902 FXUS64 KMRX 060208 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1008 PM EDT Wed Apr 5 2023 ...New UPDATE... .UPDATE... Issued at 959 PM EDT Wed Apr 5 2023 Areas of showers across middle Tennessee continues to decay this evening with outflow moving east across the local area. Hi-res guidance indicates limited rainfall through the overnight period and mainly focused across the Cumberland Plateau. Most of the forecast is on track. Made adjustments to hourly weather elements through the night based on trends in observations. && .SHORT TERM... (This evening through Thursday) Issued at 306 PM EDT Wed Apr 5 2023 1. Near record high temperatures today across the TN Valley. 2. Rain chances increase late this evening ahead of an approaching cold front that will bring showers and thunderstorms across the area Wed night and Thursday. Discussion: Southwesterly flow is still over our area this afternoon pulling warm gulf air to TN as the upper ridge is pushed east. Current temps in the TN Valley are already in the mid and upper 80s-approaching (and exceeding) record highs at multiple sites. The strong low pressure moving from the plains towards the Great Lakes region will pull a cold front across TN overnight and through tomorrow, which will be the cause of the expected showers and thunderstorms. A few isolated showers are possible in the east TN mountains this afternoon and evening, but the main line of storms will approach our area from the west overnight. Showers will reach the Cumberland Plateau between 10pm and midnight and progress east across the valley. This system will bring showers and a few thunderstorms, some of which could produce gusty winds, but the overall severe threat continues to be low for our area. The front begins to stall as it becomes parallel with the southwesterly flow, so will be slow to move through our area, leading to a prolonged stint of rain chances in the forecast that carry over into the long term forecast. QPF values are low (between 0.15 and 0.50")for the Wed night through Thursday night time frame, so flooding is not a concern at this time. && .LONG TERM... (Thursday night through next Wednesday) Issued at 306 PM EDT Wed Apr 5 2023 Key Messages: 1. Prolonged period of rainy and cloudy weather from Thursday night through Saturday night as a slow moving front stalls just to the southeast and remains nearby. 2. Dry conditions and a warming trend expected from Easter Sunday through the middle of next week. Discussion Thursday night, a cold front will have or is forecast to be just east of the Southern Appalachians with much colder temperatures Thursday night. Friday and Saturday will be much cooler as well with highs only in the 50s. Went on the cool side of guidance on Friday with all the clouds and moderate rainfall. Shortwaves will travel northeast along the front and moisture overrunning the front will keep clouds and showers across most the forecast area Friday through Saturday with the heaviest rainfall in the extreme south, finally shifting east Saturday night. Rainfall amounts will be around 0.5 inches extreme northern areas but 1 to 2 inches across most of the area. Higher rainfall amounts of over 2 inches is possible in southeast Tennessee and southwest North Carolina. The heaviest rainfall is expected to be late Friday night and Saturday morning as a significant shortwave moves north of the old frontal boundary. There will be some weak instability Thursday night across southern and eastern sections of the forecast area closer to the front so have a chance of thunderstorms there and also Friday in the extreme southeast. The clouds and light rain showers will linger through Saturday until the front moves away Saturday night and higher pressure builds in from the north and northwest. The highest surface pressure will be to the northeast but ridging aloft building in from west of the east Tennessee Valley towards the northeast part of the country will be strong enough to keep the old frontal boundary from the weekend from moving back too far north. Drier and warmer conditions will be the trend from Easter Sunday through the middle of next week. Highs will rise from the 60s Sunday to the mid to upper 70s by Wednesday. && .AVIATION... (00Z TAFS) Issued at 726 PM EDT Wed Apr 5 2023 A line of showers is moving east across central Tennessee and is weakening as it approaches the area. This activity will continue to weaken and don't expect any rain showers to impact the terminals tonight. CIGs will lower overnight and especially in the morning hours Thursday with MVFR CIGs before slight improvement back to VFR in the afternoon. Confidence in rain Thursday afternoon is still low and continued with PROB30's for all sites. Occasional MVFR CIGs will be possible in areas of heavier rain. Winds will decrease overnight with W/NW winds around 5-10 knots on Thursday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 63 80 53 60 / 20 50 60 80 Knoxville McGhee Tyson Airport, TN 64 77 51 57 / 10 60 60 80 Oak Ridge, TN 64 74 49 59 / 30 70 60 70 Tri Cities Airport, TN 61 76 49 55 / 30 70 60 80 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... AVIATION...