####018004802#### FXUS61 KPBZ 161650 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1250 PM EDT Sun Aug 16 2026 .WHAT HAS CHANGED... There is higher confidence in the potential for severe thunderstorms this afternoon, given clearing skies to the west allowing for increased instability. Beyond this evening, little change was made to the forecast. && .KEY MESSAGES... 1)Severe weather and flash flooding risks continue this afternoon and evening with renewed thunderstorm development. 2) After lingering showers dissipate Monday, there is fairly high confidence in dry weather until Wednesday/Thursday, when the next front arrives. && .DISCUSSION... KEY MESSAGE 1... The region remains in a relative lull of activity between overnight/early morning activity and developing convection to the west, where a couple of Severe Thunderstorm Warnings are already in effect. The new activity is associated with a vort max/MCV over northwest Ohio. Ahead of this, a good deal of sunshine is allowing for a buildup of instability, and the HREF suggests that 1500-2500 J/kg of surface-based CAPE is likely by 18Z, mainly south of I-80. Other convective parameters look best from I-80 on south, roughly matching with the SPC Slight Risk area. In particular, a pocket of 25-30 knots of 0-6km shear is most likely in this region, supporting multicells with mainly a damaging gust potential where cold pools help consolidate into short lines. Lengthening low-level hodographs and sufficient 0-1km SRH continue to suggest a low-end tornado threat for any ESE-moving storms. Along with this the threat of flash flooding will continue to be monitored, especially in areas that got heavier rain overnight. This includes areas in eastern Ohio south of I-70, as well as a strip extending from New Philadelphia ENE towards Butler County. Although storms should be fairly progressive overall, the environment remains highly supportive for efficient rainfall production. The 12Z KPIT sounding recorded a precipitable water measurement of 2.15 inches, which is the 9th-highest recorded at the site since 1952. 2+ inch values remain in place through this evening, along with 11k to 13k warm-cloud depths. The Flood Watch will be maintained through tonight. KEY MESSAGE 2... Most of the convection should pull off to the east by 02Z-03Z, although a few showers/storms may linger behind the main line as another shortwave trough crosses in the mid-level zonal flow. One last ripple in that flow crosses on Monday, leading to showers and storms mainly south of Pittsburgh. Convective parameters are unfavorable for severe weather with this activity. Also, declining precipitable water values point to a decreasing risk for heavy rainfall. The Flood Watch expires at 8 AM Monday, and an extension may not be needed. High pressure building in from the Great Lakes should end precipitation by Mon evening. Dry weather is then favored until Wednesday, when the next front could potentially arrive, although this timing could change. At this time, severe weather and flooding risks appear low with this system, as supported by longer-range machine learning guidance. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Mainly MVFR cigs continue this afternoon ahead of an approaching prefrontal trough. A broken line of thunderstorms is expected to track east across the region this afternoon and evening along the prefrontal trough, with IFR restrictions. Some storms could contain damaging wind and heavy rainfall. Included a tempo mention in the tafs for the most likely time of arrival. Expect a gradual deterioration back to IFR tonight with low level moisture in place. The surface cold front is progged to track across the region Monday. Expect a gradual improvement in cig heights through the day with mixing and some dry advection after FROPA. Airports from near PIT and south could see a few afternoon showers or a thunderstorm as this front crosses. Outlook... Other than early morning fog, VFR is then expected through early Wednesday under high pressure. Restriction and shower/thunderstorm chances return Wednesday and Wednesday night with the approach and passage of a cold front. VFR returns Thursday and Friday under high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...Flood Watch through Monday morning for PAZ020-021-029-031- 073>076. OH...Flood Watch through Monday morning for OHZ039>041-048>050- 057>059-068-069. WV...Flood Watch through Monday morning for WVZ001>004-012-021- 509>514. && $$ DISCUSSION...CL AVIATION...WM ####018004853#### FXUS64 KOHX 161654 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 1154 AM CDT Sun Aug 16 2026 ...New SHORT TERM, LONG TERM... .KEY MESSAGES... Updated at 1107 AM CDT Sun Aug 16 2026 - Dangerous heat is expected through Monday with triple digit heat indices across most of Middle Tennessee. This is resulting in major to extreme risk for heat-related illnesses. Please take the necessary precautions to protect yourself and loved ones from this oppressive heat. - Medium storm chances on Monday may bring a damaging wind risk during the afternoon and evening hours, especially to areas east of I-65. - Extreme heat and humidity should be out of Middle TN by late week. && .SHORT TERM... (Rest of today through Monday) Issued at 1107 AM CDT Sun Aug 16 2026 Another scorcher is underway across Middle TN. This morning's upper air flights depicted a large 250 mb ridge over the Great Smoky Mountains. This is effectively creating a "heat dome" with subsidence trapping hot, moist air at the surface, resulting in dangerous heat indices for Middle TN. Expect another day of widespread heat indices above 105F today, maybe even hitting 110F in some areas with more urban sprawl. As such, the Extreme Heat Warning is in effect through 7PM tonight. Once that expires at 7PM, it will be immediately replaced by an areawide Heat Advisory through 7PM Monday. We'll barely get any relief overnight tonight with lows in the upper 70s. The upper level ridge will still be in place tomorrow, but gradually moderating back to more zonal flow, warranting one more day of heat headlines. Tomorrow should be the last day of extreme heat for several days. The cold front relieving us from the heat will be a double-edged sword tomorrow/Monday night. It also brings a threat of severe weather to areas east of I-65. Instability will be plentiful under a day of full sun and humidity prior to the front's arrival. The 16/12Z HREF suggests SBCAPE on the order of 2000 J/kg during the frontal passage between about 4PM and 8PM Monday. While there is very little shear to hold everything together, a strongly unstable environment with a cold front moving through will still have the forcing needed to produce damaging wind gusts. The bulk of the severe weather threat is over east Tennessee (where the best overlap of favorable ingredients is), but still expect to see a few hours of strong to severe storms mainly over the Plateau tomorrow afternoon and evening. && .LONG TERM... (Monday Night through next Sunday) Issued at 1107 AM CDT Sun Aug 16 2026 Behind the front on Tuesday, temperatures and resultant heat indices take a dip back toward normal. Keep in mind that it's still mid August, so "normal" is still hot, around 90 degrees. This relief will be short-lived due to a warm front lifting across the state on Wednesday, bringing us right back up to borderline Heat Advisory criteria. It's too early to make that call right now, but we may just skirt by without heat headlines on Wednesday. The majority of the warm front's impact will be felt over West Tennessee with heat indices around 105 toward the TN River, but it will be close. The pattern finally starts to mediate back toward climatological normals at the end of the week. By Thursday, zonal flow aloft will help send heat and humidity well below headline thresholds. By Friday, expect heat indices below 100 degrees areawide for the first time in over a week. This cooler trend continues through next weekend. && .AVIATION... (12Z TAFS) Issued at 628 AM CDT Sun Aug 16 2026 High pressure continues to dominate the weather across Middle Tennessee both at the surface and aloft. No active weather is expected. TAFs are VFR. && .PRELIMINARY POINT TEMPS/POPS... Nashville 78 96 73 92 / 0 30 30 0 Clarksville 77 93 70 91 / 0 20 20 0 Crossville 72 90 68 86 / 0 50 30 10 Columbia 77 98 73 94 / 0 20 40 0 Cookeville 73 91 70 88 / 0 50 30 10 Jamestown 72 89 68 86 / 10 60 20 0 Lawrenceburg 76 96 72 91 / 0 30 40 10 Murfreesboro 76 98 72 93 / 0 40 30 0 Waverly 76 94 71 92 / 0 30 30 0 && .OHX WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 7 PM CDT this evening for TNZ005>008- 023>030-056>064-075-093>095. Heat Advisory from 7 PM this evening to 7 PM CDT Monday for TNZ005>008-023>030-056>064-075-093>095. Heat Advisory until 7 PM CDT Monday for TNZ009>011-031>034-065- 066-077>080. && $$ SHORT TERM...Dirkes LONG TERM....Dirkes AVIATION.....Rose