FXUS61 KPBZ 150627 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 227 AM EDT Wed Apr 15 2026 .WHAT HAS CHANGED... The Slight and Marginal severe risk areas were pulled slightly north as compared to the previous forecast. Also, the Marginal Risk for Thursday has been expanded to encompass most of the forecast area. Potential storm placement and timing for today was refined slightly, focusing on areas north of I-70 after 21Z or so. && .KEY MESSAGES... 1) Slight Risk (level 2 of 5) of severe storms today north of I-70. Damaging wind is the main threat, although large hail and a tornado or two are possible. 2) Thursday features a Marginal Risk (level 1 of 5) of severe storms, with isolated damaging wind possible. After a break Friday, a stronger front could bring more severe weather Saturday. 3) Anomalously warm temperatures this week. Daily record high max and minimum temperatures will be challenged and possibly broken, especially today. && .DISCUSSION... KEY MESSAGE 1... A remnant MCV is progressing eastward across southwest PA during the overnight period. Earlier small hail-producing cells to the north of the MCV have moved east and dissipated, leaving a temporary lull in precipitation. Towards sunrise, what should be the weakening remnants of the Michigan QLCS will approach areas north of I-80. CAMs agree on this fading trend as the low- level environment should generally be hostile to convection at that time due to relatively meager MLCAPE and increasing MLCIN. Impact should be limited to brief heavy rain and perhaps modestly gusty wind. The environment will improve markedly during the daylight hours as southwest flow brings improved moisture flow into the region. The axis of highest moisture, featuring precipitable water values of 1.25 to 1.5 inches, will lie north of I-70. This is where the bulk of the storm activity and severe potential is forecast to occur this afternoon and evening, tracking E or ENE. Accordingly, along with some measure of surface heating, this should allow surface-based CAPE to easily reach the 1000-1500 J/kg range according to HREF means, with potential to reach 2000 J/kg in the event of stronger heating. Deep shear will be improved as compared to yesterday, reaching the 35-40 knot range for 0-6km values. Storm initiation likely occurs to our west, perhaps aided by a weak mid-level wave, with activity potentially spreading in from the west after 21Z or so. Storm mode could be mixed, with short line segments/bows, and potentially supercellular structures, especially if discrete storms can form earlier over our region along remnant boundaries. The main threat remains damaging wind gusts over most of the region. Better potential for large hail and perhaps a tornado or two lies generally north of Pittsburgh, where low- level SRH is maximized, LCLs are a bit lower, and CAPE in the hail growth zone is more abundant. The new SPC day 1 outlook is in good agreement with the above, leaving a Slight Risk (level 2 of 5) in place north of I-70. Also remember: the threat of flash flooding cannot be ignored, as isolated issues could occur in locations that are impacted by multiple storms. While the severe threat should largely subside by midnight due to diurnal stabilization, upstream convection could once again impact the region overnight into Thursday morning, at least in a weakening state. Such convection is tricky to time and depends at least partially on leftover boundaries from earlier activity. KEY MESSAGE 2... Thunderstorm potential continues on Thursday, as Great Lakes low pressure drags a weak frontal boundary or surface trough across the region. Although deep shear will be similar to Wednesday, more widespread cloud cover may hinder the buildup of instability. Less- favorable low-level hodographs and poor mid-level lapse rates point to lower tornado and hail potential, leaving isolated damaging wind as the most likely impact from the stronger storms. The SPC day 2 Marginal Risk (level 1 of 5) area was expanded to cover most of the forecast area north and west of Morgantown. A crossing shortwave accompanying the surface low, dipping into the Tennessee Valley, may finally dislodge the southeast CONUS ridge Thursday night while bringing overnight showers and storms to our region. Friday and Friday night may feature a dry break as a smaller- scale 500mb ridge crosses. Then, one last round of strong to potentially severe storms will arrive with a stronger cold front Saturday afternoon/evening, followed by decreasing precipitation and more seasonable temperatures for Sunday. KEY MESSAGE 3... A anomalously strong (500mb heights at the 99th percentile) and stubborn ridge remains centered over Florida and extending across the southeast CONUS into Thursday, before being weakened some by upstream shortwave activity. It still appears that today will feature the best chances of record-breaking temperatures. Warm and moist southwest flow today will push 850mb temperatures into the 14 to 16C range, which will allow temperatures to rise into the mid 80s assuming decent sunshine/mixing. Such temperatures are most likely south of Pittsburgh away from the ridges, while areas to the north feature more cloud cover and better precipitation chances. This is reflected in NBM temperature record probabilities for today. Sites PHD (shorter climate record), HLG, and MGW all have 85% or greater probability of reaching record highs today according to statistical guidance. Probabilities for ZZV and PIT are lower given a bit better cloud/rain potential and longer climate histories. There are also decent probabilities both today and Thursday for record warm minimum temperatures, with PIT, PHD, and HLG featuring 70% or greater chance of setting such standards both days. Thursday remains warm, with 60% or greater probability of temperatures of 80 or higher south of I-80, but a bit more areawide cloud cover and shower activity may hinder the potential of record highs (probabilities drop below 30% areawide). The next best shot for these may be Saturday, with perhaps some sun and southwest flow ahead of an approaching front. The warmth definitively ends by Sunday behind this boundary. Minor heat risk continues areawide today and Thursday before retracting some on Friday. Heat impacts will primarily be felt by those who are extremely sensitive to heat and those without cooling/hydration. Speckled moderate risk areas are indicated today and Thursday especially, mainly in the Ohio and Mon river valleys. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... VFR prevails to begin the TAF period and much of the forecast is expected to be VFR as well. This will possibly be broken by several chances for showers and storms. The first of which largely occurs between 10-14z when the ongoing line of storms in Michigan is expected to encroach upon the region. By the time it gets here, it will likely be a broken line of dying showers and may fracture further before even making it to BVI or anywhere further south. These showers could bring MVFR restrictions in VIS to affected ports and lowering chances for MVFR CIGs at FKL and DUJ which have seen CIG forecasts improve this cycle. These showers have been included as TEMPOs for FKL/DUJ, PROB30s as far south as HLG/AGC/LBE and are not mentioned further south. After these early showers decay, widespread VFR and dry weather returns until the afternoon, when storms begin to spark again. The outlook for tomorrow afternoon remains similar to yesterday, with a wide range of timing and coverage solutions at play. Currently storms are favored largely north of I-70 this afternoon and evening, possibly beginning again by early afternoon closer to I-80 first. Most model solutions then bring additional lines of storms across the region (highest chances again north of I-70) after sunset. Storm coverage may be more limited in the afternoon before becoming more widespread in the evening, but both timeframes look to support hail and damaging wind gust threats. Both of these possible storm timings have been included as PROB30 groups for affected ports trying to forecast the best time. This remains rather difficult though, with storm timing and location being largely dependent on the existence and placement of boundaries tomorrow morning from ongoing convection tonight. MGW may find it self far enough south to miss out on all of this activity and could be VFR and dry through the entire TAF period. ZZV could also luck out but has a higher chance than MGW to see storms tomorrow evening. Again, large portions of the forecast period will be VFR but instances of restrictions in showers and storms are possible mainly north near sunrise and tomorrow afternoon and then a little more widespread by evening time. Outlook... The Upper Ohio River Valley will remain positioned near the upper ridge axis throughout the week and make it liable for multiple shortwave crossing to foster periodic showers/thunderstorms and precip-driven restrictions. A pattern shift is unlikely to occur until late Sunday into Monday before confidence becomes high again on a prolonged period of dry, VFR weather. && .CLIMATE... See below for record max highs and max lows this week: Today, April 15th: Max High Max Low Pittsburgh, PA: 85F (1883) 61F (1967) Wheeling, WV: 82F (2010) 59F (2002) Morgantown, WV: 86F (1993) 65F (1967) New Philadelphia, OH: 82F (2010) 58F (2023) Zanesville, OH: 85F (1941) 61F (1972) DuBois, PA: 79F (2003) 56F (2002) Thursday, April 16th: Max High Max Low Pittsburgh, PA: 86F (2002) 63F (2017) Wheeling, WV: 86F (1945) 64F (2002) Morgantown, WV: 88F (2002) 64F (2012) New Philadelphia, OH: 85F (2002) 62F (2017) Zanesville, OH: 86F (2002) 65F (1912) DuBois, PA: 82F (2012) 59F (1976) Friday, April 17th: Max High Max Low Pittsburgh, PA: 87F (1896) 63F (1896) Wheeling, WV: 84F (2002) 64F (2002) Morgantown, WV: 89F (1976) 64F (1960) New Philadelphia, OH: 84F (2002) 60F (1982) Zanesville, OH: 88F (1896) 66F (1896) DuBois, PA: 83F (2002) 60F (2002) Saturday, April 18th: Max High Max Low Pittsburgh, PA: 90F (1896) 64F (1896) Wheeling, WV: 85F (2025) 63F (2002) Morgantown, WV: 92F (1976) 64F (2013) New Philadelphia, OH: 86F (1976) 57F (2019) Zanesville, OH: 92F (1896) 66F (1896) DuBois, PA: 87F (1976) 61F (2002) && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ DISCUSSION...CL AVIATION...Cermak/AK