 20s.  Warmer days are ahead however, this despite the official start of winter today.  The upper-level trough that has moved into the Ohio Valley behind yesterday’s storm system will push out and high pressure will build in at the surface.  The clockwise flow around the high pressure will bring a warm return flow into Kentucky which will allow temperatures to rise.  This high pressure will be in control of our weather through Saturday.

NAM forecast for 00Z on the 24th (6 pm Sunday). Notice rainfall beginning in southern KY. Also note the return flow (red arrows) bringing in warmer and more moist air. A high pressure in Canada is set to settle into the northern Plains (blue arrow).

By Sunday warm air will be brought in by the return flow and a shortwave disturbance will move closer to the area along with a weak surface low.  This should be enough to spark a few showers Sunday evening especially into Sunday night.  Anywhere from a tenth to a quarter of an inch of rainfall is possible by Monday morning.

It’s behind this weak system that the weather gets interesting.  Behind the surface low which will move through on Monday, winds will switch from the northwest as a cold Canadian high pressure system will try to move in making for a cooler Tuesday (Christmas Eve).  Meanwhile another disturbance will move out of the Rocky Mountains and develop a surface low near the Gulf Coast.  A Canadian high pressure in the northern Plains and a surface low developing near the TX/LA coast creates a perfect set-up for a mid-south snowfall.  Yes, we stand a shot at our first winter storm here in south-central Kentucky Christmas night and Thursday morning (26th).  The problem is where will the surface low track?  Models have continually flip-flopped on the exact track of the low from run to run.  The surface low track is vital to whether we receive rain or snow or a mix.  If the surface low tracks to our south and east over parts of Alabama and GA/E TN we would receive all snowfall here in south-central KY.  The next to last (18Z) run of the GFS model gives us this solution.  However, if the surface low tracks from Mississippi and then very close to us it would bring primarily rain for us here with only a chance of some light snow behind the system.  The morning (12Z) run of the GFS model gave us this solution.  Finally the latest (00Z) run of the the GFS model showed a solution in between the two which could bring rain, changing to a mix and then snow.

Three runs of the GFS model, the 12Z (morning) run, 18Z run (next to last), and 00Z (latest) run all valid for 12Z (6 am) on Dec 26th.

What can you take away from this?  The possibility is there for our first winter storm here in south-central Kentucky next week, but it’s just that a possibility.  Computer models continue to disagree on the exact track of the low pressure and it’s the track of the low which will determine if we get rain or snow.  Significant snow accumulations by KY standards are possible and likely somewhere in KY but how much and exactly where are still unknown.  Two things seem fairly sure though, a system will impact the mid-south the middle of next week and colder air will be moving in.  Until then though, we’ll be watching as we get closer to the time of this system.  Enjoy a nice Saturday!

Daily Forecast:

Tonight: Clear and cold; low near 21.  Less windy with winds WNW between 5-15 mph decreasing between calm and 5 mph by the morning.

Saturday: Sunny skies and a little warmer with a high near 44.  WSW winds from 3-8 mph.

Saturday Night: Low near 28.  Mostly clear night with SW winds from 3-8 mph.

Sunday: Warmer with a high around 50.  Clouds increasing early to make for a mostly cloudy day.  30% chance of a few showers after noon.  SSW winds from 7-14 mph.

Sunday Night: Cloudy with a 60% chance of rain.  Rainfall between a 0.10-0.25. Winds switching from the SW to the WNW from 4-9 mph. Low near 44.

Monday: 40% chance of rain in the morning otherwise mostly cloudy with a high around 50.