#tristatewx #paducah Tuesday, June 3, 2014: Evening update. An active weather pattern is underway. Focus will be on the short term forecast (next 24-48 hours). But, anyone with outdoor plans Friday into the weekend should have a plan B. Thunderstorm activity may continue on and off into early next week. Complicated forecast unfolding for Wednesday. See the previous forecast discussion posted earlier this morning (for a longer review). Latest data has not swayed me much one way or the other on my earlier thoughts. Concerns: Severe thunderstorms are possible Wednesday afternoon into Wednesday night over all of our region. Also note that early morning thunderstorms will move into areas near St Louis over towards Mt Vernon (between 3 am and 9 am Wednesday morning). Some of those storms could also be severe. The greatest risk zone for severe thunderstorms will likely be our north and northeastern counties bounded by Randolph County, IL towards Mt Vernon, IL toward Evansville, IN and then across northernwest and northern Kentucky. The rest of the region could also experience severe thunderstorms. As you move further west and south the risk of severe weather is not as clear cut. Questions remain. That includes Poplar Bluff, Cape Girardeau, Sikeston, Carbondale, Paducah, Mayfield, Murray, and LBL. Bottom line - everyone should monitor updates as we push through Wednesday into Wednesday night. Details... By Wednesday morning a line of thunderstorms will be moving through the St Louis, Missouri area - this line will extend west into Missouri and east into Illinois. This line will be weakening, but could still pack a bunch as it moves in and through St Louis. As the morning wears on the line will weaken. Eventually the line of storms should wash out (die out) over our local counties. This will leave a boundary over portions of southern Missouri into southern Illinois and western Kentucky. This boundary should provide the eventual focus of additional thunderstorm development. In its wake this line of storms will leave a lot of clouds over our region through the day. This will complicate afternoon thunderstorm development. Typically clouds help keep instability down. However, this is part of the forecast that is uncertain. There will also be a CAP tomorrow on the atmosphere. A CAP is warm air aloft. If the CAP is stronger than forecast then that will help keep the severe weather threat in check (lower the risk). Either way, the atmosphere will likely favor severe weather tomorrow over at least portions of our region. This is especially true the further east and northeast you travel in the area. The main time frame for severe thunderstorms will be between 3 pm and 10 pm tomorrow afternoon and evening. The storms will be moving from the northwest towards the southeast. This is what we call a NW flow severe weather event. Remember that I talked about this back in March as a possibility in June into August. Area residents should monitor updated forecasts on Wednesday. Severe thunderstorm and/or tornado watches will be issued for some of our counties. The exact evolution of severe weather may not be known until we see where the overnight squall line dies out. The main concern with this event will be large hail and damaging straight line winds. I am expecting a few tornado reports in the Ohio Valley. Some of the tornadoes will be embedded within the squall line. We call these QLCS tornadoes. Heavy rain is also going to be a concern. PWAT values are going to be very high tomorrow into tomorrow night. PWAT is a measure of how much moisture is available for storms to tap into. The higher the PWAT values the heavier the rainfall totals. Flash flooding will be a concern in areas where thunderstorms train (repeatedly move over the same areas). Some of our counties have picked up 3-7 of rain in the past 7-10 days. I am forecasting pockets of 3-6 of rain over the coming 6-10 days. Some places may pick up more than that. Widespread 1-3 of rain across our entire area. Pockets of 3-6. It will be impossible to pin down what areas will experience training thunderstorms. Like what happened in Paducah, Kentucky on Monday night - very tricky to forecast training thunderstorms (thunderstorms repeatedly moving over the same counties). Longer range... There continue to be concerns that the front will stall out in or near our region on Wednesday night into the weekend/early next week. If this occurs then several rounds of heavy rain will occur over portions of our region. Again, rainfall totals could be quite high. Closely monitor update forecasts as we move forward. Pockets of flash flooding will continue to be a concern. Forecast details... Tuesday night - Partly cloudy. An isolated thunderstorm possible early. Then partly cloudy with a chance for some thunderstorms towards sunrise across our northwest and northern counties (up towards Randolph County, IL - Mt Vernon, IL). Warm and humid. Overnight low temperatures will be near 70 degrees. South winds at 5-10 mph. Wednesday - Breezy and warm. A chance for thunderstorms across southeast Missouri into southern Illinois during the morning hours. A weakening line of storms should move in from the northwest. Then a chance for afternoon showers and thunderstorms redeveloping. A few storms could produce high winds and hail. High temperatures will be in the middle to upper 80s. Southwest winds at 10-25 mph with gusts above 30 mph. Higher winds near thunderstorms. Wednesday night - A period of showers and thunderstorms. A few storms may produce high winds and hail. Mild. Low temperatures will be around 68 degrees. West/southwest winds at 10-20 mph. Much stronger near thunderstorms. Thursday - Partly sunny and less humid. High temperatures will be in the upper 70s and lower 80s. West/southwest winds at 10-15 mph.
Posted on: Tue, 03 Jun 2014 22:09:21 +0000