Highlights

• Approaching low pressure system will bring clouds Thursday night
• Severe weather threat on Fri, with more moderate/heavy rain possible.
• Highs in mid 50′s on Saturday, returning to the 70′s by Monday.

Forecast
As convection and severe weather in Oklahoma and Missouri continue overnight, expect high clouds to start streaming into the area overnight. Lows tonight will only get down in the mid to lower 50′s under cloudy skies. Friday, conditions are favorable for thundershowers, perhaps with some severe storms later in the day. A surface low pressure system will approach our area on Friday, with winds turning out of the south-east throughout the day. This will help to bring ample moisture into the region, and bring a good chance of rain and thundershowers for Fri morning. With the approaching system, wind fields and cooler heights aloft are supportive of stronger thunderstorms for the afternoon. Because of this, the Storm Prediction Center has placed South-central Kentucky under a slight risk for severe weather Tomorrow.

However, severe potential will be limited by early morning thundershowers, with temperatures trying to rebound throughout the day. Should we get ample sunshine are severe threat would increase. Regardless, the main threat appears to be heavy rain falling on already saturated ground, with widespread 2 inch rain totals and continued river flooding is of concern.

Thunderstorms should come to an end in the late evening as a cold front associated with the aforementioned surface low crosses the region. Saturday looks to be cool and raw with rain ending in the morning and high temps struggling to reach the mid 50′s. A return to 70′s is expected by Monday.

Highlights
-Upper level trough keeping temps down on Thursday.
-Disturbance will bring slight chance of rain on Thursday night and Friday.
-Ridging and southwesterly flow returning by Sunday.

Forecast
Some clearing will take place behind yesterday’s precip on Thursday, however it looks to be mostly cloudy under northwest flow, with a trough dug out of the eastern US. General cloudyness and northwest winds on Thursday will keep high’s in the upper 40′s. Thursday night there is a slight chance for light rain as a disturbance moves through the flow allowing for some precipitation. Low temps will be in the mid-30′s. Friday continues a chance for rain, however the trough should begin to lift and temps will increase as the airmass begins to modify. Highs will be in the mid 50′ s on Friday with lows in the low 40′s. The same can be said for Saturday with the exception of clearing and partly sunny skies. Further out, temps begin to moderate Sunday into Monday as a warm front passes through our area Sunday night, bringing temperatures into the 70′s on Monday. This will be short lived however,A as a low pressure system is predicted to impact the area with thunderstorms on Monday.

HIghlights
- Continued Cool Temperatures
- Rain Chances Tues into Wed
- Warm up expected next weekend

Forecast Discussion
Currently the upper level impusle that affected our weather last night is moving out of our area. Sky’s should begin clearing today as this impusle quickly moves east. Today looks drier, however still cool, with highs near the 50 degree mark. Tonight will also be dry as Bowling Green is on the edge of ridge of receding surface high pressure. It will again be a chilly night with low termperatrues of around 33. The next system that will affect our sensible weather should be in the form of a low pressure system that will be forming in western Texas. A trough of low pressure should begin to enter our area on Tues. increasing rain chances, with the more constant precipitation occuring on Tuesday night. This rain shouldnt be terribly heavy, however cooler temperatures on Tues night may support a mix of rain and snow well north of our area. This will not affect Bowling Green, and even areas well north of here would have a minimum impact as ground temps are too warm in late March. Temps on Tues should reach in the Mid 50s with rain chances increasing throughout the day.Tues night will be all rain for us with a low around 38. Rain chances dwindle on Wed, but temperatures will remain cool, with a high around 47 under cloudy skies. The weather will remain cool, with a warm up expected late this weekend.

Highlights:
-Major rainmaker on tap for Thursday
-Cooler temperatures on Friday
-Active pattern setting up for next week

Forecast:
Warm front will move north past Bowling Green early Thursday Morning, bringing warmer temperatures and raising dew points. Moisture will be streaming northward in front of a center of low pressure that will deeping in Oklahoma. By noon this front will stall somewhere near the Ohio River and a sheild of precipitation will spread in coverage across Kentucky. By later in the evening, the low will ride up along this boundary and bring another round of heavy precip. Most of Kenucky is set to recieve widespread rainfall amounts of 2″+. The axis of heavier precipitation will reside along the Ohio river, where the greatest forcing exists along the stalled warm front. A potential exists in southern Kentucky for thunderstorms (with a small possiblility of severe) with heavy rain and strong winds being the main threat. Instability (energy) will be minimum at best, so as of now only thinking there will be a few rumbles of thunder and heavy rainfall. A cold front will andvance eastward, with this center of low pressure, and precipitation should come to an end Fri. morning. Temperatures on Fri will remain cool with highs only reaching the upper 40′s and lows Fri. night in the mid 30′s. Saturday looks to be dry and seasonalby warm with highs in the middle 50′s and lows in the 40′s. With a chance of rain returning on Sunday.

Highlights:
-Warm air and southwesterly flow bringing in higher temperatures
-Chance of showers increasing through the day on Monday.
-Cooler temperatures on Tues.

Discussion:
After warm frontal passage on Sunday, southwesterly flow will continue into Monday bringing with it some Gulf of Mexico moisture and a good chance of showers. A low pressure system will move across Indiana Monday night, dragging behind it a cold front which will drop temperatures Monday night into the low 30s.This front should be a focusing mechanism for precipitation, so expect better coverage towards the evening on Monday. Some of the rain showers could be mixed with flurries as cold air filters in Tues. morning, but no impact is expected from this as ground temperatures are too warm. Tues. temperatures will be much cooler with partly cloudy skies, and high temperatures in the upper 40′s.Temperatures increase on Wed. as southerly flow returns in the form of a warm front. This ahead of a late week low pressure system that will affect our area on Thurs. High temperatures on Wed. should top out in the upper 50′s.

Forecast for this evening

After evaluating the more reliable 0z (0z and 12z runs use observed upper air data from the U.S. radiosonde network) suite of model runs, there remains favorable continuity with the last set of model runs with only a sharpening of the QPF gradient. Snowfall totals for Monday seem to be consistently forecasted as 2 inches along the KY/TN border where counties 1 tier north of those getting an inch or less of the white stuff. The snow really drops off north of Nashville with totals there being 3 to 4 inches if you happen to be traveling.

Forecast soundings from the RUC, observed in bufkit, have about a half of an inch of snow in Bowling Green, while areas to the south and east receiving just a touch more. Feel that this is good due to continuity of forecast products with the SREF and the fact that any snow that initially falls will fall as virga (precipitation that evaporates before it reaches the ground). This forecasted sounding from the RUC shows precipitation beginning to accumulate in Bowling Green @ 5a.m.

All of that aside, With freezing ground temperature in place any snow will readily stick and untreated roads will become snow-covered. So take it slow tomorrow morning as the onset of precipitation looks to begin at about 2 a.m. Monday morning at the KY/TN border as seen below in the RUC rapid high resolution rapid refresh (HRRR) simulated radar reflectivity.

For any Kentuckians left without snow from this first shot, most of us will luck out with a second chance on late Monday night into Tuesday. Even though this first surface system is more potent and will drop more snow in the south, its lagging upper level energy will swing through the
Midwest Monday evening, and cause the formation of a surface low in TN that will quickly move northeastward.

There is some disagreement on the exact track, but regardless there will be widespread light snows across most of Kentucky. For now it appears that the further north with this second system, the more snow you will receive. 1-2 inches will not be out of the question for central Kentucky, while northward crossing the Ohio river into Indiana, those areas could receive up to 4 inches. There is still some deviation in model solutions with this second impulse of energy, so no need to carve it in stone yet.

As of now onset of precipitation with the second system will likely start around midnight Monday night and the accumulating snow showers will have moved out by Tuesday afternoon. Snow flurries will continue off and on through Wed. due to wrap around moisture and a cold northwest flow behind the system.

In summary for Bowling Green:
Tonight: Snow flurries after midnight light snow in the early morning
hours, low 24

Monday: High 32, light snow before noon total accumulation <1″,
chance of snow flurries the rest of the day

Monday night: Low 28 snow develops after midnight .5″

Tues: High 32, light snow, new snow .5″

Wed: Mostly Clear, Cold HI=25 low=13

Fri: Mostly Clear, HI=31 low =21

Following this weekends cool blast and a more active southern stream, A significant winter storm will impact the deep south tonight through Tuesday. However, for our neck of the woods, most of the heavy accumulations will remain down south.

A deep 500 mb trough in place through the central U.S, with an embedded shortwave trough with translate northeast across the south over the next 24-46 hours. The resulting surface low pressure cylcone will track along the gulf coast, where Warm air advection and a strong low level jet will advect ample moisture in the deep south.

This is a classic overrunning situation where southernly winds in front of a system ‘overrun’ with respect to density and height, cold air that is already in place at the surface. Places such as TN where there is a sufficently deep cold air mass in place will remain all snow, where as the deep south will experience a wintery mix with heavy ice accumulations a particular concern for Alabama.

The graphics below depict the 850 mb temperatures and the forecasted precipitation for 6 am central time tommorow.

The NAM(top) is slightly more aggressive in bringing in more moisture than the GFS(bottom). However both models as well as other model suites are in good agreement on the track of the surface low. The important thing to note is the sharp forecasted precipitation gradient as moisture tends to fall off very quickly north of say Nashville. As far as snow totals are concerned in South Central Kentucky; anywhere from a dusting in central Kentucky to 2 in of snow along the KY/TN border are possible.

For snow lovers, another chance of accumulating snow is forecated for Tuesday morning as an upper-level wave and its surface reflection pass through our region. So make sure and stay tuned for updates.

Even further out things look to get brrrrrr. cold as an truly artic airmass may make it as far south as kentucky next weekend. Should be an exciting week for weather!

Boy what a difference a few days makes. Latest model runs now provide quite a drastic picture shaping up for this weekends weather. Both the European and GFS as Well As The North American Mesoscale Model, are in pretty good agreement of a more northerly storm track. Confidence has grown in the Model solutions as the system is now in the United States upper air network.
In General the system has taken a more northerly track with a surface cyclogenesis developing in the plains today, and the low moving northeast into the great lakes. Saturday looks to be all rain, and alot of it, as most areas should pick up anywhere from .5 to 1 inch of rain with embedded elevated instability. So, a rumble of thunder, especially into TN can not be ruled out. In the wee hours of the morning as the cold front pushes through, rain should change to snow from west to east as the front pushes through, expect only minor accumulations before dry slotting quickly cause a cease in snow. During the day on Sunday however, snow showers and flurries will be on the increase as wrap around precipitation in the northwesterly flow will cause a fetch of moisture to come off of lake michigan providing Bowling Green with some flurries and the bluegrass region of KY with some minor accumulations.

Here is an image from the 12z model run of the GFS illustrating this.

All in all, it will turn drastically cooler on Sunday and Monday with highs in the mid-20s on Sunday and lower 20s on Monday. Overnight lows those nights will also struggle to get into the teens as artic air infiltrates the area.
For Saturday expect up to one inch of rain in Bowling Green with a high of around 50, and after the front moves through Bowling Green should pick up one inch of snow or less, while areas to the northeast should recieve more, with maximum amounts in the blugrass region of ky of around three inches.

For those who are interested, the KY division of emergency managers are holding there first annual weather workshop. Topics range from weather awareness and safety, to impacts of El niño Southern Oscillation’s effects on KY weather. The target audience is anywhere from emergency managers and meteorologists, to agricultural specialists. Information about the event being held today and tommorow here in Bowling Green can be found at the link below.

http://kyem.ky.gov/conferencesandworkshops/weatherworkshop2010.htm

Guest speakers include Dr. Greg Forbes from the Weather Channel, members of the National Weather Service and faculty from WKU. Everyone is invited, including prospective meteorology students as one of the talks is on programs available at ky universities.

Shortwave and resulting vorticity maxima, coupled with some jet dynamics, is allowing just enough lift for some light showers in northern KY. For Bowling green, it will be a cloudy day with skies clearing overnight. High pressure will also return tonight, that with clearing skies will allow temps to fall tonight. Todays high should reach 51 with tonight’s low reaching 35 under calm winds.

After today’s stereotypical November day temperatures will begin to moderate for the weekend as a large trough develops over the Western US, keeping the real fall weather away from South-Central Ky for the near term.