Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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385 FXUS64 KMRX 062300 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 700 PM EDT Sat Jul 6 2024 ...New AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 251 PM EDT Sat Jul 6 2024 Key Messages: 1. Comfortable dewpoints and low temperatures in the 60s tonight. 2. Chance of showers tomorrow afternoon in the mountains and SW NC. Drier air has been building into the area through the day, and along with boundary layer mixing, dewpoints have dropped into the lower and mid 60s in many spots. A weak upslope flow is producing some isolated light showers in the mountains. This NW flow will shift around to N and E thorugh the night as the surface high over West TN moves to the upper OH Valley region. With a broad trough and jet streak to our NW, some scattered cloud cover may linger overnight, but with the falling dewpoints, lows should be mainly in the 60s overnight. Tomorrow, a SE low level flow will bring moisture and instability back toward the area, mainly in SW NC and the mountains, so we may see a little better coverage of showers in that area during the afternoon. Valley locations should stay dry with highs in the lower 90s in most spots. && .LONG TERM... (Sunday night through next Saturday) Issued at 251 PM EDT Sat Jul 6 2024 Key Messages: 1. Heat indices of 100-105 degrees returns Monday and Tuesday as low- level moisture pulls back into the area. 2. Next week looks convectively active. High rain chances return later Monday and continue through the week. 3. Remains of BERYL with deep moisture may move into the Tennessee valley Tuesday night through Thursday. Locally heavy rains and localized flash flooding possible by late week but confidence of the track for timing of heavy rainfall is still low. Discussion: For the extended forecast an upper trough continues over the middle of the country with ridging aloft across the far southeastern part of the southeast United States. As a result a southwest flow aloft is in place over the eastern Tennessee Valley and Southern Appalachians with low level moisture increasing by Monday. The main weather story of the extended is the track of tropical system BERYL`s moisture with the potential for deep tropical moisture from the system mid to late in the week over the region which could lead to a better threat of isolated flash flooding. Increasing chances for showers and thunderstorms with highest coverage during the afternoon and evening hours. On Monday and Tuesday, a moist and unstable airmass will be over the forecast area with increasing coverage of showers and thunderstorms Temperatures will be warmest on these days too with highs in the lower to mid 90s. Heat Index values will be highest Monday and will be at heat advisory levels in the central and southern valley. On Tuesday heat index values will be slightly lower. Still looks like late Tuesday night through Thursday deep tropical moisture from the remnants of BERYL may move across the Tennessee Valley into the southern Appalachians. High PWs of 2.1 to 2.2 inches along with a high Theta-e ridge axis over the area could set the stage for locally heavy rainfall and flash flooding. The remnant surface low that was Beryl is forecast to be over the Ohio and Tennessee Valleys. Highs Wednesday and Thursday will be cooler with more clouds and precipitation, only in the mid 80s to around 90. Friday and again Saturday the surface low shifts northeast and its deep sub-tropical moisture may move with it as upper ridging strengthens across the southern Appalachians. Any leftover moisture will still make it feel muggy and temperatures will again rise into the lower 90s. There will still be high chances of showers and storms only slightly less coverage. && .AVIATION... (00Z TAFS) Issued at 658 PM EDT Sat Jul 6 2024 VFR conditions and fairly light winds are expected tonight. Patchy fog development is possible in some locations by the early morning, but impact at any of the terminals looks unlikely at this time. During the day on Sunday, winds will be generally from the north to northeast at around 10 kts with FEW/SCT clouds at or above 5,000 feet AGL. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 71 95 75 96 / 10 10 20 60 Knoxville McGhee Tyson Airport, TN 69 93 73 93 / 0 20 20 60 Oak Ridge, TN 68 93 72 93 / 0 10 10 50 Tri Cities Airport, TN 66 91 69 91 / 10 20 20 60 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DGS LONG TERM....TD AVIATION...BW