


Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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-- Discussion containing changed information from previous version are highlighted. --803 FXUS61 KPBZ 250908 AAA AFDPBZ Area Forecast Discussion...UPDATED National Weather Service Pittsburgh PA 508 AM EDT Wed Jun 25 2025 .SYNOPSIS... Hot and humid conditions will continue today. Shower and thunderstorm chances will increase as a cold front approaches. A few storms could be severe with damaging wind gusts and heavy rain. The front will stall across the area through the weekend, with daily shower and thunderstorm chances continuing. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...-- Changed Discussion --KEY MESSAGES: - Extreme Heat Warning/ Heat Advisory in effect until 5pm - Showers and thunderstorm chances increase through the day - Marginal Risk for severe storms and locally heavy rainfall --------------------------------------------------------------- Update... Added POPs for isolated showers and thunderstorms early this morning along an old outflow boundary from near Clarion to eastern Allegheny county. This boundary should exit the forecast area after sunrise. Previous... The persistent upper high will begin to drift southward today. A shortwave trough, and an associated surface cold front, will track along the northern periphery of the high by this afternoon. Expect showers and thunderstorms to increase in coverage through the day as this front and shortwave approach. SB CAPE is progged to range from 1500-2500 j/kg by this afternoon, with little shear in place. Dry mid level air will enhance the DCAPE, with values around 1000 j/kg expected. This will result in a damaging wind potential for storms that become organized. Weak flow aloft will also likely result in slow storm motion today. In addition, PWATS from 1.7 to 1.9 will also result in a localized heavy rainfall and flash flood potential, especially for areas that see repeated thunderstorms. Will continue to include this potential in the Hazardous Weather Outlook. Hot and humid conditions will continue, at least until convection fires this afternoon. Dropped a portion of the Heat Advisory for areas along and north of I-80, and for the ridges of PA and WV, where heat indices should stay in the 90s. Maintained the heat headlines elsewhere, though did push the expiration time up to 5 pm, when we should see cloud cover and shower/storms across the region.-- End Changed Discussion --&& .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... KEY MESSAGES: - Locally Heavy Rainfall Through Friday - Daily showers and thunderstorms, especially in the afternoon and evening - Strong storms possible each afternoon and evening ---------------------------------------------------------------- Ongoing convection in the evening, along with the marginal severe and heavy rain potential, should gradually wane as instability slowly diminishes. A few showers or thunderstorm is possible overnight with some lingering elevated instability, and the front stalled across the region. Patchy fog and stratus is expected, especially where partial clearing occurs, and where rain fell during this afternoon. The quasi-stationary front is expected to lift northward on Thursday, as another shortwave tracks along the northern periphery of the upper high. Expect showers and thunderstorms to increase in coverage again, peaking in the afternoon and early evening. The mid levels moisten some over what is expected to be seen Wednesday, though enough dry air is in place to again result in some wind gust potential with any more organized storm. CAPE is progged to range from 1500-2000 j/kg by afternoon, with little shear in weak flow aloft. An increasing potential for locally heavy rain and flash flooding is expected. Will monitor conditions over the next few days for any need of a flood watch. HREF PWATS are progged at 1.6 to 1.8, with the weak flow aloft resulting in slow storm motions. Convection should again wane Thursday evening with the loss of daytime heating and diurnal instability, and as the surface front lifts northward, as surface low pressure tracks along the front into Michigan. A general lull in the activity is expected Friday morning, before showers and storms increase again by afternoon as the surface low tracks across the Lower Great Lakes and southern Ontario. The low will pull a cold front back to the south, approaching the Upper Ohio Valley region in the afternoon. More organized storms are possible. The potential for gusty wind will continue in some storms with dry mid level air enhancing the DCAPE. PWATs are expected to lower somewhat on Friday, though with relatively weak flow aloft a locally heavy rain/flood potential will continue with slow storm movement. Convection should again wane in the evening with the loss of diurnal instability. Very warm and humid conditions will continue through the period. && .LONG TERM /SATURDAY THROUGH TUESDAY/... KEY MESSAGES: - Active weather continues with daily shower and thunderstorm chances into the start of next week - Potential for storms and locally heavy rainfall through the period ------------------------------------------------------------------- Model ensembles indicate westerly flow aloft across the Upper Ohio Valley region through the weekend. Shortwaves embedded in this flow will continue to result in daily showers and thunderstorms, with the greatest coverage in the afternoon and evening hours. Elevated PWATs will maintain a locally heavy rainfall potential as well. A deepening trough is then expected to track from the Upper Midwest to the Great Lake and Upper Ohio Valley region early next week. This will maintain showers and thunderstorms in the forecast. The trough axis, and a surface cold front, is currently progged for a Tuesday passage. A break from the active pattern is expected after FROPA. Temperatures are expected to continue to range from 5 to 10 degrees above average for much of the long term period. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... VFR is expected through Wednesday morning under an upper high. Evening convection has diminished, with no additional impacts to the airports expected. The upper high is expected to drift south today, as a shortwave trough and surface cold front track along its northern periphery. Showers and thunderstorms are expected to increase in coverage through the day with building diurnal instability. Included a TEMPO for MVFR thunderstorms in the tafs, with the most likely time of thunderstorm occurrence at each airport. Strong wind gusts are possible with any more organized storms. Convection should gradually diminish this evening with the lessening of diurnal instability. Some partial clearing is also expected, but this clearing should result in IFR fog and stratus development with low level moisture in place. Outlook... Showers and thunderstorms are expected through the weekend, especially during the afternoon and evening hours, as a series of disturbances cross the Upper Ohio Valley region. Periodic restrictions are expected in these storms. In addition, overnight/early morning fog and stratus are also possible especially for areas that see rainfall on any particular day. && .CLIMATE... Daily record high maximum (left) and daily record high minimum (right) temperatures for Wednesday and Thursday are listed below. Wednesday June 25th Pittsburgh, PA: 98F (1988) 75F (1952) Zanesville, OH: 101F (1988) 72F (1952) Morgantown, WV: 94F (1921, 1952, 1988) 74F (1952) Dubois, PA: 91F (1966) 67F (2000) Wheeling, WV: 97F (1943) 75F (1952) New Philadelphia, OH: 92F (1966, 2002, 2005) 68F (2013) Thursday June 26th Pittsburgh, PA: 95F (1966) 75F (1952) Zanesville, OH: 97F (1952) 73F (1952) Morgantown, WV: 96F (1952) 74F (1952) Dubois, PA: 91F (1966) 66F (2000) Wheeling, WV: 96F (1943, 1952) 73F (1952) New Philadelphia, OH: 99F (1988) 71F (2022) && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...Heat Advisory until 5 PM EDT this afternoon for PAZ013-022-031- 077. Extreme Heat Warning until 5 PM EDT this afternoon for PAZ014- 020-021-029-073-075. OH...Heat Advisory until 5 PM EDT this afternoon for OHZ039>041- 048>050-057>059-068-069. WV...Heat Advisory until 5 PM EDT this afternoon for WVZ001>004-012- 021-509-510. && $$ SYNOPSIS...WM NEAR TERM...WM SHORT TERM...WM LONG TERM...WM AVIATION...WM CLIMATE...