Discussion:
The first half of the week has been dominated by warm temperatures with a good mix of sun and clouds throughout. The high today (Wednesday) climbed to 86 degrees at the Bowling Green Airport easily making this the warmest day of the year thus far. In fact we our high was 18 degrees above the average for this time of year. The warmth will come to a screeching halt tomorrow as a very strong cold front will make its way through the area. This front could pack a punch in more ways than one… not only will much colder temperatures move in behind the front but severe storms could also move in along the leading edge of the frontal system.
Currently a 1004 mb low pressure system is located near the St. Louis, MO region with a warm front extending to the east into southern Ohio and the strong aforementioned cold front extending south through Arkansas and into Louisiana. Both of these fronts have been the focal points for severe storms today. Tornadoes have been reported in both Arkansas and Missouri along with numerous other severe weather reports that continue to come in at this hour. Severe weather watches extend along these areas of thunderstorms including a tornado watch for parts of western Kentucky. This is all headed toward the south-central Kentucky area but the question is how will it effect us?
Current thinking is that a line of thunderstorms will continue to move in our direction along and ahead of the front some of which could be severe. In fact the Storm Prediction Center has outlined all of south-central Kentucky in a slight risk for severe storms. Areas along and east of I-65 have been included n the 30% probability area.
A slight risk of severe storms has been outlined by the SPC for all of south-central KY for Thursday. This includes an area of 30% probability east of I-65.
Several things are coming together to create this possibility:
- A diffluent flow is present in the upper-levels which should help create synoptic scale lifting
- A strong closed area of low pressure with an associated area of vorticity is located over at 500 mb will be moving over the Midwest
- Around a 50 kt low-level jet will be advecting warm moist air from the Gulf of Mexico as well as helping to increase low-level shear
- Warm and moist air at the surface will allow for at least weak to moderate instability of around 250 – 500 j/kg
- A strong cold front will create lift
- Finally an area of 35-45 knot surface to 500 mb bulk shear
NAM forecast reflectivity (left), CAPE (center), and MSLP/winds/temp (right) for around 1 pm Thursday.
These conditions are all setting the stage for possible severe storms with threats of hail and damaging winds. It appears that directional shear and even speed wind shear will be minimal and thus the threat for tornadoes is also small. This however does not rule out the possibility of a spin up tornado along the squall line much like what we had in late January near Smith’s Grove in Warren Co. If any storms are able to initialize ahead of the squall line, these storms would also pose an increased risk of severe weather as well but these storms are not expected to be widespread, if at all, in our area. Overall though, expect a line of storms to move in between 9 am and 1 pm that could very well contain bowing segments which could lead to strong to severe winds. Some hail is also possible with these storms. Lastly and not to be outdone is the flash flooding potential as 1 to 2 inches of rain is likely and it could fall very quickly within thunderstorms.
SPC day 1 Total Precipitation indicates 1 -2 inches of rainfall possible in south-central Kentucky.
After the storms pass through rain will continue into the evening before ending. Colder air will make its way into the area as well as temperatures will drop into the low 40s by Friday morning. Our high Friday will be much cooler as well only reaching the upper 50s to near 60. Saturday morning temperatures will likely drop into the upper 30s and some frost is possible. We’ll make a nice rebound this weekend however as conditions clear and temperatures warm back into the 60s for Saturday and the 70s by Sunday. Data is currently suggesting a return to the 80s by early next week.
In summary expect:
- A line of strong to possibly severe storms to pass through the area tomorrow.
- The timing of these storms should be between 9 am and 1 pm for south-central KY
- The main threat will be damaging winds with bowing segments in the line of thunderstorms, hail and isolated tornadoes are also possible.
- Heavy rain will accompany thunderstorms and 1 -2 inches rain is possible by tomorrow afternoon. Flash flooding is possible is association with the thunderstorms.
Daily Forecasts:
Thursday: Thunderstorms and rain are likely; some storms could be severe and rainfall between 1 and 2 inches is possible. Cooler with a high near 74 early before dropping into the 60s throughout the afternoon. Winds will be breezy from 10 – 20 mph.
Thursday Night: Rain will have ended but skies will remain overcast. Cool with a low near 41. West winds from 5 – 10 mph.
Friday: Cooler with a high of only 59 under mostly to partly cloudy skies. Winds from the west a 8 – 18 mph.
Friday Night: Frost possible with a low near 35 under partly cloudy skies. Winds will be light to 8 mph.
Saturday: Mostly sunny skies a warming up with a high around 64.
Sunday: Mostly sunny with a morning low in the low 40s and a high in the mid 70s.