112 FXUS64 KMRX 091720 AAA AFDMRX Area Forecast Discussion...UPDATED National Weather Service Morristown TN 120 PM EDT Mon Jun 9 2025 ...New AVIATION... .UPDATE... Issued at 1019 AM EDT Mon Jun 9 2025 Showers and storms across AL will be tracking NE, and are expected to reach our southern counties in the 2-4 pm EDT time frame. The HRRR appears to be depciting this activity pretty well, and it shows a decreasing trend to intensity and coverage as it approaches. The risk of severe hazards from these storms is very low, as we are lacking instability this morning, and increasing cloud cover will further inhibit destabilization. It will also affect the storms that will approach from the west later this afternoon (currently entering the NW corner of Middle TN), likely entering the Plateau in the 6-8 pm EDT time frame. Cloud cover and preceding showers in southern sections will reduce the potential for severe storms there, but the northern Plateau areas that are not impacted by the earlier showers/storms may have enough instability present to support strong to borderline severe storms with a damaging wind threat. Overall, the forecast looks pretty good with the above scenario, but a few adjustments will be made to PoP/Wx grids. && .SHORT TERM... (Today and tonight) Issued at 208 AM EDT Mon Jun 9 2025 Key Messages: 1. A low risk for strong to severe thunderstorms late this afternoon and evening. Wind gusts up to 60 mph are the main threat. 2. Some isolated flooding issues will be possible due to saturated soils from previous rains. 3. Some spotty showers or storms will continue overnight. Discussion: In the upper levels, a closed low is moving through the Great Lakes region today and tonight bringing a trough all the way to the Gulf Coast. At the surface, a low over Ontario will bring a cold front through the Ohio and Tennessee Valleys today. The front will move through the local region tonight. A line of showers and storms will move through the region late this afternoon and evening. CAMs are consistent with a progressive line or cluster moving through from 3pm to 11pm. HRRR has the line weakening a bit as it moves east through the region. With timing expected to be during max heating instability will be good with CAPE around 1000-1500 J/kg around Knoxville and southward. Generally under 1000 J/kg to the north. Effective shear is not great around 20 to maybe 30 knots. The tornado threat should be very low with 0-1km SRH below 50 and 0-1km shear around 10 knots. Large hail will be hard to achieve with the freezing level very high around 13k feet. The main threat will be damaging straight-line winds. DCAPE is very high on forecast soundings around 800 to 1000J/kg since there is dry air near the surface helping winds aloft descend. This activity should be moving fast enough to pose a minimal flooding threat but with saturated soils from this never-ending wet pattern, flooding issues will be possible during the heaviest downpours. We can also expect more trees to be downed by winds when soils are wet. After midnight, shower and storm activity will become more isolated and the severe threat should be over. I think clouds will linger long enough to prevent dense fog formation overnight but that will be something to watch for if rain and clouds clear out earlier than forecast tonight. && .LONG TERM... (Tuesday through Sunday) Issued at 208 AM EDT Mon Jun 9 2025 Key Messages: 1. Warm and mostly dry mid-week, though a few showers and storms cannot be ruled out primarily south of I-40 Thursday afternoon. 2. Shower and storm chances become more widespread each afternoon Friday into the weekend. For now there is low potential for stronger storms with heavy downpours. Discussion: Drier air working its way in post cold front means most locations will be dry on Tuesday though can`t rule out a shower over mountains along the NC border. This likely makes Tuesday the best day of the week between reasonable temperatures and the drier air. As the week progresses, a high pressure ridge will build over us before moving off to the east late week, and temperatures will climb into the upper 80s. Thursday carries low rain chances, mainly in southeastern Tennessee into southwestern North Carolina, as the beginning of moisture return and a weak impulse might trigger a few showers and a thunderstorm or two. Shear is weak and CAPE okay so nothing spectacular. By the end of the week a trough will be moving along the southern US underneath the far northern jet. Returning moisture should provide for better CAPE and power the next round of more widespread showers and thunderstorms Friday and into the weekend. GFS soundings depict very moist sounding profiles over the weekend with tall and skinny CAPE. Euro and both ensembles have the more consistent depiction of the southern shortwave being slow to progress while sandwiched between two upper ridges, so rain and thunderstorms seem a good bet to be spotting around the region into the weekend. As far as potential severe, it looks fairly limited with both of the global models depicting light to marginal deep layer shear over the weekend, so storms will be more typical summer type vibes. Not sure if there`s any potential risk for flooding at this point yet, storm motions will be slower and we`ll be coming off a couple days to dry out. The better takeaway is the morning hours are best to get outdoors work done before the heat, the humidity, and the storms show up this weekend. && .AVIATION... (18Z TAFS) Issued at 116 PM EDT Mon Jun 9 2025 Showers in northern GA are spreading north, but are showing a dissipating trend. A shower may be near CHA in the next few hours, but most showers/storms will come after 20Z we a convective line approaches from the west. This line will reach TYS and TRI in the 22-00Z time frame, and may bring gusty winds and MVFR cigs at times. It will exit the area bey midnight, and MVFR cigs are expected to develop in the moist air mass late in the night. Fog is possible as well but confidence in that is low at this time. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 87 66 85 63 / 60 60 10 0 Knoxville McGhee Tyson Airport, TN 85 65 82 60 / 70 80 10 0 Oak Ridge, TN 85 64 82 59 / 80 70 10 0 Tri Cities Airport, TN 82 63 79 56 / 30 70 10 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...McD LONG TERM....Wellington AVIATION/UPDATE...DGS