December 7, 20214 yr There is a chance for strong to severe storms Friday evening into the early morning hours on Saturday. A low-pressure system will move towards the northeast just west of Kentucky. It will draw moisture from the gulf into Kentucky. Dewpoints will rise into the mid-60s west of I-75. East of that point dew points will rise to the mid-50s. Temperatures will rise to the mid to upper 60s. A trailing cold front will move southeast towards Kentucky. This will bring a trough of cold air that will move in behind the cold front and slam in the warm moist air. This is where the line of strong to severe storms will form and move southeast across Kentucky. The timing for the main line of storms looks to be between 10 pm EST Friday night till 12 am EST Saturday morning. The following EHI shows the potential energy for the strong to severe storms. This one shows the possible conditions for supercell storms to form. I will post and update in the morning.
December 8, 20214 yr Author Wednesday morning update: The Storm Prediction Center has most of Kentucky west of I-75 in a category 2 Slight Risk Area. East of I-75 portions of Kentucky is in a category 1 Marginal Risk Area. Strong to severe storms with damaging winds and possibly brief tornadoes will be possible. There will be periods of windy conditions Friday night and Saturday. Gusts over 40 mph are possible. Some of the storms will contain moderate to heavy rain with accumulations of 1-2". Update later today.
December 8, 20214 yr Author Wednesday evening update: Strong to severe storms with damaging winds and isolated brief tornadoes will possible Friday night into the morning hours on Saturday. Wind gusts over 40 mph are possible. Localized flooding and river flooding could also occur. As of now the main line of storms looks to enter western Kentucky around 10 pm EST Friday. Then traverse southeastward across Kentucky. Both the GFS and NAM show this. NAM GFS The conditions that could be conducive to the formation of severe storms as of tonight is greater than it was yesterday. My main area of concern for possible tornadoes will be west of I-65. The NAM is the only model of the two that shows the Significant Tornado Parameter. This doesn't mean one can't form east of that area just that the condition appears to be more conducive for the formation of tornadoes west of I-65. I will be keeping a close eye on the conditions for Friday night into the day on Saturday. The next update will come tomorrow afternoon. Of course, if data warrants it I will post earlier. conditions
December 9, 20214 yr Author Thursday morning update: As I expected last night the potential severe weather threat has increased even more overnight. The Storm Prediction Center has increased the severe weather categories for most of Kentucky. Almost all of Kentucky west of I-65 is now under a category 3 Enhanced Risk Area. The Louisville area is not included as of this time. Louisville and most of the area between I-65 and I-75 is now under a category 2 Slight Risk Area. A small section east of I-75 is under a category 1 Marginal Risk Area. This significant tornado parameter map shows how the threat has increased since last night. Severe Storms overnight Friday into Saturday with localized damaging winds and isolated tornadoes. Heavy rain rates may cause local flooding problems during thunderstorms. Everyone should have a way to receive severe weather alerts especially since this will be an overnight event. Check back later today for updates.
December 9, 20214 yr Author Thursday afternoon update: It appears that the severe weather threat for Friday night into Saturday morning is growing. Severe thunderstorms capable of producing several tornadoes and scattered to numerous damaging wind gusts are possible mainly Friday evening and overnight . A strong tornado or two are now possible. Since this appears to be a nocturnal event everyone should have a way to receive severe weather announcements that may need to wake you up. The Storm Prediction Center has extend the category 2 Slight Risk Area a little further northeast than it did this morning. The Cincinnati/NKY area is now included. I will post a more detailed forecast this evening. Everyone should take to time to go over the emergency action plant.
December 9, 20214 yr Author Thursday evening update: A powerful storm system will impact Kentucky Friday night into Saturday morning. A squall line will accompany this system with areas of damaging winds, possible tornadoes, and heavy rain, and flooding. Since this will be an overnight event, be sure to have ways to receive warnings while you are asleep. If you live in a vulnerable location such as a mobile home, consider finding lodging elsewhere with sturdier shelter Friday night. Bring in or secure any outdoor decorations and holiday decorations. The impacts that could be felt from this system wind damage to power lines trees and structures. Isolated brief tornadoes. The tornado threat is the greatest west of I-65. For western Kentucky, the storms could hit Friday evening and overnight. Damaging winds and tornadoes are the greatest concern. A few tornadoes could be strong. Large hail and locally heavy rain are also possible. The following GFS and NAM radars are from 10 pm/9 central EST Friday night to 1 pm/12 central Saturday afternoon. A different breed of danger. Tornadoes in winter frequently occur at night. Move very fast, often 50-70 mph! Spin up suddenly, even a good tornado warning will usually have less than 5 minutes lead time. Everyone should be preparing now or during the day on Friday for this event. The next update will come in the morning.
December 10, 20214 yr Author Friday morning update: The Storm Prediction Center has expanded the category 3 Enhanced Risk Area to include all of Kentucky west of I-65. A large section of the area between I-65 to I-75 is under a category 2 Slight Risk Area. The latest thinking is scattered supercells could develop by 10 pm/9 central EST. Then track northeast within a very strongly sheared environment. With the thunderstorms not expected to develop until after dark daytime heating will not be a contributor to the destabilization of the atmosphere. Even with that forecast conditions will be favorable for supercell development. With dew points expected to rise into the lower 60s,longer-lived a few strong longer lived tornadoes seem possible. While conditions will support supercell development through sunrise, there will be a propensity to evolve into a squall line with eastward movement. Tornadoes and wind are the primary threats. Some may see more than one severe storm pass through their area. The Storm Prediction Center has increased both areas for both tornadoes and damaging wind chances. The HRRR radar shows the possible storm development mentioned above. I will be posting updates throughout the day when information warrants it. This is a nighttime severe weather event everyone should be preparing now along with having a way to receive warnings that will wake you up if you are asleep.
December 10, 20214 yr Author I just received the following email from the National Weather Service-Louisville where I'm a registered SKYWARN spotter. Quote Good morning Partners, The forecast continues to show a round of nighttime storms overnight tonight into Saturday morning ahead of an approaching cold front. This system has a little more punch to it than the one earlier this week, and confidence continues to remain high that any storms that form could produce damaging winds as well as a possible tornado. Unfortunately the timing of these storms will be when most people are asleep. Mobile homes are particularly vulnerable to strong winds and even relatively weak tornadoes. Vulnerable populations should have ways to receive warnings that will wake them up out of a sound sleep may wish to consider finding sturdier shelter well before the storms hit, such as at a friend's or relative's, to stay at Friday night As always If you have any questions or concerns, contact us via email, NWSChat, or give us a call. Sincerely, National Weather Service, Louisville
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