Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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757 FXUS64 KMRX 292312 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 712 PM EDT Mon Apr 29 2024 ...New AVIATION... .SHORT TERM... (This evening through Tuesday) Issued at 244 PM EDT Mon Apr 29 2024 Key Messages: 1. Showers and embedded thunderstorms return late tonight and into Tuesday. Discussion: Main forecast concern for the short term period revolves around what to expect with rain chances tomorrow. An upper trough will approach from the west late tonight and into Tuesday morning. This will usher in widespread showers and even some embedded thunderstorms to the forecast area after roughly 09z or so early Tuesday morning. As the day progresses the southern end of this wave attempts to transition to a closed low, likely slowing down the departure of rainfall tomorrow. Stuck with the NBM PoPs for this event which are pretty high through the day tomorrow. But I`m not particularly confident if likely PoPs well into the afternoon hours will be justified or not. I`m very confident showers will be around later in the day, just not so much on whether the coverage will be great enough to warrant the high rain chances. My initial gut reaction to this pattern is that the wave of showers and embedded thunderstorms pushing in from the west just before daybreak weakens or moves east of the CWA by midday, leaving us with a lull in rainfall activity until mid afternoon when redevelopment of scattered showers occurs. Severe storms do not appear to be a concern whatsoever as instability will barely be enough to support thunder, much less any severe storms. And rainfall amounts should remain within reason so flooding doesn`t appear to be a concern either. && .LONG TERM... (Tuesday night through next Monday) Issued at 244 PM EDT Mon Apr 29 2024 Key Messages: 1. Above normal temperatures at least through next week, with the highest occurring on Thursday. 2. Active weather pattern to bring chances for showers and thunderstorms Friday through early next week. Discussion: At the start Tuesday night, showers and Thunderstorms will be moving out of the area to the east after a cold frontal passage from earlier in the day. Wednesday will begin the considerable warm-up the forecast area will experience the rest of the period, with Thursday looking to be the warmest with mid to upper 80 highs in valley locations. For comparison for early May, Chattanooga averages around 78 degrees. The conditions will be as a result of surface high pressure building in as well as ridging aloft extending up from the Gulf, so dry weather can be expected through early Friday. Friday through the rest of the period Monday will be an active pattern with chances for showers and thunderstorms each day. Longwave troughing will situate to the north, sending shortwave troughs our direction through the weekend. At least two systems develop, maybe three, but the third is too far out in the forecast to know for certain. The first develops over the Central U.S. Thursday eventually becoming a deep low that tracks for the Upper Midwest/Western Great Lakes region. A cold front extending from it will approach the region Friday, eventually moving over the area late Friday into Saturday. This will be monitored for the potential for strong storms, but of course too early to know. Post FROPA, Saturday into Monday become more uncertain as the Friday system slows and hangs to our southeast, while another low pressure center looks to develop off the Central Rockies. The second system appears to take about the same track as the first towards the Upper Midwest region. So between those systems and potential moisture advection from the Gulf region as well, the Southeast U.S. will remain in an active and wet pattern. Temperatures do cool some from the mid to upper 80s Thursday to upper 70s to low 80s the rest of the weekend and long term period. && .AVIATION... (00Z TAFS) Issued at 708 PM EDT Mon Apr 29 2024 The evening and the first half of the night will be fairly quiet aviation-wise with lighter winds and mainly mid to high clouds. Towards the early morning, showers and embedded thunderstorms will arrive from the west, first impacting CHA, then TYS followed by TRI. The intensity is expected to decrease as they move east, but MVFR reductions are expected at all of the sites. Some improvement to VFR is likely at CHA and TYS, but TRI is forecast to stay MVFR through the day. Additional showers and storms will develop in the afternoon hours with a PROB30 included in CHA. However, any of the sites could see impacts from this additional development. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 63 76 58 84 / 90 80 0 0 Knoxville McGhee Tyson Airport, TN 63 74 58 80 / 60 80 20 0 Oak Ridge, TN 62 74 57 82 / 80 80 20 0 Tri Cities Airport, TN 58 75 57 79 / 0 90 30 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...CD LONG TERM....KS AVIATION...BW