FXUS61 KPBZ 091725 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 125 PM EDT Thu Jul 9 2026 .WHAT HAS CHANGED... A Flood Watch was issued for areas south of I-70, as heavy rain potential for this afternoon has increased in this area. A further slight increase to precipitation probabilities was made for Saturday. Little change was made to the forecast from Sunday on, when dry and warmer weather begins to arrive. && .KEY MESSAGES... 1) Flood Watch issued south of I-70 where most heavy rain potential is expected; low potential of strong downburst gusts 2) Unsettled pattern continues through Saturday, with periodic showers and thunderstorms 3) Mainly dry and warm Sunday into next week && .DISCUSSION... KEY MESSAGE 1... A shortwave trough will continue to track across the Upper Ohio Valley and the Appalachians through this afternoon. In the wake of overnight/early morning showers and thunderstorms, more activity has formed mainly south of Pittsburgh, particularly across northern West Virginia. Additional development is likely into the afternoon, with lift supported by the shortwave as well as the right exit region of an upper jet to our northeast. This rain will occur in an environment characterized by deep moisture (1.8-1.9 inch precipitable water), around 1000 J/kg of mixed-layer CAPE and weak shear. Given the lack of flow and insufficient DCAPE, the severe wind threat is judged to be very low. The main threat will continue to be heavy rainfall, given the above parameters and favorably saturated soundings with deep warm cloud depths, promoting efficient rainfall. Have already issued a Flood Watch for flash flooding for much of the area south of I-70 through 10 PM, and a Flash Flood Warning is in effect for portions of northern West Virginia. Additional rain of 1-2", perhaps falling in 1-2 hours, with peaks of 3" appear possible given HREF max precip potential plots. More isolated activity to the north of the Flood Watch should provided only very isolated heavy rainfall totals. DCAPE is also a little better in this area, so a few mostly sub-severe downburst wind gusts may be possible. Most available guidance shows mainly isolated activity at best during the overnight period with the loss of heating and the departure of the shortwave. However,given potential lingering boundaries from daytime activity and the events of the past few nights, we cannot rule out a localized instance or two of heavy rainfall prior to sunrise Friday. KEY MESSAGE 2... The next shortwave will ride along the Ohio Valley through tonight and arrive in our region towards sunrise on Friday. Also, a surface boundary is forecast to drift into our region from the north. This should lead to greater coverage of showers and thunderstorms from midday into the evening hours. Another Flood Watch may be necessary, this time for a larger area, as PWATs and instability values will be similar to today. Increased flow aloft should result in a slightly faster storm motion, and with 0-6km shear of around 25 knots, there is slightly more potential for convective organization and strong to severe wind gusts. The boundary may stall at least briefly in the general vicinity of the Mason-Dixon Line Saturday afternoon and evening, with a continued threat for showers and thunderstorms. This may keep at least a localized threat for additional heavy rainfall totals and flooding in areas south of I-70. KEY MESSAGE 3... The boundary should get a push from a northeast CONUS shortwave Saturday night, allowing the front to clear the area and shift flow aloft to a northwesterly direction by Sunday. A period of dry weather is forecast from Sunday into early next week as surface high pressure takes control. Temperatures will be on the rise as well, as a strong ridge builds eastwardfrom the central CONUS. At this time, heat levels are not expected to match those of last weekend, but max temps in the upper 80s to around 90 are possible come Tuesday/Wednesday. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... General VFR conditions will prevail through tonight, but scattered showers and thunderstorms will redevelop this afternoon primarily from Pittsburgh on south as another shortwave crosses. Embedded heavy rain with PWAT values >1.5" and tall, skinny CAPE profiles will result in periodic but impactful visibility restriction to a mile or less akin to observations from this morning in similar conditions. Included PROB30 for TSRA for most airports north of the I-70 corridor, with a TEMPO mention to the south where more coverage is expected. Some development off of the lake breeze could impact FKL/DUJ, but drier air up that way may inhibit updrafts from getting very tall. Nonetheless, also have PROB30s there. Elsewhere outside of precip, VFR diurnal cu will prevail with 5-10 knot west-southwest wind. Convection should wane by evening as the shortwave axis exits to the east, though some hi-res guidance maintains widely scattered showers overnight ahead of yet another shortwave progged to cross on Friday, so for now kept VCSH mention in for the overnight period. Showers and storms, likely more widespread, develop again on Friday focused along a convergence axis with a southward moving boundary and shortwave support. The stronger storms, again, will bring periodic restrictions in TSRA with heavy rain and gusty wind potential. The most likely timeframe falls just outside the current 24 hour TAF period, so have only included mention at the tail end of the PIT TAF for now. Outlook... Shower and thunderstorm chances continue Saturday as a surface front becomes stationary near or south of a ZZV-MGW corridor. Generally dry weather and VFR should return Sunday and Monday as high pressure builds in. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...Flood Watch until 10 PM EDT this evening for PAZ031-075-076. OH...Flood Watch until 10 PM EDT this evening for OHZ059-068-069. WV...Flood Watch until 10 PM EDT this evening for WVZ003-004-012- 021-509>514. && $$ DISCUSSION...CL AVIATION...MLB