Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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206 FXUS64 KMRX 201914 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 314 PM EDT Thu Jun 20 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (This evening through Friday) Issued at 239 PM EDT Thu Jun 20 2024 A mostly sunny afternoon across the forecast area with temperatures at mid afternoon in the mid to upper 80s to near 90. A drier airmass is in place with scattered cumulus and dew points in the lower to mid 60s. Current forecast will continue as is except a degree or two warming for Friday. Upper ridge is still holding strong over the mid Atlantic and Ohio Valley this afternoon. Winds are light and variable as well and heat index values are only in the lower 90s at mid afternoon. For the next 24 hours the center of the ridge shifts west and will be almost overhead Friday. Expecting temperatures to be slightly warmer Friday but no significant changes in the forecast. Heat index values will reach the mid to upper 90s Friday afternoon. && .LONG TERM... (Friday night through next Thursday) Issued at 239 PM EDT Thu Jun 20 2024 Key Messages: 1. Above average temperatures continue with strong ridging in place. 2. Increasing rain chances Sunday into early next week. Discussion: Anomalously high 500 mb heights will continue to bring subsidence to the area through Saturday, leading to above normal temperatures and dry, stable conditions. Some isolated, short- lived showers and storms may be possible in the higher terrain Saturday afternoon. The upper ridge retrogrades and flattens across the Ohio Valley on Sunday as a shortwave trough and associated surface front moves eastward across the Great Lakes and Ohio Valley. Greater low level moisture ahead of this trough/front and lower upper heights will increase instability, with higher probabilities for showers and thunderstorms starting on Sunday and continuing through the first half of next week. The highest chance of precip appears to be Sunday afternoon and Sunday night with the passage of the aforementioned shortwave trough and surface front. Behind this system, we will have a SW low level flow that will maintain above normal temperatures with humid conditions on Monday and Tuesday, along with a chance of diurnal showers and thunderstorms. Models show a deeper trough that may bring higher rain chances to the area in the Wednesday/Thursday time frame, with potentially a break the the heat behind that system. && .AVIATION... (18Z TAFS) Issued at 140 PM EDT Thu Jun 20 2024 Upper and surface ridging persists across east Tennessee producing VFR conditions at all TAF sites through early tonight. Some MVFR fog is expected to form near TRI for a few hours Friday morning so included a 3 hour group at 5SM from 09-12Z Friday. Surface ridge along with a weak pressure gradient will keep winds light. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 72 94 72 95 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 69 93 71 94 / 0 10 0 10 Oak Ridge, TN 70 93 71 94 / 0 10 0 10 Tri Cities Airport, TN 65 91 67 92 / 0 10 0 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...TD LONG TERM....DGS AVIATION...TD